Exhibit 4.1

                    WELLS FARGO ASSET SECURITIES CORPORATION

                                   (Depositor)

                                       and

                             WELLS FARGO BANK, N.A.

                                (Master Servicer)

                                       and

                         U.S. BANK NATIONAL ASSOCIATION

                                    (Trustee)

                         POOLING AND SERVICING AGREEMENT

                           Dated as of March 30, 2006

                                 $953,944,125.58

                       Mortgage Pass-Through Certificates
                                  Series 2006-4

<PAGE>

                                TABLE OF CONTENTS



                                    ARTICLE I

                                   DEFINITIONS

Section 1.01  Definitions..................................................
Section 1.02  Acts of Holders..............................................
Section 1.03  Effect of Headings and Table of Contents.....................
Section 1.04  Benefits of Agreement........................................


                                   ARTICLE II

                          CONVEYANCE OF MORTGAGE LOANS;
                      ORIGINAL ISSUANCE OF THE CERTIFICATES

Section 2.01  Conveyance of Mortgage Loans.................................
Section 2.02  Acceptance by Custodian......................................
Section 2.03  Representations and Warranties of the Master Servicer and
               the Depositor...............................................
Section 2.04  Execution and Delivery of Certificates.......................
Section 2.05  Designation of Certificates; Designation of Startup Day
               and Latest Possible Maturity Date...........................


                                   ARTICLE III

                ADMINISTRATION OF THE TRUST ESTATE; SERVICING
                              OF THE MORTGAGE LOANS

Section 3.01  Certificate Account..........................................
Section 3.02  Permitted Withdrawals from the Certificate Account...........
Section 3.03  Advances by Master Servicer and Trustee......................
Section 3.04  Custodian to Cooperate; Release of Owner Mortgage Loan
               Files and Retained Mortgage Loan Files......................
Section 3.05  Reports to the Trustee; Annual Compliance Statements.........
Section 3.06  Title, Management and Disposition of Any REO Mortgage
               Loan........................................................
Section 3.07  Amendments to Servicing Agreements, Modification of
               Standard Provisions.........................................
Section 3.08  Oversight of Servicing.......................................
Section 3.09  Termination and Substitution of Servicing Agreements.........
Section 3.10  Application of Net Liquidation Proceeds......................
Section 3.11  Assessment of Servicing Compliance; Registered Public
               Accounting Firm Attestation Reports.........................
Section 3.12  Exchange Act Reports.........................................


                                   ARTICLE IV

                    DISTRIBUTIONS IN RESPECT OF CERTIFICATES;
                         PAYMENTS TO CERTIFICATEHOLDERS;
                             STATEMENTS AND REPORTS

Section 4.01  Distributions................................................
Section 4.02  Allocation of Realized Losses................................
Section 4.03  Paying Agent.................................................
Section 4.04  Statements to Certificateholders; Reports to the Trustee
               and the Depositor...........................................
Section 4.05  Reports to Mortgagors and the Internal Revenue Service.......
Section 4.06  Calculation of Amounts; Binding Effect of Interpretations
               and Actions of Master Servicer..............................
Section 4.07  Determination of LIBOR.......................................
Section 4.08  Reserve Fund.................................................


                                    ARTICLE V

                                THE CERTIFICATES

Section 5.01  The Certificates.............................................
Section 5.02  Registration of Certificates.................................
Section 5.03  Mutilated, Destroyed, Lost or Stolen Certificates............
Section 5.04  Persons Deemed Owners........................................
Section 5.05  Access to List of Certificateholders' Names and Addresses....
Section 5.06  Maintenance of Office or Agency..............................
Section 5.07  Definitive Certificates......................................
Section 5.08  Notices to Clearing Agency...................................


                                   ARTICLE VI

                      THE DEPOSITOR AND THE MASTER SERVICER

Section 6.01  Liability of the Depositor and the Master Servicer...........
Section 6.02  Merger or Consolidation of the Depositor or the Master
               Servicer....................................................
Section 6.03  Limitation on Liability of the Depositor, the Master
               Servicer and Others.........................................
Section 6.04  Resignation of the Master Servicer...........................
Section 6.05  Compensation to the Master Servicer..........................
Section 6.06  Assignment or Delegation of Duties by Master Servicer........
Section 6.07  Indemnification of Trustee and Depositor by Master
               Servicer....................................................
Section 6.08  Master Servicer Errors and Omissions Policy..................


                                   ARTICLE VII

                                     DEFAULT

Section 7.01  Events of Default............................................
Section 7.02  Other Remedies of Trustee....................................
Section 7.03  Directions by Certificateholders and Duties of Trustee
               During Event of Default.....................................
Section 7.04  Action upon Certain Failures of the Master Servicer and
               upon Event of Default.......................................
Section 7.05  Trustee to Act; Appointment of Successor.....................
Section 7.06  Notification to Certificateholders...........................


                                  ARTICLE VIII

                             CONCERNING THE TRUSTEE

Section 8.01  Duties of Trustee............................................
Section 8.02  Certain Matters Affecting the Trustee........................
Section 8.03  Trustee Not Required to Make Investigation...................
Section 8.04  Trustee Not Liable for Certificates or Mortgage Loans........
Section 8.05  Trustee May Own Certificates.................................
Section 8.06  The Master Servicer to Pay Fees and Expenses; Limitation
               on Liability................................................
Section 8.07  Eligibility Requirements.....................................
Section 8.08  Resignation and Removal......................................
Section 8.09  Successor....................................................
Section 8.10  Merger or Consolidation......................................
Section 8.11  Authenticating Agent.........................................
Section 8.12  Separate Trustees and Co-Trustees............................
Section 8.13  Tax Matters; Compliance with REMIC Provisions................
Section 8.14  Monthly Advances.............................................


                                   ARTICLE IX

                                   TERMINATION

Section 9.01  Termination upon Purchase by the Depositor or Liquidation
               of All Mortgage Loans.......................................
Section 9.02  Additional Termination Requirements..........................


                                    ARTICLE X

                            MISCELLANEOUS PROVISIONS

Section 10.01 Amendment....................................................
Section 10.02 Recordation of Agreement.....................................
Section 10.03 Limitation on Rights of Certificateholders...................
Section 10.04 Governing Law; Jurisdiction..................................
Section 10.05 Notices......................................................
Section 10.06 Severability of Provisions...................................
Section 10.07 Special Notices to Rating Agencies...........................
Section 10.08 Covenant of Depositor........................................
Section 10.09 Recharacterization...........................................
Section 10.10 Regulation AB Compliance; Intent of Parties;
               Reasonableness..............................................


                                   ARTICLE XI

                             TERMS FOR CERTIFICATES

Section 11.01 Cut-Off Date.................................................
Section 11.02 Cut-Off Date Aggregate Principal Balance.....................
Section 11.03 Original Group I-A Percentage................................
Section 11.04 Original Group II-A Percentage...............................
Section 11.05 Original Principal Balances of the Classes of Class A
               Certificates................................................
Section 11.06 Original Notional Amount.....................................
Section 11.07 Original Group I-A and Group II-A Non-PO Principal
               Balances....................................................
Section 11.08 Original Subordinated Percentage.............................
Section 11.09 Original Group I Subordinated Principal Balance..............
Section 11.10 Original Group II Subordinated Principal Balance.............
Section 11.11 Original Principal Balances of the Classes of Class B
               Certificates................................................
Section 11.12 Original Class I-B-1 and Class II-B-1 Fractional Interest....
Section 11.13 Original Class I-B-2 and Class II-B-2 Fractional Interest....
Section 11.14 Original Class I-B-3 and Class II-B-3 Fractional Interest....
Section 11.15 Original Class I-B-4 and Class II-B-4 Fractional Interest....
Section 11.16 Original Class I-B-5 and Class II-B-5 Fractional Interest....
Section 11.17 Original Group I Class I-B-1 and Group II Class II-B-1
               Percentages.................................................
Section 11.18 Original Group I Class I-B-2 and Group II Class II-B-2
               Percentages.................................................
Section 11.19 Original Group I Class I-B-3 and Group II Class II-B-3
               Percentages.................................................
Section 11.20 Original Group I Class I-B-4 and Group II Class II-B-4
               Percentages.................................................
Section 11.21 Original Group I Class I-B-5 and Group II Class II-B-5
               Percentages.................................................
Section 11.22 Original Group I Class I-B-6 and Group II Class II-B-6
               Percentages.................................................
Section 11.23 Closing Date.................................................
Section 11.24 Right to Purchase............................................
Section 11.25 Wire Transfer Eligibility....................................
Section 11.26 Single Certificate...........................................
Section 11.27 Servicing Fee Rate...........................................
Section 11.28 Master Servicing Fee Rate....................................

SCHEDULE I      Applicable Unscheduled Principal Receipt Period
SCHEDULE II     Schedule for TAC Certificates

                                    EXHIBITS

EXHIBIT A-I-A-1         -     Form of Face of Class I-A-1 Certificate
EXHIBIT A-I-A-2         -     Form of Face of Class I-A-2 Certificate
EXHIBIT A-I-A-3         -     Form of Face of Class I-A-3 Certificate
EXHIBIT A-I-A-4         -     Form of Face of Class I-A-4 Certificate
EXHIBIT A-I-A-5         -     Form of Face of Class I-A-5 Certificate
EXHIBIT A-I-A-6         -     Form of Face of Class I-A-6 Certificate
EXHIBIT A-I-A-7         -     Form of Face of Class I-A-7 Certificate
EXHIBIT A-I-A-8         -     Form of Face of Class I-A-8 Certificate
EXHIBIT A-I-A-9         -     Form of Face of Class I-A-9 Certificate
EXHIBIT A-I-A-10        -     Form of Face of Class I-A-10 Certificate
EXHIBIT A-I-A-11        -     Form of Face of Class I-A-11 Certificate
EXHIBIT A-I-A-12        -     Form of Face of Class I-A-12 Certificate
EXHIBIT A-I-A-13        -     Form of Face of Class I-A-13 Certificate
EXHIBIT A-I-A-14        -     Form of Face of Class I-A-14 Certificate
EXHIBIT A-I-A-R         -     Form of Face of Class I-A-R Certificate
EXHIBIT A-I-A-PO        -     Form of Face of Class I-A-PO Certificate
EXHIBIT A-II-A-1        -     Form of Face of Class II-A-1 Certificate
EXHIBIT A-II-A-2        -     Form of Face of Class II-A-2 Certificate
EXHIBIT A-II-A-3        -     Form of Face of Class II-A-3 Certificate
EXHIBIT A-II-A-PO       -     Form of Face of Class II-A-PO Certificate
EXHIBIT I-B-1           -     Form of Face of Class I-B-1 Certificate
EXHIBIT I-B-2           -     Form of Face of Class I-B-2 Certificate
EXHIBIT I-B-3           -     Form of Face of Class I-B-3 Certificate
EXHIBIT I-B-4           -     Form of Face of Class I-B-4 Certificate
EXHIBIT I-B-5           -     Form of Face of Class I-B-5 Certificate
EXHIBIT I-B-6           -     Form of Face of Class I-B-6 Certificate
EXHIBIT II-B-1          -     Form of Face of Class II-B-1 Certificate
EXHIBIT II-B-2          -     Form of Face of Class II-B-2 Certificate
EXHIBIT II-B-3          -     Form of Face of Class II-B-3 Certificate
EXHIBIT II-B-4          -     Form of Face of Class II-B-4 Certificate
EXHIBIT II-B-5          -     Form of Face of Class II-B-5 Certificate
EXHIBIT II-B-6          -     Form of Face of Class II-B-6 Certificate
EXHIBIT C               -     Form of Reverse of Series 2006-4 Certificates
EXHIBIT D               -     Reserved
EXHIBIT E               -     Custodial Agreement
EXHIBIT F               -     Addresses for Requesting Mortgage Loan Schedule
EXHIBIT G               -     Request for Release
EXHIBIT H               -     Affidavit Pursuant to Section 860E(e)(4) of the
                              Internal Revenue Code of 1986, as amended, and
                              for Non-ERISA Investors
EXHIBIT I               -     Letter from Transferor of Residual Certificate
EXHIBIT J               -     Transferee's Letter (Class [I-B-4] [I-B-5]
                              [I-B-6] [II-B-4] [II-B-5] [II-B-6] Certificates)
EXHIBIT K               -     List of Recordation States
EXHIBIT L               -     Servicing Agreements
EXHIBIT M               -     Form of Special Servicing Agreement
EXHIBIT N               -     Form of Initial Certification of the Custodian
EXHIBIT O               -     Form of Final Certification of the Custodian
EXHIBIT P               -     Form of Sarbanes Oxley Certification
EXHIBIT Q               -     Schedule of Pledged Asset Mortgage Loans
EXHIBIT R               -     Servicing Criteria to be Addressed in
                              Assessment of Compliance
EXHIBIT S               -     Additional Form 10-D Disclosure
EXHIBIT T               -     Additional Form 10-K Disclosure
EXHIBIT U               -     Form 8-K Disclosure Information
EXHIBIT V               -     Additional Disclosure Notification
EXHIBIT W               -     Yield Maintenance Agreement

<PAGE>

            This Pooling and Servicing Agreement, dated as of March 30, 2006
executed by WELLS FARGO ASSET SECURITIES CORPORATION, as Depositor, WELLS FARGO
BANK, N.A., as Master Servicer and U.S. BANK NATIONAL ASSOCIATION, as Trustee.

                         W I T N E S S E T H  T H A T:

            In consideration of the mutual agreements herein contained, the
Depositor, the Master Servicer and the Trustee agree as follows:

                                    ARTICLE I

                                   DEFINITIONS

      Section 1.01 Definitions.

      Whenever used herein, the following words and phrases, unless the context
otherwise requires, shall have the meanings specified in this Article.

      1933 Act: The Securities Act of 1933, as amended.

      Accepted Master Servicing Practices: Accepted Master Servicing Practices
shall consist of the customary and usual master servicing practices of prudent
master servicing institutions which master service mortgage loans of the same
type as the Mortgage Loans in the jurisdictions in which the related Mortgaged
Properties are located, regardless of the date upon which the related Mortgage
Loans were originated.

      Accretion Termination Date: With respect to (a) the Class I-A-3 and Class
I-A-4 Certificates, the earlier to occur of (i) the Distribution Date following
the Distribution Date on which the Principal Balance of the Class I-A-2
Certificates has been reduced to zero or (ii) the Subordination Depletion Date
for Group I, (b) the Class I-A-7 Certificates, the earlier to occur of (i) the
Distribution Date following the Distribution Date on which the Principal Balance
of the Class I-A-5 Certificates has been reduced to zero or (ii) the
Subordination Depletion Date for Group I and (c) the Class I-A-10 Certificates,
the earlier to occur of (i) the Distribution Date following the Distribution
Date on which the Principal Balances of the Class I-A-5, Class I-A-7, Class
I-A-8 and Class I-A-9 Certificates have been reduced to zero or (ii) the
Subordination Depletion Date for Group I.

      Accrual Certificates: The Class I-A-3, Class I-A-4, Class I-A-7 and Class
I-A-10 Certificates.

      Accrual Distribution Amount: As to any Distribution Date prior to the
applicable Accretion Termination Date and a Class of Accrual Certificates, an
amount equal to the sum of (i) the Group I-A Interest Percentage of such Class
of Accrual Certificates of the Current Group I-A Interest Distribution Amount
and (ii) the Group I-A Interest Shortfall Percentage of such Class of Accrual
Certificates of the amount distributed in respect of the Classes of Group I-A
Certificates pursuant to Paragraph second clause (A) of Section 4.01(a)(i) on
such Distribution Date. As to any Distribution Date and a Class of Accrual
Certificates on or after the related Accretion Termination Date, zero.

      Additional Form 10-D Disclosure: As defined in Section 3.12(a).

      Additional Form 10-K Disclosure: As defined in Section 3.12(b).

      Additional Master Servicer: As defined in Section 6.06(b).

      Adjusted Principal Balance: As to any Distribution Date and any Class of
Class B Certificates of a Group, the greater of (A) zero and (B) (i) the
Principal Balance of such Class with respect to such Distribution Date minus
(ii) the applicable Adjustment Amount for such Distribution Date less the
Principal Balances for any Classes of Class B Certificates of such Group with
higher numerical designations.

      Adjustment Amount: For a Group for any Distribution Date, the difference
between (A) the sum of the Group I-A Non-PO Principal Balance or the Group II-A
Non-PO Principal Balance, as applicable, and the Group I-B Principal Balance or
the Group II-B Principal Balance, as applicable, as of the related Determination
Date and (B) the sum of (i) the sum of the Group I-A Non-PO Principal Balance or
the Group II-A Non-PO Principal Balance, as applicable, and the Group I-B
Principal Balance or the Group II-B Principal Balance, as applicable, as of the
Determination Date succeeding such Distribution Date and (ii) the aggregate
amount that would have been distributed to all Classes (other than the Class
A-PO Certificates) of such Group as principal in accordance with Section
4.01(a)(i) for such Distribution Date without regard to the provisos in the
definitions of (x) Class I-B-1 Optimal Principal Amount, Class I-B-2 Optimal
Principal Amount, Class I-B-3 Optimal Principal Amount, Class I-B-4 Optimal
Principal Amount, Class I-B-5 Optimal Principal Amount and Class I-B-6 Optimal
Principal Amount or (y) Class II-B-1 Optimal Principal Amount, Class II-B-2
Optimal Principal Amount, Class II-B-3 Optimal Principal Amount, Class II-B-4
Optimal Principal Amount, Class II-B-5 Optimal Principal Amount and Class II-B-6
Optimal Principal Amount, as applicable.

      Aggregate Group I-A Unpaid Interest Shortfall: As to any Distribution
Date, an amount equal to the sum of the Class A Unpaid Interest Shortfalls for
the Group I-A Certificates.

      Aggregate Group II-A Unpaid Interest Shortfall: As to any Distribution
Date, an amount equal to the sum of the Class A Unpaid Interest Shortfalls for
the Group II-A Certificates.

      Agreement: This Pooling and Servicing Agreement and all amendments and
supplements hereto.

      Applicable Unscheduled Principal Receipt Period: With respect to the
Mortgage Loans serviced by each Servicer and each of the Full Unscheduled
Principal Receipts and Partial Unscheduled Principal Receipts, the Unscheduled
Principal Receipt Period specified on Schedule I hereto, as amended by the
Master Servicer pursuant to Section 10.01(b) hereof.

      Authenticating Agent: Any authenticating agent appointed by the Trustee
pursuant to Section 8.11. Initially, the Master Servicer shall be the
Authenticating Agent for the Certificates.

      Available Master Servicer Compensation: For each Loan Group as to any
Distribution Date, the sum of (a) the Master Servicing Fee with respect to the
Mortgage Loans in such Loan Group for such Distribution Date, (b) interest
earned through the business day preceding the applicable Distribution Date on
any Prepayments in Full on the Mortgage Loans in such Loan Group remitted to the
Master Servicer and (c) the aggregate amount of Month End Interest with respect
to the Mortgage Loans in such Loan Group remitted by the Servicers to the Master
Servicer pursuant to the related Servicing Agreements.

      Bankruptcy Code: The Bankruptcy Code of 1978, as amended.

      Bankruptcy Loss: With respect to any Mortgage Loan, a Deficient Valuation
or Debt Service Reduction; provided, however, that a Bankruptcy Loss shall not
be deemed a Bankruptcy Loss hereunder so long as the applicable Servicer has
notified the Master Servicer and the Trustee in writing that such Servicer is
diligently pursuing any remedies that may exist in connection with the
representations and warranties made regarding the related Mortgage Loan and
either (A) the related Mortgage Loan is not in default with regard to payments
due thereunder or (B) delinquent payments of principal and interest under the
related Mortgage Loan and any premiums on any applicable primary hazard
insurance policy and any related escrow payments in respect of such Mortgage
Loan are being advanced on a current basis by such Servicer without giving
effect to any Debt Service Reduction.

      Beneficial Owner: With respect to a Book-Entry Certificate, the Person who
is the beneficial owner of such Book-Entry Certificate, as reflected on the
books of the Clearing Agency, or on the books of a Person maintaining an account
with such Clearing Agency (directly or as an indirect participant, in accordance
with the rules of such Clearing Agency), as the case may be.

      Book-Entry Certificate: Any one of the Class I-A-1 Certificates, Class
I-A-2 Certificates, Class I-A-3 Certificates, Class I-A-4 Certificates, Class
I-A-5 Certificates, Class I-A-6 Certificates, Class I-A-7 Certificates, Class
I-A-8 Certificates, Class I-A-9 Certificates, Class I-A-10 Certificates, Class
I-A-11 Certificates, Class I-A-12 Certificates, Class I-A-13 Certificates, Class
I-A-14 Certificates, Class I-A-PO Certificates, Class II-A-1 Certificates, Class
II-A-2 Certificates, Class II-A-3 Certificates, Class II-A-PO Certificates,
Class I-B-1 Certificates, Class I-B-2 Certificates, Class I-B-3 Certificates,
Class II-B-1 Certificates, Class II-B-2 Certificates and Class II-B-3
Certificates, beneficial ownership and transfers of which shall be evidenced by,
and made through, book entries by the Clearing Agency as described in Section
5.01(b).

      Business Day: Any day other than (i) a Saturday or a Sunday, or (ii) a
legal holiday in the City of New York, State of Iowa, State of Maryland, State
of Minnesota or State of North Carolina or (iii) a day on which banking
institutions in the City of New York, or the State of Iowa, State of Maryland,
State of Minnesota or State of North Carolina are authorized or obligated by law
or executive order to be closed.

      Certificate: Any one of the Class A Certificates or Class B Certificates.

      Certificate Account: The separate trust account established and maintained
by the Master Servicer in the name of the Master Servicer on behalf of the
Trustee pursuant to Section 3.01. The Certificate Account shall be an Eligible
Account.

      Certificate Custodian: Initially, Wells Fargo Bank; thereafter any other
Certificate Custodian acceptable to The Depository Trust Company and selected by
the Trustee.

      Certificate Register and Certificate Registrar: Respectively, the register
maintained pursuant to and the registrar provided for in Section 5.02. Initially
the Certificate Registrar shall be the Master Servicer.

      Certificateholder or Holder: The Person in whose name a Certificate is
registered in the Certificate Register, except that, solely for the purposes of
the taking of any action under Articles VII or VIII, any Certificate registered
in the name of the Master Servicer, a Servicer or any affiliate thereof shall be
deemed not to be outstanding and the Voting Interest evidenced thereby shall not
be taken into account in determining whether the requisite percentage of
Certificates necessary to effect any such action has been obtained.

      Class: All certificates whose form is identical except for variations in
the Percentage Interest evidenced thereby.

      Class I-A-1 Certificate: Any one of the Certificates executed by the
Paying Agent and countersigned by the Authenticating Agent in substantially the
form set forth in Exhibit A-I-A-1 and Exhibit C hereto.

      Class I-A-1 Certificateholder: The registered holder of a Class I-A-1
Certificate.

      Class I-A-2 Certificate: Any one of the Certificates executed by the
Paying Agent and countersigned by the Authenticating Agent in substantially the
form set forth in Exhibit A-I-A-2 and Exhibit C hereto.

      Class I-A-2 Certificateholder: The registered holder of a Class I-A-2
Certificate.

      Class I-A-2 Loss Amount: With respect to any Determination Date after the
applicable Subordination Depletion Date, the amount, if any, by which the
Principal Balance of the Class I-A-2 Certificates would be reduced as a result
of the application of the third sentence of the definition of Principal Balance.

      Class I-A-3 Certificate: Any one of the Certificates executed by the
Paying Agent and countersigned by the Authenticating Agent in substantially the
form set forth in Exhibit A-I-A-3 and Exhibit C hereto.

      Class I-A-3 Certificateholder: The registered holder of a Class I-A-3
Certificate.

      Class I-A-3 Loss Amount: With respect to any Determination Date after the
applicable Subordination Depletion Date, the amount, if any, by which the
Principal Balance of the Class I-A-3 Certificates would be reduced as a result
of the application of the third sentence of the definition of Principal Balance.

      Class I-A-4 Certificate: Any one of the Certificates executed by the
Paying Agent and countersigned by the Authenticating Agent in substantially the
form set forth in Exhibit A-I-A-4 and Exhibit C hereto.

      Class I-A-4 Certificateholder: The registered holder of a Class I-A-4
Certificate.

      Class I-A-4 Loss Allocation Amount: With respect to any Determination Date
after the applicable Subordination Depletion Date the lesser of (a) the
Principal Balance of the Class I-A-4 Certificates with respect to such
Determination Date prior to any reduction for the Class I-A-4 Loss Allocation
Amount and (b) the Class I-A-3 Loss Amount.

      Class I-A-5 Certificate: Any one of the Certificates executed by the
Paying Agent and countersigned by the Authenticating Agent in substantially the
form set forth in Exhibit A-I-A-5 and Exhibit C hereto.

      Class I-A-5 Certificateholder: The registered holder of a Class I-A-5
Certificate.

      Class I-A-5 Loss Amount: With respect to any Determination Date after the
applicable Subordination Depletion Date, the amount, if any, by which the
Principal Balance of the Class I-A-5 Certificates would be reduced as a result
of the application of the third sentence of the definition of Principal Balance.

      Class I-A-5 Pass-Through Rate: With respect to the Distribution Date
occurring in April 2006, 5.420% per annum. With respect to each succeeding
Distribution Date, a per annum rate, determined by the Paying Agent on the
applicable Rate Determination Date, equal to LIBOR plus 0.700%, subject to a
minimum rate of 0.700% and a maximum rate of 5.750%.

      Class I-A-6 Certificate: Any one of the Certificates executed by the
Paying Agent and countersigned by the Authenticating Agent in substantially the
form set forth in Exhibit A-I-A-6 and Exhibit C hereto.

      Class I-A-6 Certificateholder: The registered holder of a Class I-A-6
Certificate.

      Class I-A-6 Notional Amount: As to any Distribution Date, an amount equal
to the Principal Balance of the Class I-A-5 Certificates.

      Class I-A-6 Pass-Through Rate: With respect to the Distribution Date
occurring in April 2006, 0.330% per annum. With respect to each succeeding
Distribution Date, a per annum rate, determined by the Paying Agent on the
applicable Rate Determination Date, equal to 5.050% minus LIBOR, subject to a
minimum rate of 0.000% and a maximum rate of 5.050%.

      Class I-A-7 Certificate: Any one of the Certificates executed by the
Paying Agent and countersigned by the Authenticating Agent in substantially the
form set forth in Exhibit A-I-A-7 and Exhibit C hereto.

      Class I-A-7 Certificateholder: The registered holder of a Class I-A-7
Certificate.

      Class I-A-8 Certificate: Any one of the Certificates executed by the
Paying Agent and countersigned by the Authenticating Agent in substantially the
form set forth in Exhibit A-I-A-8 and Exhibit C hereto.

      Class I-A-8 Certificateholder: The registered holder of a Class I-A-8
Certificate.

      Class I-A-9 Certificate: Any one of the Certificates executed by the
Paying Agent and countersigned by the Authenticating Agent in substantially the
form set forth in Exhibit A-I-A-9 and Exhibit C hereto.

      Class I-A-9 Certificateholder: The registered holder of a Class I-A-9
Certificate.

      Class I-A-10 Certificate: Any one of the Certificates executed by the
Paying Agent and countersigned by the Authenticating Agent in substantially the
form set forth in Exhibit A-I-A-10 and Exhibit C hereto.

      Class I-A-10 Certificateholder: The registered holder of a Class I-A-10
Certificate.

      Class I-A-11 Certificate: Any one of the Certificates executed by the
Paying Agent and countersigned by the Authenticating Agent in substantially the
form set forth in Exhibit A-I-A-11 and Exhibit C hereto.

      Class I-A-11 Certificateholder: The registered holder of a Class I-A-11
Certificate.

      Class I-A-12 Certificate: Any one of the Certificates executed by the
Paying Agent and countersigned by the Authenticating Agent in substantially the
form set forth in Exhibit A-I-A-12 and Exhibit C hereto.

      Class I-A-12 Certificateholder: The registered holder of a Class I-A-12
Certificate.

      Class I-A-12 Loss Amount: With respect to any Determination Date after the
applicable Subordination Depletion Date, the amount, if any, by which the
Principal Balance of the Class I-A-12 Certificates would be reduced as a result
of the application of the third sentence of the definition of Principal Balance.

      Class I-A-13 Certificate: Any one of the Certificates executed by the
Paying Agent and countersigned by the Authenticating Agent in substantially the
form set forth in Exhibit A-I-A-13 and Exhibit C hereto.

      Class I-A-13 Certificateholder: The registered holder of a Class I-A-13
Certificate.

      Class I-A-13 Loss Allocation Amount: With respect to any Determination
Date after the applicable Subordination Depletion Date, the lesser of (a) the
Principal Balance of the Class I-A-13 Certificates with respect to such
Determination Date prior to any reduction for the Class I-A-13 Loss Allocation
Amount and (b) the sum of the Class I-A-2 Loss Amount, Class I-A-5 Loss Amount
and Class I-A-12 Loss Amount.

      Class I-A-14 Certificate: Any one of the Certificates executed by the
Paying Agent and countersigned by the Authenticating Agent in substantially the
form set forth in Exhibit A-I-A-14 and Exhibit C hereto.

      Class I-A-14 Certificateholder: The registered holder of a Class I-A-14
Certificate.

      Class I-A-LR Interest: The residual interest in the Lower-Tier REMIC,
beneficial ownership of which is represented by the Class I-A-R Certificate.

      Class I-A-PO Certificate: Any one of the Certificates executed by the
Paying Agent and countersigned by the Authenticating Agent in substantially the
form set forth in Exhibit A-I-A-PO and Exhibit C hereto.

      Class I-A-PO Certificateholder: The registered holder of a Class I-A-PO
Certificate.

      Class I-A-PO Deferred Amount: For any Distribution Date prior to the
applicable Subordination Depletion Date, the difference between (A) the sum of
(x) the amount by which the sum of the Class I-A-PO Optimal Principal Amounts
for the Class I-A-PO Certificates for all prior Distribution Dates exceeded the
amounts distributed on the Class I-A-PO Certificates on such prior Distribution
Dates pursuant to Paragraph third clause (A) of Section 4.01(a)(i) and (y) the
sum of the product for each Group I Discount Mortgage Loan which became a
Liquidated Loan at any time on or prior to the last day of the Applicable
Unscheduled Principal Receipt Period for Full Unscheduled Principal Receipts for
the current Distribution Date of (a) the PO Fraction for such Group I Discount
Mortgage Loan and (b) an amount equal to the principal portion of Realized
Losses (other than Bankruptcy Losses due to Debt Service Reductions) incurred
with respect to such Mortgage Loan and (B) the sum of (x) the sum of the Class
I-A-PO Recoveries for such Distribution Date and prior Distribution Dates and
(y) amounts distributed on the Class I-A-PO Certificates on prior Distribution
Dates pursuant to Paragraph fourth clause (A) of Section 4.01(a)(i). On and
after the applicable Subordination Depletion Date, the Class I-A-PO Deferred
Amount will be zero. No interest will accrue on any Class I-A-PO Deferred
Amount.

      Class I-A-PO Optimal Principal Amount: As to any Distribution Date, an
amount equal to the sum of (I) the sum, as to each Group I Mortgage Loan that is
an Outstanding Mortgage Loan, of the product of (x) the PO Fraction with respect
to such Group I Mortgage Loan and (y) the sum of:

            (i) the principal portion of the Monthly Payment due on the Due Date
      occurring in the month of such Distribution Date on such Group I Mortgage
      Loan;

            (ii) all Unscheduled Principal Receipts (other than Recoveries) that
      were received by a Servicer with respect to such Group I Mortgage Loan
      during the Applicable Unscheduled Principal Receipt Period relating to
      such Distribution Date for each applicable type of Unscheduled Principal
      Receipt;

            (iii) the Scheduled Principal Balance of each Group I Mortgage Loan
      which, during the one month period ending on the day preceding the
      Determination Date for such Distribution Date, was repurchased by the
      Depositor pursuant to Section 2.02, 2.03 or 3.08; and

            (iv) the Substitution Principal Amount with respect to each Group I
      Mortgage Loan for which a Group I Mortgage Loan was substituted during the
      one month period ending on the day preceding the Determination Date for
      such Distribution Date, less the amount allocable to the principal portion
      of any unreimbursed Periodic Advances previously made by the applicable
      Servicer, the Master Servicer or the Trustee in respect of such Group I
      Mortgage Loan for which a Group I Mortgage Loan was substituted; and

      (II) the Class I-A-PO Recovery for such Distribution Date.

      Class I-A-PO Recovery: As to any Distribution Date prior to the applicable
Subordination Depletion Date, the lesser of (a) the Class I-A-PO Deferred Amount
for such Distribution Date (calculated without regard to the Class I-A-PO
Recovery for such Distribution Date) and (b) an amount equal to the sum as to
each Group I Mortgage Loan as to which there has been a Recovery during the
Applicable Unscheduled Principal Receipt Period, of the product of (x) the PO
Fraction with respect to such Group I Mortgage Loan and (y) the amount of the
Recovery with respect to such Group I Mortgage Loan. As to any Distribution Date
on or after the applicable Subordination Depletion Date, the amount determined
in accordance with clause (b) above.

      Class I-A-R Certificate: The Certificate executed by the Paying Agent and
countersigned by the Authenticating Agent in substantially the form set forth in
Exhibit A-I-A-R and Exhibit C hereto.

      Class I-A-R Certificateholder: The registered holder of the Class I-A-R
Certificate.

      Class I-A-R Interest: The residual interest in the Upper-Tier REMIC,
beneficial ownership of which is evidenced by the Class I-A-R Certificate.

      Class II-A-1 Certificate: Any one of the Certificates executed by the
Paying Agent and countersigned by the Authenticating Agent in substantially the
form set forth in Exhibit A-II-A-1 and Exhibit C hereto.

      Class II-A-1 Certificateholder: The registered holder of a Class II-A-1
Certificate.

      Class II-A-1 Loss Amount: With respect to any Determination Date after the
applicable Subordination Depletion Date, the amount, if any, by which the
Principal Balance of the Class II-A-1 Certificates would be reduced as a result
of the application of the third sentence of the definition of Principal Balance.

      Class II-A-2 Certificate: Any one of the Certificates executed by the
Paying Agent and countersigned by the Authenticating Agent in substantially the
form set forth in Exhibit A-II-A-2 and Exhibit C hereto.

      Class II-A-2 Certificateholder: The registered holder of a Class II-A-2
Certificate.

      Class II-A-2 Loss Amount: With respect to any Determination Date after the
applicable Subordination Depletion Date, the amount, if any, by which the
Principal Balance of the Class II-A-2 Certificates would be reduced as a result
of the application of the third sentence of the definition of Principal Balance.

      Class II-A-3 Certificate: Any one of the Certificates executed by the
Paying Agent and countersigned by the Authenticating Agent in substantially the
form set forth in Exhibit A-II-A-3 and Exhibit C hereto.

      Class II-A-3 Certificateholder: The registered holder of a Class II-A-3
Certificate.

      Class II-A-3 Loss Allocation Amount: With respect to any Determination
Date after the applicable Subordination Depletion Date, the lesser of (a) the
Principal Balance of the Class II-A-3 Certificates with respect to such
Determination Date prior to any reduction for the Class II-A-3 Loss Allocation
Amount and (b) the sum of the Class II-A-1 Loss Amount and Class II-A-2 Loss
Amount.

      Class II-A-PO Certificate: Any one of the Certificates executed by the
Paying Agent and countersigned by the Authenticating Agent in substantially the
form set forth in Exhibit A-II-A-PO and Exhibit C hereto.

      Class II-A-PO Certificateholder: The registered holder of a Class II-A-PO
Certificate.

      Class II-A-PO Deferred Amount: For any Distribution Date prior to the
applicable Subordination Depletion Date, the difference between (A) the sum of
(x) the amount by which the sum of the Class II-A-PO Optimal Principal Amounts
for the Class II-A-PO Certificates for all prior Distribution Dates exceeded the
amounts distributed on the Class II-A-PO Certificates on such prior Distribution
Dates pursuant to Paragraph third clause (B) of Section 4.01 (a)(i) and (y) the
sum of the product for each Group II Discount Mortgage Loan which became a
Liquidated Loan at any time on or prior to the last day of the Applicable
Unscheduled Principal Receipt Period for Full Unscheduled Principal Receipts for
the current Distribution Date of (a) the PO Fraction for such Group II Discount
Mortgage Loan and (b) an amount equal to the principal portion of Realized
Losses (other than Bankruptcy Losses due to Debt Service Reductions) incurred
with respect to such Mortgage Loan and (B) the sum of (x) the sum of the Class
II-A-PO Recoveries for such Distribution Date and prior Distribution Dates and
(y) amounts distributed on the Class II-A-PO Certificates on prior Distribution
Dates pursuant to Paragraph fourth clause (B) of Section 4.0l(a)(i). On and
after the applicable Subordination Depletion Date, the Class II-A-PO Deferred
Amount will be zero. No interest will accrue on any Class II-A-PO Deferred
Amount.

      Class II-A-PO Optimal Principal Amount: As to any Distribution Date, an
amount equal to the sum of (I) the sum of, as to each Group II Mortgage Loan
that is an Outstanding Mortgage Loan, of the product of (x) the PO Fraction with
respect to such Group II Mortgage Loan and (y) the sum of:

            (i) the principal portion of the Monthly Payment due on the Due Date
      occurring in the month of such Distribution Date on such Group II Mortgage
      Loan;

            (ii) all Unscheduled Principal Receipts (other than Recoveries) that
      were received by a Servicer with respect to such Group II Mortgage Loan
      during the Applicable Unscheduled Principal Receipt Period relating to
      such Distribution Date for each applicable type of Unscheduled Principal
      Receipt;

            (iii) the Scheduled Principal Balance of each Group II Mortgage Loan
      which, during the one month period ending on the day preceding the
      Determination Date for such Distribution Date, was repurchased by the
      Depositor pursuant to Section 2.02, 2.03 or 3.08; and

            (iv) the Substitution Principal Amount with respect to each Group II
      Mortgage Loan for which a Group II Mortgage Loan was substituted during
      the one month period ending on the day preceding the Determination Date
      for such Distribution Date, less the amount allocable to the principal
      portion of any unreimbursed Periodic Advances previously made by the
      applicable Servicer, the Master Servicer or the Trustee in respect of such
      Group II Mortgage Loan for which a Group II Mortgage Loan was substituted;
      and

      (II) the Class II-A-PO Recovery for such Distribution Date.

      Class II-A-PO Recovery: As to any Distribution Date prior to the
applicable Subordination Depletion Date, the lesser of (a) the Class II-A-PO
Deferred Amount for such Distribution Date (calculated without regard to the
Class II-A-PO Recovery for such Distribution Date) and (b) an amount equal to
the sum as to each Group II Mortgage Loan as to which there has been a Recovery
during the Applicable Unscheduled Principal Receipt Period, of the product of
(x) the PO Fraction with respect to such Group II Mortgage Loan and (y) the
amount of the Recovery with respect to such Group II Mortgage Loan. As to any
Distribution Date on or after the applicable Subordination Depletion Date, the
amount determined in accordance with clause (b) above.

      Class A Certificate: Any of the Group I-A Certificates or Group II-A
Certificates.

      Class A Certificateholder: The registered holder of a Class A Certificate.

      Class A Pass-Through Rate: As to the Class I-A-1, Class I-A-2, Class
I-A-3, Class I-A-4, Class I-A-7, Class I-A-8, Class I-A-9, Class I-A-10, Class
I-A-11, Class I-A-12, Class I-A-13, Class I-A-14, Class I-A-R and Class II-A-3
Certificates, 5.750% per annum. As to the Class II-A-1 Certificates, 6.000% per
annum. As to the Class II-A-2 Certificates, 5.500% per annum. As to the Class
I-A-5 and Class I-A-6 Certificates, the Class I-A-5 Pass-Through Rate and Class
I-A-6 Pass-Through Rate, respectively. The Class I-A-PO and Class II-A-PO
Certificates are not entitled to interest and do not have Class A Pass-Through
Rates.

      Class A-PO Certificates: Either of the Class I-A-PO Certificates or Class
II-A-PO Certificates.

      Class A-PO Deferred Amount: Either of the Class I-A-PO Deferred Amount or
Class II-A-PO Deferred Amount.

      Class A Unpaid Interest Shortfall: For a Group, as to any Distribution
Date and any Class of Class A Certificates of such Group, the amount, if any, by
which the aggregate of the Group I-A Interest Shortfall Amounts or Group II-A
Interest Shortfall Amounts, as applicable, for such Class (or in the case of a
Class of Accrual Certificates prior to the applicable Accretion Termination
Date, the amount included in the Accrual Distribution Amount pursuant to clause
(ii) of the definition thereof) for prior Distribution Dates is in excess of the
amounts distributed in respect of such Class on prior Distribution Dates
pursuant to Paragraph second clause (A) or (B), as applicable, of Section
4.01(a)(i).

      Class I-B-1 Certificate: Any one of the Certificates executed by the
Paying Agent and countersigned by the Authenticating Agent in substantially the
form set forth in Exhibit I-B-1 and Exhibit C hereto.

      Class I-B-1 Certificateholder: The registered holder of a Class I-B-1
Certificate.

      Class I-B-1 Distribution Amount: As to any Distribution Date, any amount
distributable to the Holders of the Class I-B-1 Certificates pursuant to
Paragraphs fifth clause (A), sixth clause (A) and seventh clause (A) of Section
4.01(a)(i).

      Class I-B-1 Interest Shortfall Amount: As to any Distribution Date, any
amount by which the Interest Accrual Amount of the Class I-B-1 Certificates with
respect to such Distribution Date exceeds the amount distributed in respect of
the Class I-B-1 Certificates on such Distribution Date pursuant to Paragraph
fifth clause (A) of Section 4.01(a)(i).

      Class I-B-1 Optimal Principal Amount: As to any Distribution Date, an
amount equal to the sum of (I) the sum, as to each Group I Mortgage Loan that is
an Outstanding Mortgage Loan, of the product of (x) the Non-PO Fraction with
respect to such Group I Mortgage Loan and (y) the sum of:

            (i) the Group I Class I-B-1 Percentage of the principal portion of
      the Monthly Payment due on the Due Date occurring in the month of such
      Distribution Date on such Mortgage Loan;

            (ii) the Group I Class I-B-1 Prepayment Percentage (with respect to
      each such Group I Mortgage Loan) of all Unscheduled Principal Receipts
      (other than Recoveries) that were received by a Servicer with respect to
      such Group I Mortgage Loan during the Applicable Unscheduled Principal
      Receipt Period relating to such Distribution Date for each applicable type
      of Unscheduled Principal Receipt;

            (iii) the Group I Class I-B-1 Prepayment Percentage of the Scheduled
      Principal Balance of such Mortgage Loan which, during the one month period
      ending on the day preceding the Determination Date for such Distribution
      Date, was repurchased by the Depositor pursuant to Section 2.02, 2.03 or
      3.08; and

            (iv) the Group I Class I-B-1 Percentage of the Substitution
      Principal Amount with respect to each Group I Mortgage Loan for which a
      Group I Mortgage Loan was substituted during the one month period ending
      on the day preceding the Determination Date for such Distribution Date,
      less the amount allocable to the principal portion of any unreimbursed
      Periodic Advances previously made by the applicable Servicer, the Master
      Servicer or the Trustee in respect of such Group I Mortgage Loan for which
      a Group I Mortgage Loan was substituted; and

      (II) the Group I Class I-B-1 Prepayment Percentage of the Non-PO Recovery
      for such Loan Group for such Distribution Date;

provided, however, that if an Optimal Adjustment Event occurs with respect to
such Class and such Distribution Date, the Class I-B-1 Optimal Principal Amount
will equal the lesser of (A) the Class I-B-1 Optimal Principal Amount calculated
as described in the preceding provisions and (B) the Adjusted Principal Balance
for the Class I-B-1 Certificates.

      Class I-B-1 Principal Balance: As to the first Determination Date, the
Original Class I-B-1 Principal Balance. As of any subsequent Determination Date,
the Original Class I-B-1 Principal Balance less the sum of all amounts
previously distributed in respect of the Class I-B-1 Certificates on prior
Distribution Dates (A) pursuant to Paragraph seventh clause (A) of Section
4.01(a)(i) (including any principal otherwise payable to the Class I-B-1
Certificates used to pay any Class I-A-PO Deferred Amounts) and (B) as a result
of a Principal Adjustment; provided, however, if the Class I-B-1 Certificates
are the most subordinate Group I-B Certificates outstanding, the Class I-B-1
Principal Balance will equal the difference, if any, between the Group I
Adjusted Pool Amount (Non-PO Portion) as of the preceding Distribution Date less
the Group I-A Non-PO Principal Balance as of such Determination Date.

      Class I-B-1 Principal Distribution Amount: As to any Distribution Date,
any amount distributable to the Holders of the Class I-B-1 Certificates pursuant
to Paragraph seventh clause (A) of Section 4.01(a)(i).

      Class I-B-1 Unpaid Interest Shortfall: As to any Distribution Date, the
amount, if any, by which the aggregate of the Class I-B-1 Interest Shortfall
Amounts for prior Distribution Dates is in excess of the amounts distributed in
respect of the Class I-B-1 Certificates on prior Distribution Dates pursuant to
Paragraph sixth clause (A) of Section 4.01(a)(i).

      Class I-B-2 Certificate: Any one of the Certificates executed by the
Paying Agent and countersigned by the Authenticating Agent in substantially the
form set forth in Exhibit I-B-2 and Exhibit C hereto.

      Class I-B-2 Certificateholder: The registered holder of a Class I-B-2
Certificate.

      Class I-B-2 Distribution Amount: As to any Distribution Date, any amount
distributable to the Holders of the Class I-B-2 Certificates pursuant to
Paragraphs eighth clause (A), ninth clause (A) and tenth clause (A) of Section
4.01(a)( i).

      Class I-B-2 Interest Shortfall Amount: As to any Distribution Date, any
amount by which the Interest Accrual Amount of the Class I-B-2 Certificates with
respect to such Distribution Date exceeds the amount distributed in respect of
the Class I-B-2 Certificates on such Distribution Date pursuant to Paragraph
eighth clause (A) of Section 4.01(a)(i).

      Class I-B-2 Optimal Principal Amount: As to any Distribution Date, an
amount equal to the sum of (I) the sum, as to each Group I Mortgage Loan that is
an Outstanding Mortgage Loan, of the product of (x) the Non-PO Fraction with
respect to such Group I Mortgage Loan and (y) the sum of:

            (i) the Group I Class I-B-2 Percentage of the principal portion of
      the Monthly Payment due on the Due Date occurring in the month of such
      Distribution Date on such Mortgage Loan;

            (ii) the Group I Class I-B-2 Prepayment Percentage (with respect to
      each such Group I Mortgage Loan) of all Unscheduled Principal Receipts
      (other than Recoveries) that were received by a Servicer with respect to
      such Group I Mortgage Loan during the Applicable Unscheduled Principal
      Receipt Period relating to such Distribution Date for each applicable type
      of Unscheduled Principal Receipt;

            (iii) the Group I Class I-B-2 Prepayment Percentage of the Scheduled
      Principal Balance of such Mortgage Loan which, during the one month period
      ending on the day preceding the Determination Date for such Distribution
      Date, was repurchased by the Depositor pursuant to Section 2.02, 2.03 or
      3.08; and

            (iv) the Group I Class I-B-2 Percentage of the Substitution
      Principal Amount with respect to each Group I Mortgage Loan for which a
      Group I Mortgage Loan was substituted during the one month period ending
      on the day preceding the Determination Date for such Distribution Date,
      less the amount allocable to the principal portion of any unreimbursed
      Periodic Advances previously made by the applicable Servicer, the Master
      Servicer or the Trustee in respect of such Group I Mortgage Loan for which
      a Group I Mortgage Loan was substituted; and

      (II) the Group I Class I-B-2 Prepayment Percentage of the Non-PO Recovery
      for such Loan Group for such Distribution Date;

provided, however, that if an Optimal Adjustment Event occurs with respect to
such Class and such Distribution Date, the Class I-B-2 Optimal Principal Amount
will equal the lesser of (A) the Class I-B-2 Optimal Principal Amount calculated
as described in the preceding provisions and (B) the Adjusted Principal Balance
for the Class I-B-2 Certificates.

      Class I-B-2 Principal Balance: As to the first Determination Date, the
Original Class I-B-2 Principal Balance. As of any subsequent Determination Date,
the Original Class I-B-2 Principal Balance less the sum of all amounts
previously distributed in respect of the Class I-B-2 Certificates on prior
Distribution Dates (A) pursuant to Paragraph tenth clause (A) of Section
4.01(a)(i) (including any principal otherwise payable to the Class I-B-2
Certificates used to pay any Class I-A-PO Deferred Amounts) and (B) as a result
of a Principal Adjustment; provided, however, if the Class I-B-2 Certificates
are the most subordinate Group I-B Certificates outstanding, the Class I-B-2
Principal Balance will equal the difference, if any, between the Group I
Adjusted Pool Amount (Non-PO Portion) as of the preceding Distribution Date less
the sum of the Group I-A (Non-PO Portion) Principal Balance and the Class I-B-1
Principal Balance as of such Determination Date.

      Class I-B-2 Principal Distribution Amount: As to any Distribution Date,
any amount distributable to the Holders of the Class I-B-2 Certificates pursuant
to Paragraph tenth clause (A) of Section 4.01(a)(i).

      Class I-B-2 Unpaid Interest Shortfall: As to any Distribution Date, the
amount, if any, by which the aggregate of the Class I-B-2 Interest Shortfall
Amounts for prior Distribution Dates is in excess of the amounts distributed in
respect of the Class I-B-2 Certificates on prior Distribution Dates pursuant to
Paragraph ninth clause (A) of Section 4.01(a)(i).

      Class I-B-3 Certificate: Any one of the Certificates executed by the
Paying Agent and countersigned by the Authenticating Agent in substantially the
form set forth in Exhibit I-B-3 and Exhibit C hereto.

      Class I-B-3 Certificateholder: The registered holder of a Class I-B-3
Certificate.

      Class I-B-3 Distribution Amount: As to any Distribution Date, any amount
distributable to the Holders of the Class I-B-3 Certificates pursuant to
Paragraphs eleventh clause (A), twelfth clause (A) and thirteenth clause (A) of
Section 4.01(a)(i).

      Class I-B-3 Interest Shortfall Amount: As to any Distribution Date, any
amount by which the Interest Accrual Amount of the Class I-B-3 Certificates with
respect to such Distribution Date exceeds the amount distributed in respect of
the Class I-B-3 Certificates on such Distribution Date pursuant to Paragraph
eleventh clause (A) of Section 4.01(a)(i).

      Class I-B-3 Optimal Principal Amount: As to any Distribution Date, an
amount equal to the sum of (I) the sum, as to each Group I Mortgage Loan that is
an Outstanding Mortgage Loan, of the product of (x) the Non-PO Fraction with
respect to such Group I Mortgage Loan and (y) the sum of:

            (i) the Group I Class I-B-3 Percentage of the principal portion of
      the Monthly Payment due on the Due Date occurring in the month of such
      Distribution Date on such Mortgage Loan;

            (ii) the Group I Class I-B-3 Prepayment Percentage (with respect to
      each such Group I Mortgage Loan) of all Unscheduled Principal Receipts
      (other than Recoveries) that were received by a Servicer with respect to
      such Group I Mortgage Loan during the Applicable Unscheduled Principal
      Receipt Period relating to such Distribution Date for each applicable type
      of Unscheduled Principal Receipt;

            (iii) the Group I Class I-B-3 Prepayment Percentage of the Scheduled
      Principal Balance of such Mortgage Loan which, during the one month period
      ending on the day preceding the Determination Date for such Distribution
      Date, was repurchased by the Depositor pursuant to Section 2.02, 2.03 or
      3.08; and

            (iv) the Group I Class I-B-3 Percentage of the Substitution
      Principal Amount with respect to each Group I Mortgage Loan for which a
      Group I Mortgage Loan was substituted during the one month period ending
      on the day preceding the Determination Date for such Distribution Date,
      less the amount allocable to the principal portion of any unreimbursed
      Periodic Advances previously made by the applicable Servicer, the Master
      Servicer or the Trustee in respect of such Group I Mortgage Loan for which
      a Group I Mortgage Loan was substituted; and

      (II) the Group I Class I-B-3 Prepayment Percentage of the Non-PO Recovery
      for such Loan Group for such Distribution Date;

provided, however, that if an Optimal Adjustment Event occurs with respect to
such Class and such Distribution Date, the Class I-B-3 Optimal Principal Amount
will equal the lesser of (A) the Class I-B-3 Optimal Principal Amount calculated
as described in the preceding provisions and (B) the Adjusted Principal Balance
for the Class I-B-3 Certificates.

      Class I-B-3 Principal Balance: As to the first Determination Date, the
Original Class I-B-3 Principal Balance. As of any subsequent Determination Date,
the Original Class I-B-3 Principal Balance less the sum of all amounts
previously distributed in respect of the Class I-B-3 Certificates on prior
Distribution Dates (A) pursuant to Paragraph thirteenth clause (A) of Section
4.01(a)(i) (including any principal otherwise payable to the Class I-B-3
Certificates used to pay any Class I-A-PO Deferred Amounts) and (B) as a result
of a Principal Adjustment; provided, however, if the Class I-B-3 Certificates
are the most subordinate Group I-B Certificates outstanding, the Class I-B-3
Principal Balance will equal the difference, if any, between the Group I
Adjusted Pool Amount (Non-PO Portion) as of the preceding Distribution Date less
the sum of the Group I-A Non-PO Principal Balance, the Class I-B-1 Principal
Balance and the Class I-B-2 Principal Balance as of such Determination Date.

      Class I-B-3 Principal Distribution Amount: As to any Distribution Date,
any amount distributable to the Holders of the Class I-B-3 Certificates pursuant
to Paragraph thirteenth clause (A) of Section 4.01(a)(i).

      Class I-B-3 Unpaid Interest Shortfall: As to any Distribution Date, the
amount, if any, by which the aggregate of the Class I-B-3 Interest Shortfall
Amounts for prior Distribution Dates is in excess of the amounts distributed in
respect of the Class I-B-3 Certificates on prior Distribution Dates pursuant to
Paragraph twelfth clause (A) of Section 4.01(a)(i).

      Class I-B-4 Certificate: Any one of the Certificates executed by the
Paying Agent and countersigned by the Authenticating Agent in substantially the
form set forth in Exhibit I-B-4 and Exhibit C hereto.

      Class I-B-4 Certificateholder: The registered holder of a Class I-B-4
Certificate.

      Class I-B-4 Distribution Amount: As to any Distribution Date, any amount
distributable to the Holders of the Class I-B-4 Certificates pursuant to
Paragraphs fourteenth clause (A), fifteenth clause (A) and sixteenth clause (A)
of Section 4.01(a)(i).

      Class I-B-4 Interest Shortfall Amount: As to any Distribution Date, any
amount by which the Interest Accrual Amount of the Class I-B-4 Certificates with
respect to such Distribution Date exceeds the amount distributed in respect of
the Class I-B-4 Certificates on such Distribution Date pursuant to Paragraph
fourteenth clause (A) of Section 4.01(a)(i).

      Class I-B-4 Optimal Principal Amount: As to any Distribution Date, an
amount equal to the sum of (I) the sum, as to each Group I Mortgage Loan that is
an Outstanding Mortgage Loan, of the product of (x) the Non-PO Fraction with
respect to such Group I Mortgage Loan and (y) the sum of:

            (i) the Group I Class I-B-4 Percentage of the principal portion of
      the Monthly Payment due on the Due Date occurring in the month of such
      Distribution Date on such Mortgage Loan;

            (ii) the Group I Class I-B-4 Prepayment Percentage (with respect to
      each such Group I Mortgage Loan) of all Unscheduled Principal Receipts
      (other than Recoveries) that were received by a Servicer with respect to
      such Group I Mortgage Loan during the Applicable Unscheduled Principal
      Receipt Period relating to such Distribution Date for each applicable type
      of Unscheduled Principal Receipt;

            (iii) the Group I Class I-B-4 Prepayment Percentage of the Scheduled
      Principal Balance of such Mortgage Loan which, during the one month period
      ending on the day preceding the Determination Date for such Distribution
      Date, was repurchased by the Depositor pursuant to Section 2.02, 2.03 or
      3.08; and

            (iv) the Group I Class I-B-4 Percentage of the Substitution
      Principal Amount with respect to each Group I Mortgage Loan for which a
      Group I Mortgage Loan was substituted during the one month period ending
      on the day preceding the Determination Date for such Distribution Date,
      less the amount allocable to the principal portion of any unreimbursed
      Periodic Advances previously made by the applicable Servicer, the Master
      Servicer or the Trustee in respect of such Group I Mortgage Loan for which
      a Group I Mortgage Loan was substituted; and

      (II) the Group I Class I-B-4 Prepayment Percentage of the Non-PO Recovery
      for such Loan Group for such Distribution Date;

provided, however, that if an Optimal Adjustment Event occurs with respect to
such Class and such Distribution Date, the Class I-B-4 Optimal Principal Amount
will equal the lesser of (A) the Class I-B-4 Optimal Principal Amount calculated
as described in the preceding provisions and (B) the Adjusted Principal Balance
for the Class I-B-4 Certificates.

      Class I-B-4 Principal Balance: As to the first Determination Date, the
Original Class I-B-4 Principal Balance. As of any subsequent Determination Date,
the Original Class I-B-4 Principal Balance less the sum of all amounts
previously distributed in respect of the Class I-B-4 Certificates on prior
Distribution Dates (A) pursuant to Paragraph sixteenth clause (A) of Section
4.01(a)(i) (including any principal otherwise payable to the Class I-B-4
Certificates used to pay any Class I-A-PO Deferred Amounts) and (B) as a result
of a Principal Adjustment; provided, however, if the Class I-B-4 Certificates
are the most subordinate Group I-B Certificates outstanding, the Class I-B-4
Principal Balance will equal the difference, if any, between the Group I
Adjusted Pool Amount (Non-PO Portion) as of the preceding Distribution Date less
the sum of the Group I-A Non-PO Principal Balance, the Class I-B-1 Principal
Balance, the Class I-B-2 Principal Balance and the Class I-B-3 Principal Balance
as of such Determination Date.

      Class I-B-4 Principal Distribution Amount: As to any Distribution Date,
any amount distributable to the Holders of the Class I-B-4 Certificates pursuant
to Paragraph sixteenth clause (A) of Section 4.01(a)(i).

      Class I-B-4 Unpaid Interest Shortfall: As to any Distribution Date, the
amount, if any, by which the aggregate of the Class I-B-4 Interest Shortfall
Amounts for prior Distribution Dates is in excess of the amounts distributed in
respect of the Class I-B-4 Certificates on prior Distribution Dates pursuant to
Paragraph fifteenth clause (A) of Section 4.01(a)(i).

      Class I-B-5 Certificate: Any one of the Certificates executed by the
Paying Agent and countersigned by the Authenticating Agent in substantially the
form set forth in Exhibit I-B-5 and Exhibit C hereto.

      Class I-B-5 Certificateholder: The registered holder of a Class I-B-5
Certificate.

      Class I-B-5 Distribution Amount: As to any Distribution Date, any amount
distributable to the Holders of the Class I-B-5 Certificates pursuant to
Paragraphs seventeenth clause (A), eighteenth clause (A) and nineteenth clause
(A) of Section 4.01(a)(i).

      Class I-B-5 Interest Shortfall Amount: As to any Distribution Date, any
amount by which the Interest Accrual Amount of the Class I-B-5 Certificates with
respect to such Distribution Date exceeds the amount distributed in respect of
the Class I-B-5 Certificates on such Distribution Date pursuant to Paragraph
seventeenth clause (A) of Section 4.01(a)(i).

      Class I-B-5 Optimal Principal Amount: As to any Distribution Date, an
amount equal to the sum of (I) the sum, as to each Group I Mortgage Loan that is
an Outstanding Mortgage Loan, of the product of (x) the Non-PO Fraction with
respect to such Group I Mortgage Loan and (y) the sum of:

            (i) the Group I Class I-B-5 Percentage of the principal portion of
      the Monthly Payment due on the Due Date occurring in the month of such
      Distribution Date on such Mortgage Loan;

            (ii) the Group I Class I-B-5 Prepayment Percentage (with respect to
      each such Group I Mortgage Loan) of all Unscheduled Principal Receipts
      (other than Recoveries) that were received by a Servicer with respect to
      such Group I Mortgage Loan during the Applicable Unscheduled Principal
      Receipt Period relating to such Distribution Date for each applicable type
      of Unscheduled Principal Receipt;

            (iii) the Group I Class I-B-5 Prepayment Percentage of the Scheduled
      Principal Balance of such Mortgage Loan which, during the one month period
      ending on the day preceding the Determination Date for such Distribution
      Date, was repurchased by the Depositor pursuant to Section 2.02, 2.03 or
      3.08; and

            (iv) the Group I Class I-B-5 Percentage of the Substitution
      Principal Amount with respect to each Group I Mortgage Loan for which a
      Group I Mortgage Loan was substituted during the one month period ending
      on the day preceding the Determination Date for such Distribution Date,
      less the amount allocable to the principal portion of any unreimbursed
      Periodic Advances previously made by the applicable Servicer, the Master
      Servicer or the Trustee in respect of such Group I Mortgage Loan for which
      a Group I Mortgage Loan was substituted; and

      (II) the Group I Class I-B-5 Prepayment Percentage of the Non-PO Recovery
      for such Loan Group for such Distribution Date;

provided, however, that if an Optimal Adjustment Event occurs with respect to
such Class and such Distribution Date, the Class I-B-5 Optimal Principal Amount
will equal the lesser of (A) the Class I-B-5 Optimal Principal Amount calculated
as described in the preceding provisions and (B) the Adjusted Principal Balance
for the Class I-B-5 Certificates.

      Class I-B-5 Principal Balance: As to the first Determination Date, the
Original Class I-B-5 Principal Balance. As of any subsequent Determination Date,
the Original Class I-B-5 Principal Balance less the sum of all amounts
previously distributed in respect of the Class I-B-5 Certificates on prior
Distribution Dates (A) pursuant to Paragraph nineteenth clause (A) of Section
4.01(a)(i) (including any principal otherwise payable to the Class I-B-5
Certificates used to pay any Class I-A-PO Deferred Amounts) and (B) as a result
of a Principal Adjustment; provided, however, if the Class I-B-5 Certificates
are the most subordinate Group I-B Certificates outstanding, the Class I-B-5
Principal Balance will equal the difference, if any, between the Group I
Adjusted Pool Amount (Non-PO Portion) as of the preceding Distribution Date less
the sum of the Group I-A Non-PO Principal Balance, the Class I-B-1 Principal
Balance, the Class I-B-2 Principal Balance, the Class I-B-3 Principal Balance
and the Class I-B-4 Principal Balance as of such Determination Date.

      Class I-B-5 Principal Distribution Amount: As to any Distribution Date,
any amount distributable to the Holders of the Class I-B-5 Certificates pursuant
to Paragraph nineteenth clause (A) of Section 4.01(a)(i).

      Class I-B-5 Unpaid Interest Shortfall: As to any Distribution Date, the
amount, if any, by which the aggregate of the Class I-B-5 Interest Shortfall
Amounts for prior Distribution Dates is in excess of the amounts distributed in
respect of the Class I-B-5 Certificates on prior Distribution Dates pursuant to
Paragraph eighteenth clause (A) of Section 4.01(a)(i).

      Class I-B-6 Certificate: Any one of the Certificates executed by the
Paying Agent and countersigned by the Authenticating Agent in substantially the
form set forth in Exhibit I-B-6 and Exhibit C hereto.

      Class I-B-6 Certificateholder: The registered holder of a Class I-B-6
Certificate.

      Class I-B-6 Distribution Amount: As to any Distribution Date, any amount
distributable to the Holders of the Class I-B-6 Certificates pursuant to
Paragraphs twentieth clause (A), twenty-first clause (A) and twenty-second
clause (A) of Section 4.01(a)(i).

      Class I-B-6 Interest Shortfall Amount: As to any Distribution Date, any
amount by which the Interest Accrual Amount of the Class I-B-6 Certificates with
respect to such Distribution Date exceeds the amount distributed in respect of
the Class I-B-6 Certificates on such Distribution Date pursuant to Paragraph
twentieth clause (A) of Section 4.01(a)(i).

      Class I-B-6 Optimal Principal Amount: As to any Distribution Date, an
amount equal to the sum of (I) the sum, as to each Group I Mortgage Loan that is
an Outstanding Mortgage Loan, of the product of (x) the Non-PO Fraction with
respect to such Group I Mortgage Loan and (y) the sum of:

            (i) the Group I Class I-B-6 Percentage of the principal portion of
      the Monthly Payment due on the Due Date occurring in the month of such
      Distribution Date on such Mortgage Loan;

            (ii) the Group I Class I-B-6 Prepayment Percentage (with respect to
      each such Group I Mortgage Loan) of all Unscheduled Principal Receipts
      (other than Recoveries) that were received by a Servicer with respect to
      such Group I Mortgage Loan during the Applicable Unscheduled Principal
      Receipt Period relating to such Distribution Date for each applicable type
      of Unscheduled Principal Receipt;

            (iii) the Group I Class I-B-6 Prepayment Percentage of the Scheduled
      Principal Balance of such Mortgage Loan which, during the one month period
      ending on the day preceding the Determination Date for such Distribution
      Date, was repurchased by the Depositor pursuant to Section 2.02, 2.03 or
      3.08; and

            (iv) the Group I Class I-B-6 Percentage of the Substitution
      Principal Amount with respect to each Group I Mortgage Loan for which a
      Group I Mortgage Loan was substituted during the one month period ending
      on the day preceding the Determination Date for such Distribution Date,
      less the amount allocable to the principal portion of any unreimbursed
      Periodic Advances previously made by the applicable Servicer, the Master
      Servicer or the Trustee in respect of such Group I Mortgage Loan for which
      a Group I Mortgage Loan was substituted; and

      (II) the Group I Class I-B-6 Prepayment Percentage of the Non-PO Recovery
      for such Loan Group for such Distribution Date;

provided, however, that if an Optimal Adjustment Event occurs with respect to
such Class and such Distribution Date, the Class I-B-6 Optimal Principal Amount
will equal the lesser of (A) the Class I-B-6 Optimal Principal Amount calculated
as described in the preceding provisions and (B) the Adjusted Principal Balance
for the Class I-B-6 Certificates.

      Class I-B-6 Principal Balance: As to the first Determination Date, the
Original Class I-B-6 Principal Balance. As of any subsequent Determination Date,
the Original Class I-B-6 Principal Balance less the sum of all amounts
previously distributed in respect of the Class I-B-6 Certificates on prior
Distribution Dates pursuant to Paragraph twenty-second clause (A) of Section
4.01(a)(i) (including any principal otherwise payable to the Class I-B-6
Certificates used to pay any Class I-A-PO Deferred Amounts); provided, however,
if the Class I-B-6 Certificates are outstanding, the Class I-B-6 Principal
Balance will equal the difference, if any, between the Group I Adjusted Pool
Amount (Non-PO Portion) as of the preceding Distribution Date less the sum of
the Group I-A Non-PO Principal Balance, the Class I-B-1 Principal Balance, the
Class I-B-2 Principal Balance, the Class I-B-3 Principal Balance, the Class
I-B-4 Principal Balance and the Class I-B-5 Principal Balance as of such
Determination Date.

      Class I-B-6 Principal Distribution Amount: As to any Distribution Date,
any amount distributable to the Holders of the Class I-B-6 Certificates pursuant
to Paragraph twenty-second clause (A) of Section 4.01(a)(i).

      Class I-B-6 Unpaid Interest Shortfall: As to any Distribution Date, the
amount, if any, by which the aggregate of the Class I-B-6 Interest Shortfall
Amounts for prior Distribution Dates is in excess of the amounts distributed in
respect of the Class I-B-6 Certificates on prior Distribution Dates pursuant to
Paragraph twenty-first clause (A) of Section 4.01(a)(i).

      Class II-B-1 Certificate: Any one of the Certificates executed by the
Paying Agent and countersigned by the Authenticating Agent in substantially the
form set forth in Exhibit II-B-1 and Exhibit C hereto.

      Class II-B-1 Certificateholder: The registered holder of a Class II-B-1
Certificate.

      Class II-B-1 Distribution Amount: As to any Distribution Date, any amount
distributable to the Holders of the Class II-B-1 Certificates pursuant to
Paragraphs fifth clause (B), sixth clause (B) and seventh clause (B) of Section
4.01(a)(i).

      Class II-B-1 Interest Shortfall Amount: As to any Distribution Date, any
amount by which the Interest Accrual Amount of the Class II-B-1 Certificates
with respect to such Distribution Date exceeds the amount distributed in respect
of the Class II-B-1 Certificates on such Distribution Date pursuant to Paragraph
fifth clause (B) of Section 4.01(a)(i).

      Class II-B-1 Optimal Principal Amount: As to any Distribution Date, an
amount equal to the sum of (I) the sum, as to each Group II Mortgage Loan that
is an Outstanding Mortgage Loan, of the product of (x) the Non-PO Fraction with
respect to such Group II Mortgage Loan and (y) the sum of:

            (i) the Group II Class II-B-1 Percentage of the principal portion of
      the Monthly Payment due on the Due Date occurring in the month of such
      Distribution Date on such Mortgage Loan;

            (ii) the Group II Class II-B-1 Prepayment Percentage (with respect
      to each such Group II Mortgage Loan) of all Unscheduled Principal Receipts
      (other than Recoveries) that were received by a Servicer with respect to
      such Group II Mortgage Loan during the Applicable Unscheduled Principal
      Receipt Period relating to such Distribution Date for each applicable type
      of Unscheduled Principal Receipt;

            (iii) the Group II Class II-B-1 Prepayment Percentage of the
      Scheduled Principal Balance of such Mortgage Loan which, during the one
      month period ending on the day preceding the Determination Date for such
      Distribution Date, was repurchased by the Depositor pursuant to Section
      2.02, 2.03 or 3.08; and

            (iv) the Group II Class II-B-1 Percentage of the Substitution
      Principal Amount with respect to each Group II Mortgage Loan for which a
      Group II Mortgage Loan was substituted during the one month period ending
      on the day preceding the Determination Date for such Distribution Date,
      less the amount allocable to the principal portion of any unreimbursed
      Periodic Advances previously made by the applicable Servicer, the Master
      Servicer or the Trustee in respect of such Group II Mortgage Loan for
      which a Group II Mortgage Loan was substituted; and

      (II) the Group II Class II-B-1 Prepayment Percentage of the Non-PO
      Recovery for such Loan Group for such Distribution Date;

provided, however, that if an Optimal Adjustment Event occurs with respect to
such Class and such Distribution Date, the Class II-B-1 Optimal Principal Amount
will equal the lesser of (A) the Class II-B-1 Optimal Principal Amount
calculated as described in the preceding provisions and (B) the Adjusted
Principal Balance for the Class II-B-1 Certificates.

      Class II-B-1 Principal Balance: As to the first Determination Date, the
Original Class II-B-1 Principal Balance. As of any subsequent Determination
Date, the Original Class II-B-1 Principal Balance less the sum of all amounts
previously distributed in respect of the Class II-B-1 Certificates on prior
Distribution Dates (A) pursuant to Paragraph seventh clause (B) of Section
4.01(a)(i) (including any principal otherwise payable to the Class II-B-1
Certificates used to pay any Class II-A-PO Deferred Amounts)and (B) as a result
of a Principal Adjustment; provided, however, if the Class II-B-1 Certificates
are the most subordinate Group II-B Certificates outstanding, the Class II-B-1
Principal Balance will equal the difference, if any, between the Group II
Adjusted Pool Amount (Non-PO Portion) as of the preceding Distribution Date less
the Group II-A Non-PO Principal Balance as of such Determination Date.

      Class II-B-1 Principal Distribution Amount: As to any Distribution Date,
any amount distributable to the Holders of the Class II-B-1 Certificates
pursuant to Paragraph seventh clause (B) of Section 4.01(a)(i).

      Class II-B-1 Unpaid Interest Shortfall: As to any Distribution Date, the
amount, if any, by which the aggregate of the Class II-B-1 Interest Shortfall
Amounts for prior Distribution Dates is in excess of the amounts distributed in
respect of the Class II-B-1 Certificates on prior Distribution Dates pursuant to
Paragraph sixth clause (B) of Section 4.01(a)(i).

      Class II-B-2 Certificate: Any one of the Certificates executed by the
Paying Agent and countersigned by the Authenticating Agent in substantially the
form set forth in Exhibit II-B-2 and Exhibit C hereto.

      Class II-B-2 Certificateholder: The registered holder of a Class II-B-2
Certificate.

      Class II-B-2 Distribution Amount: As to any Distribution Date, any amount
distributable to the Holders of the Class II-B-2 Certificates pursuant to
Paragraphs eighth clause (B), ninth clause (B) and tenth clause (B) of Section
4.01(a)( i).

      Class II-B-2 Interest Shortfall Amount: As to any Distribution Date, any
amount by which the Interest Accrual Amount of the Class II-B-2 Certificates
with respect to such Distribution Date exceeds the amount distributed in respect
of the Class II-B-2 Certificates on such Distribution Date pursuant to Paragraph
eighth clause (B) of Section 4.01(a)(i).

      Class II-B-2 Optimal Principal Amount: As to any Distribution Date, an
amount equal to the sum of (I) the sum, as to each Group II Mortgage Loan that
is an Outstanding Mortgage Loan, of the product of (x) the Non-PO Fraction with
respect to such Group II Mortgage Loan and (y) the sum of:

            (i) the Group II Class II-B-2 Percentage of the principal portion of
      the Monthly Payment due on the Due Date occurring in the month of such
      Distribution Date on such Mortgage Loan;

            (ii) the Group II Class II-B-2 Prepayment Percentage (with respect
      to each such Group II Mortgage Loan) of all Unscheduled Principal Receipts
      (other than Recoveries) that were received by a Servicer with respect to
      such Group II Mortgage Loan during the Applicable Unscheduled Principal
      Receipt Period relating to such Distribution Date for each applicable type
      of Unscheduled Principal Receipt;

            (iii) the Group II Class II-B-2 Prepayment Percentage of the
      Scheduled Principal Balance of such Mortgage Loan which, during the one
      month period ending on the day preceding the Determination Date for such
      Distribution Date, was repurchased by the Depositor pursuant to Section
      2.02, 2.03 or 3.08; and

            (iv) the Group II Class II-B-2 Percentage of the Substitution
      Principal Amount with respect to each Group II Mortgage Loan for which a
      Group II Mortgage Loan was substituted during the one month period ending
      on the day preceding the Determination Date for such Distribution Date,
      less the amount allocable to the principal portion of any unreimbursed
      Periodic Advances previously made by the applicable Servicer, the Master
      Servicer or the Trustee in respect of such Group II Mortgage Loan for
      which a Group II Mortgage Loan was substituted; and

      (II) the Group II Class II-B-2 Prepayment Percentage of the Non-PO
      Recovery for such Loan Group for such Distribution Date;

provided, however, that if an Optimal Adjustment Event occurs with respect to
such Class and such Distribution Date, the Class II-B-2 Optimal Principal Amount
will equal the lesser of (A) the Class II-B-2 Optimal Principal Amount
calculated as described in the preceding provisions and (B) the Adjusted
Principal Balance for the Class II-B-2 Certificates.

      Class II-B-2 Principal Balance: As to the first Determination Date, the
Original Class II-B-2 Principal Balance. As of any subsequent Determination
Date, the Original Class II-B-2 Principal Balance less the sum of all amounts
previously distributed in respect of the Class II-B-2 Certificates on prior
Distribution Dates (A) pursuant to Paragraph tenth clause (B) of Section
4.01(a)(i) (including any principal otherwise payable to the Class II-B-2
Certificates used to pay any Class II-A-PO Deferred Amounts) and (B) as a result
of a Principal Adjustment; provided, however, if the Class II-B-2 Certificates
are the most subordinate Group II-B Certificates outstanding, the Class II-B-2
Principal Balance will equal the difference, if any, between the Group II
Adjusted Pool Amount (Non-PO Portion) as of the preceding Distribution Date less
the sum of the Group II-A Non-PO Principal Balance and the Class II-B-1
Principal Balance as of such Determination Date.

      Class II-B-2 Principal Distribution Amount: As to any Distribution Date,
any amount distributable to the Holders of the Class II-B-2 Certificates
pursuant to Paragraph tenth clause (B) of Section 4.01(a)(i).

      Class II-B-2 Unpaid Interest Shortfall: As to any Distribution Date, the
amount, if any, by which the aggregate of the Class II-B-2 Interest Shortfall
Amounts for prior Distribution Dates is in excess of the amounts distributed in
respect of the Class II-B-2 Certificates on prior Distribution Dates pursuant to
Paragraph ninth clause (B) of Section 4.01(a)(i).

      Class II-B-3 Certificate: Any one of the Certificates executed by the
Paying Agent and countersigned by the Authenticating Agent in substantially the
form set forth in Exhibit II-B-3 and Exhibit C hereto.

      Class II-B-3 Certificateholder: The registered holder of a Class II-B-3
Certificate.

      Class II-B-3 Distribution Amount: As to any Distribution Date, any amount
distributable to the Holders of the Class II-B-3 Certificates pursuant to
Paragraphs eleventh clause (B), twelfth clause (B) and thirteenth clause (B) of
Section 4.01(a)(i).

      Class II-B-3 Interest Shortfall Amount: As to any Distribution Date, any
amount by which the Interest Accrual Amount of the Class II-B-3 Certificates
with respect to such Distribution Date exceeds the amount distributed in respect
of the Class II-B-3 Certificates on such Distribution Date pursuant to Paragraph
eleventh clause (B) of Section 4.01(a)(i).

      Class II-B-3 Optimal Principal Amount: As to any Distribution Date, an
amount equal to the sum of (I) the sum, as to each Group II Mortgage Loan that
is an Outstanding Mortgage Loan, of the product of (x) the Non-PO Fraction with
respect to such Group II Mortgage Loan and (y) the sum of:

            (i) the Group II Class II-B-3 Percentage of the principal portion of
      the Monthly Payment due on the Due Date occurring in the month of such
      Distribution Date on such Mortgage Loan;

            (ii) the Group II Class II-B-3 Prepayment Percentage (with respect
      to each such Group II Mortgage Loan) of all Unscheduled Principal Receipts
      (other than Recoveries) that were received by a Servicer with respect to
      such Group II Mortgage Loan during the Applicable Unscheduled Principal
      Receipt Period relating to such Distribution Date for each applicable type
      of Unscheduled Principal Receipt;

            (iii) the Group II Class II-B-3 Prepayment Percentage of the
      Scheduled Principal Balance of such Mortgage Loan which, during the one
      month period ending on the day preceding the Determination Date for such
      Distribution Date, was repurchased by the Depositor pursuant to Section
      2.02, 2.03 or 3.08; and

            (iv) the Group II Class II-B-3 Percentage of the Substitution
      Principal Amount with respect to each Group II Mortgage Loan for which a
      Group II Mortgage Loan was substituted during the one month period ending
      on the day preceding the Determination Date for such Distribution Date,
      less the amount allocable to the principal portion of any unreimbursed
      Periodic Advances previously made by the applicable Servicer, the Master
      Servicer or the Trustee in respect of such Group II Mortgage Loan for
      which a Group II Mortgage Loan was substituted; and

      (II) the Group II Class II-B-3 Prepayment Percentage of the Non-PO
      Recovery for such Loan Group for such Distribution Date;

provided, however, that if an Optimal Adjustment Event occurs with respect to
such Class and such Distribution Date, the Class II-B-3 Optimal Principal Amount
will equal the lesser of (A) the Class II-B-3 Optimal Principal Amount
calculated as described in the preceding provisions and (B) the Adjusted
Principal Balance for the Class II-B-3 Certificates.

      Class II-B-3 Principal Balance: As to the first Determination Date, the
Original Class II-B-3 Principal Balance. As of any subsequent Determination
Date, the Original Class II-B-3 Principal Balance less the sum of all amounts
previously distributed in respect of the Class II-B-3 Certificates on prior
Distribution Dates (A) pursuant to Paragraph thirteenth clause (B) of Section
4.01(a)(i) (including any principal otherwise payable to the Class II-B-3
Certificates used to pay any Class II-A-PO Deferred Amounts) and (B) as a result
of a Principal Adjustment; provided, however, if the Class II-B-3 Certificates
are the most subordinate Group II-B Certificates outstanding, the Class II-B-3
Principal Balance will equal the difference, if any, between the Group II
Adjusted Pool Amount (Non-PO Portion) as of the preceding Distribution Date less
the sum of the Group II-A Non-PO Principal Balance, the Class II-B-1 Principal
Balance and the Class II-B-2 Principal Balance as of such Determination Date.

      Class II-B-3 Principal Distribution Amount: As to any Distribution Date,
any amount distributable to the Holders of the Class II-B-3 Certificates
pursuant to Paragraph thirteenth clause (B) of Section 4.01(a)(i).

      Class II-B-3 Unpaid Interest Shortfall: As to any Distribution Date, the
amount, if any, by which the aggregate of the Class II-B-3 Interest Shortfall
Amounts for prior Distribution Dates is in excess of the amounts distributed in
respect of the Class II-B-3 Certificates on prior Distribution Dates pursuant to
Paragraph twelfth clause (B) of Section 4.01(a)(i).

      Class II-B-4 Certificate: Any one of the Certificates executed by the
Paying Agent and countersigned by the Authenticating Agent in substantially the
form set forth in Exhibit II-B-4 and Exhibit C hereto.

      Class II-B-4 Certificateholder: The registered holder of a Class II-B-4
Certificate.

      Class II-B-4 Distribution Amount: As to any Distribution Date, any amount
distributable to the Holders of the Class II-B-4 Certificates pursuant to
Paragraphs fourteenth clause (B), fifteenth clause (B) and sixteenth clause (B)
of Section 4.01(a)(i).

      Class II-B-4 Interest Shortfall Amount: As to any Distribution Date, any
amount by which the Interest Accrual Amount of the Class II-B-4 Certificates
with respect to such Distribution Date exceeds the amount distributed in respect
of the Class II-B-4 Certificates on such Distribution Date pursuant to Paragraph
fourteenth clause (B) of Section 4.01(a)(i).

      Class II-B-4 Optimal Principal Amount: As to any Distribution Date, an
amount equal to the sum of (I) the sum, as to each Group II Mortgage Loan that
is an Outstanding Mortgage Loan, of the product of (x) the Non-PO Fraction with
respect to such Group II Mortgage Loan and (y) the sum of:

            (i) the Group II Class II-B-4 Percentage of the principal portion of
      the Monthly Payment due on the Due Date occurring in the month of such
      Distribution Date on such Mortgage Loan;

            (ii) the Group II Class II-B-4 Prepayment Percentage (with respect
      to each such Group II Mortgage Loan) of all Unscheduled Principal Receipts
      (other than Recoveries) that were received by a Servicer with respect to
      such Group II Mortgage Loan during the Applicable Unscheduled Principal
      Receipt Period relating to such Distribution Date for each applicable type
      of Unscheduled Principal Receipt;

            (iii) the Group II Class II-B-4 Prepayment Percentage of the
      Scheduled Principal Balance of such Mortgage Loan which, during the one
      month period ending on the day preceding the Determination Date for such
      Distribution Date, was repurchased by the Depositor pursuant to Section
      2.02, 2.03 or 3.08; and

            (iv) the Group II Class II-B-4 Percentage of the Substitution
      Principal Amount with respect to each Group II Mortgage Loan for which a
      Group II Mortgage Loan was substituted during the one month period ending
      on the day preceding the Determination Date for such Distribution Date,
      less the amount allocable to the principal portion of any unreimbursed
      Periodic Advances previously made by the applicable Servicer, the Master
      Servicer or the Trustee in respect of such Group II Mortgage Loan for
      which a Group II Mortgage Loan was substituted; and

      (II) the Group II Class II-B-4 Prepayment Percentage of the Non-PO
      Recovery for such Loan Group for such Distribution Date;

provided, however, that if an Optimal Adjustment Event occurs with respect to
such Class and such Distribution Date, the Class II-B-4 Optimal Principal Amount
will equal the lesser of (A) the Class II-B-4 Optimal Principal Amount
calculated as described in the preceding provisions and (B) the Adjusted
Principal Balance for the Class II-B-4 Certificates.

      Class II-B-4 Principal Balance: As to the first Determination Date, the
Original Class II-B-4 Principal Balance. As of any subsequent Determination
Date, the Original Class II-B-4 Principal Balance less the sum of all amounts
previously distributed in respect of the Class II-B-4 Certificates on prior
Distribution Dates (A) pursuant to Paragraph sixteenth clause (B) of Section
4.01(a)(i) (including any principal otherwise payable to the Class II-B-4
Certificates used to pay any Class II-A-PO Deferred Amounts) and (B) as a result
of a Principal Adjustment; provided, however, if the Class II-B-4 Certificates
are the most subordinate Group II-B Certificates outstanding, the Class II-B-4
Principal Balance will equal the difference, if any, between the Group II
Adjusted Pool Amount (Non-PO Portion) as of the preceding Distribution Date less
the sum of the Group II-A Non-PO Principal Balance, the Class II-B-1 Principal
Balance, the Class II-B-2 Principal Balance and the Class II-B-3 Principal
Balance as of such Determination Date.

      Class II-B-4 Principal Distribution Amount: As to any Distribution Date,
any amount distributable to the Holders of the Class II-B-4 Certificates
pursuant to Paragraph sixteenth clause (B) of Section 4.01(a)(i).

      Class II-B-4 Unpaid Interest Shortfall: As to any Distribution Date, the
amount, if any, by which the aggregate of the Class II-B-4 Interest Shortfall
Amounts for prior Distribution Dates is in excess of the amounts distributed in
respect of the Class II-B-4 Certificates on prior Distribution Dates pursuant to
Paragraph fifteenth clause (B) of Section 4.01(a)(i).

      Class II-B-5 Certificate: Any one of the Certificates executed by the
Paying Agent and countersigned by the Authenticating Agent in substantially the
form set forth in Exhibit II-B-5 and Exhibit C hereto.

      Class II-B-5 Certificateholder: The registered holder of a Class II-B-5
Certificate.

      Class II-B-5 Distribution Amount: As to any Distribution Date, any amount
distributable to the Holders of the Class II-B-5 Certificates pursuant to
Paragraphs seventeenth clause (B), eighteenth clause (B) and nineteenth clause
(B) of Section 4.01(a)(i).

      Class II-B-5 Interest Shortfall Amount: As to any Distribution Date, any
amount by which the Interest Accrual Amount of the Class II-B-5 Certificates
with respect to such Distribution Date exceeds the amount distributed in respect
of the Class II-B-5 Certificates on such Distribution Date pursuant to Paragraph
seventeenth clause (B) of Section 4.01(a)(i).

      Class II-B-5 Optimal Principal Amount: As to any Distribution Date, an
amount equal to the sum of (I) the sum, as to each Group II Mortgage Loan that
is an Outstanding Mortgage Loan, of the product of (x) the Non-PO Fraction with
respect to such Group II Mortgage Loan and (y) the sum of:

            (i) the Group II Class II-B-5 Percentage of the principal portion of
      the Monthly Payment due on the Due Date occurring in the month of such
      Distribution Date on such Mortgage Loan;

            (ii) the Group II Class II-B-5 Prepayment Percentage (with respect
      to each such Group II Mortgage Loan) of all Unscheduled Principal Receipts
      (other than Recoveries) that were received by a Servicer with respect to
      such Group II Mortgage Loan during the Applicable Unscheduled Principal
      Receipt Period relating to such Distribution Date for each applicable type
      of Unscheduled Principal Receipt;

            (iii) the Group II Class II-B-5 Prepayment Percentage of the
      Scheduled Principal Balance of such Mortgage Loan which, during the one
      month period ending on the day preceding the Determination Date for such
      Distribution Date, was repurchased by the Depositor pursuant to Section
      2.02, 2.03 or 3.08; and

            (iv) the Group II Class II-B-5 Percentage of the Substitution
      Principal Amount with respect to each Group II Mortgage Loan for which a
      Group II Mortgage Loan was substituted during the one month period ending
      on the day preceding the Determination Date for such Distribution Date,
      less the amount allocable to the principal portion of any unreimbursed
      Periodic Advances previously made by the applicable Servicer, the Master
      Servicer or the Trustee in respect of such Group II Mortgage Loan for
      which a Group II Mortgage Loan was substituted; and

      (II) the Group II Class II-B-5 Prepayment Percentage of the Non-PO
      Recovery for such Loan Group for such Distribution Date;

provided, however, that if an Optimal Adjustment Event occurs with respect to
such Class and such Distribution Date, the Class II-B-5 Optimal Principal Amount
will equal the lesser of (A) the Class II-B-5 Optimal Principal Amount
calculated as described in the preceding provisions and (B) the Adjusted
Principal Balance for the Class II-B-5 Certificates.

      Class II-B-5 Principal Balance: As to the first Determination Date, the
Original Class II-B-5 Principal Balance. As of any subsequent Determination
Date, the Original Class II-B-5 Principal Balance less the sum of all amounts
previously distributed in respect of the Class II-B-5 Certificates on prior
Distribution Dates (A) pursuant to Paragraph nineteenth clause (B) of Section
4.01(a)(i) (including any principal otherwise payable to the Class II-B-5
Certificates used to pay any Class II-A-PO Deferred Amounts) and (B) as a result
of a Principal Adjustment; provided, however, if the Class II-B-5 Certificates
are the most subordinate Group II-B Certificates outstanding, the Class II-B-5
Principal Balance will equal the difference, if any, between the Group II
Adjusted Pool Amount (Non-PO Portion) as of the preceding Distribution Date less
the sum of the Group II-A Non-PO Principal Balance, the Class II-B-1 Principal
Balance, the Class II-B-2 Principal Balance, the Class II-B-3 Principal Balance
and the Class II-B-4 Principal Balance as of such Determination Date.

      Class II-B-5 Principal Distribution Amount: As to any Distribution Date,
any amount distributable to the Holders of the Class II-B-5 Certificates
pursuant to Paragraph nineteenth clause (B) of Section 4.01(a)(i).

      Class II-B-5 Unpaid Interest Shortfall: As to any Distribution Date, the
amount, if any, by which the aggregate of the Class II-B-5 Interest Shortfall
Amounts for prior Distribution Dates is in excess of the amounts distributed in
respect of the Class II-B-5 Certificates on prior Distribution Dates pursuant to
Paragraph eighteenth clause (B) of Section 4.01(a)(i).

      Class II-B-6 Certificate: Any one of the Certificates executed by the
Paying Agent and countersigned by the Authenticating Agent in substantially the
form set forth in Exhibit II-B-6 and Exhibit C hereto.

      Class II-B-6 Certificateholder: The registered holder of a Class II-B-6
Certificate.

      Class II-B-6 Distribution Amount: As to any Distribution Date, any amount
distributable to the Holders of the Class II-B-6 Certificates pursuant to
Paragraphs twentieth clause (B), twenty-first clause (B) and twenty-second
clause (B) of Section 4.01(a)(i).

      Class II-B-6 Interest Shortfall Amount: As to any Distribution Date, any
amount by which the Interest Accrual Amount of the Class II-B-6 Certificates
with respect to such Distribution Date exceeds the amount distributed in respect
of the Class II-B-6 Certificates on such Distribution Date pursuant to Paragraph
twentieth clause (B) of Section 4.01(a)(i).

      Class II-B-6 Optimal Principal Amount: As to any Distribution Date, an
amount equal to the sum of (I) the sum, as to each Group II Mortgage Loan that
is an Outstanding Mortgage Loan, of the product of (x) the Non-PO Fraction with
respect to such Group II Mortgage Loan and (y) the sum of:

            (i) the Group II Class II-B-6 Percentage of the principal portion of
      the Monthly Payment due on the Due Date occurring in the month of such
      Distribution Date on such Mortgage Loan;

            (ii) the Group II Class II-B-6 Prepayment Percentage (with respect
      to each such Group II Mortgage Loan) of all Unscheduled Principal Receipts
      (other than Recoveries) that were received by a Servicer with respect to
      such Group II Mortgage Loan during the Applicable Unscheduled Principal
      Receipt Period relating to such Distribution Date for each applicable type
      of Unscheduled Principal Receipt;

            (iii) the Group II Class II-B-6 Prepayment Percentage of the
      Scheduled Principal Balance of such Mortgage Loan which, during the one
      month period ending on the day preceding the Determination Date for such
      Distribution Date, was repurchased by the Depositor pursuant to Section
      2.02, 2.03 or 3.08; and

            (iv) the Group II Class II-B-6 Percentage of the Substitution
      Principal Amount with respect to each Group II Mortgage Loan for which a
      Group II Mortgage Loan was substituted during the one month period ending
      on the day preceding the Determination Date for such Distribution Date,
      less the amount allocable to the principal portion of any unreimbursed
      Periodic Advances previously made by the applicable Servicer, the Master
      Servicer or the Trustee in respect of such Group II Mortgage Loan for
      which a Group II Mortgage Loan was substituted; and

      (II) the Group II Class II-B-6 Prepayment Percentage of the Non-PO
      Recovery for such Loan Group for such Distribution Date;

provided, however, that if an Optimal Adjustment Event occurs with respect to
such Class and such Distribution Date, the Class II-B-6 Optimal Principal Amount
will equal the lesser of (A) the Class II-B-6 Optimal Principal Amount
calculated as described in the preceding provisions and (B) the Adjusted
Principal Balance for the Class II-B-6 Certificates.

      Class II-B-6 Principal Balance: As to the first Determination Date, the
Original Class II-B-6 Principal Balance. As of any subsequent Determination
Date, the Original Class II-B-6 Principal Balance less the sum of all amounts
previously distributed in respect of the Class II-B-6 Certificates on prior
Distribution Dates pursuant to Paragraph twenty-second clause (B) of Section
4.01(a)(i) (including any principal otherwise payable to the Class II-B-6
Certificates used to pay any Class II-A-PO Deferred Amounts); provided, however,
if the Class II-B-6 Certificates are outstanding, the Class II-B-6 Principal
Balance will equal the difference, if any, between the Group II Adjusted Pool
Amount as of the preceding Distribution Date less the sum of the Group II-A
Non-PO Principal Balance, the Class II-B-1 Principal Balance, the Class II-B-2
Principal Balance, the Class II-B-3 Principal Balance, the Class II-B-4
Principal Balance and the Class II-B-5 Principal Balance as of such
Determination Date.

      Class II-B-6 Principal Distribution Amount: As to any Distribution Date,
any amount distributable to the Holders of the Class II-B-6 Certificates
pursuant to Paragraph twenty-second clause (B) of Section 4.01(a)(i).

      Class II-B-6 Unpaid Interest Shortfall: As to any Distribution Date, the
amount, if any, by which the aggregate of the Class II-B-6 Interest Shortfall
Amounts for prior Distribution Dates is in excess of the amounts distributed in
respect of the Class II-B-6 Certificates on prior Distribution Dates pursuant to
Paragraph twenty-first clause (B) of Section 4.01(a)(i).

      Class B Certificate: Any one of the Class I-B-1 Certificates, Class I-B-2
Certificates, Class I-B-3 Certificates, Class I-B-4 Certificates, Class I-B-5
Certificates, Class I-B-6 Certificates, Class II-B-1 Certificates, Class II-B-2
Certificates, Class II-B-3 Certificates, Class II-B-4 Certificates, Class II-B-5
Certificates or Class II-B-6 Certificates.

      Class B Certificateholder: The registered holder of a Class B Certificate.

      Class B Distribution Amount: Any of the Class I-B-1, Class I-B-2, Class
I-B-3, Class I-B-4, Class I-B-5, Class I-B-6, Class II-B-1, Class II-B-2, Class
II-B-3, Class II-B-4, Class II-B-5 or Class II-B-6 Distribution Amounts.

      Class B Interest Accrual Amount: For a Group, as to any Distribution Date,
the sum of the Interest Accrual Amounts for the Classes of Class B Certificates
of such Group with respect to such Distribution Date.

      Class B Interest Percentage: For a Group, as to any Distribution Date and
any Class of Class B Certificates of such Group, the percentage calculated by
dividing the Interest Accrual Amount of such Class (determined without regard to
clause (ii) of the definition thereof) by the Class B Interest Accrual Amount
for such Group (determined without regard to clause (ii) of the definition of
each Interest Accrual Amount).

      Class B Interest Shortfall Amount: Any of the Class I-B-1 Interest
Shortfall Amount, Class I-B-2 Interest Shortfall Amount, Class I-B-3 Interest
Shortfall Amount, Class I-B-4 Interest Shortfall Amount, Class I-B-5 Interest
Shortfall Amount, Class I-B-6 Interest Shortfall Amount, Class II-B-1 Interest
Shortfall Amount, Class II-B-2 Interest Shortfall Amount, Class II-B-3 Interest
Shortfall Amount, Class II-B-4 Interest Shortfall Amount, Class II-B-5 Interest
Shortfall Amount or Class II-B-6 Interest Shortfall Amount.

      Class B Optimal Principal Amount: Any of the Class I-B-1, Class I-B-2,
Class I-B-3, Class I-B-4, Class I-B-5, Class I-B-6, Class II-B-1, Class II-B-2,
Class II-B-3, Class II-B-4, Class II-B-5 or Class II-B-6 Optimal Principal
Amounts.

      Class B Pass-Through Rate: With respect to any Distribution Date, a per
annum rate equal to 5.750%.

      Class B Unpaid Interest Shortfall: Any of the Class I-B-1 Unpaid Interest
Shortfall, Class I-B-2 Unpaid Interest Shortfall, Class I-B-3 Unpaid Interest
Shortfall, Class I-B-4 Unpaid Interest Shortfall, Class I-B-5 Unpaid Interest
Shortfall, Class I-B-6 Unpaid Interest Shortfall, Class II-B-1 Unpaid Interest
Shortfall, Class II-B-2 Unpaid Interest Shortfall, Class II-B-3 Unpaid Interest
Shortfall, Class II-B-4 Unpaid Interest Shortfall, Class II-B-5 Unpaid Interest
Shortfall or Class II-B-6 Unpaid Interest Shortfall.

      Clearing Agency: An organization registered as a "clearing agency"
pursuant to Section 17A of the Exchange Act. The initial Clearing Agency shall
be The Depository Trust Company.

      Clearing Agency Participant: A broker, dealer, bank, financial institution
or other Person for whom a Clearing Agency effects book-entry transfers of
securities deposited with the Clearing Agency.

      Closing Date: The date of initial issuance of the Certificates, as set
forth in Section 11.23.

      Code: The Internal Revenue Code of 1986, as it may be amended from time to
time, any successor statutes thereto, and applicable U.S. Department of the
Treasury temporary or final regulations promulgated thereunder.

      Commission: The United States Securities and Exchange Commission.

      Compensating Interest: With respect to any Distribution Date and each
Group, the least of (a) the aggregate Prepayment Interest Shortfall on the
Mortgage Loans in the related Loan Group for such Distribution Date, (b) the
product of (i) 1/12th of 0.20% and (ii) the Pool Balance of the Mortgage Loans
in the related Loan Group for such Distribution Date and (c) the Available
Master Servicing Compensation with respect to such Loan Group for such
Distribution Date.

      Co-op Shares: Shares issued by private non-profit housing corporations.

      Corporate Trust Office: With respect to (a) the Trustee, the office of the
Trustee at which at any particular time its duties under this Agreement shall be
administered, which office, at the date of the execution of this instrument, is
located at 209 South LaSalle Street, 3rd Floor, Chicago, Illinois 60604-1219 and
(b) the Paying Agent, Certificate Registrar and Authenticating Agent, for
Certificate transfer purposes at Wells Fargo Center, Sixth Street and Marquette
Avenue, Minneapolis, Minnesota 55479 Attn: Corporate Trust Services--WFMBS
2006-4, and for all other purposes at 9062 Old Annapolis Blvd., Columbia,
Maryland 21045 Attn: Corporate Trust Services--WFMBS 2006-4.

      Corresponding Upper-Tier Class or Classes: As to the following
Uncertificated Lower-Tier Interests, the Corresponding Upper-Tier Class or
Classes as follows:

Uncertificated Lower-Tier Interest    Corresponding Upper-Tier Class or Classes
----------------------------------    -----------------------------------------

      Class I-A-L1 Interest           Class I-A-1, Class I-A-2, Class I-A-3,
                                      Class I-A-4, Class I-A-7, Class I-A-8,
                                      Class I-A-9, Class I-A-10, Class I-A-11,
                                      Class I-A-12, Class I-A-13 and Class
                                      I-A-14 Certificates

      Class I-A-L5 Interest           Class I-A-5 and Class I-A-6 Certificates

      Class I-A-LPO Interest          Class I-A-PO Certificates

      Class I-A-LUR Interest          Class I-A-R Interest

      Class II-A-L1 Interest          Class II-A-1 Certificates

      Class II-A-L2 Interest          Class II-A-2 Certificates

      Class II-A-L3 Interest          Class II-A-3 Certificates

      Class II-A-LPO Interest         Class II-A-PO Certificates

      Class I-B-L1 Interest           Class I-B-1 Certificates

      Class I-B-L2 Interest           Class I-B-2 Certificates

      Class I-B-L3 Interest           Class I-B-3 Certificates

      Class I-B-L4 Interest           Class I-B-4 Certificates

      Class I-B-L5 Interest           Class I-B-5 Certificates

      Class I-B-L6 Interest           Class I-B-6 Certificates

      Class II-B-L1 Interest          Class II-B-1 Certificates

      Class II-B-L2 Interest          Class II-B-2 Certificates

      Class II-B-L3 Interest          Class II-B-3 Certificates

      Class II-B-L4 Interest          Class II-B-4 Certificates

      Class II-B-L5 Interest          Class II-B-5 Certificates

      Class II-B-L6 Interest          Class II-B-6 Certificates

      Counterparty: The Royal Bank of Scotland plc.

      Current Class B Interest Distribution Amount: For a Group and as to any
Distribution Date, the amount distributed in respect of the Classes of Class B
Certificates of such Group pursuant to Paragraphs fifth, eighth, eleventh,
fourteenth, seventeenth and twentieth clause (A) or (B), as applicable of
Section 4.01(a)(i) on such Distribution Date.

      Current Class I-B-1 Fractional Interest: As to any Distribution Date
subsequent to the first Distribution Date, the percentage obtained by dividing
the sum of the Principal Balances of the Class I-B-2, Class I-B-3, Class I-B-4,
Class I-B-5 and Class I-B-6 Certificates by the Group I Aggregate Non-PO
Principal Balance. As to the first Distribution Date, the Original Class I-B-1
Fractional Interest.

      Current Class I-B-2 Fractional Interest: As to any Distribution Date
subsequent to the first Distribution Date, the percentage obtained by dividing
the sum of the Principal Balances of the Class I-B-3, Class I-B-4, Class I-B-5
and Class I-B-6 Certificates by the Group I Aggregate Non-PO Principal Balance.
As to the first Distribution Date, the Original Class I-B-2 Fractional Interest.

      Current Class I-B-3 Fractional Interest: As to any Distribution Date
subsequent to the first Distribution Date, the percentage obtained by dividing
the sum of the Principal Balances of the Class I-B-4, Class I-B-5 and Class
I-B-6 Certificates by the Group I Aggregate Non-PO Principal Balance. As to the
first Distribution Date, the Original Class I-B-3 Fractional Interest.

      Current Class I-B-4 Fractional Interest: As to any Distribution Date
subsequent to the first Distribution Date, the percentage obtained by dividing
the sum of the Principal Balances of the Class I-B-5 and Class I-B-6
Certificates by the Group I Aggregate Non-PO Principal Balance. As to the first
Distribution Date, the Original Class I-B-4 Fractional Interest.

      Current Class I-B-5 Fractional Interest: As to any Distribution Date
subsequent to the first Distribution Date, the percentage obtained by dividing
the Principal Balance of the Class I-B-6 Certificates by the Group I Aggregate
Non-PO Principal Balance. As to the first Distribution Date, the Original Class
I-B-5 Fractional Interest.

      Current Class II-B-1 Fractional Interest: As to any Distribution Date
subsequent to the first Distribution Date, the percentage obtained by dividing
the sum of the Principal Balances of the Class II-B-2, Class II-B-3, Class
II-B-4, Class II-B-5 and Class II-B-6 Certificates by the Group II Aggregate
Non-PO Principal Balance. As to the first Distribution Date, the Original Class
II-B-1 Fractional Interest.

      Current Class II-B-2 Fractional Interest: As to any Distribution Date
subsequent to the first Distribution Date, the percentage obtained by dividing
the sum of the Principal Balances of the Class II-B-3, Class II-B-4, Class
II-B-5 and Class II-B-6 Certificates by the Group II Aggregate Non-PO Principal
Balance. As to the first Distribution Date, the Original Class II-B-2 Fractional
Interest.

      Current Class II-B-3 Fractional Interest: As to any Distribution Date
subsequent to the first Distribution Date, the percentage obtained by dividing
the sum of the Principal Balances of the Class II-B-4, Class II-B-5 and Class
II-B-6 Certificates by the Group II Aggregate Non-PO Principal Balance. As to
the first Distribution Date, the Original Class II-B-3 Fractional Interest.

      Current Class II-B-4 Fractional Interest: As to any Distribution Date
subsequent to the first Distribution Date, the percentage obtained by dividing
the sum of the Principal Balances of the Class II-B-5 and Class II-B-6
Certificates by the Group II Aggregate Non-PO Principal Balance. As to the first
Distribution Date, the Original Class II-B-4 Fractional Interest.

      Current Class II-B-5 Fractional Interest: As to any Distribution Date
subsequent to the first Distribution Date, the percentage obtained by dividing
the Principal Balance of the Class II-B-6 Certificates by the Group II Aggregate
Non-PO Principal Balance. As to the first Distribution Date, the Original Class
II-B-5 Fractional Interest.

      Current Group I-A Interest Distribution Amount: As to any Distribution
Date, the amount distributed in respect of the Classes of Group I-A Certificates
pursuant to Paragraph first clause (A) of Section 4.01(a)(i) on such
Distribution Date.

      Current Group II-A Interest Distribution Amount: As to any Distribution
Date, the amount distributed in respect of the Classes of Group II-A
Certificates pursuant to Paragraph first clause (B) of Section 4.01(a)(i) on
such Distribution Date.

      Curtailment: Any Principal Prepayment made by a Mortgagor which is not a
Prepayment in Full.

      Curtailment Interest Shortfall: On any Distribution Date with respect to a
Group I or Group II Mortgage Loan which was the subject of a Curtailment:

      (A)   in the case where the Applicable Unscheduled Principal Receipt
            Period is the Mid-Month Receipt Period and such Curtailment is
            received by the Servicer on or after the Determination Date in the
            month preceding the month of such Distribution Date but prior to the
            first day of the month of such Distribution Date, the amount of
            interest that would have accrued at the Net Mortgage Interest Rate
            on the amount of such Curtailment from the day of its receipt or, if
            earlier, its application by the Servicer through the last day of the
            month preceding the month of such Distribution Date; and

      (B)   in the case where the Applicable Unscheduled Principal Receipt
            Period is the Prior Month Receipt Period and such Curtailment is
            received by the Servicer during the month preceding the month of
            such Distribution Date, the amount of interest that would have
            accrued at the Net Mortgage Interest Rate on the amount of such
            Curtailment from the day of its receipt or, if earlier, its
            application by the Servicer through the last day of the month in
            which such Curtailment is received.

      Custodial Agreement: The Custodial Agreement, dated as of March 30, 2006,
among the Custodian, the Depositor, the Master Servicer and the Trustee, which
agreement is attached hereto as Exhibit E, as the same may be amended or
modified from time to time in accordance with the terms thereof.

      Custodial P&I Account: The Custodial P&I Account, as defined in each of
the Servicing Agreements, with respect to the Mortgage Loans. In determining
whether the Custodial P&I Account under any Servicing Agreement is "acceptable"
to the Master Servicer (as may be required by the definition of "Eligible
Account" contained in the Servicing Agreements), the Master Servicer shall
require that any such account shall be acceptable to each of the Rating
Agencies.

      Custodian: Wells Fargo Bank, or its successor in interest under the
Custodial Agreement. Initially, the custodial functions shall be performed by
the Corporate Trust Services division of Wells Fargo Bank.

      Cut-Off Date: The first day of the month of initial issuance of the
Certificates as set forth in Section 11.01.

      Cut-Off Date Aggregate Principal Balance: The aggregate of the Cut-Off
Date Principal Balances of the Mortgage Loans as set forth in Section 11.02.

      Cut-Off Date Principal Balance: As to each Mortgage Loan, its unpaid
principal balance as of the close of business on the Cut-Off Date (but without
giving effect to any Unscheduled Principal Receipts received or applied on the
Cut-Off Date), reduced by all payments of principal due on or before the Cut-Off
Date and not paid, and increased by scheduled monthly payments of principal due
after the Cut-Off Date but received by the related Servicer on or before the
Cut-Off Date.

      Debt Service Reduction: With respect to any Mortgage Loan, a reduction in
the scheduled Monthly Payment for such Mortgage Loan by a court of competent
jurisdiction in a proceeding under the Bankruptcy Code, except such a reduction
constituting a Deficient Valuation.

      Deficient Valuation: With respect to any Mortgage Loan, a valuation by a
court of competent jurisdiction of the Mortgaged Property in an amount less than
the then-outstanding indebtedness under the Mortgage Loan, or any reduction in
the amount of principal to be paid in connection with any scheduled Monthly
Payment that results in a permanent forgiveness of principal, which valuation or
reduction results from a proceeding under the Bankruptcy Code.

      Definitive Certificates: As defined in Section 5.01(b).

      Denomination: The amount, if any, specified on the face of each
Certificate (other than the Class I-A-6 Certificates) representing the principal
portion of the Cut-Off Date Aggregate Principal Balance evidenced by such
Certificate. As to the Class I-A-6 Certificates, the amount specified on the
face of each such Certificate representing the portion of the Original Notional
Amount.

      Depositor: Wells Fargo Asset Securities Corporation, or its successor in
interest.

      Determination Date: The 17th day of the month in which the related
Distribution Date occurs, or if such 17th day is not a Business Day, the
Business Day preceding such 17th day.

      Discount Mortgage Loan: A Group I Discount Mortgage Loan or Group II
Discount Mortgage Loan.

      Distribution Date: The 25th day of any month, beginning in the month
following the month of initial issuance of the Certificates, or if such 25th day
is not a Business Day, the Business Day following such 25th day.

      Distribution Date Statement: As defined in Section 4.04(a).

      Document Transfer Date: The 60th day following the occurrence of a
Document Transfer Event.

      Document Transfer Event: The occurrence of either of the following: (i)
Wells Fargo Bank is no longer the Servicer of any of the Mortgage Loans or (ii)
the senior, unsecured long-term debt rating of Wells Fargo & Company is less
than "BBB-" by Fitch.

      Due Date: With respect to any Mortgage Loan, the day of the month in which
the Monthly Payment on such Mortgage Loan is scheduled to be paid.

      Eligible Account: One or more accounts (i) that are maintained with a
depository institution (which may be the Master Servicer) whose long-term debt
obligations (or, in the case of a depository institution which is part of a
holding company structure, the long-term debt obligations of such parent holding
company) at the time of deposit therein are rated at least "AA" (or the
equivalent) by each Rating Agency, (ii) the deposits in which are fully insured
by the FDIC through either the Bank Insurance Fund or the Savings Association
Insurance Fund, (iii) the deposits in which are insured by the FDIC through
either the Bank Insurance Fund or the Savings Association Insurance Fund (to the
limit established by the FDIC) and the uninsured deposits in which accounts are
otherwise secured, as evidenced by an Opinion of Counsel delivered to the
Trustee, such that the Trustee, on behalf of the Certificateholders has a claim
with respect to the funds in such accounts or a perfected first security
interest against any collateral securing such funds that is superior to claims
of any other depositors or creditors of the depository institution with which
such accounts are maintained, (iv) that are trust accounts maintained with the
trust department of a federal or state chartered depository institution or trust
company acting in its fiduciary capacity or (v) such other account that is
acceptable to each of the Rating Agencies and would not cause the Trust Estate
to fail to qualify as two separate REMICs or result in the imposition of any
federal tax on either of the Upper-Tier REMIC or the Lower-Tier REMIC.

      Eligible Investments: At any time, any one or more of the following
obligations and securities which shall mature not later than the Business Day
preceding the Distribution Date next succeeding the date of such investment,
provided that such investments continue to qualify as "cash flow investments" as
defined in Code Section 860G(a)(6):

            (i) obligations of the United States of America or any agency
      thereof, provided such obligations are backed by the full faith and credit
      of the United States of America;

            (ii) general obligations of or obligations guaranteed by any state
      of the United States of America or the District of Columbia receiving the
      highest short-term or highest long-term rating of each Rating Agency, or
      such lower rating as would not result in the downgrading or withdrawal of
      the rating then assigned to any of the Certificates by either Rating
      Agency or result in any of such rated Certificates being placed on credit
      review status (other than for possible upgrading) by any Rating Agency;

            (iii) commercial or finance company paper which is then rated in the
      highest long-term commercial or finance company paper rating category of
      each Rating Agency or the highest short-term rating category of each
      Rating Agency, or such lower rating category as would not result in the
      downgrading or withdrawal of the rating then assigned to any of the
      Certificates by either Rating Agency or result in any of such rated
      Certificates being placed on credit review status (other than for possible
      upgrading) by any Rating Agency;

            (iv) certificates of deposit, demand or time deposits, federal funds
      or banker's acceptances issued by any depository institution or trust
      company incorporated under the laws of the United States or of any state
      thereof and subject to supervision and examination by federal and/or state
      banking authorities, provided that the commercial paper and/or debt
      obligations of such depository institution or trust company (or in the
      case of the principal depository institution in a holding company system,
      the commercial paper or debt obligations of such holding company) are then
      rated in the highest short-term or the highest long-term rating category
      for such securities of each of the Rating Agencies, or such lower rating
      categories as would not result in the downgrading or withdrawal of the
      rating then assigned to any of the Certificates by either Rating Agency or
      result in any of such rated Certificates being placed on credit review
      status (other than for possible upgrading) by any Rating Agency;

            (v) guaranteed reinvestment agreements issued by any bank, insurance
      company or other corporation acceptable to each Rating Agency at the time
      of the issuance of such agreements;

            (vi) repurchase agreements on obligations with respect to any
      security described in clauses (i) or (ii) above or any other security
      issued or guaranteed by an agency or instrumentality of the United States
      of America, in either case entered into with a depository institution or
      trust company (acting as principal) described in (iv) above;

            (vii) securities (other than stripped bonds or stripped coupon
      securities) bearing interest or sold at a discount issued by any
      corporation incorporated under the laws of the United States of America or
      any state thereof which, at the time of such investment or contractual
      commitment providing for such investment, are then rated in the highest
      short-term or the highest long-term rating category by each Rating Agency,
      or in such lower rating category as would not result in the downgrading or
      withdrawal of the rating then assigned to any of the Certificates by
      either Rating Agency or result in any of such rated Certificates being
      placed on credit review status (other than for possible upgrading) by any
      Rating Agency;

            (viii) such other investments acceptable to each Rating Agency as
      would not result in the downgrading of the rating then assigned to the
      Certificates by either Rating Agency or result in any of such rated
      Certificates being placed on credit review status (other than for possible
      upgrading) by any Rating Agency; and

            (ix) any mutual fund, money market fund, common trust fund or other
      pooled investment vehicle, the assets of which are limited to instruments
      that otherwise would constitute Eligible Investments hereunder, including
      any such fund that is managed by the Trustee or Master Servicer or any
      affiliate of the Trustee or Master Servicer or for which the Trustee or
      Master Servicer or any of its affiliates acts as an adviser as long as
      such fund is rated in at least the highest rating category by each Rating
      Agency.

      In no event shall an instrument be an Eligible Investment if such
instrument evidences either (i) a right to receive only interest payments with
respect to the obligations underlying such instrument, or (ii) both principal
and interest payments derived from obligations underlying such instrument and
the interest and principal payments with respect to such instrument provide a
yield to maturity at the date of investment of greater than 120% of the yield to
maturity at par of such underlying obligations.

      ERISA: The Employee Retirement Income Security Act of 1974, as amended.

      ERISA Prohibited Holder: As defined in Section 5.02(d).

      Errors and Omissions Policy: As defined in each of the Servicing
Agreements.

      Event of Default: Any of the events specified in Section 7.01.

      Exchange Act: The Securities Exchange Act of 1934, as amended.

      FDIC: The Federal Deposit Insurance Corporation or any successor thereto.

      Fidelity Bond: As defined in each of the Servicing Agreements.

      Final Distribution Date: The Distribution Date on which the final
distribution in respect of the Certificates is made pursuant to Section 9.01.

      Final Scheduled Maturity Date: The Final Scheduled Maturity Date for each
Class of Class A Certificates and Class B Certificates is April 25, 2036, which
corresponds to the "latest possible maturity date" for purposes of Section
860G(a)(1) of the Internal Revenue Code of 1986, as amended.

      Fitch: Fitch Ratings, or its successor in interest.

      Fixed Retained Yield: The fixed percentage of interest on each Mortgage
Loan with a Mortgage Interest Rate greater than the sum of (a) 5.750%, (b) the
applicable Servicing Fee Rate and (c) the Master Servicing Fee Rate, which will
be determined on a loan by loan basis and will equal the Mortgage Interest Rate
on each Mortgage Loan minus the sum of the rates described above in clauses (a),
(b) and (c), which is not assigned to and not part of the Trust Estate.

      Fixed Retained Yield Rate: With respect to each Mortgage Loan, a per annum
rate equal to the greater of (a) zero and (b) the Mortgage Interest Rate on such
Mortgage Loan minus the sum of (a) 5.750%, (b) the applicable Servicing Fee Rate
and (c) the Master Servicing Fee Rate.

      Form 8-K: A Current Report on Form 8-K under the Exchange Act.

      Form 8-K Disclosure Information: As defined in Section 3.12(c).

      Form 10-D: An Asset-Backed Issuer Distribution Report on Form 10-D under
the Exchange Act.

      Form 10-K: An Annual Report on Form 10-K under the Exchange Act.

      Form 15: A Form 15 Suspension Notification under the Exchange Act.

      Full Unscheduled Principal Receipt: Any Unscheduled Principal Receipt with
respect to a Mortgage Loan (i) in the amount of the outstanding principal
balance of such Mortgage Loan and resulting in the full satisfaction of such
Mortgage Loan or (ii) representing Liquidation Proceeds other than Partial
Liquidation Proceeds.

      Grantor Trust: That portion of the Trust exclusive of the REMICs
consisting of (a) the right of the Class I-A-5 Certificates to receive amounts
from the Reserve Fund and (b) the Yield Maintenance Agreement and the Reserve
Fund.

      Group: Either of Group I or Group II.

      Group I: The Group I-A Certificates and Group I-B Certificates.

      Group I Adjusted Pool Amount: With respect to any Distribution Date, the
aggregate of the Cut-Off Date Principal Balances of the Group I Mortgage Loans
minus the sum of (i) all amounts in respect of principal received in respect of
the Group I Mortgage Loans (including, without limitation, amounts received as
Monthly Payments, Periodic Advances, Unscheduled Principal Receipts and
Substitution Principal Amounts) and distributed to Holders of the Certificates
on such Distribution Date and all prior Distribution Dates, (ii) the principal
portion of all Liquidated Loan Losses incurred on such Group I Mortgage Loans
for which the Liquidation Proceeds were received from the Cut-Off Date through
the end of the Applicable Unscheduled Principal Receipt Period with respect to
Full Unscheduled Principal Receipts for such Distribution Date and (iii) the
principal portion of all Bankruptcy Losses (other than Debt Service Reductions)
incurred on the Group I Mortgage Loans from the Cut-Off Date through the end of
the period corresponding to the Applicable Unscheduled Principal Receipt Period
with respect to Full Unscheduled Principal Receipts for such Distribution Date.

      Group I Adjusted Pool Amount (Non-PO Portion): With respect to any
Distribution Date, the difference between the Group I Adjusted Pool Amount and
the Group I Adjusted Pool Amount (PO Portion).

      Group I Adjusted Pool Amount (PO Portion): With respect to any
Distribution Date, the sum of the amounts, calculated as follows, with respect
to all Outstanding Mortgage Loans that are Group I Mortgage Loans: the product
of (i) the PO Fraction for each such Group I Mortgage Loan and (ii) the
remainder of (A) the Cut-Off Date Principal Balance of such Mortgage Loan minus
(B) the sum of (x) all amounts in respect of principal received in respect of
such Group I Mortgage Loan (including, without limitation, amounts received as
Monthly Payments, Periodic Advances, Unscheduled Principal Receipts and
Substitution Principal Amounts) and distributed to Holders of the Certificates
on such Distribution Date and all prior Distribution Dates, (y) the principal
portion of any Liquidated Loan Losses incurred on such Group I Mortgage Loans
for which Liquidation Proceeds were received from the Cut-Off Date through the
end of the Applicable Unscheduled Principal Receipt Period with respect to Full
Unscheduled Principal Receipts for such Distribution Date and (z) the principal
portion of all Bankruptcy Losses (other than Debt Service Reductions) incurred
on the Group I Mortgage Loans from the Cut-Off Date through the end of the
period corresponding to the Applicable Unscheduled Principal Receipt Period with
respect to Full Unscheduled Principal Receipts for such Distribution Date.

      Group I Aggregate Non-PO Principal Balance: The sum of the Group I-A
Non-PO Principal Balance and the Group I-B Principal Balance.

      Group I Class B Percentage: Any of the Group I Class I-B-1 Percentage,
Group I Class I-B-2 Percentage, Group I Class I-B-3 Percentage, Group I Class
I-B-4 Percentage, Group I Class I-B-5 Percentage or Group I Class I-B-6
Percentage.

      Group I Class B Prepayment Percentage: Any of the Group I Class I-B-1
Prepayment Percentage, Group I Class I-B-2 Prepayment Percentage, Group I Class
I-B-3 Prepayment Percentage, Group I Class I-B-4 Prepayment Percentage, Group I
Class I-B-5 Prepayment Percentage or Group I Class I-B-6 Prepayment Percentage.

      Group I Class I-B-1 Percentage: As to any Distribution Date, the
percentage calculated by multiplying the Group I Subordinated Percentage by
either (i) if any Group I-B Certificates (other than the Class I-B-1
Certificates) are eligible to receive principal distributions for such
Distribution Date in accordance with Section 4.01(d), a fraction, the numerator
of which is the Class I-B-1 Principal Balance (determined as of the
Determination Date preceding such Distribution Date) and the denominator of
which is the sum of the Principal Balances of the Classes of Group I-B
Certificates eligible to receive principal distributions for such Distribution
Date in accordance with the provisions of Section 4.01(d) or (ii) except as set
forth in Section 4.01(d)(ii), in the event that the Group I-B Certificates
(other than the Class I-B-1 Certificates) are not eligible to receive
distributions of principal in accordance with Section 4.01(d)(i), one.

      Group I Class I-B-1 Prepayment Percentage: As to any Distribution Date,
the percentage calculated by multiplying the Group I Subordinated Prepayment
Percentage by either (i) if any Group I-B Certificates (other than the Class
I-B-1 Certificates) are eligible to receive principal distributions for such
Distribution Date in accordance with Section 4.01(d), a fraction, the numerator
of which is the Class I-B-1 Principal Balance (determined as of the
Determination Date preceding such Distribution Date) and the denominator of
which is the sum of the Principal Balances of the Classes of Group I-B
Certificates eligible to receive principal distributions for such Distribution
Date in accordance with the provisions of Section 4.01(d) or (ii) except as set
forth in Section 4.01(d)(ii), in the event that the Group I-B Certificates
(other than the Class I-B-1 Certificates) are not eligible to receive
distributions of principal in accordance with Section 4.01(d)(i), one.

      Group I Class I-B-2 Percentage: As to any Distribution Date, except as set
forth in the next sentence, the percentage calculated by multiplying (i) the
Group I Subordinated Percentage by (ii) a fraction, the numerator of which is
the Class I-B-2 Principal Balance (determined as of the Determination Date
preceding such Distribution Date) and the denominator of which is the sum of the
Principal Balances of the Classes of Group I-B Certificates eligible to receive
principal distributions for such Distribution Date in accordance with the
provisions of Section 4.01(d). Except as set forth in Section 4.01(d)(ii), in
the event that the Class I-B-2 Certificates are not eligible to receive
distributions of principal in accordance with Section 4.01(d)(i), the Group I
Class I-B-2 Percentage for such Distribution Date will be zero.

      Group I Class I-B-2 Prepayment Percentage: As to any Distribution Date,
except as set forth in the next sentence, the percentage calculated by
multiplying (i) the Group I Subordinated Prepayment Percentage by (ii) a
fraction, the numerator of which is the Class I-B-2 Principal Balance
(determined as of the Determination Date preceding such Distribution Date) and
the denominator of which is the sum of the Principal Balances of the Classes of
Group I-B Certificates eligible to receive principal distributions for such
Distribution Date in accordance with the provisions of Section 4.01(d). Except
as set forth in Section 4.01(d)(ii), in the event that the Class I-B-2
Certificates are not eligible to receive distributions of principal in
accordance with Section 4.01(d)(i), the Group I Class I-B-2 Prepayment
Percentage for such Distribution Date will be zero.

      Group I Class I-B-3 Percentage: As to any Distribution Date, except as set
forth in the next sentence, the percentage calculated by multiplying (i) the
Group I Subordinated Percentage by (ii) a fraction, the numerator of which is
the Class I-B-3 Principal Balance (determined as of the Determination Date
preceding such Distribution Date) and the denominator of which is the sum of the
Principal Balances of the Classes of Group I-B Certificates eligible to receive
principal distributions for such Distribution Date in accordance with the
provisions of Section 4.01(d). Except as set forth in Section 4.01(d)(ii), in
the event that the Class I-B-3 Certificates are not eligible to receive
distributions of principal in accordance with Section 4.01(d)(i), the Group I
Class I-B-3 Percentage for such Distribution Date will be zero.

      Group I Class I-B-3 Prepayment Percentage: As to any Distribution Date,
except as set forth in the next sentence, the percentage calculated by
multiplying (i) the Group I Subordinated Prepayment Percentage by (ii) a
fraction, the numerator of which is the Class I-B-3 Principal Balance
(determined as of the Determination Date preceding such Distribution Date) and
the denominator of which is the sum of the Principal Balances of the Classes of
Group I-B Certificates eligible to receive principal distributions for such
Distribution Date in accordance with the provisions of Section 4.01(d). Except
as set forth in Section 4.01(d)(ii), in the event that the Class I-B-3
Certificates are not eligible to receive distributions of principal in
accordance with Section 4.01(d)(i), the Group I Class I-B-3 Prepayment
Percentage for such Distribution Date will be zero.

      Group I Class I-B-4 Percentage: As to any Distribution Date, except as set
forth in the next sentence, the percentage calculated by multiplying (i) the
Group I Subordinated Percentage by (ii) a fraction, the numerator of which is
the Class I-B-4 Principal Balance (determined as of the Determination Date
preceding such Distribution Date) and the denominator of which is the sum of the
Principal Balances of the Classes of Group I-B Certificates eligible to receive
principal distributions for such Distribution Date in accordance with the
provisions of Section 4.01(d). Except as set forth in Section 4.01(d)(ii), in
the event that the Class I-B-4 Certificates are not eligible to receive
distributions of principal in accordance with Section 4.01(d)(i), the Group I
Class I-B-4 Percentage for such Distribution Date will be zero.

      Group I Class I-B-4 Prepayment Percentage: As to any Distribution Date,
except as set forth in the next sentence, the percentage calculated by
multiplying (i) the Group I Subordinated Prepayment Percentage by (ii) a
fraction, the numerator of which is the Class I-B-4 Principal Balance
(determined as of the Determination Date preceding such Distribution Date) and
the denominator of which is the sum of the Principal Balances of the Classes of
Group I-B Certificates eligible to receive principal distributions for such
Distribution Date in accordance with the provisions of Section 4.01(d). Except
as set forth in Section 4.01(d)(ii), in the event that the Class I-B-4
Certificates are not eligible to receive distributions of principal in
accordance with Section 4.01(d)(i), the Group I Class I-B-4 Prepayment
Percentage for such Distribution Date will be zero.

      Group I Class I-B-5 Percentage: As to any Distribution Date, except as set
forth in the next sentence, the percentage calculated by multiplying (i) the
Group I Subordinated Percentage by (ii) a fraction, the numerator of which is
the Class I-B-5 Principal Balance (determined as of the Determination Date
preceding such Distribution Date) and the denominator of which is the sum of the
Principal Balances of the Classes of Group I-B Certificates eligible to receive
principal distributions for such Distribution Date in accordance with the
provisions of Section 4.01(d). Except as set forth in Section 4.01(d)(ii), in
the event that the Class I-B-5 Certificates are not eligible to receive
distributions of principal in accordance with Section 4.01(d)(i), the Group I
Class I-B-5 Percentage for such Distribution Date will be zero.

      Group I Class I-B-5 Prepayment Percentage: As to any Distribution Date,
except as set forth in the next sentence, the percentage calculated by
multiplying (i) the Group I Subordinated Prepayment Percentage by (ii) a
fraction, the numerator of which is the Class I-B-5 Principal Balance
(determined as of the Determination Date preceding such Distribution Date) and
the denominator of which is the sum of the Principal Balances of the Classes of
Group I-B Certificates eligible to receive principal distributions for such
Distribution Date in accordance with the provisions of Section 4.01(d). Except
as set forth in Section 4.01(d)(ii), in the event that the Class I-B-5
Certificates are not eligible to receive distributions of principal in
accordance with Section 4.01(d)(i), the Group I Class I-B-5 Prepayment
Percentage for such Distribution Date will be zero.

      Group I Class I-B-6 Percentage: As to any Distribution Date, except as set
forth in the next sentence, the percentage calculated by multiplying (i) the
Group I Subordinated Percentage by (ii) a fraction, the numerator of which is
the Class I-B-6 Principal Balance (determined as of the Determination Date
preceding such Distribution Date) and the denominator of which is the sum of the
Principal Balances of the Classes of Group I-B Certificates eligible to receive
principal distributions for such Distribution Date in accordance with the
provisions of Section 4.01(d). Except as set forth in Section 4.01(d)(ii), in
the event that the Class I-B-6 Certificates are not eligible to receive
distributions of principal in accordance with Section 4.01(d)(i), the Group I
Class I-B-6 Percentage for such Distribution Date will be zero.

      Group I Class I-B-6 Prepayment Percentage: As to any Distribution Date,
except as set forth in the next sentence, the percentage calculated by
multiplying (i) the Group I Subordinated Prepayment Percentage by (ii) a
fraction, the numerator of which is the Class I-B-6 Principal Balance
(determined as of the Determination Date preceding such Distribution Date) and
the denominator of which is the sum of the Principal Balances of the Classes of
Group I-B Certificates eligible to receive principal distributions for such
Distribution Date in accordance with the provisions of Section 4.01(d). Except
as set forth in Section 4.01(d)(ii), in the event that the Class I-B-6
Certificates are not eligible to receive distributions of principal in
accordance with Section 4.01(d)(i), the Group I Class I-B-6 Prepayment
Percentage for such Distribution Date will be zero.

      Group I Discount Mortgage Loan: A Group I Mortgage Loan with a Net
Mortgage Interest Rate of less than 5.750%.

      Group I Mortgage Loans: Those Mortgage Loans identified in the Mortgage
Loan Schedule as Group I Mortgage Loans.

      Group I Pool Balance (Non-PO Portion): As of any Distribution Date, the
sum of the amounts for each Group I Mortgage Loan that is an Outstanding
Mortgage Loan of the product of (i) the Non-PO Fraction for such Mortgage Loan
and (ii) the Scheduled Principal Balance of such Mortgage Loan.

      Group I Pool Balance (PO Portion): As of any Distribution Date, the sum of
the amounts for each Group I Mortgage Loan that is an Outstanding Mortgage Loan
of the product of (i) the PO Fraction for such Mortgage Loan and (ii) the
Scheduled Principal Balance of such Mortgage Loan.

      Group I Pool Distribution Amount: As of any Distribution Date, the funds
eligible for distribution to the Group I-A Certificates and Group I-B
Certificates on such Distribution Date, which shall be the sum of (i) all
previously undistributed payments or other receipts on account of principal and
interest on or in respect of the Group I Mortgage Loans (including, without
limitation, the proceeds of any repurchase of a Group I Mortgage Loan by the
Depositor and any Substitution Principal Amount) received by the Master Servicer
with respect to the applicable Remittance Date in the month of such Distribution
Date and any Unscheduled Principal Receipts received by the Master Servicer on
or prior to the Business Day preceding such Distribution Date, (ii) all Periodic
Advances made with respect to Group I Mortgage Loans by a Servicer pursuant to
the related Servicing Agreement or Periodic Advances with respect to Group I
Mortgage Loans made by the Master Servicer or the Trustee pursuant to Section
3.03, (iii) any remaining Reimbursement Amount with respect to a Group I
Mortgage Loan as provided in Section 4.01(a)(ii) and (iv) all other amounts
(including any Insurance Proceeds and Compensating Interest) with respect to a
Group I Mortgage Loan required to be placed in the Certificate Account by the
Servicer on or before the applicable Remittance Date or by the Master Servicer
or the Trustee on or prior to the Distribution Date, but excluding the
following:

            (a) amounts received as late payments of principal or interest with
      respect to a Group I Mortgage Loan and respecting which the Master
      Servicer or the Trustee has made one or more unreimbursed Periodic
      Advances;

            (b) the portion of Liquidation Proceeds used to reimburse any
      unreimbursed Periodic Advances with respect to a Group I Mortgage Loan by
      the Master Servicer or the Trustee;

            (c) that portion of each payment of interest on a particular Group I
      Mortgage Loan which represents (i) the Fixed Retained Yield, if any, (ii)
      the applicable Servicing Fee and (iii) the Master Servicing Fee;

            (d) all amounts representing scheduled payments of principal and
      interest on Group I Mortgage Loans due after the Due Date occurring in the
      month in which such Distribution Date occurs;

            (e) all Unscheduled Principal Receipts received by the Servicers
      with respect to Group I Mortgage Loans after the Applicable Unscheduled
      Principal Receipt Period relating to the Distribution Date for the
      applicable type of Unscheduled Principal Receipt, and all related payments
      of interest on such amounts;

            (f) all repurchase proceeds with respect to Group I Mortgage Loans
      repurchased by the Depositor pursuant to Section 2.02, 2.03 or 3.08 on or
      following the Determination Date in the month in which such Distribution
      Date occurs and the Substitution Principal Amounts with respect to any
      Group I Mortgage Loans for which Group I Mortgage Loans were substituted
      on or following the Determination Date in the month in which such
      Distribution Date occurs;

            (g) that portion of Liquidation Proceeds and REO Proceeds with
      respect to any Group I Mortgage Loan which represents (i) the Fixed
      Retained Yield, if any, (ii) the applicable Servicing Fee and (iii) the
      Master Servicing Fee;

            (h) all income from Eligible Investments that is held in the
      Certificate Account for the account of the Master Servicer;

            (i) Liquidation Profits in respect of Group I Mortgage Loans;

            (j) Month End Interest in respect of Group I Mortgage Loans;

            (k) all amounts reimbursable to a Servicer for PMI Advances in
      respect of Group I Mortgage Loans; and

            (l) all other amounts permitted to be withdrawn from the Certificate
      Account, to the extent not covered by clauses (a) through (k) above, or
      not required to be deposited in the Certificate Account under this
      Agreement.

      Group I Pool Scheduled Principal Balance: As to any Distribution Date, the
aggregate Scheduled Principal Balance of all Group I Mortgage Loans that were
Outstanding Mortgage Loans on the Due Date in the month preceding the month of
such Distribution Date.

      Group I Subordinated Percentage: As to any Distribution Date, the
percentage which is the difference between 100% and the Group I-A Percentage for
such date.

      Group I Subordinated Prepayment Percentage: As to any Distribution Date,
the percentage which is the difference between 100% and the Group I-A Prepayment
Percentage for such date.

      Group II: The Group II-A Certificates and Group II-B Certificates.

      Group II Adjusted Pool Amount: With respect to any Distribution Date, the
aggregate of the Cut-Off Date Principal Balances of the Group II Mortgage Loans
minus the sum of (i) all amounts in respect of principal received in respect of
the Group II Mortgage Loans (including, without limitation, amounts received as
Monthly Payments, Periodic Advances, Unscheduled Principal Receipts and
Substitution Principal Amounts) and distributed to Holders of the Certificates
on such Distribution Date and all prior Distribution Dates, (ii) the principal
portion of all Liquidated Loan Losses incurred on such Group II Mortgage Loans
for which the Liquidation Proceeds were received from the Cut-Off Date through
the end of Applicable Unscheduled Principal Receipt Period with respect to Full
Unscheduled Principal Receipts for such Distribution Date and (iii) the
principal portion of all Bankruptcy Losses (other than Debt Service Reductions)
incurred on the Group II Mortgage Loans from the Cut-Off Date through the end of
the period corresponding to the Applicable Unscheduled Principal Receipt Period
with respect to Full Unscheduled Principal Receipts for such Distribution Date.

      Group II Adjusted Pool Amount (Non-PO Portion): With respect to any
Distribution Date, the difference between the Group II Adjusted Pool Amount and
the Group II Adjusted Pool Amount (PO Portion).

      Group II Adjusted Pool Amount (PO Portion): With respect to any
Distribution Date, the sum of the amounts, calculated as follows, with respect
to all Outstanding Mortgage Loans that are Group II Mortgage Loans: the product
of (i) the PO Fraction for each such Group II Mortgage Loan and (ii) the
remainder of (A) the Cut-Off Date Principal Balance of such Mortgage Loan minus
(B) the sum of (x) all amounts in respect of principal received in respect of
such Group II Mortgage Loan (including, without limitation, amounts received as
Monthly Payments, Periodic Advances, Unscheduled Principal Receipts and
Substitution Principal Amounts) and distributed to Holders of the Certificates
on such Distribution Date and all prior Distribution Dates, (y) the principal
portion of any Liquidated Loan Losses incurred on such Group II Mortgage Loans
for which Liquidation Proceeds were received from the Cut-Off Date through the
end of the Applicable Unscheduled Principal Receipt Period with respect to Full
Unscheduled Principal Receipts for such Distribution Date and (z) the principal
portion of all Bankruptcy Losses (other than Debt Service Reductions) incurred
on the Group II Mortgage Loans from the Cut-Off Date through the end of the
period corresponding to the Applicable Unscheduled Principal Receipt Period with
respect to Full Unscheduled Principal Receipts for such Distribution Date.

      Group II Aggregate Non-PO Principal Balance: The sum of the Group II-A
Non-PO Principal Balance and the Group II-B Principal Balance.

      Group II Class B Percentage: Any one of the Group II Class II-B-1
Percentage, Group II Class II-B-2 Percentage, Group II Class II-B-3 Percentage,
Group II Class II-B-4 Percentage, Group II Class II-B-5 Percentage or Group II
Class II-B-6 Percentage.

      Group II Class B Prepayment Percentage: Any of the Group II Class II-B-1
Prepayment Percentage, Group II Class II-B-2 Prepayment Percentage, Group II
Class II-B-3 Prepayment Percentage, Group II Class II-B-4 Prepayment Percentage,
Group II Class II-B-5 Prepayment Percentage or Group II Class II-B-6 Prepayment
Percentage.

      Group II Class II-B-1 Percentage: As to any Distribution Date, the
percentage calculated by multiplying the Group II Subordinated Percentage by
either (i) if any Group II-B Certificates (other than the Class II-B-1
Certificates) are eligible to receive principal distributions for such
Distribution Date in accordance with Section 4.01(d), a fraction, the numerator
of which is the Class II-B-1 Principal Balance (determined as of the
Determination Date preceding such Distribution Date) and the denominator of
which is the sum of the Principal Balances of the Classes of Group II-B
Certificates eligible to receive principal distributions for such Distribution
Date in accordance with the provisions of Section 4.01(d) or (ii) except as set
forth in Section 4.01(d)(ii), in the event that the Group II-B Certificates
(other than the Class II-B-1 Certificates) are not eligible to receive
distributions of principal in accordance with Section 4.01(d)(i), one.

      Group II Class II-B-1 Prepayment Percentage: As to any Distribution Date,
the percentage calculated by multiplying the Group II Subordinated Prepayment
Percentage by either (i) if any Group II-B Certificates (other than the Class
II-B-1 Certificates) are eligible to receive principal distributions for such
Distribution Date in accordance with Section 4.01(d), a fraction, the numerator
of which is the Class II-B-1 Principal Balance (determined as of the
Determination Date preceding such Distribution Date) and the denominator of
which is the sum of the Principal Balances of the Classes of Group II-B
Certificates eligible to receive principal distributions for such Distribution
Date in accordance with the provisions of Section 4.01(d) or (ii) except as set
forth in Section 4.01(d)(ii), in the event that the Group II-B Certificates
(other than the Class II-B-1 Certificates) are not eligible to receive
distributions of principal in accordance with Section 4.01(d)(i), one.

      Group II Class II-B-2 Percentage: As to any Distribution Date, except as
set forth in the next sentence, the percentage calculated by multiplying (i) the
Group II Subordinated Percentage by (ii) a fraction, the numerator of which is
the Class II-B-2 Principal Balance (determined as of the Determination Date
preceding such Distribution Date) and the denominator of which is the sum of the
Principal Balances of the Classes of Group II-B Certificates eligible to receive
principal distributions for such Distribution Date in accordance with the
provisions of Section 4.01(d). Except as set forth in Section 4.01(d)(ii), in
the event that the Class II-B-2 Certificates are not eligible to receive
distributions of principal in accordance with Section 4.01(d)(i), the Group II
Class II-B-2 Percentage for such Distribution Date will be zero.

      Group II Class II-B-2 Prepayment Percentage: As to any Distribution Date,
except as set forth in the next sentence, the percentage calculated by
multiplying (i) the Group II Subordinated Prepayment Percentage by (ii) a
fraction, the numerator of which is the Class II-B-2 Principal Balance
(determined as of the Determination Date preceding such Distribution Date) and
the denominator of which is the sum of the Principal Balances of the Classes of
Group II-B Certificates eligible to receive principal distributions for such
Distribution Date in accordance with the provisions of Section 4.01(d). Except
as set forth in Section 4.01(d)(ii), in the event that the Class II-B-2
Certificates are not eligible to receive distributions of principal in
accordance with Section 4.01(d)(i), the Group II Class II-B-2 Prepayment
Percentage for such Distribution Date will be zero.

      Group II Class II-B-3 Percentage: As to any Distribution Date, except as
set forth in the next sentence, the percentage calculated by multiplying (i) the
Group II Subordinated Percentage by (ii) a fraction, the numerator of which is
the Class II-B-3 Principal Balance (determined as of the Determination Date
preceding such Distribution Date) and the denominator of which is the sum of the
Principal Balances of the Classes of Group II-B Certificates eligible to receive
principal distributions for such Distribution Date in accordance with the
provisions of Section 4.01(d). Except as set forth in Section 4.01(d)(ii), in
the event that the Class II-B-3 Certificates are not eligible to receive
distributions of principal in accordance with Section 4.01(d)(i), the Group II
Class II-B-3 Percentage for such Distribution Date will be zero.

      Group II Class II-B-3 Prepayment Percentage: As to any Distribution Date,
except as set forth in the next sentence, the percentage calculated by
multiplying (i) the Group II Subordinated Prepayment Percentage by (ii) a
fraction, the numerator of which is the Class II-B-3 Principal Balance
(determined as of the Determination Date preceding such Distribution Date) and
the denominator of which is the sum of the Principal Balances of the Classes of
Group II-B Certificates eligible to receive principal distributions for such
Distribution Date in accordance with the provisions of Section 4.01(d). Except
as set forth in Section 4.01(d)(ii), in the event that the Class II-B-3
Certificates are not eligible to receive distributions of principal in
accordance with Section 4.01(d)(i), the Group II Class II-B-3 Prepayment
Percentage for such Distribution Date will be zero.

      Group II Class II-B-4 Percentage: As to any Distribution Date, except as
set forth in the next sentence, the percentage calculated by multiplying (i) the
Group II Subordinated Percentage by (ii) a fraction, the numerator of which is
the Class II-B-4 Principal Balance (determined as of the Determination Date
preceding such Distribution Date) and the denominator of which is the sum of the
Principal Balances of the Classes of Group II-B Certificates eligible to receive
principal distributions for such Distribution Date in accordance with the
provisions of Section 4.01(d). Except as set forth in Section 4.01(d)(ii), in
the event that the Class II-B-4 Certificates are not eligible to receive
distributions of principal in accordance with Section 4.01(d)(i), the Group II
Class II-B-4 Percentage for such Distribution Date will be zero.

      Group II Class II-B-4 Prepayment Percentage: As to any Distribution Date,
except as set forth in the next sentence, the percentage calculated by
multiplying (i) the Group II Subordinated Prepayment Percentage by (ii) a
fraction, the numerator of which is the Class II-B-4 Principal Balance
(determined as of the Determination Date preceding such Distribution Date) and
the denominator of which is the sum of the Principal Balances of the Classes of
Group II-B Certificates eligible to receive principal distributions for such
Distribution Date in accordance with the provisions of Section 4.01(d). Except
as set forth in Section 4.01(d)(ii), in the event that the Class II-B-4
Certificates are not eligible to receive distributions of principal in
accordance with Section 4.01(d)(i), the Group II Class II-B-4 Prepayment
Percentage for such Distribution Date will be zero.

      Group II Class II-B-5 Percentage: As to any Distribution Date, except as
set forth in the next sentence, the percentage calculated by multiplying (i) the
Group II Subordinated Percentage by (ii) a fraction, the numerator of which is
the Class II-B-5 Principal Balance (determined as of the Determination Date
preceding such Distribution Date) and the denominator of which is the sum of the
Principal Balances of the Classes of Group II-B Certificates eligible to receive
principal distributions for such Distribution Date in accordance with the
provisions of Section 4.01(d). Except as set forth in Section 4.01(d)(ii), in
the event that the Class II-B-5 Certificates are not eligible to receive
distributions of principal in accordance with Section 4.01(d)(i), the Group II
Class II-B-5 Percentage for such Distribution Date will be zero.

      Group II Class II-B-5 Prepayment Percentage: As to any Distribution Date,
except as set forth in the next sentence, the percentage calculated by
multiplying (i) the Group II Subordinated Prepayment Percentage by (ii) a
fraction, the numerator of which is the Class II-B-5 Principal Balance
(determined as of the Determination Date preceding such Distribution Date) and
the denominator of which is the sum of the Principal Balances of the Classes of
Group II-B Certificates eligible to receive principal distributions for such
Distribution Date in accordance with the provisions of Section 4.01(d). Except
as set forth in Section 4.01(d)(ii), in the event that the Class II-B-5
Certificates are not eligible to receive distributions of principal in
accordance with Section 4.01(d)(i), the Group II Class II-B-5 Prepayment
Percentage for such Distribution Date will be zero.

      Group II Class II-B-6 Percentage: As to any Distribution Date, except as
set forth in the next sentence, the percentage calculated by multiplying (i) the
Group II Subordinated Percentage by (ii) a fraction, the numerator of which is
the Class II-B-6 Principal Balance (determined as of the Determination Date
preceding such Distribution Date) and the denominator of which is the sum of the
Principal Balances of the Classes of Group II-B Certificates eligible to receive
principal distributions for such Distribution Date in accordance with the
provisions of Section 4.01(d). Except as set forth in Section 4.01(d)(ii), in
the event that the Class II-B-6 Certificates are not eligible to receive
distributions of principal in accordance with Section 4.01(d)(i), the Group II
Class II-B-6 Percentage for such Distribution Date will be zero.

      Group II Class II-B-6 Prepayment Percentage: As to any Distribution Date,
except as set forth in the next sentence, the percentage calculated by
multiplying (i) the Group II Subordinated Prepayment Percentage by (ii) a
fraction, the numerator of which is the Class II-B-6 Principal Balance
(determined as of the Determination Date preceding such Distribution Date) and
the denominator of which is the sum of the Principal Balances of the Classes of
Group II-B Certificates eligible to receive principal distributions for such
Distribution Date in accordance with the provisions of Section 4.01(d). Except
as set forth in Section 4.01(d)(ii), in the event that the Class II-B-6
Certificates are not eligible to receive distributions of principal in
accordance with Section 4.01(d)(i), the Group II Class II-B-6 Prepayment
Percentage for such Distribution Date will be zero.

      Group II Discount Mortgage Loan: A Group II Mortgage Loan with a Net
Mortgage Interest Rate of less than 5.750%.

      Group II Mortgage Loans: Those Mortgage Loans identified in the Mortgage
Loan Schedule as Group II Mortgage Loans.

      Group II Pool Balance (Non-PO Portion): As of any Distribution Date, the
sum of the amounts for each Group II Mortgage Loan that is an Outstanding
Mortgage Loan of the product of (i) the Non-PO Fraction for such Mortgage Loan
and (ii) the Scheduled Principal Balance of such Mortgage Loan.

      Group II Pool Balance (PO Portion): As of any Distribution Date, the sum
of the amounts for each Group II Mortgage Loan that is an Outstanding Mortgage
Loan of the product of (i) the PO Fraction for such Mortgage Loan and (ii) the
Scheduled Principal Balance of such Mortgage Loan.

      Group II Pool Distribution Amount: As of any Distribution Date, the funds
eligible for distribution to the Group II-A Certificates and Group II-B
Certificates on such Distribution Date, which shall be the sum of (i) all
previously undistributed payments or other receipts on account of principal and
interest on or in respect of the Group II Mortgage Loans (including, without
limitation, the proceeds of any repurchase of a Group II Mortgage Loan by the
Depositor and any Substitution Principal Amount) received by the Master Servicer
with respect to the applicable Remittance Date in the month of such Distribution
Date and any Unscheduled Principal Receipts received by the Master Servicer on
or prior to the Business Day preceding such Distribution Date, (ii) all Periodic
Advances made with respect to Group II Mortgage Loans by a Servicer pursuant to
the related Servicing Agreement or Periodic Advances with respect to Group II
Mortgage Loans made by the Master Servicer or the Trustee pursuant to Section
3.03, (iii) any remaining Reimbursement Amount with respect to a Group II
Mortgage Loan as provided in Section 4.01(a)(ii) and (iv) all other amounts
(including any Insurance Proceeds and Compensating Interest) with respect to a
Group II Mortgage Loan required to be placed in the Certificate Account by the
Servicer on or before the applicable Remittance Date or by the Master Servicer
or the Trustee on or prior to the Distribution Date, but excluding the
following:

            (a) amounts received as late payments of principal or interest with
      respect to a Group II Mortgage Loan and respecting which the Master
      Servicer or the Trustee has made one or more unreimbursed Periodic
      Advances;

            (b) the portion of Liquidation Proceeds used to reimburse any
      unreimbursed Periodic Advances with respect to a Group II Mortgage Loan by
      the Master Servicer or the Trustee;

            (c) that portion of each payment of interest on a particular Group
      II Mortgage Loan which represents (i) the Fixed Retained Yield, if any,
      (ii) the applicable Servicing Fee and (iii) the Master Servicing Fee;

            (d) all amounts representing scheduled payments of principal and
      interest on Group II Mortgage Loans due after the Due Date occurring in
      the month in which such Distribution Date occurs;

            (e) all Unscheduled Principal Receipts received by the Servicers
      with respect to Group II Mortgage Loans after the Applicable Unscheduled
      Principal Receipt Period relating to the Distribution Date for the
      applicable type of Unscheduled Principal Receipt, and all related payments
      of interest on such amounts;

            (f) all repurchase proceeds with respect to Group II Mortgage Loans
      repurchased by the Depositor pursuant to Section 2.02, 2.03 or 3.08 on or
      following the Determination Date in the month in which such Distribution
      Date occurs and the Substitution Principal Amounts with respect to any
      Group II Mortgage Loans for which Group II Mortgage Loans were substituted
      on or following the Determination Date in the month in which such
      Distribution Date occurs;

            (g) that portion of Liquidation Proceeds and REO Proceeds with
      respect to any Group II Mortgage Loan which represents (i) the Fixed
      Retained Yield, if any, (ii) the applicable Servicing Fee and (iii) the
      Master Servicing Fee;

            (h) all income from Eligible Investments that is held in the
      Certificate Account for the account of the Master Servicer;

            (i) Liquidation Profits in respect of Group II Mortgage Loans;

            (j) Month End Interest in respect of Group II Mortgage Loans;

            (k) all amounts reimbursable to a Servicer for PMI Advances in
      respect of Group II Mortgage Loans; and

            (l) all other amounts permitted to be withdrawn from the Certificate
      Account in respect of the Group II Mortgage Loans, to the extent not
      covered by clauses (a) through (k) above, or not required to be deposited
      in the Certificate Account under this Agreement.

      Group II Pool Scheduled Principal Balance: As to any Distribution Date,
the aggregate Scheduled Principal Balance of all Group II Mortgage Loans that
were Outstanding Mortgage Loans on the Due Date in the month preceding the month
of such Distribution Date.

      Group II Subordinated Percentage: As to any Distribution Date, the
percentage which is the difference between 100% and the Group II-A Percentage
for such date.

      Group II Subordinated Prepayment Percentage: As to any Distribution Date,
the percentage which is the difference between 100% and the Group II-A
Prepayment Percentage for such date.

      Group I-A Certificate: Any Class I-A-1, Class I-A-2, Class I-A-3, Class
I-A-4, Class I-A-5, Class I-A-6, Class I-A-7, Class I-A-8, Class I-A-9, Class
I-A-10, Class I-A-11, Class I-A-12, Class I-A-13, Class I-A-14, Class I-A-R or
Class I-A-PO Certificate.

      Group I-A Distribution Amount: As to any Distribution Date and any Class
of Group I-A Certificates (other than the Classes of Accrual Certificates and
the Class I-A-6 and Class I-A-PO Certificates), the amount distributable to such
Class of Group I-A Certificates pursuant to Paragraphs first clause (A), second
clause (A) and third clause (A)(1) of Section 4.01(a)(i). As to a Class of
Accrual Certificates, (a) as to any Distribution Date prior to the applicable
Accretion Termination Date, the amount distributable to such Class of Accrual
Certificates pursuant to the provisos in Paragraphs first clause (A) and second
clause (A) of Section 4.01(a)(i) and Paragraph third clause (A)(1) of Section
4.01(a)(i) and (b) as to any Distribution Date on or after the applicable
Accretion Termination Date, the amount distributable to such Class of Accrual
Certificates pursuant to Paragraphs first clause (A), second clause (A) and
third clause (A)(1) of Section 4.01(a)(i). As to any Distribution Date and the
Class I-A-6 Certificates, the amount distributable to such Class pursuant to
Paragraphs first clause (A) and second clause (A) of Section 4.01(a)(i). As to
any Distribution Date and the Class I-A-PO Certificates, the amount
distributable to the Class I-A-PO Certificates pursuant to Paragraphs third
clause (A)(2) and fourth clause (A) of Section 4.01(a)(i) on such Distribution
Date.

      Group I-A Interest Accrual Amount: As to any Distribution Date, the sum of
the Interest Accrual Amounts for the Group I-A Certificates with respect to such
Distribution Date.

      Group I-A Interest Percentage: As to any Distribution Date and any Class
of Group I-A Certificates, the percentage calculated by dividing the Interest
Accrual Amount of such Class (determined without regard to clause (ii) of the
definition thereof) by the Group I-A Interest Accrual Amount (determined without
regard to clause (ii) of the definition of each Interest Accrual Amount).

      Group I-A Interest Shortfall Amount: As to any Distribution Date and any
Class of Group I-A Certificates, any amount by which the Interest Accrual Amount
of such Class with respect to such Distribution Date exceeds the amount
distributed in respect of such Class on such Distribution Date pursuant to
Paragraph first clause (A) of Section 4.01(a)(i), including, in the case of a
Class of Accrual Certificates prior to the applicable Accretion Termination
Date, the amount included in the Accrual Distribution Amount pursuant to clause
(i) of the definition thereof.

      Group I-A Interest Shortfall Percentage: As to any Distribution Date and
any Class of Group I-A Certificates, the percentage calculated by dividing the
Class A Unpaid Interest Shortfall for such Class by the Aggregate Group I-A
Unpaid Interest Shortfall, in each case determined as of the day preceding the
applicable Distribution Date.

      Group I-A Loss Denominator: As to any Determination Date, an amount equal
to the sum of (i) the Group I-A Non-PO Principal Balance (less the Principal
Balances of the Classes of Accrual Certificates) and (ii) with respect to a
Class of Accrual Certificates, the lesser of the Principal Balance of such Class
of Accrual Certificates and the Original Principal Balance of such Class of
Accrual Certificates.

      Group I-A Loss Percentage: As to any Determination Date and any Class of
Group I-A Certificates, the percentage calculated by dividing the Principal
Balance of such Class (or, in the case of a Class of Accrual Certificates, the
Original Principal Balance of such Class of Accrual Certificates, if lower) by
the Group I-A Loss Denominator (determined without regard to any such Principal
Balance of any Class of Group I-A Certificates not then outstanding), in each
case determined as of the preceding Determination Date.

      Group I-A Non-PO Optimal Amount: As to any Distribution Date, the sum for
such Distribution Date of (i) the Group I-A Interest Accrual Amount, (ii) the
Aggregate Group I-A Unpaid Interest Shortfall and (iii) the Group I-A Non-PO
Optimal Principal Amount.

      Group I-A Non-PO Optimal Principal Amount: As to any Distribution Date, an
amount equal to the sum of (I) the sum, as to each Group I Mortgage Loan that is
an Outstanding Mortgage Loan, of the product of (x) the Non-PO Fraction with
respect to such Mortgage Loan, and (y) the sum of:

            (i) the Group I-A Percentage of the principal portion of the Monthly
      Payment due on the Due Date occurring in the month of such Distribution
      Date on such Mortgage Loan;

            (ii) the Group I-A Prepayment Percentage of all Unscheduled
      Principal Receipts (other than Recoveries) that were received by a
      Servicer with respect to such Mortgage Loan during the Applicable
      Unscheduled Principal Receipt Period relating to such Distribution Date
      for each applicable type of Unscheduled Principal Receipt;

            (iii) the Group I-A Prepayment Percentage of the Scheduled Principal
      Balance of such Mortgage Loan which, during the one month period ending on
      the day preceding the Determination Date for such Distribution Date, was
      repurchased by the Depositor pursuant to Section 2.02, 2.03 or 3.08; and

            (iv) the Group I-A Percentage of the Substitution Principal Amount
      with respect to each Mortgage Loan for which a Mortgage Loan was
      substituted during the one month period ending on the day preceding the
      Determination Date for such Distribution Date, less the amount allocable
      to the principal portion of any unreimbursed Periodic Advances previously
      made by the applicable Servicer, the Master Servicer or the Trustee in
      respect of such Mortgage Loan for which a Mortgage Loan was substituted;
      and

      (II) the Group I-A Prepayment Percentage of the Non-PO Recovery for Loan
      Group I for such Distribution Date.

      Group I-A Non-PO Principal Balance: As of any date, an amount equal to the
Group I-A Principal Balance less the Principal Balance of the Class I-A-PO
Certificates.

      Group I-A Non-PO Principal Distribution Amount: As to any Distribution
Date, the aggregate amount distributed in respect of the Classes of Group I-A
Certificates pursuant to Paragraph third clause (A)(1) of Section 4.01(a)(i).

      Group I-A Percentage: As to any Distribution Date occurring on or prior to
the applicable Subordination Depletion Date, the lesser of (i) 100% and (ii) the
percentage obtained by dividing the Group I-A Non-PO Principal Balance
(determined as of the Determination Date preceding such Distribution Date) by
the Group I Pool Balance (Non-PO Portion). As to any Distribution Date occurring
subsequent to the applicable Subordination Depletion Date, 100% or such lesser
percentage which will cause the Group I-A Non-PO Principal Balance to decline to
zero following the distribution made on such Distribution Date.

      Group I-A Prepayment Percentage: As to any Distribution Date to and
including the Distribution Date in March 2011, 100%. As to any Distribution Date
subsequent to March 2011 to and including the Distribution Date in March 2012,
the Group I-A Percentage as of such Distribution Date plus 70% of the Group I
Subordinated Percentage as of such Distribution Date. As to any Distribution
Date subsequent to March 2012 to and including the Distribution Date in March
2013, the Group I-A Percentage as of such Distribution Date plus 60% of the
Group I Subordinated Percentage as of such Distribution Date. As to any
Distribution Date subsequent to March 2013 to and including the Distribution
Date in March 2014, the Group I-A Percentage as of such Distribution Date plus
40% of the Group I Subordinated Percentage as of such Distribution Date. As to
any Distribution Date subsequent to March 2014 to and including the Distribution
Date in March 2015, the Group I-A Percentage as of such Distribution Date plus
20% of the Group I Subordinated Percentage as of such Distribution Date. As to
any Distribution Date subsequent to March 2015, the Group I-A Percentage as of
such Distribution Date. The foregoing is subject to the following: (i) if the
aggregate distribution to Holders of Group I-A Certificates on any Distribution
Date of the Group I-A Prepayment Percentage provided above of Unscheduled
Principal Receipts distributable on such Distribution Date would reduce the
Group I-A Non-PO Principal Balance below zero, the Group I-A Prepayment
Percentage for such Distribution Date shall be the percentage necessary to bring
the Group I-A Non-PO Principal Balance to zero and thereafter the Group I-A
Prepayment Percentage shall be zero and (ii) if the Group I-A Percentage as of
any Distribution Date is greater than the Original Group I-A Percentage, the
Group I-A Prepayment Percentage for such Distribution Date shall be 100%.
Notwithstanding the foregoing, with respect to any Distribution Date on which
the following criteria are not met, the reduction of the Group I-A Prepayment
Percentage described in the second through sixth sentences of this definition of
Group I-A Prepayment Percentage shall not be applicable with respect to such
Distribution Date. In such event, the Group I-A Prepayment Percentage for such
Distribution Date will be determined in accordance with the applicable
provision, as set forth in the first through fifth sentences above, which was
actually used to determine the Group I-A Prepayment Percentage for the
Distribution Date occurring in the March preceding such Distribution Date (it
being understood that for the purposes of the determination of the Group I-A
Prepayment Percentage for the current Distribution Date, the current Group I-A
Percentage and Group I Subordinated Percentage shall be utilized).

      No reduction in the Group I-A Prepayment Percentage referred to in the
second through sixth sentences hereof shall be applicable, with respect to any
Distribution Date if (a) the average outstanding principal balance on such
Distribution Date and for the preceding five Distribution Dates on the Group I
Mortgage Loans that were delinquent 60 days or more (including for this purpose
any payments due with respect to Mortgage Loans in foreclosure and REO Mortgage
Loans) were greater than or equal to 50% of the Group I-B Principal Balance or
(b) cumulative Realized Losses on the Group I Mortgage Loans exceed (1) 30% of
the Original Group I Subordinated Principal Balance if such Distribution Date
occurs between and including April 2011 and March 2012, (2) 35% of the Original
Group I Subordinated Principal Balance if such Distribution Date occurs between
and including April 2012 and March 2013, (3) 40% of the Original Group I
Subordinated Principal Balance if such Distribution Date occurs between and
including April 2013 and March 2014, (4) 45% of the Original Group I
Subordinated Principal Balance if such Distribution Date occurs between and
including April 2014 and March 2015, and (5) 50% of the Original Group I
Subordinated Principal Balance if such Distribution Date occurs during or after
April 2015. With respect to any Distribution Date on which the Group I-A
Prepayment Percentage is reduced below the Group I-A Prepayment Percentage for
the prior Distribution Date, the Master Servicer shall certify to the Trustee,
based upon information provided by each Servicer as to the Mortgage Loans
serviced by it that the criteria set forth in the preceding sentence are met.

      Group I-A Principal Balance: As of any date, an amount equal to the sum of
the Principal Balances for the Group I-A Certificates.

      Group I-B Certificate: Any one of the Class I-B-1 Certificates, Class
I-B-2 Certificates, Class I-B-3 Certificates, Class I-B-4 Certificates, Class
I-B-5 Certificates or Class I-B-6 Certificates.

      Group I-B Principal Balance: As of any date, an amount equal to the sum of
the Class I-B-1 Principal Balance, Class I-B-2 Principal Balance, Class I-B-3
Principal Balance, Class I-B-4 Principal Balance, Class I-B-5 Principal Balance
and Class I-B-6 Principal Balance.

      Group II-A Certificate: Any one of the Class II-A-1 Certificates, Class
II-A-2 Certificates, Class II-A-3 Certificates or Class II-A-PO Certificates.

      Group II-A Distribution Amount: As to any Distribution Date and any Class
of Group II-A Certificates (other than the Class II-A-PO Certificates), the
amount distributable to such Class of Group II-A Certificates pursuant to
Paragraphs first clause (B), second clause (B) and third clause (B)(1) of
Section 4.01(a)(i). As to any Distribution Date and the Class II-A-PO
Certificates, the amount distributable to the Class II-A-PO Certificates
pursuant to Paragraphs third clause (B)(2) and fourth clause (B) of Section
4.01(a)(i) on such Distribution Date.

      Group II-A Interest Accrual Amount: As to any Distribution Date, the sum
of the Interest Accrual Amounts for the Group II-A Certificates with respect to
such Distribution Date.

      Group II-A Interest Percentage: As to any Distribution Date and any Class
of Group II-A Certificates, the percentage calculated by dividing the Interest
Accrual Amount of such Class (determined without regard to clause (ii) of the
definition thereof) by the Group II-A Interest Accrual Amount (determined
without regard to clause (ii) of the definition of each Interest Accrual
Amount).

      Group II-A Interest Shortfall Amount: As to any Distribution Date and any
Class of Group II-A Certificates, any amount by which the Interest Accrual
Amount of such Class with respect to such Distribution Date exceeds the amount
distributed in respect of such Class on such Distribution Date pursuant to
Paragraph first clause (B) of Section 4.01(a)(i).

      Group II-A Interest Shortfall Percentage: As to any Distribution Date and
any Class of Group II-A Certificates, the percentage calculated by dividing the
Class A Unpaid Interest Shortfall for such Class by the Aggregate Group II-A
Unpaid Interest Shortfall, in each case determined as of the day preceding the
applicable Distribution Date.

      Group II-A Loss Denominator: As to any Determination Date, an amount equal
to the Group II-A Non-PO Principal Balance.

      Group II-A Loss Percentage: As to any Determination Date and any Class of
Group II-A Certificates, the percentage calculated by dividing the Principal
Balance of such Class by the Group II-A Loss Denominator (determined without
regard to any such Principal Balance of any Class of Group II-A Certificates not
then outstanding), in each case determined as of the preceding Determination
Date.

      Group II-A Non-PO Optimal Amount: As to any Distribution Date, the sum for
such Distribution Date of (i) the Group II-A Interest Accrual Amount, (ii) the
Aggregate Group II-A Unpaid Interest Shortfall and (iii) the Group II-A Non-PO
Optimal Principal Amount.

      Group II-A Non-PO Optimal Principal Amount: As to any Distribution Date,
an amount equal to the sum of (I) the sum, as to each Group II Mortgage Loan
that is an Outstanding Mortgage Loan, of the product of (x) the Non-PO Fraction
with respect to such Mortgage Loan, and (y) the sum of:

            (i) the Group II-A Percentage of the principal portion of the
      Monthly Payment due on the Due Date occurring in the month of such
      Distribution Date on such Mortgage Loan;

            (ii) the Group II-A Prepayment Percentage of all Unscheduled
      Principal Receipts (other than Recoveries) that were received by a
      Servicer with respect to such Mortgage Loan during the Applicable
      Unscheduled Principal Receipt Period relating to such Distribution Date
      for each applicable type of Unscheduled Principal Receipt;

            (iii) the Group II-A Prepayment Percentage of the Scheduled
      Principal Balance of such Mortgage Loan which, during the one month period
      ending on the day preceding the Determination Date for such Distribution
      Date, was repurchased by the Depositor pursuant to Section 2.02, 2.03 or
      3.08; and

            (iv) the Group II-A Percentage of the Substitution Principal Amount
      with respect to each Mortgage Loan for which a Mortgage Loan was
      substituted during the one month period ending on the day preceding the
      Determination Date for such Distribution Date, less the amount allocable
      to the principal portion of any unreimbursed Periodic Advances previously
      made by the applicable Servicer, the Master Servicer or the Trustee in
      respect of such Mortgage Loan for which a Mortgage Loan was substituted;
      and

      (II) the Group II-A Prepayment Percentage of the Non-PO Recovery for Loan
      Group II for such Distribution Date.

      Group II-A Non-PO Principal Balance: As of any date, an amount equal to
the Group II-A Principal Balance less the Principal Balance of the Class II-A-PO
Certificates.

      Group II-A Non-PO Principal Distribution Amount: As to any Distribution
Date, the aggregate amount distributed in respect of the Classes of Group II-A
Certificates pursuant to Paragraph third clause (B)(1) of Section 4.01(a)(i).

      Group II-A Percentage: As to any Distribution Date occurring on or prior
to the applicable Subordination Depletion Date, the lesser of (i) 100% and (ii)
the percentage obtained by dividing the Group II-A Non-PO Principal Balance
(determined as of the Determination Date preceding such Distribution Date) by
the Group II Pool Balance (Non-PO Portion). As to any Distribution Date
occurring subsequent to the applicable Subordination Depletion Date, 100% or
such lesser percentage which will cause the Group II-A Non-PO Principal Balance
to decline to zero following the distribution made on such Distribution Date.

      Group II-A Prepayment Percentage: As to any Distribution Date to and
including the Distribution Date in March 2011, 100%. As to any Distribution Date
subsequent to March 2011 to and including the Distribution Date in March 2012,
the Group II-A Percentage as of such Distribution Date plus 70% of the Group II
Subordinated Percentage as of such Distribution Date. As to any Distribution
Date subsequent to March 2012 to and including the Distribution Date in March
2013, the Group II-A Percentage as of such Distribution Date plus 60% of the
Group II Subordinated Percentage as of such Distribution Date. As to any
Distribution Date subsequent to March 2013 to and including the Distribution
Date in March 2014, the Group II-A Percentage as of such Distribution Date plus
40% of the Group II Subordinated Percentage as of such Distribution Date. As to
any Distribution Date subsequent to March 2014 to and including the Distribution
Date in March 2015, the Group II-A Percentage as of such Distribution Date plus
20% of the Group II Subordinated Percentage as of such Distribution Date. As to
any Distribution Date subsequent to March 2015, the Group II-A Percentage as of
such Distribution Date. The foregoing is subject to the following: (i) if the
aggregate distribution to Holders of Group II-A Certificates on any Distribution
Date of the Group II-A Prepayment Percentage provided above of Unscheduled
Principal Receipts distributable on such Distribution Date would reduce the
Group II-A Non-PO Principal Balance below zero, the Group II-A Prepayment
Percentage for such Distribution Date shall be the percentage necessary to bring
the Group II-A Non-PO Principal Balance to zero and thereafter the Group II-A
Prepayment Percentage shall be zero and (ii) if the Group II-A Percentage as of
any Distribution Date is greater than the Original Group II-A Percentage, the
Group II-A Prepayment Percentage for such Distribution Date shall be 100%.
Notwithstanding the foregoing, with respect to any Distribution Date on which
the following criteria are not met, the reduction of the Group II-A Prepayment
Percentage described in the second through sixth sentences of this definition of
Group II-A Prepayment Percentage shall not be applicable with respect to such
Distribution Date. In such event, the Group II-A Prepayment Percentage for such
Distribution Date will be determined in accordance with the applicable
provision, as set forth in the first through fifth sentences above, which was
actually used to determine the Group II-A Prepayment Percentage for the
Distribution Date occurring in the March preceding such Distribution Date (it
being understood that for the purposes of the determination of the Group II-A
Prepayment Percentage for the current Distribution Date, the current Group II-A
Percentage and Group II Subordinated Percentage shall be utilized).

      No reduction in the Group II-A Prepayment Percentage referred to in the
second through sixth sentences hereof shall be applicable, with respect to any
Distribution Date if (a) the average outstanding principal balance on such
Distribution Date and for the preceding five Distribution Dates on the Group II
Mortgage Loans that were delinquent 60 days or more (including for this purpose
any payments due with respect to Mortgage Loans in foreclosure and REO Mortgage
Loans) were greater than or equal to 50% of the Group II-B Principal Balance or
(b) cumulative Realized Losses on the Group II Mortgage Loans exceed (1) 30% of
the Original Group II Subordinated Principal Balance if such Distribution Date
occurs between and including April 2011 and March 2012, (2) 35% of the Original
Group II Subordinated Principal Balance if such Distribution Date occurs between
and including April 2012 and March 2013, (3) 40% of the Original Group II
Subordinated Principal Balance if such Distribution Date occurs between and
including April 2013 and March 2014, (4) 45% of the Original Group II
Subordinated Principal Balance if such Distribution Date occurs between and
including April 2014 and March 2015, and (5) 50% of the Original Group II
Subordinated Principal Balance if such Distribution Date occurs during or after
April 2015. With respect to any Distribution Date on which the Group II-A
Prepayment Percentage is reduced below the Group II-A Prepayment Percentage for
the prior Distribution Date, the Master Servicer shall certify to the Trustee,
based upon information provided by each Servicer as to the Mortgage Loans
serviced by it that the criteria set forth in the preceding sentence are met.

      Group II-A Principal Balance: As of any date, an amount equal to the sum
of the Principal Balances for the Group II-A Certificates.

      Group II-B Certificate: Any one of the Class II-B-1 Certificates, Class
II-B-2 Certificates, Class II-B-3 Certificates, Class II-B-4 Certificates, Class
II-B-5 Certificates or Class II-B-6 Certificates.

      Group II-B Principal Balance: As of any date, an amount equal to the sum
of the Class II-B-1 Principal Balance, Class II-B-2 Principal Balance, Class
II-B-3 Principal Balance, Class II-B-4 Principal Balance, Class II-B-5 Principal
Balance and Class II-B-6 Principal Balance.

      Holder: See "Certificateholder."

      Independent: When used with respect to any specified Person, such Person
who (i) is in fact independent of the Depositor, the Master Servicer and any
Servicer, (ii) does not have any direct financial interest or any material
indirect financial interest in the Depositor or the Master Servicer or any
Servicer or in an affiliate of either, and (iii) is not connected with the
Depositor, the Master Servicer or any Servicer as an officer, employee,
promoter, underwriter, trustee, partner, director or person performing similar
functions.

      Insurance Policy: Any insurance or performance bond relating to a Mortgage
Loan or the Mortgage Loans, including any hazard insurance, special hazard
insurance, flood insurance, primary mortgage insurance, mortgagor bankruptcy
bond or title insurance.

      Insurance Proceeds: Proceeds paid by any insurer pursuant to any Insurance
Policy covering a Mortgage Loan.

      Insured Expenses: Expenses covered by any Insurance Policy covering a
Mortgage Loan.

      Interest Accrual Amount: As to any Distribution Date and any Class of
Class A Certificates (other than the Class A-PO Certificates), (i) the product
of (a) 1/12th of the Class A Pass-Through Rate for such Class and (b) the
Principal Balance or, in the case of the Class I-A-6 Certificates, the Notional
Amount, of such Class as of the Determination Date immediately preceding such
Distribution Date minus (ii) the sum of (A) the Group I-A Interest Percentage or
Group II-A Interest Percentage, as applicable, of such Class of the interest
portion of any Realized Losses allocated to the Group I-A Certificates or to the
Group II-A Certificates, as applicable, on or after the applicable Subordination
Depletion Date pursuant to Section 4.02(c) and (B) the Group I-A Interest
Percentage or Group II-A Interest Percentage, as applicable, of such Class of
any Non-Supported Interest Shortfall or Relief Act Shortfall allocated to the
Class A Certificates of such Group with respect to such Distribution Date. The
Class A-PO Certificates have no Interest Accrual Amount.

      As to any Distribution Date and any Class of Class B Certificates of a
Group, an amount equal to (i) the product of 1/12th of the Class B Pass-Through
Rate and the Principal Balance of such Class as of the Determination Date
preceding such Distribution Date minus (ii) the Class B Interest Percentage of
such Class of the sum of any Non-Supported Interest Shortfall and any Relief Act
Shortfall allocated to the Class B Certificates of such Group with respect to
such Distribution Date.

      Letter of Credit: As defined in the Wells Fargo Bank Servicing Agreement.

      LIBOR: As to any Distribution Date, the arithmetic mean of the London
Interbank offered rate quotations for one month U.S. dollar deposits, as
determined by the Paying Agent on the related Rate Determination Date in
accordance with Section 4.07.

      LIBOR Business Day: Any Business Day on which banks are open for dealing
in foreign currency and exchange in London, England and the City of New York.

      LIBOR Certificates: Either of the Class I-A-5 or Class I-A-6 Certificates.

      Liquidated Loan: A Mortgage Loan with respect to which the related
Mortgaged Property has been acquired, liquidated or foreclosed and with respect
to which the applicable Servicer determines that all Liquidation Proceeds which
it expects to recover have been recovered.

      Liquidated Loan Loss: With respect to any Distribution Date, the aggregate
of the amount of losses with respect to each Mortgage Loan which became a
Liquidated Loan during the Applicable Unscheduled Principal Receipt Period with
respect to Full Unscheduled Principal Receipts for such Distribution Date, equal
to the excess of (i) the unpaid principal balance of each such Liquidated Loan,
plus accrued interest thereon in accordance with the amortization schedule at
the time applicable thereto at the applicable Net Mortgage Interest Rate from
the Due Date as to which interest was last paid with respect thereto through the
last day of the month preceding the month in which such Distribution Date
occurs, over (ii) Net Liquidation Proceeds with respect to such Liquidated Loan.

      Liquidation Expenses: Expenses incurred by a Servicer in connection with
the liquidation of any defaulted Mortgage Loan or property acquired in respect
thereof (including, without limitation, legal fees and expenses, committee or
referee fees, and, if applicable, brokerage commissions and conveyance taxes),
any unreimbursed advances (including Periodic Advances) expended by such
Servicer pursuant to its Servicing Agreement or the Master Servicer or Trustee
pursuant hereto respecting the related Mortgage Loan, including any unreimbursed
advances for real property taxes or for property restoration or preservation of
the related Mortgaged Property. Liquidation Expenses shall not include any
previously incurred expenses in respect of an REO Mortgage Loan which have been
netted against related REO Proceeds.

      Liquidation Proceeds: Amounts received by a Servicer (including Insurance
Proceeds) or PMI Advances made by a Servicer in connection with the liquidation
of defaulted Mortgage Loans or property acquired in respect thereof, whether
through foreclosure, sale or otherwise, including payments in connection with
such Mortgage Loans received from the Mortgagor, other than amounts required to
be paid to the Mortgagor pursuant to the terms of the applicable Mortgage or to
be applied otherwise pursuant to law.

      Liquidation Profits: As to any Distribution Date and any Mortgage Loan
that became a Liquidated Loan during the Applicable Unscheduled Principal
Receipt Period with respect to Full Unscheduled Principal Receipts for such
Distribution Date, the excess, if any, of (i) Net Liquidation Proceeds in
respect of such Liquidated Loan over (ii) the unpaid principal balance of such
Liquidated Loan plus accrued interest thereon in accordance with the
amortization schedule at the time applicable thereto at the applicable Net
Mortgage Interest Rate from the Due Date to which interest was last paid with
respect thereto through the last day of the month preceding the month in which
such Distribution Date occurs.

      Loan Group: Either of Loan Group I or Loan Group II.

      Loan Group I: The Group I Mortgage Loans.

      Loan Group II: The Group II Mortgage Loans.

      Loan-to-Value Ratio: The ratio, expressed as a percentage, the numerator
of which is the principal balance of a particular Mortgage Loan at origination
and the denominator of which is the lesser of (x) the appraised value of the
related Mortgaged Property determined in the appraisal used by the originator at
the time of origination of such Mortgage Loan, and (y) if the Mortgage is
originated in connection with a sale of the Mortgaged Property, the sale price
for such Mortgaged Property.

      Lower-Tier Distribution Amount: As defined in Section 4.01(a)(iii).

      Lower-Tier REMIC: One of two separate REMICs comprising the Trust Estate,
the assets of which consist of the Mortgage Loans, such amounts as shall from
time to time be held in the Certificate Account, the insurance policies, if any,
relating to a Mortgage Loan and property which secured a Mortgage Loan and which
has been acquired by foreclosure or deed in lieu of foreclosure.

      Master Servicer: Wells Fargo Bank, or its successor in interest.
Initially, the Master Servicer functions shall be performed by the Corporate
Trust Services division of Wells Fargo Bank.

      Master Servicer Errors and Omissions Policy: An insurance policy covering
losses caused by errors or omissions of the Master Servicer and its personnel.

      Master Servicing Fee: With respect to any Mortgage Loan and any
Distribution Date, the fee payable monthly to the Master Servicer pursuant to
Section 6.05 equal to a fixed percentage (expressed as a per annum rate) of the
unpaid principal balance of such Mortgage Loan.

      Master Servicing Fee Rate: As set forth in Section 11.28.

      Master Servicing Officer: Any officer of the Master Servicer involved in,
or responsible for, the administration and master servicing of the Mortgage
Loans.

      MERS: The Mortgage Electronic Registration Systems, Inc.

      MERS Mortgage Loan: Any MOM Mortgage Loan or any other Mortgage Loan as to
which MERS is (or is intended to be) the mortgagee of record and as to which a
MIN has been assigned.

      Mid-Month Receipt Period: With respect to each Distribution Date, the one
month period beginning on the Determination Date (or, in the case of the first
Distribution Date, from and including the Cut-Off Date) occurring in the
calendar month preceding the month in which such Distribution Date occurs and
ending on the day preceding the Determination Date immediately preceding such
Distribution Date.

      MIN: A MERS Mortgage Identification Number assigned to a Mortgage Loan
registered under MERS.

      MOM: A Mortgage Loan where the related Mortgage names MERS as the original
mortgagee thereof, as to which a MIN has been assigned, and which Mortgage has
not been assigned to any other person.

      Month End Interest: As defined in each Servicing Agreement.

      Monthly Payment: As to any Mortgage Loan (including any REO Mortgage Loan)
and any Due Date, the payment of principal and interest due thereon in
accordance with the amortization schedule at the time applicable thereto (after
adjustment for any Curtailments and Deficient Valuations occurring prior to such
Due Date but before any adjustment to such amortization schedule, other than for
Deficient Valuations, by reason of any bankruptcy or similar proceeding or any
moratorium or similar waiver or grace period).

      Moody's: Moody's Investors Service, Inc. or its successor in interest.

      Mortgage: The mortgage, deed of trust or other instrument creating a first
lien on Mortgaged Property securing a Mortgage Note together with any Mortgage
Loan Rider, if applicable.

      Mortgage Interest Rate: As to any Mortgage Loan, the per annum rate at
which interest accrues on the unpaid principal balance thereof as set forth in
the related Mortgage Note, which rate is as indicated on the Mortgage Loan
Schedule.

      Mortgage Loan Purchase Agreement: The mortgage loan purchase agreement
dated as of March 30, 2006 between Wells Fargo Bank, as seller, and the
Depositor, as purchaser.

      Mortgage Loan Rider: The standard Fannie Mae/Freddie Mac riders to the
Mortgage Note and/or Mortgage riders required when the Mortgaged Property is a
condominium unit or a unit in a planned unit development.

      Mortgage Loan Schedule: The list delivered by the Depositor to the
Trustee, the Master Servicer and the Custodian of the Mortgage Loans transferred
to the Trustee on the Closing Date as part of the Trust Estate, which list may
be amended following the Closing Date upon conveyance of a Substitute Mortgage
Loan pursuant to Section 2.02 or 2.03 and which list shall set forth at a
minimum the following information as of the close of business on the Cut-Off
Date (or, with respect to Substitute Mortgage Loans, as of the close of business
on the day of substitution) as to each Mortgage Loan:

            (i) the Mortgage Loan identifying number;

            (ii) the city, state and zip code of the Mortgaged Property;

            (iii) the type of property;

            (iv) the Mortgage Interest Rate;

            (v) the Net Mortgage Interest Rate;

            (vi) the Monthly Payment;

            (vii) the original number of months to maturity;

            (viii) the scheduled maturity date;

            (ix) the Cut-Off Date Principal Balance;

            (x) the Loan-to-Value Ratio at origination;

            (xi) whether such Mortgage Loan is a Subsidy Loan;

            (xii) whether such Mortgage Loan is covered by primary mortgage
      insurance;

            (xiii) the applicable Servicing Fee Rate;

            (xiv) the Master Servicing Fee Rate;

            (xv) Fixed Retained Yield Rate, if applicable;

            (xvi) in the case of any Mortgage Loan initially serviced by Wells
      Fargo Bank, whether such Mortgage Loan is a Type 1 Mortgage Loan or a Type
      2 Mortgage Loan;

            (xvii) the name of the Servicer; and

            (xviii) whether such Mortgage Loan is a Group I Mortgage Loan or a
      Group II Mortgage Loan.

      Such schedule may consist of multiple reports that collectively set forth
all of the information required.

      Mortgage Loans: Each of the mortgage loans transferred and assigned to the
Trustee on the Closing Date pursuant to Section 2.01(a) and any mortgage loans
substituted therefor pursuant to Section 2.02 or 2.03, in each case as from time
to time are included in the Trust Estate as identified in the Mortgage Loan
Schedule.

      Mortgage Note: The note or other evidence of indebtedness evidencing the
indebtedness of a Mortgagor under a Mortgage Loan together with any related
Mortgage Loan Riders, if applicable.

      Mortgaged Property: The property subject to a Mortgage, which may include
Co-op Shares or residential long-term leases.

      Mortgagor: The obligor on a Mortgage Note.

      Net Liquidation Proceeds: As to any defaulted Mortgage Loan, Liquidation
Proceeds net of Liquidation Expenses.

      Net Mortgage Interest Rate: With respect to each Mortgage Loan, a rate
equal to (i) the Mortgage Interest Rate on such Mortgage Loan minus (ii) the sum
of (a) the applicable Servicing Fee Rate, as set forth in Section 11.27 with
respect to such Mortgage Loan, (b) the Master Servicing Fee Rate, as set forth
in Section 11.28 with respect to such Mortgage Loan and (c) the Fixed Retained
Yield Rate, if any, with respect to such Mortgage Loan. Any regular monthly
computation of interest at such rate shall be based upon annual interest at such
rate on the applicable amount divided by twelve.

      Net REO Proceeds: As to any REO Mortgage Loan, REO Proceeds net of any
related expenses of the Servicer.

      Non-permitted Foreign Holder: As defined in Section 5.02(d).

      Non-PO Fraction: With respect to any Group I or Group II Mortgage Loan,
the lesser of (i) 1.00 and (ii) the quotient obtained by dividing the Net
Mortgage Interest Rate for such Mortgage Loan by 5.750%.

      Non-PO Recovery: As to any Distribution Date and each Loan Group, the
amount of all Recoveries for Group I Mortgage Loans or Group II Mortgage Loans,
as applicable, received during the Applicable Unscheduled Principal Receipt
Periods for such Distribution Date less the Class I-A-PO Recovery and Class
II-A-PO Recovery, as applicable, for such Distribution Date.

      Nonrecoverable Advance: Any portion of a Periodic Advance previously made
or proposed to be made in respect of a Mortgage Loan which has not been
previously reimbursed to the Servicer, the Master Servicer or the Trustee, as
the case may be, and which the Servicer, the Master Servicer or the Trustee
determines will not, or in the case of a proposed Periodic Advance would not, be
ultimately recoverable from Liquidation Proceeds or other recoveries in respect
of the related Mortgage Loan. The determination by the Servicer, the Master
Servicer or the Trustee (i) that it has made a Nonrecoverable Advance or (ii)
that any proposed Periodic Advance, if made, would constitute a Nonrecoverable
Advance, shall be evidenced by an Officer's Certificate of the Servicer
delivered to the Master Servicer for redelivery to the Trustee or, in the case
of a Master Servicer determination, an Officer's Certificate of the Master
Servicer delivered to the Trustee, in each case detailing the reasons for such
determination.

      Non-Supported Interest Shortfall: For a Loan Group, with respect to any
Distribution Date, the sum of (i) the excess, if any, of the aggregate
Prepayment Interest Shortfall on the Mortgage Loans of such Loan Group over the
aggregate Compensating Interest with respect to the related Group for such
Distribution Date and (ii) Curtailment Interest Shortfalls with respect to such
Distribution Date. With respect to each Distribution Date occurring on or after
the applicable Subordination Depletion Date, the Non-Supported Interest
Shortfall for a Loan Group determined pursuant to the preceding sentence will be
increased by the amount of any applicable Subordination Depletion Date Interest
Shortfall for the related Group for such Distribution Date. Any Non-Supported
Interest Shortfall for a Loan Group will be allocated to (a) the Group I-A
Certificates and Group II-A Certificates according to the percentage obtained by
dividing the Group I-A Non-PO Principal Balance or Group II-A Non-PO Principal
Balance, as applicable, by the Group I Aggregate Non-PO Principal Balance or
Group II Aggregate Non-PO Principal Balance, as applicable, and (b) the Group
I-B Certificates and Group II-B Certificates according to the percentage
obtained by dividing the Group I-B Principal Balance or Group II-B Principal
Balance, as applicable, by the Group I Aggregate Non-PO Principal Balance or
Group II Aggregate Non-PO Principal Balance, as applicable.

      Non-U.S. Person: As defined in Section 4.01(g).

      Notional Amount: The Class I-A-6 Notional Amount.

      NYCEMA: A New York Consolidation, Extension and Modification Agreement.

      Officer's Certificate: With respect to any Person, a certificate signed by
the Chairman of the Board, the President or a Vice President, and by the
Treasurer, the Secretary or one of the Assistant Treasurers, Assistant
Secretaries or any other duly authorized officer of such Person (or, in the case
of a Person which is not a corporation, signed by the person or persons having
like responsibilities).

      Opinion of Counsel: A written opinion of counsel, who may be outside or
salaried counsel for the Depositor, a Servicer or the Master Servicer, or any
affiliate of the Depositor, a Servicer or the Master Servicer, acceptable to the
Trustee if such opinion is to be delivered to the Trustee; provided, however,
that with respect to REMIC matters, matters relating to the determination of
Eligible Accounts or matters relating to transfers of Certificates, such counsel
shall be Independent.

      Optimal Adjustment Event: With respect to any Class of Class B
Certificates of a Group and any Distribution Date, an Optimal Adjustment Event
will occur with respect to such Class if: (i) the Principal Balance of such
Class on the Determination Date succeeding such Distribution Date would have
been reduced to zero (regardless of whether such Principal Balance was reduced
to zero as a result of principal distribution or the allocation of Realized
Losses) and (ii) (a) the Principal Balance of any Class of Class A Certificates
of the related Group (other than the Class A-PO Certificates) would be subject
to further reduction as a result of the third sentence of the definition of
Principal Balance or (b) the Principal Balance of a Class of Class B
Certificates of such Group with a lower numerical designation would be reduced
with respect to such Distribution Date as a result of the application of the
proviso in the definition of Class I-B-1 Principal Balance, Class I-B-2
Principal Balance, Class I-B-3 Principal Balance, Class I-B-4 Principal Balance,
Class I-B-5 Principal Balance Class I-B-6 Principal Balance, Class II-B-1
Principal Balance, Class II-B-2 Principal Balance, Class II-B-3 Principal
Balance, Class II-B-4 Principal Balance, Class II-B-5 Principal Balance or Class
II-B-6 Principal Balance.

      Original Class I-A-6 Notional Amount: The Original Class I-A-6 Notional
Amount as set forth in Section 11.06(a).

      Original Class I-B-1 Fractional Interest: As to the first Distribution
Date, the percentage obtained by dividing the sum of the Original Class I-B-2
Principal Balance, the Original Class I-B-3 Principal Balance, the Original
Class I-B-4 Principal Balance, the Original Class I-B-5 Principal Balance and
the Original Class I-B-6 Principal Balance by the Original Aggregate Non-PO
Principal Balance for Group I. The Original Class I-B-1 Fractional Interest is
specified in Section 11.12(a).

      Original Class I-B-2 Fractional Interest: As to the first Distribution
Date, the percentage obtained by dividing the sum of the Original Class I-B-3
Principal Balance, the Original Class I-B-4 Principal Balance, the Original
Class I-B-5 Principal Balance and the Original Class I-B-6 Principal Balance by
the Original Aggregate Non-PO Principal Balance for Group I. The Original Class
I-B-2 Fractional Interest is specified in Section 11.13(a).

      Original Class I-B-3 Fractional Interest: As to the first Distribution
Date, the percentage obtained by dividing the sum of the Original Class I-B-4
Principal Balance, the Original Class I-B-5 Principal Balance and the Original
Class I-B-6 Principal Balance by the Original Aggregate Non-PO Principal Balance
for Group I. The Original Class I-B-3 Fractional Interest is specified in
Section 11.14(a).

      Original Class I-B-4 Fractional Interest: As to the first Distribution
Date, the percentage obtained by dividing the sum of the Original Class I-B-5
Principal Balance and the Original Class I-B-6 Principal Balance by the Original
Aggregate Non-PO Principal Balance for Group I. The Original Class I-B-4
Fractional Interest is specified in Section 11.15(a).

      Original Class I-B-5 Fractional Interest: As to the first Distribution
Date, the percentage obtained by dividing the Original Class I-B-6 Principal
Balance by the Original Aggregate Non-PO Principal Balance for Group I. The
Original Class I-B-5 Fractional Interest is specified in Section 11.16(a).

      Original Class I-B-1 Principal Balance: The Class I-B-1 Principal Balance
as of the Cut-Off Date, as set forth in Section 11.11.

      Original Class I-B-2 Principal Balance: The Class I-B-2 Principal Balance
as of the Cut-Off Date, as set forth in Section 11.11.

      Original Class I-B-3 Principal Balance: The Class I-B-3 Principal Balance
as of the Cut-Off Date, as set forth in Section 11.11.

      Original Class I-B-4 Principal Balance: The Class I-B-4 Principal Balance
as of the Cut-Off Date, as set forth in Section 11.11.

      Original Class I-B-5 Principal Balance: The Class I-B-5 Principal Balance
as of the Cut-Off Date, as set forth in Section 11.11.

      Original Class I-B-6 Principal Balance: The Class I-B-6 Principal Balance
as of the Cut-Off Date, as set forth in Section 11.11.

      Original Class II-B-1 Fractional Interest: As to the first Distribution
Date, the percentage obtained by dividing the sum of the Original Class II-B-2
Principal Balance, the Original Class II-B-3 Principal Balance, the Original
Class II-B-4 Principal Balance, the Original Class II-B-5 Principal Balance and
the Original Class II-B-6 Principal Balance by the Original Aggregate Non-PO
Principal Balance for Group II. The Original Class II-B-1 Fractional Interest is
specified in Section 11.12(b).

      Original Class II-B-2 Fractional Interest: As to the first Distribution
Date, the percentage obtained by dividing the sum of the Original Class II-B-3
Principal Balance, the Original Class II-B-4 Principal Balance, the Original
Class II-B-5 Principal Balance and the Original Class II-B-6 Principal Balance
by the Original Aggregate Non-PO Principal Balance for Group II. The Original
Class II-B-2 Fractional Interest is specified in Section 11.13(b).

      Original Class II-B-3 Fractional Interest: As to the first Distribution
Date, the percentage obtained by dividing the sum of the Original Class II-B-4
Principal Balance, the Original Class II-B-5 Principal Balance and the Original
Class II-B-6 Principal Balance by the Original Aggregate Non-PO Principal
Balance for Group II. The Original Class II-B-3 Fractional Interest is specified
in Section 11.14(b).

      Original Class II-B-4 Fractional Interest: As to the first Distribution
Date, the percentage obtained by dividing the sum of the Original Class II-B-5
Principal Balance and the Original Class II-B-6 Principal Balance by the
Original Aggregate Non-PO Principal Balance for Group II. The Original Class
II-B-4 Fractional Interest is specified in Section 11.15(b).

      Original Class II-B-5 Fractional Interest: As to the first Distribution
Date, the percentage obtained by dividing the Original Class II-B-6 Principal
Balance by the Original Aggregate Non-PO Principal Balance for Group II. The
Original Class II-B-5 Fractional Interest is specified in Section 11.16(b).

      Original Class II-B-1 Principal Balance: The Class II-B-1 Principal
Balance as of the Cut-Off Date, as set forth in Section 11.11.

      Original Class II-B-2 Principal Balance: The Class II-B-2 Principal
Balance as of the Cut-Off Date, as set forth in Section 11.11.

      Original Class II-B-3 Principal Balance: The Class II-B-3 Principal
Balance as of the Cut-Off Date, as set forth in Section 11.11.

      Original Class II-B-4 Principal Balance: The Class II-B-4 Principal
Balance as of the Cut-Off Date, as set forth in Section 11.11.

      Original Class II-B-5 Principal Balance: The Class II-B-5 Principal
Balance as of the Cut-Off Date, as set forth in Section 11.11.

      Original Class II-B-6 Principal Balance: The Class II-B-6 Principal
Balance as of the Cut-Off Date, as set forth in Section 11.11.

      Original Group I Class I-B-1 Percentage: The Original Group I Class I-B-1
Percentage as set forth in Section 11.17(a).

      Original Group I Class I-B-2 Percentage: The Original Group I Class I-B-2
Percentage as set forth in Section 11.18(a).

      Original Group I Class I-B-3 Percentage: The Original Group I Class I-B-3
Percentage as set forth in Section 11.19(a).

      Original Group I Class I-B-4 Percentage: The Original Group I Class I-B-4
Percentage as set forth in Section 11.20(a).

      Original Group I Class I-B-5 Percentage: The Original Group I Class I-B-5
Percentage as set forth in Section 11.21(a).

      Original Group I Class I-B-6 Percentage: The Original Group I Class I-B-6
Percentage as set forth in Section 11.22(a).

      Original Group I Subordinated Principal Balance: The aggregate of the
Principal Balances of the Group I-B Certificates as of the Cut-Off Date, as set
forth in Section 11.09.

      Original Group I-A Non-PO Principal Balance: The Original Group I-A Non-PO
Principal Balance as set forth in Section 11.07(a).

      Original Group I-A Percentage: The Group I-A Percentage as of the Cut-Off
Date, as set forth in Section 11.03.

      Original Group II Class II-B-1 Percentage: The Original Group II Class
II-B-1 Percentage as set forth in Section 11.17(b).

      Original Group II Class II-B-2 Percentage: The Original Group II Class
II-B-2 Percentage as set forth in Section 11.18(b).

      Original Group II Class II-B-3 Percentage: The Original Group II Class
II-B-3 Percentage as set forth in Section 11.19(b).

      Original Group II Class II-B-4 Percentage: The Original Group II Class
II-B-4 Percentage as set forth in Section 11.20(b).

      Original Group II Class II-B-5 Percentage: The Original Group II Class
II-B-5 Percentage as set forth in Section 11.21(b).

      Original Group II Class II-B-6 Percentage: The Original Group II Class
II-B-6 Percentage as set forth in Section 11.22(b).

      Original Group II Subordinated Principal Balance: The aggregate of the
Principal Balances of the Group II-B Certificates as of the Cut-Off Date, as set
forth in Section 11.10.

      Original Group II-A Non-PO Principal Balance: The Original Group II-A
Non-PO Principal Balance as set forth in Section 11.07(b).

      Original Group II-A Percentage: The Group II-A Percentage as of the
Cut-Off Date, as set forth in Section 11.04.

      Original Notional Amount: The Original Class I-A-6 Notional Amount set
forth in Section 11.06(a).

      Original Principal Balance: Any of the Original Principal Balances of the
Classes of Class A Certificates as set forth in Section 11.05; the Original
Class I-B-1 Principal Balance, Original Class I-B-2 Principal Balance, Original
Class I-B-3 Principal Balance, Original Class I-B-4 Principal Balance, Original
Class I-B-5 Principal Balance, Original Class I-B-6 Principal Balance, Original
Class II-B-1 Principal Balance, Original Class II-B-2 Principal Balance,
Original Class II-B-3 Principal Balance, Original Class II-B-4 Principal
Balance, Original Class II-B-5 Principal Balance or Original Class II-B-6
Principal Balance as set forth in Section 11.11.

      Other Servicer: Any of the Servicers other than Wells Fargo Bank.

      Other Servicer Mortgage Loan: Any of the Mortgage Loans, if any,
identified on the Mortgage Loan Schedule as serviced by an Other Servicer, as
such Mortgage Loan Schedule may be amended from time to time in connection with
a substitution pursuant to Section 2.02 or 2.03, which Mortgage Loan is serviced
under an Other Servicing Agreement.

      Other Servicing Agreements: The Servicing Agreements other than the Wells
Fargo Bank Servicing Agreement.

      Outstanding Mortgage Loan: As to any Due Date, a Mortgage Loan (including
an REO Mortgage Loan) which was not the subject of a Full Unscheduled Principal
Receipt prior to such Due Date and which was not repurchased by the Depositor
prior to such Due Date pursuant to Section 2.02, 2.03 or 3.08.

      Owner Mortgage Loan File: A file maintained by the Custodian for each
Mortgage Loan that contains the documents specified in Section 2.01(a) and any
additional documents required to be added to the Owner Mortgage Loan File
pursuant to this Agreement.

      Partial Liquidation Proceeds: Liquidation Proceeds received by a Servicer
prior to the Unscheduled Principal Receipt Period in which the related Mortgage
Loan became a Liquidated Loan.

      Partial Unscheduled Principal Receipt: An Unscheduled Principal Receipt
which is not a Full Unscheduled Principal Receipt.

      Paying Agent: The Person authorized to make distributions to
Certificateholders with respect to the Certificates and to forward to
Certificateholders the periodic and annual statements required by Section 4.04.
The Paying Agent may be the Trustee. The initial Paying Agent is appointed in
Section 4.03(b).

      Paying Agent Agreement: As defined in Section 4.03(b).

      Payment Account: The account maintained pursuant to Section 4.03(a).

      Percentage Interest: With respect to a Class A Certificate (other than the
Class I-A-6 Certificates) of a Class, the undivided percentage interest obtained
by dividing the original principal balance of such Certificate by the Original
Principal Balance of such Class of Class A Certificates. With respect to the
Class I-A-6 Certificates, the undivided percentage interest obtained by dividing
the original notional amount evidenced by such Certificate by the Original Class
I-A-6 Notional Amount. With respect to a Class B Certificate of a Class, the
undivided percentage interest obtained by dividing the original principal
balance of such Certificate by the Original Principal Balance of such Class of
Class B Certificates.

      Periodic Advance: The aggregate of the advances required to be made by a
Servicer on any Remittance Date pursuant to its Servicing Agreement or by the
Master Servicer or the Trustee hereunder on any Distribution Date, the amount of
any such advances being equal to the total of all Monthly Payments (adjusted, in
each case (i) in respect of interest, to the applicable Mortgage Interest Rate
less the applicable Servicing Fee in the case of Periodic Advances made by a
Servicer and to the applicable Net Mortgage Interest Rate in the case of
Periodic Advances made by the Master Servicer or Trustee and (ii) by the amount
of any related Debt Service Reductions or reductions in the amount of interest
collectable from the Mortgagor pursuant to the Servicemembers Civil Relief Act,
as it may be amended from time to time, or similar legislation or regulations
then in effect) on the Mortgage Loans, that (x) were delinquent as of the close
of business on the related Determination Date, (y) were not the subject of a
previous Periodic Advance by such Servicer or of a Periodic Advance by the
Master Servicer or the Trustee, as the case may be and (z) have not been
determined by the Master Servicer, such Servicer or Trustee to be Nonrecoverable
Advances.

      Person: Any individual, corporation, partnership, joint venture,
association, joint-stock company, trust, unincorporated organization or
government or any agency or political subdivision thereof.

      Plan: As defined in Section 5.02(c).

      Pledge Holder: As defined in the Wells Fargo Bank Servicing Agreement.

      Pledged Asset Mortgage Loans: The Mortgage Loans listed on Exhibit Q for
which Letters of Credit have been issued.

      PMI Advance: As defined in the related Servicing Agreement, if applicable.

      PO Fraction: With respect to any Discount Mortgage Loan, the difference
between 1.0 and the Non-PO Fraction for such Mortgage Loan; with respect to any
other Mortgage Loan, zero.

      PO Recoveries: Either of the Class I-A-PO Recoveries or Class II-A-PO
Recoveries.

      Pool Balance (Non-PO Portion): Either of the Group I Pool Balance (Non-PO
Portion) or Group II Pool Balance (Non-PO Portion).

      Pool Scheduled Principal Balance: Either of the Group I Pool Scheduled
Principal Balance or Group II Pool Scheduled Principal Balance.

      Prepayment In Full: With respect to any Mortgage Loan, a Mortgagor payment
consisting of a Principal Prepayment in the amount of the outstanding principal
balance of such loan and resulting in the full satisfaction of such obligation.

      Prepayment Interest Shortfall: On any Distribution Date, the amount of
interest, if any, that would have accrued on any Mortgage Loan which was the
subject of a Prepayment in Full at the Net Mortgage Interest Rate for such
Mortgage Loan from the date of its Prepayment in Full (but in the case of a
Prepayment in Full where the Applicable Unscheduled Principal Receipt Period is
the Mid-Month Receipt Period, only if the date of the Prepayment in Full is on
or after the Determination Date in the month prior to the month of such
Distribution Date and prior to the first day of the month of such Distribution
Date) through the last day of the month prior to the month of such Distribution
Date.

      Prepayment Shift Percentage: As to any Distribution Date, the percentage
indicated below:

                                                                    Prepayment
                                                                      Shift
  Distribution Date Occurring In                                    Percentage
  ------------------------------                                    ----------

  April 2006 through March 2011..................................        0%
  April 2011 through March 2012..................................       30%
  April 2012 through March 2013..................................       40%
  April 2013 through March 2014..................................       60%
  April 2014 through March 2015..................................       80%
  April 2015 and thereafter......................................      100%

      Principal Adjustment: In the event that the Class I-B-1 Optimal Principal
Amount, Class I-B-2 Optimal Principal Amount, Class I-B-3 Optimal Principal
Amount, Class I-B-4 Optimal Principal Amount, Class I-B-5 Optimal Principal
Amount, Class I-B-6 Optimal Principal Amount, Class II-B-1 Optimal Principal
Amount, Class II-B-2 Optimal Principal Amount, Class II-B-3 Optimal Principal
Amount, Class II-B-4 Optimal Principal Amount, Class II-B-5 Optimal Principal
Amount or Class II-B-6 Optimal Principal Amount is calculated in accordance with
the proviso in such definition with respect to any Distribution Date, the
Principal Adjustment for such Class of Class B Certificates shall equal the
difference between (i) the amount that would have been distributed to such Class
as principal in accordance with Section 4.01(a)(i) for such Distribution Date,
calculated without regard to such proviso and assuming there are no Principal
Adjustments for such Distribution Date and (ii) the Adjusted Principal Balance
for such Class.

      Principal Balance: As of the first Determination Date and as to any Class
of Class A Certificates of a Group (other than the Class I-A-6 Certificates),
the Original Principal Balance of such Class. As of any subsequent Determination
Date prior to the applicable Subordination Depletion Date and as to any Class of
Class A Certificates (other than the Class A-PO Certificates), the Original
Principal Balance of such Class (increased in the case of a Class of Accrual
Certificates by the Accrual Distribution Amounts for such Class with respect to
prior Distribution Dates) less the sum of all amounts previously distributed in
respect of such Class on prior Distribution Dates (i) pursuant to Paragraph
third clauses (A)(1) and (B)(1) of Section 4.01(a)(i), as applicable, (ii)
pursuant to the provisos in Paragraphs first clause (A) and second clause (A) of
Section 4.01(a)(i) and (iii) as a result of a Principal Adjustment. After the
applicable Subordination Depletion Date, each such Principal Balance of a Class
of Class A Certificates (other than the Class A-PO Certificates) of a Group will
also be reduced (if clause (a) is greater than clause (b)) or increased (if
clause (a) is less than clause (b)) on each Determination Date by an amount
equal to the product of the Group I-A Loss Percentage or Group II-A Loss
Percentage, as applicable, of such Class and the difference, if any, between (a)
the Group I Non-PO Principal Balance or Group II Non-PO Principal Balance, as
applicable, as of such Determination Date without regard to this sentence and
(b) the Group I Adjusted Pool Amount (Non-PO Portion) or Group II Adjusted Pool
Amount (Non-PO Portion), as applicable, for the preceding Distribution Date;
provided, however, that the amount of any such reduction for the Class I-A-3
Certificates will be decreased by the Class I-A-4 Loss Allocation Amount, the
amount of any such reduction for the Class I-A-2, Class I-A-5 and Class I-A-12
Certificates will be decreased by the Class I-A-13 Loss Allocation Amount and
the amount of any such reduction for the Class II-A-1 and Class II-A-2
Certificates will be decreased by the Class II-A-3 Loss Allocation Amount. After
the applicable Subordination Depletion Date, the Principal Balance for the Class
I-A-4 Certificates will additionally be reduced by the Class I-A-4 Loss
Allocation Amount, the Principal Balance for the Class I-A-13 Certificates will
additionally be reduced by the Class I-A-13 Loss Allocation Amount and the
Principal Balance for the Class II-A-3 Certificates will additionally be reduced
by the Class II-A-3 Loss Allocation Amount. In addition, any increase allocated
to the Class I-A-3 Certificates pursuant to the third sentence above will
instead increase the Principal Balance of the Class I-A-4 Certificates, any
increase allocated to the Class I-A-2, Class I-A-5 and Class I-A-12 Certificates
pursuant to the third sentence above will instead increase the Principal Balance
of the Class I-A-13 Certificates and any increase allocated to the Class II-A-1
and Class II-A-2 Certificates pursuant to the third sentence above will instead
increase the Principal Balance of the Class II-A-3 Certificates. Notwithstanding
the foregoing, on any Distribution Date in which the Class I-A-3 Loss Amount
exceeds the Principal Balance of the Class I-A-4 Certificates prior to any
reduction for the Class I-A-4 Loss Allocation Amount, such excess will be
allocated in reduction of the Principal Balance of the Class I-A-3 Certificates.
Notwithstanding the foregoing, on any Distribution Date in which the sum of the
Class I-A-2 Loss Amount, Class I-A-5 Loss Amount and Class I-A-12 Loss Amount
exceeds the Principal Balance of the Class I-A-13 Certificates prior to any
reduction for the Class I-A-13 Loss Allocation Amount, such excess will be
distributed, pro rata, based on the Class I-A-2 Loss Amount, Class I-A-5 Loss
Amount and Class I-A-12 Loss Amount, in reduction of the Principal Balances of
the Class I-A-2, Class I-A-5 and Class I-A-12 Certificates. In no case, however,
will the Principal Balance of the Class I-A-13 Certificates be reduced (i) by
more than $1,800,000 as a result of Class I-A-2 Loss Amounts, (ii) by more than
$1,360,000 as a result of Class I-A-5 Loss Amounts or (iii) by more than
$2,200,000 as a result of Class I-A-12 Loss Amounts. Notwithstanding the
foregoing, on any Distribution Date in which the sum of the Class II-A-1 Loss
Amount and Class II-A-2 Loss Amount exceeds the Principal Balance of the Class
II-A-3 Certificates prior to any reduction for the Class II-A-3 Loss Allocation
Amount, such excess will be distributed, pro rata, based on the Class II-A-1
Loss Amount and Class II-A-2 Loss Amount, in reduction of the Principal Balances
of the Class II-A-1 and Class II-A-2 Certificates.

      As of any subsequent Determination Date and as to the Class I-A-PO and
Class II-A-PO Certificates, the Original Principal Balance of such Class less
the sum of all amounts previously distributed in respect of the Class I-A-PO
Certificates on prior Distribution Dates pursuant to Paragraph third clause
(A)(2) of Section 4.01(a)(i), or all amounts previously distributed in respect
of the Class II-A-PO Certificates on prior Distribution Dates pursuant to
Paragraph third clause (B)(2) of Section 4.01(a)(i), as applicable. The
Principal Balance of such Class A-PO Certificate will also be reduced (if clause
(x) is greater than clause (y)) or increased (if clause (x) is less than clause
(y)) on each Determination Date by the difference, if any, between (x) the
Principal Balance of such Class A-PO Certificate as of such Determination Date
without regard to this sentence and (y) the Group I Adjusted Pool Amount (PO
Portion) or Group II Adjusted Pool Amount (PO Portion), as applicable, for the
preceding Distribution Date.

      The Class I-A-6 Certificates are interest only Certificates and have no
Principal Balance.

      As to the Class B Certificates, the Class I-B-1 Principal Balance, Class
I-B-2 Principal Balance, Class I-B-3 Principal Balance, Class I-B-4 Principal
Balance, Class I-B-5 Principal Balance, Class I-B-6 Principal Balance, the Class
II-B-1 Principal Balance, Class II-B-2 Principal Balance, Class II-B-3 Principal
Balance, Class II-B-4 Principal Balance, Class II-B-5 Principal Balance or Class
II-B-6 Principal Balance, respectively.

      Notwithstanding the foregoing, no Principal Balance of a Class will be
increased on any Determination Date such that the Principal Balance of such
Class exceeds its Original Principal Balance (plus any Accrual Distribution
Amounts previously added to the Principal Balance of a Class of Accrual
Certificates) less all amounts previously distributed in respect of such Class
on prior Distribution Dates pursuant to Paragraph third clauses (A)(1) or (B)(1)
of Section 4.01(a)(i), Paragraph third clauses (A)(2) or (B)(2) of Section
4.01(a)(i), or Paragraphs seventh, tenth, thirteenth, sixteenth, nineteenth or
twenty-second of Section 4.01(a)(i).

      Principal Prepayment: Any Mortgagor payment on a Mortgage Loan which is
received in advance of its Due Date and is not accompanied by an amount
representing scheduled interest for any period subsequent to the date of
prepayment.

      Prior Month Receipt Period: With respect to each Distribution Date, the
calendar month preceding the month in which such Distribution Date occurs.

      Priority Amount 1: For any Distribution Date, the sum of (A) the product
of (1) the Scheduled Principal Amount, (2) the Shift Percentage and (3) the
Priority Percentage 1 and (B) the product of (1) the Unscheduled Principal
Amount, (2) the Prepayment Shift Percentage and (3) the Priority Percentage 1.

      Priority Percentage 1: The sum of the Principal Balances of the Class
I-A-12 and Class I-A-13 Certificates divided by the Group I Pool Balance (Non-PO
Portion).

      Priority Amount 2: For any Distribution Date, the lesser of (i) the
product of (A) 95.00% and (B) the amount available to be distributed to the
Group I-A Certificates (other than the Class I-A-PO Certificates) pursuant to
IV. priority third (b) of Section 4.01(b)(i) and (ii) the product of (A) the
amount available to be distributed to the Group I-A Certificates (other than the
Class I-A-PO Certificates) pursuant to IV. priority third (b) of Section
4.01(b)(i), (B) the Prepayment Shift Percentage and (C) the Priority Percentage
2.

      Priority Percentage 2: (A) the sum of (i) the Principal Balance of the
Class I-A-11 Certificates and (ii) $3,167,000 divided by (B) the sum of the
Principal Balances of the Class I-A-5, Class I-A-7, Class I-A-8, Class I-A-9,
Class I-A-10 and Class I-A-11 Certificates.

      Prohibited Transaction Tax: Any tax imposed under Section 860F of the
Code.

      Prospectus: The prospectus dated March 20, 2006 as supplemented by the
prospectus supplement dated March 27, 2006, relating to the Class A, Class
I-B-1, Class I-B-2, Class I-B-3, Class II-B-1, Class II-B-2 and Class II-B-3
Certificates.

      Prudent Servicing Practices: The standard of care set forth in each
Servicing Agreement.

      Rate Determination Date: As to any Distribution Date and any Class of
LIBOR Certificates, the second LIBOR Business Day preceding the 25th day of the
month preceding the month in which such Distribution Date occurs.

      Rating Agency: Any nationally recognized statistical credit rating agency,
or its successor, that rated one or more Classes of the Certificates at the
request of the Depositor at the time of the initial issuance of the
Certificates. The Rating Agencies for the Group I-A Certificates (other than the
Class I-A-R Certificate) are Fitch, Moody's and S&P. The Rating Agencies for the
Class I-A-R Certificate are Fitch and S&P. The Rating Agencies for the Group
II-A Certificates are Fitch and Moody's. The Rating Agency for the Class I-B-1,
Class I-B-2, Class I-B-3, Class I-B-4, Class I-B-5, Class II-B-1, Class II-B-2,
Class II-B-3, Class II-B-4 and Class II-B-5 Certificates is Fitch. If any such
agency or a successor is no longer in existence, "Rating Agency" shall be such
statistical credit rating agency, or other comparable Person, designated by the
Depositor, notice of which designation shall be given to the Trustee and the
Master Servicer. References herein to the highest short-term rating category of
a Rating Agency shall mean F-1+ in the case of Fitch, P-1 in the case of
Moody's, A-1 in the case of S&P, and in the case of any other Rating Agency
shall mean its equivalent of such ratings. References herein to the highest
long-term rating categories of a Rating Agency shall mean AAA in the case of
Fitch and S&P and Aaa in the case of Moody's, and in the case of any other
Rating Agency shall mean its equivalent of such ratings without any plus or
minus.

      Realized Losses: With respect to any Distribution Date, (i) Liquidated
Loan Losses incurred on Liquidated Loans for which the Liquidation Proceeds were
received during the Applicable Unscheduled Principal Receipt Period with respect
to Full Unscheduled Principal Receipts with respect to such Distribution Date
and (ii) Bankruptcy Losses incurred during the period corresponding to the
Applicable Unscheduled Principal Receipt Period with respect to Full Unscheduled
Principal Receipts for such Distribution Date.

      Record Date: For (i) the Class I-A-5 and Class I-A-6 Certificates, the
Business Day preceding the related Distribution Date and (ii) all other
Certificates, the last Business Day of the month preceding the month of the
related Distribution Date.

      Recovery: Any amount received (net of any reimbursable expenses) on a
Mortgage Loan subsequent to such Mortgage Loan being determined to be a
Liquidated Loan.

      Reference Banks: Initially, the Reference Banks shall be Deutsche Bank
International, Bank of America, N.A., Citibank, N.A., and The Fuji Bank,
Limited. If any of these banks are not available, the Paying Agent shall select
from one of the following banks a substitute Reference Bank: Credit Suisse
Securities (USA) LLC, Westdeutsche Landesbank Girozentrale, The J.P. Morgan
Chase Bank or National Westminster Bank Plc. If any of these banks are not
available, the Paying Agent shall in its discretion select another Reference
Bank.

      Regulation AB: Subpart 229.1100 - Asset Backed Securities (Regulation AB),
17 C.F.R. ss.ss.229.1100-229.1123, as such may be amended from time to time, and
subject to such clarification and interpretation as have been publicly provided
by the Commission in the adopting release (Asset-Backed Securities, Securities
Act Release No. 33-8518, 70 Fed. Reg. 1,506, 1,531 (Jan. 7, 2005)) or by the
staff of the Commission, or as may be provided by the Commission or its staff
from time to time.

      Reimbursement Amount: As defined in Section 2.03(c).

      Relevant Servicing Criteria: The Servicing Criteria applicable to the
Master Servicer, the Trustee, the Custodian or the Servicers, as set forth on
Exhibit R attached hereto and the Servicing Criteria applicable to any Special
Servicer as set forth in the applicable Special Servicing Agreement. For
clarification purposes, multiple parties can have responsibility for the same
Relevant Servicing Criteria. With respect to a Servicing Function Participant
engaged by the Master Servicer, the Trustee, the Custodian, the Special Servicer
(if applicable) or a Servicer, the term "Relevant Servicing Criteria" refers to
the portion of the Relevant Servicing Criteria applicable to the party engaging
such Servicing Function Participant insofar as the functions required to be
performed by such party are to be performed by the Servicing Function
Participant.

      Relief Act Shortfall: Any interest shortfalls arising as a result of the
reduction in the amount of monthly interest payments on any Mortgage Loans as a
result of the application of the Servicemembers Civil Relief Act, as it may be
amended from time to time, or comparable state legislation. Any Relief Act
Shortfall will be allocated to (a) the Group I-A Certificates and Group II-A
Certificates according to the percentage obtained by dividing the Group I-A
Non-PO Principal Balance or Group II-A Non-PO Principal Balance, as applicable,
by the Group I Aggregate Non-PO Principal Balance or Group II Aggregate Non-PO
Principal Balance, as applicable, and (b) the Group I-B Certificates and Group
II-B Certificates according to the percentage obtained by dividing the Group I-B
Principal Balance or Group II-B Principal Balance, as applicable, by the Group I
Aggregate Non-PO Principal Balance or Group II Aggregate Non-PO Principal
Balance, as applicable.

      REMIC: A "real estate mortgage investment conduit" as defined in Code
Section 860D. The Reserve Fund and the Yield Maintenance Agreement are not
assets of either REMIC.

      REMIC Provisions: Provisions of the federal income tax law relating to
REMICs, which appear at Sections 860A through 860G of Part IV of Subchapter M of
Chapter 1 of Subtitle A of the Code, and related provisions, and U.S. Department
of the Treasury temporary, proposed or final regulations promulgated thereunder,
as the foregoing are in effect (or with respect to proposed regulations, are
proposed to be in effect) from time to time.

      Remittance Date: As defined in each of the Servicing Agreements.

      REO Mortgage Loan: Any Mortgage Loan which is not a Liquidated Loan and as
to which the indebtedness evidenced by the related Mortgage Note is discharged
and the related Mortgaged Property is held as part of the Trust Estate.

      REO Proceeds: Proceeds received in respect of any REO Mortgage Loan
(including, without limitation, proceeds from the rental of the related
Mortgaged Property).

      Request for Release: A request for release (which may be in electronic
form) in substantially the form attached as Exhibit G hereto.

      Reserve Fund: The trust account created and maintained by the Master
Servicer pursuant to Section 4.08 which shall be entitled the "Reserve Account,
Wells Fargo Bank, N.A., as Master Servicer, in trust for registered Holders of
the Class I-A-5 Certificates of the Wells Fargo Mortgage Backed Securities
2006-4 Trust" and which must be an Eligible Account. Amounts on deposit in the
Reserve Account shall not be invested. The Reserve Account shall not be an asset
of either REMIC formed under this Agreement.

      Responsible Officer: When used with respect to the Trustee, the Master
Servicer, the Custodian, the Paying Agent or the Authenticating Agent, any
officer of the Corporate Trust Department of the Trustee, the Master Servicer,
the Custodian, the Paying Agent or the Authenticating Agent having direct
responsibility for the administration of this Agreement, including any Senior
Vice President, any Vice President, any Assistant Vice President, any Assistant
Secretary, any Trust Officer or Assistant Trust Officer, or any other employee
of the Trustee, the Master Servicer, the Custodian, the Paying Agent or the
Authenticating Agent customarily performing functions similar to those performed
by any of the above-designated officers. When used with respect to a Servicer, a
Servicing Officer.

      Retained Mortgage Loan File: A file maintained by Wells Fargo Bank prior
to any Document Transfer Date for each Mortgage Loan that contains the documents
specified in Section 2.01(b) and any additional documents required to be added
to the Retained Mortgage Loan File pursuant to this Agreement.

      Rule 144A: Rule 144A promulgated under the 1933 Act.

      Sarbanes-Oxley Certification: As defined in Section 3.12(b).

      S&P: Standard & Poor's, a division of The McGraw-Hill Companies, Inc., or
its successor in interest.

      Scheduled Principal Amount: The sum for each outstanding Group I Mortgage
Loan (including each defaulted Group I Mortgage Loan with respect to which the
related Mortgaged Property has been acquired by the Trust Estate) of the product
of (A) the Non-PO Fraction for such Mortgage Loan and (B) the sum of the amounts
described in clauses (I)(y)(i) and (I)(y)(iv) of the definition of Group I-A
Non-PO Optimal Principal Amount, but without such amount being multiplied by the
Group I-A Percentage.

      Scheduled Principal Balance: As to any Mortgage Loan and Distribution
Date, the principal balance of such Mortgage Loan as of the Due Date in the
month preceding the month of such Distribution Date as specified in the
amortization schedule at the time relating thereto (before any adjustment to
such amortization schedule by reason of any bankruptcy (other than Deficient
Valuations) or similar proceeding or any moratorium or similar waiver or grace
period) after giving effect to (A) Unscheduled Principal Receipts received or
applied by the applicable Servicer during the related Unscheduled Principal
Receipt Period for each applicable type of Unscheduled Principal Receipt related
to the Distribution Date occurring in the month preceding such Distribution
Date, (B) Deficient Valuations incurred prior to such Due Date and (C) the
payment of principal due on such Due Date and irrespective of any delinquency in
payment by the related Mortgagor. Accordingly, the Scheduled Principal Balance
of a Mortgage Loan which becomes a Liquidated Loan at any time through the last
day of such related Unscheduled Principal Receipt Period shall be zero.

      Servicer Mortgage Loan File: As defined in each of the Servicing
Agreements.

      Servicers: Wells Fargo Bank, as a Servicer under the related Servicing
Agreement. Initially the servicing functions performed by Wells Fargo Bank shall
be performed by the Wells Fargo Home Mortgage division of Wells Fargo Bank.

      Servicing Agreements: Each of the Servicing Agreements executed with
respect to a portion of the Mortgage Loans by one of the Servicers, which
agreements are attached hereto, collectively, as Exhibit L.

      Servicing Criteria: The "servicing criteria" set forth in Item 1122(d) of
Regulation AB, as such may be amended from time to time.

      Servicing Fee: With respect to any Servicer, as defined in its Servicing
Agreement.

      Servicing Fee Rate: With respect to a Mortgage Loan, as set forth in
Section 11.27.

      Servicing Function Participant: Any Subservicer, Subcontractor or any
other Person, other than the Master Servicer, the Trustee, the Custodian, the
Special Servicer (if applicable) and the Servicers, that is performing
activities addressed by the Servicing Criteria.

      Servicing Officer: Any officer of a Servicer involved in, or responsible
for, the administration and servicing of the Mortgage Loans.

      Shift Percentage: As to any Distribution Date, the percentage indicated
below:


                                                                      Shift
  Distribution Date Occurring In                                   Percentage
  ------------------------------                                   ----------
  April 2006 through March 2011..................................        0%
  April 2011 and thereafter......................................      100%

      Similar Law: As defined in Section 5.02(c).

      Special Servicer: As defined in Section 3.08.

      Special Servicing Agreement: As defined in Section 3.08.

      Single Certificate: A Certificate of any Class that evidences the smallest
permissible Denomination for such Class, as set forth in Section 11.21.

      Startup Day: As defined in Section 2.05.

      Subcontractor: Any vendor, subcontractor or other Person that is not
responsible for the overall servicing of Mortgage Loans but performs one or more
discrete functions identified in Item 1122(d) of Regulation AB with respect to
Mortgage Loans under the direction or authority of any Servicer (or a
Subservicer of any Servicer), the Master Servicer, the Trustee or the Custodian.

      Subordination Depletion Date: With respect to each Group, the Distribution
Date preceding the first Distribution Date on which each of the Group I-A
Percentage and Group II-A Percentage, as applicable, (in each case, determined
pursuant to clause (ii) of the definition thereof) equals or exceeds 100%.

      Subordination Depletion Date Interest Shortfall: With respect to any
Distribution Date that occurs on or after the applicable Subordination Depletion
Date with respect to any Unscheduled Principal Receipt (other than a Prepayment
in Full or Curtailment):

      (A)   in the case where the Applicable Unscheduled Principal Receipt
            Period is the Mid-Month Receipt Period and such Unscheduled
            Principal Receipt is received by the Servicer on or after the
            Determination Date in the month preceding the month of such
            Distribution Date but prior to the first day of the month of such
            Distribution Date, the amount of interest that would have accrued at
            the Net Mortgage Interest Rate on the amount of such Unscheduled
            Principal Receipt from the day of its receipt or, if earlier, its
            application by the Servicer through the last day of the month
            preceding the month of such Distribution Date; and

      (B)   in the case where the Applicable Unscheduled Principal Receipt
            Period is the Prior Month Receipt Period and such Unscheduled
            Principal Receipt is received by the Servicer during the month
            preceding the month of such Distribution Date, the amount of
            interest that would have accrued at the Net Mortgage Interest Rate
            on the amount of such Unscheduled Principal Receipt from the day of
            its receipt or, if earlier, its application by the Servicer through
            the last day of the month in which such Unscheduled Principal
            Receipt is received.

      Subservicer: Any Person that (i) services Mortgage Loans on behalf of any
Servicer, and (ii) is responsible for the performance (whether directly or
through Subservicers or Subcontractors) of a substantial portion of the material
servicing functions required to be performed under this Agreement, any related
Servicing Agreement or any sub-servicing agreement that are identified in Item
1122(d) of Regulation AB.

      Subsidy Account: If the Trust Estate contains any Subsidy Loans, the
deposit account or accounts created and maintained by the Servicer for deposit
of Subsidy Funds and amounts payable under interest subsidy agreements relating
to mortgage loans other than the Mortgage Loans.

      Subsidy Funds: If the Trust Estate contains any Subsidy Loans, funds
contributed by the employer of a Mortgagor in order to reduce the payments
required from the Mortgagor for a specified period in specified amounts.

      Subsidy Loan: Any Mortgage Loan subject to a temporary interest subsidy
agreement pursuant to which the monthly interest payments made by the related
Mortgagor will be less than the scheduled monthly interest payments on such
Mortgage Loan, with the resulting difference in interest payments being provided
by the employer of the Mortgagor.

      Substitute Mortgage Loan: As defined in Section 2.02.

      Substitution Principal Amount: With respect to any Mortgage Loan
substituted in accordance with Section 2.02 or pursuant to Section 2.03, the
excess of (x) the unpaid principal balance of the Mortgage Loan which is
substituted for over (y) the unpaid principal balance of the Substitute Mortgage
Loan, each balance being determined as of the date of substitution.

      TAC Certificates: The Class I-A-5 Certificates.

      TAC Principal Amount: As defined in Section 4.01(b).

      Trust: The New York common law trust created by this Agreement.

      Trust Estate: The corpus of the Trust, consisting of the Mortgage Loans
(other than any Fixed Retained Yield), such amounts as may be held from time to
time in the Certificate Account (other than any Fixed Retained Yield) or the
Reserve Fund, the rights of the Trustee to receive the proceeds of all insurance
policies and performance bonds, if any, required to be maintained hereunder or
under the related Servicing Agreement, property which secured a Mortgage Loan
and which has been acquired by foreclosure or deed in lieu of foreclosure, the
Master Servicer's rights under the Yield Maintenance Agreement and all other
property and rights described in the first paragraph of Section 2.01(a).

      Trustee: U.S. Bank National Association, a national banking association,
or any successor trustee appointed as herein provided.

      Type 1 Mortgage Loan: The Mortgage Loans, if any, identified as such in
the Mortgage Loan Schedule as such Mortgage Loan Schedule may be amended from
time to time in connection with a substitution pursuant to Section 2.02 or 2.03,
serviced under the Wells Fargo Bank Servicing Agreement and having a Mid-Month
Receipt Period with respect to all types of Unscheduled Principal Receipts.

      Type 2 Mortgage Loan: The Mortgage Loans, if any, identified as such in
the Mortgage Loan Schedule as such Mortgage Loan Schedule may be amended from
time to time in connection with a substitution pursuant to Section 2.02 or 2.03,
serviced under the Wells Fargo Bank Servicing Agreement and having a Prior Month
Receipt Period with respect to all types of Unscheduled Principal Receipts.

      Uncertificated Lower-Tier Interest: Any of the Class I-A-L1 Interest, the
Class I-A-L5 Interest, the Class I-A-LPO Interest, the Class I-A-LUR Interest,
the Class II-A-L1 Interest, the Class II-A-L2 Interest, the Class II-A-L3
Interest, the Class II-A-LPO Interest, the Class I-B-L1 Interest, the Class
I-B-L2 Interest, the Class I-B-L3 Interest, the Class I-B-L4 Interest, the Class
I-B-L5 Interest, the Class I-B-L6 Interest, the Class II-B-L1 Interest, the
Class II-B-L2 Interest, the Class II-B-L3 Interest, the Class II-B-L4 Interest,
the Class II-B-L5 Interest and the Class II-B-L6 Interest.

      Unpaid Interest Shortfalls: Each of the Class A Unpaid Interest
Shortfalls, the Class I-B-1 Unpaid Interest Shortfall, the Class I-B-2 Unpaid
Interest Shortfall, the Class I-B-3 Unpaid Interest Shortfall, the Class I-B-4
Unpaid Interest Shortfall, the Class I-B-5 Unpaid Interest Shortfall, the Class
I-B-6 Unpaid Interest Shortfall, Class II-B-1 Unpaid Interest Shortfall, the
Class II-B-2 Unpaid Interest Shortfall, the Class II-B-3 Unpaid Interest
Shortfall, the Class II-B-4 Unpaid Interest Shortfall, the Class II-B-5 Unpaid
Interest Shortfall and the Class II-B-6 Unpaid Interest Shortfall.

      Unscheduled Principal Amount: The sum for each outstanding Group I
Mortgage Loan (including each defaulted Group I Mortgage Loan with respect to
which the related Mortgaged Property has been acquired by the Trust Estate) of
the product of (A) the Non-PO Fraction for such Mortgage Loan and (B) the sum of
the amounts described in clauses (I)(y)(ii) and (I)(y)(iii) of the definition of
Group I-A Non-PO Optimal Principal Amount, but without such amount being
multiplied by the Group I-A Prepayment Percentage.

      Unscheduled Principal Receipt: Any Principal Prepayment or other recovery
of principal on a Mortgage Loan, including, without limitation, the principal
portion of Net Liquidation Proceeds, the principal portion of Net REO Proceeds,
Recoveries and proceeds received from any condemnation award or proceeds in lieu
of condemnation other than that portion of such proceeds released to the
Mortgagor in accordance with the terms of the Mortgage or Prudent Servicing
Practices, but excluding any Liquidation Profits and proceeds of a repurchase of
a Mortgage Loan by the Depositor and any Substitution Principal Amounts.

      Unscheduled Principal Receipt Period: Either a Mid-Month Receipt Period or
a Prior Month Receipt Period.

      Upper-Tier Certificate: Any one of the Class A Certificates (other than
that portion of the Class I-A-R Certificate represented by the Class I-A-LR
Interest) and the Class B Certificates.

      Upper-Tier Certificate Account: The trust account established and
maintained pursuant to Section 4.01(e).

      Upper-Tier REMIC: One of the two separate REMICs comprising the Trust
Estate, the assets of which consist of the Uncertificated Lower-Tier Interests
and such amounts as shall from time to time be held in the Upper-Tier
Certificate Account.

      U.S. Person: As defined in Section 4.01(g).

      Voting Interest: With respect to any provisions hereof providing for the
action, consent or approval of the Holders of all Certificates evidencing
specified Voting Interests in the Trust Estate, the Class I-A-6 Certificates
will be entitled to 1% of the aggregate Voting Interest represented by all
Certificates and the remaining Classes of Certificates will be entitled to a pro
rata portion of the remaining Voting Interest equal to the ratio obtained by
dividing the Principal Balance of such Class by the sum of the Group I-A
Principal Balance, the Group II-A Principal Balance, the Group I-B Principal
Balance and the Group II-B Principal Balance. Each Certificateholder of a Class
will have a Voting Interest equal to the product of the Voting Interest to which
such Class is collectively entitled and the Percentage Interest in such Class
represented by such Holder's Certificates. With respect to any provisions hereof
providing for action, consent or approval of each Class of Certificates or
specified Classes of Certificates, each Certificateholder of a Class will have a
Voting Interest in such Class equal to such Holder's Percentage Interest in such
Class.

      Wells Fargo Bank: Wells Fargo Bank, N.A., or its successor in interest.

      Wells Fargo Bank Correspondents: The entities identified on a list
provided by Wells Fargo Bank to the Master Servicer, from which Wells Fargo Bank
purchased the Mortgage Loans.

      Wells Fargo Bank Servicing Agreement: The Servicing Agreement providing
for the servicing of those Mortgage Loans that are initially serviced by Wells
Fargo Bank.

      Yield Maintenance Agreement: The yield maintenance agreement between the
Master Servicer, on behalf of the Trust, and the Counterparty, which will be
primarily for the benefit of the Class I-A-5 Certificates, substantially in the
form attached hereto as Exhibit W. The Yield Maintenance Agreement shall not be
an asset of either REMIC formed under this Agreement.

      Yield Maintenance Agreement Payment: For any Distribution Date prior to
and including the Distribution Date in December 2021, the amount, if any,
required to be paid by the Counterparty to the Master Servicer under the Yield
Maintenance Agreement.

      Section 1.02 Acts of Holders.

      (a) Any request, demand, authorization, direction, notice, consent, waiver
or other action provided by this Agreement to be given or taken by Holders may
be embodied in and evidenced by one or more instruments of substantially similar
tenor signed by such Holders in person or by an agent duly appointed in writing.
Except as herein otherwise expressly provided, such action shall become
effective when such instrument or instruments are delivered to the Trustee.
Proof of execution of any such instrument or of a writing appointing any such
agent shall be sufficient for any purpose of this Agreement and conclusive in
favor of the Trustee, if made in the manner provided in this Section 1.02. The
Trustee shall promptly notify the Master Servicer in writing of the receipt of
any such instrument or writing.

      (b) The fact and date of the execution by any Person of any such
instrument or writing may be proved by the affidavit of a witness of such
execution or by a certificate of a notary public or other officer authorized by
law to take acknowledgments of deeds, certifying that the individual signing
such instrument or writing acknowledged to him the execution thereof. When such
execution is by a signer acting in a capacity other than his or her individual
capacity, such certificate or affidavit shall also constitute sufficient proof
of his or her authority. The fact and date of the execution of any such
instrument or writing, or the authority of the individual executing the same,
may also be proved in any other manner which the Trustee deems sufficient.

      (c) The ownership of Certificates (whether or not such Certificates shall
be overdue and notwithstanding any notation of ownership or other writing
thereon made by anyone other than the Trustee and the Authenticating Agent)
shall be proved by the Certificate Register, and none of the Trustee, the
Depositor or the Master Servicer shall be affected by any notice to the
contrary.

      (d) Any request, demand, authorization, direction, notice, consent, waiver
or other action of the Holder of any Certificate shall bind every future Holder
of the same Certificate and the Holder of every Certificate issued upon the
registration of transfer thereof or in exchange therefor or in lieu thereof in
respect of anything done, omitted or suffered to be done by the Trustee, the
Depositor or the Master Servicer in reliance thereon, whether or not notation of
such action is made upon such Certificate.

      Section 1.03 Effect of Headings and Table of Contents.

      The Article and Section headings in this Agreement and the Table of
Contents are for convenience of reference only and shall not affect the
interpretation or construction of this Agreement.

      Section 1.04 Benefits of Agreement.

      Nothing in this Agreement or in the Certificates, express or implied,
shall give to any Person, other than the parties to this Agreement and their
successors hereunder and the Holders of the Certificates any benefit or any
legal or equitable right, power, remedy or claim under this Agreement.

                                   ARTICLE II

                          CONVEYANCE OF MORTGAGE LOANS;

                      ORIGINAL ISSUANCE OF THE CERTIFICATES

      Section 2.01 Conveyance of Mortgage Loans.

      (a) The Depositor, concurrently with the execution and delivery hereof,
does hereby assign to the Trustee, without recourse all the right, title and
interest of the Depositor in and to (a) the Trust Estate, including all interest
(other than the portion, if any, representing the Fixed Retained Yield) and
principal received by the Depositor on or with respect to the Mortgage Loans
after the Cut-Off Date (and including scheduled payments of principal and
interest due after the Cut-Off Date but received by the Depositor on or before
the Cut-Off Date and Unscheduled Principal Receipts received or applied on the
Cut-Off Date, but not including payments of principal and interest due on the
Mortgage Loans on or before the Cut-Off Date), (b) the Insurance Policies, (c)
the obligations of the Servicers under the Servicing Agreements with respect to
the Mortgage Loans, (d) the right to receive amounts, if any, payable on behalf
of any Mortgagor from the Subsidy Account relating to any Subsidy Loan, (e) all
of the Depositor's right, title and interest in and to the proceeds of the
Letters of Credit and (f) proceeds of all the foregoing. It is agreed and
understood by the Depositor and the Trustee that it is not intended that any
mortgage loan be included in the Trust Estate that is a "High-Cost Home Loan" as
defined in any of (i) the New Jersey Home Ownership Act effective November 27,
2003, (ii) the New Mexico Home Loan Protection Act effective January 1, 2004,
(iii) the Massachusetts Predatory Home Loan Practices Act effective November 7,
2004 or (iv) the Indiana Home Loan Practices Act, effective January 1, 2005.

      In connection with such assignment, the Depositor shall, with respect to
each Mortgage Loan, deliver, or cause to be delivered, to the Custodian, on or
before the Closing Date the following documents or instruments with respect to
each Mortgage Loan.

            (i) The original Mortgage Note either (A) endorsed in blank or (B)
      endorsed as provided in Section 2.01(d), with all prior and intervening
      endorsements as may be necessary to show a complete chain of endorsements
      or with respect to any Mortgage Loan as to which the original Mortgage
      Note has been permanently lost or destroyed and has not been replaced, a
      lost note affidavit with a copy of the Mortgage Note and, in the case of
      any Mortgage Loan originated in the State of New York documented by a
      NYCEMA, the NYCEMA, the new Mortgage Note, if applicable, the consolidated
      Mortgage Note and the consolidated Mortgage;

            (ii) A recorded original assignment of the related Mortgage from
      Wells Fargo Bank assigning the related Mortgage to the Trustee (which may
      be assigned in blank), certified by the recording office, or, if such
      assignment is in the process of being recorded, a copy of the related
      Mortgage transmitted for recordation certified by an officer of Wells
      Fargo Bank or applicable Wells Fargo Bank Correspondent to be a true and
      correct copy of such assignment submitted for recordation; provided,
      however, if recordation is not required as described below, an assignment
      in recordable form (which may be assigned in blank) with respect to the
      related Mortgage;

            (iii) The original of each assumption agreement, modification,
      written assurance or substitution agreement pertaining to such Mortgage
      Note, if any;

            (iv) For each Mortgage Loan secured by Co-op Shares, the originals
      of the following documents or instruments:

                  (a)   The loan security agreement;

                  (b)   The stock certificate;

                  (c)   The stock power, executed in blank;

                  (d)   The executed proprietary lease;

                  (e)   The executed recognition agreement;

                  (f)   The executed UCC-1 financing statement with evidence of
                        recording thereon; and

                  (g)   The executed UCC-3 financing statements or other
                        appropriate UCC financing statements required by state
                        law, evidencing a complete and unbroken chain from the
                        mortgagee to the Trustee with evidence of recording
                        thereon (or in a form suitable for recordation); and

            (v) For each Letter of Credit, the original advice of such Letter of
      Credit endorsed by the Pledge Holder and Wells Fargo Bank's notice of
      transfer (Exhibit A to the Letter of Credit) of beneficiary of such Letter
      of Credit to the Trustee.

      (b) The Master Servicer shall promptly notify the Depositor, the Trustee
and the Custodian of the occurrence of any Document Transfer Event of which the
Master Servicer had knowledge. Following the receipt of such notice, the
Depositor shall, with respect to each Mortgage Loan, deliver, or cause to be
delivered, to the Custodian, no later than the Document Transfer Date, copies
(which may be in electronic form mutually agreed upon by the Depositor and the
Custodian) of the following additional documents or instruments with respect to
each Mortgage Loan; provided, however, that originals of such documents or
instruments shall be delivered to the Custodian if originals are required under
the law in which the related Mortgaged Property is located in order to exercise
all remedies available to the Trust under applicable law following default by
the related Mortgagor:

            (i) The original recorded Mortgage with evidence of recordation
      noted thereon or attached thereto, together with any addenda or riders
      thereto, or a copy of such recorded Mortgage with such evidence of
      recordation certified to be true and correct by the appropriate
      governmental recording office; or a copy of such recorded Mortgage with
      such evidence of recordation, or if the original Mortgage has been
      submitted for recordation but has not been returned from the applicable
      public recording office, a copy of the Mortgage certified by an officer of
      Wells Fargo Bank or the applicable Wells Fargo Bank Correspondent to be a
      true and correct copy of the original Mortgage submitted for recordation;

            (ii) The original of each assumption agreement, modification,
      written assurance or substitution agreement pertaining to such Mortgage,
      if any, or, if such document is in the process of being recorded, a copy
      of such document, certified by an officer of Wells Fargo Bank or the
      applicable Wells Fargo Bank Correspondent of such Mortgage Loan or by the
      applicable title insurance company, closing agent, settlement agent,
      escrow agent or closing attorney to be a true and correct copy of such
      document transmitted for recordation, if any;

            (iii) For each MERS Mortgage Loan that is not a MOM Mortgage Loan,
      the original assignment showing MERS as the assignee of the Mortgage, with
      evidence of recording thereon or copies thereof certified by an officer of
      Wells Fargo Bank or the applicable Wells Fargo Bank Correspondent to have
      been submitted for recordation;

            (iv) Each original recorded intervening assignment of the Mortgage
      as may be necessary to show a complete chain of title from the Mortgage
      Loan originator to Wells Fargo Bank or Wells Fargo Home Mortgage, Inc.,
      with evidence of recordation noted thereon or attached thereto, or a copy
      of such assignment with such evidence of recordation to be true and
      correct by the appropriate governmental recording office, or, if any such
      assignment has been submitted for recordation but has not been returned
      from the applicable public recording office or is not otherwise available,
      a copy of such assignment certified by an officer of Wells Fargo Bank or
      the applicable Wells Fargo Bank Correspondent to be a true and correct
      copy of the recorded assignment submitted for recordation; and

            (v) The original policy of the title insurance or certificate of
      title insurance or a written commitment to issue such a title insurance
      policy or certificate of title insurance, or a copy of such title
      insurance certified as true and correct by the applicable insurer or any
      attorney's certificate of title with an Officer's Certificate of Wells
      Fargo Bank or the applicable Wells Fargo Bank Correspondent that such
      attorney's certificate of title is customarily used in lieu of a title
      insurance policy in the jurisdiction in which the related mortgage
      property is located.

      (c) If any assignment of a Mortgage to the Trustee is in the process of
being recorded on the Closing Date, the Depositor shall use its best efforts to
cause each such original recorded document or certified copy thereof to be
delivered to the Custodian promptly following its recordation, but in no event
later than one (1) year following the Closing Date. If any Mortgage has been
recorded in the name of MERS or its designee, no assignment of Mortgage in favor
of the Trustee will be required to be prepared or delivered and instead, the
Master Servicer shall enforce any obligation of the Servicers under the
Servicing Agreements to take all actions as are necessary to cause the Trust
Estate to be shown as the owner of the related Mortgage Loan on the records of
MERS for the purpose of the system of recording transfers of beneficial
ownership of mortgages maintained by MERS. The Depositor shall also cause to be
delivered to the Custodian any other original mortgage loan document included in
the Owner Mortgage Loan File if a copy thereof has been delivered. The Depositor
shall pay from its own funds, without any right of reimbursement therefor, the
amount of any costs, liabilities and expenses incurred by the Trust Estate by
reason of the failure of the Depositor to cause to be delivered to the Custodian
within one (1) year following the Closing Date any assignment of a Mortgage
(except with respect to any Mortgage recorded in the name of MERS) not delivered
to the Custodian on the Closing Date.

      In lieu of recording an assignment of any Mortgage the Depositor may,
deliver or cause to be delivered to the Custodian the assignment of the Mortgage
Loan to the Trustee in a form suitable for recordation, if (i) with respect to a
particular state the Trustee has received an Opinion of Counsel acceptable to it
that such recording is not required to make the assignment effective against the
parties to the Mortgage or subsequent purchasers or encumbrances of the
Mortgaged Property or (ii) the Depositor has been advised by each Rating Agency
that non-recordation in a state will not result in a reduction of the rating
assigned by that Rating Agency at the time of initial issuance of the
Certificates. Set forth on Exhibit K attached hereto is a list of all states
where recordation is required by any Rating Agency to obtain the initial ratings
of the Certificates. The Custodian may rely and shall be protected in relying
upon the information contained in such Exhibit K. In the event that the
Custodian receives notice that recording is required to protect the right, title
and interest of the Trustee in and to any such Mortgage Loan for which
recordation of an assignment has not previously been required, the Custodian
shall promptly notify the Trustee and the Custodian shall within five Business
Days (or such other reasonable period of time mutually agreed upon by the
Custodian and the Trustee) of its receipt of such notice deliver each previously
unrecorded assignment to the related Servicer for recordation.

      (d) Except for Mortgage Notes endorsed in blank, endorsements shall comply
with the following format:

                                WITHOUT RECOURSE
                              PAY TO THE ORDER OF:
              U.S. BANK NATIONAL ASSOCIATION, AS TRUSTEE under the
                              pooling and servicing
                          agreement dated as of [date].
                         and its successors and assigns,

          [Wells Fargo Bank, N.A.] or [Wells Fargo Home Mortgage, Inc.]
                             [Signature of Officer]
                           [Officer's Name and Title]

      Except where assignments in blank are authorized or in the case of any
Mortgage registered in the name of MERS, assignments of any Mortgage shall
comply with the following:

                      U.S. BANK NATIONAL ASSOCIATION, AS
                                     TRUSTEE
                         and its successors and assigns

      (e) Concurrently with the execution and delivery of this Agreement, the
Depositor shall deliver the Mortgage Loan Schedule to the Trustee, the Master
Servicer and the Custodian. The Depositor and the Master Servicer shall provide
a copy of the Mortgage Loan Schedule to any Certificateholders upon written
request made to it at the addresses set forth on Exhibit F, as the same may be
amended from time to time by written notice from such party to the other parties
hereto.

      Section 2.02 Acceptance by Custodian.

      Subject to the provisions of the following paragraph, pursuant to the
Custodial Agreement, the Custodian, on behalf of the Trustee, will declare that
it holds and will hold the documents delivered to it pursuant to Section 2.01(a)
above and the other documents constituting a part of the Owner Mortgage Loan
Files or Retained Mortgage Loan Files (after the occurrence of a Document
Transfer Event) delivered to it in trust, upon the trusts herein set forth, for
the use and benefit of all present and future Certificateholders. Upon execution
of this Agreement, the Custodian will deliver to the Depositor and the Trustee
an initial certification in the form of Exhibit N hereto, to the effect that,
except as may be specified in a list of exceptions attached thereto, it has
received the original Mortgage Notes relating to each Mortgage Loan on the
Mortgage Loan Schedule.

      The Custodian will review each Owner Mortgage Loan File within 45 days
after execution of this Agreement. The Custodian will deliver no later than 30
days after completion of such review to the Depositor and the Trustee a final
certification in the form of Exhibit O hereto to the effect that, except as may
be specified in a list of exceptions attached thereto, all required documents
set forth in Section 2.01(a) have been executed and received and appear regular
on their face, and that such documents relate to the Mortgage Loans identified
in the Mortgage Loan Schedule based on a comparison of the Mortgage Loan
identifying number, Mortgagor name and street address, and in so doing the
Custodian may rely on the purported due execution and genuineness of any such
document and on the purported genuineness of any signature thereon.

      If within such 45 day period the Custodian finds any document constituting
a part of an Owner Mortgage Loan File not to have been executed or received or
to be unrelated to the Mortgage Loans identified in the Mortgage Loan Schedule
or not to appear regular on its face, the Custodian shall promptly (and in no
event more than 30 days after completion of the review) notify the Trustee and
the Trustee shall notify the Depositor. The Depositor shall have a period of 60
days after the date of such notice within which to correct or cure any such
defect. The Depositor hereby covenants and agrees that, if any material defect
is not so corrected or cured, the Depositor will, not later than 60 days after
the Trustee's notice to it referred to above respecting such defect, either (i)
repurchase the related Mortgage Loan or any property acquired in respect thereof
from the Trust Estate at a price equal to the Repurchase Price or (ii) if within
two years of the Startup Day, or such other period permitted by the REMIC
Provisions, substitute for any Mortgage Loan to which such material defect
relates, a new mortgage loan (a "Substitute Mortgage Loan") having such
characteristics so that the representations and warranties of the Depositor set
forth in Section 2.03(b) hereof (other than Section 2.03(b)(i)) would not have
been incorrect had such Substitute Mortgage Loan originally been a Mortgage
Loan. In no event shall any Substitute Mortgage Loan have an unpaid principal
balance, as of the date of substitution, greater than the Scheduled Principal
Balance (reduced by the scheduled payment of principal due on the Due Date in
the month of substitution) of the Mortgage Loan for which it is substituted. In
addition, such Substitute Mortgage Loan shall have a Loan-to-Value Ratio less
than or equal to and a Net Mortgage Interest Rate equal to that of the Mortgage
Loan for which it is substituted.

      In the case of a repurchased Mortgage Loan or property, the Repurchase
Price shall be deposited by the Depositor in the Certificate Account maintained
by the Master Servicer pursuant to Section 3.01. In the case of a Substitute
Mortgage Loan, the Owner Mortgage Loan File (and Retained Mortgage Loan File, if
required pursuant to Section 2.01(b) hereof) relating thereto shall be delivered
to the Custodian and the Substitution Principal Amount (if any), together with
(i) interest on such Substitution Principal Amount at the applicable Net
Mortgage Interest Rate to the following Due Date of such Mortgage Loan which is
being substituted for and (ii) an amount equal to the aggregate amount of
unreimbursed Periodic Advances in respect of interest previously made by the
Servicer, the Master Servicer or the Trustee with respect to such Mortgage Loan,
shall be deposited in the Certificate Account. The Monthly Payment on the
Substitute Mortgage Loan for the Due Date in the month of substitution shall not
be part of the Trust Estate. Upon receipt by the Custodian of a Request for
Release signed by an officer of the Depositor, the Custodian shall release to
the Depositor the Owner Mortgage Loan File (and Retained Mortgage Loan File, if
applicable) of the Mortgage Loan being removed. The Trustee shall execute and
deliver such instrument of transfer or assignment (or, in the case of a Mortgage
Loan registered in the name of MERS or its designee, the Master Servicer shall
enforce the obligation of the applicable Servicer under the related Servicing
Agreement to take all necessary action to reflect such assignment on the records
of MERS), in each case without recourse, as shall be necessary to vest in the
Depositor legal and beneficial ownership of such substituted or repurchased
Mortgage Loan or property. It is understood and agreed that the obligation of
the Depositor to substitute a new Mortgage Loan for or repurchase any Mortgage
Loan or property as to which such a material defect in a constituent document
exists shall constitute the sole remedy respecting such defect available to the
Certificateholders or the Trustee on behalf of the Certificateholders. The
failure of the Custodian to give the final certification or the Trustee to give
any notice within the required time periods shall not affect or relieve the
Depositor's obligation to repurchase any Mortgage Loan pursuant to this Section
2.02.

      The Trustee shall be responsible for enforcing the Depositor's obligations
under this Section 2.02. If the Trustee receives written notice from the
Custodian or the Master Servicer that the defect is not cured by the Depositor
within 60 days after the Trustee's notice, the Trustee shall enforce the
Depositor's obligation to repurchase such Mortgage Loan or substitute for such
Mortgage Loan in accordance with the provisions of this Section 2.02. In
connection with any substitution permitted by this Section 2.02, the Master
Servicer shall verify that the unpaid principal balance and the Loan-to-Value
Ratio of the Substitute Mortgage Loan satisfy the requirements of this Section
2.02.

      The Master Servicer is hereby directed to execute and deliver, on behalf
of the Trust, the Yield Maintenance Agreement.

      Section 2.03 Representations and Warranties of the Master Servicer and the
Depositor.

      (a) The Master Servicer hereby represents and warrants to the Trustee for
the benefit of the Certificateholders that, as of the date of execution of this
Agreement:

            (i) The Master Servicer is a national banking association duly
      chartered and validly existing in good standing under the laws of the
      United States;

            (ii) The execution and delivery of this Agreement by the Master
      Servicer and its performance and compliance with the terms of this
      Agreement will not violate the Master Servicer's corporate charter or
      by-laws or constitute a default (or an event which, with notice or lapse
      of time, or both, would constitute a default) under, or result in the
      breach of, any material contract, agreement or other instrument to which
      the Master Servicer is a party or which may be applicable to the Master
      Servicer or any of its assets;

            (iii) This Agreement, assuming due authorization, execution and
      delivery by the Trustee and the Depositor, constitutes a valid, legal and
      binding obligation of the Master Servicer, enforceable against it in
      accordance with the terms hereof subject to applicable bankruptcy,
      insolvency, reorganization, moratorium and other laws affecting the
      enforcement of creditors' rights generally and to general principles of
      equity, regardless of whether such enforcement is considered in a
      proceeding in equity or at law;

            (iv) The Master Servicer is not in default with respect to any order
      or decree of any court or any order, regulation or demand of any federal,
      state, municipal or governmental agency, which default might have
      consequences that would materially and adversely affect the condition
      (financial or other) or operations of the Master Servicer or its
      properties or might have consequences that would materially affect its
      performance hereunder;

            (v) Except as otherwise disclosed in the Prospectus, no legal or
      governmental proceedings are pending (or known to be contemplated) against
      the Master Servicer that would be material to Certificateholders;

            (vi) Except as otherwise disclosed in the Prospectus, the Master
      Servicer is not aware and has not received notice that any default, early
      amortization or other performance triggering event has occurred as to any
      other securitization due to any act or failure to act of the Master
      Servicer under such securitization;

            (vii) Except as otherwise disclosed in the Prospectus, the Master
      Servicer has not been terminated as master servicer in a residential
      mortgage loan securitization, either due to a master servicing default or
      to application of a master servicing performance test or trigger;

            (viii) Except as otherwise disclosed in the Prospectus, no material
      noncompliance with the applicable servicing criteria with respect to other
      securitizations of residential mortgage loans involving the Master
      Servicer as a master servicer has been disclosed or reported by the Master
      Servicer within the past three (3) years;

            (ix) Except as otherwise disclosed in the Prospectus, no material
      changes to the Master Servicer's policies or procedures with respect to
      the master servicing function it will perform under this Agreement for
      mortgage loans of a type similar to the Mortgage Loans have occurred
      during the three-year period immediately preceding the date of this
      Agreement;

            (x) Except as otherwise disclosed in the Prospectus, there is no
      material risk that the Master Servicer's financial condition could affect
      one or more aspects of the performance by the Master Servicer of its
      master servicing obligations under this Agreement in a manner that could
      have a material impact on the performance of the Mortgage Loans or the
      Certificates; and

            (xi) Except as disclosed in the Prospectus, there are no
      affiliations, relationships or transactions relating to the Master
      Servicer and any party identified in Item 1119 of Regulation AB of the
      type described therein.

      It is understood and agreed that the representations and warranties set
forth in this Section 2.03(a) shall survive delivery of the respective Owner
Mortgage Loan Files to the Trustee or the Custodian. Upon discovery by any of
the Depositor, the Master Servicer or the Trustee of a breach of any of the
representations and warranties set forth in this Section 2.03(a), the party
discovering such breach shall give prompt written notice, which shall not exceed
two days, to the other parties. The Master Servicer shall consult with the
Depositor to determine if any such breach is material and any breach determined
by the Depositor to be material shall be included by the Master Servicer on the
next Distribution Date Statement prepared pursuant to Section 4.04.

      (b) The Depositor hereby represents and warrants to the Trustee for the
benefit of Certificateholders that, as of the date of execution of this
Agreement, with respect to the Mortgage Loans, or each Mortgage Loan, as the
case may be:

            (i) The information set forth in the Mortgage Loan Schedule was true
      and correct in all material respects at the date or dates respecting which
      such information is furnished as specified in the Mortgage Loan Schedule;

            (ii) Immediately prior to the transfer and assignment contemplated
      herein, the Depositor was the sole owner and holder of the Mortgage Loan
      free and clear of any and all liens, pledges, charges or security
      interests of any nature and has full right and authority to sell and
      assign the same;

            (iii) The Mortgage is a valid, subsisting and enforceable first lien
      on the property therein described, and the Mortgaged Property is free and
      clear of all encumbrances and liens having priority over the first lien of
      the Mortgage except for liens for real estate taxes and special
      assessments not yet due and payable and liens or interests arising under
      or as a result of any federal, state or local law, regulation or ordinance
      relating to hazardous wastes or hazardous substances, and, if the related
      Mortgaged Property is a condominium unit, any lien for common charges
      permitted by statute or homeowners association fees; and if the Mortgaged
      Property consists of shares of a cooperative housing corporation, any lien
      for amounts due to the cooperative housing corporation for unpaid
      assessments or charges or any lien of any assignment of rents or
      maintenance expenses secured by the real property owned by the cooperative
      housing corporation; and any security agreement, chattel mortgage or
      equivalent document related to, and delivered to the Trustee or to the
      Custodian with, any Mortgage establishes in the Depositor a valid and
      subsisting first lien on the property described therein and the Depositor
      has full right to sell and assign the same to the Trustee;

            (iv) Neither the Depositor nor any prior holder of the Mortgage or
      the related Mortgage Note has modified the Mortgage or the related
      Mortgage Note in any material respect, satisfied, canceled or subordinated
      the Mortgage in whole or in part, released the Mortgaged Property in whole
      or in part from the lien of the Mortgage, or executed any instrument of
      release, cancellation, modification or satisfaction, except in each case
      as is reflected in an agreement delivered to the Trustee or the Custodian
      pursuant to Section 2.01(a);

            (v) All taxes, governmental assessments, insurance premiums, and
      water, sewer and municipal charges, which previously became due and owing
      have been paid, or an escrow of funds has been established, to the extent
      permitted by law, in an amount sufficient to pay for every such item which
      remains unpaid; and the Depositor has not advanced funds, or received any
      advance of funds by a party other than the Mortgagor, directly or
      indirectly (except pursuant to any Subsidy Loan arrangement) for the
      payment of any amount required by the Mortgage, except for interest
      accruing from the date of the Mortgage Note or date of disbursement of the
      Mortgage Loan proceeds, whichever is later, to the day which precedes by
      thirty days the first Due Date under the related Mortgage Note;

            (vi) The Mortgaged Property is undamaged by water, fire, earthquake,
      earth movement other than earthquake, windstorm, flood, tornado or similar
      casualty (excluding casualty from the presence of hazardous wastes or
      hazardous substances, as to which the Depositor makes no representations),
      in a manner which would adversely affect the value of the Mortgaged
      Property as security for the Mortgage Loan or the use for which the
      premises were intended and to the best of the Depositor's knowledge, there
      is no proceeding pending or threatened for the total or partial
      condemnation of the Mortgaged Property;

            (vii) The Mortgaged Property is free and clear of all mechanics' and
      materialmen's liens or liens in the nature thereof; provided, however,
      that this warranty shall be deemed not to have been made at the time of
      the initial issuance of the Certificates if a title policy affording, in
      substance, the same protection afforded by this warranty is furnished to
      the Trustee by the Depositor;

            (viii) Except for Mortgage Loans secured by Co-op Shares and
      Mortgage Loans secured by residential long-term leases, the Mortgaged
      Property consists of a fee simple estate in real property; all of the
      improvements which are included for the purpose of determining the
      appraised value of the Mortgaged Property lie wholly within the boundaries
      and building restriction lines of such property and no improvements on
      adjoining properties encroach upon the Mortgaged Property (unless insured
      against under the related title insurance policy); and to the best of the
      Depositor's knowledge, the Mortgaged Property and all improvements thereon
      comply with all requirements of any applicable zoning and subdivision laws
      and ordinances;

            (ix) The Mortgage Loan meets, or is exempt from, applicable state,
      federal or local laws, regulations and other requirements, pertaining to
      usury, and the Mortgage Loan is not usurious;

            (x) To the best of the Depositor's knowledge, all inspections,
      licenses and certificates required to be made or issued with respect to
      all occupied portions of the Mortgaged Property and, with respect to the
      use and occupancy of the same, including, but not limited to, certificates
      of occupancy and fire underwriting certificates, have been made or
      obtained from the appropriate authorities;

            (xi) All payments required to be made up to the Due Date immediately
      preceding the Cut-Off Date for such Mortgage Loan under the terms of the
      related Mortgage Note have been made and no Mortgage Loan had more than
      one delinquency in the 12 months preceding the Cut-Off Date;

            (xii) The Mortgage Note, the related Mortgage and other agreements
      executed in connection therewith are genuine, and each is the legal, valid
      and binding obligation of the maker thereof, enforceable in accordance
      with its terms, except as such enforcement may be limited by bankruptcy,
      insolvency, reorganization or other similar laws affecting the enforcement
      of creditors' rights generally and by general equity principles
      (regardless of whether such enforcement is considered in a proceeding in
      equity or at law); and, to the best of the Depositor's knowledge, all
      parties to the Mortgage Note and the Mortgage had legal capacity to
      execute the Mortgage Note and the Mortgage and each Mortgage Note and
      Mortgage has been duly and properly executed by the Mortgagor;

            (xiii) Each Mortgage Loan at the time it was originated complied in
      all material respects with applicable federal, state and local laws
      including, without limitation, truth-in-lending, real estate settlement
      procedures, consumer credit protection, equal credit opportunity,
      predatory and abusive lending laws and disclosure laws;

            (xiv) The proceeds of the Mortgage Loans have been fully disbursed,
      there is no requirement for future advances thereunder and any and all
      requirements as to completion of any on-site or off-site improvements and
      as to disbursements of any escrow funds therefor have been complied with
      (except for escrow funds for exterior items which could not be completed
      due to weather and escrow funds for the completion of swimming pools); and
      all costs, fees and expenses incurred in making, closing or recording the
      Mortgage Loan have been paid, except recording fees with respect to
      Mortgages not recorded as of the Closing Date;

            (xv) The Mortgage Loan (except any Mortgage Loan secured by a
      Mortgaged Property located in any jurisdiction, as to which an opinion of
      counsel of the type customarily rendered in such jurisdiction in lieu of
      title insurance is instead received) is covered by an American Land Title
      Association mortgagee title insurance policy or other generally acceptable
      form of policy or insurance acceptable to Fannie Mae or Freddie Mac,
      issued by a title insurer acceptable to Fannie Mae or Freddie Mac insuring
      the originator, its successors and assigns, as to the first priority lien
      of the Mortgage in the original principal amount of the Mortgage Loan and
      subject only to (A) the lien of current real property taxes and
      assessments not yet due and payable, (B) covenants, conditions and
      restrictions, rights of way, easements and other matters of public record
      as of the date of recording of such Mortgage acceptable to mortgage
      lending institutions in the area in which the Mortgaged Property is
      located or specifically referred to in the appraisal performed in
      connection with the origination of the related Mortgage Loan, (C) liens
      created pursuant to any federal, state or local law, regulation or
      ordinance affording liens for the costs of clean-up of hazardous
      substances or hazardous wastes or for other environmental protection
      purposes and (D) such other matters to which like properties are commonly
      subject which do not individually, or in the aggregate, materially
      interfere with the benefits of the security intended to be provided by the
      Mortgage; the Depositor is the sole insured of such mortgagee title
      insurance policy, the assignment to the Trustee of the Depositor's
      interest in such mortgagee title insurance policy does not require any
      consent of or notification to the insurer which has not been obtained or
      made, such mortgagee title insurance policy is in full force and effect
      and will be in full force and effect and inure to the benefit of the
      Trustee, no claims have been made under such mortgagee title insurance
      policy, and no prior holder of the related Mortgage, including the
      Depositor, has done, by act or omission, anything which would impair the
      coverage of such mortgagee title insurance policy;

            (xvi) The Mortgaged Property securing each Mortgage Loan is insured
      by an insurer acceptable to Fannie Mae or Freddie Mac against loss by fire
      and such hazards as are covered under a standard extended coverage
      endorsement, in an amount which is not less than the lesser of 100% of the
      insurable value of the Mortgaged Property and the outstanding principal
      balance of the Mortgage Loan, but in no event less than the minimum amount
      necessary to fully compensate for any damage or loss on a replacement cost
      basis; if the Mortgaged Property is a condominium unit, it is included
      under the coverage afforded by a blanket policy for the project; if upon
      origination of the Mortgage Loan, the improvements on the Mortgaged
      Property were in an area identified in the Federal Register by the Federal
      Emergency Management Agency as having special flood hazards, a flood
      insurance policy meeting the requirements of the current guidelines of the
      Federal Insurance Administration is in effect with a generally acceptable
      insurance carrier, in an amount representing coverage not less than the
      least of (A) the outstanding principal balance of the Mortgage Loan, (B)
      the full insurable value of the Mortgaged Property and (C) the maximum
      amount of insurance which was available under the National Flood Insurance
      Act of 1968, as amended; and each Mortgage obligates the Mortgagor
      thereunder to maintain all such insurance at the Mortgagor's cost and
      expense;

            (xvii) To the best of the Depositor's knowledge, there is no
      default, breach, violation or event of acceleration existing under the
      Mortgage or the related Mortgage Note and no event which, with the passage
      of time or with notice and the expiration of any grace or cure period,
      would constitute a default, breach, violation or event of acceleration;
      the Depositor has not waived any default, breach, violation or event of
      acceleration; and no foreclosure action is currently threatened or has
      been commenced with respect to the Mortgage Loan;

            (xviii) No Mortgage Note or Mortgage is subject to any right of
      rescission, set-off, counterclaim or defense, including the defense of
      usury, nor will the operation of any of the terms of the Mortgage Note or
      Mortgage, or the exercise of any right thereunder, render the Mortgage
      Note or Mortgage unenforceable, in whole or in part, or subject it to any
      right of rescission, set-off, counterclaim or defense, including the
      defense of usury, and no such right of rescission, set-off, counterclaim
      or defense has been asserted with respect thereto;

            (xix) Each Mortgage Note is payable in monthly payments, resulting
      in complete amortization of the Mortgage Loan over a term of not more than
      360 months;

            (xx) Each Mortgage contains customary and enforceable provisions
      such as to render the rights and remedies of the holder thereof adequate
      for the realization against the Mortgaged Property of the benefits of the
      security, including realization by judicial foreclosure (subject to any
      limitation arising from any bankruptcy, insolvency or other law for the
      relief of debtors), and there is no homestead or other exemption available
      to the Mortgagor which would interfere with such right of foreclosure;

            (xxi) To the best of the Depositor's knowledge, no Mortgagor is a
      debtor in any state or federal bankruptcy or insolvency proceeding;

            (xxii) Each Mortgaged Property is located in the United States and
      consists of a one- to four-unit residential property, which may include a
      detached home, townhouse, condominium unit or a unit in a planned unit
      development or, in the case of Mortgage Loans secured by Co-op Shares,
      leases or occupancy agreements;

            (xxiii) The Mortgage Loan is a "qualified mortgage" within the
      meaning of Section 860G(a)(3) of the Code;

            (xxiv) With respect to each Mortgage where a lost note affidavit has
      been delivered to the Custodian in place of the related Mortgage Note, the
      related Mortgage Note is no longer in existence;

            (xxv) In the event that the Mortgagor is an inter vivos "living"
      trust, (i) such trust is in compliance with Fannie Mae or Freddie Mac
      standards for inter vivos trusts and (ii) holding title to the Mortgaged
      Property in such trust will not diminish any rights as a creditor
      including the right to full title to the Mortgaged Property in the event
      foreclosure proceedings are initiated;

            (xxvi) If the Mortgage Loan is secured by a long-term residential
      lease, (1) the lessor under the lease holds a fee simple interest in the
      land; (2) the terms of such lease expressly permit the mortgaging of the
      leasehold estate, the assignment of the lease without the lessor's consent
      and the acquisition by the holder of the Mortgage of the rights of the
      lessee upon foreclosure or assignment in lieu of foreclosure or provide
      the holder of the Mortgage with substantially similar protections; (3) the
      terms of such lease do not (a) allow the termination thereof upon the
      lessee's default without the holder of the Mortgage being entitled to
      receive written notice of, and opportunity to cure, such default, (b)
      allow the termination of the lease in the event of damage or destruction
      as long as the Mortgage is in existence, (c) prohibit the holder of the
      Mortgage from being insured (or receiving proceeds of insurance) under the
      hazard insurance policy or policies relating to the Mortgaged Property or
      (d) permit any increase in rent other than pre-established increases set
      forth in the lease; (4) the original term of such lease is not less than
      15 years; (5) the term of such lease does not terminate earlier than five
      years after the maturity date of the Mortgage Note; and (6) the Mortgaged
      Property is located in a jurisdiction in which the use of leasehold
      estates in transferring ownership in residential properties is a widely
      accepted practice;

            (xxvii) No Mortgage Loan is a "high cost" loan as defined under any
      federal, state or local law applicable to such Mortgage Loan at the time
      of its origination;

            (xxviii) No Mortgage Loan is serviced by the Trustee or an affiliate
      of the Trustee; and

            (xxix) No Mortgage Loan (other than a Mortgage Loan that is a New
      Jersey covered purchase loan) is a High Cost Loan or Covered Loan, as
      applicable (as such terms are defined in the then current S&P's LEVELS(R)
      Glossary which is now Version 5.6(d), Appendix E) and no Mortgage Loan
      originated on or after October 1, 2002 through March 6, 2003 is governed
      by the Georgia Fair Lending Act.

      Notwithstanding the foregoing, no representations or warranties are made
by the Depositor as to the environmental condition of any Mortgaged Property;
the absence, presence or effect of hazardous wastes or hazardous substances on
any Mortgaged Property; any casualty resulting from the presence or effect of
hazardous wastes or hazardous substances on, near or emanating from any
Mortgaged Property; the impact on Certificateholders of any environmental
condition or presence of any hazardous substance on or near any Mortgaged
Property; or the compliance of any Mortgaged Property with any environmental
laws, nor is any agent, person or entity otherwise affiliated with the Depositor
authorized or able to make any such representation, warranty or assumption of
liability relative to any Mortgaged Property. In addition, no representations or
warranties are made by the Depositor with respect to the absence or effect of
fraud in the origination of any Mortgage Loan.

      It is understood and agreed that the representations and warranties set
forth in this Section 2.03(b) shall survive delivery of the respective Owner
Mortgage Loan Files (and Retained Mortgage Loan Files, if applicable) to the
Custodian and shall inure to the benefit of the Trustee notwithstanding any
restrictive or qualified endorsement or assignment.

      (c) Upon discovery by any of the Depositor, the Master Servicer, the
Trustee or the Custodian that any of the representations and warranties made in
subsection (b) above is not accurate (referred to herein as a "breach") and,
except for a breach of the representation and warranty set forth in subsection
(b)(i), where such breach is a result of the Cut-Off Date Principal Balance of a
Mortgage Loan being greater, by $5,000 or greater, than the Cut-Off Date
Principal Balance of such Mortgage Loan indicated on the Mortgage Loan Schedule,
that such breach materially and adversely affects the interests of the
Certificateholders in the related Mortgage Loan, the party discovering such
breach shall give prompt written notice (not to exceed two days after discovery)
to the other parties to this Agreement and the Custodian (any Custodian being so
obligated under a Custodial Agreement). Within 60 days of the earlier of its
discovery or its receipt of notice of any such breach, the Depositor shall cure
such breach in all material respects or shall either (i) repurchase the Mortgage
Loan or any property acquired in respect thereof from the Trust Estate at a
price equal to the Repurchase Price or (ii) if within two years of the Startup
Day, or such other period permitted by the REMIC Provisions, substitute for such
Mortgage Loan in the manner described in Section 2.02. In addition to the
foregoing, if a breach of the representation set forth in clause (b)(xiii) or
(xxix) of this Section 2.03 occurs as a result of a violation of an applicable
predatory or abusive lending law, the Depositor shall reimburse the Trust for
all costs and damages including, but not limited to, reasonable attorneys' fees
and costs, incurred by the Trust as a result of the violation of such law (such
amount, the "Reimbursement Amount"). The Repurchase Price, the Substitution
Principal Amount, if any, plus accrued interest thereon and the other amounts
referred to in Section 2.02, and any Reimbursement Amount shall be deposited in
the Certificate Account. It is understood and agreed, except with respect to the
second preceding sentence, that the obligation of the Depositor to repurchase or
substitute for any Mortgage Loan or property as to which such a breach has
occurred and is continuing shall constitute the sole remedy respecting such
breach available to Certificateholders or the Trustee on behalf of
Certificateholders, and such obligation shall survive until termination of the
Trust Estate hereunder.

      The Trustee shall be responsible for enforcing the Depositor's obligations
under this Section 2.03. If the Trustee receives written notice from the Master
Servicer or the Custodian that such breach is not cured by the Depositor within
60 days after the Trustee's notice, the Trustee shall enforce the Depositor's
obligation to repurchase such Mortgage Loan or substitute for such Mortgage Loan
in accordance with the provisions of this Section 2.03. In connection with any
substitution permitted by this Section 2.03, the Master Servicer shall verify
that the unpaid principal balance and the Loan-to-Value Ratio of the Substitute
Mortgage Loan satisfy the requirements of this Section 2.03.

      Section 2.04 Execution and Delivery of Certificates.

      The Trustee acknowledges (i) the assignment to it of the Mortgage Loans
and (ii) the issuance of and hereby declares that it holds the Uncertificated
Lower-Tier Interests on behalf of the Upper-Tier REMIC and Certificateholders.
The Trustee acknowledges the delivery of the Owner Mortgage Loan Files to the
Custodian, on behalf of the Trustee. The Paying Agent, concurrently with such
delivery, has executed and delivered to or upon the order of the Depositor, in
exchange for the Mortgage Loans and Uncertificated Lower-Tier Interests,
together with all other assets included in the definition of "Trust Estate,"
receipt of which is hereby acknowledged, Certificates in authorized
denominations which, together with the Uncertificated Lower-Tier Interests,
evidence ownership of the entire Trust Estate.

      Section 2.05 Designation of Certificates; Designation of Startup Day and
Latest Possible Maturity Date.

      The Depositor hereby designates the Classes of Class A Certificates (other
than the Class I-A-R Certificate) and the Classes of Class B Certificates as
classes of "regular interests" and the Class I-A-R Interest as the single class
of "residual interest" in the Upper-Tier REMIC for the purposes of Code Sections
860G(a)(1) and 860G(a)(2), respectively. The Depositor hereby further designates
the Class I-A-L1 Interest, Class I-A-L5 Interest, Class I-A-LPO Interest, Class
I-A-LUR Interest, Class II-A-L1 Interest, Class II-A-L2 Interest, Class II-A-L3
Interest, Class II-A-LPO Interest, Class I-B-L1 Interest, Class I-B-L2 Interest,
Class I-B-L3 Interest, Class I-B-L4 Interest, Class I-B-L5 Interest, Class
I-B-L6 Interest, Class II-B-L1 Interest, Class II-B-L2 Interest, Class II-B-L3
Interest, Class II-B-L4 Interest, Class II-B-L5 Interest and Class II-B-L6
Interest as classes of "regular interests" and the Class I-A-LR Interest as the
single class of "residual interest" in the Lower-Tier REMIC for the purposes of
Code Sections 860G(a)(1) and 860G(a)(2), respectively. The Closing Date is
hereby designated as the "Startup Day" of each of the Upper-Tier REMIC and the
Lower-Tier REMIC within the meaning of Code Section 860G(a)(9). The "latest
possible maturity date" of the regular interests in the Upper-Tier REMIC and the
Lower-Tier REMIC is April 25, 2036 for purposes of Code Section 860G(a)(1).

                                   ARTICLE III

                  ADMINISTRATION OF THE TRUST ESTATE; SERVICING
                              OF THE MORTGAGE LOANS

      Section 3.01 Certificate Account.

      (a) The Master Servicer shall establish and maintain a Certificate Account
for the deposit of funds received by the Master Servicer with respect to the
Mortgage Loans serviced by each Servicer pursuant to each of the Servicing
Agreements. Such account shall be maintained as an Eligible Account. The Master
Servicer shall give notice to each Servicer and the Depositor of the location of
the Certificate Account and of any change in the location thereof.

      (b) The Master Servicer shall deposit into the Certificate Account on the
day of receipt thereof all amounts received by it from any Servicer pursuant to
any of the Servicing Agreements and amounts received from draws on any Letters
of Credit and shall, in addition, deposit into the Certificate Account the
following amounts, in the case of amounts specified in clauses (i) and (iii),
not later than the Business Day preceding the Distribution Date on which such
amounts are required to be distributed to Certificateholders and, in the case of
the amounts specified in clause (ii), not later than the Business Day next
following the day of receipt and posting by the Master Servicer:

            (i) Periodic Advances pursuant to Section 3.03(a) made by the Master
      Servicer or the Trustee, if any and any amounts deemed received by the
      Master Servicer pursuant to Section 3.01(d);

            (ii) in the case of any Mortgage Loan that is repurchased by the
      Depositor pursuant to Section 2.02, 2.03, 3.08 or 9.01 or that is
      auctioned by the Master Servicer pursuant to Section 3.08, the purchase
      price therefor or, where applicable, any Substitution Principal Amount and
      any amounts received in respect of the interest portion of unreimbursed
      Periodic Advances; and

            (iii) any Compensating Interest for such Distribution Date.

      (c) The Master Servicer may cause the funds in the Certificate Account to
be invested in Eligible Investments. No such Eligible Investments will be sold
or disposed of at a gain prior to maturity unless the Master Servicer has
received an Opinion of Counsel or other evidence satisfactory to it that such
sale or disposition will not cause either of the Upper-Tier REMIC or the
Lower-Tier REMIC to be subject to Prohibited Transactions Tax, otherwise subject
the Trust Estate to tax, or cause the Trust Estate to fail to qualify as a REMIC
while any Certificates are outstanding. Any amounts deposited in the Certificate
Account prior to the Distribution Date may be invested for the account of the
Master Servicer and any investment income thereon shall be additional
compensation to the Master Servicer for services rendered under this Agreement.
The amount of any losses incurred in respect of any such investments shall be
deposited in the Certificate Account by the Master Servicer out of its own funds
immediately as realized, without any right of reimbursement therefor from the
Trust Estate.

      (d) For purposes of this Agreement, the Master Servicer will be deemed to
have received from a Servicer on the applicable Remittance Date for such funds
all amounts deposited by such Servicer into the Custodial P&I Account maintained
in accordance with the applicable Servicing Agreement, if such Custodial P&I
Account is not an Eligible Account as defined in this Agreement, to the extent
such amounts are not actually received by the Master Servicer on such Remittance
Date as a result of the bankruptcy, insolvency, receivership or other financial
distress of the depository institution in which such Custodial P&I Account is
being held. To the extent that amounts so deemed to have been received by the
Master Servicer are subsequently remitted to the Master Servicer, the Master
Servicer shall be entitled to retain such amounts.

      Section 3.02 Permitted Withdrawals from the Certificate Account.

      (a) The Master Servicer may, from time to time, make withdrawals from the
Certificate Account for the following purposes (limited, in the case of Servicer
reimbursements, to cases where funds in the respective Custodial P&I Account are
not sufficient therefor):

            (i) to reimburse the Master Servicer, the Trustee or any Servicer
      for Periodic Advances made by the Master Servicer or the Trustee pursuant
      to Section 3.03(a) or any Servicer pursuant to any Servicing Agreement
      with respect to previous Distribution Dates, such right to reimbursement
      pursuant to this subclause (i) being limited to amounts received on or in
      respect of particular Mortgage Loans (including, for this purpose,
      Liquidation Proceeds, REO Proceeds and proceeds from the purchase, sale,
      repurchase or substitution of Mortgage Loans pursuant to Section 2.02,
      2.03, 3.08 or 9.01) respecting which any such Periodic Advance was made;

            (ii) to reimburse any Servicer, the Master Servicer or the Trustee
      for any Periodic Advances determined in good faith to have become
      Nonrecoverable Advances; provided, however, that any portion of
      Nonrecoverable Advances representing Fixed Retained Yield shall be
      reimbursable only from amounts constituting Fixed Retained Yield and not
      from assets of the Trust Estate;

            (iii) to reimburse the Master Servicer or any Servicer from
      Liquidation Proceeds for Liquidation Expenses and for amounts expended by
      the Master Servicer or any Servicer pursuant hereto or to any Servicing
      Agreement, respectively, in good faith in connection with the restoration
      of damaged property or for foreclosure expenses;

            (iv) from any Mortgagor payment on account of interest or other
      recovery (including Net REO Proceeds) with respect to a particular
      Mortgage Loan, to pay the Master Servicing Fee with respect to such
      Mortgage Loan to the Master Servicer;

            (v) to reimburse the Master Servicer, any Servicer or the Trustee
      (or, in certain cases, the Depositor) for expenses incurred by it
      (including taxes paid on behalf of the Trust Estate) and recoverable by or
      reimbursable to it pursuant to Section 3.03(c), Section 6.03, the second
      or third paragraphs of Section 8.06 or the third sentence of Section
      8.13(a) or pursuant to such Servicer's Servicing Agreement, provided such
      expenses are "unanticipated" within the meaning of the REMIC Provisions;

            (vi) to pay to the Depositor or other purchaser with respect to each
      Mortgage Loan or property acquired in respect thereof that has been
      repurchased or replaced pursuant to Section 2.02, 2.03, 3.08 or 9.01 or
      auctioned pursuant to Section 3.08, all amounts received thereon and not
      required to be distributed as of the date on which the related repurchase
      or purchase price or Scheduled Principal Balance was determined;

            (vii) to remit funds to the Paying Agent in the amounts and in the
      manner provided for herein;

            (viii) to pay to the Master Servicer any interest earned on or
      investment income with respect to funds in the Certificate Account;

            (ix) to pay to the Master Servicer or any Servicer out of
      Liquidation Proceeds allocable to interest the amount of any unpaid Master
      Servicing Fee or Servicing Fee (as adjusted pursuant to the related
      Servicing Agreement) and any unpaid assumption fees, late payment charges
      or other Mortgagor charges on the related Mortgage Loan;

            (x) to pay to the Master Servicer as additional master servicing
      compensation any Liquidation Profits which a Servicer is not entitled to
      pursuant to the applicable Servicing Agreement;

            (xi) to withdraw from the Certificate Account any amount deposited
      in the Certificate Account that was not required to be deposited therein;

            (xii) to clear and terminate the Certificate Account pursuant to
      Section 9.01; and

            (xiii) to pay to Wells Fargo Bank from any Mortgagor payment on
      account of interest or other recovery (including Net REO Proceeds) with
      respect to a particular Mortgage Loan, the Fixed Retained Yield, if any,
      with respect to such Mortgage Loan; provided, however, that with respect
      to any payment of interest received by the Master Servicer in respect of a
      Mortgage Loan (whether paid by the Mortgagor or received as Liquidation
      Proceeds, Insurance Proceeds or otherwise) which is less than the full
      amount of interest then due with respect to such Mortgage Loan, only that
      portion of such payment of interest that bears the same relationship to
      the total amount of such payment of interest as the Fixed Retained Yield
      Rate, if any, in respect of such Mortgage Loan bears to the Mortgage
      Interest Rate shall be allocated to the Fixed Retained Yield with respect
      thereto.

      (b) The Master Servicer shall keep and maintain separate accounting, on a
Mortgage Loan by Mortgage Loan basis, for the purpose of justifying any payment
to and withdrawal from the Certificate Account. The Master Servicer shall notify
the Depositor and the Trustee of the amount, purpose and party paid pursuant to
Section 3.02(a)(v).

      Section 3.03 Advances by Master Servicer and Trustee.

      (a) In the event an Other Servicer fails to make any required Periodic
Advances of principal and interest on a Mortgage Loan as required by the related
Other Servicing Agreement prior to the Business Day preceding the Distribution
Date occurring in the month during which such Periodic Advance is due, the
Master Servicer shall make Periodic Advances to the extent provided hereby. In
the event Wells Fargo Bank in its capacity as Servicer fails to make any
required Periodic Advances of principal and interest on a Mortgage Loan as
required by the Wells Fargo Bank Servicing Agreement prior to the Business Day
preceding the Distribution Date occurring in the month during which such
Periodic Advance is due, the Trustee shall, to the extent required by Section
8.14, make such Periodic Advance to the extent provided hereby, provided that
the Trustee has previously received the certificate of the Master Servicer
described in the following sentence and then, so long as such failure to advance
shall not have been remedied by 5:00 PM New York time on the Business Day
following notice provided by the Trustee to Wells Fargo Bank, the Trustee may
terminate the rights and obligations of Wells Fargo Bank in accordance with the
provisions of the Wells Fargo Bank Servicing Agreement. The Master Servicer
shall certify to the Trustee with respect to any such Distribution Date (i) the
amount of Periodic Advances required of Wells Fargo Bank in its capacity as
Servicer or such Other Servicer, as the case may be, (ii) the amount actually
advanced by Wells Fargo Bank in its capacity as Servicer or such Other Servicer,
(iii) the amount that the Trustee or Master Servicer is required to advance
hereunder and (iv) whether the Master Servicer has determined that it reasonably
believes that such Periodic Advance is a Nonrecoverable Advance. Amounts
advanced by the Trustee or Master Servicer shall be deposited in the Certificate
Account on the Business Day preceding the related Distribution Date.
Notwithstanding the foregoing, neither the Master Servicer nor the Trustee will
be obligated to make a Periodic Advance that it reasonably believes to be a
Nonrecoverable Advance. The Trustee may conclusively rely for any determination
to be made by it hereunder upon the determination of the Master Servicer as set
forth in its certificate.

      (b) To the extent an Other Servicer fails to make an advance on account of
the taxes or insurance premiums with respect to a Mortgage Loan required
pursuant to the related Other Servicing Agreement, the Master Servicer shall, if
the Master Servicer has actual knowledge of such failure of the Servicer,
advance such funds and take such steps as are necessary to pay such taxes or
insurance premiums. To the extent Wells Fargo Bank in its capacity as Servicer
fails to make an advance on account of the taxes or insurance premiums with
respect to a Mortgage Loan required pursuant to the Wells Fargo Bank Servicing
Agreement, the Master Servicer shall, if the Master Servicer knows of such
failure of Wells Fargo Bank in its capacity as Servicer, certify to the Trustee
that such failure has occurred. Upon receipt of such certification, the Trustee
shall advance such funds and take such steps as are necessary to pay such taxes
or insurance premiums.

      (c) The Master Servicer and the Trustee shall each be entitled to be
reimbursed from the Certificate Account for any Periodic Advance made by it
under Section 3.03(a) to the extent described in Section 3.02(a)(i) and (a)(ii).
The Master Servicer and the Trustee shall be entitled to be reimbursed pursuant
to Section 3.02(a)(v) for any advance by it pursuant to Section 3.03(b). The
Master Servicer shall diligently pursue restoration of such amount to the
Certificate Account from the related Servicer. The Master Servicer shall, to the
extent it has not already done so, upon the request of the Trustee, withdraw
from the Certificate Account and remit to the Trustee any amounts to which the
Trustee is entitled as reimbursement pursuant to Section 3.02 (a)(i), (ii) and
(v).

      (d) Except as provided in Section 3.03(a) and (b), neither the Master
Servicer nor the Trustee shall be required to pay or advance any amount which
any Servicer was required, but failed, to deposit in the Certificate Account.

      Section 3.04 Custodian to Cooperate; Release of Owner Mortgage Loan Files
and Retained Mortgage Loan Files.

      In connection with the deposit by a Servicer into the Certificate Account
of the proceeds from a Liquidated Loan or of a Prepayment in Full, the Master
Servicer or applicable Servicer shall confirm that all amounts required to be
remitted to the Certificate Account in connection with such Mortgage Loan have
been so deposited, and the Master Servicer or applicable Servicer shall deliver
two copies of any related Request for Release to the Custodian. The Custodian
shall, within five Business Days of its receipt of such a Request for Release,
release the related Owner Mortgage Loan File (and Retained Mortgage Loan File,
if applicable) to the Master Servicer or such Servicer, as requested by the
Master Servicer or such Servicer. No expenses incurred in connection with any
instrument of satisfaction or deed of reconveyance shall be chargeable to the
Certificate Account.

      From time to time and as appropriate for the servicing or foreclosure of
any Mortgage Loan, including but not limited to, collection under any insurance
policies, or to effect a partial release of any Mortgaged Property from the lien
of the Mortgage, the Servicer of such Mortgage Loan shall deliver to the Master
Servicer or Custodian two copies of a Request for Release. Upon the Master
Servicer's receipt of any such Request for Release, the Master Servicer shall
promptly forward such request in hard copy or in electronic format acceptable to
the Custodian. The Custodian shall, within five Business Days, release the
related Owner Mortgage Loan File (and Retained Mortgage Loan File, if
applicable) to the Master Servicer or such Servicer. Any such Request for
Release shall obligate the Master Servicer or such Servicer, as the case may be,
to return the Owner Mortgage Loan File (and Retained Mortgage Loan File, if
applicable) to the Custodian by the sixtieth day following the release thereof,
unless (i) the Mortgage Loan has been liquidated and the Liquidation Proceeds
relating to the Mortgage Loan have been deposited in the Certificate Account or
(ii) the Owner Mortgage Loan File (and Retained Mortgage Loan File, if
applicable) or such document has been delivered to an attorney, or to a public
trustee or other public official as required by law, for purposes of initiating
or pursuing legal action or other proceedings for the foreclosure of the
Mortgaged Property either judicially or non-judicially. Upon receipt of two
copies of a Request for Release stating that such Mortgage Loan was liquidated
and that all amounts received or to be received in connection with such
liquidation which are required to be deposited into the Certificate Account have
been so deposited, or that such Mortgage Loan has become an REO Mortgage Loan,
the Custodian shall amend its records.

      Upon the occurrence of the event specified in clause (ii) of the preceding
paragraph, the Trustee shall execute and deliver to the Master Servicer or such
Servicer, as directed by the Master Servicer, court pleadings, requests for
trustee's sale or other documents necessary to the foreclosure or trustee's sale
in respect of a Mortgaged Property or to any legal action brought to obtain
judgment against any Mortgagor on the Mortgage Note or Mortgage or to obtain a
deficiency judgment, or to enforce any other remedies or rights provided by the
Mortgage Note or Mortgage or otherwise available at law or in equity. Each such
certification shall include a request that such pleadings or documents be
executed by the Trustee and a statement as to the reason such documents or
pleadings are required and that the execution and delivery thereof by the
Trustee will not invalidate or otherwise affect the lien of the Mortgage, except
for the termination of such a lien upon completion of the foreclosure proceeding
or trustee's sale.

      Section 3.05 Reports to the Trustee; Annual Compliance Statements.

      The Master Servicer shall deliver in electronic form, or otherwise make
available to the Depositor, and the Master Servicer shall cause each Additional
Master Servicer engaged by it and each Servicer to deliver, in electronic form,
or otherwise make available, to the Master Servicer, the Trustee and each Rating
Agency on or before March 5 of each year or if such day is not a Business Day,
the next Business Day (with a 10 calendar day cure period, but in no event later
than March 15), commencing in March 2007, a copy of a certificate (followed by a
hard copy to the party or parties receiving such certificate within 10 calendar
days) in the form required by Item 1123 of Regulation AB, to the effect that (i)
an authorized officer of the Master Servicer, the Additional Master Servicer or
the Servicer, as the case may be, has reviewed (or a review has been made under
his or her supervision of) such party's activities under this Agreement or the
applicable Servicing Agreement, in the case of a Servicer, or such other
applicable agreement in the case of an Additional Master Servicer, during the
prior calendar year or portion thereof and (ii) to the best of such officer's
knowledge, based on such review, such party has fulfilled all of its obligations
under this Agreement or the applicable Servicing Agreement, in the case of a
Servicer, or such other applicable agreement in the case of an Additional Master
Servicer, in all material respects throughout the prior calendar year or portion
thereof or, if there has been a failure to fulfill any such obligation in any
material respect, specifying each such failure known to such officer and the
nature and status thereof. If any of the certificates delivered pursuant to this
Section 3.05 disclose that there has been a failure to fulfill any obligation in
any material respect then the Master Servicer shall promptly notify the
Depositor and forward a copy of such certificate to the Depositor, and the
Depositor shall review such certificate and, if applicable, consult with the
Master Servicer as to the nature of any failure to fulfill any obligation under
this Agreement or the applicable Servicing Agreement, in the case of a Servicer,
or such other applicable agreement in the case of an Additional Master Servicer,
in any material respect.

      Section 3.06 Title, Management and Disposition of Any REO Mortgage Loan.

      The Master Servicer shall enforce the obligations of the applicable
Servicer to administer each REO Mortgage Loan at all times so that each REO
Mortgage Loan qualifies as "foreclosure property" under the REMIC Provisions and
that it does not earn any "net income from foreclosure property" which is
subject to tax under the REMIC Provisions. In the event that a Servicer is
unable to dispose of any REO Mortgage Loan within the period mandated by each of
the Servicing Agreements, the Master Servicer shall monitor such Servicer to
verify that such REO Mortgage Loan is auctioned to the highest bidder within the
period so specified. In the event of any such sale of a REO Mortgage Loan, the
Custodian shall, at the written request of the Master Servicer and upon being
supported with appropriate forms therefor, within five Business Days of the
deposit by the Master Servicer of the proceeds of such sale or auction into the
Certificate Account, release or cause to be released to the entity identified by
the Master Servicer the related Owner Mortgage Loan File, Retained Mortgage Loan
File, if applicable, and Servicer Mortgage Loan File and shall execute and
deliver such instruments of transfer or assignment, in each case without
recourse, as shall be necessary to vest in the auction purchaser title to the
REO Mortgage Loan and the Custodian shall have no further responsibility with
regard to such Owner Mortgage Loan File, Retained Mortgage Loan File, if
applicable, or Servicer Mortgage Loan File. Neither the Trustee, the Master
Servicer nor any Servicer, acting on behalf of the Trust Estate, shall provide
financing from the Trust Estate to any purchaser of an REO Mortgage Loan.

      Section 3.07 Amendments to Servicing Agreements, Modification of Standard
Provisions.

      (a) Subject to the prior written consent of the Trustee pursuant to
Section 3.07(b) and the prior written consent of the Depositor, the Master
Servicer may, from time to time, to the extent permitted by the applicable
Servicing Agreement, make such modifications and amendments to such Servicing
Agreement as the Master Servicer deems necessary or appropriate to confirm or
carry out more fully the intent and purpose of such Servicing Agreement and the
duties, responsibilities and obligations to be performed by the Servicer
thereunder. Such modifications may only be made if they are consistent with the
REMIC Provisions, as evidenced by an Opinion of Counsel. Prior to the issuance
of any modification or amendment, the Master Servicer shall deliver to the
Trustee and the Depositor such Opinion of Counsel and an Officer's Certificate
setting forth (i) the provision that is to be modified or amended, (ii) the
modification or amendment that the Master Servicer desires to issue and (iii)
the reason or reasons for such proposed amendment or modification.

      (b) The Trustee shall consent to any amendment or supplement to a
Servicing Agreement proposed by the Master Servicer pursuant to Section 3.07(a),
which consent and amendment shall not require the consent of any
Certificateholder if it is (i) for the purpose of curing any mistake or
ambiguity, to further effect or protect the rights of the Certificateholders or
(ii) for any other purpose, provided such amendment or supplement for such other
purpose cannot reasonably be expected to adversely affect Certificateholders.
The lack of reasonable expectation of an adverse effect on Certificateholders
may be established through the delivery to the Trustee of (i) an Opinion of
Counsel to such effect or (ii) written notification from each Rating Agency to
the effect that such amendment or supplement will not result in reduction of the
current rating assigned by that Rating Agency to the Certificates.
Notwithstanding the two immediately preceding sentences, the Trustee may, in its
discretion, decline to enter into or consent to any such supplement or amendment
if its own rights, duties or immunities shall be adversely affected.

      (c)(i) Notwithstanding anything to the contrary in this Section 3.07, the
Master Servicer from time to time may, without the consent of any
Certificateholder or the Trustee, enter into an amendment (A) to an Other
Servicing Agreement for the purpose of (i) eliminating or reducing Month End
Interest and (ii) providing for the remittance of Full Unscheduled Principal
Receipts by the applicable Servicer to the Master Servicer not later than the
24th day of each month (or if such day is not a Business Day, on the previous
Business Day), (B) to the Wells Fargo Bank Servicing Agreement for the purpose
of changing the applicable Remittance Date to the 18th day of each month (or if
such day is not a Business Day, on the previous Business Day) or (C) to a
Servicing Agreement for the purpose of effecting or facilitating compliance by
the Servicer with Regulation AB or to conform a Servicing Agreement to industry
practices relating to Regulation AB.

      (ii) The Master Servicer may direct Wells Fargo Bank in its capacity as
Servicer to enter into an amendment to the Wells Fargo Bank Servicing Agreement
for the purposes described in Section 3.07(c)(i)(B) or (C).

      Section 3.08 Oversight of Servicing.

      The Master Servicer shall supervise, monitor and oversee the servicing of
the Mortgage Loans by each Servicer and the performance by each Servicer of all
services, duties, responsibilities and obligations (including the obligation to
maintain an Errors and Omissions Policy and Fidelity Bond) that are to be
observed or performed by the Servicer under its respective Servicing Agreement.
In performing its obligations hereunder, the Master Servicer shall act in a
manner consistent with Accepted Master Servicing Practices and in a manner
consistent with the terms and provisions of any insurance policy required to be
maintained by the Master Servicer or any Servicer pursuant to this Agreement or
any Servicing Agreement. The Master Servicer acknowledges that prior to taking
certain actions required to service the Mortgage Loans, each Servicing Agreement
provides that the Servicer thereunder must notify, consult with, obtain the
consent of, waiver from, or otherwise follow the instructions of the Master
Servicer. In the case of any request for waiver from a Servicer, the Master
Servicer shall promptly instruct such Servicer or otherwise respond to such
Servicer's request. The Master Servicer shall not waive compliance by a Servicer
with those provisions of its Servicing Agreement which are required to enable
the Depositor and the Master Servicer to satisfy the Trust's ongoing reporting
obligations under the Exchange Act. In addition, in no event will the Master
Servicer instruct such Servicer to take any action, give any consent to action
by such Servicer or waive compliance by such Servicer with any provision of such
Servicer's Servicing Agreement if any resulting action or failure to act would
be inconsistent with the requirements of the Rating Agencies that rated the
Certificates, would be inconsistent with the requirements of Regulation AB or
would otherwise have an adverse effect on the Certificateholders. Any such
action or failure to act shall be deemed to have an adverse effect on the
Certificateholders if such action or failure to act either results in (i) the
downgrading of the rating assigned by any Rating Agency to the Certificates,
(ii) the loss by the Upper-Tier REMIC or the Lower-Tier REMIC of REMIC status
for federal income tax purposes or (iii) the imposition of any Prohibited
Transaction Tax or any federal taxes on any of the Upper-Tier REMIC, the
Lower-Tier REMIC or the Trust Estate. The Master Servicer shall have full power
and authority in its sole discretion to take any action with respect to the
Trust Estate as may be necessary or advisable to avoid the circumstances
specified including clause (ii) or (iii) of the preceding sentence.

      For the purposes of determining whether any modification of a Mortgage
Loan shall be permitted by the Master Servicer, such modification shall be
construed as a substitution of the modified Mortgage Loan for the Mortgage Loan
originally deposited in the Trust Estate if it would be a "significant
modification" within the meaning of Section 1.860G-2(b) of the regulations of
the U.S. Department of the Treasury. No modification shall be approved unless
(i) the modified Mortgage Loan would qualify as a Substitute Mortgage Loan under
Section 2.02 and (ii) with respect to any modification that occurs more than
three months after the Closing Date and is not the result of a default or a
reasonably foreseeable default under the Mortgage Loan, there is delivered to
the Trustee an Opinion of Counsel (at the expense of the party seeking to modify
the Mortgage Loan) to the effect that such modification would not be treated as
giving rise to a new debt instrument for federal income tax purposes as
described in the preceding sentence; provided, however, that no such Opinion of
Counsel need be delivered if the sole purpose of the modification is to reduce
the Monthly Payment on a Mortgage Loan as a result of a Curtailment such that
the Mortgage Loan is fully amortized by its original maturity date.

      During the term of this Agreement, the Master Servicer shall consult fully
with each Servicer as may be necessary from time to time to perform and carry
out the Master Servicer's obligations hereunder and otherwise exercise
reasonable efforts to cause such Servicer to perform and observe the covenants,
obligations and conditions to be performed or observed by it under its Servicing
Agreement.

      The relationship of the Master Servicer to the Trustee under this
Agreement is intended by the parties to be that of an independent contractor and
not that of a joint venturer, partner or agent.

      The Master Servicer shall administer the Trust Estate on behalf of the
Trustee and shall have full power and authority, acting alone or (subject to the
requirements of Section 6.06) through one or more Subcontractors, to do any and
all things in connection with such administration which it may deem necessary or
desirable. Upon the execution and delivery of this Agreement, and from time to
time as may be required thereafter, the Trustee shall furnish the Master
Servicer or its Subcontractors with any powers of attorney and such other
documents as may be necessary or appropriate to enable the Master Servicer to
carry out its administrative duties hereunder.

      The Depositor shall have a limited option to repurchase any defaulted
Mortgage Loan or REO Mortgage Loan during the following time periods: (i)
beginning on the first day of the second month following the month in which the
Master Servicer has reported that a Servicer has initiated foreclosure
proceedings with respect to such a defaulted Mortgage Loan, with such repurchase
option expiring on the last day of such second following month; (ii) beginning
on the first day of the second month following the month in which the Master
Servicer has reported that such defaulted Mortgage Loan has become an REO
Mortgage Loan, with such repurchase option expiring on the last day of such
second following month; and (iii) beginning on the day on which a Servicer
accepts a contractual commitment by a third party to purchase the Mortgaged
Property related to the defaulted Mortgage Loan or REO Mortgage Loan, with such
repurchase option expiring on the earlier of the last day of the month in which
such contractual commitment was accepted by the Servicer or the day immediately
prior to the day on which the closing occurs with respect to such third party
purchase of the Mortgaged Property related to the defaulted Mortgage Loan or REO
Mortgage Loan. The Depositor shall be entitled to repurchase at its option any
Mortgage Loan in the Trust Estate which, pursuant to paragraph 5(b) of the
Mortgage Loan Purchase Agreement, Wells Fargo Bank requests the Depositor to
repurchase and to sell to Wells Fargo Bank to facilitate the exercise of Wells
Fargo Bank's rights against the originator or a prior holder of such Mortgage
Loan. The purchase price for any Mortgage Loan repurchased pursuant to this
paragraph shall be the Repurchase Price. Upon the receipt of the Repurchase
Price, the Master Servicer shall provide to the Trustee the certification
required by Section 3.04 and the Trustee and the Custodian, if any, shall
promptly release to the Depositor the Owner Mortgage Loan File and Retained
Mortgage Loan File, if applicable, relating to the Mortgage Loan being
repurchased.

      In the event that (i) the Master Servicer determines at any time that,
notwithstanding the representations and warranties set forth in Section 2.03(b),
any Mortgage Loan is not a "qualified mortgage" within the meaning of Section
860G of the Code and (ii) the Trustee is unable to enforce the obligation of the
Depositor to purchase such Mortgage Loan pursuant to Section 2.02 within two
months of such determination, the Master Servicer shall cause such Mortgage Loan
to be auctioned to the highest bidder and sold out of the Trust Estate no later
than the date 90 days after such determination. In the event of any such sale of
a Mortgage Loan, the Custodian shall, at the written request of the Master
Servicer and upon being supported with appropriate forms therefor, within five
Business Days of the deposit by the Master Servicer of the proceeds of such
auction into the Certificate Account, release or cause to be released to the
entity identified by the Master Servicer the related Owner Mortgage Loan File,
Retained Mortgage Loan File, if applicable, and Servicer Mortgage Loan File and
shall execute and deliver such instruments of transfer or assignment, in each
case without recourse, as shall be necessary to vest in the auction purchaser
title to the Mortgage Loan and the Custodian shall have no further
responsibility with regard to such Owner Mortgage Loan File, Retained Mortgage
Loan File, if applicable, or Servicer Mortgage Loan File. None of the Trustee,
the Custodian, the Master Servicer or any Servicer, acting on behalf of the
Trustee, shall provide financing from the Trust Estate to any purchaser of a
Mortgage Loan.

      The Master Servicer, on behalf of the Trustee, shall, pursuant to the
Servicing Agreements, object to the foreclosure upon, or other related
conversion of the ownership of, any Mortgaged Property by the related Servicer
if (i) the Master Servicer believes such Mortgaged Property may be contaminated
with or affected by hazardous wastes or hazardous substances or (ii) such
Servicer does not agree to administer such Mortgaged Property, once the related
Mortgage Loan becomes an REO Mortgage Loan, in a manner which would not result
in a federal tax being imposed upon the Trust Estate or the Upper-Tier REMIC or
the Lower-Tier REMIC.

      At the direction of the Depositor, the Master Servicer may enter into a
special servicing agreement with an unaffiliated holder of 100% Percentage
Interest of a Class of Class B Certificates or a holder of a class of securities
representing interests in the Class B Certificates and/or other subordinated
mortgage pass-through certificates (such entity, a "Special Servicer"), such
agreement (a "Special Servicing Agreement") to be substantially in the form of
Exhibit M hereto or subject to each Rating Agency's acknowledgment that the
ratings of the Certificates in effect immediately prior to the entering into of
such agreement would not be qualified, downgraded or withdrawn and the
Certificates would not be placed on credit review status (except for possible
upgrading) as a result of such agreement. Any such agreement may contain
provisions whereby such holder may (a) purchase any Mortgage Loans that are more
than 180 days delinquent and (b) instruct the Master Servicer to instruct a
Servicer to the extent provided in the applicable Servicing Agreement to
commence or delay foreclosure proceedings with respect to delinquent Mortgage
Loans and will contain provisions for the deposit of cash by the holder that
would be available for distribution to Certificateholders if Liquidation
Proceeds are less than they otherwise may have been had the Servicer acted in
accordance with its normal procedures.

      The Master Servicer shall monitor the rating of Wells Fargo & Company and
upon the occurrence of a Document Transfer Event relating to such rating, shall
promptly notify the Depositor, Trustee and Custodian of the occurrence of such
Document Transfer Event.

      Section 3.09 Termination and Substitution of Servicing Agreements.

      Upon the occurrence of any event for which a Servicer may be terminated
pursuant to its Servicing Agreement, the Master Servicer shall promptly deliver
to the Depositor and the Trustee an Officer's Certificate certifying that an
event has occurred which may justify termination of such Servicing Agreement,
describing the circumstances surrounding such event and recommending what action
should be taken by the Trustee with respect to such Servicer. If the Master
Servicer recommends that such Servicing Agreement be terminated, the Master
Servicer's certification must state that the breach is material and not merely
technical in nature. Based upon such certification, the Master Servicer, or if
provided by the applicable Other Servicing Agreement and upon written direction
of the Master Servicer, the Trustee, shall promptly terminate such Other
Servicing Agreement. The Trustee shall terminate the Wells Fargo Bank Servicing
Agreement in accordance with the provisions of Article 19 thereof. The Master
Servicer shall indemnify the Trustee and hold it harmless from and against any
and all claims, liabilities, costs and expenses (including, without limitation,
reasonable attorneys' fees) arising out of, or assessed against the Trustee in
connection with termination of a Servicing Agreement at the direction of the
Master Servicer except to the extent that such claims, liabilities, costs and
expenses are incurred as a result of the bad faith, willful misfeasance or gross
negligence of the Trustee in the performance of its obligations hereunder. To
the extent that the costs and expenses (including any amounts paid by the Master
Servicer pursuant to the immediately preceding sentence) of the Master Servicer
related to any termination of a Servicer, appointment of a successor Servicer or
the transfer and assumption of servicing by the Master Servicer with respect to
any Servicing Agreement (including, without limitation, (i) all legal costs and
expenses and all due diligence costs and expenses associated with an evaluation
of the potential termination of the Servicer as a result of an event of default
by such Servicer, (ii) all costs and expenses associated with the complete
transfer of servicing, including all servicing files and all servicing data and
the completion, correction or manipulation of such servicing data as may be
required by the successor servicer to correct any errors or insufficiencies in
the servicing data or otherwise to enable the successor servicer to service the
Mortgage Loans in accordance with the related Servicing Agreement and (iii) any
costs incurred by the Trustee in connection with a servicing transfer) are not
fully and timely reimbursed by the terminated Servicer, the Master Servicer
shall be entitled to reimbursement of such costs and expenses from the
Certificate Account. If the Master Servicer or Trustee terminates an Other
Servicing Agreement, the Trustee may enter into a substitute Servicing Agreement
with the Master Servicer or, at the Master Servicer's nomination, with another
mortgage loan service company acceptable to the Trustee, the Master Servicer and
each Rating Agency under which the Master Servicer or such substitute servicer,
as the case may be, shall assume, satisfy, perform and carry out all
liabilities, duties, responsibilities and obligations that are to be, or
otherwise were to have been, satisfied, performed and carried out by such
Servicer under such terminated Servicing Agreement. If the Trustee terminates
the Wells Fargo Bank Servicing Agreement, the Trustee shall enter into a
substitute Servicing Agreement with another mortgage loan service company
acceptable to the Trustee and each Rating Agency under which such substitute
servicer shall assume, satisfy, perform and carry out all liabilities, duties,
responsibilities and obligations that are to be, or otherwise were to have been,
satisfied, performed and carried out by Wells Fargo Bank, in its capacity as
Servicer, under such terminated Servicing Agreement. It is understood and
acknowledged by the parties hereto that there will be a period of transition not
to exceed ninety (90) days before the servicing functions can be transferred to
such substitute servicer. Until such time as the Trustee enters into a
substitute servicing agreement with respect to the Mortgage Loans previously
serviced by an Other Servicer and the transition period relating to the transfer
of such servicing expires, the Master Servicer shall assume, satisfy, perform
and carry out all obligations which otherwise were to have been satisfied,
performed and carried out by an Other Servicer under its terminated Servicing
Agreement. However, in no event shall the Master Servicer be deemed to have
assumed the obligations of a Servicer to advance payments of principal and
interest on a delinquent Mortgage Loan in excess of the Master Servicer's
independent Periodic Advance obligation under Section 3.03 of this Agreement. As
compensation for the Master Servicer of any servicing obligations fulfilled or
assumed by the Master Servicer, the Master Servicer shall be entitled to any
servicing compensation to which a Servicer would have been entitled if the
Servicing Agreement with such Servicer had not been terminated.

      Section 3.10 Application of Net Liquidation Proceeds.

      For all purposes under this agreement, Net Liquidation Proceeds received
from a Servicer shall be allocated first to accrued and unpaid interest on the
related Mortgage Loan and then to the unpaid principal balance thereof.

      Section 3.11 Assessment of Servicing Compliance; Registered Public
Accounting Firm Attestation Reports.

      (a) The Master Servicer, at its own expense, shall furnish to the
Depositor, and the Trustee, any Special Servicer (if applicable) and the
Custodian, at their own expense, shall furnish, or otherwise make available, and
shall cause any Servicing Function Participant engaged by any such party to
furnish, and the Master Servicer shall use reasonable effort to cause each
Servicer to furnish with respect to such Servicer and each Servicing Function
Participant engaged by such Servicer and identified to the Master Servicer, at
such party's expense, to the Master Servicer, not later than March 5 of each
year, or if such day is not a Business Day, the next Business Day (with a 10 day
cure period, but in no event later than March 15), commencing in March 2007, a
copy of a report, followed by a hard copy to the Master Servicer within 10
calendar days, signed by an authorized officer of the Master Servicer, the
Trustee, the Custodian, the Servicing Function Participant, the Special Servicer
(if applicable) or the Servicer, as applicable, on assessment of compliance
with, at a minimum, the Relevant Servicing Criteria that contains:

            (i) a statement by such party of its responsibility for assessing
      compliance with the Servicing Criteria applicable to it;

            (ii) a statement that such party used the Servicing Criteria
      applicable to it to assess compliance with the Servicing Criteria;

            (iii) such party's assessment of compliance with the Servicing
      Criteria applicable to it as of and for the preceding fiscal year,
      including, if there had been any material instance of noncompliance with
      the Servicing Criteria applicable to it, identifying each such failure and
      the nature and status thereof; and

            (iv) a statement that a registered public accounting firm has issued
      an attestation report on such party's assessment of compliance with the
      Servicing Criteria applicable to it as of and for the preceding fiscal
      year.

      No later than 30 days following the end of each fiscal year, the Master
Servicer shall forward to the Depositor the name of each Servicing Function
Participant engaged by it and what Relevant Servicing Criteria will be addressed
in the report on assessment of compliance prepared by such Servicing Function
Participant. When the Master Servicer submits its assessments to the Depositor,
it will also at such time include the assessment (and attestation pursuant to
Section 3.11(b)) of each Servicing Function Participant engaged by it.

      No later than 30 days following the end of each fiscal year, each of the
Trustee, any Special Servicer (if applicable) and the Custodian (so long as the
Custodian is not the Master Servicer) shall forward to the Master Servicer the
name of each Servicing Function Participant engaged by it and what Relevant
Servicing Criteria will be addressed in the report on assessment of compliance
prepared by such Servicing Function Participant. When the Trustee, any Special
Servicer (if applicable) and the Custodian (so long as the Custodian is not the
Master Servicer) submit their assessments to the Master Servicer, each such
party will also at such time include the assessment (and attestation pursuant to
Section 3.11(b)) of each Servicing Function Participant engaged by it.

      The Master Servicer shall confirm that the assessments address the
Relevant Servicing Criteria for each party as set forth on Exhibit R or in the
applicable Servicing Agreement or the applicable Special Servicing Agreement and
shall notify the Depositor of any exceptions and deliver the assessment of
compliance containing such exceptions. Promptly after receipt of each such
report on assessment of compliance, the Depositor shall review each such report
and, if applicable, consult with the Master Servicer, the Trustee, the
Custodian, any Special Servicer (if applicable) and any Servicing Function
Participant as to the nature of any material instance of noncompliance with the
Relevant Servicing Criteria by the Master Servicer, the Trustee, the Custodian,
any Servicer, any Special Servicer (if applicable), or any Servicing Function
Participant engaged by such parties.

      (b) The Master Servicer, at its own expense, shall cause a registered
public accounting firm which is a member of the Institute of Certified Public
Accountants to furnish to the Depositor, and each of the Trustee, the Custodian
and any Special Servicer (if applicable) at their own expense, shall cause, and
shall cause any Servicing Function Participant engaged by any such party, at
such party's expense, to cause, and the Master Servicer shall use reasonable
efforts to cause each Servicer, at such Servicer's expense, with respect to such
Servicer and each Servicing Function Participant engaged by such Servicer and
identified to the Master Servicer, to cause a registered public accounting firm
which is a member of the Institute of Certified Public Accountants to furnish to
the Master Servicer, not later than March 5 of each year, or if such day is not
a Business Day, the next Business Day (with a 10 calendar day cure period, but
in no event later than March 15), commencing in March 2007, an electronic report
(with a hard copy to follow within 10 calendar days) to the effect that (i) it
has obtained a representation regarding certain matters from the management of
such party, which includes an assertion that such party has complied with the
Relevant Servicing Criteria, and (ii) on the basis of an examination conducted
by such firm in accordance with standards for attestation engagements issued or
adopted by the Public Company Accounting Oversight Board, it is expressing an
opinion as to whether such party's assessment of compliance with the Relevant
Servicing Criteria was fairly stated in all material respects, or it cannot
express an overall opinion regarding such party's assessment of compliance with
the Relevant Servicing Criteria. In the event that an overall opinion cannot be
expressed, such registered public accounting firm shall state in such report why
it was unable to express such an opinion. Such report must be available for
general use and not contain restricted use language. If requested by the Master
Servicer or the Depositor, such report shall contain or be accompanied by a
consent of such accounting firm to inclusion or incorporation of such report in
the Depositor's Registration Statement on Form S-3 relating to the Certificates
and the Trust's Form 10-K.

      Promptly after receipt of such report from the Master Servicer, the
Depositor shall review the report and, if applicable, consult with the Master
Servicer if any such report (i) states that the party's assessment of compliance
was not fairly stated in a material respect or (ii) is unable to state an
overall opinion.

      Promptly after receipt of such report from the Trustee, the Custodian, the
Servicer, the Special Servicer (if applicable), or any Servicing Function
Participant engaged by such parties, the Master Servicer shall review the report
and shall promptly notify the Depositor if any such report (i) states that the
party's assessment of compliance was not fairly stated in a material respect or
(ii) is unable to state an overall opinion and the Depositor shall promptly
review each such report and the Depositor and the Master Servicer shall consult
with the parties to which such report relates.

      The Master Servicer shall make available any report from the Master
Servicer, the Trustee, the Custodian, the Servicer, the Special Servicer (if
applicable), or any Servicing Function Participant furnished pursuant to Section
3.05 and this Section 3.11, as well as any documents incorporated by reference
into the Prospectus (to the extent such documents are either in its possession
or have been filed with the Commission), to any Certificateholder requesting
such information.

      Section 3.12 Exchange Act Reports.

      (a) Within 15 days after each Distribution Date, the Master Servicer shall
prepare, an authorized officer of the Master Servicer shall sign, and the Master
Servicer shall file with the Commission, on behalf of the Trust, any Form 10-D
required by the Exchange Act, in form and substance as required by the Exchange
Act. The Master Servicer shall file each Form 10-D with a copy of the related
Distribution Date Statement attached thereto. Any disclosure in addition to the
Distribution Date Statement that is required to be included on Form 10-D
("Additional Form 10-D Disclosure") shall be reported by the parties set forth
on Exhibit S and directed and approved by the Depositor, and the Master Servicer
will have no duty or liability for any failure hereunder to determine or prepare
any Additional Form 10-D Disclosure (other than with respect to itself) absent
such reporting, direction and approval. If a Form 10-D cannot be filed on time
or if a previously filed Form 10-D needs to be amended, the Master Servicer will
follow the procedures set forth in Section 3.12(d). Promptly (but no later than
1 Business Day) after filing with the Commission, the Master Servicer will make
available on its internet website a final executed copy of each Form 10-D.

      For so long as the Trust is subject to the Exchange Act reporting
requirements, within five (5) calendar days after the related Distribution Date,
the parties identified on Exhibit S shall (i) provide to the Master Servicer and
the Depositor, to the extent known by a Responsible Officer, in EDGAR-compatible
format, or in such other format as otherwise agreed upon by the Master Servicer
and such party, the form and substance of any Additional Form 10-D Disclosure,
if applicable and (ii) include with such Additional Form 10-D Disclosure, an
Additional Disclosure Notification in the form attached hereto as Exhibit V, and
the Depositor will approve, as to form and substance, or disapprove, as the case
may be, the inclusion of the Additional Form 10-D Disclosure on Form 10-D. The
Master Servicer has no duty under this Agreement to monitor or enforce the
performance by the parties listed on Exhibit S of their duties under this
paragraph or proactively solicit or procure from such parties any Additional
Form 10-D Disclosure; except that the Master Servicer shall enforce the
obligations of the Servicers under the Servicing Agreements. After preparing the
Form 10-D, if the Form 10-D contains any Additional Form 10-D Disclosure, the
Master Servicer shall forward electronically a draft copy of the Form 10-D to
the Depositor for review. Each party to this Agreement acknowledges that the
performance by the Master Servicer of its duties under this Section 3.12(a)
relating to the timely preparation and filing of Form 10-D is contingent upon
such parties strictly observing all applicable deadlines in the performance of
their duties under this Section 3.12(a). The Master Servicer shall have no
liability for any loss, expense, damage, claim arising out of or with respect to
any failure to properly prepare and/or timely file such Form 10-D, where such
failure results from the Master Servicer's inability or failure to receive, on a
timely basis, any information from any other party hereto, any Servicer, the
Custodian or any Special Servicer (if applicable) needed to prepare, arrange for
execution or file such Form 10-D, not resulting from its own negligence, bad
faith or willful misconduct. The Depositor will be responsible for any
reasonable fees assessed and expenses incurred by the Master Servicer in
connection with including any Additional Form 10-D Disclosure on Form 10-D
pursuant to this paragraph.

      (b) Within 90 days after the end of each fiscal year of the Trust or such
earlier date as may be required by the Exchange Act (it being understood that
the fiscal year for the Trust ends on December 31st of each year), commencing in
March 2007, the Master Servicer shall prepare, a senior officer of the Master
Servicer in charge of the master servicing function shall sign, and the Master
Servicer shall file with the Commission, on behalf of the Trust, a Form 10-K, in
form and substance as required by the Exchange Act. Each such Form 10-K shall
include the following items, in each case to the extent they have been delivered
to the Master Servicer within the applicable timeframes set forth in this
Agreement, the related Servicing Agreements, the Custodial Agreement or, if
applicable, the Special Servicing Agreement:

            (i) an annual compliance statement for the Master Servicer, any
      Additional Master Servicer and each Servicer, as described under Section
      3.05;

            (ii) (A) the annual reports on assessment of compliance with
      servicing criteria for the Master Servicer, the Trustee, each Servicer,
      the Custodian, any Special Servicer (if applicable), and each Servicing
      Function Participant, as described under Section 3.11(a), and (B) if any
      party's report on assessment of compliance with Servicing Criteria
      described under Section 3.11(a) identifies any material instance of
      noncompliance, disclosure identifying such instance of noncompliance, or
      if any party's report on assessment of compliance with servicing criteria
      described under Section 3.11(a) is not included as an exhibit to such Form
      10-K, disclosure that such report is not included and an explanation of
      why such report is not included;

            (iii) (A) the registered public accounting firm attestation report
      for each of the Master Servicer, the Trustee, each Servicer, the
      Custodian, any Special Servicer (if applicable), and each Servicing
      Function Participant, as described under Section 3.11(b), and (B) if any
      registered public accounting firm attestation report described under
      Section 3.11(b) identifies any material instance of noncompliance,
      disclosure identifying such instance of noncompliance, or if any such
      registered public accounting firm attestation report is not included as an
      exhibit to such Form 10-K, disclosure that such report is not included and
      an explanation of why such report is not included; and

            (iv) a certification, signed by a senior officer of the Master
      Servicer in charge of the master servicing function, in the form attached
      hereto as Exhibit P or in such other form as may be required by Rules
      13a-14 and 15d-14 under the Exchange Act, as applicable, and any
      directives or interpretations thereof by the Commission (the
      "Sarbanes-Oxley Certification").

      Any disclosure or information in addition to (i) through (iv) above that
is required to be included on Form 10-K ("Additional Form 10-K Disclosure")
shall, pursuant to the paragraph immediately below, be reported by the parties
set forth on Exhibit T and directed and approved by the Depositor, and the
Master Servicer will have no duty or liability for any failure hereunder to
determine or prepare any Additional Form 10-K Disclosure (other than with
respect to itself) absent such reporting, direction and approval. If a Form 10-K
cannot be filed on time or if a previously filed Form 10-K needs to be amended,
the Master Servicer will follow the procedures set forth in Section 3.12(d).
Promptly (but no later than 1 Business Day) after filing with the Commission,
the Master Servicer will make available on its internet website a final executed
copy of each Form 10-K.

      No later than March 5 (with a 10 calendar day cure period, but in no event
later than March 15) of each year that the Trust is subject to the Exchange Act
reporting requirements, commencing in March 2007, (i) the parties identified on
Exhibit T shall provide to the Master Servicer and the Depositor, to the extent
known by a Responsible Officer, in EDGAR-compatible format, or in such other
format as otherwise agreed upon by the Master Servicer and such party, the form
and substance of any Additional Form 10-K Disclosure, if applicable, and (ii)
the parties identified on Exhibit T shall include with such Additional Form 10-K
Disclosure, an Additional Disclosure Notification in the form attached hereto as
Exhibit V, and the Depositor will approve, as to form and substance, or
disapprove, as the case may be, the inclusion of the Additional Form 10-K
Disclosure on Form 10-K. The Master Servicer has no duty under this Agreement to
monitor or enforce the performance by the parties listed on Exhibit T of their
duties under this paragraph or proactively solicit or procure from such parties
any Additional Form 10-K Disclosure information; except that the Master Servicer
shall enforce the obligations of the Servicers under the Servicing Agreements.
The Depositor will be responsible for any reasonable fees and expenses assessed
or incurred by the Master Servicer in connection with including any Additional
Form 10-K Disclosure on Form 10-K pursuant to this paragraph.

      After preparing the Form 10-K, if the Form 10-K contains any Additional
Form 10-K Disclosure, the Master Servicer shall forward electronically a draft
copy of the Form 10-K to the Depositor for review. Each party to this Agreement
acknowledges that the performance by the Master Servicer of its duties under
this Section 3.12(b) relating to the timely preparation and filing of Form 10-K
is contingent upon such parties strictly observing all applicable timeframes in
the performance of their duties under Sections 3.05, 3.11 or this Section
3.12(b). The Master Servicer shall have no liability for any loss, expense,
damage, claim arising out of or with respect to any failure to properly prepare
and/or timely file such Form 10-K, where such failure results from the Master
Servicer's inability or failure to obtain or receive, on a timely basis, any
information from any other party hereto, any Servicer, any Special Servicer (if
applicable) or the Custodian needed to prepare, arrange for execution or file
such Form 10-K, not resulting from its own negligence, bad faith or willful
misconduct.

      (c) Within four (4) Business Days after the occurrence of an event
requiring disclosure on Form 8-K (each such event, a "Reportable Event"), and if
directed by the Depositor, the Master Servicer shall prepare, an authorized
officer of the Master Servicer shall sign, and the Master Servicer shall file
with the Commission, on behalf of the Trust, any Form 8-K, as required by the
Exchange Act, provided that the Depositor shall prepare and file the initial
Form 8-K in connection with the issuance of the Certificates. Any disclosure or
information related to a Reportable Event or that is otherwise required to be
included on Form 8-K ("Form 8-K Disclosure Information") shall, pursuant to the
paragraph immediately below, be reported by the parties set forth on Exhibit U
and directed and approved by the Depositor, and the Master Servicer will have no
duty or liability for any failure hereunder to determine or prepare any Form 8-K
Disclosure Information (other than with respect to itself) absent such
reporting, direction and approval. If a Form 8-K cannot be filed on time or if a
previously filed Form 8-K needs to be amended, the Master Servicer will follow
the procedures set forth in Section 3.12(d). Promptly (but no later than 1
Business Day) after filing with the Commission, the Master Servicer will, make
available on its internet website a final executed copy of each Form 8-K.

      For so long as the Trust is subject to the Exchange Act reporting
requirements, no later than the end of business on the second Business Day after
the occurrence of a Reportable Event (i) the parties identified on Exhibit U
shall provide to the Master Servicer and the Depositor, to the extent known by a
Responsible Officer, in EDGAR-compatible form, or in such other form as
otherwise agreed upon by the Master Servicer and such party, the form and
substance of any Form 8-K Disclosure Information, if applicable, and (ii) the
parties identified on Exhibit U shall include with such Additional Form 8-K
Disclosure, an Additional Disclosure Notification in the form attached hereto as
Exhibit V and the Depositor will approve, as to form and substance, or
disapprove, as the case may be, the inclusion of the Form 8-K Disclosure
Information on Form 8-K. The Master Servicer has no duty under this Agreement to
monitor or enforce the performance by the parties listed on Exhibit U of their
duties under this paragraph or proactively solicit or procure from such parties
any Form 8-K Disclosure Information; except that the Master Servicer shall
enforce the obligations of the Servicers under the Servicing Agreements. The
Depositor will be responsible for any reasonable fees and expenses assessed or
incurred by the Master Servicer in connection with including any Form 8-K
Disclosure Information on Form 8-K pursuant to this paragraph.

      After preparing the Form 8-K, the Master Servicer shall forward
electronically a draft copy of the Form 8-K to the Depositor for review. Each
party to this Agreement acknowledges that the performance by the Master Servicer
of its duties under this Section 3.12(c) relating to the timely preparation and
filing of Form 8-K is contingent upon such party strictly observing all
applicable timeframes in the performance of its duties under this Section
3.12(c). The Master Servicer shall have no liability for any loss, expense,
damage, claim arising out of or with respect to any failure to properly prepare
and/or timely file such Form 8-K, where such failure results from the Master
Servicer's inability or failure to obtain or receive, on a timely basis, any
information from any other party hereto, any Servicer, the Custodian or any
Special Servicer (if applicable) needed to prepare, arrange for execution or
file such Form 8-K, not resulting from its own negligence, bad faith or willful
misconduct.

      (d) In the event that the Master Servicer is unable to timely file with
the Commission all or any required portion of any Form 8-K, 10-D or 10-K
required to be filed by this Agreement because required disclosure information
was either not delivered to it or delivered to it after the delivery deadlines
set forth in this Agreement or for any other reason, the Master Servicer will
promptly notify the Depositor and, in the case of Form 10-D or 10-K, the Master
Servicer will prepare, sign and file a Form 12b-25 pursuant to Rule 12b-25 of
the Exchange Act not later than the Business Day following the due date of the
applicable report. Within five days following the due date of any Form 10-D as
to which it has filed a Form 12b-25, the Master Servicer shall prepare, sign and
file the related Form 10-D. Within 15 days following the due date of any Form
10-K as to which it has filed a Form 12b-25, the Master Servicer shall prepare,
sign and file the related Form 10-K. In the case of Form 8-K, the Master
Servicer will, upon receipt of all required Form 8-K Disclosure Information and
at the direction of the Depositor, include such disclosure information on the
next Form 10-D. In the event that any previously filed Form 8-K, 10-D or 10-K
needs to be amended, the Master Servicer will notify the Depositor and each
party whose cooperation is required in connection with the preparation of such
amendment; provided however that such notice shall not be required in connection
with an amendment to Form 10-D due to a revision made to any Distribution Date
Statement. The parties to this Agreement acknowledge that the performance by the
Master Servicer of its duties under this Section 3.12(d) related to the timely
preparation and filing of a Form 12b-25 or any amendment to Form 8-K, 10-D or
10-K is contingent upon each such party performing its duties under this
Section. The Master Servicer shall have no liability for any loss, expense,
damage, claim arising out of or with respect to any failure to properly prepare
and/or timely file any such Form 12b-25 or any amendments to Forms 8-K, 10-D or
10-K, where such failure results from the Master Servicer's inability or failure
to obtain or receive, on a timely basis, any information from any other party
hereto, any Servicer, the Custodian or any Special Servicer (if applicable)
needed to prepare, arrange for execution or file such Form 12b-25 or any
amendments to Forms 8-K, 10-D or 10-K, not resulting from its own negligence,
bad faith or willful misconduct.

      (e) On or prior to January 30 of the first year in which the Master
Servicer is able to do so under applicable law, the Master Servicer shall
prepare, an authorized officer of the Master Servicer shall sign, and the Master
Servicer shall file with the Commission, on behalf of the Trust, a Form 15
relating to the automatic suspension of reporting in respect of the Trust under
the Exchange Act. At the beginning of any year after the filing of a Form 15, if
the number of Certificateholders of record exceeds the number set forth in
Section 15(d) of the Exchange Act or the regulations promulgated pursuant
thereto which would cause the Trust to again become subject to the reporting
requirements of the Exchange Act, the Master Servicer shall recommence preparing
and filing reports on Form 10-D, 10-K and 8-K as required pursuant to this
Section and the parties hereto, the Servicers, the Trustee, the Custodian and
any Special Servicer (if applicable) will again have the obligations set forth
in paragraphs (a) through (d) of this Section.

      (f) To the extent the Master Servicer is obligated to give any notice to
the Depositor pursuant to this Section 3.12, such notice may, notwithstanding
the provisions of Section 10.05 in this Agreement, be delivered via facsimile to
301-816-8152 or via electronic mail to
Structuredfinance-frederick@wellsfargo.com.


                                   ARTICLE IV

                    DISTRIBUTIONS IN RESPECT OF CERTIFICATES;
                         PAYMENTS TO CERTIFICATEHOLDERS;
                             STATEMENTS AND REPORTS

      Section 4.01 Distributions.

      (a) (i) On each Distribution Date, the Group I Pool Distribution Amount
and the Group II Pool Distribution Amount will be applied in the following
amounts to Group I and Group II, respectively, to the extent the Group I Pool
Distribution Amount and the Group II Pool Distribution Amount are sufficient
therefor, in the manner and in the order of priority as follows:

      first, (A) to the Classes of Group I-A Certificates, pro rata, based upon
their respective Interest Accrual Amounts, in an aggregate amount up to the
Group I-A Interest Accrual Amount with respect to such Distribution Date;
provided that prior to the applicable Accretion Termination Date, an amount
equal to the amount that would otherwise be distributable in respect of interest
to the Classes of Accrual Certificates pursuant to this provision will instead
be distributed in reduction of the Principal Balances of certain Classes of
Group I-A Certificates, in accordance with Section 4.01(b) or (B) to the Classes
of Group II-A Certificates, pro rata, based upon their respective Interest
Accrual Amounts, in an aggregate amount up to the Group II-A Interest Accrual
Amount with respect to such Distribution Date;

      second, (A) to the Classes of Group I-A Certificates, pro rata, based upon
their respective Class A Unpaid Interest Shortfalls, in an aggregate amount up
to the Aggregate Group I-A Unpaid Interest Shortfall; provided that prior to the
Accretion Termination Date, an amount equal to the amount that would otherwise
be distributable in respect of unpaid interest shortfalls to the Classes of
Accrual Certificates pursuant to this provision will instead be distributed in
reduction of the Principal Balances of certain Classes of Group I-A
Certificates, in accordance with Section 4.01(b) or (B) to the Classes of Group
II-A Certificates, pro rata, based upon their respective Class A Unpaid Interest
Shortfalls, in an aggregate amount up to the Aggregate Group II-A Unpaid
Interest Shortfall;

      third, (A) concurrently, to the Group I-A Certificates (other than the
Class I-A-PO Certificates) and the Class I-A-PO Certificates, pro rata, based on
their respective Group I-A Non-PO Optimal Principal Amount and Class I-A-PO
Optimal Principal Amount, (1) to the Classes of Group I-A Certificates (other
than the Class I-A-PO Certificates), in an aggregate amount up to the Group I-A
Non-PO Optimal Principal Amount, such distribution to be allocated among such
Classes in accordance with Section 4.01(b)(i) or Section 4.01(c), as applicable,
and (2) to the Class I-A-PO Certificates in an amount up to the Class I-A-PO
Optimal Principal Amount; or (B) concurrently, to the Group II-A Certificates
(other than the Class II-A-PO Certificates) and the Class II-A-PO Certificates,
pro rata, based on their respective Group II-A Non-PO Optimal Principal Amount
and Class II-A-PO Optimal Principal Amount, (1) to the Classes of Group II-A
Certificates (other than the Class II-A-PO Certificates), in an aggregate amount
up to the Group II-A Non-PO Optimal Principal Amount, such distribution to be
allocated among such Classes in accordance with Section 4.01(b)(ii) or Section
4.01(c), as applicable, and (2) to the Class II-A-PO Certificates in an amount
up to the Class II-A-PO Optimal Principal Amount;

      fourth, (A) to the Class I-A-PO Certificates in an amount up to the Class
I-A-PO Deferred Amount from amounts otherwise distributable (without regard to
this Paragraph fourth clause (A)) first to the Class I-B-6 Certificates pursuant
to Paragraph twenty-second clause (A) below, second to the Class I-B-5
Certificates pursuant to Paragraph nineteenth clause (A) below, third to the
Class I-B-4 Certificates pursuant to Paragraph sixteenth clause (A) below,
fourth to the Class I-B-3 Certificates pursuant to Paragraph thirteenth clause
(A) below, fifth to the Class I-B-2 Certificates pursuant to Paragraph tenth
clause (A) below, and sixth to the Class I-B-1 Certificates pursuant to
Paragraph seventh clause (A) below or (B) to the Class II-A-PO Certificates in
an amount up to the Class II-A-PO Deferred Amount from amounts otherwise
distributable (without regard to this Paragraph fourth clause (B)) first to the
Class II-B-6 Certificates pursuant to Paragraph twenty-second clause (B) below,
second to the Class II-B-5 Certificates pursuant to Paragraph nineteenth clause
(B) below, third to the Class II-B-4 Certificates pursuant to Paragraph
sixteenth clause (B) below, fourth to the Class II-B-3 Certificates pursuant to
Paragraph thirteenth clause (B) below, fifth to the Class II-B-2 Certificates
pursuant to Paragraph tenth clause (B) below, and sixth to the Class II-B-1
Certificates pursuant to Paragraph seventh clause (B) below;

      fifth, (A) to the Class I-B-1 Certificates, in an amount up to the
Interest Accrual Amount for the Class I-B-1 Certificates with respect to such
Distribution Date or (B) to the Class II-B-1 Certificates, in an amount up to
the Interest Accrual Amount for the Class II-B-1 Certificates with respect to
such Distribution Date;

      sixth, (A) to the Class I-B-1 Certificates in an amount up to the Class
I-B-1 Unpaid Interest Shortfall or (B) to the Class II-B-1 Certificates in an
amount up to the Class II-B-1 Unpaid Interest Shortfall;

      seventh, (A) to the Class I-B-1 Certificates in an amount up to the Class
I-B-1 Optimal Principal Amount; provided, however, that the amount distributable
to the Class I-B-1 Certificates pursuant to this Paragraph seventh clause (A)
will be reduced by the amount, if any, that would have been distributable to the
Class I-B-1 Certificates hereunder used to pay the Class I-A-PO Deferred Amount
as provided in Paragraph fourth clause (A) above or (B) to the Class II-B-1
Certificates in an amount up to the Class II-B-1 Optimal Principal Amount;
provided, however, that the amount distributable to the Class II-B-1
Certificates pursuant to this Paragraph seventh clause (B) will be reduced by
the amount, if any, that would have been distributable to the Class II-B-1
Certificates hereunder used to pay the Class II-A-PO Deferred Amount as provided
in Paragraph fourth clause (B) above;

      eighth, (A) to the Class I-B-2 Certificates, in an amount up to the
Interest Accrual Amount for the Class I-B-2 Certificates with respect to such
Distribution Date or (B) to the Class II-B-2 Certificates, in an amount up to
the Interest Accrual Amount for the Class II-B-2 Certificates with respect to
such Distribution Date;

      ninth, (A) to the Class I-B-2 Certificates in an amount up to the Class
I-B-2 Unpaid Interest Shortfall or (B) to the Class II-B-2 Certificates in an
amount up to the Class II-B-2 Unpaid Interest Shortfall;

      tenth, (A) to the Class I-B-2 Certificates in an amount up to the Class
I-B-2 Optimal Principal Amount; provided, however, that the amount distributable
to the Class I-B-2 Certificates, pursuant to this Paragraph tenth clause (A)
will be reduced by the amount, if any, that would have been distributable to the
Class I-B-2 Certificates hereunder used to pay the Class I-A-PO Deferred Amount
as provided in Paragraph fourth clause (A) above or (B) to the Class II-B-2
Certificates in an amount up to the Class II-B-2 Optimal Principal Amount;
provided, however, that the amount distributable to the Class II-B-2
Certificates pursuant to this Paragraph tenth clause (B) will be reduced by the
amount, if any, that would have been distributable to the Class II-B-2
Certificates hereunder used to pay the Class II-A-PO Deferred Amount as provided
in Paragraph fourth clause (B) above;

      eleventh, (A) to the Class I-B-3 Certificates, in an amount up to the
Interest Accrual Amount for the Class I-B-3 Certificates with respect to such
Distribution Date or (B) to the Class II-B-3 Certificates, in an amount up to
the Interest Accrual Amount for the Class II-B-3 Certificates with respect to
such Distribution Date;

      twelfth, (A) to the Class I-B-3 Certificates in an amount up to the Class
I-B-3 Unpaid Interest Shortfall or (B) to the Class II-B-3 Certificates in an
amount up to the Class II-B-3 Unpaid Interest Shortfall;

      thirteenth, (A) to the Class I-B-3 Certificates in an amount up to the
Class I-B-3 Optimal Principal Amount; provided, however, that the amount
distributable to the Class I-B-3 Certificates pursuant to this Paragraph
thirteenth clause (A) will be reduced by the amount, if any, that would have
been distributable to the Class I-B-3 Certificates hereunder used to pay the
Class I-A-PO Deferred Amount as provided in Paragraph fourth clause (A) above or
(B) to the Class II-B-3 Certificates in an amount up to the Class II-B-3 Optimal
Principal Amount; provided, however, that the amount distributable to the Class
II-B-3 Certificates pursuant to this Paragraph thirteenth clause (B) will be
reduced by the amount, if any, that would have been distributable to the Class
II-B-3 Certificates hereunder used to pay the Class II-A-PO Deferred Amount as
provided in Paragraph fourth clause (B) above;

      fourteenth, (A) to the Class I-B-4 Certificates in an amount up to the
Interest Accrual Amount for the Class I-B-4 Certificates with respect to such
Distribution Date or (B) to the Class II-B-4 Certificates in an amount up to the
Interest Accrual Amount for the Class II-B-4 Certificates with respect to such
Distribution Date;

      fifteenth, (A) to the Class I-B-4 Certificates in an amount up to the
Class I-B-4 Unpaid Interest Shortfall or (B) to the Class II-B-4 Certificates in
an amount up to the Class II-B-4 Unpaid Interest Shortfall;

      sixteenth, (A) to the Class I-B-4 Certificates in an amount up to the
Class I-B-4 Optimal Principal Amount; provided, however, that the amount
distributable to the Class I-B-4 Certificates pursuant to this Paragraph
sixteenth clause (A) will be reduced by the amount, if any, that would have been
distributable to the Class I-B-4 Certificates hereunder used to pay the Class
I-A-PO Deferred Amount as provided in Paragraph fourth clause (A) above or (B)
to the Class II-B-4 Certificates in an amount up to the Class II-B-4 Optimal
Principal Amount; provided, however, that the amount distributable to the Class
II-B-4 Certificates pursuant to this Paragraph sixteenth clause (B) will be
reduced by the amount, if any, that would have been distributable to the Class
II-B-4 Certificates hereunder used to pay the Class II-A-PO Deferred Amount as
provided in Paragraph fourth clause (B) above;

      seventeenth, (A) to the Class I-B-5 Certificates in an amount up to the
Interest Accrual Amount for the Class I-B-5 Certificates with respect to such
Distribution Date or (B) to the Class II-B-5 Certificates in an amount up to the
Interest Accrual Amount for the Class II-B-5 Certificates with respect to such
Distribution Date;

      eighteenth, (A) to the Class I-B-5 Certificates in an amount up to the
Class I-B-5 Unpaid Interest Shortfall or (B) to the Class II-B-5 Certificates in
an amount up to the Class II-B-5 Unpaid Interest Shortfall;

      nineteenth, (A) to the Class I-B-5 Certificates in an amount up to the
Class I-B-5 Optimal Principal Amount; provided, however, that the amount
distributable to the Class I-B-5 Certificates pursuant to this Paragraph
nineteenth clause (A) will be reduced by the amount, if any, that would have
been distributable to the Class I-B-5 Certificates hereunder used to pay the
Class I-A-PO Deferred Amount as provided in Paragraph fourth clause (A) above or
(B) to the Class II-B-5 Certificates in an amount up to the Class II-B-5 Optimal
Principal Amount; provided, however, that the amount distributable to the Class
II-B-5 Certificates pursuant to this Paragraph nineteenth clause (B) will be
reduced by the amount, if any, that would have been distributable to the Class
II-B-5 Certificates hereunder used to pay the Class II-A-PO Deferred Amount as
provided in Paragraph fourth clause (B) above;

      twentieth, (A) to the Class I-B-6 Certificates in an amount up to the
Interest Accrual Amount for the Class I-B-6 Certificates with respect to such
Distribution Date or (B) to the Class II-B-6 Certificates in an amount up to the
Interest Accrual Amount for the Class II-B-6 Certificates with respect to such
Distribution Date;

      twenty-first, (A) to the Class I-B-6 Certificates in an amount up to the
Class I-B-6 Unpaid Interest Shortfall or (B) to the Class II-B-6 Certificates in
an amount up to the Class II-B-6 Unpaid Interest Shortfall;

      twenty-second, (A) to the Class I-B-6 Certificates in an amount up to the
Class I-B-6 Optimal Principal Amount; provided, however, that the amount
distributable to the Class I-B-6 Certificates pursuant to this Paragraph
twenty-second clause (A) will be reduced by the amount, if any, that would have
been distributable to the Class I-B-6 Certificates hereunder used to pay the
Class I-A-PO Deferred Amount as provided in Paragraph fourth clause (A) above or
(B) to the Class II-B-6 Certificates in an amount up to the Class II-B-6 Optimal
Principal Amount; provided, however, that the amount distributable to the Class
II-B-6 Certificates pursuant to this Paragraph twenty-second clause (B) will be
reduced by the amount, if any, that would have been distributable to the Class
II-B-6 Certificates hereunder used to pay the Class II-A-PO Deferred Amount as
provided in Paragraph fourth clause (B) above; and

      twenty-third, to the Holder of the Class I-A-R Certificate (i) in respect
of the Class I-A-R Interest, any amounts remaining in the Upper-Tier Certificate
Account and (ii) in respect of the Class I-A-LR Interest, any amounts remaining
in the Payment Account.

      (ii) Notwithstanding the foregoing, after the Principal Balance or
Notional Amount of any Class has been reduced to zero, such Class will be
entitled to no further distributions of principal or interest (including,
without limitation, any Unpaid Interest Shortfalls).

      With respect to any Distribution Date, the amount of the Principal
Adjustment, if any, attributable to any Class of Class B Certificates of a Group
will be allocated to the Classes of Class A Certificates (other than the Class
A-PO Certificates) of such Group and any Class of Class B Certificates of such
Group with a lower numerical designation pro rata based on their outstanding
Principal Balances.

      On each Distribution Date, any Reimbursement Amount shall be distributed
sequentially to the Classes of Certificates of the related Group then
outstanding which bore the loss to which such Reimbursement Amount relates
beginning with the most senior of such Class of Certificates of such Group, up
to, with respect to each Class, the amount of loss borne by such Class. Any
Reimbursement Amount remaining after the application described in the preceding
sentence shall be included in the Group I Pool Distribution Amount or Group II
Pool Distribution Amount, as applicable.

      (iii) Distributions on the Uncertificated Lower-Tier Interests. Each
Uncertificated Lower-Tier Interest shall receive distributions in respect of
principal in an amount equal to the amount of principal distributed to its
respective Corresponding Upper-Tier Class or Classes as provided herein. Each
Uncertificated Lower-Tier Interest (other than the Class I-A-LPO Interest and
Class II-A-LPO Interest) shall receive distributions in respect of interest in
an amount equal to the Interest Accrual Amounts and Unpaid Interest Shortfalls,
as the case may be, in respect of its Corresponding Upper-Tier Class or Classes,
in each case to the extent actually distributed thereon (or, in the case of a
Class of Accrual Certificates, added to its Principal Balance). Such amounts
distributed to the Uncertificated Lower-Tier Interests in respect of principal
and interest with respect to any Distribution Date are referred to herein
collectively as the "Lower-Tier Distribution Amount."

      As of any date, the principal balance of each Uncertificated Lower-Tier
Interest equals the Principal Balances of the respective Corresponding
Upper-Tier Class or Classes, or in the case of the Class I-A-L5 Interest, the
Principal Balance of the Class I-A-5 Certificates. The initial principal balance
of each Uncertificated Lower-Tier Interest equals the Original Principal
Balances of the respective Corresponding Upper-Tier Class or Classes, or in the
case of the Class I-A-L5 Interest, the Original Principal Balance of the Class
I-A-5 Certificates.

      The pass-through rate with respect to the Class II-A-L2 Interest shall be
5.500% per annum. The pass-through rate with respect to the Class I-A-L1
Interest, Class I-A-L5 Interest, Class I-A-LUR Interest, Class II-A-L3 Interest,
Class I-B-L1 Interest, Class I-B-L2 Interest, Class I-B-L3 Interest, Class
I-B-L4 Interest, Class I-B-L5 Interest, Class I-B-L6 Interest, Class II-B-L1
Interest, Class II-B-L2 Interest, Class II-B-L3 Interest, Class II-B-L4
Interest, Class II-B-L5 Interest and Class II-B-L6 Interest shall be 5.750% per
annum. The pass-through rate with respect to the Class II-A-L1 Interest shall be
6.000% per annum. The Class I-A-LPO Interest and Class II-A-LPO Interest are
principal-only interests and are not entitled to distributions of interest. Any
Non-Supported Interest Shortfalls will be allocated to each Uncertificated
Lower-Tier Interest in the same relative proportions as interest is allocated to
such Uncertificated Lower-Tier Interest.

      (b) (i) Group I-A Certificates

      I. On each Distribution Date occurring prior to the Accretion Termination
Date for the Class I-A-3 and Class I-A-4 Certificates, the applicable Accrual
Distribution Amounts will be distributed, sequentially, as follows:

      first, to the Class I-A-2 Certificates; and

      second, concurrently, to the Class I-A-3 and Class I-A-4 Certificates, pro
rata.

      II. On each Distribution Date occurring prior to the Accretion Termination
Date for the Class I-A-7 Certificates, the applicable Accrual Distribution
Amount will be distributed, sequentially, as follows:

      first, to the Class I-A-5 Certificates, up to the TAC Principal Amount for
such Distribution Date; and

      second, to the Class I-A-7 Certificates.

      III. On each Distribution Date occurring prior to the Accretion
Termination Date for the Class I-A-10 Certificates, the applicable Accrual
Distribution Amount will be distributed, sequentially, as follows:

      first, sequentially, up to $30,845 for such Distribution Date, as follows:

      (a) to the Class I-A-5 Certificates, up to the TAC Principal Amount for
such Distribution Date;

      (b) to the Class I-A-7 Certificates; and

      (c) to the Class I-A-5 Certificates;

      second, sequentially, to the Class I-A-8 and Class I-A-9 Certificates, up
to $701,030 for such Distribution Date;

      third, to the Class I-A-5 Certificates, up to the TAC Principal Amount for
such Distribution Date; and

      fourth, sequentially, to the Class I-A-7, Class I-A-5, Class I-A-8, Class
I-A-9 and Class I-A-10 Certificates.

      IV. On each Distribution Date occurring prior to the applicable
Subordination Depletion Date, the Group I-A Non-PO Principal Distribution Amount
will be allocated among and distributed in reduction of the Principal Balances
of the Group I-A Certificates (other than the Class I-A-PO Certificates),
sequentially, as follows:

      first, to the Class I-A-R Certificate;

      second, concurrently, to the Class I-A-12 and Class I-A-13 Certificates,
pro rata, up to the Priority Amount 1 for such Distribution Date;

      third, concurrently, as follows:

      (a) 69.3009071398%, sequentially, as follows:

            (i) to the Class I-A-1 Certificates; and

            (ii) concurrently, as follows:

             (A) 73.4149681785%, sequentially, as follows:

                (1) to the Class I-A-2 Certificates; and

                (2) concurrently, to the Class I-A-3 and Class I-A-4
Certificates, pro rata; and

             (B) 26.5850318215% to the Class I-A-14 Certificates; and

      (b) 30.6990928602%, sequentially, as follows:

      (i) to the Class I-A-11 Certificates, up to the Priority Amount 2 for such
Distribution Date;

      (ii) sequentially, up to an amount that, when combined with the amount
distributed pursuant to priority first of the allocation of the Accrual
Distribution Amount for the Class I-A-10 Certificates, does not exceed $30,845
for such Distribution Date, as follows:

      (A) to the Class I-A-5 Certificates, up to the TAC Principal Amount for
such Distribution Date;

      (B) to the Class I-A-7 Certificates; and

      (C) to the Class I-A-5 Certificates;

      (iii) sequentially, to the Class I-A-8 and Class I-A-9 Certificates, up to
an amount that, when combined with the amount distributed pursuant to priority
second of the allocation of the Accrual Distribution Amount for the Class I-A-10
Certificates, does not exceed $701,030 for such Distribution Date;

      (iv) to the Class I-A-5 Certificates, up to the TAC Principal Amount for
such Distribution Date; and

      (v) sequentially, to the Class I-A-7, Class I-A-5, Class I-A-8, Class
I-A-9, Class I-A-10 and Class I-A-11 Certificates; and

      fourth, concurrently, to the Class I-A-12 and Class I-A-13 Certificates,
pro rata.

      (ii) Group II-A Certificates

      On each Distribution Date occurring prior to the applicable Subordination
Depletion Date, the Group II-A Non-PO Principal Distribution Amount will be
allocated among and distributed in reduction of the Principal Balances of the
Group II-A Certificates (other than the Class II-A-PO Certificates),
concurrently, to the Class II-A-1, Class II-A-2 and Class II-A-3 Certificates,
pro rata.

            As used above, the "TAC Principal Amount" for any Distribution Date
means the amount, if any, that would reduce the Principal Balance of the TAC
Certificates to the percentage of the initial Principal Balance of the TAC
Certificates shown in the table appearing in Schedule II with respect to such
Distribution Date.

      (c) Notwithstanding the foregoing, on each Distribution Date occurring on
or subsequent to the applicable Subordination Depletion Date, (x) the Group I-A
Non-PO Principal Distribution Amount shall be distributed among the Classes of
Group I-A Certificates (other than the Class I-A-PO Certificates), and (y) the
Group II-A Non-PO Principal Distribution Amount shall be distributed among the
Classes of Group II-A Certificates (other than the Class II-A-PO Certificates)
pro rata in accordance with their outstanding Principal Balances without regard
to either the proportions or the priorities set forth in Sections 4.01(b)(i) and
(ii).

      (d) (i) For purposes of determining whether the Classes of Class B
Certificates of a Group are eligible to receive distributions of principal with
respect to any Distribution Date, the following tests shall apply:

            (A) (i) if the Current Class I-B-1 Fractional Interest is less than
      the Original Class I-B-1 Fractional Interest and the Class I-B-1 Principal
      Balance is greater than zero, the Class I-B-2, Class I-B-3, Class I-B-4,
      Class I-B-5 and Class I-B-6 Certificates shall not be eligible to receive
      distributions of principal; or

            (ii) if the Current Class II-B-1 Fractional Interest is less than
      the Original Class II-B-1 Fractional Interest and the Class II-B-1
      Principal Balance is greater than zero, the Class II-B-2, Class II-B-3,
      Class II-B-4, Class II-B-5 and Class II-B-6 Certificates shall not be
      eligible to receive distributions of principal; or

            (B) (i) if the Current Class I-B-2 Fractional Interest is less than
      the Original Class I-B-2 Fractional Interest and the Class I-B-2 Principal
      Balance is greater than zero, the Class I-B-3, Class I-B-4, Class I-B-5
      and Class I-B-6 Certificates shall not be eligible to receive
      distributions of principal; or

            (ii) if the Current Class II-B-2 Fractional Interest is less than
      the Original Class II-B-2 Fractional Interest and the Class II-B-2
      Principal Balance is greater than zero, the Class II-B-3, Class II-B-4,
      Class II-B-5 and Class II-B-6 Certificates shall not be eligible to
      receive distributions of principal; or

            (C) (i) if the Current Class I-B-3 Fractional Interest is less than
      the Original Class I-B-3 Fractional Interest and the Class I-B-3 Principal
      Balance is greater than zero, the Class I-B-4, Class I-B-5 and Class I-B-6
      Certificates shall not be eligible to receive distributions of principal;
      or

            (ii) if the Current Class II-B-3 Fractional Interest is less than
      the Original Class II-B-3 Fractional Interest and the Class II-B-3
      Principal Balance is greater than zero, the Class II-B-4, Class II-B-5 and
      Class II-B-6 Certificates shall not be eligible to receive distributions
      of principal; or

            (D) (i) if the Current Class I-B-4 Fractional Interest is less than
      the Original Class I-B-4 Fractional Interest and the Class I-B-4 Principal
      Balance is greater than zero, the Class I-B-5 and Class I-B-6 Certificates
      shall not be eligible to receive distributions of principal; or

            (ii) if the Current Class II-B-4 Fractional Interest is less than
      the Original Class II-B-4 Fractional Interest and the Class II-B-4
      Principal Balance is greater than zero, the Class II-B-5 and Class II-B-6
      Certificates shall not be eligible to receive distributions of principal;
      or

            (E) (i) if the Current Class I-B-5 Fractional Interest is less than
      the Original Class I-B-5 Fractional Interest and the Class I-B-5 Principal
      Balance is greater than zero, the Class I-B-6 Certificates shall not be
      eligible to receive distributions of principal; or

            (ii) if the Current Class II-B-5 Fractional Interest is less than
      the Original Class II-B-5 Fractional Interest and the Class II-B-5
      Principal Balance is greater than zero, the Class II-B-6 Certificates
      shall not be eligible to receive distributions of principal.

      (ii) Notwithstanding the foregoing, if on any Distribution Date the
aggregate distributions to Holders of the Classes of Class B Certificates of a
Group entitled to receive distributions of principal would reduce the Principal
Balances of the Classes of Class B Certificates of such Group entitled to
receive distributions of principal below zero, first the Group I Class B
Prepayment Percentage or the Group II Class B Prepayment Percentage, as the case
may be, of any affected Class of Class B Certificates for such Distribution Date
beginning with the affected Class of such Group with the lowest numerical Class
designation and then, if necessary, the Group I Class B Percentage or Group II
Class B Percentage, as the case may be, of such Class of the Class B
Certificates for such Distribution Date shall be reduced to the respective
percentages necessary to bring the Principal Balance of such Class of Class B
Certificates to zero. The Group I Class B Prepayment Percentages or the Group II
Class B Prepayment Percentages, as the case may be, and the Group I Class B
Percentages or the Group II Class B Percentages, as the case may be, of the
remaining Classes of Class B Certificates in the related Group will be
recomputed substituting for the Group I Subordinated Prepayment Percentage or
Group II Subordinated Prepayment Percentage, as the case may be, and Group I
Subordinated Percentage or Group II Subordinated Percentage, as the case may be,
in such computations the difference between (A) the Group I Subordinated
Prepayment Percentage or Group II Subordinated Prepayment Percentage, as the
case may be, or Group I Subordinated Percentage or Group II Subordinated
Percentage, as the case may be, and (B) the percentages determined in accordance
with the preceding sentence necessary to bring the Principal Balances of the
affected Classes of Class B Certificates of such Group to zero; provided,
however, that if the Principal Balances of all the Classes of Class B
Certificates in the related Group eligible to receive distributions of principal
shall be reduced to zero on such Distribution Date, the Group I Class B
Prepayment Percentage or Group II Class B Prepayment Percentage, as the case may
be, and Group I Class B Percentage or Group II Class B Percentage, as the case
may be, of the Class of Class B Certificates in such Group with the lowest
numerical Class designation which would otherwise be ineligible to receive
distributions of principal in accordance with this Section shall equal the
remainder of the Group I Subordinated Prepayment Percentage or Group II
Subordinated Prepayment Percentage, as applicable, for such Distribution Date
minus the sum of the Group I Class B Prepayment Percentages or Group II Class B
Prepayment Percentages of the Classes of Class B Certificates in such Group
having lower numerical Class designations, if any, and the remainder of the
Group I Subordinated Percentage or Group II Subordinated Percentage, as the case
may be, for such Distribution Date minus the sum of the Group I Class B
Percentages or Group II Class B Percentages, as applicable of the Classes of
Class B Certificates in such Group having lower numerical Class designations, if
any, respectively. Any entitlement of any Class of Class B Certificates to
principal payments solely pursuant to this clause (ii) shall not cause such
Class to be regarded as being eligible to receive principal distributions for
the purpose of applying the definition of its Group I Class B Percentage or
Group II Class B Percentage, as applicable or Group I Class B Prepayment
Percentage or Group II Class B Prepayment Percentage, as applicable.

      (e) The Master Servicer shall establish and maintain the Upper-Tier
Certificate Account, which shall be a separate trust account and an Eligible
Account (provided that such account may be deemed a sub-account of the Payment
Account so long as the Master Servicer is the Paying Agent). On each
Distribution Date other than the Final Distribution Date (if such Final
Distribution Date is in connection with a purchase of the assets of the Trust
Estate by the Depositor), the Paying Agent shall, on behalf of the Master
Servicer, from funds available on deposit in the Payment Account, be deemed to
deposit, in immediately available funds, by wire transfer or otherwise, into the
Upper-Tier Certificate Account the Lower-Tier Distribution Amount. The Master
Servicer may clear and terminate the Upper-Tier Certificate Account pursuant to
Section 9.01.

      (f) On each Distribution Date other than the Final Distribution Date (if
such Final Distribution Date is in connection with a purchase of the assets of
the Trust Estate by the Depositor), the Paying Agent shall, from funds remitted
to it by the Master Servicer, distribute to each Certificateholder of record on
the preceding Record Date (other than as provided in Section 9.01 respecting the
final distribution to Certificateholders or in the last paragraph of this
Section 4.01(f) respecting the final distribution in respect of any Class)
either in immediately available funds by wire transfer to the account of such
Certificateholder at a bank or other entity having appropriate facilities
therefor, if such Certificateholder holds Certificates having a Denomination at
least equal to that specified in Section 11.25, and has so notified the Paying
Agent at least seven Business Days prior to the Distribution Date or, if such
Holder holds Certificates having, in the aggregate, a Denomination less than the
requisite minimum Denomination or if such Holder holds the Class I-A-R
Certificate or has not so notified the Paying Agent, by check mailed to such
Holder at the address of such Holder appearing in the Certificate Register, such
Holder's share of the Group I-A Distribution Amount or Group II-A Distribution
Amount, as applicable, with respect to each Class of Class A Certificates and
the Class B Distribution Amount with respect to each Class of Class B
Certificates.

      In the event that, on any Distribution Date prior to the Final
Distribution Date, the Principal Balance of any Class of Class A Certificates
(other than the Class I-A-6 or Class I-A-R Certificates) or the Principal
Balance of any Class of Class B Certificates would be reduced to zero, or in the
case of the Class I-A-6 Certificates, the Class I-A-6 Notional Amount, would be
reduced to zero, the Master Servicer shall, as soon as practicable after the
Determination Date relating to such Distribution Date, send notice to the Paying
Agent. The Paying Agent shall then send a notice to each Certificateholder of
such Class with a copy to the Certificate Registrar, specifying that the final
distribution with respect to such Class will be made on such Distribution Date
only upon the presentation and surrender of such Certificateholder's
Certificates at the office or agency of the Certificate Registrar therein
specified; provided, however, that the failure to give such notice will not
entitle a Certificateholder to any interest beyond the interest payable with
respect to such Distribution Date in accordance with Section 4.01(a)(i).

      (g) The Paying Agent shall withhold or cause to be withheld such amounts
as may be required by the Code (giving full effect to any exemptions from
withholding and related certifications required to be furnished by
Certificateholders and any reductions to withholding by virtue of any bilateral
tax treaties and any applicable certification required to be furnished by
Certificateholders with respect thereto) from distributions to be made to
Persons other than U.S. Persons ("Non-U.S. Persons"). Amounts withheld pursuant
to this Section 4.01(g) shall be treated as having been distributed to the
related Certificateholder for all purposes of this Agreement. For the purposes
of this paragraph, a "U.S. Person" is a citizen or resident of the United
States, a corporation or partnership (unless, in the case of a partnership,
Treasury regulations are adopted that provide otherwise) created or organized in
or under the laws of the United States, any state thereof or the District of
Columbia, including an entity treated as a corporation or partnership for
federal income tax purposes, an estate whose income is subject to United States
federal income tax regardless of its source, or a trust if a court within the
United States is able to exercise primary supervision over the administration of
such trust, and one or more such U.S. Persons have the authority to control all
substantial decisions of such trust (or, to the extent provided in applicable
Treasury regulations, certain trusts in existence on August 20, 1996 which are
eligible to elect to be treated as U.S. Persons).

      Section 4.02 Allocation of Realized Losses.

      (a) With respect to any Distribution Date, the principal portion of
Realized Losses on the Group I Mortgage Loans (other than Debt Service
Reductions) occurring with respect to Group I Mortgage Loans will be allocated
as follows:

      first, concurrently, to the Class I-A-PO Certificates and Class I-B-6
Certificates, pro rata, based on the applicable PO Fraction and the applicable
Non-PO Fraction of such Mortgage Loans, respectively, until the Class I-B-6
Principal Balance has been reduced to zero;

      second, concurrently, to the Class I-A-PO Certificates and Class I-B-5
Certificates, pro rata, based on the applicable PO Fraction and the applicable
Non-PO Fraction of such Mortgage Loans, respectively, until the Class I-B-5
Principal Balance has been reduced to zero;

      third, concurrently, to the Class I-A-PO Certificates and Class I-B-4
Certificates, pro rata, based on the applicable PO Fraction and the applicable
Non-PO Fraction of such Mortgage Loans, respectively, until the Class I-B-4
Principal Balance has been reduced to zero;

      fourth, concurrently, to the Class I-A-PO Certificates and Class I-B-3
Certificates, pro rata, based on the applicable PO Fraction and the applicable
Non-PO Fraction of such Mortgage Loans, respectively, until the Class I-B-3
Principal Balance has been reduced to zero;

      fifth, concurrently, to the Class I-A-PO Certificates and Class I-B-2
Certificates, pro rata, based on the applicable PO Fraction and the applicable
Non-PO Fraction of such Mortgage Loans, respectively, until the Class I-B-2
Principal Balance has been reduced to zero;

      sixth, concurrently, to the Class I-A-PO Certificates and Class I-B-1
Certificates, pro rata, based on the applicable PO Fraction and the applicable
Non-PO Fraction of such Mortgage Loans, respectively, until the Class I-B-1
Principal Balance has been reduced to zero; and

      seventh, concurrently, to the Group I-A Certificates (other than the Class
I-A-PO Certificates) and Class I-A-PO Certificates, pro rata, based on the
applicable Non-PO Fraction and the applicable PO Fraction of such Mortgage
Loans, respectively.

      With respect to any Distribution Date, the principal portion of Realized
Losses on the Group II Mortgage Loans (other than Debt Service Reductions)
occurring with respect to Group II Mortgage Loans will be allocated as follows:

      first, concurrently, to the Class II-A-PO Certificates and Class II-B-6
Certificates, pro rata, based on the applicable PO Fraction and the applicable
Non-PO Fraction of such Mortgage Loans, respectively, until the Class II-B-6
Principal Balance has been reduced to zero;

      second, concurrently, to the Class II-A-PO Certificates and Class II-B-5
Certificates, pro rata, based on the applicable PO Fraction and the applicable
Non-PO Fraction of such Mortgage Loans, respectively, until the Class II-B-5
Principal Balance has been reduced to zero;

      third, concurrently, to the Class II-A-PO Certificates and Class II-B-4
Certificates, pro rata, based on the applicable PO Fraction and the applicable
Non-PO Fraction of such Mortgage Loans, respectively, until the Class II-B-4
Principal Balance has been reduced to zero;

      fourth, concurrently, to the Class II-A-PO Certificates and Class II-B-3
Certificates, pro rata, based on the applicable PO Fraction and the applicable
Non-PO Fraction of such Mortgage Loans, respectively, until the Class II-B-3
Principal Balance has been reduced to zero;

      fifth, concurrently, to the Class II-A-PO Certificates and Class II-B-2
Certificates, pro rata, based on the applicable PO Fraction and the applicable
Non-PO Fraction of such Mortgage Loans, respectively, until the Class II-B-2
Principal Balance has been reduced to zero;

      sixth, concurrently, to the Class II-A-PO Certificates and Class II-B-1
Certificates, pro rata, based on the applicable PO Fraction and the applicable
Non-PO Fraction of such Mortgage Loans, respectively, until the Class II-B-1
Principal Balance has been reduced to zero; and

      seventh, concurrently, to the Group II-A Certificates (other than the
Class II-A-PO Certificates) and Class II-A-PO Certificates, pro rata, based on
the applicable Non-PO Fraction and the applicable PO Fraction of such Mortgage
Loans, respectively.

      This allocation of Realized Losses will be effected through the reduction
of the applicable Class's Principal Balance through the operation of the
definition of Principal Balance and the provisos in the definitions of Class
I-B-1 Principal Balance, Class I-B-2 Principal Balance, Class I-B-3 Principal
Balance, Class I-B-4 Principal Balance, Class I-B-5 Principal Balance, Class
I-B-6 Principal Balance, Class II-B-1 Principal Balance, Class II-B-2 Principal
Balance, Class II-B-3 Principal Balance, Class II-B-4 Principal Balance, Class
II-B-5 Principal Balance and Class II-B-6 Principal Balance.

      (b) Any Realized Losses allocated to a Class of Class A Certificates or
Class B Certificates pursuant to Section 4.02(a) shall be allocated among the
Certificates of such Class based on their Percentage Interests.

      (c) After the Group I-B Principal Balance or Group II-B Principal Balance
has been reduced to zero, the interest portion of Realized Losses occurring with
respect to any Group I Mortgage Loan or Group II Mortgage Loan, as applicable,
will be allocated among the outstanding Classes of Group I-A Certificates and
Group II-A Certificates, respectively, based upon their Group I-A and Group II-A
Interest Percentages.

      (d) Realized Losses allocated in accordance with this Section 4.02 will be
allocated as follows: (i) Liquidated Loan Losses on Liquidated Loans for which
the Liquidation Proceeds were received during, and Bankruptcy Losses incurred in
a period corresponding to, an Unscheduled Principal Receipt Period for Full
Unscheduled Principal Receipts that is a Mid-Month Receipt Period will be
allocated on the Determination Date in the month following the month in which
such Mid-Month Receipt Period ended and (ii) Liquidated Loan Losses on
Liquidated Loans for which the Liquidation Proceeds were received during, and
Bankruptcy Losses incurred in a period corresponding to, an Unscheduled
Principal Receipt Period for Full Unscheduled Principal Receipts that is a Prior
Month Receipt Period will be allocated on the Determination Date in the second
month following the month which is such Prior Month Receipt Period.

      (e) With respect to any Distribution Date, the principal portion of
Realized Losses and recoveries attributable to previously allocated Realized
Losses allocated pursuant to this Section 4.02 will be allocated to each
Uncertificated Lower-Tier Interest in an amount equal to the amount allocated to
its respective Corresponding Upper-Tier Class or Classes as provided above.

      (f) With respect to any Distribution Date, the interest portion of
Realized Losses allocated pursuant to this Section 4.02 will be allocated to
each Uncertificated Lower-Tier Interest in the same relative proportions as
interest is allocated to such Uncertificated Lower-Tier Interest.

      Section 4.03 Paying Agent.

      (a) The Paying Agent shall establish and maintain a Payment Account, which
shall be a separate trust account (unless the Master Servicer is the Paying
Agent, in which case, the Certificate Account may be the Payment Account) and an
Eligible Account, in which the Master Servicer shall cause to be deposited from
funds in the Certificate Account or, to the extent required hereunder, from its
own funds (i) at or before 10:00 a.m., New York time, on the Business Day
preceding each Distribution Date, by wire transfer of immediately available
funds, any Periodic Advance for such Distribution Date, pursuant to Section 3.03
and (ii) at or before 10:00 a.m., New York time, on the Business Day preceding
each Distribution Date, by wire transfer of immediately available funds, an
amount equal to the Pool Distribution Amount. The Master Servicer may cause the
Paying Agent to invest the funds in the Payment Account. Any such investment
shall be in Eligible Investments, which shall mature not later than the Business
Day preceding the related Distribution Date (unless the Eligible Investments are
obligations of the institution that maintains such account, in which case such
Eligible Investments shall mature not later than the Distribution Date), and
shall not be sold or disposed of prior to maturity. All income and gain realized
from any such investment shall be for the benefit of the Master Servicer and
shall be subject to its withdrawal or order from time to time. The amount of any
losses incurred in respect of any such investments shall be deposited in the
Payment Account by the Master Servicer out of its own funds immediately as
realized. The Paying Agent may withdraw from the Payment Account any amount
deposited in the Payment Account that was not required to be deposited therein
and may clear and terminate the Payment Account pursuant to Section 9.01.

      (b) Wells Fargo Bank is hereby appointed as initial Paying Agent to make
distributions to Certificateholders and to make available to Certificateholders
the Distribution Date Statements and the annual statements required by Section
4.04. The Trustee may, at any time, remove or replace the Paying Agent, other
than Wells Fargo Bank for so long as Wells Fargo Bank is acting as the Master
Servicer. If Wells Fargo Bank is no longer acting as Master Servicer, the Master
Servicer shall pay, from its own funds, the reasonable compensation of any
Paying Agent other than Wells Fargo Bank.

      The Trustee shall cause any Paying Agent that is not U.S. Bank National
Association or Wells Fargo Bank to execute and deliver to the Trustee an
instrument (a "Paying Agent Agreement") in which such Paying Agent agrees with
the Trustee that such Paying Agent shall:

            (i) hold all amounts remitted to it by the Master Servicer for
      distribution to Certificateholders in trust for the benefit of
      Certificateholders until such amounts are distributed to
      Certificateholders or otherwise disposed of as herein provided;

            (ii) give the Trustee notice of any default by the Master Servicer
      in remitting any required amount;

            (iii) at any time during the continuance of any such default, upon
      the written request of the Trustee, forthwith pay to the Trustee all
      amounts held in trust by such Paying Agent; and

            (iv) provide to the Master Servicer the assessment of compliance and
      accountants report provided for in Section 3.11 with respect to the
      Servicing Criteria set forth in Item 1122(d) of Regulation AB applicable
      to the duties of the Paying Agent.

      Section 4.04 Statements to Certificateholders; Reports to the Trustee and
the Depositor.

      (a) On each Distribution Date, the Master Servicer shall make available in
accordance with subsection (b) of this Section 4.04 to each Holder of a
Certificate, the Trustee, the Paying Agent and the Depositor a statement (the
"Distribution Date Statement") setting forth:

            (i) the applicable Determination Date, the applicable Record Date
      and the actual Distribution Date;

            (ii) the amount of such distribution to Holders of each Class of
      Class A Certificates allocable to principal, separately identifying the
      aggregate amount of any Unscheduled Principal Receipts and Liquidation
      Proceeds included therein and the Principal Balance of each Class of Class
      A Certificates;

            (iii) (A) the amount of such distribution to Holders of each Class
      of Class A Certificates allocable to interest, (B) the amount of the
      Current Group I-A Interest Distribution Amount allocated to each Class of
      Group I-A Certificates and Current Group II-A Interest Distribution Amount
      allocated to each Class of Group II-A Certificates, (C) any Group I
      Interest Shortfall Amounts or Group II Interest Shortfall Amounts arising
      with respect to such Distribution Date and any remaining Class A Unpaid
      Interest Shortfall with respect to each Class after giving effect to such
      distribution, (D) the amount of any Non-Supported Interest Shortfall
      allocated to each Class of Class A Certificates for such Distribution Date
      and (E) the amount of any Relief Act Shortfall allocated to each Class of
      Class A Certificates for such Distribution Date;

            (iv) the amount of such distribution to Holders of each Class of
      Class B Certificates allocable to principal, separately identifying the
      aggregate amount of any Unscheduled Principal Receipts and Liquidation
      Proceeds included therein and the Principal Balance of each Class of Class
      B Certificates;

            (v) (A) the amount of such distribution to Holders of each Class of
      Class B Certificates allocable to interest, (B) the amount of the Current
      Class B Interest Distribution Amount for a Group allocated to each Class
      of Class B Certificates of such Group, (C) any Class B Interest Shortfall
      Amounts arising with respect to such Distribution Date and any remaining
      Class B Unpaid Interest Shortfall with respect to each Class of Class B
      Certificates of a Group after giving effect to such distribution, (D) the
      amount of any Non-Supported Interest Shortfall for a Group allocated to
      each Class of Class B Certificates of such Group for such Distribution
      Date and (E) the amount of any Relief Act Shortfalls allocated to each
      Class of Class B Certificates of such Group for such Distribution Date;
      (vi) the amount of any Periodic Advance by or reimbursed to any Servicer,
      the Master Servicer or the Trustee pursuant to the Servicing Agreements or
      this Agreement;

            (vi) the number and aggregate principal balance of Group I Mortgage
      Loans and Group II Mortgage Loans outstanding, the weighted average
      Mortgage Interest Rate and weighted average remaining term to maturity of
      the Mortgage Loans outstanding and the cumulative prepayment amounts, in
      each case, as of the preceding Determination Date;

            (vii) the number and aggregate principal balances of the of Group I
      Mortgage Loans and Group II Mortgage Loans by range of current Mortgage
      Interest Rates;

            (viii) the pools factors for such Distribution Date;

            (ix) the beginning and ending balance of the Certificate Account;

            (x) the Group I-A Principal Balance, the Group II-A Principal
      Balance, the Principal Balance of each Class of Class A Certificates, the
      Group I-B Principal Balance, the Group II-B Principal Balance and the
      Principal Balance of each Class of Class B Certificates prior to and after
      giving effect to the distributions of principal made, and the principal
      portion of Realized Losses, if any, allocated with respect to such
      Distribution Date;

            (xi) the Group I Adjusted Pool Amount, the Group II Adjusted Pool
      Amount, the Group I Adjusted Pool Amount (Non-PO Portion), the Group II
      Adjusted Pool Amount (Non-PO Portion), the Group I Adjusted Pool Amount
      (PO Portion), the Group II Adjusted Pool Amount (PO Portion), the Group I
      Pool Scheduled Principal Balance of the Group I Mortgage Loans for such
      Distribution Date, the Group II Pool Scheduled Principal Balance of the
      Group II Mortgage Loans for such Distribution Date, the aggregate
      Scheduled Principal Balance of the Group I Discount Mortgage Loans for
      such Distribution Date and the aggregate Scheduled Principal Balance of
      the Group II Discount Mortgage Loans for such Distribution Date;

            (xii) the aggregate Scheduled Principal Balances of the Group I
      Mortgage Loans and Group II Mortgage Loans serviced by Wells Fargo Bank in
      its capacity as Servicer and, collectively, by the Other Servicers as of
      such Distribution Date;

            (xiii) the Group I-A Percentage and Group II-A Percentage for such
      Distribution Date;

            (xiv) the Group I-A Prepayment Percentage and Group II-A Prepayment
      Percentage for such Distribution Date;

            (xv) the Group I Class I-B-1, Class I-B-2, Class I-B-3, Class I-B-4,
      Class I-B-5 and Class I-B-6 Percentages; and Group II Class II-B-1, Class
      II-B-2, Class II-B-3, Class II-B-4, Class II-B-5 and Class II-B-6
      Percentages; for such Distribution Date;

            (xvi) the Group I Class I-B-1, Class I-B-2, Class I-B-3, Class
      I-B-4, Class I-B-5 and Class I-B-6 Prepayment Percentages and Group II
      Class II-B-1, Class II-B-2, Class II-B-3, Class II-B-4, Class II-B-5 and
      Class II-B-6 Prepayment Percentages; for such Distribution Date;

            (xvii) the number and aggregate principal balances of Group I
      Mortgage Loans and Group II Mortgage Loans delinquent (A) delinquent
      (exclusive of Mortgage Loans in foreclosure or bankruptcy), grouping such
      delinquent Mortgage Loans in 30 day increments, up to 180 days delinquent
      (determined in accordance with the Mortgage Bankers' Association
      delinquency methodology), (B) in foreclosure, as of the close of business
      on the last day of the calendar month preceding the Distribution Date and
      (C) in bankruptcy as of the close of business on the last day of the
      calendar month preceding the Distribution Date;

            (xviii) the number and aggregate principal balances of the Group I
      Mortgage Loans and Group II Mortgage Loans (A) as to which foreclosure
      proceedings have been commenced as of the preceding Determination Date and
      (B) in bankruptcy as of the preceding Determination Date;

            (xix) the number and aggregate principal balances of the Mortgage
      Loans that are REO Mortgage Loans as of the Determination Date immediately
      preceding such Distribution Date;

            (xx) the aggregate amount of Realized Losses incurred during the
      preceding calendar month with respect to Group I Mortgage Loans and Group
      II Mortgage Loans allocated as of such Distribution Date;

            (xxi) any expenses or indemnification amounts paid by the Trust, the
      specific purpose of each payment and the parties to whom the payments were
      made;

            (xxii) the amount by which the Principal Balance of each Class of
      Group I-B or Group II-B Certificates has been reduced as a result of
      Realized Losses with respect to the Mortgage Loans in the related Loan
      Group allocated as of such Distribution Date;

            (xxiii) the amount of the aggregate Servicing Fees and Master
      Servicing Fees paid (and not previously reported) with respect to the
      related Distribution Date and the amount by which the aggregate Available
      Master Servicer Compensation for each Loan Group has been reduced by the
      Prepayment Interest Shortfall for such Loan Group for the related
      Distribution Date;

            (xxiv) the amount of PMI Advances made by a Servicer, if any with
      respect to each Loan Group;

            (xxv) the Class A Pass-Through Rate for each Class of Class A
      Certificates and the Class B Pass-Through Rate for each Class of Class B
      Certificates;

            (xxvi) in the case of each Class of LIBOR Certificates, the
      applicable Class A Pass-Through Rate;

            (xxvii) in the case of the Class I-A-6 Certificates, the Notional
      Amount, if any;

            (xxviii) the Yield Maintenance Agreement Payments received from the
      Counterparty;

            (xxix) the Class I-A-PO Deferred Amount and Class II-A-PO Deferred
      Amount, if any

            (xxx) any material modifications, extensions or waivers to Mortgage
      Loan terms, fees, penalties or payments since the previous Distribution
      Date;

            (xxxi) any material breaches of representations and warranties
      relating to the Group I Mortgage Loans or Group II Mortgage Loans or
      material breaches of transaction covenants;

            (xxxii) if either of the Group I Mortgage Loans or Group II Mortgage
      Loans have prepayment penalties, the aggregate amount of any prepayment
      penalties paid; and

            (xxxiii) any other customary information as is required to enable
      Certificateholders to prepare their tax returns.

      In the case of information furnished with respect to a Class of Class A
Certificates pursuant to clauses (ii) and (iii) above and with respect to a
Class of Class B Certificates pursuant to clauses (iv) and (v) above, the
amounts shall be expressed as a dollar amount per Class A or Class B Certificate
(other than the Class I-A-R Certificate) with a $1,000 Denomination, and as a
dollar amount per Class I-A-R Certificate with a $100 Denomination.

      Within a reasonable period of time after the end of each calendar year,
the Paying Agent shall, upon request, furnish or cause to be furnished to each
Person who at any time during the calendar year was the Holder of a Certificate
a statement containing the information set forth in clauses (ii) and (iii)(A)
above in the case of a Class A Certificateholder and the information set forth
in clauses (iv) and (v)(A) above in the case of a Class B Certificateholder
aggregated for such calendar year or applicable portion thereof during which
such Person was a Certificateholder. Such obligation of the Paying Agent shall
be deemed to have been satisfied to the extent that substantially comparable
information shall be provided by the Master Servicer or the Trustee pursuant to
any requirements of the Code from time to time in force.

      Unless the Master Servicer is acting as the Paying Agent, prior to the
close of business on the second Business Day preceding each Distribution Date,
the Master Servicer shall furnish a statement to any Paying Agent (the
information in such statement to be made available to Certificateholders by the
Paying Agent on written request) setting forth the Group I-A Distribution Amount
or Group II-A Distribution Amount, as applicable, with respect to each Class of
Class A Certificates and the Group I-B Distribution Amount and Group II-B
Distribution Amount with respect to each Class of Class B Certificates. The
determination by the Master Servicer of such amounts shall, in the absence of
obvious error, be presumptively deemed to be correct for all purposes hereunder
and the Trustee and the Paying Agent shall be protected in relying upon the same
without any independent check or verification.

      In addition to the Distribution Date Statements and the annual statements
required pursuant to this Section 4.04(a), the Paying Agent shall make available
upon request to each Holder and each proposed transferee of a Class I-B-4, Class
I-B-5, Class I-B-6, Class II-B-4, Class II-B-5 or Class II-B-6 Certificate such
additional information, if any, as may be required to permit the proposed
transfer to be effected pursuant to Rule 144A, which information shall be
provided on a timely basis to the Paying Agent by the Master Servicer.

      (b) The Master Servicer's responsibility for disbursing the information
set forth in subsection (a) of this Section 4.04 to each Holder of a
Certificate, the Depositor and other interested parties is limited to the
availability, timeliness and the accuracy of the information provided by each
Servicer. The Master Servicer will make a copy of each Distribution Date
Statement provided pursuant to this Section 4.04 (and, at its option, any
additional files containing the same information in an alternative format)
available each month to Certificateholders and other interested parties, and
other parties to this Agreement via the Master Servicer's internet website,
which in the case of Wells Fargo Bank, is located at "www.ctslink.com." In
addition, the Paying Agent shall provide copies of the Distribution Date
Statement and the annual statements required pursuant to Section 4.04(a) to
Persons making written requests therefor at its Corporate Trust Office.
Assistance in using the internet website can be obtained by calling the Master
Servicer's customer service desk, which in the case of Wells Fargo Bank, is at
(301) 815-6600. Parties that are unable to use the above distribution method are
entitled to have a paper copy mailed to them via first class mail by calling the
customer service desk and indicating such. The Master Servicer shall have the
right to change the way the Distribution Date Statement is distributed in order
to make such distribution more convenient and/or more accessible and the Master
Servicer shall provide timely and adequate notification to the
Certificateholders and the parties to this Agreement regarding any such changes.

      The Master Servicer shall also be entitled to rely on but shall not be
responsible for the content or accuracy of any information provided by third
parties for purposes of preparing the Distribution Date Statement and may affix
thereto any disclaimer it deems appropriate in its reasonable discretion
(without suggesting liability on the part of any other party hereto).

      Section 4.05 Reports to Mortgagors and the Internal Revenue Service.

      The Master Servicer shall, in each year beginning after the Cut-Off Date,
cause the applicable Servicers to make the reports of foreclosures and
abandonments of any Mortgaged Property as required by Code Section 6050J. In
order to facilitate this reporting process, the Master Servicer shall request
that each Servicer, on or before January 15th of each year, shall provide to the
Internal Revenue Service, with copies to the Master Servicer, reports relating
to each instance occurring during the previous calendar year in which such
Servicer (i) on behalf of the Trustee acquires an interest in a Mortgaged
Property through foreclosure or other comparable conversion in full or partial
satisfaction of a Mortgage Loan serviced by such Servicer, or (ii) knows or has
reason to know that a Mortgaged Property has been abandoned. Reports from the
Servicers shall be in form and substance sufficient to meet the reporting
requirements imposed by Code Section 6050J. In addition, each Servicer shall
provide the Master Servicer with sufficient information to allow the Master
Servicer to, for each year ending after the Cut-Off Date, provide, or cause to
be provided, to the Internal Revenue Service and the Mortgagors such information
as is required under Code Sections 6050H (regarding payment of interest) and
6050P (regarding cancellation of indebtedness).

      Section 4.06 Calculation of Amounts; Binding Effect of Interpretations and
Actions of Master Servicer.

      The Master Servicer will compute the amount of all distributions to be
made on the Certificates and all losses to be allocated to the Certificates. In
the event that the Master Servicer concludes that any ambiguity or uncertainty
exists in any provisions of this Agreement relating to distributions to be made
on the Certificates, the allocation of losses to the Certificates or otherwise,
the interpretation of such provisions and any actions taken by the Master
Servicer in good faith to implement such interpretation shall be binding upon
Certificateholders.

      Section 4.07 Determination of LIBOR.

      On each Rate Determination Date, the Paying Agent shall determine LIBOR
for the Distribution Date occurring in the succeeding month, on the basis of the
British Bankers' Association ("BBA") "Interest Settlement Rate" for one-month
deposits in U.S. dollars as found on Telerate page 3750 as of 11:00 A.M. London
time on such Rate Determination Date. As used herein, "Telerate page 3750" means
the display designated as page 3750 on the Moneyline Telerate Service.

      If on any Rate Determination Date the Paying Agent is unable to determine
LIBOR on the basis of the method set forth in the preceding paragraph, LIBOR for
the applicable Distribution Date will be whichever is higher of (x) LIBOR as
determined on the previous Rate Determination Date or (y) the Reserve Interest
Rate. The "Reserve Interest Rate" will be the rate per annum which the Paying
Agent determines to be either (A) the arithmetic mean (rounding such arithmetic
mean upwards if necessary to the nearest whole multiple of 1/16%) of the
one-month U.S. dollar lending rates that the Reference Banks are quoting, on the
relevant Rate Determination Date, to the principal London offices of at least
two leading banks in the London interbank market or (b) in the event that the
Paying Agent can determine no such arithmetic mean, the lowest one-month U.S.
dollar lending rate that the Reference Banks are quoting on such Rate
Determination Date to leading European banks.

      If on any Rate Determination Date the Paying Agent is required but is
unable to determine the Reserve Interest Rate in the manner provided in the
preceding paragraph, LIBOR for the applicable Distribution Date will be LIBOR as
determined on the previous Rate Determination Date, or, in the case of the first
Rate Determination Date, 4.72%.

      The establishment of LIBOR by the Paying Agent and the Paying Agent's
subsequent calculation of the rates of interest applicable to each of the LIBOR
Certificates in the absence of manifest error, will be final and binding. After
a Rate Determination Date, the Paying Agent shall provide the Class A
Pass-Through Rates of the LIBOR Certificates for the related Distribution Date
to Beneficial Owners or Holders of LIBOR Certificates who place a telephone call
to the Paying Agent at (301) 815-6600 and make a request therefor during normal
working hours on any Business Day.

      Section 4.08 Reserve Fund

      (a) The Master Servicer shall establish and maintain the Reserve Fund,
held in trust for the benefit of the Holders of the Class I-A-5 Certificates.
The Master Servicer shall deposit in the Reserve Fund on the date received by
it, any Yield Maintenance Agreement Payment received from the Counterparty for
the related Distribution Date. Funds on deposit in the Reserve Fund shall remain
uninvested. On each Distribution Date, the Master Servicer shall withdraw from
the Reserve Fund any Yield Maintenance Agreement Payment received in respect of
such Distribution Date and shall distribute such amounts to the Class I-A-5
Certificates.

(b) The Master Servicer shall account for the Reserve Fund and the Yield
Maintenance Agreement and the rights with respect thereto as assets of the Trust
Estate and not as assets of either REMIC created pursuant to this Agreement. The
beneficial owner of the Reserve Fund is the Holder of the Class I-A-R
Certificate. The Master Servicer shall treat the portions of the Trust Estate
consisting of the Reserve Fund and the Yield Maintenance Agreement and rights
with respect thereto as a "grantor trust" under the Code, and the provisions
hereof shall be interpreted consistently with this treatment. The Master
Servicer shall furnish or cause to be furnished (i) to the Holders of the Class
I-A-5 Certificates and (ii) to Holder of the Class I-A-R Certificate, and shall
file or cause to be filed with the Internal Revenue Service together with Form
1041 or such other form as may be applicable, their allocable shares of income
and expenses with respect to the property held by the Grantor Trust, at the time
or times and in the manner required by the Code.

(c) Any amounts in the Reserve Fund paid by the Master Servicer pursuant to this
Section 4.08 to the Class I-A-5 Certificates shall be accounted for by the
Master Servicer as amounts paid to the Class I-A-5 Certificates from the Grantor
Trust. In addition, the Master Servicer shall account for the rights of the
Class I-A-5 Certificates to receive amounts from the Reserve Fund as rights in a
limited recourse interest rate cap contract written by the Counterparty in favor
of the Class I-A-5 Certificates.


                                    ARTICLE V

                                THE CERTIFICATES

      Section 5.01 The Certificates.

      (a) The Class A and Class B Certificates shall be issued only in minimum
Denominations of a Single Certificate and, except for the Class I-A-R
Certificate, integral multiples of $1,000 in excess thereof (except, if
necessary, for one Certificate of each Class (other than the Class I-A-R
Certificate) that evidences one Single Certificate plus such additional
principal portion or notional amount as is required in order for all
Certificates of such Class to equal the aggregate Original Principal Balance or
Original Notional Amount of such Class, as the case may be), and shall be
substantially in the respective forms set forth as Exhibits A-I-A-1, A-I-A-2,
A-I-A-3, A-I-A-4, A-I-A-5, A-I-A-6, A-I-A-7, A-I-A-8, A-I-A-9, A-I-A-10,
A-I-A-11, A-I-A-12, A-I-A-13, A-I-A-14, A-I-A-R, A-I-A-PO, A-II-A-1, A-II-A-2,
A-II-A-3, A-II-A-PO, I-B-1, I-B-2, I-B-3, I-B-4, I-B-5, I-B-6, II-B-1, II-B-2,
II-B-3, II-B-4, II-B-5, II-B-6 and C (reverse side of Certificates) hereto. On
original issue the Certificates shall be executed and delivered by the Paying
Agent to or upon the order of the Depositor upon receipt by the Trustee or the
Custodian of the documents specified in Section 2.01(a). The aggregate principal
portion evidenced by the Class A and Class B Certificates shall be the sum of
the amounts specifically set forth in the respective Certificates. The
Certificates shall be executed by manual or facsimile signature on behalf of the
Paying Agent by any Responsible Officer thereof. Certificates bearing the manual
or facsimile signatures of individuals who were at any time the proper officers
of the Paying Agent shall bind the Paying Agent notwithstanding that such
individuals or any of them have ceased to hold such offices prior to the
countersigning of such Certificates and delivery of such Certificates or did not
hold such offices at the date of such Certificates. No Certificate shall be
entitled to any benefit under this Agreement, or be valid for any purpose,
unless manually countersigned by a Responsible Officer of the Authenticating
Agent, or unless there appears on such Certificate a certificate of
authentication executed by the Authenticating Agent by manual signature, and
such countersignature or certificate upon a Certificate shall be conclusive
evidence, and the only evidence, that such Certificate has been duly
authenticated and delivered hereunder. All Certificates shall be dated the date
of their authentication.

      Until such time as Definitive Certificates are issued pursuant to Section
5.07, each Book-Entry Certificate shall bear the following legend:

      "Unless this certificate is presented by an authorized representative of
[the Clearing Agency] to the Depositor or its agent for registration of
transfer, exchange or payment, and any certificate issued is registered in the
name of [the Clearing Agency] or such other name as requested by an authorized
representative of [the Clearing Agency] and any payment is made to [the Clearing
Agency], any transfer, pledge or other use hereof for value or otherwise by or
to any person is wrongful since the registered owner hereof, [the Clearing
Agency], has an interest herein."

      (b) Upon original issuance, the Book-Entry Certificates shall be issued in
the form of one or more typewritten certificates, to be delivered to The
Depository Trust Company, the initial Clearing Agency, by, or on behalf of, the
Depositor or to, and deposited with the Certificate Custodian, on behalf of The
Depository Trust Company, if directed to do so pursuant instructions from The
Depository Trust Company. Such Certificates shall initially be registered in the
Certificate Register in the name of the nominee of the initial Clearing Agency,
and no Beneficial Owner will receive a definitive certificate representing such
Beneficial Owner's interest in the Book-Entry Certificates, except as provided
in Section 5.07. Unless and until definitive, fully registered certificates
("Definitive Certificates") have been issued to Beneficial Owners pursuant to
Section 5.07:

            (i) the provisions of this Section 5.01(b) shall be in full force
      and effect;

            (ii) the Depositor, the Master Servicer, the Certificate Registrar,
      the Paying Agent and the Trustee may deal with the Clearing Agency for all
      purposes (including the making of distributions on the Book-Entry
      Certificates and the taking of actions by the Holders of Book-Entry
      Certificates) as the authorized representative of the Beneficial Owners;

            (iii) to the extent that the provisions of this Section 5.01(b)
      conflict with any other provisions of this Agreement, the provisions of
      this Section 5.01(b) shall control;

            (iv) the rights of Beneficial Owners shall be exercised only through
      the Clearing Agency and shall be limited to those established by law, the
      rules, regulations and procedures of the Clearing Agency and agreements
      between such Beneficial Owners and the Clearing Agency and/or the Clearing
      Agency Participants, and all references in this Agreement to actions by
      Certificateholders shall, with respect to the Book-Entry Certificates,
      refer to actions taken by the Clearing Agency upon instructions from the
      Clearing Agency Participants, and all references in this Agreement to
      distributions, notices, reports and statements to Certificateholders
      shall, with respect to the Book-Entry Certificates, refer to
      distributions, notices, reports and statements to the Clearing Agency or
      its nominee, as registered holder of the Book-Entry Certificates, as the
      case may be, for distribution to Beneficial Owners in accordance with the
      procedures of the Clearing Agency; and

            (v) the initial Clearing Agency will make book-entry transfers among
      the Clearing Agency Participants and receive and transmit distributions of
      principal and interest on the Certificates to the Clearing Agency
      Participants, for distribution by such Clearing Agency Participants to the
      Beneficial Owners or their nominees.

      For purposes of any provision of this Agreement requiring or permitting
actions with the consent of, or at the direction of, Holders of Book-Entry
Certificates evidencing specified Voting Interests, such direction or consent
shall be given by Beneficial Owners having the requisite Voting Interests,
acting through the Clearing Agency.

      Unless and until Definitive Certificates have been issued to Beneficial
Owners pursuant to Section 5.07, copies of the Distribution Date Statements
shall be available to Beneficial Owners upon written request to the Paying Agent
at its Corporate Trust Office.

      Section 5.02 Registration of Certificates.

      (a) The Certificate Registrar shall cause to be kept at one of the offices
or agencies to be maintained in accordance with the provisions of Section 5.06 a
Certificate Register in which, subject to such reasonable regulations as it may
prescribe, the Certificate Registrar shall provide for the registration of
Certificates and of transfers and exchanges of Certificates as herein provided.
The Master Servicer shall act as, or shall appoint, a Certificate Registrar for
the purpose of registering Certificates and transfers and exchanges of
Certificates as herein provided.

      Upon surrender for registration of transfer of any Certificate at any
office or agency maintained for such purpose pursuant to Section 5.06 (and
subject to the provisions of this Section 5.02) the Paying Agent shall execute,
and shall date, countersign (or cause the Authenticating Agent to countersign)
and deliver, in the name of the designated transferee or transferees, one or
more new Certificates of a like aggregate principal portion or Percentage
Interest and of the same Class.

      At the option of the Certificateholders, Certificates may be exchanged for
other Certificates of authorized Denominations of a like aggregate principal
portion or Percentage Interest and of the same Class upon surrender of the
Certificates to be exchanged at any such office or agency. Whenever any
Certificates are so surrendered for exchange, the Paying Agent shall execute,
and shall date, countersign (or cause the Authenticating Agent to countersign)
and deliver, the Certificates which the Certificateholder making the exchange is
entitled to receive. Every Certificate presented or surrendered for transfer or
exchange shall (if so required by the Certificate Registrar or the Paying Agent)
be duly endorsed by, or be accompanied by a written instrument of transfer in
form satisfactory to the Certificate Registrar, duly executed by the Holder
thereof or his attorney duly authorized in writing.

      No service charge shall be made for any transfer or exchange of
Certificates, but the Certificate Registrar may require payment of a sum
sufficient to cover any tax or governmental charge that may be imposed in
connection with any transfer or exchange of Certificates.

      All Certificates surrendered for transfer and exchange shall be canceled
by the Certificate Registrar, the Paying Agent or the Authenticating Agent in
accordance with their standard procedures.

      (b) No transfer of a Class I-B-4, Class I-B-5, Class I-B-6, Class II-B-4,
Class II-B-5 or Class II-B-6 Certificate shall be made unless the registration
requirements of the 1933 Act and any applicable State securities laws are
complied with, or such transfer is exempt from the registration requirements
under said Act and laws. In the event that a transfer is to be made in reliance
upon an exemption from said Act or laws, (i) unless such transfer is made in
reliance on Rule 144A, the Master Servicer or the Depositor may, if such
transfer is to be made within three years after the later of (a) the date of the
initial sale of Certificates or (b) the last date on which the Depositor or any
affiliate thereof was a Holder of the Certificates proposed to be transferred,
require a Class I-B-4, Class I-B-5, Class I-B-6, Class II-B-4, Class II-B-5 or
Class II-B-6 Certificateholder to deliver a written Opinion of Counsel
acceptable to and in form and substance satisfactory to the Master Servicer and
the Depositor, to the effect that such transfer may be made pursuant to an
exemption, describing the applicable exemption and the basis therefor, from said
Act and laws or is being made pursuant to said Act and laws, which Opinion of
Counsel shall not be an expense of the Depositor or the Master Servicer, and
(ii) the Master Servicer shall require the transferee (other than an affiliate
of the Depositor on the Closing Date) to execute an investment letter in the
form of Exhibit J hereto certifying to the Depositor and the Master Servicer the
facts surrounding such transfer, which investment letter shall not be an expense
of the Depositor or the Master Servicer. The Holder of a Class I-B-4, Class
I-B-5, Class I-B-6, Class II-B-4, Class II-B-5 or Class II-B-6 Certificate
desiring to effect such transfer shall, and does hereby agree to, indemnify the
Trustee, the Depositor, the Master Servicer and any Paying Agent against any
liability that may result if the transfer is not so exempt or is not made in
accordance with such federal and state laws. Neither the Depositor nor the
Master Servicer is under an obligation to register the Class I-B-4, Class I-B-5,
Class I-B-6, Class II-B-4, Class II-B-5 or Class II-B-6 Certificates under said
Act or any other securities law.

      (c) No transfer of a Class I-B-4, Class I-B-5, Class I-B-6, Class II-B-4,
Class II-B-5 or Class II-B-6 Certificate shall be made unless the Master
Servicer and the Depositor shall have received (i) a representation letter from
the transferee in the form of Exhibit J hereto, to the effect that either (a)
such transferee is not an employee benefit plan or other retirement arrangement
subject to Title I of ERISA or Code Section 4975, or a governmental plan, as
defined in Section 3(32) of ERISA, subject to any federal, state or local law
("Similar Law") which is to a material extent similar to the foregoing
provisions of ERISA or the Code (collectively, a "Plan") and is not a person
acting on behalf of or using the assets of any such Plan, which representation
letter shall not be an expense of the Depositor or the Master Servicer or (b) if
such transferee is an insurance company, (A) the source of funds used to
purchase the Class I-B-4, Class I-B-5, Class I-B-6, Class II-B-4, Class II-B-5
or Class II-B-6 Certificate is an "insurance company general account" (as such
term is defined in Section V(e) of Prohibited Transaction Class Exemption 95-60
("PTE 95-60"), 60 Fed. Reg. 35925 (July 12, 1995)), (B) there is no Plan with
respect to which the amount of such general account's reserves and liabilities
for the contract(s) held by or on behalf of such Plan and all other Plans
maintained by the same employer (or affiliate thereof as defined in Section
V(a)(1) of PTE 95-60) or by the same employee organization exceeds 10% of the
total of all reserves and liabilities of such general account (as such amounts
are determined under Section I(a) of PTE 95-60) at the date of acquisition and
(C) the purchase and holding of such Class I-B-4, Class I-B-5, Class I-B-6,
Class II-B-4, Class II-B-5 or Class II-B-6 Certificate is covered by Sections I
and III of PTE 95-60 or (ii) in the case of any such Class I-B-4, Class I-B-5,
Class I-B-6, Class II-B-4, Class II-B-5 or Class II-B-6 Certificate presented
for registration in the name of a Plan, or a trustee of any such Plan, (A) an
Opinion of Counsel satisfactory to the Master Servicer and the Depositor to the
effect that the purchase or holding of such Class I-B-4, Class I-B-5, Class
I-B-6, Class II-B-4, Class II-B-5 or Class II-B-6 Certificate will not
constitute or result in a non-exempt prohibited transaction within the meaning
of ERISA, Section 4975 of the Code or Similar Law and will not subject the
Depositor or the Master Servicer to any obligation in addition to those
undertaken in this Agreement, which Opinion of Counsel shall not be an expense
of the Depositor or the Master Servicer and (B) such other opinions of counsel,
Officer's Certificates and agreements as the Depositor or the Master Servicer
may require in connection with such transfer, which opinions of counsel,
Officer's Certificates and agreements shall not be an expense of the Depositor
or the Master Servicer. The Class I-B-4, Class I-B-5, Class I-B-6, Class II-B-4,
Class II-B-5 and Class II-B-6 Certificates shall bear a legend referring to the
foregoing restrictions contained in this paragraph.

      (d) No legal or beneficial interest in all or any portion of the Class
I-A-R Certificate may be transferred directly or indirectly to a "disqualified
organization" within the meaning of Code Section 860E(e)(5) or an agent of a
disqualified organization (including a broker, nominee, or middleman), to a Plan
or a Person acting on behalf of or investing the assets of a Plan (such Plan or
Person, an "ERISA Prohibited Holder") or to an individual, corporation,
partnership or other person unless such transferee (i) is not a Non-U.S. Person
or (ii) is a Non-U.S. Person that holds the Class I-A-R Certificate in
connection with the conduct of a trade or business within the United States and
has furnished the transferor and the Master Servicer with an effective Internal
Revenue Service Form W-8ECI or (iii) is a Non-U.S. Person that has delivered to
both the transferor and the Master Servicer an opinion of a nationally
recognized tax counsel to the effect that the transfer of the Class I-A-R
Certificate to it is in accordance with the requirements of the Code and the
regulations promulgated thereunder and that such transfer of the Class I-A-R
Certificate will not be disregarded for federal income tax purposes (any such
person who is not covered by clauses (i), (ii) or (iii) above being referred to
herein as a "Non-permitted Foreign Holder"), and any such purported transfer
shall be void and have no effect. The Paying Agent shall not execute, and shall
not countersign (or cause the Authenticating Agent to countersign) and deliver,
a new Class I-A-R Certificate in connection with any such transfer to a
disqualified organization or agent thereof (including a broker, nominee or
middleman), an ERISA Prohibited Holder or a Non-permitted Foreign Holder, and
neither the Certificate Registrar nor the Paying Agent shall accept a surrender
for transfer or registration of transfer, or register the transfer of, the Class
I-A-R Certificate, unless the transferor shall have provided to the Master
Servicer an affidavit, substantially in the form attached as Exhibit H hereto,
signed by the transferee, to the effect that the transferee is not such a
disqualified organization, an agent (including a broker, nominee, or middleman)
for any entity as to which the transferee has not received a substantially
similar affidavit, an ERISA Prohibited Holder or a Non-permitted Foreign Holder,
which affidavit shall contain the consent of the transferee to any such
amendments of this Agreement as may be required to further effectuate the
foregoing restrictions on transfer of the Class I-A-R Certificate to
disqualified organizations, ERISA Prohibited Holders or Non-permitted Foreign
Holders. Such affidavit shall also contain the statement of the transferee that
(i) the transferee has historically paid its debts as they have come due and
intends to do so in the future, (ii) the transferee understands that it may
incur liabilities in excess of cash flows generated by the residual interest,
(iii) the transferee intends to pay taxes associated with holding the residual
interest as they become due, (iv) the transferee will not cause income from the
Class I-A-R Certificate to be attributable to a foreign permanent establishment
or fixed base, within the meaning of an applicable income tax treaty, of such
transferee or any other Person, and (v) the transferee will not transfer the
Class I-A-R Certificate to any Person who does not provide an affidavit
substantially in the form attached as Exhibit H hereto.

      The affidavit described in the preceding paragraph, if not executed in
connection with the initial issuance of the Class I-A-R Certificate, shall be
accompanied by a written statement in the form attached as Exhibit I hereto,
signed by the transferor, to the effect that as of the time of the transfer, the
transferor has no actual knowledge that the transferee is a disqualified
organization, ERISA Prohibited Holder or Non-permitted Foreign Holder, and has
no knowledge or reason to know that the statements made by the transferee with
respect to clauses (i) and (iii) of the last sentence of the preceding paragraph
are not true. The Class I-A-R Certificate shall bear a legend referring to the
foregoing restrictions contained in this paragraph and the preceding paragraph.

      Upon actual knowledge of a Master Servicing Officer or a Responsible
Officer of the Paying Agent that any legal or beneficial interest in any portion
of the Class I-A-R Certificate has been transferred, directly or indirectly, to
a disqualified organization or agent thereof (including a broker, nominee, or
middleman) in contravention of the foregoing restrictions, (i) such transferee
shall be deemed to hold the Class I-A-R Certificate in constructive trust for
the last transferor who was not a disqualified organization or agent thereof,
and such transferor shall be restored as the owner of such Class I-A-R
Certificate as completely as if such transfer had never occurred, provided that
the Master Servicer may, but is not required to, recover any distributions made
to such transferee with respect to the Class I-A-R Certificate, and (ii) the
Master Servicer agrees to furnish to the Internal Revenue Service and to any
transferor of the Class I-A-R Certificate or such agent (within 60 days of the
request therefor by the transferor or agent) such information necessary to the
application of Code Section 860E(e) as may be required by the Code, including
but not limited to the present value of the total anticipated excess inclusions
with respect to the Class I-A-R Certificate (or portion thereof) for periods
after such transfer. At the election of the Master Servicer, the cost to the
Master Servicer of computing and furnishing such information may be charged to
the transferor or such agent referred to above; however, the Master Servicer
shall in no event be excused from furnishing such information.

      Section 5.03 Mutilated, Destroyed, Lost or Stolen Certificates.

      If (i) any mutilated Certificate is surrendered to the Paying Agent, the
Certificate Registrar or the Authenticating Agent, or the Paying Agent, the
Certificate Registrar or the Authenticating Agent receives evidence to its
satisfaction of the destruction, loss or theft of any Certificate, and (ii)
there is delivered to the Paying Agent, the Certificate Registrar or the
Authenticating Agent such security or indemnity as may be required by them to
hold each of them harmless, then, in the absence of notice to the Paying Agent,
the Certificate Registrar or the Authenticating Agent that such Certificate has
been acquired by a bona fide purchaser, the Paying Agent shall execute and
countersign (or cause the Authenticating Agent to countersign) and deliver, in
exchange for or in lieu of any such mutilated, destroyed, lost or stolen
Certificate, a new Certificate of like tenor and principal portion or Percentage
Interest and of the same Class. Upon the issuance of any new Certificate under
this Section, the Paying Agent or the Certificate Registrar may require the
payment of a sum sufficient to cover any tax or other governmental charge that
may be imposed in relation thereto and any other expense (including the fees and
expenses of the Paying Agent or the Authenticating Agent) in connection
therewith. Any duplicate Certificate issued pursuant to this Section shall
constitute complete and indefeasible evidence of ownership in the Trust Estate,
as if originally issued, whether or not the lost, stolen, or destroyed
Certificate shall be found at any time.

      Section 5.04 Persons Deemed Owners.

      Prior to the due presentation of a Certificate for registration of
transfer, the Depositor, the Master Servicer, the Trustee, the Paying Agent, the
Certificate Registrar and any agent of the Depositor, the Master Servicer, the
Trustee, the Paying Agent or the Certificate Registrar may treat the Person in
whose name any Certificate is registered as the owner of such Certificate for
the purpose of receiving distributions pursuant to Section 4.01, and for all
other purposes whatsoever, and neither the Depositor, the Master Servicer, the
Trustee, the Certificate Registrar, the Paying Agent nor any agent of the
Depositor, the Master Servicer, the Trustee, the Certificate Registrar or the
Paying Agent shall be affected by notice to the contrary.

      Section 5.05 Access to List of Certificateholders' Names and Addresses.

      (a) If the Paying Agent is not acting as Certificate Registrar, the
Certificate Registrar shall furnish or cause to be furnished to the Paying
Agent, within 15 days after receipt by the Certificate Registrar of a request by
the Paying Agent in writing, a list, in such form as the Paying Agent may
reasonably require, of the names and addresses of the Certificateholders of each
Class as of the most recent Record Date.

      (b) If five or more Certificateholders (hereinafter referred to as
"applicants") apply in writing to the Certificate Registrar, and such
application states that the applicants desire to communicate with other
Certificateholders with respect to their rights under this Agreement or under
the Certificates and is accompanied by a copy of the communication which such
applicants propose to transmit, then the Certificate Registrar shall, within
five Business Days following the receipt of such application, afford such
applicants access during normal business hours to the most recent list of
Certificateholders held by the Certificate Registrar.

      (c) Every Certificateholder, by receiving and holding a Certificate,
agrees with the Depositor, the Master Servicer, the Certificate Registrar, the
Paying Agent and the Trustee that neither the Depositor, the Master Servicer,
the Certificate Registrar, the Paying Agent nor the Trustee shall be held
accountable by reason of the disclosure of any such information as to the names,
addresses and Percentage Interests of the Certificateholders hereunder,
regardless of the source from which such information was delivered.

      Section 5.06 Maintenance of Office or Agency.

      The Certificate Registrar will maintain, at its expense, an office or
agency where Certificates may be surrendered for registration of transfer or
exchange and where notices and demands to or upon the Certificate Registrar in
respect of the Certificates and this Agreement may be served. The Certificate
Registrar initially designates the Corporate Trust Office of the Certificate
Registrar, if any, as its offices and agencies for said purposes.

      Section 5.07 Definitive Certificates.

      If (A) the Clearing Agency advises the Paying Agent in writing that the
Clearing Agency is no longer willing or able properly to discharge its
responsibilities as depository with respect to the Book-Entry Certificates, and
(B) the Depositor is unable to locate a qualified successor, the Paying Agent
shall notify the Beneficial Owners, through the Clearing Agency, of the
occurrence of any such event and of the availability of Definitive Certificates
to Beneficial Owners requesting the same. Upon surrender to the Paying Agent by
the Clearing Agency of the Certificates held of record by its nominee,
accompanied by reregistration instructions and directions to execute and
authenticate new Certificates from the Depositor, the Paying Agent shall execute
and cause the Authenticating Agent to countersign Definitive Certificates for
delivery at its Corporate Trust Office. The Depositor shall arrange for, and
will bear all costs of, the printing and issuance of such Definitive
Certificates. Except with the consent of the Depositor, the Paying Agent shall
not execute or cause the Authenticating Agent to countersign Definitive
Certificates in exchange for Book-Entry Certificates except as set forth above.
Neither the Depositor, the Master Servicer nor the Paying Agent shall be liable
for any delay in delivery of such instructions by the Clearing Agency and may
conclusively rely on, and shall be protected in relying on, such instructions.

      Section 5.08 Notices to Clearing Agency.

      Whenever notice or other communication to the Holders of Book-Entry
Certificates is required under this Agreement, unless and until Definitive
Certificates shall have been issued to Beneficial Owners pursuant to Section
5.07, the Paying Agent shall give all such notices and communications specified
herein to be given to Holders of Book-Entry Certificates to the Clearing Agency.


                                   ARTICLE VI

                      THE DEPOSITOR AND THE MASTER SERVICER

      Section 6.01 Liability of the Depositor and the Master Servicer.

      The Depositor and the Master Servicer shall each be liable in accordance
herewith only to the extent of the obligations specifically imposed by this
Agreement and undertaken hereunder by the Depositor and the Master Servicer.

      Section 6.02 Merger or Consolidation of the Depositor or the Master
Servicer.

      Subject to the following paragraph (a) the Depositor will keep in full
effect its existence, rights and franchises as a corporation under the laws of
the jurisdiction of its incorporation, and will obtain and preserve its
qualification to do business as a foreign corporation in each jurisdiction in
which such qualification is or shall be necessary to protect the validity and
enforceability of this Agreement, the Certificates or any of the Mortgage Loans
and to perform its respective duties under this Agreement and (b) the Master
Servicer will keep in full effect its power and authority as a national banking
association under the laws of the jurisdiction of its organization, and will
obtain and preserve its qualification to do business in each jurisdiction in
which such qualification is or shall be necessary to protect the validity and
enforceability of this Agreement, the Certificates or any of the Mortgage Loans
and to perform its respective duties under this Agreement.

      The Depositor or the Master Servicer may be merged or consolidated with or
into any Person, or transfer all or substantially all of its assets to any
Person, in which case any Person resulting from any merger or consolidation to
which the Depositor or Master Servicer shall be a party, or any Person
succeeding to the business of the Depositor or Master Servicer, shall be the
successor of the Depositor or Master Servicer hereunder, without the execution
or filing of any paper or any further act on the part of any of the parties
hereto, anything herein to the contrary notwithstanding; provided, however,
that, (a) in the case of the Master Servicer, any such successor or resulting
Person shall have a net worth of not less than $15,000,000 and be qualified to
service mortgage loans for Fannie Mae or Freddie Mac and (b) the Master Servicer
and such successor or surviving Person shall notify the Depositor and the
Trustee of any such merger, conversion or consolidation at least two Business
Days prior to the effective date thereof (unless giving such prior notice would
be prohibited by applicable law or by a confidentiality agreement, in which case
notice shall be given by 12 noon eastern time one Business Day after such merger
or consolidation).

      Section 6.03 Limitation on Liability of the Depositor, the Master Servicer
and Others.

      Neither the Depositor nor the Master Servicer nor any subcontractor nor
any of the partners, directors, officers, employees or agents of any of them
shall be under any liability to the Trust Estate or the Certificateholders and
all such Persons shall be held harmless for any action taken or for refraining
from the taking of any action in good faith pursuant to this Agreement, or for
errors in judgment; provided, however, that this provision shall not protect any
such Person against any breach of warranties or representations made herein or
against any liability which would otherwise be imposed by reason of willful
misfeasance, bad faith or gross negligence in the performance of duties or by
reason of reckless disregard of obligations and duties hereunder. The Depositor,
the Master Servicer, any subcontractor, and any director, officer, employee or
agent of any of them shall be entitled to indemnification by the Trust Estate
and will be held harmless against any loss, liability or expense incurred in
connection with the performance of their duties and obligations, the exercise of
their rights or any legal action (including but not limited to, costs and
expenses of litigation, and of investigation, attorney's fees, damages,
judgments and amounts paid in settlement) under this Agreement, the Certificates
or the Mortgage Loans (except for amounts due by the Depositor in connection
with the breach of a representation or warranty covering the Mortgage Loans),
including, in the case of the Master Servicer, any indemnity amounts paid by the
Master Servicer to a Servicer pursuant to the applicable Servicing Agreement,
other than any loss, liability or expense (including without limitation,
expenses payable by the Master Servicer under Section 8.06) incurred by reason
of willful misfeasance, bad faith or gross negligence in the performance of his
or its duties hereunder or by reason of reckless disregard of his or its
obligations and duties hereunder. The Depositor, the Master Servicer and any of
the directors, officers, employees or agents of either may rely in good faith on
any document of any kind which, prima facie, is properly executed and submitted
by any Person respecting any matters arising hereunder. Neither the Depositor
nor the Master Servicer shall be under any obligation to appear in, prosecute or
defend any legal action unless such action is related to its respective duties
under this Agreement and, in its opinion, does not involve it in any expense or
liability; provided, however, that the Depositor or the Master Servicer may in
its discretion undertake any such action which it may deem necessary or
desirable with respect to this Agreement and the rights and duties of the
parties hereto and the interests of the Certificateholders hereunder if the
Certificateholders offer to the Depositor or the Master Servicer, as the case
may be, reasonable security or indemnity against the costs, expenses and
liabilities which may be incurred therein or thereby. In such event, the legal
expenses and costs of such action and any liability resulting therefrom shall be
expenses, costs and liabilities of the Trust Estate, and the Depositor or the
Master Servicer shall be entitled to be reimbursed therefor out of the
Certificate Account, and such amounts shall, on the following Distribution Date
or Distribution Dates, be allocated in reduction of distributions on the Class A
Certificates and Class B Certificates in the same manner as Realized Losses are
allocated pursuant to Section 4.02(a).

      Section 6.04 Resignation of the Master Servicer.

      The Master Servicer shall not resign from the obligations and duties
hereby imposed on it except (a) upon appointment of a successor master servicer
and receipt by the Trustee of a letter from each Rating Agency that such a
resignation and appointment will not result in a downgrading of the rating of
any of the Certificates, (b) upon determination that its duties hereunder are no
longer permissible under applicable law, or (c) pursuant to Section 6.06. Any
such determination under clause (b) permitting the resignation of the Master
Servicer shall be evidenced by an Opinion of Counsel to such effect delivered to
the Trustee. No such resignation shall become effective until the Trustee or a
successor master servicer shall have assumed the Master Servicer's
responsibilities, duties, liabilities and obligations hereunder.

      Section 6.05 Compensation to the Master Servicer.

      The Master Servicer shall be entitled to receive a monthly fee equal to
the Master Servicing Fee, as compensation for services rendered by the Master
Servicer under this Agreement. The Master Servicer also will be entitled to any
late reporting fees paid by a Servicer pursuant to its Servicing Agreement, any
investment income on funds on deposit in the Certificate Account invested in
accordance with Section 3.01(c), any investment income on funds on deposit in
the Payment Account invested in accordance with Section 4.03(a) and any
Liquidation Profits to which a Servicer is not entitled under its Servicing
Agreement.

      Section 6.06 Assignment or Delegation of Duties by Master Servicer.

      (a) The Master Servicer shall not assign or transfer any of its rights,
benefits or privileges under this Agreement to any other Person, or delegate to
or subcontract with, or authorize or appoint any other Person to perform any of
the duties, covenants or obligations to be performed by the Master Servicer
without the prior written consent of the Trustee, and any agreement, instrument
or act purporting to effect any such assignment, transfer, delegation or
appointment shall be void. Notwithstanding the foregoing, subject to Section
6.06(b), the Master Servicer shall have the right without the prior written
consent of the Trustee (i) to assign its rights and delegate its duties and
obligations hereunder; provided, however, that (a) the purchaser or transferee
accepting such assignment or delegation is qualified to service mortgage loans
for Fannie Mae or Freddie Mac, and executes and delivers to the Trustee an
agreement, in form and substance reasonably satisfactory to the Trustee, which
contains an assumption by such purchaser or transferee of the due and punctual
performance and observance of each covenant and condition to be performed or
observed by the Master Servicer hereunder from and after the date of such
agreement; and (b) each applicable Rating Agency's rating of any Certificates in
effect immediately prior to such assignment, sale or transfer is not reasonably
likely to be qualified, downgraded or withdrawn as a result of such assignment,
sale or transfer and the Certificates are not reasonably likely to be placed on
credit review status by any such Rating Agency; and (ii) to delegate to,
subcontract with, authorize, or appoint an affiliate of the Master Servicer to
perform and carry out any duties, covenants or obligations to be performed and
carried out by the Master Servicer under this Agreement and hereby agrees so to
delegate, subcontract, authorize or appoint to an affiliate of the Master
Servicer any duties, covenants or obligations to be performed and carried out by
the Master Servicer to the extent that such duties, covenants or obligations are
to be performed in any state or states in which the Master Servicer is not
authorized to do business as a foreign corporation but in which the affiliate is
so authorized. In no case, however, shall any permitted assignment and
delegation relieve the Master Servicer of any liability to the Trustee or the
Depositor under this Agreement, incurred by it prior to the time that the
conditions contained in clause (i) above are met.

      (b) Notwithstanding anything contained herein to the contrary, to the
extent the Master Servicer engages any affiliate or third party vendor, in
connection with the performance of any of its duties under this Agreement, the
Master Servicer shall immediately notify the Depositor in writing of such
engagement (to the extent it has not already notified the Depositor pursuant to
clause (a) above); provided however, that prior to engaging any affiliate or
third party vendor in connection with the performance of any of its duties under
this Agreement, the Master Servicer shall determine (i) if such affiliates or
third party vendors would be a Servicing Function Participant and (ii) if such
affiliate or third party vendor would be a "servicer" within the meaning of Item
1101 of Regulation AB (an "Additional Master Servicer") and meets the criteria
in Item 1108(a)(2)(i), (ii) or (iii) of Regulation AB. If the Master Servicer
has determined that such affiliates or third party vendors are a Servicing
Function Participant, the Master Servicer shall cause such Servicing Function
Participant to prepare and deliver to the Master Servicer a separate assessment
and attestation report, as contemplated by Section 3.11 of this Agreement. In
addition, if the Master Servicer has determined that any such affiliate or third
party vendor would be an Additional Master Servicer and meets the criteria in
Item 1108(a)(2)(i), (ii) or (iii) of Regulation AB, the Master Servicer shall
cause such Additional Master Servicer to prepare and deliver to the Master
Servicer a separate compliance statement as contemplated by Section 3.05 of this
Agreement. In addition, if the Master Servicer determines any such affiliate or
third party vendor would be a "servicer" within the meaning of Item 1101 of
Regulation AB, the Master Servicer shall not engage such affiliate or third
party vendor unless it provides the Master Servicer and the Depositor the
information required by Section 1108(b) and 1108(c) of Regulation AB prior to
such engagement.

      (c) In the event of any assignment of rights or delegation of duties of
the Master Servicer, the Master Servicer shall report such event on Form 8-K
within four Business Days after the effective date thereof.

      Section 6.07 Indemnification of Trustee and Depositor by Master Servicer.

      The Master Servicer shall indemnify and hold harmless the Trustee and the
Depositor and any director, officer or agent thereof against any loss, liability
or expense, including reasonable attorney's fees, arising out of, in connection
with or incurred by reason of (a) willful misfeasance, bad faith or negligence
in the performance of duties of the Master Servicer under this Agreement or by
reason of reckless disregard of its obligations and duties under this Agreement,
including, but not limited to the Master Servicer's obligation to deliver any
information, report, certification, accountants' letter or other material
required to comply with Regulation AB or (b) any material breach by the Master
Servicer of any of the representations and warranties contained in Section
2.03(a). Any payment pursuant to this Section made by the Master Servicer to the
Trustee or the Depositor shall be from such entity's own funds, without
reimbursement therefor. The provisions of this Section 6.07 shall survive the
termination of this Agreement.

      Section 6.08 Master Servicer Errors and Omissions Policy.

      The Master Servicer shall maintain, at all times and at its own expense, a
Master Servicer Errors and Omissions Policy, which policy shall have such terms
and coverage amounts as are comparable to those of errors and omissions policies
maintained by master servicers of mortgage loans generally.

      The Master Servicer Errors and Omissions Policy shall insure the Master
Servicer, its successors and assigns, against any losses resulting from
negligence, errors or omissions on the part of officers, employees or other
persons acting on behalf of the Master Servicer in the performance of its duties
as Master Servicer pursuant to this Agreement.

      The Master Servicer shall maintain in effect the Master Servicer Errors
and Omissions Policy at all times and the Master Servicer Errors and Omissions
Policy may not be canceled, permitted to lapse or otherwise terminated without
the acquisition of comparable coverage by the Master Servicer.


                                  ARTICLE VII

                                     DEFAULT

      Section 7.01 Events of Default.

      In case one or more of the following Events of Default by the Master
Servicer shall occur and be continuing, that is to say:

            (i) any failure by the Master Servicer to remit any funds to the
      Paying\ Agent as required by Section 4.03 continues unremedied for a
      period of three business days after the date upon which written notice of
      such failure, requiring the same to be remedied, shall have been given to
      the Master Servicer by the Trustee or to the Master Servicer and the
      Trustee by the holders of Certificates evidencing in the aggregate not
      less than 25% of the aggregate Voting Interest represented by all
      Certificates;

            (ii) any failure on the part of the Master Servicer to observe or
      perform in any material respect any of its covenants or agreements under
      Sections 3.05, 3.11 or 3.12 hereof, subject to any cure period set forth
      in such sections;

            (iii) any failure on the part of the Master Servicer duly to observe
      or perform in any material respect any other of the covenants or
      agreements on the part of the Master Servicer in the Certificates or in
      this Agreement, which continues unremedied for a period of 60 days after
      the date on which written notice of such failure, requiring the same to be
      remedied, shall have been given to the Master Servicer by the Trustee or
      the Depositor, or to the Master Servicer and the Trustee by the holders of
      Certificates evidencing in the aggregate not less than 25% of the
      aggregate Voting Interest represented by all Certificates;

            (iv) a decree or order of a court or agency or supervisory authority
      having jurisdiction in the premises for the appointment of a trustee,
      conservator, receiver or liquidator in any bankruptcy, insolvency,
      readjustment of debt, marshaling of assets and liabilities or similar
      proceedings, or for the winding-up or liquidation of its affairs, shall
      have been entered against the Master Servicer and such decree or order
      shall have remained in force undischarged and unstayed for a period of 60
      days;

            (v) the Master Servicer shall consent to the appointment of a
      trustee, conservator, receiver or liquidator or liquidating committee in
      any bankruptcy, insolvency, readjustment of debt, marshaling of assets and
      liabilities, voluntary liquidation or similar proceedings of or relating
      to the Master Servicer, or of or relating to all or substantially all of
      its property;

            (vi) the Master Servicer shall admit in writing its inability to pay
      its debts generally as they become due, file a petition to take advantage
      of any applicable insolvency, bankruptcy or reorganization statute, make
      an assignment for the benefit of its creditors or voluntarily suspend
      payment of its obligations;

            (vii) the Master Servicer shall be dissolved, or shall dispose of
      all or substantially all of its assets; or consolidate with or merge into
      another entity or shall permit another entity to consolidate or merge into
      it, such that the resulting entity does not meet the criteria for a
      successor servicer, as specified in Section 6.02 hereof; or

            (viii) the Master Servicer and any Subservicer appointed by it
      becomes ineligible to service for both Fannie Mae and Freddie Mac, which
      ineligibility continues unremedied for a period of 90 days;

then, and in each and every such case, subject to applicable law, so long as an
Event of Default shall not have been remedied, either the Trustee or the holders
of Certificates evidencing in the aggregate not less than 66 2/3% of the
aggregate Voting Interest represented by all Certificates, by notice in writing
to the Master Servicer (and to the Trustee if given by the Certificateholders)
may terminate all of the rights and obligations of the Master Servicer under
this Agreement and in and to the Mortgage Loans, but without prejudice to any
rights which the Master Servicer may have to the aggregate Master Servicing Fees
due prior to the date of transfer of the Master Servicer's responsibilities
hereunder, reimbursement of expenses to the extent permitted by this Agreement,
Periodic Advances and other advances of its own funds. Upon receipt by the
Master Servicer of such written notice, all authority and power of the Master
Servicer under this Agreement, whether with respect to the Certificates or the
Mortgage Loans or otherwise, shall pass to and be vested in the Trustee pursuant
to and under this Section, subject to the provisions of Section 7.05; and,
without limitation, the Trustee is hereby authorized and empowered to execute
and deliver, on behalf of the Master Servicer, as attorney-in-fact or otherwise,
any and all documents and other instruments, and to do or accomplish all other
acts or things necessary or appropriate to effect the purposes of such notice of
termination, whether to complete the transfer and endorsement or assignment of
the Mortgage Loans and related documents or otherwise. The Master Servicer
agrees to cooperate with the Trustee in effecting the termination of the Master
Servicer's responsibilities and rights hereunder and shall promptly provide the
Trustee all documents and records reasonably requested by it to enable it to
assume the Master Servicer's functions hereunder and shall promptly also
transfer to the Trustee all amounts which then have been or should have been
deposited in the Certificate Account by the Master Servicer or which are
thereafter received by the Master Servicer with respect to the Mortgage Loans.

      Section 7.02 Other Remedies of Trustee.

      During the continuance of any Event of Default, so long as such Event of
Default shall not have been remedied, the Trustee, in addition to the rights
specified in Section 7.01, shall have the right, in its own name as trustee of
an express trust, to take all actions now or hereafter existing at law, in
equity or by statute to enforce its rights and remedies and to protect the
interests, and enforce the rights and remedies, of the Certificateholders
(including the institution and prosecution of all judicial, administrative and
other proceedings and the filing of proofs of claim and debt in connection
therewith). Except as otherwise expressly provided in this Agreement, no remedy
provided for by this Agreement shall be exclusive of any other remedy, and each
and every remedy shall be cumulative and in addition to any other remedy and no
delay or omission to exercise any right or remedy shall impair any such right or
remedy or shall be deemed to be a waiver of any Event of Default.

      Section 7.03 Directions by Certificateholders and Duties of Trustee During
Event of Default.

      During the continuance of any Event of Default, Holders of Certificates
evidencing in the aggregate not less than 25% of the aggregate Voting Interest
represented by all Certificates may direct the time, method and place of
conducting any proceeding for any remedy available to the Trustee, or exercising
any trust or power conferred upon the Trustee, under this Agreement; provided,
however, that the Trustee shall be under no obligation to pursue any such
remedy, or to exercise any of the rights or powers vested in it by this
agreement (including, without limitation, (i) the conducting or defending of any
administrative action or litigation hereunder or in relation hereto and (ii) the
terminating of the Master Servicer from its rights and duties as servicer
hereunder) at the request, order or direction of any of the Certificateholders,
unless such Certificateholders shall have offered to the Trustee reasonable
security or indemnity against the cost, expenses and liabilities which may be
incurred therein or thereby and, provided further, that, subject to the
provisions of Section 8.01, the Trustee shall have the right to decline to
follow any such direction if the Trustee, in accordance with an Opinion of
Counsel, determines that the action or proceeding so directed may not lawfully
be taken or if the Trustee in good faith determines that the action or
proceeding so directed would involve it in personal liability or be unjustly
prejudicial to the nonassenting Certificateholders.

      Section 7.04 Action upon Certain Failures of the Master Servicer and upon
Event of Default.

      In the event that the Trustee shall have knowledge of any failure of the
Master Servicer specified in Section 7.01(i), (ii) or (iii) which would become
an Event of Default upon the Master Servicer's failure to remedy the same after
notice, the Trustee may, but need not if the Trustee deems it not in the
Certificateholders' best interest, give notice thereof to the Master Servicer;
provided however that, without limiting any remedy as a result of such failure,
the Trustee shall be required to give notice thereof to the Master Servicer in
the case of the failure by the Master Servicer to observe or perform any of its
covenants under Sections 3.05, 3.11, 3.12, 6.02 or 6.06(b) of this Agreement.
For all purposes of this Agreement, in the absence of actual knowledge by a
Responsible Officer of the Trustee, the Trustee shall not be deemed to have
knowledge of any failure of the Master Servicer as specified in Section 7.01(i),
(ii) and (iii) or any Event of Default unless notified thereof in writing by the
Master Servicer or by a Certificateholder.

      Section 7.05 Trustee to Act; Appointment of Successor.

      When the Master Servicer receives notice of termination pursuant to
Section 7.01 or the Trustee receives the resignation of the Master Servicer
evidenced by an Opinion of Counsel pursuant to Section 6.04, the Trustee shall
be the successor in all respects to the Master Servicer in its capacity as
master servicer under this Agreement and the transactions set forth or provided
for herein and shall have the rights and powers and be subject to all the
responsibilities, duties and liabilities relating thereto placed on the Master
Servicer by the terms and provisions hereof and in its capacity as such
successor shall have the same limitation of liability herein granted to the
Master Servicer. In the event that the Trustee is succeeding to the Master
Servicer as the Master Servicer, as compensation therefor, the Trustee shall be
entitled to receive monthly such portion of the Master Servicing Fee, together
with such other master servicing compensation as is agreed to at such time by
the Trustee and the Master Servicer, but in no event more than 25% thereof until
the date of final cessation of the Master Servicer's master servicing activities
hereunder. Notwithstanding the above, the Trustee may, if it shall be unwilling
to so act, or shall, if it is unable to so act or to obtain a qualifying bid as
described below, appoint, or petition a court of competent jurisdiction to
appoint, any housing and home finance institution, bank or mortgage servicing
institution having a net worth of not less than $10,000,000 and meeting such
other standards for a successor master servicer as are set forth herein, as the
successor to the Master Servicer hereunder in the assumption of all or any part
of the responsibilities, duties or liabilities of the Master Servicer hereunder;
provided, however, that until such a successor master servicer is appointed and
has assumed the responsibilities, duties and liabilities of the Master Servicer
hereunder, the Trustee shall continue as the successor to the Master Servicer as
provided above. Upon cessation of the Master Servicer's master servicing
activities hereunder, the Trustee or any other successor master servicer shall
be entitled to compensation not exceed the compensation specified in Section
6.05 hereof, which amount shall include compensation for acting as paying agent.
In the event the Trustee is required to solicit bids as provided above, the
Trustee shall solicit, by public announcement, bids from housing and home
finance institutions, banks and mortgage servicing institutions meeting the
qualifications set forth in the preceding sentence for the purchase of the
master servicing functions. Such public announcement shall specify that the
successor master servicer shall be entitled to the full amount of the Master
Servicing Fee as compensation together with the other master servicing
compensation in the form of late reporting fees or otherwise as provided in
Section 6.05, which amount shall include compensation for acting as paying
agent. Within 30 days after any such public announcement, the Trustee shall
negotiate and effect the sale, transfer and assignment of the master servicing
rights and responsibilities hereunder to the qualified party submitting the
highest qualifying bid. The Trustee shall deduct all costs and expenses of any
public announcement and of any sale, transfer and assignment of the master
servicing rights and responsibilities hereunder from any sum received by the
Trustee from the successor to the Master Servicer in respect of such sale,
transfer and assignment. After such deductions, the remainder of such sum shall
be paid by the Trustee to the Master Servicer at the time of such sale, transfer
and assignment to the Master Servicer's successor. The Trustee and such
successor shall take such action, consistent with this Agreement, as shall be
necessary to effectuate any such succession. The Master Servicer agrees to
cooperate with the Trustee and any successor master servicer in effecting the
termination of the Master Servicer's servicing responsibilities and rights
hereunder and shall promptly provide the Trustee or such successor master
servicer, as applicable, all documents and records reasonably requested by it to
enable it to assume the Master Servicer's function hereunder and shall promptly
also transfer to the Trustee or such successor master servicer, as applicable,
all amounts which then have been or should have been deposited in the
Certificate Account by the Master Servicer or which are thereafter received by
the Master Servicer with respect to the Mortgage Loans. Neither the Trustee nor
any other successor master servicer shall be deemed to be in default hereunder
by reason of any failure to make, or any delay in making, any distribution
hereunder or any portion thereof caused by (i) the failure of the Master
Servicer to deliver, or any delay in delivering, cash, documents or records to
it, or (ii) restrictions imposed by any regulatory authority having jurisdiction
over the Master Servicer. Notwithstanding anything to the contrary contained in
Section 7.01 above or this Section 7.05, the Master Servicer shall retain all of
its rights and responsibilities hereunder, and no successor (including the
Trustee) shall succeed thereto, if the assumption thereof by such successor
would cause the rating assigned to any Certificates to be revoked, downgraded or
placed on credit review status (other than for possible upgrading) by any Rating
Agency and the retention thereof by the Master Servicer would avert such
revocation, downgrading or review.

      All costs associated with the appointment of a successor master servicer,
to the extent not deducted from any sum received by the Trustee from the
successor master servicer, shall be paid to the Person that incurred them by the
predecessor master servicer. Without limiting the predecessor master servicer's
obligation, if the predecessor master servicer fails to pay such costs, such
costs shall be reimbursed by the Trust.

      The predecessor Master Servicer and successor Master Servicer shall notify
the Depositor and Trustee of any such appointment at least two Business Days
prior to the effective date thereof and shall provide the Depositor and the
Trustee with all information required by the Depositor to comply with its
reporting obligation under Item 6.02 of Form 8-K not later than the effective
date of such appointment and the successor Master Servicer shall report such
event on Form 8-K within four business days of the occurrence of such event.

      Section 7.06 Notification to Certificateholders.

      Upon any termination of the Master Servicer or appointment of a successor
master servicer, in each case as provided herein, the Trustee shall give prompt
written notice thereof to Certificateholders at their respective addresses
appearing in the Certificate Register. The Trustee shall also, within 45 days
after the occurrence of any Event of Default known to the Trustee, give written
notice thereof to Certificateholders at their respective addresses appearing in
the Certificate Register, unless such Event of Default shall have been cured or
waived within said 45 day period.


                                  ARTICLE VIII

                             CONCERNING THE TRUSTEE

      Section 8.01 Duties of Trustee.

      The Trustee, prior to the occurrence of an Event of Default and after the
curing of all Events of Default which may have occurred, undertakes to perform
such duties and only such duties as are specifically set forth in this
Agreement. In case an Event of Default has occurred (which has not been cured),
the Trustee, subject to the provisions of Sections 7.01, 7.03, 7.04 and 7.05,
shall exercise such of the rights and powers vested in it by this Agreement, and
use the same degree of care and skill in its exercise as a prudent investor
would exercise or use under the circumstances in the conduct of such investor's
own affairs.

      The Trustee, upon receipt of all resolutions, certificates, statements,
opinions, reports, documents, orders or other instruments furnished to the
Trustee, which are specifically required to be furnished pursuant to any
provision of this Agreement, shall examine them to determine whether they are in
the form required by this Agreement; provided, however, that the Trustee shall
not be responsible for the accuracy or content of any certificate, statement,
instrument, report, notice or other document furnished by the Master Servicer or
the Servicers pursuant to Articles III, IV and IX.

      No provision of this Agreement shall be construed to relieve the Trustee
from liability for its own negligent action, its own negligent failure to act or
its own willful misconduct; provided, however, that:

            (i) Prior to the occurrence of an Event of Default and after the
      curing of all such Events of Default which may have occurred, the duties
      and obligations of the Trustee shall be determined solely by the express
      provisions of this Agreement, the Trustee shall not be liable except for
      the performance of such duties and obligations as are specifically set
      forth in this Agreement, no implied covenants or obligations shall be read
      into this Agreement against the Trustee and, in the absence of bad faith
      on the part of the Trustee, the Trustee may conclusively rely, as to the
      truth of the statements and the correctness of the opinions expressed
      therein, upon any certificates or opinions furnished to the Trustee, and
      conforming to the requirements of this Agreement;

            (ii) The Trustee shall not be personally liable with respect to any
      action taken, suffered or omitted to be taken by it in good faith in
      accordance with the direction of holders of Certificates which evidence in
      the aggregate not less than 25% of the Voting Interest represented by all
      Certificates relating to the time, method and place of conducting any
      proceeding for any remedy available to the Trustee, or exercising any
      trust or power conferred upon the Trustee, under this Agreement; and

            (iii) The Trustee shall not be liable for any error of judgment made
      in good faith by any of its Responsible Officers, unless it shall be
      proved that the Trustee or such Responsible Officer, as the case may be,
      was negligent in ascertaining the pertinent facts.

      None of the provisions contained in this Agreement shall require the
Trustee to expend or risk its own funds or otherwise incur personal financial
liability in the performance of any of its duties hereunder or in the exercise
of any of its rights or powers if there is reasonable ground for believing that
repayment of such funds or adequate indemnity against such risk or liability is
not reasonably assured to it.

      Section 8.02 Certain Matters Affecting the Trustee.

      Except as otherwise provided in Section 8.01:

            (i) The Trustee may request and rely and shall be protected in
      acting or refraining from acting upon any resolution, Officer's
      Certificate, certificate of auditors or any other certificate, statement,
      instrument, opinion, report, notice, request, consent, order, appraisal,
      bond or other paper or document believed by it to be genuine and to have
      been signed or presented by the proper party or parties and the manner of
      obtaining consents and evidencing the authorization of the execution
      thereof shall be subject to such reasonable regulations as the Trustee may
      prescribe;

            (ii) The Trustee may consult with counsel, and any written advice of
      such counsel or any Opinion of Counsel shall be full and complete
      authorization and protection in respect of any action taken or suffered or
      omitted by it hereunder in good faith and in accordance with such advice
      or Opinion of Counsel;

            (iii) The Trustee shall not be personally liable for any action
      taken, suffered or omitted by it in good faith and believed by it to be
      authorized or within the discretion or rights or powers conferred upon it
      by this Agreement;

            (iv) Subject to Section 7.04, the Trustee shall not be accountable,
      shall have no liability and makes no representation as to any acts or
      omissions hereunder of the Master Servicer until such time as the Trustee
      may be required to act as Master Servicer pursuant to Section 7.05 and
      thereupon only for the acts or omissions of the Trustee as successor
      Master Servicer; and

            (v) The Trustee may execute any of the trusts or powers hereunder or
      perform any duties hereunder either directly or by or through agents or
      attorneys.

      Section 8.03 Trustee Not Required to Make Investigation.

      Prior to the occurrence of an Event of Default hereunder and after the
curing of all Events of Default which may have occurred, the Trustee shall not
be bound to make any investigation into the facts or matters stated in any
resolution, certificate, statement, instrument, opinion, report, notice,
request, consent, order, appraisal, bond, Mortgage, Mortgage Note or other paper
or document (provided the same appears regular on its face), unless requested in
writing to do so by holders of Certificates evidencing in the aggregate not less
than 51% of the Voting Interest represented by all Certificates; provided,
however, that if the payment within a reasonable time to the Trustee of the
costs, expenses or liabilities likely to be incurred by it in the making of such
investigation is, in the opinion of the Trustee, not reasonably assured to the
Trustee by the security afforded to it by the terms of this Agreement, the
Trustee may require reasonable indemnity against such expense or liability as a
condition to so proceeding. The reasonable expense of every such investigation
shall be paid by the Master Servicer or, if paid by the Trustee shall be repaid
by the Master Servicer upon demand.

      Section 8.04 Trustee Not Liable for Certificates or Mortgage Loans.

      The recitals contained herein and in the Certificates shall be taken as
the statements of the Depositor, and the Trustee assumes no responsibility as to
the correctness of the same. The Trustee makes no representation for the
correctness of the same. The Trustee makes no representation as to the validity
or sufficiency of this Agreement or of the Certificates or of any Mortgage Loan
or related document. Subject to Section 2.04, the Trustee shall not be
accountable for the use or application by the Depositor of any of the
Certificates or of the proceeds of such Certificates, or for the use or
application of any funds paid to the Master Servicer in respect of the Mortgage
Loans deposited into the Certificate Account by the Master Servicer or, in its
capacity as trustee, for investment of any such amounts.

      Section 8.05 Trustee May Own Certificates.

      The Trustee, and any agent thereof, in its individual or any other
capacity, may become the owner or pledgee of Certificates with the same rights
it would have if it were not Trustee or such agent and may transact banking
and/or trust business with the Depositor, the Master Servicer or their
Affiliates.

      Section 8.06 The Master Servicer to Pay Fees and Expenses; Limitation on
Liability.

      The Master Servicer covenants and agrees to pay to the Trustee from time
to time, from its own funds, and the Trustee shall be entitled to receive,
reasonable compensation (which shall not be limited by any provision of law in
regard to the compensation of a trustee of an express trust) for all services
rendered by it in the execution of the trusts hereby created and in the exercise
and performance of any of the powers and duties hereunder of the Trustee.

      In addition, except as otherwise agreed upon in writing by the Master
Servicer and the Trustee, the Trust shall reimburse the Trustee for all
reasonable expenses, disbursements and advances incurred or made by the Trustee
in accordance with any of the provisions of this Agreement to the extent
permitted by Treasury Regulations Section 1.860G-1(b)(3), except for (i) any
such expense, disbursement or advance arising from the Trustee's gross
negligence, bad faith or willful misconduct and (ii) any routine ongoing
expenses incurred by the Trustee in the ordinary course of its duties as Trustee
hereunder or for any other expenses.

      The Trustee and any director, officer, employee or agent of the Trustee
shall be entitled to indemnification by the Trust Estate and held harmless
against any loss, liability or expense (including reasonable attorney's fees)
(a) incurred in connection with any claim or legal action relating to (i) this
Agreement, (ii) the Certificates, or (iii) the performance of any of the
Trustee's duties under this Agreement, unless the loss, liability or expense was
incurred by reason of willful misfeasance, bad faith or gross negligence in the
performance of any of the Trustee's duties under this Agreement and (b)
resulting from any tax or information return which was prepared by, or should
have been prepared by, the applicable Servicer or Master Servicer.

      Section 8.07 Eligibility Requirements.

      The Trustee hereunder shall at all times (i) be a corporation or
association having its principal office in a state and city acceptable to the
Depositor, organized and doing business under the laws of such state or the
United States of America, authorized under such laws to exercise corporate trust
powers, having a combined capital and surplus of at least $50,000,000, or shall
be a member of a bank holding system, the aggregate combined capital and surplus
of which is at least $50,000,000, provided that its separate capital and surplus
shall at all times be at least the amount specified in Section 310(a)(2) of the
Trust Indenture Act of 1939, (ii) be subject to supervision or examination by
federal or state authority and (iii) have a credit rating or be otherwise
acceptable to the Rating Agencies such that none of the Rating Agencies would
reduce their respective then current ratings of the Certificates (or have
provided such security from time to time as is sufficient to avoid such
reduction) as evidenced in writing by each Rating Agency. If such corporation or
association publishes reports of condition at least annually, pursuant to law or
to the requirements of the aforesaid supervising or examining authority, then
for the purposes of this Section the combined capital and surplus of such
corporation or association shall be deemed to be its combined capital and
surplus as set forth in its most recent report of condition so published. In
case at any time the Trustee shall cease to be eligible in accordance with the
provisions of this Section, the Trustee shall resign immediately in the manner
and with the effect specified in Section 8.08.

      Section 8.08 Resignation and Removal.

      The Trustee may at any time resign and be discharged from the trust hereby
created by giving written notice of resignation to the Master Servicer, such
resignation to be effective upon the appointment of a successor trustee. Upon
receiving such notice of resignation, the Master Servicer shall promptly appoint
a successor trustee by written instrument, in duplicate, one copy of which
instrument shall be delivered to the resigning entity and one copy to its
successor. If no successor trustee shall have been appointed and have accepted
appointment within 30 days after the giving of such notice of resignation, the
resigning Trustee may petition any court of competent jurisdiction for the
appointment of a successor trustee.

      If at any time the Trustee shall cease to be eligible in accordance with
the provisions of Section 8.07 and shall fail to resign after written request
for its resignation by the Master Servicer, or if at any time the Trustee shall
become incapable of acting, or an order for relief shall have been entered in
any bankruptcy or insolvency proceeding with respect to such entity, or a
receiver of such entity or of its property shall be appointed, or any public
officer shall take charge or control of the Trustee or of the property or
affairs of the Trustee for the purpose of rehabilitation, conversion or
liquidation, or the Master Servicer shall deem it necessary in order to change
the situs of the Trust Estate for state tax reasons, then the Master Servicer
shall remove the Trustee and appoint a successor trustee by written instrument,
in duplicate, one copy of which instrument shall be delivered to the Trustee so
removed and one copy to the successor trustee.

      In addition, if (a) the Trustee fails to comply with its obligations to
deliver any assessment of servicing compliance or registered public accounting
firm attestation reports required pursuant to Section 3.11 or (b) any Servicing
Function Participant engaged by the Trustee fails to comply with its obligations
to deliver any assessment of servicing compliance or registered public
accounting firm attestation reports, the Master Servicer, may, after
consultation with the Depositor, remove the Trustee and appoint a successor
trustee by written instrument, in duplicate, one copy of which instrument shall
be delivered to the Trustee so removed and one copy to the successor trustee.

      The Holders of Certificates evidencing in the aggregate not less than 51%
of the Voting Interests represented by all Certificates (except that any
Certificate registered in the name of the Depositor, the Master Servicer or any
affiliate thereof will not be taken into account in determining whether the
requisite Voting Interests has been obtained) may at any time remove the Trustee
and appoint a successor by written instrument or instruments, in triplicate,
signed by such holders or their attorneys-in-fact duly authorized, one complete
set of which instruments shall be delivered to the Master Servicer, one complete
set of which shall be delivered to the entity or entities so removed and one
complete set of which shall be delivered to the successor so appointed.

      Any resignation or removal of the Trustee and appointment of a successor
pursuant to any of the provisions of this Section shall become effective upon
acceptance of appointment by the successor as provided in Section 8.09.

      Section 8.09 Successor.

      Any successor trustee appointed as provided in Section 8.08 shall execute,
acknowledge and deliver to the Master Servicer and to its predecessor trustee an
instrument accepting such appointment hereunder, and thereupon the resignation
or removal of the predecessor trustee shall become effective, and such
successor, without any further act, deed or reconveyance, shall become fully
vested with all the rights, powers, duties and obligations of its predecessor
hereunder, with like effect as if originally named as trustee herein. The
predecessor trustee shall deliver to its successor all documents and statements
held by it hereunder, and the Depositor, the Master Servicer and the predecessor
entity shall execute and deliver such instruments and do such other things as
may reasonably be required for more fully and certainly vesting and confirming
in the successor trustee all such rights, powers, duties and obligations.

      All costs associated with the appointment of a successor trustee shall be
paid to the Person that incurred them by the predecessor trustee. Without
limiting the predecessor trustee's obligation, if the predecessor trustee fails
to pay such costs, such costs shall be reimbursed by the Trust; provided
however, that if the predecessor trustee has been terminated pursuant to the
third paragraph of Section 8.08, all reasonable expenses incurred in complying
with this Section 8.09 shall be reimbursed by the Trust to the Person that
incurred them.

      No successor shall accept appointment as provided in this Section unless
at the time of such acceptance such successor shall be eligible under the
provisions of Section 8.07.

      Upon acceptance of appointment by a successor as provided in this Section,
the successor trustee shall mail notice of the succession of such trustee
hereunder to all Holders of Certificates at their addresses as shown in the
Certificate Register.

      Section 8.10 Merger or Consolidation.

      Any Person into which the Trustee may be merged or converted or with which
it may be consolidated, to which it may sell or transfer its corporate trust
business and assets as a whole or substantially as a whole or any Person
resulting from any merger, sale, transfer, conversion or consolidation to which
the Trustee shall be a party, or any Person succeeding to the business of such
entity, shall be the successor of the Trustee hereunder; provided, however, that
(i) such Person shall be eligible under the provisions of Section 8.07, without
the execution or filing of any paper or any further act on the part of any of
the parties hereto, anything herein to the contrary notwithstanding, (ii) the
Trustee shall deliver an Opinion of Counsel to the Depositor and the Master
Servicer to the effect that such merger, consolidation, sale or transfer will
not subject either of the Upper-Tier REMIC or the Lower-Tier REMIC to federal,
state or local tax or cause either of the Upper-Tier REMIC or the Lower-Tier
REMIC to fail to qualify as a REMIC, which Opinion of Counsel shall be at the
sole expense of the Trustee and (iii) the Trustee and such successor or
surviving Person shall notify the Depositor and the Master Servicer of any such
merger, conversion or consolidation at least two Business Days prior to the
effective date thereof and shall provide the Depositor and the Master Servicer
with all information required by the Depositor to comply with its reporting
obligations under Item 6.02 of Form 8-K not later than the effective date of
such merger, conversion or consolidation and the Master Servicer shall report
such event on Form 8-K within four business days of the occurrence of such
event.

      Section 8.11 Authenticating Agent.

      The Trustee may appoint an Authenticating Agent, which shall be authorized
to act on behalf of the Trustee in authenticating Certificates. Wherever
reference is made in this Agreement to the authentication of Certificates by the
Trustee or the Trustee's countersignature, such reference shall be deemed to
include authentication on behalf of the Trustee by the Authenticating Agent and
a certificate of authentication executed on behalf of the Trustee by the
Authenticating Agent. The Authenticating Agent must be acceptable to the
Depositor and the Master Servicer and must be a corporation organized and doing
business under the laws of the United States of America or of any state, having
a principal office and place of business in a state and city acceptable to the
Depositor and the Master Servicer, having a combined capital and surplus of at
least $15,000,000, authorized under such laws to do a trust business and subject
to supervision or examination by federal or state authorities.

      Any corporation into which the Authenticating Agent may be merged or
converted or with which it may be consolidated, or any corporation resulting
from any merger, conversion or consolidation to which the Authenticating Agent
shall be a party, or any corporation succeeding to the corporate agency business
of the Authenticating Agent, shall be the Authenticating Agent without the
execution or filing of any paper or any further act on the part of the Trustee
or the Authenticating Agent.

      The Authenticating Agent may at any time resign by giving at least 30
days' advance written notice of resignation to the Trustee, the Depositor and
the Master Servicer. Except with respect to Wells Fargo Bank, for so long as
Wells Fargo Bank is acting as the Master Servicer, the Trustee may at any time
terminate the agency of the Authenticating Agent by giving written notice
thereof to the Authenticating Agent, the Depositor and the Master Servicer. Upon
receiving a notice of resignation or upon such a termination, or in case at any
time the Authenticating Agent shall cease to be eligible in accordance with the
provisions of this Section 8.11, the Trustee promptly shall appoint a successor
Authenticating Agent, which shall be acceptable to the Master Servicer, and
shall give written notice of such appointment to the Depositor, and shall mail
notice of such appointment to all Certificateholders. Any successor
Authenticating Agent upon acceptance of its appointment hereunder shall become
vested with all the rights, powers, duties and responsibilities of its
predecessor hereunder, with like effect as if originally named as Authenticating
Agent herein. No successor Authenticating Agent shall be appointed unless
eligible under the provisions of this Section 8.11.

      The Authenticating Agent shall have no responsibility or liability for any
action taken by it as such at the direction of the Trustee. Any reasonable
compensation paid to the Authenticating Agent shall be payable by the Master
Servicer.

      Section 8.12 Separate Trustees and Co-Trustees.

      The Trustee shall have the power from time to time to appoint one or more
persons or corporations to act either as co-trustees jointly with the Trustee,
or as separate trustees, for the purpose of holding title to, foreclosing or
otherwise taking action with respect to any Mortgage Loan outside the state
where the Trustee has its principal place of business, where such separate
trustee or co-trustee is necessary or advisable (or the Trustee is advised by
the Master Servicer that such separate trustee or co-trustee is necessary or
advisable) under the laws of any state in which a Mortgaged Property is located
or for the purpose of otherwise conforming to any legal requirement, restriction
or condition in any state in which a Mortgaged Property is located or in any
state in which any portion of the Trust Estate is located. The Master Servicer
shall advise the Trustee when, in its good faith opinion, a separate trustee or
co-trustee is necessary or advisable as aforesaid. The separate trustees or
co-trustees so appointed shall be trustees for the benefit of all of the
Certificateholders and shall have such powers, rights and remedies as shall be
specified in the instrument of appointment; provided, however, that no such
appointment shall, or shall be deemed to, constitute the appointee an agent of
the Trustee. The Depositor and the Master Servicer shall join in any such
appointment, but such joining shall not be necessary for the effectiveness of
such appointment.

      Every separate trustee and co-trustee shall, to the extent permitted by
law, be appointed and act subject to the following provisions and conditions:

            (i) all powers, duties, obligations and rights conferred upon the
      Trustee, in respect of the receipt, custody and payment of moneys shall be
      exercised solely by the Trustee;

            (ii) all other rights, powers, duties and obligations conferred or
      imposed upon the Trustee shall be conferred or imposed upon and exercised
      or performed by the Trustee and such separate trustee or co-trustee
      jointly, except to the extent that under any law of any jurisdiction in
      which any particular act or acts are to be performed (whether as Trustee
      hereunder or as successor to the Master Servicer hereunder) the Trustee
      shall be incompetent or unqualified to perform such act or acts, in which
      event such rights, powers, duties and obligations (including the holding
      of title to the Trust Estate or any portion thereof in any such
      jurisdiction) shall be exercised and performed by such separate trustee or
      co-trustee;

            (iii) no separate trustee or co-trustee hereunder shall be
      personally liable by reason of any act or omission of any other separate
      trustee or co-trustee hereunder; and

            (iv) the Trustee may at any time accept the resignation of or remove
      any separate trustee or co-trustee so appointed by it, if such resignation
      or removal does not violate the other terms of this Agreement.

      Any notice, request or other writing given to the Trustee shall be deemed
to have been given to each of the then separate trustees and co-trustees, as
effectively as if given to each of them. Every instrument appointing any
separate trustee, co-trustee, or custodian shall refer to this Agreement and the
conditions of this Article. Each separate trustee and co-trustee, upon its
acceptance of the trusts conferred, shall be vested with the estates or property
specified in its instrument of appointment, either jointly with the Trustee, or
separately, as may be provided therein, subject to all the provisions of this
Agreement, specifically including every provision of this Agreement relating to
the conduct of, affecting the liability of, or affording protection to, the
Trustee. Every such instrument shall be furnished to the Trustee.

      Any separate trustee, co-trustee, or custodian may, at any time,
constitute the Trustee, its agent or attorney-in-fact, with full power and
authority, to the extent not prohibited by law, to do any lawful act under or in
respect of this Agreement on its behalf and in its name. If any separate trustee
or co-trustee shall die, become incapable of acting, resign or be removed, all
of its estates, properties, rights, remedies and trusts shall vest in and be
exercised by the Trustee to the extent permitted by law, without the appointment
of a new or successor trustee.

      No separate trustee or co-trustee hereunder shall be required to meet the
terms of eligibility as a successor trustee under Section 8.07 hereunder and no
notice to Certificateholders of the appointment thereof shall be required under
Section 8.09 hereof.

      The Trustee agrees to instruct its co-trustees, if any, to the extent
necessary to fulfill such entity's obligations hereunder.

      The fees of any co-trustee whose appointment is necessary or advisable for
(i) conforming to any legal requirement, restriction or condition in any state
in which any Mortgaged Property or any portion of the Trust Estate is located,
will be paid by the Master Servicer, without reimbursement from the Trust and
(ii) any reason other than contemplated by clause (i), will be paid by the
Trustee, without reimbursement from the Trust. Expenses will be reimbursable to
the co-trustees to the extent, and in accordance with the standards, specified
in Section 8.06 hereof.

      Section 8.13 Tax Matters; Compliance with REMIC Provisions.

      (a) Each of the Trustee and the Master Servicer covenants and agrees that
it shall perform its duties hereunder in a manner consistent with the REMIC
Provisions and shall not knowingly take any action or fail to take any other
action that would (i) affect the determination of the Trust Estate's status as
two separate REMICs; or (ii) cause the imposition of any federal, state or local
income, prohibited transaction, contribution or other tax on any of the
Upper-Tier REMIC, the Lower-Tier REMIC or the Trust Estate. The Master Servicer,
or, in the case of any tax return or other action required by law to be
performed directly by the Trustee, the Trustee, shall (i) prepare or cause to be
prepared, timely cause to be signed by the Trustee and file or cause to be filed
annual federal and applicable state and local income tax returns for each of the
Upper-Tier REMIC and the Lower-Tier REMIC using a calendar year as the taxable
year and the accrual method of accounting; (ii) in the first such federal tax
return, make, or cause to be made, elections satisfying the requirements of the
REMIC Provisions, on behalf of the Trust Estate, to treat each of the Upper-Tier
REMIC and the Lower-Tier REMIC as a REMIC; (iii) prepare, execute and forward,
or cause to be prepared, executed and forwarded, to the Certificateholders all
information reports or tax returns required with respect to the Trust Estate, as
and when required to be provided to the Certificateholders, and to the Internal
Revenue Service and any other relevant governmental taxing authority in
accordance with the REMIC Provisions and any other applicable federal, state or
local laws, including without limitation information reports relating to
"original issue discount" and "market discount" as defined in the Code based
upon the issue prices, prepayment assumption and cash flows provided by the
Depositor to the Trustee and calculated on a monthly basis by using the issue
prices of the Certificates; (iv) make available information necessary for the
application of any tax imposed on transferors of residual interests to
"disqualified organizations" (as defined in the REMIC Provisions); (v) file Form
8811 and apply for an Employee Identification Number with a Form SS-4 or any
other permissible method and respond to inquiries by Certificateholders or their
nominees concerning information returns, reports or tax returns; (vi) maintain
(or cause to be maintained by the Servicers) such records relating to the
Upper-Tier REMIC and the Lower-Tier REMIC, including but not limited to the
income, expenses, individual Mortgage Loans (including REO Mortgage Loans),
other assets and liabilities of each REMIC, and the fair market value and
adjusted basis of the property of each REMIC determined at such intervals as may
be required by the Code, as may be necessary to prepare the foregoing returns or
information reports; (vii) exercise reasonable care not to allow the creation of
any "interests" in either of the Upper-Tier REMIC or the Lower-Tier REMIC within
the meaning of Code Section 860D(a)(2) other than the interests represented by
the Class I-A-1, Class I-A-2, Class I-A-3, Class I-A-4, Class I-A-5, Class
I-A-6, Class I-A-7, Class I-A-8, Class I-A-9, Class I-A-10, Class I-A-11, Class
I-A-12, Class I-A-13, Class I-A-14, Class I-A-PO, Class II-A-1, Class II-A-2,
Class II-A-3, Class II-A-PO, Class I-B-1, Class I-B-2, Class I-B-3, Class I-B-4,
Class I-B-5, Class I-B-6, Class II-B-1, Class II-B-2, Class II-B-3, Class
II-B-4, Class II-B-5 and Class II-B-6 Certificates and the Class I-A-R Interest,
and the interests in the Lower-Tier REMIC represented by the Class I-A-L1
Interest, Class I-A-L5 Interest, Class I-A-LPO Interest, Class I-A-LUR Interest,
Class II-A-L1 Interest, Class II-A-L2 Interest, Class II-A-L3 Interest, Class
II-A-LPO Interest, Class I-B-L1 Interest, Class I-B-L2 Interest, Class I-B-L3
Interest, Class I-B-L4 Interest, Class I-B-L5 Interest, Class I-B-L6 Interest,
Class II-B-L1 Interest, Class II-B-L2 Interest, Class II-B-L3 Interest, Class
II-B-L4 Interest, Class II-B-L5 Interest and Class II-B-L6 Interest, and the
Class I-A-LR Interest; (viii) exercise reasonable care not to allow the
occurrence of any "prohibited transactions" within the meaning of Code Section
860F(a), unless the Master Servicer shall have provided an Opinion of Counsel to
the Trustee that such occurrence would not (a) result in a taxable gain, (b)
otherwise subject any of the Upper-Tier REMIC, the Lower-Tier REMIC or the Trust
Estate to tax or (c) cause the Trust Estate to fail to qualify as two separate
REMICs; (ix) exercise reasonable care not to allow either of the Upper-Tier
REMIC or the Lower-Tier REMIC to receive income from the performance of services
or from assets not permitted under the REMIC Provisions to be held by a REMIC;
and (x) pay (on behalf of the Upper-Tier REMIC or the Lower-Tier REMIC) the
amount of any federal income tax, including, without limitation, prohibited
transaction taxes, taxes on net income from foreclosure property, and taxes on
certain contributions to a REMIC after the Startup Day, imposed on the
Upper-Tier REMIC or the Lower-Tier REMIC, as the case may be, when and as the
same shall be due and payable (but such obligation shall not prevent the Master
Servicer or any other appropriate Person from contesting any such tax in
appropriate proceedings and shall not prevent the Master Servicer from
withholding or depositing payment of such tax, if permitted by law, pending the
outcome of such proceedings). The Master Servicer shall be entitled to be
reimbursed pursuant to Section 3.02 for any taxes paid by it pursuant to clause
(x) of the preceding sentence, except to the extent that such taxes are imposed
as a result of the bad faith, willful misfeasance or gross negligence of the
Master Servicer in the performance of its obligations hereunder.

      In order to enable the Master Servicer or the Trustee, as the case may be,
to perform its duties as set forth above, the Depositor shall provide, or cause
to be provided, to the Master Servicer within ten days after the Closing Date
all information or data that the Master Servicer determines to be relevant for
tax purposes to the valuations and offering prices of the Certificates,
including, without limitation, the price, yield, prepayment assumption and
projected cash flows of each Class of Certificates and the Mortgage Loans in the
aggregate. Thereafter, the Depositor shall provide to the Master Servicer or the
Trustee, as the case may be, promptly upon request therefor, any such additional
information or data that the Master Servicer or the Trustee, as the case may be,
may from time to time request in order to enable the Master Servicer to perform
its duties as set forth above. The Depositor hereby indemnifies the Master
Servicer or the Trustee, as the case may be, for any losses, liabilities,
damages, claims or expenses of the Master Servicer or the Trustee arising from
any errors or miscalculations by the Master Servicer or the Trustee pursuant to
this Section that result from any failure of the Depositor to provide, or to
cause to be provided, accurate information or data to the Master Servicer or the
Trustee, as the case may be, on a timely basis. The Master Servicer hereby
indemnifies the Depositor and the Trustee for any losses, liabilities, damages,
claims or expenses of the Depositor or the Trustee arising from the Master
Servicer's willful misfeasance, bad faith or gross negligence in preparing any
of the federal, state and local tax returns of either REMIC as described above.
In the event that the Trustee prepares any of the federal, state and local tax
returns of either REMIC as described above, the Trustee hereby indemnifies the
Depositor and the Master Servicer for any losses, liabilities, damages, claims
or expenses of the Depositor or the Master Servicer arising from the Trustee's
willful misfeasance, bad faith or negligence in connection with such
preparation.

      (b) Notwithstanding anything in this Agreement to the contrary, each of
the Master Servicer and the Trustee shall pay from its own funds, without any
right of reimbursement therefor, the amount of any costs, liabilities and
expenses incurred by the Trust Estate (including, without limitation, any and
all federal, state or local taxes, including taxes imposed on "prohibited
transactions" within the meaning of the REMIC Provisions) if and to the extent
that such costs, liabilities and expenses arise from a failure of the Master
Servicer or the Trustee, respectively, to perform its obligations under this
Section 8.13.

      The Holder of the Class I-A-R Certificate is hereby designated as the "tax
matters person" for the Upper-Tier REMIC and the Lower-Tier REMIC within the
meaning of Treasury Regulations Section 1.860F- 4(d). The "tax matters person"
shall have the same duties with respect to the applicable REMIC as those of a
"tax matters partner" under Subchapter C of Chapter 63 of Subtitle F of the
Code. By its acceptance of the Class I-A-R Certificate, such Holder irrevocably
appoints the Master Servicer (and the Master Servicer hereby agrees to act) as
agent to perform all of the duties of the "tax matters person."

      (c) For federal tax return and information reporting, the right of the
Holders of the Class I-A-5 Certificates to receive payments under the Yield
Maintenance Agreement shall be assigned a value of zero.

      Section 8.14 Monthly Advances.

      In the event that Wells Fargo Bank in its capacity as Servicer fails to
make a Periodic Advance required to be made pursuant to the Wells Fargo Bank
Servicing Agreement on or before the Distribution Date, the Trustee shall make a
Periodic Advance as required by Section 3.03 hereof; provided, however, the
Trustee shall not be required to make such Periodic Advances if prohibited by
law or if it determines that such Periodic Advance would be a Nonrecoverable
Advance. With respect to those Periodic Advances which should have been made by
Wells Fargo Bank, the Trustee shall be entitled, pursuant to Section 3.02(a)(i),
(ii) or (v) hereof, to be reimbursed from the Certificate Account for Periodic
Advances and Nonrecoverable Advances made by it.


                                   ARTICLE IX

                                   TERMINATION

      Section 9.01 Termination upon Purchase by the Depositor or Liquidation of
All Mortgage Loans.

      Subject to Section 9.02, the respective obligations and responsibilities
of the parties to this Agreement created hereby (other than the obligation of
the Paying Agent to make certain payments after the Final Distribution Date to
Certificateholders and the obligation of the Master Servicer to send certain
notices as hereinafter set forth and the tax reporting obligations under
Sections 4.05 and 8.13 hereof) shall terminate upon the last action required to
be taken by the Paying Agent on the Final Distribution Date pursuant to this
Article IX following the earlier of (i) the purchase by the Depositor of all
Mortgage Loans and all property acquired in respect of any Mortgage Loan
remaining in the Trust Estate at a price equal to the sum of (x) 100% of the
unpaid principal balance of each Mortgage Loan (other than any REO Mortgage
Loan) as of the Final Distribution Date, (y) the fair market value of the
Mortgaged Property related to any REO Mortgage Loan, plus with respect to
clauses (x) and (y) any accrued and unpaid interest through the last day of the
month preceding the month of such purchase at the applicable Mortgage Interest
Rate less any Fixed Retained Yield on each Mortgage Loan (including any REO
Mortgage Loan) and (z) any Reimbursement Amount owed to the Trust pursuant to
Section 2.03 and (ii) the final payment or other liquidation (or any advance
with respect thereto) of the last Mortgage Loan remaining in the Trust Estate
(including for this purpose the discharge of any Mortgagor under a defaulted
Mortgage Loan on which a Servicer is not obligated to foreclose due to
environmental impairment) or the disposition of all property acquired upon
foreclosure or deed in lieu of foreclosure of any Mortgage Loan; provided,
however, that in no event shall the trust created hereby continue beyond the
expiration of 21 years from the death of the last survivor of the descendants of
Joseph P. Kennedy, the late ambassador of the United States to the Court of St.
James, living on the date hereof.

      The right of the Depositor to purchase all the assets of the Trust Estate
pursuant to clause (i) of the preceding paragraph is subject to Section 9.02 and
conditioned upon (A) the Pool Scheduled Principal Balance of the Mortgage Loans
as of the Final Distribution Date being less than the amount set forth in
Section 11.24 and (B) the sum of clause (i)(x) and (y) of the preceding
paragraph being less than or equal to the aggregate fair market value of the
Mortgage Loans (other than any REO Mortgage Loans) and the Mortgaged Properties
related to the REO Mortgage Loans; provided, however, that this clause (B) shall
not apply to any purchase by the Depositor if, at the time of the purchase, the
Depositor is no longer subject to regulation by the Office of the Comptroller of
the Currency, the FDIC, the Federal Reserve or the Office of Thrift Supervision.
Fair market value for purposes of this paragraph and the preceding paragraph
will be determined by the Master Servicer as of the close of business on the
third Business Day next preceding the date upon which notice of any termination
is furnished to Certificateholders pursuant to the third paragraph of this
Section 9.01. In the case of any purchase by the Depositor pursuant to said
clause (i) of the preceding paragraph, the Depositor shall give the Trustee, the
Paying Agent and the Master Servicer notice of its intent to purchase the assets
of the Trust by the fifth day of the month of the Final Distribution Date or
such later date as shall be acceptable to the Trustee and Master Servicer. The
Depositor or Master Servicer shall in such case provide to the Trustee the
confirmation of deposit of the purchase price required by Section 3.04 and the
Trustee or the Custodian shall, promptly following payment of the purchase price
and upon receipt from the Master Servicer of a Request for Release, release to
the Depositor the Owner Mortgage Loan Files and Retained Mortgage Loan Files, if
applicable, pertaining to the Mortgage Loans being purchased.

      Notice of any termination, specifying the Final Distribution Date (which
shall be a date that would otherwise be a Distribution Date) upon which the
Certificateholders may surrender their Certificates to the Paying Agent for
payment of the final distribution and cancellation, shall be given promptly by
the Paying Agent by letter to Certificateholders mailed not earlier than the
15th day of the month preceding the month of such final distribution and not
later than the twentieth day of the month of such final distribution specifying
(A) the Final Distribution Date upon which final payment of the Certificates
will be made upon presentation and surrender of Certificates at the Corporate
Trust Office of the Paying Agent therein designated, (B) the amount of any such
final payment and (C) that the Record Date otherwise applicable to such
Distribution Date is not applicable, payments being made (except in the case of
any Class A Certificate surrendered on a prior Distribution Date) pursuant to
Section 4.01 only upon presentation and surrender of the Certificates at the
Corporate Trust Office of the Paying Agent therein specified. If the Depositor
is exercising its right to purchase, the Depositor shall deposit in the
Certificate Account on or before the Final Distribution Date in immediately
available funds an amount equal to the purchase price for the assets of the
Trust Estate computed as above provided. Failure to give notice of termination
as described herein shall not entitle a Certificateholder to any interest beyond
the interest payable on the Final Distribution Date.

      Upon presentation and surrender of the Certificates, the Paying Agent
shall distribute to Certificateholders on the Final Distribution Date in
proportion to their respective Percentage Interests an amount equal to (i) as to
the Classes of Class A Certificates, the respective Principal Balance together
with any related Class A Unpaid Interest Shortfall and one month's interest in
an amount equal to the respective Interest Accrual Amount, (ii) as to the
Classes of Class B Certificates, the respective Principal Balance together with
any related Class B Unpaid Interest Shortfall and one month's interest in an
amount equal to the respective Interest Accrual Amount and (iii) as to the Class
I-A-R Certificate, the amounts, if any, which remain on deposit in the
Upper-Tier Certificate Account and the Certificate Account, respectively (other
than amounts retained to meet claims) after application pursuant to clauses (i)
and (ii) above and payment to the Master Servicer of any amounts it is entitled
as reimbursement or otherwise hereunder. Such amount shall be distributed in
respect of interest and principal in respect of the Uncertificated Lower-Tier
Interests in the manner specified in Section 4.01(a)(iii). Notwithstanding the
foregoing, if the price paid pursuant to clause (i) of the first paragraph of
this Section 9.01, after reimbursement to the Servicers, the Master Servicer and
the Trustee of any Periodic Advances, is insufficient to pay in full the amounts
set forth in clauses (i) and (ii) of this paragraph, then any shortfall in the
amount available for distribution to Certificateholders shall be allocated in
reduction of the amounts otherwise distributable on the Final Distribution Date
in the same manner as Realized Losses are allocated pursuant to Sections 4.02(a)
and (e) hereof. Such distribution on the Final Distribution Date shall be in
lieu of the distribution otherwise required to be made on such Distribution Date
in respect of each Class of Certificates.

      In the event that all of the Certificateholders shall not surrender their
Certificates for final payment and cancellation within three months following
the Final Distribution Date, the Paying Agent shall on such date cause all
funds, if any, in the Payment Account not distributed in final distribution to
Certificateholders to be withdrawn therefrom and credited to the remaining
Certificateholders by depositing such funds in a separate escrow account for the
benefit of such Certificateholders. The Paying Agent shall give a second written
notice to the remaining Certificateholders to surrender their Certificates for
cancellation and receive the final distribution with respect thereto. If within
three months after the second notice all the Certificates shall not have been
surrendered for cancellation, the Paying Agent may take appropriate steps, or
may appoint an agent to take appropriate steps, to contact the remaining
Certificateholders concerning surrender of their Certificates, and the cost
thereof shall be paid out of the funds on deposit in such escrow account.

      Section 9.02 Additional Termination Requirements.

      In the event of a termination of the Trust Estate upon the exercise by the
Depositor of its purchase option as provided in Section 9.01, the Trust Estate
shall be terminated in accordance with the following additional requirements,
unless the Trustee and the Master Servicer have received an Opinion of Counsel
to the effect that any other manner of termination (i) will constitute a
"qualified liquidation" of the Trust Estate within the meaning of Code Section
860F(a)(4)(A) and (ii) will not subject either of the Upper-Tier REMIC or the
Lower-Tier REMIC to federal tax or cause the Trust Estate to fail to qualify as
two separate REMICs at any time that any Certificates are outstanding:

            (i) The notice given by the Paying Agent under Section 9.01 shall
      provide that such notice constitutes the adoption of a plan of complete
      liquidation of the Upper-Tier REMIC and the Lower-Tier REMIC as of the
      date of such notice (or, if earlier, the date on which the first such
      notice is mailed to Certificateholders). The Master Servicer shall also
      specify such date in a statement attached to the final tax returns of the
      Upper-Tier REMIC and the Lower-Tier REMIC; and

            (ii) At or after the time of adoption of such a plan of complete
      liquidation and at or prior to the Final Distribution Date, the Trustee
      shall sell all of the assets of the Trust Estate to the Depositor for cash
      at the purchase price specified in Section 9.01 and the Paying Agent shall
      distribute such cash within 90 days of such adoption in the manner
      specified in Section 9.01.


                                   ARTICLE X

                            MISCELLANEOUS PROVISIONS

      Section 10.01 Amendment.

      (a) This Agreement or the Custodial Agreement may be amended from time to
time by the Depositor, the Master Servicer and the Trustee without the consent
of any of the Certificateholders, (i) to cure any ambiguity or mistake, (ii) to
correct or supplement any provisions herein or therein which may be inconsistent
with any other provisions herein or therein or in the related Prospectus, (iii)
to modify, eliminate or add to any of its provisions to such extent as shall be
necessary to maintain the qualification of the Trust Estate as two separate
REMICs at all times that any Certificates are outstanding or to avoid or
minimize the risk of the imposition of any federal tax on the Trust Estate, the
Upper-Tier REMIC or the Lower-Tier REMIC pursuant to the Code that would be a
claim against the Trust Estate, provided that (a) the Trustee has received an
Opinion of Counsel to the effect that such action is necessary or desirable to
maintain such qualification or to avoid or minimize the risk of the imposition
of any such tax and (b) such action shall not, as evidenced by such Opinion of
Counsel, adversely affect in any material respect the interests of any
Certificateholder, (iv) to conform the obligations of the parties under this
Agreement, or to add obligations of the parties to this Agreement, if necessary,
to comply with the requirements of Regulation AB, (v) to change the timing
and/or nature of deposits into the Upper-Tier Certificate Account and the
Certificate Account provided that such change shall not, as evidenced by an
Opinion of Counsel, adversely affect in any material respect the interests of
any Certificateholder, (vi) to modify, eliminate or add to the provisions of
Section 5.02 or any other provisions hereof restricting transfer of the
Certificates, provided that the Depositor for purposes of Section 5.02 has
determined in its sole discretion that any such modifications to this Agreement
will neither adversely affect the rating on the Certificates nor give rise to a
risk that either of the Upper-Tier REMIC or the Lower-Tier REMIC or any of the
Certificateholders will be subject to a tax caused by a transfer to a
non-permitted transferee, (vii) to make certain provisions with respect to the
denominations of, and the manner of payments on, certain Classes of Certificates
initially retained by the Depositor or an affiliate of the Depositor and (viii)
to make any other provisions with respect to matters or questions arising under
this Agreement or such Custodial Agreement which shall not be materially
inconsistent with the provisions of this Agreement, provided that such action
shall not, as evidenced by an Opinion of Counsel, adversely affect in any
material respect the interests of any Certificateholder. Notwithstanding the
foregoing, any amendment pursuant to clause (v) or (viii) shall not be deemed to
adversely affect in any material respect the interest of Certificateholders and
no Opinion of Counsel to that effect shall be required if the person requesting
the amendment instead obtains a letter from each Rating Agency stating that the
amendment would not result in the downgrading or withdrawal of the respective
ratings then assigned to the Certificates.

      This Agreement or the Custodial Agreement may also be amended from time to
time by the Depositor, the Master Servicer and the Trustee with the consent of
the Holders of Certificates evidencing in the aggregate not less than 66-2/3% of
the aggregate Voting Interests of each Class of Certificates affected thereby,
for the purpose of adding any provisions to or changing in any manner or
eliminating any of the provisions of this Agreement or such Custodial Agreement
or of modifying in any manner the rights of the Holders of Certificates of such
Class; provided, however, that no such amendment shall (i) reduce in any manner
the amount of, or delay the timing of, payments received on Mortgage Loans which
are required to be distributed on any Certificate without the consent of the
Holder of such Certificate, (ii) adversely affect in any material respect the
interest of the Holders of Certificates of any Class in a manner other than as
described in clause (i) hereof without the consent of Holders of Certificates of
such Class evidencing, as to such Class, Voting Interests aggregating not less
than 66-2/3% or (iii) reduce the aforesaid percentage of Certificates of any
Class the Holders of which are required to consent to any such amendment,
without the consent of the Holders of all Certificates of such Class then
outstanding.

      Notwithstanding any contrary provision of this Agreement, the Trustee
shall not consent to any amendment to this Agreement unless it shall have first
received an Opinion of Counsel to the effect that such amendment will not
subject either of the Upper-Tier REMIC or the Lower-Tier REMIC to tax or cause
either of the Upper-Tier REMIC or the Lower-Tier REMIC to fail to qualify as a
REMIC at any time that any Certificates are outstanding.

      Promptly after the execution of any amendment requiring the consent of
Certificateholders, the Trustee shall furnish written notification of the
substance of such amendment to each Certificateholder.

      It shall not be necessary for the consent of Certificateholders under this
Section 10.01(a) to approve the particular form of any proposed amendment, but
it shall be sufficient if such consent shall approve the substance thereof. The
manner of obtaining such consents and of evidencing the authorization of the
execution thereof by Certificateholders shall be subject to such reasonable
regulations as the Trustee may prescribe.

      (b) Notwithstanding any contrary provision of this Agreement, if any of
the Mortgage Loans are Type 2 Mortgage Loans, as indicated on the Mortgage Loan
Schedule, the Master Servicer may, from time to time, amend Schedule I hereto
without the consent of any Certificateholder or the Trustee; provided, however,
(i) that such amendment does not conflict with any provisions of the related
Servicing Agreement, (ii) that the related Servicing Agreement provides for the
remittance of each type of Unscheduled Principal Receipts received by such
Servicer during the Applicable Unscheduled Principal Receipt Period (as so
amended) related to each Distribution Date to the Master Servicer no later than
the 24th day of the month in which such Distribution Date occurs and (iii) that
such amendment is for the purpose of changing the Applicable Unscheduled
Principal Receipt Period for Type 2 Mortgage Loans to a Mid-Month Receipt Period
with respect to all Unscheduled Principal Receipts.

      Section 10.02 Recordation of Agreement.

      This Agreement (or an abstract hereof, if acceptable to the applicable
recording office) is subject to recordation in all appropriate public offices
for real property records in all the towns or other comparable jurisdictions in
which any or all of the Mortgaged Properties are situated, and in any other
appropriate public office or elsewhere, such recordation to be effected by the
Master Servicer and at its expense on direction by the Trustee, but only upon
direction accompanied by an Opinion of Counsel to the effect that such
recordation materially and beneficially affects the interests of the
Certificateholders.

      For the purpose of facilitating the recordation of this Agreement as
herein provided and for other purposes, this Agreement may be executed
simultaneously in any number of counterparts, each of which counterparts shall
be deemed to be an original, and such counterparts shall constitute but one and
the same instrument.

      Section 10.03 Limitation on Rights of Certificateholders.

      The death or incapacity of any Certificateholder shall not operate to
terminate this Agreement or the Trust Estate, nor entitle such
Certificateholder's legal representatives or heirs to claim an accounting or
take any action or proceeding in any court for a partition or winding up of the
Trust Estate, nor otherwise affect the rights, obligations and liabilities of
the parties hereto or any of them.

      Except as otherwise expressly provided herein, no Certificateholder,
solely by virtue of its status as a Certificateholder, shall have any right to
vote or in any manner otherwise control the operation and management of the
Trust Estate, or the obligations of the parties hereto, nor shall anything
herein set forth, or contained in the terms of the Certificates, be construed so
as to constitute the Certificateholders from time to time as partners or members
of an association, nor shall any Certificateholder be under any liability to any
third person by reason of any action taken by the parties to this Agreement
pursuant to any provision hereof.

      No Certificateholder, solely by virtue of its status as Certificateholder,
shall have any right by virtue or by availing of any provision of this Agreement
to institute any suit, action or proceeding in equity or at law upon or under or
with respect to this Agreement, unless such Holder previously shall have given
to the Trustee a written notice of default and of the continuance thereof, as
hereinbefore provided, and unless the Holders of Certificates evidencing not
less than 25% of the Voting Interest represented by all Certificates shall have
made written request upon the Trustee to institute such action, suit or
proceeding in its own name as Trustee hereunder and shall have offered to the
Trustee such reasonable indemnity as it may require against the cost, expenses
and liabilities to be incurred therein or thereby, and the Trustee, for 60 days
after its receipt of such notice, request and offer of indemnity, shall have
neglected or refused to institute any such action, suit or proceeding; it being
understood and intended, and being expressly covenanted by each
Certificateholder with every other Certificateholder and the Trustee, that no
one or more Holders of Certificates shall have any right in any manner whatever
by virtue or by availing of any provision of this Agreement to affect, disturb
or prejudice the rights of the Holders of any other of such Certificates, or to
obtain or seek to obtain priority over or preference to any other such Holder,
or to enforce any right under this Agreement, except in the manner herein
provided and for the benefit of all Certificateholders. For the protection and
enforcement of the provisions of this Section, each and every Certificateholder
and the Trustee shall be entitled to such relief as can be given either at law
or in equity.

      Section 10.04 Governing Law; Jurisdiction.

      This Agreement shall be construed in accordance with the laws of the State
of New York (without regard to conflicts of laws principles), and the
obligations, rights and remedies of the parties hereunder shall be determined in
accordance with such laws.

      Section 10.05 Notices.

      Unless otherwise provided in this Agreement, all demands, notices and
communications hereunder shall be in writing and shall be deemed to have been
duly given if personally delivered at or mailed by certified or registered mail,
return receipt requested or by facsimile (i) in the case of the Depositor, to
Wells Fargo Asset Securities Corporation, 7430 New Technology Way, Frederick,
Maryland 21703, Attention: Vice President, Structured Finance or such other
address as may hereafter be furnished to the Master Servicer and the Trustee in
writing by the Depositor, (ii) in the case of the Master Servicer, to Wells
Fargo Bank, N.A., 9062 Old Annapolis Road, Columbia, Maryland 21045-1951,
Attention: Corporate Trust Services- WFMBS 2006-4; facsimile: (410) 715-2380 or
such other address as may hereafter be furnished to the Depositor and the
Trustee in writing by the Master Servicer and (iii) in the case of the Trustee
or the Paying Agent, to the Corporate Trust Office, or such other address as may
hereafter be furnished to the Depositor and the Master Servicer in writing by
the Trustee or the Paying Agent. Any notice required or permitted to be mailed
to a Certificateholder shall be given by first class mail, postage prepaid, at
the address of such Holder as shown in the Certificate Register. Any notice
mailed or transmitted within the time prescribed in this Agreement shall be
conclusively presumed to have been duly given, whether or not the addressee
receives such notice; provided, however, that any demand, notice or
communication to or upon the Depositor, the Master Servicer or the Trustee shall
not be effective until received.

      For all purposes of this Agreement, in the absence of actual knowledge by
an officer of the Master Servicer, the Master Servicer shall not be deemed to
have knowledge of any act or failure to act of any Servicer unless notified
thereof in writing by the Trustee, the Servicer or a Certificateholder.

      Section 10.06 Severability of Provisions.

      If any one or more of the covenants, agreements, provisions or terms of
this Agreement shall be for any reason whatsoever held invalid, then such
covenants, agreements, provisions or terms shall be deemed severable from the
remaining covenants, agreements, provisions or terms of this Agreement and shall
in no way affect the validity or enforceability of the other provisions of this
Agreement or of the Certificates or the rights of the Holders thereof.

      Section 10.07 Special Notices to Rating Agencies.

      (a) The Trustee shall give prompt notice to each Rating Agency of the
occurrence of any of the following events of which a Responsible Officer has
notice:

            (i) any amendment to this Agreement pursuant to Section 10.01(a);

            (ii) any assignment by the Master Servicer of its rights and
      delegation of its duties pursuant to Section 6.06;

            (iii) any resignation of the Master Servicer pursuant to Section
      6.04;

            (iv) the occurrence of any of the Events of Default described in
      Section 7.01;

            (v) any notice of termination given to the Master Servicer pursuant
      to Section 7.01; or

            (vi) the appointment of any successor to the Master Servicer
      pursuant to Section 7.05.

      (b) The Paying Agent shall give prompt notice to each Rating Agency of any
sale or transfer of the Class B Certificates pursuant to Section 5.02 to an
affiliate of the Depositor.

      (c) The Paying Agent shall give prompt notice to each Rating Agency of the
making of a final payment pursuant to Section 9.01.

      (d) The Master Servicer shall give prompt notice to each Rating Agency of
the occurrence of any of the following events:

            (i) the resignation of the Custodian or the appointment of a
      successor Custodian pursuant to the Custodial Agreement;

            (ii) the resignation or removal of the Trustee pursuant to Section
      8.08;

            (iii) the appointment of a successor trustee pursuant to Section
      8.09; or

            (iv) the sale, transfer or other disposition in a single transaction
      of 50% or more of the equity interests in the Master Servicer.

      (e) The Master Servicer shall deliver to each Rating Agency or otherwise
make available to each Rating Agency in a format acceptable to each Rating
Agency:

            (i) reports prepared pursuant to Section 3.05 and 3.11; and

            (ii) the Distribution Date Statements.

      Section 10.08 Covenant of Depositor.

      The Depositor shall not amend Article Third of its Certificate of
Incorporation without the prior written consent of each Rating Agency rating the
Certificates.

      Section 10.09 Recharacterization.

      The Parties intend the conveyance by the Depositor to the Trustee of all
of its right, title and interest in and to the Trust Estate pursuant to this
Agreement to constitute a purchase and sale and not a loan. Notwithstanding the
foregoing, to the extent that such conveyance is held not to constitute a sale
under applicable law, it is intended that this Agreement shall constitute a
security agreement under applicable law and that the Depositor shall be deemed
to have granted to the Trustee a first priority security interest in all of the
Depositor's right, title and interest in and to the Trust Estate. The Master
Servicer shall take all actions, including, without limitation, filing any
Uniform Commercial Code continuation statements, as shall be necessary to
perfect or maintain the perfection of such security interest.

      Section 10.10 Regulation AB Compliance; Intent of Parties; Reasonableness.
The parties hereto acknowledge that interpretations of the requirements of
Regulation AB may change over time, whether due to interpretive guidance
provided by the Commission or its staff, consensus among participants in the
asset-backed securities markets, advice of counsel, or otherwise, and agree to
comply with requests made by the Depositor or the Master Servicer in good faith
for delivery of information under these provisions on the basis of evolving
interpretations of Regulation AB. In connection with the Trust, the parties
hereto shall cooperate fully with the Master Servicer and the Depositor to
deliver to the Master Servicer and/or the Depositor, any and all statements,
reports, certifications, records and any other information available to such
party and reasonably necessary in the good faith determination of the Depositor
or the Master Servicer to permit the Depositor or the Master Servicer to comply
with the provisions of Regulation AB, together with such disclosures reasonably
believed by the Depositor or the Master Servicer to be necessary in order to
effect such compliance.


<PAGE>

                                   ARTICLE XI

                             TERMS FOR CERTIFICATES

      Section 11.01 Cut-Off Date.

            The Cut-Off Date for the Certificates is March 1, 2006.

      Section 11.02 Cut-Off Date Aggregate Principal Balance.

            The Cut-Off Date Aggregate Principal Balance is $953,944,126.59.

      Section 11.03 Original Group I-A Percentage.

            The Original Group I-A Percentage is 95.73736466%.

      Section 11.04 Original Group II-A Percentage.

            The Original Group II-A Percentage is 95.93661283%.

      Section 11.05 Original Principal Balances of the Classes of Class A
Certificates.

            As to the following Classes of Class A Certificates, the Principal
Balance or Notional Amount of such Class as of the Cut-Off Date, as follows:

                                                 Original
                                           Principal Balance or
                      Class                  Notional Amount
                      -----                  ---------------

              Class I-A-1                      $295,387,000.00
              Class I-A-2                       $29,940,000.00
              Class I-A-3                       $15,000,000.00
              Class I-A-4                          $625,000.00
              Class I-A-5                       $68,000,000.00
              Class I-A-6                       $68,000,000.00
              Class I-A-7                        $2,103,000.00
              Class I-A-8                       $63,093,000.00
              Class I-A-9                        $7,010,000.00
              Class I-A-10                       $2,304,000.00
              Class I-A-11                      $15,835,000.00
              Class I-A-12                      $55,000,000.00
              Class I-A-13                       $5,360,000.00
              Class I-A-14                      $16,500,000.00
              Class I-A-R                              $100.00
              Class I-A-PO                       $1,782,198.00
              Class II-A-1                     $157,087,000.00
              Class II-A-2                     $157,087,000.00
              Class II-A-3                      $20,846,000.00
              Class II-A-PO                      $1,142,115.00

      Section 11.06 Original Notional Amount.

      Section 11.06(a) Original Class I-A-6 Notional Amount.

            The Original Class I-A-6 Notional Amount is $68,000,000.00.\

      Section 11.07 Original Group I-A and Group II-A Non-PO Principal Balances.

            (a) Original Group I-A Non-PO Principal Balance.

            The Original Group I-A Non-PO Principal Balance is $576,157,100.00.

            (b) Original Group II-A Non-PO Principal Balance.

            The Original Group II-A Non-PO Principal Balance is $335,020,000.00.

      Section 11.08 Original Subordinated Percentage.

            (a) Original Group I Subordinated Percentage.

            The Original Group I Subordinated Percentage is 4.26263534%.

            (b) Original Group II Subordinated Percentage.

            The Original Group II Subordinated Percentage is 4.06338717%.

      Section 11.09 Original Group I Subordinated Principal Balance.

            The Original Group I Subordinated Principal Balance is
      $25,652,968.65.

      Section 11.10 Original Group II Subordinated Principal Balance.

            The Original Group II Subordinated Principal Balance is
      $14,189,743.93.

      Section 11.11 Original Principal Balances of the Classes of Class B
Certificates.

      As to the following Classes of Class B Certificate, the Principal Balance
of such Class as of the Cut-Off Date, is as follows:

                                             Original
                        Class            Principal Balance
                        -----            -----------------
                      Class I-B-1              $16,900,000.00
                      Class I-B-2               $3,320,000.00
                      Class I-B-3               $2,113,000.00
                      Class I-B-4               $1,207,000.00
                      Class I-B-5                 $905,000.00
                      Class I-B-6               $1,207,968.65
                     Class II-B-1               $8,584,000.00
                     Class II-B-2               $2,102,000.00
                     Class II-B-3               $1,401,000.00
                     Class II-B-4                 $701,000.00
                     Class II-B-5                 $701,000.00
                     Class II-B-6                 $700,743.93

      Section 11.12 Original Class I-B-1 and Class II-B-1 Fractional Interest.

            (a) Original Class I-B-1 Fractional Interest.

            The Original Class I-B-1 Fractional Interest is 1.45444038%.

            (b) Original Class II-B-1 Fractional Interest.

            The Original Class II-B-1 Fractional Interest is 1.60526561%.

      Section 11.13 Original Class I-B-2 and Class II-B-2 Fractional Interest.

            (a) Original Class I-B-2 Fractional Interest.

            The Original Class I-B-2 Fractional Interest is 0.90277131%.

            (b) Original Class II-B-2 Fractional Interest.

            The Original Class II-B-2 Fractional Interest is 1.00333509%.

      Section 11.14 Original Class I-B-3 and Class II-B-3 Fractional Interest.

            (a) Original Class I-B-3 Fractional Interest.

            The Original Class I-B-3 Fractional Interest is 0.55166385%.

            (b) Original Class II-B-3 Fractional Interest.

            The Original Class II-B-3 Fractional Interest is 0.60214354%.

      Section 11.15 Original Class I-B-4 and Class II-B-4 Fractional Interest.

            (a) Original Class I-B-4 Fractional Interest.

            The Original Class I-B-4 Fractional Interest is 0.35110224%.

            (b) Original Class II-B-4 Fractional Interest.

            The Original Class II-B-4 Fractional Interest is 0.40140458%.

      Section 11.16 Original Class I-B-5 and Class II-B-5 Fractional Interest.

            (a) Original Class I-B-5 Fractional Interest.

            The Original Class I-B-5 Fractional Interest is 0.20072257%.

            (b) Original Class II-B-5 Fractional Interest.

            The Original Class II-B-5 Fractional Interest is 0.20066562%.

      Section 11.17 Original Group I Class I-B-1 and Group II Class II-B-1
Percentages.

            (a) Original Group I Class I-B-1 Percentage.

            The Original Group I Class I-B-1 Percentage is 2.80819496%.

            (b) Original Group II Class II-B-1 Percentage.

            The Original Group II Class II-B-1 Percentage is 2.45812156%.

      Section 11.18 Original Group I Class I-B-2 and Group II Class II-B-2
Percentages.

            (a) Original Group I Class I-B-2 Percentage.

            The Original Group I Class I-B-2 Percentage is 0.55166907%.

            (b) Original Group II Class II-B-2 Percentage.

            The Original Group II Class II-B-2 Percentage is 0.60193051%.

      Section 11.19 Original Group I Class I-B-3 and Group II Class II-B-3
Percentages.

            (a) Original Group I Class I-B-3 Percentage.

            The Original Group I Class I-B-3 Percentage is 0.35110745%.

            (b) Original Group II Class II-B-3 Percentage.

            The Original Group II Class II-B-3 Percentage is 0.40119155%.

      Section 11.20 Original Group I Class I-B-4 and Group II Class II-B-4
Percentages.

            (a) Original Group I Class I-B-4 Percentage.

            The Original Group I Class I-B-4 Percentage is 0.20056162%.

            (b) Original Group II Class II-B-4 Percentage.

            The Original Group II Class II-B-4 Percentage is 0.20073896%.

      Section 11.21 Original Group I Class I-B-5 and Group II Class II-B-5
Percentages.

            (a) Original Group I Class I-B-5 Percentage.

            The Original Group I Class I-B-5 Percentage is 0.15037967%.

            (b) Original Group II Class II-B-5 Percentage.

            The Original Group II Class II-B-5 Percentage is 0.20073896%.

      Section 11.22 Original Group I Class I-B-6 and Group II Class II-B-6
Percentages.

            (a) Original Group I Class I-B-6 Percentage.

            The Original Group I Class I-B-6 Percentage is 0.20072257%.

            (b) Original Group II Class II-B-6 Percentage.

            The Original Group II Class II-B-6 Percentage is 0.20066563%.

      Section 11.23 Closing Date.

            The Closing Date is March 30, 2006.

      Section 11.24 Right to Purchase.

      The right of the Depositor to purchase all of the Mortgage Loans pursuant
to Section 9.01 hereof shall be conditioned upon the aggregate Scheduled
Principal Balance of the Mortgage Loans being less than $95,394,412.66 (10% of
the Cut-Off Date Aggregate Principal Balance) at the time of any such purchase.

      Section 11.25 Wire Transfer Eligibility.

      With respect to the Class A Certificates (other than the Class I-A-6 and
Class I-A-R Certificates) and the Class B Certificates, the minimum Denomination
eligible for wire transfer on each Distribution Date is $100,000. With respect
to the Class I-A-6 Certificates, the minimum Denomination eligible for wire
transfer on each Distribution Date is 34%. The Class I-A-R Certificate is not
eligible for wire transfer.

      Section 11.26 Single Certificate.

      A Single Certificate for the Class A Certificates (other than the Class
I-A-4, Class I-A-6, Class I-A-7, Class I-A-13, Class I-A-14, Class I-A-R, Class
I-A-PO, Class II-A-3 and Class II-A-PO Certificates) represents a $25,000
Denomination. A Single Certificate for the Class I-A-4, Class I-A-7, Class
I-A-13, Class I-A-PO, Class II-A-3, Class II-A-PO, Class I-B-1, Class I-B-2,
Class I-B-3, Class II-B-1, Class II-B-2 and Class II-B-3 Certificates represents
a $100,000 Denomination. A Single Certificate for the Class I-A-6 Certificates
represents a $22,667,000 Denomination. A Single Certificate for the Class I-A-14
Certificates represents a $1,000 Denomination. A Single Certificate for the
Class I-A-R Certificate represents a $100 Denomination. A Single Certificate for
the Class I-B-4, Class I-B-5, Class I-B-6, Class II-B-4, Class II-B-5 and Class
II-B-6 Certificates represents a $250,000 Denomination.

      Section 11.27 Servicing Fee Rate.

      The rate used to calculate the Servicing Fee is equal to such rate as is
set forth on the Mortgage Loan Schedule with respect to a Mortgage Loan.

      Section 11.28 Master Servicing Fee Rate.

      The rate used to calculate the Master Servicing Fee for each Mortgage Loan
shall be 0.010% per annum.


<PAGE>

      IN WITNESS WHEREOF, the Depositor, the Master Servicer and the Trustee
have caused their names to be signed hereto by their respective officers
thereunto duly authorized, all as of the day and year first above written.

                                       WELLS FARGO ASSET SECURITIES
                                          CORPORATION
                                            as Depositor

                                       By:    /s/ Bradley A. Davis
                                            -----------------------
                                            Name:  Bradley A. Davis
                                            Title: Vice President


                                       WELLS FARGO BANK, N.A.
                                            as Master Servicer

                                       By:    /s/ Jennifer L. Richardson
                                            -----------------------------
                                            Name:  Jennifer L. Richardson
                                            Title: Assistant Vice President


                                       U.S. BANK NATIONAL ASSOCIATION as Trustee

                                       By:    /s/ Melissa A. Rosal
                                            ----------------------
                                            Name: Melissa A. Rosal
                                            Title: Vice President


<PAGE>

STATE OF MARYLAND       )
                        ss.:
COUNTY OF FREDERICK     )

      On this 30th day of March, 2006, before me, a notary public in and for the
State of Maryland, personally appeared Bradley A. Davis, known to me who, being
by me duly sworn, did depose and say that he resides at Cooksville, Maryland;
that he is a Vice President of Wells Fargo Asset Securities Corporation, a
Delaware corporation, one of the parties that executed the foregoing instrument;
and that he signed his name thereto by order of the Board of Directors of said
corporation.

-------------------------
Notary Public

[NOTARIAL SEAL]


<PAGE>

STATE OF MARYLAND       )
                        ss.:
COUNTY OF HOWARD        )


      On this 30th day of March, 2006, before me, a notary public in and for the
State of Maryland, personally appeared Jennifer L. Richardson, known to me who,
being by me duly sworn, did depose and say that she resides in Riva, Maryland;
that she is an Assistant Vice President of Wells Fargo Bank, N.A., a national
banking association, one of the parties that executed the foregoing instrument;
and that she signed her name thereto by order of the Board of Directors of said
association.

-------------------------
Notary Public

[NOTARIAL SEAL]


<PAGE>

STATE OF ILLINOIS             )
                              ss.:

COUNTY OF COOK                )

            On this 30th day of March, 2006, before me, a notary public in and
for the State of Illinois, personally appeared Melissa A. Rosal, known to me
who, being by me duly sworn, did depose and say that she resides in Chicago,
Illinois; that she is a Vice President of U.S. Bank National Association, a
national banking association, one of the parties that executed the foregoing
instrument; and that she signed her name thereto by order of the Board of
Directors of said association.

-------------------------
Notary Public

[NOTARIAL SEAL]


<PAGE>

                                   SCHEDULE I

                    Wells Fargo Asset Securities Corporation,
                Mortgage Pass-Through Certificates, Series 2006-4
                 Applicable Unscheduled Principal Receipt Period

                                 Full Unscheduled         Partial Unscheduled
Servicer                        Principal Receipts        Principal Receipts
------------------------------  ------------------        ------------------
Wells Fargo Bank                     Mid-Month                 Mid-Month




<PAGE>

                                   SCHEDULE II

                          Schedule for TAC Certificates

            The following table sets forth for each Distribution Date the
targeted Principal Balances for the TAC Certificates expressed as a percentage
of the initial Principal Balance of the TAC Certificates.

                           Targeted Principal Balances
                   as Percentages of Initial Principal Balance
                                TAC Certificates
<TABLE>
<CAPTION>
                            Percentage of                             Percentage of                              Percentage of
                               Initial                                   Initial                                    Initial
                              Principal                                 Principal                                  Principal
  Distribution Date            Balance        Distribution Date          Balance        Distribution Date           Balance
--------------------        -------------    -------------------      -------------    -------------------       -------------
<S>                          <C>             <C>                       <C>             <C>                        <C>
April 2006                   99.93982078%    January 2010              83.08525076%    October 2013               73.62391054%
May 2006                      99.87957053    February 2010              82.58578232    November 2013               73.55565553
June 2006                     99.81924896    March 2010                 82.09530049    December 2013               73.48729082
July 2006                     99.75885568    April 2010                 81.61375046    January 2014                73.41881588
August 2006                   99.69839038    May 2010                   81.14107781    February 2014               73.35023018
September 2006                99.63785269    June 2010                  80.67722838    March 2014                  73.28153319
October 2006                  99.57724228    July 2010                  80.22214835    April 2014                  73.21272438
November 2006                 99.51655879    August 2010                79.77578419    May 2014                    73.14380322
December 2006                 99.45580190    September 2010             79.33808272    June 2014                   73.07476916
January 2007                  99.39497122    October 2010               78.90899106    July 2014                   73.00562166
February 2007                 99.33406640    November 2010              78.48845659    August 2014                 72.93636019
March 2007                    99.27308710    December 2010              78.07642706    September 2014              72.86698418
April 2007                    99.21203297    January 2011               77.67285050    October 2014                72.79749310
May 2007                      99.15090365    February 2011              77.27767525    November 2014               72.72788640
June 2007                     99.06026644    March 2011                 76.89084993    December 2014               72.65816351
July 2007                     98.92090222    April 2011                 76.68198659    January 2015                72.58832388
August 2007                   98.73336057    May 2011                   76.48120006    February 2015               72.51836697
September 2007                98.49821934    June 2011                  76.28844049    March 2015                  72.44829218
October 2007                  98.21608421    July 2011                  76.10365834    April 2015                  72.37809899
November 2007                 97.88758815    August 2011                75.92680438    May 2015                    72.30778678
December 2007                 97.51339099    September 2011             75.75782968    June 2015                   72.23735503
January 2008                  97.09417881    October 2011               75.59668556    July 2015                   72.16680313
February 2008                 96.63066347    November 2011              75.44332365    August 2015                 72.09613054
March 2008                    96.12358194    December 2011              75.29769585    September 2015              71.80641593
April 2008                    95.57369576    January 2012               75.15975438    October 2015                71.15132231
May 2008                      94.98179035    February 2012              75.02945171    November 2015               70.49964474
June 2008                     94.34867438    March 2012                 74.90674057    December 2015               69.85136006
July 2008                     93.67517907    April 2012                 74.83432579    January 2016                69.20644529
August 2008                   93.00583560    May 2012                   74.76795837    February 2016               68.56261165
September 2008                92.34489416    June 2012                  74.70149028    March 2016                  67.90705541
October 2008                  91.69392144    July 2012                  74.63492106    April 2016                  67.25491641
November 2008                 91.05285688    August 2012                74.56825021    May 2016                    66.60617144
December 2008                 90.42164037    September 2012             74.50147724    June 2016                   65.96079744
January 2009                  89.80021204    October 2012               74.43460168    July 2016                   65.31877144
February 2009                 89.18851246    November 2012              74.36762301    August 2016                 64.68007062
March 2009                    88.58648249    December 2012              74.30054076    September 2016              64.04467225
April 2009                    87.99406337    January 2013               74.23335443    October 2016                63.41255374
May 2009                      87.41119668    February 2013              74.16606351    November 2016               62.78369263
June 2009                     86.83782431    March 2013                 74.09866751    December 2016               62.15806657
July 2009                     86.27388854    April 2013                 74.03116591    January 2017                61.53565332
August 2009                   85.71933194    May 2013                   73.96355824    February 2017               60.91643078
September 2009                85.17409746    June 2013                  73.89584396    March 2017                  60.30037694
October 2009                  84.63812834    July 2013                  73.82802256    April 2017                  59.68746991
November 2009                 84.11136819    August 2013                73.76009353    May 2017                    59.07768796
December 2009                 83.59376091    September 2013             73.69205637    June 2017                   58.47100941
</TABLE>


<PAGE>

<TABLE>
<S>                          <C>             <C>                       <C>             <C>                        <C>
July 2017                    57.86741275%    September 2021            31.13430719%    November 2025              9.51487569%
August 2017                   57.26687653    October 2021               30.65560538    December 2025               9.12433782
September 2017                56.66937946    November 2021              30.17904691    January 2026                8.73519656
October 2017                  56.07490035    December 2021              29.70461507    February 2026               8.34743857
November 2017                 55.48341809    January 2022               29.23229322    March 2026                  7.96105063
December 2017                 54.89491174    February 2022              28.76206485    April 2026                  7.57601950
January 2018                   54.30936041   March 2022                 28.29391349    May 2026                    7.19233207
February 2018                 53.72674334    April 2022                 27.82782275    June 2026                   6.80997522
March 2018                    53.14703991    May 2022                   27.36377632    July 2026                   6.42893593
April 2018                    52.57022956    June 2022                  26.90175800    August 2026                 6.04920121
May 2018                      51.99629187    July 2022                  26.44175163    September 2026              5.67075813
June 2018                     51.42520650    August 2022                25.98374113    October 2026                5.29359381
July 2018                     50.85695324    September 2022             25.52771051    November 2026               4.91769543
August 2018                   50.29151196    October 2022               25.07364387    December 2026               4.54305019
September 2018                49.72886266    November 2022              24.62152534    January 2027                4.16964540
October 2018                  49.16898544    December 2022              24.17133916    February 2027               3.79746835
November 2018                 48.61186050    January 2023               23.72306963    March 2027                  3.42650646
December 2018                 48.05746810    February 2023              23.27670113    April 2027                  3.05674712
January 2019                  47.50578868    March 2023                 22.83221812    May 2027                    2.68817782
February 2019                 46.95680271    April 2023                 22.38960512    June 2027                   2.32078609
March 2019                    46.41049081    May 2023                   21.94884671    July 2027                   1.95455949
April 2019                    45.86683366    June 2023                  21.50992756    August 2027                 1.58948566
May 2019                      45.32581207    July 2023                  21.07283243    September 2027              1.22555225
June 2019                     44.78740694    August 2023                20.63754610    October 2027                0.86274699
July 2019                     44.25159925    September 2023             20.20405347    November 2027               0.50105765
August 2019                   43.71837009    October 2023               19.77233947    December 2027               0.14047202
September 2019                43.18770066    November 2023              19.34238913    January 2028 and            0.00000000
                                                                                       --------------------
                                                                                       thereafter
October 2019                  42.65957224    December 2023              18.91418751
November 2019                 42.13396618    January 2024               18.48771979
December 2019                 41.61086397    February 2024              18.06297118
January 2020                  41.09024718    March 2024                 17.63992696
February 2020                 40.57209746    April 2024                 17.21857249
March 2020                    40.05639656    May 2024                   16.79889316
April 2020                    39.54312631    June 2024                  16.38087450
May 2020                      39.03226866    July 2024                  15.96450203
June 2020                     38.52380562    August 2024                15.54976135
July 2020                     38.01771929    September 2024             15.13663816
August 2020                   37.51399191    October 2024               14.72511821
September 2020                37.01260574    November 2024              14.31518726
October 2020                  36.51354315    December 2024              13.90683121
November 2020                 36.01678663    January 2025               13.50003597
December 2020                 35.52231871    February 2025              13.09478754
January 2021                  35.03012204    March 2025                 12.69107197
February 2021                 34.54017934    April 2025                 12.28887535
March 2021                    34.05247343    May 2025                   11.88818387
April 2021                    33.56055635    June 2025                  11.48898375
May 2021                      33.07088454    July 2025                  11.09126126
June 2021                     32.58344078    August 2025                10.69500279
July 2021                     32.09820799    September 2025             10.30019472
August 2021                   31.61516910    October 2025                9.90682352
</TABLE>

<PAGE>

                                 EXHIBIT A-I-A-1
                    [FORM OF FACE OF CLASS I-A-1 CERTIFICATE]

  [UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE
   DEPOSITORY TRUST COMPANY TO THE DEPOSITOR OR ITS AGENT FOR REGISTRATION OF
 TRANSFER, EXCHANGE OR PAYMENT, AND ANY CERTIFICATE ISSUED IS REGISTERED IN THE
       NAME OF CEDE & CO. OR SUCH OTHER NAME AS REQUESTED BY AN AUTHORIZED
REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY AND ANY PAYMENT IS MADE TO CEDE &
  CO., ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO
  ANY PERSON IS WRONGFUL SINCE THE REGISTERED OWNER HEREOF, CEDE & CO., HAS AN
                                INTEREST HEREIN.]

                        MORTGAGE PASS-THROUGH CERTIFICATE
                           SERIES 2006-4, CLASS I-A-1

                    evidencing an interest in a pool of fixed
                           interest rate, monthly pay,
                      fully amortizing, first lien, one- to
                 four-family residential mortgage loans sold by

                    WELLS FARGO ASSET SECURITIES CORPORATION
               (Not an interest in or obligation of the Depositor)

            THIS CERTIFICATE DOES NOT EVIDENCE AN OBLIGATION OF, OR AN INTEREST
IN, THE DEPOSITOR, THE MASTER SERVICER, THE TRUSTEE OR ANY OF THEIR AFFILIATES,
AND IS NOT INSURED OR GUARANTEED BY THE DEPOSITOR, THE MASTER SERVICER, THE
TRUSTEE OR ANY OF THEIR AFFILIATES, OR BY ANY GOVERNMENT AGENCY OR PRIVATE
INSURER.

            DISTRIBUTIONS IN REDUCTION OF THE PRINCIPAL BALANCE OF THIS
CERTIFICATE WILL BE MADE IN THE MANNER DESCRIBED IN THE AGREEMENT. ACCORDINGLY,
THE OUTSTANDING PRINCIPAL BALANCE OF THIS CERTIFICATE AT ANY TIME MAY BE LESS
THAN THE INITIAL PRINCIPAL BALANCE REPRESENTED HEREBY.

Certificate No.                        Cut-Off Date:  March 1, 2006

CUSIP No.: 94983B AA 7                 First Distribution Date: April 25, 2006

ISIN No.: US94983BAA70                 Denomination:  $

Percentage Interest evidenced          Final Scheduled Maturity Date:  April 25,
by this Certificate: %                 2036


      THIS CERTIFIES THAT ___________________________ is the registered owner of
the Percentage Interest evidenced by this Certificate in monthly distributions
to the Holders of the Class I-A-1 Certificates with respect to a Trust Estate
consisting of a pool of fixed interest rate, monthly pay, fully amortizing,
first lien, one- to four-family residential mortgage loans, other than the Fixed
Retained Yield, if any, with respect thereto, consisting of two loan groups (the
"Group I Mortgage Loans" and "Group II Mortgage Loans," respectively), formed by
Wells Fargo Asset Securities Corporation (hereinafter called the "Depositor,"
which term includes any successor entity under the Agreement referred to below).
The Trust Estate was created pursuant to a Pooling and Servicing Agreement dated
as of March 30, 2006 (the "Agreement") among the Depositor, Wells Fargo Bank,
N.A., as master servicer (the "Master Servicer") and U.S. Bank National
Association, as trustee (the "Trustee"), a summary of certain of the pertinent
provisions of which is set forth hereinafter. To the extent not defined herein,
the capitalized terms used herein have the meanings ascribed to such terms in
the Agreement. This Certificate is issued under and is subject to the terms,
provisions and conditions of the Agreement, to which Agreement the Holder of
this Certificate by virtue of the acceptance hereof assents and by which such
Holder is bound.

      Pursuant to the terms of the Agreement, a distribution will be made on the
25th day of each month or, if such 25th day is not a Business Day, the Business
Day immediately following (the "Distribution Date"), commencing on the first
Distribution Date specified above, to the Person in whose name this Certificate
is registered at the close of business on the Record Date, in an amount equal to
the product of the Percentage Interest evidenced by this Certificate and the
Group I-A Distribution Amount for the Class I-A-1 Certificates required to be
distributed to Holders of the Class I-A-1 Certificates on such Distribution
Date, subject to adjustment in certain events as specified in the Agreement.
Distributions in reduction of the Principal Balance of certain Classes of Class
A Certificates may not commence on the first Distribution Date specified above.
Distributions of principal will be allocated among the Classes of Group I-A
Certificates in accordance with the provisions of the Agreement. The
pass-through rate on the Class I-A-1 Certificates applicable to each
Distribution Date will be 5.750% per annum. The amount of interest which accrues
on this Certificate in any month will be subject to reduction with respect to
any Non-Supported Interest Shortfall, any Relief Act Shortfall and the interest
portion of certain Realized Losses allocated to the Class I-A-1 Certificates, as
described in the Agreement.

      Distributions on this Certificate will be made by the Paying Agent by
check mailed to the address of the Person entitled thereto, as such name and
address shall appear on the Certificate Register, unless such Person is entitled
to receive payments by wire transfer in immediately available funds in
accordance with the Agreement and such Person has notified the Paying Agent
pursuant to the Agreement that such payments are to be made by wire transfer of
immediately available funds. Notwithstanding the above, the final distribution
in reduction of the Principal Balance of this Certificate will be made after due
notice of the pendency of such distribution and only upon presentation and
surrender of this Certificate at the office or agency of the Paying Agent
specified for that purpose in the notice of final distribution.

      Reference is hereby made to the further provisions of this Certificate set
forth on the reverse hereof, which further provisions shall for all purposes
have the same effect as if set forth at this place.

      This Certificate constitutes a "regular interest" in a "real estate
mortgage investment conduit" as those terms are defined in Section 860G(a)(1)
and Section 860D, respectively, of the Internal Revenue Code of 1986, as
amended.

      Unless this Certificate has been countersigned by an authorized officer of
the Authenticating Agent, by manual signature, this Certificate shall not be
entitled to any benefit under the Agreement or be valid for any purpose.


<PAGE>

      IN WITNESS WHEREOF, the Paying Agent has caused this Certificate to be
duly executed as of the date set forth below.

Dated:

                                       Wells Fargo Bank, N.A.,
                                            Paying Agent

                                       By____________________________
                                            Authorized Officer

Countersigned:

Wells Fargo Bank, N.A.,
  Authenticating Agent

By ________________________
   Authorized Officer


<PAGE>


                                 EXHIBIT A-I-A-2
                    [FORM OF FACE OF CLASS I-A-2 CERTIFICATE]

  [UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE
   DEPOSITORY TRUST COMPANY TO THE DEPOSITOR OR ITS AGENT FOR REGISTRATION OF
 TRANSFER, EXCHANGE OR PAYMENT, AND ANY CERTIFICATE ISSUED IS REGISTERED IN THE
       NAME OF CEDE & CO. OR SUCH OTHER NAME AS REQUESTED BY AN AUTHORIZED
REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY AND ANY PAYMENT IS MADE TO CEDE &
  CO., ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO
  ANY PERSON IS WRONGFUL SINCE THE REGISTERED OWNER HEREOF, CEDE & CO., HAS AN
                                INTEREST HEREIN.]

                        MORTGAGE PASS-THROUGH CERTIFICATE
                           SERIES 2006-4, CLASS I-A-2

                    evidencing an interest in a pool of fixed
                           interest rate, monthly pay,
                      fully amortizing, first lien, one- to
                 four-family residential mortgage loans sold by

                    WELLS FARGO ASSET SECURITIES CORPORATION
               (Not an interest in or obligation of the Depositor)

            THIS CERTIFICATE DOES NOT EVIDENCE AN OBLIGATION OF, OR AN INTEREST
IN, THE DEPOSITOR, THE MASTER SERVICER, THE TRUSTEE OR ANY OF THEIR AFFILIATES,
AND IS NOT INSURED OR GUARANTEED BY THE DEPOSITOR, THE MASTER SERVICER, THE
TRUSTEE OR ANY OF THEIR AFFILIATES, OR BY ANY GOVERNMENT AGENCY OR PRIVATE
INSURER.

            DISTRIBUTIONS IN REDUCTION OF THE PRINCIPAL BALANCE OF THIS
CERTIFICATE WILL BE MADE IN THE MANNER DESCRIBED IN THE AGREEMENT. ACCORDINGLY,
THE OUTSTANDING PRINCIPAL BALANCE OF THIS CERTIFICATE AT ANY TIME MAY BE LESS
THAN THE INITIAL PRINCIPAL BALANCE REPRESENTED HEREBY.

Certificate No.                        Cut-Off Date:  March 1, 2006

CUSIP No.: 94983B AB 5                 First Distribution Date: April 25, 2006

ISIN No.: US94983BAB53                 Denomination:  $

Percentage Interest evidenced          Final Scheduled Maturity Date:  April 25,
by this Certificate: %                 2036


      THIS CERTIFIES THAT ___________________________ is the registered owner of
the Percentage Interest evidenced by this Certificate in monthly distributions
to the Holders of the Class I-A-2 Certificates with respect to a Trust Estate
consisting of a pool of fixed interest rate, monthly pay, fully amortizing,
first lien, one- to four-family residential mortgage loans, other than the Fixed
Retained Yield, if any, with respect thereto, consisting of two loan groups (the
"Group I Mortgage Loans" and "Group II Mortgage Loans," respectively), formed by
Wells Fargo Asset Securities Corporation (hereinafter called the "Depositor,"
which term includes any successor entity under the Agreement referred to below).
The Trust Estate was created pursuant to a Pooling and Servicing Agreement dated
as of March 30, 2006 (the "Agreement") among the Depositor, Wells Fargo Bank,
N.A., as master servicer (the "Master Servicer") and U.S. Bank National
Association, as trustee (the "Trustee"), a summary of certain of the pertinent
provisions of which is set forth hereinafter. To the extent not defined herein,
the capitalized terms used herein have the meanings ascribed to such terms in
the Agreement. This Certificate is issued under and is subject to the terms,
provisions and conditions of the Agreement, to which Agreement the Holder of
this Certificate by virtue of the acceptance hereof assents and by which such
Holder is bound.

      Pursuant to the terms of the Agreement, a distribution will be made on the
25th day of each month or, if such 25th day is not a Business Day, the Business
Day immediately following (the "Distribution Date"), commencing on the first
Distribution Date specified above, to the Person in whose name this Certificate
is registered at the close of business on the Record Date, in an amount equal to
the product of the Percentage Interest evidenced by this Certificate and the
Group I-A Distribution Amount for the Class I-A-2 Certificates required to be
distributed to Holders of the Class I-A-2 Certificates on such Distribution
Date, subject to adjustment in certain events as specified in the Agreement.
Distributions in reduction of the Principal Balance of certain Classes of Class
A Certificates may not commence on the first Distribution Date specified above.
Distributions of principal will be allocated among the Classes of Group I-A
Certificates in accordance with the provisions of the Agreement. The
pass-through rate on the Class I-A-2 Certificates applicable to each
Distribution Date will be 5.750% per annum. The amount of interest which accrues
on this Certificate in any month will be subject to reduction with respect to
any Non-Supported Interest Shortfall, any Relief Act Shortfall and the interest
portion of certain Realized Losses allocated to the Class I-A-2 Certificates, as
described in the Agreement.

      Distributions on this Certificate will be made by the Paying Agent by
check mailed to the address of the Person entitled thereto, as such name and
address shall appear on the Certificate Register, unless such Person is entitled
to receive payments by wire transfer in immediately available funds in
accordance with the Agreement and such Person has notified the Paying Agent
pursuant to the Agreement that such payments are to be made by wire transfer of
immediately available funds. Notwithstanding the above, the final distribution
in reduction of the Principal Balance of this Certificate will be made after due
notice of the pendency of such distribution and only upon presentation and
surrender of this Certificate at the office or agency of the Paying Agent
specified for that purpose in the notice of final distribution.

      Reference is hereby made to the further provisions of this Certificate set
forth on the reverse hereof, which further provisions shall for all purposes
have the same effect as if set forth at this place.

      This Certificate constitutes a "regular interest" in a "real estate
mortgage investment conduit" as those terms are defined in Section 860G(a)(1)
and Section 860D, respectively, of the Internal Revenue Code of 1986, as
amended.

      Unless this Certificate has been countersigned by an authorized officer of
the Authenticating Agent, by manual signature, this Certificate shall not be
entitled to any benefit under the Agreement or be valid for any purpose.


<PAGE>

            IN WITNESS WHEREOF, the Paying Agent has caused this Certificate to
be duly executed as of the date set forth below.

Dated:

                                       Wells Fargo Bank, N.A.,
                                            Paying Agent

                                       By____________________________
                                            Authorized Officer

Countersigned:

Wells Fargo Bank, N.A.,
  Authenticating Agent

By ________________________
   Authorized Officer


<PAGE>

                                 EXHIBIT A-I-A-3
                    [FORM OF FACE OF CLASS I-A-3 CERTIFICATE]

  [UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE
   DEPOSITORY TRUST COMPANY TO THE DEPOSITOR OR ITS AGENT FOR REGISTRATION OF
 TRANSFER, EXCHANGE OR PAYMENT, AND ANY CERTIFICATE ISSUED IS REGISTERED IN THE
       NAME OF CEDE & CO. OR SUCH OTHER NAME AS REQUESTED BY AN AUTHORIZED
REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY AND ANY PAYMENT IS MADE TO CEDE &
  CO., ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO
  ANY PERSON IS WRONGFUL SINCE THE REGISTERED OWNER HEREOF, CEDE & CO., HAS AN
                                INTEREST HEREIN.]

                        MORTGAGE PASS-THROUGH CERTIFICATE
                           SERIES 2006-4, CLASS I-A-3

                    evidencing an interest in a pool of fixed
                           interest rate, monthly pay,
                      fully amortizing, first lien, one- to
                 four-family residential mortgage loans sold by

                    WELLS FARGO ASSET SECURITIES CORPORATION
               (Not an interest in or obligation of the Depositor)

            THIS CERTIFICATE DOES NOT EVIDENCE AN OBLIGATION OF, OR AN INTEREST
IN, THE DEPOSITOR, THE MASTER SERVICER, THE TRUSTEE OR ANY OF THEIR AFFILIATES,
AND IS NOT INSURED OR GUARANTEED BY THE DEPOSITOR, THE MASTER SERVICER, THE
TRUSTEE OR ANY OF THEIR AFFILIATES, OR BY ANY GOVERNMENT AGENCY OR PRIVATE
INSURER.

            UNTIL THE APPLICABLE ACCRETION TERMINATION DATE, THE INTEREST THAT
ACCRUES ON THE PRINCIPAL BALANCE OF THIS CERTIFICATE WILL NOT BE PAYABLE BECAUSE
SUCH UNPAID INTEREST IS ADDED TO THE PRINCIPAL BALANCE OF THIS CERTIFICATE AND
BECAUSE DISTRIBUTIONS IN REDUCTION OF THE PRINCIPAL BALANCE WILL BE MADE IN THE
MANNER DESCRIBED IN THE AGREEMENT, THE OUTSTANDING PRINCIPAL BALANCE OF THIS
CERTIFICATE AT ANY TIME MAY BE MORE OR LESS THAN THE INITIAL PRINCIPAL BALANCE
REPRESENTED HEREBY.

Certificate No.                        Cut-Off Date:  March 1, 2006

CUSIP No.: 94983B AC 3                 First Distribution Date: April 25, 2006

ISIN No.: US94983BAC37                 Denomination:  $

Percentage Interest evidenced          Final Scheduled Maturity Date:  April 25,
by this Certificate: %                 2036


      THIS CERTIFIES THAT ___________________________ is the registered owner of
the Percentage Interest evidenced by this Certificate in monthly distributions
to the Holders of the Class I-A-3 Certificates with respect to a Trust Estate
consisting of a pool of fixed interest rate, monthly pay, fully amortizing,
first lien, one- to four-family residential mortgage loans, other than the Fixed
Retained Yield, if any, with respect thereto, consisting of two loan groups (the
"Group I Mortgage Loans" and "Group II Mortgage Loans," respectively), formed by
Wells Fargo Asset Securities Corporation (hereinafter called the "Depositor,"
which term includes any successor entity under the Agreement referred to below).
The Trust Estate was created pursuant to a Pooling and Servicing Agreement dated
as of March 30, 2006 (the "Agreement") among the Depositor, Wells Fargo Bank,
N.A., as master servicer (the "Master Servicer") and U.S. Bank National
Association, as trustee (the "Trustee"), a summary of certain of the pertinent
provisions of which is set forth hereinafter. To the extent not defined herein,
the capitalized terms used herein have the meanings ascribed to such terms in
the Agreement. This Certificate is issued under and is subject to the terms,
provisions and conditions of the Agreement, to which Agreement the Holder of
this Certificate by virtue of the acceptance hereof assents and by which such
Holder is bound.

      Pursuant to the terms of the Agreement, a distribution will be made on the
25th day of each month or, if such 25th day is not a Business Day, the Business
Day immediately following (the "Distribution Date"), commencing on the first
Distribution Date specified above, to the Person in whose name this Certificate
is registered at the close of business on the Record Date, in an amount equal to
the product of the Percentage Interest evidenced by this Certificate and the
Group I-A Distribution Amount for the Class I-A-3 Certificates required to be
distributed to Holders of the Class I-A-3 Certificates on such Distribution
Date, subject to adjustment in certain events as specified in the Agreement.
Distributions in reduction of the Principal Balance of certain Classes of Class
A Certificates may not commence on the first Distribution Date specified above.
Distributions of principal will be allocated among the Classes of Group I-A
Certificates in accordance with the provisions of the Agreement. Prior to the
applicable Accretion Termination Date, no distribution of interest on this
Certificate will be made. Prior to the applicable Accretion Termination Date,
interest otherwise available for distribution on this Certificate will be added
to the Principal Balance of the Class I-A-3 Certificates on each Distribution
Date. The pass-through rate on the Class I-A-3 Certificates applicable to each
Distribution Date will be 5.750% per annum. The amount of interest which accrues
on this Certificate in any month will be subject to reduction with respect to
any Non-Supported Interest Shortfall, any Relief Act Shortfall and the interest
portion of certain Realized Losses allocated to the Class I-A-3 Certificates, as
described in the Agreement.

      Distributions on this Certificate will be made by the Paying Agent by
check mailed to the address of the Person entitled thereto, as such name and
address shall appear on the Certificate Register, unless such Person is entitled
to receive payments by wire transfer in immediately available funds in
accordance with the Agreement and such Person has notified the Paying Agent
pursuant to the Agreement that such payments are to be made by wire transfer of
immediately available funds. Notwithstanding the above, the final distribution
in reduction of the Principal Balance of this Certificate will be made after due
notice of the pendency of such distribution and only upon presentation and
surrender of this Certificate at the office or agency of the Paying Agent
specified for that purpose in the notice of final distribution.

      Reference is hereby made to the further provisions of this Certificate set
forth on the reverse hereof, which further provisions shall for all purposes
have the same effect as if set forth at this place.

      This Certificate constitutes a "regular interest" in a "real estate
mortgage investment conduit" as those terms are defined in Section 860G(a)(1)
and Section 860D, respectively, of the Internal Revenue Code of 1986, as
amended.

      Unless this Certificate has been countersigned by an authorized officer of
the Authenticating Agent, by manual signature, this Certificate shall not be
entitled to any benefit under the Agreement or be valid for any purpose.


<PAGE>

      IN WITNESS WHEREOF, the Paying Agent has caused this Certificate to be
duly executed as of the date set forth below.

Dated:

                                       Wells Fargo Bank, N.A.,
                                            Paying Agent

                                       By____________________________
                                            Authorized Officer

Countersigned:

Wells Fargo Bank, N.A.,
  Authenticating Agent

By ________________________
   Authorized Officer


<PAGE>

                                 EXHIBIT A-I-A-4
                    [FORM OF FACE OF CLASS I-A-4 CERTIFICATE]

  [UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE
   DEPOSITORY TRUST COMPANY TO THE DEPOSITOR OR ITS AGENT FOR REGISTRATION OF
 TRANSFER, EXCHANGE OR PAYMENT, AND ANY CERTIFICATE ISSUED IS REGISTERED IN THE
       NAME OF CEDE & CO. OR SUCH OTHER NAME AS REQUESTED BY AN AUTHORIZED
REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY AND ANY PAYMENT IS MADE TO CEDE &
  CO., ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO
  ANY PERSON IS WRONGFUL SINCE THE REGISTERED OWNER HEREOF, CEDE & CO., HAS AN
                                INTEREST HEREIN.]

                        MORTGAGE PASS-THROUGH CERTIFICATE
                           SERIES 2006-4, CLASS I-A-4

                    evidencing an interest in a pool of fixed
                           interest rate, monthly pay,
                      fully amortizing, first lien, one- to
                 four-family residential mortgage loans sold by

                    WELLS FARGO ASSET SECURITIES CORPORATION
               (Not an interest in or obligation of the Depositor)

            AFTER THE APPLICABLE SUBORDINATION DEPLETION DATE, THE PRINCIPAL
PORTION OF REALIZED LOSSES ALLOCATED TO THE CLASS I-A-3 CERTIFICATES WILL BE
BORNE BY THE CLASS I-A-4 CERTIFICATES AS DESCRIBED IN THE AGREEMENT.

            THIS CERTIFICATE DOES NOT EVIDENCE AN OBLIGATION OF, OR AN INTEREST
IN, THE DEPOSITOR, THE MASTER SERVICER, THE TRUSTEE OR ANY OF THEIR AFFILIATES,
AND IS NOT INSURED OR GUARANTEED BY THE DEPOSITOR, THE MASTER SERVICER, THE
TRUSTEE OR ANY OF THEIR AFFILIATES, OR BY ANY GOVERNMENT AGENCY OR PRIVATE
INSURER.

            UNTIL THE APPLICABLE ACCRETION TERMINATION DATE, THE INTEREST THAT
ACCRUES ON THE PRINCIPAL BALANCE OF THIS CERTIFICATE WILL NOT BE PAYABLE BECAUSE
SUCH UNPAID INTEREST IS ADDED TO THE PRINCIPAL BALANCE OF THIS CERTIFICATE AND
BECAUSE DISTRIBUTIONS IN REDUCTION OF THE PRINCIPAL BALANCE WILL BE MADE IN THE
MANNER DESCRIBED IN THE AGREEMENT, THE OUTSTANDING PRINCIPAL BALANCE OF THIS
CERTIFICATE AT ANY TIME MAY BE MORE OR LESS THAN THE INITIAL PRINCIPAL BALANCE
REPRESENTED HEREBY.

Certificate No.                        Cut-Off Date:  March 1, 2006

CUSIP No.: 94983B AD 1                 First Distribution Date: April 25, 2006

ISIN No.: US94983BAD10                 Denomination:  $

Percentage Interest evidenced          Final Scheduled Maturity Date:  April 25,
by this Certificate: %                 2036


      THIS CERTIFIES THAT ___________________________ is the registered owner of
the Percentage Interest evidenced by this Certificate in monthly distributions
to the Holders of the Class I-A-4 Certificates with respect to a Trust Estate
consisting of a pool of fixed interest rate, monthly pay, fully amortizing,
first lien, one- to four-family residential mortgage loans, other than the Fixed
Retained Yield, if any, with respect thereto, consisting of two loan groups (the
"Group I Mortgage Loans" and "Group II Mortgage Loans," respectively), formed by
Wells Fargo Asset Securities Corporation (hereinafter called the "Depositor,"
which term includes any successor entity under the Agreement referred to below).
The Trust Estate was created pursuant to a Pooling and Servicing Agreement dated
as of March 30, 2006 (the "Agreement") among the Depositor, Wells Fargo Bank,
N.A., as master servicer (the "Master Servicer") and U.S. Bank National
Association, as trustee (the "Trustee"), a summary of certain of the pertinent
provisions of which is set forth hereinafter. To the extent not defined herein,
the capitalized terms used herein have the meanings ascribed to such terms in
the Agreement. This Certificate is issued under and is subject to the terms,
provisions and conditions of the Agreement, to which Agreement the Holder of
this Certificate by virtue of the acceptance hereof assents and by which such
Holder is bound.

      Pursuant to the terms of the Agreement, a distribution will be made on the
25th day of each month or, if such 25th day is not a Business Day, the Business
Day immediately following (the "Distribution Date"), commencing on the first
Distribution Date specified above, to the Person in whose name this Certificate
is registered at the close of business on the Record Date, in an amount equal to
the product of the Percentage Interest evidenced by this Certificate and the
Group I-A Distribution Amount for the Class I-A-4 Certificates required to be
distributed to Holders of the Class I-A-4 Certificates on such Distribution
Date, subject to adjustment in certain events as specified in the Agreement.
Distributions in reduction of the Principal Balance of certain Classes of Class
A Certificates may not commence on the first Distribution Date specified above.
Distributions of principal will be allocated among the Classes of Group I-A
Certificates in accordance with the provisions of the Agreement. Prior to the
applicable Accretion Termination Date, no distribution of interest on this
Certificate will be made. Prior to the applicable Accretion Termination Date,
interest otherwise available for distribution on this Certificate will be added
to the Principal Balance of the Class I-A-4 Certificates on each Distribution
Date. The pass-through rate on the Class I-A-4 Certificates applicable to each
Distribution Date will be 5.750% per annum. The amount of interest which accrues
on this Certificate in any month will be subject to reduction with respect to
any Non-Supported Interest Shortfall, any Relief Act Shortfall and the interest
portion of certain Realized Losses allocated to the Class I-A-4 Certificates, as
described in the Agreement.

      Distributions on this Certificate will be made by the Paying Agent by
check mailed to the address of the Person entitled thereto, as such name and
address shall appear on the Certificate Register, unless such Person is entitled
to receive payments by wire transfer in immediately available funds in
accordance with the Agreement and such Person has notified the Paying Agent
pursuant to the Agreement that such payments are to be made by wire transfer of
immediately available funds. Notwithstanding the above, the final distribution
in reduction of the Principal Balance of this Certificate will be made after due
notice of the pendency of such distribution and only upon presentation and
surrender of this Certificate at the office or agency of the Paying Agent
specified for that purpose in the notice of final distribution.

      Reference is hereby made to the further provisions of this Certificate set
forth on the reverse hereof, which further provisions shall for all purposes
have the same effect as if set forth at this place.

      This Certificate constitutes a "regular interest" in a "real estate
mortgage investment conduit" as those terms are defined in Section 860G(a)(1)
and Section 860D, respectively, of the Internal Revenue Code of 1986, as
amended.

      Unless this Certificate has been countersigned by an authorized officer of
the Authenticating Agent, by manual signature, this Certificate shall not be
entitled to any benefit under the Agreement or be valid for any purpose.


<PAGE>

      IN WITNESS WHEREOF, the Paying Agent has caused this Certificate to be
duly executed as of the date set forth below.

Dated:

                                       Wells Fargo Bank, N.A.,
                                            Paying Agent

                                       By____________________________
                                            Authorized Officer

Countersigned:

Wells Fargo Bank, N.A.,
  Authenticating Agent

By ________________________
   Authorized Officer


<PAGE>

                                 EXHIBIT A-I-A-5
                    [FORM OF FACE OF CLASS I-A-5 CERTIFICATE]

  [UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE
   DEPOSITORY TRUST COMPANY TO THE DEPOSITOR OR ITS AGENT FOR REGISTRATION OF
 TRANSFER, EXCHANGE OR PAYMENT, AND ANY CERTIFICATE ISSUED IS REGISTERED IN THE
       NAME OF CEDE & CO. OR SUCH OTHER NAME AS REQUESTED BY AN AUTHORIZED
REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY AND ANY PAYMENT IS MADE TO CEDE &
  CO., ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO
  ANY PERSON IS WRONGFUL SINCE THE REGISTERED OWNER HEREOF, CEDE & CO., HAS AN
                                INTEREST HEREIN.]

                        MORTGAGE PASS-THROUGH CERTIFICATE
                           SERIES 2006-4, CLASS I-A-5

                    evidencing an interest in a pool of fixed
                           interest rate, monthly pay,
                      fully amortizing, first lien, one- to
                 four-family residential mortgage loans sold by

                    WELLS FARGO ASSET SECURITIES CORPORATION
               (Not an interest in or obligation of the Depositor)

            THIS CERTIFICATE DOES NOT EVIDENCE AN OBLIGATION OF, OR AN INTEREST
IN, THE DEPOSITOR, THE MASTER SERVICER, THE TRUSTEE OR ANY OF THEIR AFFILIATES,
AND IS NOT INSURED OR GUARANTEED BY THE DEPOSITOR, THE MASTER SERVICER, THE
TRUSTEE OR ANY OF THEIR AFFILIATES, OR BY ANY GOVERNMENT AGENCY OR PRIVATE
INSURER.

            DISTRIBUTIONS IN REDUCTION OF THE PRINCIPAL BALANCE OF THIS
CERTIFICATE WILL BE MADE IN THE MANNER DESCRIBED IN THE AGREEMENT. ACCORDINGLY,
THE OUTSTANDING PRINCIPAL BALANCE OF THIS CERTIFICATE AT ANY TIME MAY BE LESS
THAN THE INITIAL PRINCIPAL BALANCE REPRESENTED HEREBY.

Certificate No.                        Cut-Off Date:  March 1, 2006

CUSIP No.:  94983B AE 9                First Distribution Date: April 25, 2006

ISIN No.: US94983BAE92                 Denomination:  $

Percentage Interest evidenced          Final Scheduled Maturity Date:  April 25,
by this Certificate: %                 2036


      THIS CERTIFIES THAT ___________________________ is the registered owner of
the Percentage Interest evidenced by this Certificate in monthly distributions
to the Holders of the Class I-A-5 Certificates with respect to a Trust Estate
consisting of a pool of fixed interest rate, monthly pay, fully amortizing,
first lien, one- to four-family residential mortgage loans, other than the Fixed
Retained Yield, if any, with respect thereto, consisting of two loan groups (the
"Group I Mortgage Loans" and "Group II Mortgage Loans," respectively), formed by
Wells Fargo Asset Securities Corporation (hereinafter called the "Depositor,"
which term includes any successor entity under the Agreement referred to below).
The Trust Estate was created pursuant to a Pooling and Servicing Agreement dated
as of March 30, 2006 (the "Agreement") among the Depositor, Wells Fargo Bank,
N.A., as master servicer (the "Master Servicer") and U.S. Bank National
Association, as trustee (the "Trustee"), a summary of certain of the pertinent
provisions of which is set forth hereinafter. To the extent not defined herein,
the capitalized terms used herein have the meanings ascribed to such terms in
the Agreement. This Certificate is issued under and is subject to the terms,
provisions and conditions of the Agreement, to which Agreement the Holder of
this Certificate by virtue of the acceptance hereof assents and by which such
Holder is bound.

      Pursuant to the terms of the Agreement, a distribution will be made on the
25th day of each month or, if such 25th day is not a Business Day, the Business
Day immediately following (the "Distribution Date"), commencing on the first
Distribution Date specified above, to the Person in whose name this Certificate
is registered at the close of business on the Record Date, in an amount equal to
the product of the Percentage Interest evidenced by this Certificate and the
Group I-A Distribution Amount for the Class I-A-5 Certificates required to be
distributed to Holders of the Class I-A-5 Certificates on such Distribution
Date, subject to adjustment in certain events as specified in the Agreement.
Distributions in reduction of the Principal Balance of certain Classes of Class
A Certificates may not commence on the first Distribution Date specified above.
Distributions of principal will be allocated among the Classes of Group I-A
Certificates in accordance with the provisions of the Agreement. The
pass-through rate applicable with respect to the Distribution Date in April 2006
will be 5.420% per annum. Thereafter, the pass-through rate on the Class I-A-5
Certificates applicable to each Distribution Date will be a floating rate of
interest determined as specified in the Agreement. The amount of interest which
accrues on this Certificate in any month will be subject to reduction with
respect to any Non-Supported Interest Shortfall, any Relief Act Shortfall and
the interest portion of certain Realized Losses allocated to the Class I-A-5
Certificates, as described in the Agreement.

      Distributions on this Certificate will be made by the Paying Agent by
check mailed to the address of the Person entitled thereto, as such name and
address shall appear on the Certificate Register, unless such Person is entitled
to receive payments by wire transfer in immediately available funds in
accordance with the Agreement and such Person has notified the Paying Agent
pursuant to the Agreement that such payments are to be made by wire transfer of
immediately available funds. Notwithstanding the above, the final distribution
in reduction of the Principal Balance of this Certificate will be made after due
notice of the pendency of such distribution and only upon presentation and
surrender of this Certificate at the office or agency of the Paying Agent
specified for that purpose in the notice of final distribution.

      Reference is hereby made to the further provisions of this Certificate set
forth on the reverse hereof, which further provisions shall for all purposes
have the same effect as if set forth at this place.

      This Certificate constitutes a "regular interest" in a "real estate
mortgage investment conduit" as those terms are defined in Section 860G(a)(1)
and Section 860D, respectively, of the Internal Revenue Code of 1986, as
amended, and certain other property.

      Unless this Certificate has been countersigned by an authorized officer of
the Authenticating Agent, by manual signature, this Certificate shall not be
entitled to any benefit under the Agreement or be valid for any purpose.


<PAGE>

      IN WITNESS WHEREOF, the Paying Agent has caused this Certificate to be
duly executed as of the date set forth below.

Dated:

                                       Wells Fargo Bank, N.A.,
                                            Paying Agent

                                       By____________________________
                                            Authorized Officer

Countersigned:

Wells Fargo Bank, N.A.,
  Authenticating Agent

By ________________________
   Authorized Officer


<PAGE>

                                 EXHIBIT A-I-A-6
                    [FORM OF FACE OF CLASS I-A-6 CERTIFICATE]

  [UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE
   DEPOSITORY TRUST COMPANY TO THE DEPOSITOR OR ITS AGENT FOR REGISTRATION OF
 TRANSFER, EXCHANGE OR PAYMENT, AND ANY CERTIFICATE ISSUED IS REGISTERED IN THE
       NAME OF CEDE & CO. OR SUCH OTHER NAME AS REQUESTED BY AN AUTHORIZED
REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY AND ANY PAYMENT IS MADE TO CEDE &
  CO., ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO
  ANY PERSON IS WRONGFUL SINCE THE REGISTERED OWNER HEREOF, CEDE & CO., HAS AN
                                INTEREST HEREIN.]

                        MORTGAGE PASS-THROUGH CERTIFICATE
                           SERIES 2006-4, CLASS I-A-6

                    evidencing an interest in a pool of fixed
                           interest rate, monthly pay,
                      fully amortizing, first lien, one- to
                 four-family residential mortgage loans sold by

                    WELLS FARGO ASSET SECURITIES CORPORATION
               (Not an interest in or obligation of the Depositor)

            THIS CERTIFICATE DOES NOT EVIDENCE AN OBLIGATION OF, OR AN INTEREST
IN, THE DEPOSITOR, THE MASTER SERVICER, THE TRUSTEE OR ANY OF THEIR AFFILIATES,
AND IS NOT INSURED OR GUARANTEED BY THE DEPOSITOR, THE MASTER SERVICER, THE
TRUSTEE OR ANY OF THEIR AFFILIATES, OR BY ANY GOVERNMENT AGENCY OR PRIVATE
INSURER.

            REDUCTION OF THE NOTIONAL AMOUNT OF THIS CERTIFICATE WILL BE MADE IN
THE MANNER DESCRIBED IN THE AGREEMENT. ACCORDINGLY, THE OUTSTANDING NOTIONAL
AMOUNT OF THIS CERTIFICATE AT ANY TIME MAY BE LESS THAN THE INITIAL NOTIONAL
AMOUNT REPRESENTED HEREBY.

Certificate No.                        Cut-Off Date:  March 1, 2006

CUSIP No.:  94983B AF 6                First Distribution Date: April 25, 2006

ISIN No.: US94983BAF67                 Denomination:  $

Percentage Interest evidenced          Final Scheduled Maturity Date:  April 25,
by this Certificate: %                 2036


      THIS CERTIFIES THAT ___________________________ is the registered owner of
the Percentage Interest evidenced by this Certificate in monthly distributions
to the Holders of the Class I-A-6 Certificates with respect to a Trust Estate
consisting of a pool of fixed interest rate, monthly pay, fully amortizing,
first lien, one- to four-family residential mortgage loans, other than the Fixed
Retained Yield, if any, with respect thereto, consisting of two loan groups (the
"Group I Mortgage Loans" and "Group II Mortgage Loans," respectively), formed by
Wells Fargo Asset Securities Corporation (hereinafter called the "Depositor,"
which term includes any successor entity under the Agreement referred to below).
The Trust Estate was created pursuant to a Pooling and Servicing Agreement dated
as of March 30, 2006 (the "Agreement") among the Depositor, Wells Fargo Bank,
N.A., as master servicer (the "Master Servicer") and U.S. Bank National
Association, as trustee (the "Trustee"), a summary of certain of the pertinent
provisions of which is set forth hereinafter. To the extent not defined herein,
the capitalized terms used herein have the meanings ascribed to such terms in
the Agreement. This Certificate is issued under and is subject to the terms,
provisions and conditions of the Agreement, to which Agreement the Holder of
this Certificate by virtue of the acceptance hereof assents and by which such
Holder is bound.

      Pursuant to the terms of the Agreement, a distribution will be made on the
25th day of each month or, if such 25th day is not a Business Day, the Business
Day immediately following (the "Distribution Date"), commencing on the first
Distribution Date specified above, to the Person in whose name this Certificate
is registered at the close of business on the Record Date, in an amount equal to
the product of the Percentage Interest evidenced by this Certificate and the
Group I-A Distribution Amount for the Class I-A-6 Certificates required to be
distributed to Holders of the Class I-A-6 Certificates on such Distribution
Date, subject to adjustment in certain events as specified in the Agreement. The
Class I-A-6 Certificates are not entitled to distribution in respect of
principal. The pass-through rate applicable with respect to the Distribution
Date in April 2006 will be 0.330% per annum. Thereafter, the pass-through rate
on the Class I-A-6 Certificates applicable to each Distribution Date will be an
inverse floating rate of interest determined as specified in the Agreement. The
amount of interest which accrues on this Certificate in any month will be
subject to reduction with respect to any Non-Supported Interest Shortfall, any
Relief Act Shortfall and the interest portion of certain Realized Losses
allocated to the Class I-A-6 Certificates, as described in the Agreement.

      Distributions on this Certificate will be made by the Paying Agent by
check mailed to the address of the Person entitled thereto, as such name and
address shall appear on the Certificate Register, unless such Person is entitled
to receive payments by wire transfer in immediately available funds in
accordance with the Agreement and such Person has notified the Paying Agent
pursuant to the Agreement that such payments are to be made by wire transfer of
immediately available funds. Notwithstanding the above, the final distribution
on this Certificate will be made after due notice of the pendency of such
distribution and only upon presentation and surrender of this Certificate at the
office or agency of the Paying Agent specified for that purpose in the notice of
final distribution.

      Reference is hereby made to the further provisions of this Certificate set
forth on the reverse hereof, which further provisions shall for all purposes
have the same effect as if set forth at this place.

      This Certificate constitutes a "regular interest" in a "real estate
mortgage investment conduit" as those terms are defined in Section 860G(a)(1)
and Section 860D, respectively, of the Internal Revenue Code of 1986, as
amended.

      Unless this Certificate has been countersigned by an authorized officer of
the Authenticating Agent, by manual signature, this Certificate shall not be
entitled to any benefit under the Agreement or be valid for any purpose.


<PAGE>

      IN WITNESS WHEREOF, the Paying Agent has caused this Certificate to be
duly executed as of the date set forth below.

Dated:

                                       Wells Fargo Bank, N.A.,
                                            Paying Agent

                                       By____________________________
                                            Authorized Officer

Countersigned:

Wells Fargo Bank, N.A.,
  Authenticating Agent

By ________________________
   Authorized Officer


<PAGE>

                                 EXHIBIT A-I-A-7
                    [FORM OF FACE OF CLASS I-A-7 CERTIFICATE]

  [UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE
   DEPOSITORY TRUST COMPANY TO THE DEPOSITOR OR ITS AGENT FOR REGISTRATION OF
   TRANSFER, EXCHANGE OR PAYMENT, AND ANY CERTIFICATE ISSUED IS REGISTERED IN
     THE NAME OF CEDE & CO. OR SUCH OTHER NAME AS REQUESTED BY AN AUTHORIZED
    REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY AND ANY PAYMENT IS MADE TO
   CEDE & CO., ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE
    BY OR TO ANY PERSON IS WRONGFUL SINCE THE REGISTERED OWNER HEREOF, CEDE &
                          CO., HAS AN INTEREST HEREIN.]

                        MORTGAGE PASS-THROUGH CERTIFICATE
                           SERIES 2006-4, CLASS I-A-7

                    evidencing an interest in a pool of fixed
                           interest rate, monthly pay,
                      fully amortizing, first lien, one- to
                 four-family residential mortgage loans sold by

                    WELLS FARGO ASSET SECURITIES CORPORATION
               (Not an interest in or obligation of the Depositor)

            THIS CERTIFICATE DOES NOT EVIDENCE AN OBLIGATION OF, OR AN INTEREST
IN, THE DEPOSITOR, THE MASTER SERVICER, THE TRUSTEE OR ANY OF THEIR AFFILIATES,
AND IS NOT INSURED OR GUARANTEED BY THE DEPOSITOR, THE MASTER SERVICER, THE
TRUSTEE OR ANY OF THEIR AFFILIATES, OR BY ANY GOVERNMENT AGENCY OR PRIVATE
INSURER.

            UNTIL THE APPLICABLE ACCRETION TERMINATION DATE, THE INTEREST THAT
ACCRUES ON THE PRINCIPAL BALANCE OF THIS CERTIFICATE WILL NOT BE PAYABLE BECAUSE
SUCH UNPAID INTEREST IS ADDED TO THE PRINCIPAL BALANCE OF THIS CERTIFICATE AND
BECAUSE DISTRIBUTIONS IN REDUCTION OF THE PRINCIPAL BALANCE WILL BE MADE IN THE
MANNER DESCRIBED IN THE AGREEMENT, THE OUTSTANDING PRINCIPAL BALANCE OF THIS
CERTIFICATE AT ANY TIME MAY BE MORE OR LESS THAN THE INITIAL PRINCIPAL BALANCE
REPRESENTED HEREBY.

Certificate No.                        Cut-Off Date:  March 1, 2006

CUSIP No.: 94983B AG 4                 First Distribution Date: April 25, 2006

ISIN No.: US94983BAG41                 Denomination:  $

Percentage Interest evidenced          Final Scheduled Maturity Date:  April 25,
by this Certificate: %                 2036


      THIS CERTIFIES THAT ___________________________ is the registered owner of
the Percentage Interest evidenced by this Certificate in monthly distributions
to the Holders of the Class I-A-7 Certificates with respect to a Trust Estate
consisting of a pool of fixed interest rate, monthly pay, fully amortizing,
first lien, one- to four-family residential mortgage loans, other than the Fixed
Retained Yield, if any, with respect thereto, consisting of two loan groups (the
"Group I Mortgage Loans" and "Group II Mortgage Loans," respectively), formed by
Wells Fargo Asset Securities Corporation (hereinafter called the "Depositor,"
which term includes any successor entity under the Agreement referred to below).
The Trust Estate was created pursuant to a Pooling and Servicing Agreement dated
as of March 30, 2006 (the "Agreement") among the Depositor, Wells Fargo Bank,
N.A., as master servicer (the "Master Servicer") and U.S. Bank National
Association, as trustee (the "Trustee"), a summary of certain of the pertinent
provisions of which is set forth hereinafter. To the extent not defined herein,
the capitalized terms used herein have the meanings ascribed to such terms in
the Agreement. This Certificate is issued under and is subject to the terms,
provisions and conditions of the Agreement, to which Agreement the Holder of
this Certificate by virtue of the acceptance hereof assents and by which such
Holder is bound.

      Pursuant to the terms of the Agreement, a distribution will be made on the
25th day of each month or, if such 25th day is not a Business Day, the Business
Day immediately following (the "Distribution Date"), commencing on the first
Distribution Date specified above, to the Person in whose name this Certificate
is registered at the close of business on the Record Date, in an amount equal to
the product of the Percentage Interest evidenced by this Certificate and the
Group I-A Distribution Amount for the Class I-A-7 Certificates required to be
distributed to Holders of the Class I-A-7 Certificates on such Distribution
Date, subject to adjustment in certain events as specified in the Agreement.
Distributions in reduction of the Principal Balance of certain Classes of Class
A Certificates may not commence on the first Distribution Date specified above.
Distributions of principal will be allocated among the Classes of Group I-A
Certificates in accordance with the provisions of the Agreement. Prior to the
applicable Accretion Termination Date, no distribution of interest on this
Certificate will be made. Prior to the applicable Accretion Termination Date,
interest otherwise available for distribution on this Certificate will be added
to the Principal Balance of the Class I-A-7 Certificates on each Distribution
Date. The pass-through rate on the Class I-A-7 Certificates applicable to each
Distribution Date will be 5.750% per annum. The amount of interest which accrues
on this Certificate in any month will be subject to reduction with respect to
any Non-Supported Interest Shortfall, any Relief Act Shortfall and the interest
portion of certain Realized Losses allocated to the Class I-A-7 Certificates, as
described in the Agreement.

      Distributions on this Certificate will be made by the Paying Agent by
check mailed to the address of the Person entitled thereto, as such name and
address shall appear on the Certificate Register, unless such Person is entitled
to receive payments by wire transfer in immediately available funds in
accordance with the Agreement and such Person has notified the Paying Agent
pursuant to the Agreement that such payments are to be made by wire transfer of
immediately available funds. Notwithstanding the above, the final distribution
in reduction of the Principal Balance of this Certificate will be made after due
notice of the pendency of such distribution and only upon presentation and
surrender of this Certificate at the office or agency of the Paying Agent
specified for that purpose in the notice of final distribution.

      Reference is hereby made to the further provisions of this Certificate set
forth on the reverse hereof, which further provisions shall for all purposes
have the same effect as if set forth at this place.

      This Certificate constitutes a "regular interest" in a "real estate
mortgage investment conduit" as those terms are defined in Section 860G(a)(1)
and Section 860D, respectively, of the Internal Revenue Code of 1986, as
amended.

      Unless this Certificate has been countersigned by an authorized officer of
the Authenticating Agent, by manual signature, this Certificate shall not be
entitled to any benefit under the Agreement or be valid for any purpose.


<PAGE>

      IN WITNESS WHEREOF, the Paying Agent has caused this Certificate to be
duly executed as of the date set forth below.

Dated:

                                       Wells Fargo Bank, N.A.,
                                            Paying Agent

                                       By____________________________
                                            Authorized Officer

Countersigned:

Wells Fargo Bank, N.A.,
  Authenticating Agent

By ________________________
   Authorized Officer


<PAGE>

                                 EXHIBIT A-I-A-8
                    [FORM OF FACE OF CLASS I-A-8 CERTIFICATE]

  [UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE
   DEPOSITORY TRUST COMPANY TO THE DEPOSITOR OR ITS AGENT FOR REGISTRATION OF
 TRANSFER, EXCHANGE OR PAYMENT, AND ANY CERTIFICATE ISSUED IS REGISTERED IN THE
       NAME OF CEDE & CO. OR SUCH OTHER NAME AS REQUESTED BY AN AUTHORIZED
REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY AND ANY PAYMENT IS MADE TO CEDE &
  CO., ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO
  ANY PERSON IS WRONGFUL SINCE THE REGISTERED OWNER HEREOF, CEDE & CO., HAS AN
                                INTEREST HEREIN.]

                        MORTGAGE PASS-THROUGH CERTIFICATE
                           SERIES 2006-4, CLASS I-A-8

                    evidencing an interest in a pool of fixed
                           interest rate, monthly pay,
                      fully amortizing, first lien, one- to
                 four-family residential mortgage loans sold by

                    WELLS FARGO ASSET SECURITIES CORPORATION
               (Not an interest in or obligation of the Depositor)

            THIS CERTIFICATE DOES NOT EVIDENCE AN OBLIGATION OF, OR AN INTEREST
IN, THE DEPOSITOR, THE MASTER SERVICER, THE TRUSTEE OR ANY OF THEIR AFFILIATES,
AND IS NOT INSURED OR GUARANTEED BY THE DEPOSITOR, THE MASTER SERVICER, THE
TRUSTEE OR ANY OF THEIR AFFILIATES, OR BY ANY GOVERNMENT AGENCY OR PRIVATE
INSURER.

            DISTRIBUTIONS IN REDUCTION OF THE PRINCIPAL BALANCE OF THIS
CERTIFICATE WILL BE MADE IN THE MANNER DESCRIBED IN THE AGREEMENT. ACCORDINGLY,
THE OUTSTANDING PRINCIPAL BALANCE OF THIS CERTIFICATE AT ANY TIME MAY BE LESS
THAN THE INITIAL PRINCIPAL BALANCE REPRESENTED HEREBY.

Certificate No.                        Cut-Off Date:  March 1, 2006

CUSIP No.: 94983B AH 2                 First Distribution Date: April 25, 2006

ISIN No.: US94983BAH24                 Denomination:  $

Percentage Interest evidenced          Final Scheduled Maturity Date:  April 25,
by this Certificate: %                 2036


      THIS CERTIFIES THAT ___________________________ is the registered owner of
the Percentage Interest evidenced by this Certificate in monthly distributions
to the Holders of the Class I-A-8 Certificates with respect to a Trust Estate
consisting of a pool of fixed interest rate, monthly pay, fully amortizing,
first lien, one- to four-family residential mortgage loans, other than the Fixed
Retained Yield, if any, with respect thereto, consisting of two loan groups (the
"Group I Mortgage Loans" and "Group II Mortgage Loans," respectively), formed by
Wells Fargo Asset Securities Corporation (hereinafter called the "Depositor,"
which term includes any successor entity under the Agreement referred to below).
The Trust Estate was created pursuant to a Pooling and Servicing Agreement dated
as of March 30, 2006 (the "Agreement") among the Depositor, Wells Fargo Bank,
N.A., as master servicer (the "Master Servicer") and U.S. Bank National
Association, as trustee (the "Trustee"), a summary of certain of the pertinent
provisions of which is set forth hereinafter. To the extent not defined herein,
the capitalized terms used herein have the meanings ascribed to such terms in
the Agreement. This Certificate is issued under and is subject to the terms,
provisions and conditions of the Agreement, to which Agreement the Holder of
this Certificate by virtue of the acceptance hereof assents and by which such
Holder is bound.

      Pursuant to the terms of the Agreement, a distribution will be made on the
25th day of each month or, if such 25th day is not a Business Day, the Business
Day immediately following (the "Distribution Date"), commencing on the first
Distribution Date specified above, to the Person in whose name this Certificate
is registered at the close of business on the Record Date, in an amount equal to
the product of the Percentage Interest evidenced by this Certificate and the
Group I-A Distribution Amount for the Class I-A-8 Certificates required to be
distributed to Holders of the Class I-A-8 Certificates on such Distribution
Date, subject to adjustment in certain events as specified in the Agreement.
Distributions in reduction of the Principal Balance of certain Classes of Class
A Certificates may not commence on the first Distribution Date specified above.
Distributions of principal will be allocated among the Classes of Group I-A
Certificates in accordance with the provisions of the Agreement. The
pass-through rate on the Class I-A-8 Certificates applicable to each
Distribution Date will be 5.750% per annum. The amount of interest which accrues
on this Certificate in any month will be subject to reduction with respect to
any Non-Supported Interest Shortfall, any Relief Act Shortfall and the interest
portion of certain Realized Losses allocated to the Class I-A-8 Certificates, as
described in the Agreement.

      Distributions on this Certificate will be made by the Paying Agent by
check mailed to the address of the Person entitled thereto, as such name and
address shall appear on the Certificate Register, unless such Person is entitled
to receive payments by wire transfer in immediately available funds in
accordance with the Agreement and such Person has notified the Paying Agent
pursuant to the Agreement that such payments are to be made by wire transfer of
immediately available funds. Notwithstanding the above, the final distribution
in reduction of the Principal Balance of this Certificate will be made after due
notice of the pendency of such distribution and only upon presentation and
surrender of this Certificate at the office or agency of the Paying Agent
specified for that purpose in the notice of final distribution.

      Reference is hereby made to the further provisions of this Certificate set
forth on the reverse hereof, which further provisions shall for all purposes
have the same effect as if set forth at this place.

      This Certificate constitutes a "regular interest" in a "real estate
mortgage investment conduit" as those terms are defined in Section 860G(a)(1)
and Section 860D, respectively, of the Internal Revenue Code of 1986, as
amended.

      Unless this Certificate has been countersigned by an authorized officer of
the Authenticating Agent, by manual signature, this Certificate shall not be
entitled to any benefit under the Agreement or be valid for any purpose.


<PAGE>

      IN WITNESS WHEREOF, the Paying Agent has caused this Certificate to be
duly executed as of the date set forth below.

Dated:

                                       Wells Fargo Bank, N.A.,
                                            Paying Agent

                                       By____________________________
                                            Authorized Officer

Countersigned:

Wells Fargo Bank, N.A.,
  Authenticating Agent

By ________________________
   Authorized Officer


<PAGE>

                                 EXHIBIT A-I-A-9
                    [FORM OF FACE OF CLASS I-A-9 CERTIFICATE]

  [UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE
   DEPOSITORY TRUST COMPANY TO THE DEPOSITOR OR ITS AGENT FOR REGISTRATION OF
 TRANSFER, EXCHANGE OR PAYMENT, AND ANY CERTIFICATE ISSUED IS REGISTERED IN THE
       NAME OF CEDE & CO. OR SUCH OTHER NAME AS REQUESTED BY AN AUTHORIZED
REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY AND ANY PAYMENT IS MADE TO CEDE &
  CO., ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO
  ANY PERSON IS WRONGFUL SINCE THE REGISTERED OWNER HEREOF, CEDE & CO., HAS AN
                                INTEREST HEREIN.]

                        MORTGAGE PASS-THROUGH CERTIFICATE
                           SERIES 2006-4, CLASS I-A-9

                    evidencing an interest in a pool of fixed
                           interest rate, monthly pay,
                      fully amortizing, first lien, one- to
                 four-family residential mortgage loans sold by

                    WELLS FARGO ASSET SECURITIES CORPORATION
               (Not an interest in or obligation of the Depositor)

            THIS CERTIFICATE DOES NOT EVIDENCE AN OBLIGATION OF, OR AN INTEREST
IN, THE DEPOSITOR, THE MASTER SERVICER, THE TRUSTEE OR ANY OF THEIR AFFILIATES,
AND IS NOT INSURED OR GUARANTEED BY THE DEPOSITOR, THE MASTER SERVICER, THE
TRUSTEE OR ANY OF THEIR AFFILIATES, OR BY ANY GOVERNMENT AGENCY OR PRIVATE
INSURER.

            DISTRIBUTIONS IN REDUCTION OF THE PRINCIPAL BALANCE OF THIS
CERTIFICATE WILL BE MADE IN THE MANNER DESCRIBED IN THE AGREEMENT. ACCORDINGLY,
THE OUTSTANDING PRINCIPAL BALANCE OF THIS CERTIFICATE AT ANY TIME MAY BE LESS
THAN THE INITIAL PRINCIPAL BALANCE REPRESENTED HEREBY.

Certificate No.                        Cut-Off Date:  March 1, 2006

CUSIP No.: 94983B AJ 8                 First Distribution Date: April 25, 2006

ISIN No.: US94983BAJ89                 Denomination:  $

Percentage Interest evidenced          Final Scheduled Maturity Date:  April 25,
by this Certificate: %                 2036


      THIS CERTIFIES THAT ___________________________ is the registered owner of
the Percentage Interest evidenced by this Certificate in monthly distributions
to the Holders of the Class I-A-9 Certificates with respect to a Trust Estate
consisting of a pool of fixed interest rate, monthly pay, fully amortizing,
first lien, one- to four-family residential mortgage loans, other than the Fixed
Retained Yield, if any, with respect thereto, consisting of two loan groups (the
"Group I Mortgage Loans" and "Group II Mortgage Loans," respectively), formed by
Wells Fargo Asset Securities Corporation (hereinafter called the "Depositor,"
which term includes any successor entity under the Agreement referred to below).
The Trust Estate was created pursuant to a Pooling and Servicing Agreement dated
as of March 30, 2006 (the "Agreement") among the Depositor, Wells Fargo Bank,
N.A., as master servicer (the "Master Servicer") and U.S. Bank National
Association, as trustee (the "Trustee"), a summary of certain of the pertinent
provisions of which is set forth hereinafter. To the extent not defined herein,
the capitalized terms used herein have the meanings ascribed to such terms in
the Agreement. This Certificate is issued under and is subject to the terms,
provisions and conditions of the Agreement, to which Agreement the Holder of
this Certificate by virtue of the acceptance hereof assents and by which such
Holder is bound.

      Pursuant to the terms of the Agreement, a distribution will be made on the
25th day of each month or, if such 25th day is not a Business Day, the Business
Day immediately following (the "Distribution Date"), commencing on the first
Distribution Date specified above, to the Person in whose name this Certificate
is registered at the close of business on the Record Date, in an amount equal to
the product of the Percentage Interest evidenced by this Certificate and the
Group I-A Distribution Amount for the Class I-A-9 Certificates required to be
distributed to Holders of the Class I-A-9 Certificates on such Distribution
Date, subject to adjustment in certain events as specified in the Agreement.
Distributions in reduction of the Principal Balance of certain Classes of Class
A Certificates may not commence on the first Distribution Date specified above.
Distributions of principal will be allocated among the Classes of Group I-A
Certificates in accordance with the provisions of the Agreement. The
pass-through rate on the Class I-A-9 Certificates applicable to each
Distribution Date will be 5.750% per annum. The amount of interest which accrues
on this Certificate in any month will be subject to reduction with respect to
any Non-Supported Interest Shortfall, any Relief Act Shortfall and the interest
portion of certain Realized Losses allocated to the Class I-A-9 Certificates, as
described in the Agreement.

      Distributions on this Certificate will be made by the Paying Agent by
check mailed to the address of the Person entitled thereto, as such name and
address shall appear on the Certificate Register, unless such Person is entitled
to receive payments by wire transfer in immediately available funds in
accordance with the Agreement and such Person has notified the Paying Agent
pursuant to the Agreement that such payments are to be made by wire transfer of
immediately available funds. Notwithstanding the above, the final distribution
in reduction of the Principal Balance of this Certificate will be made after due
notice of the pendency of such distribution and only upon presentation and
surrender of this Certificate at the office or agency of the Paying Agent
specified for that purpose in the notice of final distribution.

      Reference is hereby made to the further provisions of this Certificate set
forth on the reverse hereof, which further provisions shall for all purposes
have the same effect as if set forth at this place.

      This Certificate constitutes a "regular interest" in a "real estate
mortgage investment conduit" as those terms are defined in Section 860G(a)(1)
and Section 860D, respectively, of the Internal Revenue Code of 1986, as
amended.

      Unless this Certificate has been countersigned by an authorized officer of
the Authenticating Agent, by manual signature, this Certificate shall not be
entitled to any benefit under the Agreement or be valid for any purpose.


<PAGE>

      IN WITNESS WHEREOF, the Paying Agent has caused this Certificate to be
duly executed as of the date set forth below.

Dated:

                                       Wells Fargo Bank, N.A.,
                                            Paying Agent

                                       By____________________________
                                            Authorized Officer

Countersigned:

Wells Fargo Bank, N.A.,
  Authenticating Agent

By ________________________
   Authorized Officer


<PAGE>

                                EXHIBIT A-I-A-10
                   [FORM OF FACE OF CLASS I-A-10 CERTIFICATE]

  [UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE
   DEPOSITORY TRUST COMPANY TO THE DEPOSITOR OR ITS AGENT FOR REGISTRATION OF
 TRANSFER, EXCHANGE OR PAYMENT, AND ANY CERTIFICATE ISSUED IS REGISTERED IN THE
       NAME OF CEDE & CO. OR SUCH OTHER NAME AS REQUESTED BY AN AUTHORIZED
REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY AND ANY PAYMENT IS MADE TO CEDE &
  CO., ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO
  ANY PERSON IS WRONGFUL SINCE THE REGISTERED OWNER HEREOF, CEDE & CO., HAS AN
                                INTEREST HEREIN.]

                        MORTGAGE PASS-THROUGH CERTIFICATE
                           SERIES 2006-4, CLASS I-A-10

                    evidencing an interest in a pool of fixed
                           interest rate, monthly pay,
                      fully amortizing, first lien, one- to
                 four-family residential mortgage loans sold by

                    WELLS FARGO ASSET SECURITIES CORPORATION
               (Not an interest in or obligation of the Depositor)

            THIS CERTIFICATE DOES NOT EVIDENCE AN OBLIGATION OF, OR AN INTEREST
IN, THE DEPOSITOR, THE MASTER SERVICER, THE TRUSTEE OR ANY OF THEIR AFFILIATES,
AND IS NOT INSURED OR GUARANTEED BY THE DEPOSITOR, THE MASTER SERVICER, THE
TRUSTEE OR ANY OF THEIR AFFILIATES, OR BY ANY GOVERNMENT AGENCY OR PRIVATE
INSURER.

            UNTIL THE APPLICABLE ACCRETION TERMINATION DATE, THE INTEREST THAT
ACCRUES ON THE PRINCIPAL BALANCE OF THIS CERTIFICATE WILL NOT BE PAYABLE BECAUSE
SUCH UNPAID INTEREST IS ADDED TO THE PRINCIPAL BALANCE OF THIS CERTIFICATE AND
BECAUSE DISTRIBUTIONS IN REDUCTION OF THE PRINCIPAL BALANCE WILL BE MADE IN THE
MANNER DESCRIBED IN THE AGREEMENT, THE OUTSTANDING PRINCIPAL BALANCE OF THIS
CERTIFICATE AT ANY TIME MAY BE MORE OR LESS THAN THE INITIAL PRINCIPAL BALANCE
REPRESENTED HEREBY.

Certificate No.                        Cut-Off Date:  March 1, 2006

CUSIP No.: 94983B AK 5                 First Distribution Date: April 25, 2006

ISIN No.: US94983BAK52                 Denomination:  $

Percentage Interest evidenced          Final Scheduled Maturity Date:  April 25,
by this Certificate: %                 2036


      THIS CERTIFIES THAT ___________________________ is the registered owner of
the Percentage Interest evidenced by this Certificate in monthly distributions
to the Holders of the Class I-A-10 Certificates with respect to a Trust Estate
consisting of a pool of fixed interest rate, monthly pay, fully amortizing,
first lien, one- to four-family residential mortgage loans, other than the Fixed
Retained Yield, if any, with respect thereto, consisting of two loan groups (the
"Group I Mortgage Loans" and "Group II Mortgage Loans," respectively), formed by
Wells Fargo Asset Securities Corporation (hereinafter called the "Depositor,"
which term includes any successor entity under the Agreement referred to below).
The Trust Estate was created pursuant to a Pooling and Servicing Agreement dated
as of March 30, 2006 (the "Agreement") among the Depositor, Wells Fargo Bank,
N.A., as master servicer (the "Master Servicer") and U.S. Bank National
Association, as trustee (the "Trustee"), a summary of certain of the pertinent
provisions of which is set forth hereinafter. To the extent not defined herein,
the capitalized terms used herein have the meanings ascribed to such terms in
the Agreement. This Certificate is issued under and is subject to the terms,
provisions and conditions of the Agreement, to which Agreement the Holder of
this Certificate by virtue of the acceptance hereof assents and by which such
Holder is bound.

      Pursuant to the terms of the Agreement, a distribution will be made on the
25th day of each month or, if such 25th day is not a Business Day, the Business
Day immediately following (the "Distribution Date"), commencing on the first
Distribution Date specified above, to the Person in whose name this Certificate
is registered at the close of business on the Record Date, in an amount equal to
the product of the Percentage Interest evidenced by this Certificate and the
Group I-A Distribution Amount for the Class I-A-10 Certificates required to be
distributed to Holders of the Class I-A-10 Certificates on such Distribution
Date, subject to adjustment in certain events as specified in the Agreement.
Distributions in reduction of the Principal Balance of certain Classes of Class
A Certificates may not commence on the first Distribution Date specified above.
Distributions of principal will be allocated among the Classes of Group I-A
Certificates in accordance with the provisions of the Agreement. Prior to the
applicable Accretion Termination Date, no distribution of interest on this
Certificate will be made. Prior to the applicable Accretion Termination Date,
interest otherwise available for distribution on this Certificate will be added
to the Principal Balance of the Class I-A-10 Certificates on each Distribution
Date. The pass-through rate on the Class I-A-10 Certificates applicable to each
Distribution Date will be 5.750% per annum. The amount of interest which accrues
on this Certificate in any month will be subject to reduction with respect to
any Non-Supported Interest Shortfall, any Relief Act Shortfall and the interest
portion of certain Realized Losses allocated to the Class I-A-10 Certificates,
as described in the Agreement.

      Distributions on this Certificate will be made by the Paying Agent by
check mailed to the address of the Person entitled thereto, as such name and
address shall appear on the Certificate Register, unless such Person is entitled
to receive payments by wire transfer in immediately available funds in
accordance with the Agreement and such Person has notified the Paying Agent
pursuant to the Agreement that such payments are to be made by wire transfer of
immediately available funds. Notwithstanding the above, the final distribution
in reduction of the Principal Balance of this Certificate will be made after due
notice of the pendency of such distribution and only upon presentation and
surrender of this Certificate at the office or agency of the Paying Agent
specified for that purpose in the notice of final distribution.

      Reference is hereby made to the further provisions of this Certificate set
forth on the reverse hereof, which further provisions shall for all purposes
have the same effect as if set forth at this place.

      This Certificate constitutes a "regular interest" in a "real estate
mortgage investment conduit" as those terms are defined in Section 860G(a)(1)
and Section 860D, respectively, of the Internal Revenue Code of 1986, as
amended.

      Unless this Certificate has been countersigned by an authorized officer of
the Authenticating Agent, by manual signature, this Certificate shall not be
entitled to any benefit under the Agreement or be valid for any purpose.


<PAGE>

      IN WITNESS WHEREOF, the Paying Agent has caused this Certificate to be
duly executed as of the date set forth below.

Dated:

                                       Wells Fargo Bank, N.A.,
                                            Paying Agent

                                       By____________________________
                                            Authorized Officer

Countersigned:

Wells Fargo Bank, N.A.,
  Authenticating Agent

By ________________________
   Authorized Officer


<PAGE>

                                EXHIBIT A-I-A-11
                   [FORM OF FACE OF CLASS I-A-11 CERTIFICATE]

  [UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE
   DEPOSITORY TRUST COMPANY TO THE DEPOSITOR OR ITS AGENT FOR REGISTRATION OF
 TRANSFER, EXCHANGE OR PAYMENT, AND ANY CERTIFICATE ISSUED IS REGISTERED IN THE
       NAME OF CEDE & CO. OR SUCH OTHER NAME AS REQUESTED BY AN AUTHORIZED
REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY AND ANY PAYMENT IS MADE TO CEDE &
  CO., ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO
  ANY PERSON IS WRONGFUL SINCE THE REGISTERED OWNER HEREOF, CEDE & CO., HAS AN
                                INTEREST HEREIN.]

                        MORTGAGE PASS-THROUGH CERTIFICATE
                           SERIES 2006-4, CLASS I-A-11

                    evidencing an interest in a pool of fixed
                           interest rate, monthly pay,
                      fully amortizing, first lien, one- to
                 four-family residential mortgage loans sold by

                    WELLS FARGO ASSET SECURITIES CORPORATION
               (Not an interest in or obligation of the Depositor)

            THIS CERTIFICATE DOES NOT EVIDENCE AN OBLIGATION OF, OR AN INTEREST
IN, THE DEPOSITOR, THE MASTER SERVICER, THE TRUSTEE OR ANY OF THEIR AFFILIATES,
AND IS NOT INSURED OR GUARANTEED BY THE DEPOSITOR, THE MASTER SERVICER, THE
TRUSTEE OR ANY OF THEIR AFFILIATES, OR BY ANY GOVERNMENT AGENCY OR PRIVATE
INSURER.

            DISTRIBUTIONS IN REDUCTION OF THE PRINCIPAL BALANCE OF THIS
CERTIFICATE WILL BE MADE IN THE MANNER DESCRIBED IN THE AGREEMENT. ACCORDINGLY,
THE OUTSTANDING PRINCIPAL BALANCE OF THIS CERTIFICATE AT ANY TIME MAY BE LESS
THAN THE INITIAL PRINCIPAL BALANCE REPRESENTED HEREBY.

Certificate No.                        Cut-Off Date:  March 1, 2006

CUSIP No.: 94983B AL 3                 First Distribution Date: April 25, 2006

ISIN No.: US94983BAL36                 Denomination:  $

Percentage Interest evidenced          Final Scheduled Maturity Date:  April 25,
by this Certificate: %                 2036


      THIS CERTIFIES THAT ___________________________ is the registered owner of
the Percentage Interest evidenced by this Certificate in monthly distributions
to the Holders of the Class I-A-11 Certificates with respect to a Trust Estate
consisting of a pool of fixed interest rate, monthly pay, fully amortizing,
first lien, one- to four-family residential mortgage loans, other than the Fixed
Retained Yield, if any, with respect thereto, consisting of two loan groups (the
"Group I Mortgage Loans" and "Group II Mortgage Loans," respectively), formed by
Wells Fargo Asset Securities Corporation (hereinafter called the "Depositor,"
which term includes any successor entity under the Agreement referred to below).
The Trust Estate was created pursuant to a Pooling and Servicing Agreement dated
as of March 30, 2006 (the "Agreement") among the Depositor, Wells Fargo Bank,
N.A., as master servicer (the "Master Servicer") and U.S. Bank National
Association, as trustee (the "Trustee"), a summary of certain of the pertinent
provisions of which is set forth hereinafter. To the extent not defined herein,
the capitalized terms used herein have the meanings ascribed to such terms in
the Agreement. This Certificate is issued under and is subject to the terms,
provisions and conditions of the Agreement, to which Agreement the Holder of
this Certificate by virtue of the acceptance hereof assents and by which such
Holder is bound.

      Pursuant to the terms of the Agreement, a distribution will be made on the
25th day of each month or, if such 25th day is not a Business Day, the Business
Day immediately following (the "Distribution Date"), commencing on the first
Distribution Date specified above, to the Person in whose name this Certificate
is registered at the close of business on the Record Date, in an amount equal to
the product of the Percentage Interest evidenced by this Certificate and the
Group I-A Distribution Amount for the Class I-A-11 Certificates required to be
distributed to Holders of the Class I-A-11 Certificates on such Distribution
Date, subject to adjustment in certain events as specified in the Agreement.
Distributions in reduction of the Principal Balance of certain Classes of Class
A Certificates may not commence on the first Distribution Date specified above.
Distributions of principal will be allocated among the Classes of Group I-A
Certificates in accordance with the provisions of the Agreement. The
pass-through rate on the Class I-A-11 Certificates applicable to each
Distribution Date will be 5.750% per annum. The amount of interest which accrues
on this Certificate in any month will be subject to reduction with respect to
any Non-Supported Interest Shortfall, any Relief Act Shortfall and the interest
portion of certain Realized Losses allocated to the Class I-A-11 Certificates,
as described in the Agreement.

      Distributions on this Certificate will be made by the Paying Agent by
check mailed to the address of the Person entitled thereto, as such name and
address shall appear on the Certificate Register, unless such Person is entitled
to receive payments by wire transfer in immediately available funds in
accordance with the Agreement and such Person has notified the Paying Agent
pursuant to the Agreement that such payments are to be made by wire transfer of
immediately available funds. Notwithstanding the above, the final distribution
in reduction of the Principal Balance of this Certificate will be made after due
notice of the pendency of such distribution and only upon presentation and
surrender of this Certificate at the office or agency of the Paying Agent
specified for that purpose in the notice of final distribution.

      Reference is hereby made to the further provisions of this Certificate set
forth on the reverse hereof, which further provisions shall for all purposes
have the same effect as if set forth at this place.

      This Certificate constitutes a "regular interest" in a "real estate
mortgage investment conduit" as those terms are defined in Section 860G(a)(1)
and Section 860D, respectively, of the Internal Revenue Code of 1986, as
amended.

      Unless this Certificate has been countersigned by an authorized officer of
the Authenticating Agent, by manual signature, this Certificate shall not be
entitled to any benefit under the Agreement or be valid for any purpose.


<PAGE>

      IN WITNESS WHEREOF, the Paying Agent has caused this Certificate to be
duly executed as of the date set forth below.

Dated:

                                       Wells Fargo Bank, N.A.,
                                            Paying Agent

                                       By____________________________
                                            Authorized Officer

Countersigned:

Wells Fargo Bank, N.A.,
  Authenticating Agent

By ________________________
   Authorized Officer


<PAGE>

                                EXHIBIT A-I-A-12
                   [FORM OF FACE OF CLASS I-A-12 CERTIFICATE]

  [UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE
   DEPOSITORY TRUST COMPANY TO THE DEPOSITOR OR ITS AGENT FOR REGISTRATION OF
 TRANSFER, EXCHANGE OR PAYMENT, AND ANY CERTIFICATE ISSUED IS REGISTERED IN THE
       NAME OF CEDE & CO. OR SUCH OTHER NAME AS REQUESTED BY AN AUTHORIZED
REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY AND ANY PAYMENT IS MADE TO CEDE &
  CO., ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO
  ANY PERSON IS WRONGFUL SINCE THE REGISTERED OWNER HEREOF, CEDE & CO., HAS AN
                                INTEREST HEREIN.]

                        MORTGAGE PASS-THROUGH CERTIFICATE
                           SERIES 2006-4, CLASS I-A-12

                    evidencing an interest in a pool of fixed
                           interest rate, monthly pay,
                      fully amortizing, first lien, one- to
                 four-family residential mortgage loans sold by

                    WELLS FARGO ASSET SECURITIES CORPORATION
               (Not an interest in or obligation of the Depositor)

            THIS CERTIFICATE DOES NOT EVIDENCE AN OBLIGATION OF, OR AN INTEREST
IN, THE DEPOSITOR, THE MASTER SERVICER, THE TRUSTEE OR ANY OF THEIR AFFILIATES,
AND IS NOT INSURED OR GUARANTEED BY THE DEPOSITOR, THE MASTER SERVICER, THE
TRUSTEE OR ANY OF THEIR AFFILIATES, OR BY ANY GOVERNMENT AGENCY OR PRIVATE
INSURER.

            DISTRIBUTIONS IN REDUCTION OF THE PRINCIPAL BALANCE OF THIS
CERTIFICATE WILL BE MADE IN THE MANNER DESCRIBED IN THE AGREEMENT. ACCORDINGLY,
THE OUTSTANDING PRINCIPAL BALANCE OF THIS CERTIFICATE AT ANY TIME MAY BE LESS
THAN THE INITIAL PRINCIPAL BALANCE REPRESENTED HEREBY.

Certificate No.                        Cut-Off Date:  March 1, 2006

CUSIP No.: 94983B AM 1                 First Distribution Date: April 25, 2006

ISIN No.: US94983BAM19                 Denomination:  $

Percentage Interest evidenced          Final Scheduled Maturity Date:  April 25,
by this Certificate: %                 2036


      THIS CERTIFIES THAT ___________________________ is the registered owner of
the Percentage Interest evidenced by this Certificate in monthly distributions
to the Holders of the Class I-A-12 Certificates with respect to a Trust Estate
consisting of a pool of fixed interest rate, monthly pay, fully amortizing,
first lien, one- to four-family residential mortgage loans, other than the Fixed
Retained Yield, if any, with respect thereto, consisting of two loan groups (the
"Group I Mortgage Loans" and "Group II Mortgage Loans," respectively), formed by
Wells Fargo Asset Securities Corporation (hereinafter called the "Depositor,"
which term includes any successor entity under the Agreement referred to below).
The Trust Estate was created pursuant to a Pooling and Servicing Agreement dated
as of March 30, 2006 (the "Agreement") among the Depositor, Wells Fargo Bank,
N.A., as master servicer (the "Master Servicer") and U.S. Bank National
Association, as trustee (the "Trustee"), a summary of certain of the pertinent
provisions of which is set forth hereinafter. To the extent not defined herein,
the capitalized terms used herein have the meanings ascribed to such terms in
the Agreement. This Certificate is issued under and is subject to the terms,
provisions and conditions of the Agreement, to which Agreement the Holder of
this Certificate by virtue of the acceptance hereof assents and by which such
Holder is bound.

      Pursuant to the terms of the Agreement, a distribution will be made on the
25th day of each month or, if such 25th day is not a Business Day, the Business
Day immediately following (the "Distribution Date"), commencing on the first
Distribution Date specified above, to the Person in whose name this Certificate
is registered at the close of business on the Record Date, in an amount equal to
the product of the Percentage Interest evidenced by this Certificate and the
Group I-A Distribution Amount for the Class I-A-12 Certificates required to be
distributed to Holders of the Class I-A-12 Certificates on such Distribution
Date, subject to adjustment in certain events as specified in the Agreement.
Distributions in reduction of the Principal Balance of certain Classes of Class
A Certificates may not commence on the first Distribution Date specified above.
Distributions of principal will be allocated among the Classes of Group I-A
Certificates in accordance with the provisions of the Agreement. The
pass-through rate on the Class I-A-12 Certificates applicable to each
Distribution Date will be 5.750% per annum. The amount of interest which accrues
on this Certificate in any month will be subject to reduction with respect to
any Non-Supported Interest Shortfall, any Relief Act Shortfall and the interest
portion of certain Realized Losses allocated to the Class I-A-12 Certificates,
as described in the Agreement.

      Distributions on this Certificate will be made by the Paying Agent by
check mailed to the address of the Person entitled thereto, as such name and
address shall appear on the Certificate Register, unless such Person is entitled
to receive payments by wire transfer in immediately available funds in
accordance with the Agreement and such Person has notified the Paying Agent
pursuant to the Agreement that such payments are to be made by wire transfer of
immediately available funds. Notwithstanding the above, the final distribution
in reduction of the Principal Balance of this Certificate will be made after due
notice of the pendency of such distribution and only upon presentation and
surrender of this Certificate at the office or agency of the Paying Agent
specified for that purpose in the notice of final distribution.

      Reference is hereby made to the further provisions of this Certificate set
forth on the reverse hereof, which further provisions shall for all purposes
have the same effect as if set forth at this place.

      This Certificate constitutes a "regular interest" in a "real estate
mortgage investment conduit" as those terms are defined in Section 860G(a)(1)
and Section 860D, respectively, of the Internal Revenue Code of 1986, as
amended.

      Unless this Certificate has been countersigned by an authorized officer of
the Authenticating Agent, by manual signature, this Certificate shall not be
entitled to any benefit under the Agreement or be valid for any purpose.


<PAGE>

      IN WITNESS WHEREOF, the Paying Agent has caused this Certificate to be
duly executed as of the date set forth below.

Dated:

                                       Wells Fargo Bank, N.A.,
                                            Paying Agent

                                       By____________________________
                                            Authorized Officer

Countersigned:

Wells Fargo Bank, N.A.,
  Authenticating Agent

By ________________________
   Authorized Officer


<PAGE>

                                EXHIBIT A-I-A-13
                   [FORM OF FACE OF CLASS I-A-13 CERTIFICATE]

  [UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE
   DEPOSITORY TRUST COMPANY TO THE DEPOSITOR OR ITS AGENT FOR REGISTRATION OF
 TRANSFER, EXCHANGE OR PAYMENT, AND ANY CERTIFICATE ISSUED IS REGISTERED IN THE
       NAME OF CEDE & CO. OR SUCH OTHER NAME AS REQUESTED BY AN AUTHORIZED
REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY AND ANY PAYMENT IS MADE TO CEDE &
  CO., ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO
  ANY PERSON IS WRONGFUL SINCE THE REGISTERED OWNER HEREOF, CEDE & CO., HAS AN
                                INTEREST HEREIN.]

                        MORTGAGE PASS-THROUGH CERTIFICATE
                           SERIES 2006-4, CLASS I-A-13

                    evidencing an interest in a pool of fixed
                           interest rate, monthly pay,
                      fully amortizing, first lien, one- to
                 four-family residential mortgage loans sold by

                    WELLS FARGO ASSET SECURITIES CORPORATION
               (Not an interest in or obligation of the Depositor)

            AFTER THE APPLICABLE SUBORDINATION DEPLETION DATE, THE PRINCIPAL
PORTION OF REALIZED LOSSES ALLOCATED TO THE CLASS I-A-2, CLASS I-A-5 AND CLASS
I-A-12 CERTIFICATES WILL BE BORNE BY THE CLASS I-A-13 CERTIFICATES AS DESCRIBED
IN THE AGREEMENT.

            THIS CERTIFICATE DOES NOT EVIDENCE AN OBLIGATION OF, OR AN INTEREST
IN, THE DEPOSITOR, THE MASTER SERVICER, THE TRUSTEE OR ANY OF THEIR AFFILIATES,
AND IS NOT INSURED OR GUARANTEED BY THE DEPOSITOR, THE MASTER SERVICER, THE
TRUSTEE OR ANY OF THEIR AFFILIATES, OR BY ANY GOVERNMENT AGENCY OR PRIVATE
INSURER.

            DISTRIBUTIONS IN REDUCTION OF THE PRINCIPAL BALANCE OF THIS
CERTIFICATE WILL BE MADE IN THE MANNER DESCRIBED IN THE AGREEMENT. ACCORDINGLY,
THE OUTSTANDING PRINCIPAL BALANCE OF THIS CERTIFICATE AT ANY TIME MAY BE LESS
THAN THE INITIAL PRINCIPAL BALANCE REPRESENTED HEREBY.

Certificate No.                        Cut-Off Date:  March 1, 2006

CUSIP No.: 94983B AN 9                 First Distribution Date: April 25, 2006

ISIN No.: US94983BAN91                 Denomination:  $

Percentage Interest evidenced          Final Scheduled Maturity Date:  April 25,
by this Certificate: %                 2036


      THIS CERTIFIES THAT ___________________________ is the registered owner of
the Percentage Interest evidenced by this Certificate in monthly distributions
to the Holders of the Class I-A-13 Certificates with respect to a Trust Estate
consisting of a pool of fixed interest rate, monthly pay, fully amortizing,
first lien, one- to four-family residential mortgage loans, other than the Fixed
Retained Yield, if any, with respect thereto, consisting of two loan groups (the
"Group I Mortgage Loans" and "Group II Mortgage Loans," respectively), formed by
Wells Fargo Asset Securities Corporation (hereinafter called the "Depositor,"
which term includes any successor entity under the Agreement referred to below).
The Trust Estate was created pursuant to a Pooling and Servicing Agreement dated
as of March 30, 2006 (the "Agreement") among the Depositor, Wells Fargo Bank,
N.A., as master servicer (the "Master Servicer") and U.S. Bank National
Association, as trustee (the "Trustee"), a summary of certain of the pertinent
provisions of which is set forth hereinafter. To the extent not defined herein,
the capitalized terms used herein have the meanings ascribed to such terms in
the Agreement. This Certificate is issued under and is subject to the terms,
provisions and conditions of the Agreement, to which Agreement the Holder of
this Certificate by virtue of the acceptance hereof assents and by which such
Holder is bound.

      Pursuant to the terms of the Agreement, a distribution will be made on the
25th day of each month or, if such 25th day is not a Business Day, the Business
Day immediately following (the "Distribution Date"), commencing on the first
Distribution Date specified above, to the Person in whose name this Certificate
is registered at the close of business on the Record Date, in an amount equal to
the product of the Percentage Interest evidenced by this Certificate and the
Group I-A Distribution Amount for the Class I-A-13 Certificates required to be
distributed to Holders of the Class I-A-13 Certificates on such Distribution
Date, subject to adjustment in certain events as specified in the Agreement.
Distributions in reduction of the Principal Balance of certain Classes of Class
A Certificates may not commence on the first Distribution Date specified above.
Distributions of principal will be allocated among the Classes of Group I-A
Certificates in accordance with the provisions of the Agreement. The
pass-through rate on the Class I-A-13 Certificates applicable to each
Distribution Date will be 5.750% per annum. The amount of interest which accrues
on this Certificate in any month will be subject to reduction with respect to
any Non-Supported Interest Shortfall, any Relief Act Shortfall and the interest
portion of certain Realized Losses allocated to the Class I-A-13 Certificates,
as described in the Agreement.

      Distributions on this Certificate will be made by the Paying Agent by
check mailed to the address of the Person entitled thereto, as such name and
address shall appear on the Certificate Register, unless such Person is entitled
to receive payments by wire transfer in immediately available funds in
accordance with the Agreement and such Person has notified the Paying Agent
pursuant to the Agreement that such payments are to be made by wire transfer of
immediately available funds. Notwithstanding the above, the final distribution
in reduction of the Principal Balance of this Certificate will be made after due
notice of the pendency of such distribution and only upon presentation and
surrender of this Certificate at the office or agency of the Paying Agent
specified for that purpose in the notice of final distribution.

      Reference is hereby made to the further provisions of this Certificate set
forth on the reverse hereof, which further provisions shall for all purposes
have the same effect as if set forth at this place.

      This Certificate constitutes a "regular interest" in a "real estate
mortgage investment conduit" as those terms are defined in Section 860G(a)(1)
and Section 860D, respectively, of the Internal Revenue Code of 1986, as
amended.

      Unless this Certificate has been countersigned by an authorized officer of
the Authenticating Agent, by manual signature, this Certificate shall not be
entitled to any benefit under the Agreement or be valid for any purpose.


<PAGE>

      IN WITNESS WHEREOF, the Paying Agent has caused this Certificate to be
duly executed as of the date set forth below.

Dated:

                                       Wells Fargo Bank, N.A.,
                                            Paying Agent

                                       By____________________________
                                            Authorized Officer

Countersigned:

Wells Fargo Bank, N.A.,
  Authenticating Agent

By ________________________
   Authorized Officer


<PAGE>

                                EXHIBIT A-I-A-14
                   [FORM OF FACE OF CLASS I-A-14 CERTIFICATE]

  [UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE
   DEPOSITORY TRUST COMPANY TO THE DEPOSITOR OR ITS AGENT FOR REGISTRATION OF
 TRANSFER, EXCHANGE OR PAYMENT, AND ANY CERTIFICATE ISSUED IS REGISTERED IN THE
       NAME OF CEDE & CO. OR SUCH OTHER NAME AS REQUESTED BY AN AUTHORIZED
REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY AND ANY PAYMENT IS MADE TO CEDE &
  CO., ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO
  ANY PERSON IS WRONGFUL SINCE THE REGISTERED OWNER HEREOF, CEDE & CO., HAS AN
                                INTEREST HEREIN.]

                        MORTGAGE PASS-THROUGH CERTIFICATE
                           SERIES 2006-4, CLASS I-A-14

                    evidencing an interest in a pool of fixed
                           interest rate, monthly pay,
                      fully amortizing, first lien, one- to
                 four-family residential mortgage loans sold by

                    WELLS FARGO ASSET SECURITIES CORPORATION
               (Not an interest in or obligation of the Depositor)

            THIS CERTIFICATE DOES NOT EVIDENCE AN OBLIGATION OF, OR AN INTEREST
IN, THE DEPOSITOR, THE MASTER SERVICER, THE TRUSTEE OR ANY OF THEIR AFFILIATES,
AND IS NOT INSURED OR GUARANTEED BY THE DEPOSITOR, THE MASTER SERVICER, THE
TRUSTEE OR ANY OF THEIR AFFILIATES, OR BY ANY GOVERNMENT AGENCY OR PRIVATE
INSURER.

            DISTRIBUTIONS IN REDUCTION OF THE PRINCIPAL BALANCE OF THIS
CERTIFICATE WILL BE MADE IN THE MANNER DESCRIBED IN THE AGREEMENT. ACCORDINGLY,
THE OUTSTANDING PRINCIPAL BALANCE OF THIS CERTIFICATE AT ANY TIME MAY BE LESS
THAN THE INITIAL PRINCIPAL BALANCE REPRESENTED HEREBY.

Certificate No.                        Cut-Off Date:  March 1, 2006

CUSIP No.: 94983B AP 4                 First Distribution Date: April 25, 2006

ISIN No.: US94983BAP40                 Denomination:  $

Percentage Interest evidenced          Final Scheduled Maturity Date:  April 25,
by this Certificate: %                 2036


      THIS CERTIFIES THAT ___________________________ is the registered owner of
the Percentage Interest evidenced by this Certificate in monthly distributions
to the Holders of the Class I-A-14 Certificates with respect to a Trust Estate
consisting of a pool of fixed interest rate, monthly pay, fully amortizing,
first lien, one- to four-family residential mortgage loans, other than the Fixed
Retained Yield, if any, with respect thereto, consisting of two loan groups (the
"Group I Mortgage Loans" and "Group II Mortgage Loans," respectively), formed by
Wells Fargo Asset Securities Corporation (hereinafter called the "Depositor,"
which term includes any successor entity under the Agreement referred to below).
The Trust Estate was created pursuant to a Pooling and Servicing Agreement dated
as of March 30, 2006 (the "Agreement") among the Depositor, Wells Fargo Bank,
N.A., as master servicer (the "Master Servicer") and U.S. Bank National
Association, as trustee (the "Trustee"), a summary of certain of the pertinent
provisions of which is set forth hereinafter. To the extent not defined herein,
the capitalized terms used herein have the meanings ascribed to such terms in
the Agreement. This Certificate is issued under and is subject to the terms,
provisions and conditions of the Agreement, to which Agreement the Holder of
this Certificate by virtue of the acceptance hereof assents and by which such
Holder is bound.

      Pursuant to the terms of the Agreement, a distribution will be made on the
25th day of each month or, if such 25th day is not a Business Day, the Business
Day immediately following (the "Distribution Date"), commencing on the first
Distribution Date specified above, to the Person in whose name this Certificate
is registered at the close of business on the Record Date, in an amount equal to
the product of the Percentage Interest evidenced by this Certificate and the
Group I-A Distribution Amount for the Class I-A-14 Certificates required to be
distributed to Holders of the Class I-A-14 Certificates on such Distribution
Date, subject to adjustment in certain events as specified in the Agreement.
Distributions in reduction of the Principal Balance of certain Classes of Class
A Certificates may not commence on the first Distribution Date specified above.
Distributions of principal will be allocated among the Classes of Group I-A
Certificates in accordance with the provisions of the Agreement. The
pass-through rate on the Class I-A-14 Certificates applicable to each
Distribution Date will be 5.750% per annum. The amount of interest which accrues
on this Certificate in any month will be subject to reduction with respect to
any Non-Supported Interest Shortfall, any Relief Act Shortfall and the interest
portion of certain Realized Losses allocated to the Class I-A-14 Certificates,
as described in the Agreement.

      Distributions on this Certificate will be made by the Paying Agent by
check mailed to the address of the Person entitled thereto, as such name and
address shall appear on the Certificate Register, unless such Person is entitled
to receive payments by wire transfer in immediately available funds in
accordance with the Agreement and such Person has notified the Paying Agent
pursuant to the Agreement that such payments are to be made by wire transfer of
immediately available funds. Notwithstanding the above, the final distribution
in reduction of the Principal Balance of this Certificate will be made after due
notice of the pendency of such distribution and only upon presentation and
surrender of this Certificate at the office or agency of the Paying Agent
specified for that purpose in the notice of final distribution.

      Reference is hereby made to the further provisions of this Certificate set
forth on the reverse hereof, which further provisions shall for all purposes
have the same effect as if set forth at this place.

      This Certificate constitutes a "regular interest" in a "real estate
mortgage investment conduit" as those terms are defined in Section 860G(a)(1)
and Section 860D, respectively, of the Internal Revenue Code of 1986, as
amended.

      Unless this Certificate has been countersigned by an authorized officer of
the Authenticating Agent, by manual signature, this Certificate shall not be
entitled to any benefit under the Agreement or be valid for any purpose.


<PAGE>

      IN WITNESS WHEREOF, the Paying Agent has caused this Certificate to be
duly executed as of the date set forth below.

Dated:

                                       Wells Fargo Bank, N.A.,
                                            Paying Agent

                                       By____________________________
                                            Authorized Officer

Countersigned:

Wells Fargo Bank, N.A.,
  Authenticating Agent

By ________________________
   Authorized Officer


<PAGE>

                               EXHIBIT A-I-A-R
                  [FORM OF FACE OF CLASS I-A-R CERTIFICATE]

FOR U.S. FEDERAL INCOME TAX PURPOSES, THIS CERTIFICATE REPRESENTS THE "RESIDUAL
INTERESTS" IN TWO "REAL ESTATE MORTGAGE INVESTMENT CONDUITS" AS THOSE TERMS ARE
DEFINED, RESPECTIVELY, IN SECTIONS 860G(a)(2) AND 860D OF THE INTERNAL REVENUE
CODE OF 1986, AS AMENDED (THE "CODE"). A TRANSFEREE OF THIS CERTIFICATE, BY
ACCEPTANCE HEREOF, IS DEEMED TO HAVE ACCEPTED THIS CERTIFICATE SUBJECT TO
CERTAIN RESTRICTIONS ON TRANSFERABILITY, AS SET FORTH IN SECTION 5.02(d) OF THE
AGREEMENT, AND SHALL BE REQUIRED TO FURNISH AN AFFIDAVIT TO THE TRANSFEROR AND
THE TRUSTEE TO THE EFFECT THAT, AMONG OTHER THINGS, IT IS NOT A DISQUALIFIED
ORGANIZATION, AS SUCH TERM IS DEFINED IN CODE SECTION 860E(e)(5), AN AGENT
(INCLUDING A BROKER, NOMINEE OR OTHER MIDDLEMAN) FOR A DISQUALIFIED ORGANIZATION
OR A NON-PERMITTED FOREIGN HOLDER, AS DEFINED IN SECTION 5.02(d) OF THE
AGREEMENT AND TO HAVE AGREED TO SUCH AMENDMENTS TO THE AGREEMENT AS MAY BE
REQUIRED TO FURTHER EFFECTUATE THE RESTRICTIONS ON TRANSFERS TO DISQUALIFIED
ORGANIZATIONS, AGENTS THEREOF OR NON-PERMITTED FOREIGN HOLDERS.

THE HOLDER OF THIS CLASS I-A-R CERTIFICATE, BY ACCEPTANCE HEREOF, IS DEEMED TO
HAVE AGREED TO THE DESIGNATION OF THE MASTER SERVICER AS ITS AGENT TO ACT AS
"TAX MATTERS PERSON" OF THE UPPER-TIER REMIC AND LOWER-TIER REMIC TO PERFORM THE
FUNCTIONS OF A "TAX MATTERS PARTNER" FOR PURPOSES OF SUBCHAPTER C OF CHAPTER 63
OF SUBTITLE F OF THE CODE, OR, IF SO REQUESTED BY THE MASTER SERVICER, TO ACT AS
TAX MATTERS PERSON OF THE UPPER-TIER REMIC AND LOWER-TIER REMIC.

THIS CERTIFICATE MAY NOT BE PURCHASED BY OR TRANSFERRED TO ANY PERSON WHICH IS
AN EMPLOYEE BENEFIT PLAN OR OTHER RETIREMENT ARRANGEMENT SUBJECT TO TITLE I OF
THE EMPLOYEE RETIREMENT INCOME SECURITY ACT OF 1974, AS AMENDED ("ERISA"), OR
SECTION 4975 OF THE CODE OR A GOVERNMENTAL PLAN, AS DEFINED IN SECTION 3(32) OF
ERISA SUBJECT TO ANY FEDERAL, STATE OR LOCAL LAW WHICH IS, TO A MATERIAL EXTENT,
SIMILAR TO THE FOREGOING PROVISIONS OF ERISA OR THE CODE (COLLECTIVELY, A
"PLAN"), OR ANY PERSON ACTING ON BEHALF OF OR INVESTING THE ASSETS OF A PLAN.


                        MORTGAGE PASS-THROUGH CERTIFICATE
                           SERIES 2006-4, CLASS I-A-R

                    evidencing an interest in a pool of fixed
                           interest rate, monthly pay,
                      fully amortizing, first lien, one- to
                 four-family residential mortgage loans sold by

                    WELLS FARGO ASSET SECURITIES CORPORATION
               (Not an interest in or obligation of the Depositor)

            THIS CERTIFICATE DOES NOT EVIDENCE AN OBLIGATION OF, OR AN INTEREST
IN, THE DEPOSITOR, THE MASTER SERVICER, THE TRUSTEE OR ANY OF THEIR AFFILIATES,
AND IS NOT INSURED OR GUARANTEED BY THE DEPOSITOR, THE MASTER SERVICER, THE
TRUSTEE OR ANY OF THEIR AFFILIATES, OR BY ANY GOVERNMENT AGENCY OR PRIVATE
INSURER.

            DISTRIBUTIONS IN REDUCTION OF THE PRINCIPAL BALANCE OF THIS
CERTIFICATE WILL BE MADE IN THE MANNER DESCRIBED IN THE AGREEMENT. ACCORDINGLY,
THE OUTSTANDING PRINCIPAL BALANCE OF THIS CERTIFICATE AT ANY TIME MAY BE LESS
THAN THE INITIAL PRINCIPAL BALANCE REPRESENTED HEREBY.

Certificate No.                  Cut-Off Date:  March 1, 2006

CUSIP No.: 94983B AQ 2           First Distribution Date:  April 25, 2006

ISIN No.: US94983BAQ23           Denomination: $

Percentage Interest evidenced
by this Certificate:  %          Final Scheduled Maturity Date:  April 25, 2036


      THIS CERTIFIES THAT __________________________ is the registered owner of
the Percentage Interest evidenced by this Certificate in monthly distributions
to the Holder of the Class I-A-R Certificate with respect to a Trust Estate
consisting of a pool of fixed interest rate, monthly pay, fully amortizing,
first lien, one- to four-family residential mortgage loans, other than the Fixed
Retained Yield, if any, with respect thereto, consisting of two loan groups (the
"Group I Mortgage Loans" and "Group II Mortgage Loans," respectively), formed by
Wells Fargo Asset Securities Corporation (hereinafter called the "Depositor,"
which term includes any successor entity under the Agreement referred to below).
The Trust Estate was created pursuant to a Pooling and Servicing Agreement dated
as of March 30, 2006 (the "Agreement") among the Depositor, Wells Fargo Bank,
N.A., as master servicer (the "Master Servicer") and U.S. Bank National
Association, as trustee (the "Trustee"), a summary of certain of the pertinent
provisions of which is set forth hereinafter. To the extent not defined herein,
the capitalized terms used herein have the meanings ascribed to such terms in
the Agreement. This Certificate is issued under and is subject to the terms,
provisions and conditions of the Agreement, to which Agreement the Holder of
this Certificate by virtue of the acceptance hereof assents and by which such
Holder is bound.

      Pursuant to the terms of the Agreement, a distribution will be made on the
25th day of each month or, if such 25th day is not a Business Day, the Business
Day immediately following (the "Distribution Date"), commencing on the first
Distribution Date specified above, to the Person in whose name this Certificate
is registered at the close of business on the Record Date, in an amount equal to
the product of the Percentage Interest evidenced by this Certificate and the
Group I-A Distribution Amount for the Class I-A-R Certificate required to be
distributed to the Holder of the Class I-A-R Certificate on such Distribution
Date, subject to adjustment in certain events as specified in the Agreement.
Distributions in reduction of the Principal Balance of certain Classes of Class
A Certificates may not commence on the first Distribution Date specified above.
Distributions of principal will be allocated among the Classes of Group I-A
Certificates in accordance with the provisions of the Agreement. The
pass-through rate on the Class I-A-R Certificate applicable to each Distribution
Date will be 5.750% per annum. The amount of interest which accrues on this
Certificate in any month will be subject to reduction with respect to any
Non-Supported Interest Shortfall, any Relief Act Shortfall and the interest
portion of certain Realized Losses allocated to the Class I-A-R Certificate, as
described in the Agreement.

      Distributions on this Certificate will be made by the Paying Agent by
check mailed to the address of the Person entitled thereto, as such name and
address shall appear on the Certificate Register. Notwithstanding the above, the
final distribution on this Certificate will be made after due notice of the
pendency of such distribution and only upon presentation and surrender of this
Certificate at the office or agency of the Paying Agent specified for that
purpose in the notice of final distribution.

      Reference is hereby made to the further provisions of this Certificate set
forth on the reverse hereof, which further provisions shall for all purposes
have the same effect as if set forth at this place.

      Unless this Certificate has been countersigned by an authorized officer of
the Authenticating Agent, by manual signature, this Certificate shall not be
entitled to any benefit under the Agreement or be valid for any purpose.


<PAGE>

      IN WITNESS WHEREOF, the Paying Agent has caused this Certificate to be
duly executed as of the date set forth below.

Dated:

                                       Wells Fargo Bank, N.A.,
                                            Paying Agent

                                       By____________________________
                                            Authorized Officer

Countersigned:

Wells Fargo Bank, N.A.,
  Authenticating Agent

By ________________________
      Authorized Officer


<PAGE>

                                EXHIBIT A-I-A-PO
                   [FORM OF FACE OF CLASS I-A-PO CERTIFICATE]

  [UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE
   DEPOSITORY TRUST COMPANY TO THE DEPOSITOR OR ITS AGENT FOR REGISTRATION OF
 TRANSFER, EXCHANGE OR PAYMENT, AND ANY CERTIFICATE ISSUED IS REGISTERED IN THE
       NAME OF CEDE & CO. OR SUCH OTHER NAME AS REQUESTED BY AN AUTHORIZED
REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY AND ANY PAYMENT IS MADE TO CEDE &
  CO., ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO
  ANY PERSON IS WRONGFUL SINCE THE REGISTERED OWNER HEREOF, CEDE & CO., HAS AN
                                INTEREST HEREIN.]

                        MORTGAGE PASS-THROUGH CERTIFICATE
                           SERIES 2006-4, CLASS I-A-PO

                    evidencing an interest in a pool of fixed
                           interest rate, monthly pay,
                      fully amortizing, first lien, one- to
                 four-family residential mortgage loans sold by

                    WELLS FARGO ASSET SECURITIES CORPORATION
               (Not an interest in or obligation of the Depositor)

            THIS CERTIFICATE DOES NOT EVIDENCE AN OBLIGATION OF, OR AN INTEREST
IN, THE DEPOSITOR, THE MASTER SERVICER, THE TRUSTEE OR ANY OF THEIR AFFILIATES,
AND IS NOT INSURED OR GUARANTEED BY THE DEPOSITOR, THE MASTER SERVICER, THE
TRUSTEE OR ANY OF THEIR AFFILIATES, OR BY ANY GOVERNMENT AGENCY OR PRIVATE
INSURER.

            DISTRIBUTIONS IN REDUCTION OF THE PRINCIPAL BALANCE OF THIS
CERTIFICATE WILL BE MADE IN THE MANNER DESCRIBED IN THE AGREEMENT. ACCORDINGLY,
THE OUTSTANDING PRINCIPAL BALANCE OF THIS CERTIFICATE AT ANY TIME MAY BE LESS
THAN THE INITIAL PRINCIPAL BALANCE REPRESENTED HEREBY.

Certificate No.                        Cut-Off Date:  March 1, 2006

CUSIP No.:  94983B AR 0                First Distribution Date: April 25, 2006

ISIN No.: US94983BAR06                 Denomination:  $

Percentage Interest evidenced          Final Scheduled Maturity Date:  April 25,
by this Certificate: %                 2036


      THIS CERTIFIES THAT ___________________________ is the registered owner of
the Percentage Interest evidenced by this Certificate in monthly distributions
to the Holders of the Class I-A-PO Certificates with respect to a Trust Estate
consisting of a pool of fixed interest rate, monthly pay, fully amortizing,
first lien, one- to four-family residential mortgage loans, other than the Fixed
Retained Yield, if any, with respect thereto, consisting of two loan groups (the
"Group I Mortgage Loans" and "Group II Mortgage Loans," respectively), formed by
Wells Fargo Asset Securities Corporation (hereinafter called the "Depositor,"
which term includes any successor entity under the Agreement referred to below).
The Trust Estate was created pursuant to a Pooling and Servicing Agreement dated
as of March 30, 2006 (the "Agreement") among the Depositor, Wells Fargo Bank,
N.A., as master servicer (the "Master Servicer") and U.S. Bank National
Association, as trustee (the "Trustee"), a summary of certain of the pertinent
provisions of which is set forth hereinafter. To the extent not defined herein,
the capitalized terms used herein have the meanings ascribed to such terms in
the Agreement. This Certificate is issued under and is subject to the terms,
provisions and conditions of the Agreement, to which Agreement the Holder of
this Certificate by virtue of the acceptance hereof assents and by which such
Holder is bound.

      Pursuant to the terms of the Agreement, a distribution will be made on the
25th day of each month or, if such 25th day is not a Business Day, the Business
Day immediately following (the "Distribution Date"), commencing on the first
Distribution Date specified above, to the Person in whose name this Certificate
is registered at the close of business on the Record Date, in an amount equal to
the product of the Percentage Interest evidenced by this Certificate and the
Group I-A Distribution Amount for the Class I-A-PO Certificates required to be
distributed to Holders of the Class I-A-PO Certificates on such Distribution
Date, subject to adjustment in certain events as specified in the Agreement.
Distributions in reduction of the Principal Balance of certain Classes of Class
A Certificates may not commence on the first Distribution Date specified above.
Distributions of principal will be allocated among the Classes of Group I-A
Certificates in accordance with the provisions of the Agreement. The Class
I-A-PO Certificates are principal only Certificates and are not entitled to
distributions in respect of interest.

      Distributions on this Certificate will be made by the Paying Agent by
check mailed to the address of the Person entitled thereto, as such name and
address shall appear on the Certificate Register, unless such Person is entitled
to receive payments by wire transfer in immediately available funds in
accordance with the Agreement and such Person has notified the Paying Agent
pursuant to the Agreement that such payments are to be made by wire transfer of
immediately available funds. Notwithstanding the above, the final distribution
in reduction of the Principal Balance of this Certificate will be made after due
notice of the pendency of such distribution and only upon presentation and
surrender of this Certificate at the office or agency of the Paying Agent
specified for that purpose in the notice of final distribution.

      Reference is hereby made to the further provisions of this Certificate set
forth on the reverse hereof, which further provisions shall for all purposes
have the same effect as if set forth at this place.

      This Certificate constitutes a "regular interest" in a "real estate
mortgage investment conduit" as those terms are defined in Section 860G(a)(1)
and Section 860D, respectively, of the Internal Revenue Code of 1986, as
amended.

      Unless this Certificate has been countersigned by an authorized officer of
the Authenticating Agent, by manual signature, this Certificate shall not be
entitled to any benefit under the Agreement or be valid for any purpose.


<PAGE>

      IN WITNESS WHEREOF, the Paying Agent has caused this Certificate to be
duly executed as of the date set forth below.

Dated:

                                       Wells Fargo Bank, N.A.,
                                            Paying Agent

                                       By____________________________
                                            Authorized Officer

Countersigned:

Wells Fargo Bank, N.A.,
  Authenticating Agent

By ________________________
   Authorized Officer


<PAGE>

                                EXHIBIT A-II-A-1
                   [FORM OF FACE OF CLASS II-A-1 CERTIFICATE]

  [UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE
   DEPOSITORY TRUST COMPANY TO THE DEPOSITOR OR ITS AGENT FOR REGISTRATION OF
 TRANSFER, EXCHANGE OR PAYMENT, AND ANY CERTIFICATE ISSUED IS REGISTERED IN THE
       NAME OF CEDE & CO. OR SUCH OTHER NAME AS REQUESTED BY AN AUTHORIZED
REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY AND ANY PAYMENT IS MADE TO CEDE &
  CO., ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO
  ANY PERSON IS WRONGFUL SINCE THE REGISTERED OWNER HEREOF, CEDE & CO., HAS AN
                                INTEREST HEREIN.]

                        MORTGAGE PASS-THROUGH CERTIFICATE
                           SERIES 2006-4, CLASS II-A-1

                    evidencing an interest in a pool of fixed
                           interest rate, monthly pay,
                      fully amortizing, first lien, one- to
                 four-family residential mortgage loans sold by

                    WELLS FARGO ASSET SECURITIES CORPORATION
             (Not an interest in or obligation of the Depositor)

            THIS CERTIFICATE DOES NOT EVIDENCE AN OBLIGATION OF, OR AN INTEREST
IN, THE DEPOSITOR, THE MASTER SERVICER, THE TRUSTEE OR ANY OF THEIR AFFILIATES,
AND IS NOT INSURED OR GUARANTEED BY THE DEPOSITOR, THE MASTER SERVICER, THE
TRUSTEE OR ANY OF THEIR AFFILIATES, OR BY ANY GOVERNMENT AGENCY OR PRIVATE
INSURER.

            DISTRIBUTIONS IN REDUCTION OF THE PRINCIPAL BALANCE OF THIS
CERTIFICATE WILL BE MADE IN THE MANNER DESCRIBED IN THE AGREEMENT. ACCORDINGLY,
THE OUTSTANDING PRINCIPAL BALANCE OF THIS CERTIFICATE AT ANY TIME MAY BE LESS
THAN THE INITIAL PRINCIPAL BALANCE REPRESENTED HEREBY.

Certificate No.                        Cut-Off Date:  March 1, 2006

CUSIP No.: 94983B AS 8                 First Distribution Date: April 25, 2006

ISIN No.: US94983BAS88                 Denomination:  $

Percentage Interest evidenced          Final Scheduled Maturity Date:  April 25,
by this Certificate: %                 2036


      THIS CERTIFIES THAT ___________________________ is the registered owner of
the Percentage Interest evidenced by this Certificate in monthly distributions
to the Holders of the Class II-A-1 Certificates with respect to a Trust Estate
consisting of a pool of fixed interest rate, monthly pay, fully amortizing,
first lien, one- to four-family residential mortgage loans, other than the Fixed
Retained Yield, if any, with respect thereto, consisting of two loan groups (the
"Group I Mortgage Loans" and "Group II Mortgage Loans," respectively), formed by
Wells Fargo Asset Securities Corporation (hereinafter called the "Depositor,"
which term includes any successor entity under the Agreement referred to below).
The Trust Estate was created pursuant to a Pooling and Servicing Agreement dated
as of March 30, 2006 (the "Agreement") among the Depositor, Wells Fargo Bank,
N.A., as master servicer (the "Master Servicer") and U.S. Bank National
Association, as trustee (the "Trustee"), a summary of certain of the pertinent
provisions of which is set forth hereinafter. To the extent not defined herein,
the capitalized terms used herein have the meanings ascribed to such terms in
the Agreement. This Certificate is issued under and is subject to the terms,
provisions and conditions of the Agreement, to which Agreement the Holder of
this Certificate by virtue of the acceptance hereof assents and by which such
Holder is bound.

      Pursuant to the terms of the Agreement, a distribution will be made on the
25th day of each month or, if such 25th day is not a Business Day, the Business
Day immediately following (the "Distribution Date"), commencing on the first
Distribution Date specified above, to the Person in whose name this Certificate
is registered at the close of business on the Record Date, in an amount equal to
the product of the Percentage Interest evidenced by this Certificate and the
Group II-A Distribution Amount for the Class II-A-1 Certificates required to be
distributed to Holders of the Class II-A-1 Certificates on such Distribution
Date, subject to adjustment in certain events as specified in the Agreement.
Distributions in reduction of the Principal Balance of certain Classes of Class
A Certificates may not commence on the first Distribution Date specified above.
Distributions of principal will be allocated among the Classes of Group II-A
Certificates in accordance with the provisions of the Agreement. The
pass-through rate on the Class II-A-1 Certificates applicable to each
Distribution Date will be 6.000% per annum. The amount of interest which accrues
on this Certificate in any month will be subject to reduction with respect to
any Non-Supported Interest Shortfall, any Relief Act Shortfall and the interest
portion of certain Realized Losses allocated to the Class II-A-1 Certificates,
as described in the Agreement.

      Distributions on this Certificate will be made by the Paying Agent by
check mailed to the address of the Person entitled thereto, as such name and
address shall appear on the Certificate Register, unless such Person is entitled
to receive payments by wire transfer in immediately available funds in
accordance with the Agreement and such Person has notified the Paying Agent
pursuant to the Agreement that such payments are to be made by wire transfer of
immediately available funds. Notwithstanding the above, the final distribution
in reduction of the Principal Balance of this Certificate will be made after due
notice of the pendency of such distribution and only upon presentation and
surrender of this Certificate at the office or agency of the Paying Agent
specified for that purpose in the notice of final distribution.

      Reference is hereby made to the further provisions of this Certificate set
forth on the reverse hereof, which further provisions shall for all purposes
have the same effect as if set forth at this place.

      This Certificate constitutes a "regular interest" in a "real estate
mortgage investment conduit" as those terms are defined in Section 860G(a)(1)
and Section 860D, respectively, of the Internal Revenue Code of 1986, as
amended.

      Unless this Certificate has been countersigned by an authorized officer of
the Authenticating Agent, by manual signature, this Certificate shall not be
entitled to any benefit under the Agreement or be valid for any purpose.


<PAGE>

            IN WITNESS WHEREOF, the Paying Agent has caused this Certificate to
be duly executed as of the date set forth below.

Dated:

                                       Wells Fargo Bank, N.A.,
                                            Paying Agent

                                       By____________________________
                                            Authorized Officer

Countersigned:

Wells Fargo Bank, N.A.,
  Authenticating Agent

By ________________________
   Authorized Officer


<PAGE>

                                EXHIBIT A-II-A-2
                   [FORM OF FACE OF CLASS II-A-2 CERTIFICATE]

  [UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE
   DEPOSITORY TRUST COMPANY TO THE DEPOSITOR OR ITS AGENT FOR REGISTRATION OF
 TRANSFER, EXCHANGE OR PAYMENT, AND ANY CERTIFICATE ISSUED IS REGISTERED IN THE
       NAME OF CEDE & CO. OR SUCH OTHER NAME AS REQUESTED BY AN AUTHORIZED
REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY AND ANY PAYMENT IS MADE TO CEDE &
  CO., ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO
  ANY PERSON IS WRONGFUL SINCE THE REGISTERED OWNER HEREOF, CEDE & CO., HAS AN
                                INTEREST HEREIN.]

                        MORTGAGE PASS-THROUGH CERTIFICATE
                           SERIES 2006-4, CLASS II-A-2

                    evidencing an interest in a pool of fixed
                           interest rate, monthly pay,
                      fully amortizing, first lien, one- to
                 four-family residential mortgage loans sold by

                    WELLS FARGO ASSET SECURITIES CORPORATION
               (Not an interest in or obligation of the Depositor)

            THIS CERTIFICATE DOES NOT EVIDENCE AN OBLIGATION OF, OR AN INTEREST
IN, THE DEPOSITOR, THE MASTER SERVICER, THE TRUSTEE OR ANY OF THEIR AFFILIATES,
AND IS NOT INSURED OR GUARANTEED BY THE DEPOSITOR, THE MASTER SERVICER, THE
TRUSTEE OR ANY OF THEIR AFFILIATES, OR BY ANY GOVERNMENT AGENCY OR PRIVATE
INSURER.

            DISTRIBUTIONS IN REDUCTION OF THE PRINCIPAL BALANCE OF THIS
CERTIFICATE WILL BE MADE IN THE MANNER DESCRIBED IN THE AGREEMENT. ACCORDINGLY,
THE OUTSTANDING PRINCIPAL BALANCE OF THIS CERTIFICATE AT ANY TIME MAY BE LESS
THAN THE INITIAL PRINCIPAL BALANCE REPRESENTED HEREBY.

Certificate No.                        Cut-Off Date:  March 1, 2006

CUSIP No.: 94983B AT 6                 First Distribution Date: April 25, 2006

ISIN No.: US94983BAT61                 Denomination:  $

Percentage Interest evidenced          Final Scheduled Maturity Date:  April 25,
by this Certificate: %                 2036


      THIS CERTIFIES THAT ___________________________ is the registered owner of
the Percentage Interest evidenced by this Certificate in monthly distributions
to the Holders of the Class II-A-2 Certificates with respect to a Trust Estate
consisting of a pool of fixed interest rate, monthly pay, fully amortizing,
first lien, one- to four-family residential mortgage loans, other than the Fixed
Retained Yield, if any, with respect thereto, consisting of two loan groups (the
"Group I Mortgage Loans" and "Group II Mortgage Loans," respectively), formed by
Wells Fargo Asset Securities Corporation (hereinafter called the "Depositor,"
which term includes any successor entity under the Agreement referred to below).
The Trust Estate was created pursuant to a Pooling and Servicing Agreement dated
as of March 30, 2006 (the "Agreement") among the Depositor, Wells Fargo Bank,
N.A., as master servicer (the "Master Servicer") and U.S. Bank National
Association, as trustee (the "Trustee"), a summary of certain of the pertinent
provisions of which is set forth hereinafter. To the extent not defined herein,
the capitalized terms used herein have the meanings ascribed to such terms in
the Agreement. This Certificate is issued under and is subject to the terms,
provisions and conditions of the Agreement, to which Agreement the Holder of
this Certificate by virtue of the acceptance hereof assents and by which such
Holder is bound.

      Pursuant to the terms of the Agreement, a distribution will be made on the
25th day of each month or, if such 25th day is not a Business Day, the Business
Day immediately following (the "Distribution Date"), commencing on the first
Distribution Date specified above, to the Person in whose name this Certificate
is registered at the close of business on the Record Date, in an amount equal to
the product of the Percentage Interest evidenced by this Certificate and the
Group II-A Distribution Amount for the Class II-A-2 Certificates required to be
distributed to Holders of the Class II-A-2 Certificates on such Distribution
Date, subject to adjustment in certain events as specified in the Agreement.
Distributions in reduction of the Principal Balance of certain Classes of Class
A Certificates may not commence on the first Distribution Date specified above.
Distributions of principal will be allocated among the Classes of Group II-A
Certificates in accordance with the provisions of the Agreement. The
pass-through rate on the Class II-A-2 Certificates applicable to each
Distribution Date will be 5.500% per annum. The amount of interest which accrues
on this Certificate in any month will be subject to reduction with respect to
any Non-Supported Interest Shortfall, any Relief Act Shortfall and the interest
portion of certain Realized Losses allocated to the Class II-A-2 Certificates,
as described in the Agreement.

      Distributions on this Certificate will be made by the Paying Agent by
check mailed to the address of the Person entitled thereto, as such name and
address shall appear on the Certificate Register, unless such Person is entitled
to receive payments by wire transfer in immediately available funds in
accordance with the Agreement and such Person has notified the Paying Agent
pursuant to the Agreement that such payments are to be made by wire transfer of
immediately available funds. Notwithstanding the above, the final distribution
in reduction of the Principal Balance of this Certificate will be made after due
notice of the pendency of such distribution and only upon presentation and
surrender of this Certificate at the office or agency of the Paying Agent
specified for that purpose in the notice of final distribution.

      Reference is hereby made to the further provisions of this Certificate set
forth on the reverse hereof, which further provisions shall for all purposes
have the same effect as if set forth at this place.

      This Certificate constitutes a "regular interest" in a "real estate
mortgage investment conduit" as those terms are defined in Section 860G(a)(1)
and Section 860D, respectively, of the Internal Revenue Code of 1986, as
amended.

      Unless this Certificate has been countersigned by an authorized officer of
the Authenticating Agent, by manual signature, this Certificate shall not be
entitled to any benefit under the Agreement or be valid for any purpose.


<PAGE>

            IN WITNESS WHEREOF, the Paying Agent has caused this Certificate to
be duly executed as of the date set forth below.

Dated:

                                       Wells Fargo Bank, N.A.,
                                            Paying Agent

                                       By____________________________
                                            Authorized Officer

Countersigned:

Wells Fargo Bank, N.A.,
  Authenticating Agent

By ________________________
   Authorized Officer


<PAGE>

                                EXHIBIT A-II-A-3
                   [FORM OF FACE OF CLASS II-A-3 CERTIFICATE]

  [UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE
   DEPOSITORY TRUST COMPANY TO THE DEPOSITOR OR ITS AGENT FOR REGISTRATION OF
 TRANSFER, EXCHANGE OR PAYMENT, AND ANY CERTIFICATE ISSUED IS REGISTERED IN THE
       NAME OF CEDE & CO. OR SUCH OTHER NAME AS REQUESTED BY AN AUTHORIZED
REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY AND ANY PAYMENT IS MADE TO CEDE &
  CO., ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO
  ANY PERSON IS WRONGFUL SINCE THE REGISTERED OWNER HEREOF, CEDE & CO., HAS AN
                                INTEREST HEREIN.]

                        MORTGAGE PASS-THROUGH CERTIFICATE
                           SERIES 2006-4, CLASS II-A-3

                    evidencing an interest in a pool of fixed
                           interest rate, monthly pay,
                      fully amortizing, first lien, one- to
                 four-family residential mortgage loans sold by

                    WELLS FARGO ASSET SECURITIES CORPORATION
               (Not an interest in or obligation of the Depositor)

            AFTER THE APPLICABLE SUBORDINATION DEPLETION DATE, THE PRINCIPAL
PORTION OF REALIZED LOSSES ALLOCATED TO THE CLASS II-A-1 AND CLASS II-A-2
CERTIFICATES WILL BE BORNE BY THE CLASS II-A-3 CERTIFICATES AS DESCRIBED IN THE
AGREEMENT.

            THIS CERTIFICATE DOES NOT EVIDENCE AN OBLIGATION OF, OR AN INTEREST
IN, THE DEPOSITOR, THE MASTER SERVICER, THE TRUSTEE OR ANY OF THEIR AFFILIATES,
AND IS NOT INSURED OR GUARANTEED BY THE DEPOSITOR, THE MASTER SERVICER, THE
TRUSTEE OR ANY OF THEIR AFFILIATES, OR BY ANY GOVERNMENT AGENCY OR PRIVATE
INSURER.

            DISTRIBUTIONS IN REDUCTION OF THE PRINCIPAL BALANCE OF THIS
CERTIFICATE WILL BE MADE IN THE MANNER DESCRIBED IN THE AGREEMENT. ACCORDINGLY,
THE OUTSTANDING PRINCIPAL BALANCE OF THIS CERTIFICATE AT ANY TIME MAY BE LESS
THAN THE INITIAL PRINCIPAL BALANCE REPRESENTED HEREBY.

Certificate No.                        Cut-Off Date:  March 1, 2006

CUSIP No.: 94983B AU 3                 First Distribution Date: April 25, 2006

ISIN No.: US94983BAU35                 Denomination:  $

Percentage Interest evidenced          Final Scheduled Maturity Date:  April 25,
by this Certificate: %                 2036


      THIS CERTIFIES THAT ___________________________ is the registered owner of
the Percentage Interest evidenced by this Certificate in monthly distributions
to the Holders of the Class II-A-3 Certificates with respect to a Trust Estate
consisting of a pool of fixed interest rate, monthly pay, fully amortizing,
first lien, one- to four-family residential mortgage loans, other than the Fixed
Retained Yield, if any, with respect thereto, consisting of two loan groups (the
"Group I Mortgage Loans" and "Group II Mortgage Loans," respectively), formed by
Wells Fargo Asset Securities Corporation (hereinafter called the "Depositor,"
which term includes any successor entity under the Agreement referred to below).
The Trust Estate was created pursuant to a Pooling and Servicing Agreement dated
as of March 30, 2006 (the "Agreement") among the Depositor, Wells Fargo Bank,
N.A., as master servicer (the "Master Servicer") and U.S. Bank National
Association, as trustee (the "Trustee"), a summary of certain of the pertinent
provisions of which is set forth hereinafter. To the extent not defined herein,
the capitalized terms used herein have the meanings ascribed to such terms in
the Agreement. This Certificate is issued under and is subject to the terms,
provisions and conditions of the Agreement, to which Agreement the Holder of
this Certificate by virtue of the acceptance hereof assents and by which such
Holder is bound.

      Pursuant to the terms of the Agreement, a distribution will be made on the
25th day of each month or, if such 25th day is not a Business Day, the Business
Day immediately following (the "Distribution Date"), commencing on the first
Distribution Date specified above, to the Person in whose name this Certificate
is registered at the close of business on the Record Date, in an amount equal to
the product of the Percentage Interest evidenced by this Certificate and the
Group II-A Distribution Amount for the Class II-A-3 Certificates required to be
distributed to Holders of the Class II-A-3 Certificates on such Distribution
Date, subject to adjustment in certain events as specified in the Agreement.
Distributions in reduction of the Principal Balance of certain Classes of Class
A Certificates may not commence on the first Distribution Date specified above.
Distributions of principal will be allocated among the Classes of Group II-A
Certificates in accordance with the provisions of the Agreement. The
pass-through rate on the Class II-A-3 Certificates applicable to each
Distribution Date will be 5.750% per annum. The amount of interest which accrues
on this Certificate in any month will be subject to reduction with respect to
any Non-Supported Interest Shortfall, any Relief Act Shortfall and the interest
portion of certain Realized Losses allocated to the Class II-A-3 Certificates,
as described in the Agreement.

      Distributions on this Certificate will be made by the Paying Agent by
check mailed to the address of the Person entitled thereto, as such name and
address shall appear on the Certificate Register, unless such Person is entitled
to receive payments by wire transfer in immediately available funds in
accordance with the Agreement and such Person has notified the Paying Agent
pursuant to the Agreement that such payments are to be made by wire transfer of
immediately available funds. Notwithstanding the above, the final distribution
in reduction of the Principal Balance of this Certificate will be made after due
notice of the pendency of such distribution and only upon presentation and
surrender of this Certificate at the office or agency of the Paying Agent
specified for that purpose in the notice of final distribution.

      Reference is hereby made to the further provisions of this Certificate set
forth on the reverse hereof, which further provisions shall for all purposes
have the same effect as if set forth at this place.

      This Certificate constitutes a "regular interest" in a "real estate
mortgage investment conduit" as those terms are defined in Section 860G(a)(1)
and Section 860D, respectively, of the Internal Revenue Code of 1986, as
amended.

      Unless this Certificate has been countersigned by an authorized officer of
the Authenticating Agent, by manual signature, this Certificate shall not be
entitled to any benefit under the Agreement or be valid for any purpose.


<PAGE>

            IN WITNESS WHEREOF, the Paying Agent has caused this Certificate to
be duly executed as of the date set forth below.

Dated:

                                       Wells Fargo Bank, N.A.,
                                            Paying Agent

                                       By____________________________
                                            Authorized Officer

Countersigned:

Wells Fargo Bank, N.A.,
  Authenticating Agent

By ________________________
   Authorized Officer


<PAGE>

                                EXHIBIT A-II-A-PO
                   [FORM OF FACE OF CLASS II-A-PO CERTIFICATE]

  [UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE
   DEPOSITORY TRUST COMPANY TO THE DEPOSITOR OR ITS AGENT FOR REGISTRATION OF
 TRANSFER, EXCHANGE OR PAYMENT, AND ANY CERTIFICATE ISSUED IS REGISTERED IN THE
       NAME OF CEDE & CO. OR SUCH OTHER NAME AS REQUESTED BY AN AUTHORIZED
REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY AND ANY PAYMENT IS MADE TO CEDE &
  CO., ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO
  ANY PERSON IS WRONGFUL SINCE THE REGISTERED OWNER HEREOF, CEDE & CO., HAS AN
                                INTEREST HEREIN.]

                        MORTGAGE PASS-THROUGH CERTIFICATE
                          SERIES 2006-4, CLASS II-A-PO

                    evidencing an interest in a pool of fixed
                           interest rate, monthly pay,
                      fully amortizing, first lien, one- to
                 four-family residential mortgage loans sold by

                    WELLS FARGO ASSET SECURITIES CORPORATION
               (Not an interest in or obligation of the Depositor)

            THIS CERTIFICATE DOES NOT EVIDENCE AN OBLIGATION OF, OR AN INTEREST
IN, THE DEPOSITOR, THE MASTER SERVICER, THE TRUSTEE OR ANY OF THEIR AFFILIATES,
AND IS NOT INSURED OR GUARANTEED BY THE DEPOSITOR, THE MASTER SERVICER, THE
TRUSTEE OR ANY OF THEIR AFFILIATES, OR BY ANY GOVERNMENT AGENCY OR PRIVATE
INSURER.

            DISTRIBUTIONS IN REDUCTION OF THE PRINCIPAL BALANCE OF THIS
CERTIFICATE WILL BE MADE IN THE MANNER DESCRIBED IN THE AGREEMENT. ACCORDINGLY,
THE OUTSTANDING PRINCIPAL BALANCE OF THIS CERTIFICATE AT ANY TIME MAY BE LESS
THAN THE INITIAL PRINCIPAL BALANCE REPRESENTED HEREBY.

Certificate No.                        Cut-Off Date:  March 1, 2006

CUSIP No.:  94983B AV 1                First Distribution Date: April 25, 2006

ISIN No.: US94983BAV18                 Denomination:  $

Percentage Interest evidenced          Final Scheduled Maturity Date:  April 25,
by this Certificate: %                 2036


      THIS CERTIFIES THAT ___________________________ is the registered owner of
the Percentage Interest evidenced by this Certificate in monthly distributions
to the Holders of the Class II-A-PO Certificates with respect to a Trust Estate
consisting of a pool of fixed interest rate, monthly pay, fully amortizing,
first lien, one- to four-family residential mortgage loans, other than the Fixed
Retained Yield, if any, with respect thereto, consisting of two loan groups (the
"Group I Mortgage Loans" and "Group II Mortgage Loans," respectively), formed by
Wells Fargo Asset Securities Corporation (hereinafter called the "Depositor,"
which term includes any successor entity under the Agreement referred to below).
The Trust Estate was created pursuant to a Pooling and Servicing Agreement dated
as of March 30, 2006 (the "Agreement") among the Depositor, Wells Fargo Bank,
N.A., as master servicer (the "Master Servicer") and U.S. Bank National
Association, as trustee (the "Trustee"), a summary of certain of the pertinent
provisions of which is set forth hereinafter. To the extent not defined herein,
the capitalized terms used herein have the meanings ascribed to such terms in
the Agreement. This Certificate is issued under and is subject to the terms,
provisions and conditions of the Agreement, to which Agreement the Holder of
this Certificate by virtue of the acceptance hereof assents and by which such
Holder is bound.

      Pursuant to the terms of the Agreement, a distribution will be made on the
25th day of each month or, if such 25th day is not a Business Day, the Business
Day immediately following (the "Distribution Date"), commencing on the first
Distribution Date specified above, to the Person in whose name this Certificate
is registered at the close of business on the Record Date, in an amount equal to
the product of the Percentage Interest evidenced by this Certificate and the
Group II-A Distribution Amount for the Class II-A-PO Certificates required to be
distributed to Holders of the Class II-A-PO Certificates on such Distribution
Date, subject to adjustment in certain events as specified in the Agreement.
Distributions in reduction of the Principal Balance of certain Classes of Class
A Certificates may not commence on the first Distribution Date specified above.
Distributions of principal will be allocated among the Classes of Group II-A
Certificates in accordance with the provisions of the Agreement. The Class
II-A-PO Certificates are principal only Certificates and are not entitled to
distributions in respect of interest.

      Distributions on this Certificate will be made by the Paying Agent by
check mailed to the address of the Person entitled thereto, as such name and
address shall appear on the Certificate Register, unless such Person is entitled
to receive payments by wire transfer in immediately available funds in
accordance with the Agreement and such Person has notified the Paying Agent
pursuant to the Agreement that such payments are to be made by wire transfer of
immediately available funds. Notwithstanding the above, the final distribution
in reduction of the Principal Balance of this Certificate will be made after due
notice of the pendency of such distribution and only upon presentation and
surrender of this Certificate at the office or agency of the Paying Agent
specified for that purpose in the notice of final distribution.

      Reference is hereby made to the further provisions of this Certificate set
forth on the reverse hereof, which further provisions shall for all purposes
have the same effect as if set forth at this place.

      This Certificate constitutes a "regular interest" in a "real estate
mortgage investment conduit" as those terms are defined in Section 860G(a)(1)
and Section 860D, respectively, of the Internal Revenue Code of 1986, as
amended.

      Unless this Certificate has been countersigned by an authorized officer of
the Authenticating Agent, by manual signature, this Certificate shall not be
entitled to any benefit under the Agreement or be valid for any purpose.


<PAGE>

            IN WITNESS WHEREOF, the Paying Agent has caused this Certificate to
be duly executed as of the date set forth below.

Dated:

                                       Wells Fargo Bank, N.A.,
                                            Paying Agent

                                       By____________________________
                                            Authorized Officer

Countersigned:

Wells Fargo Bank, N.A.,
  Authenticating Agent

By ________________________
   Authorized Officer


<PAGE>

                                  EXHIBIT I-B-1
                    [FORM OF FACE OF CLASS I-B-1 CERTIFICATE]

THIS CERTIFICATE IS SUBORDINATED IN RIGHT OF PAYMENT TO THE GROUP I-A
CERTIFICATES AS DESCRIBED IN THE AGREEMENT REFERRED TO HEREIN.

[UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE
DEPOSITORY TRUST COMPANY TO THE DEPOSITOR OR ITS AGENT FOR REGISTRATION OF
TRANSFER, EXCHANGE OR PAYMENT, AND ANY CERTIFICATE ISSUED IS REGISTERED IN THE
NAME OF CEDE & CO. OR SUCH OTHER NAME AS REQUESTED BY AN AUTHORIZED
REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY AND ANY PAYMENT IS MADE TO CEDE &
CO., ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO
ANY PERSON IS WRONGFUL SINCE THE REGISTERED OWNER HEREOF, CEDE & CO., HAS AN
INTEREST HEREIN.]

                        MORTGAGE PASS-THROUGH CERTIFICATE
                           SERIES 2006-4, CLASS I-B-1

 evidencing an interest in a pool of fixed interest rate, monthly pay, fully
amortizing, first lien, one- to four-family residential mortgage loans sold by

                    WELLS FARGO ASSET SECURITIES CORPORATION
               (Not an interest in or obligation of the Depositor)

            THIS CERTIFICATE DOES NOT EVIDENCE AN OBLIGATION OF, OR AN INTEREST
IN, THE DEPOSITOR, THE MASTER SERVICER, THE TRUSTEE OR ANY OF THEIR AFFILIATES,
AND IS NOT INSURED OR GUARANTEED BY THE DEPOSITOR, THE MASTER SERVICER, THE
TRUSTEE OR ANY OF THEIR AFFILIATES, OR BY ANY GOVERNMENT AGENCY OR PRIVATE
INSURER.

            DISTRIBUTIONS IN REDUCTION OF THE PRINCIPAL BALANCE OF THIS
CERTIFICATE WILL BE MADE IN THE MANNER DESCRIBED IN THE AGREEMENT. ACCORDINGLY,
THE OUTSTANDING PRINCIPAL BALANCE OF THIS CERTIFICATE AT ANY TIME MAY BE LESS
THAN THE INITIAL PRINCIPAL BALANCE REPRESENTED HEREBY.

Certificate No.                        Cut-Off Date:  March 1, 2006

CUSIP No.: 94983B AW 9                 First Distribution Date: April 25, 2006

ISIN No.: US94983BAW90                 Denomination:  $

Percentage Interest evidenced          Final Scheduled Maturity Date:  April 25,
by this Certificate: %                 2036


      THIS CERTIFIES THAT ____________________________ is the registered owner
of the Percentage Interest evidenced by this Certificate in monthly
distributions to the Holders of the Class I-B-1 Certificates with respect to a
Trust Estate consisting of a pool of fixed interest rate, monthly pay, fully
amortizing, first lien, one- to four-family residential mortgage loans, other
than the Fixed Retained Yield, if any, with respect thereto, consisting of two
loan groups (the "Group I Mortgage Loans" and "Group II Mortgage Loans,"
respectively), formed by Wells Fargo Asset Securities Corporation (hereinafter
called the "Depositor," which term includes any successor entity under the
Agreement referred to below). The Trust Estate was created pursuant to a Pooling
and Servicing Agreement dated as of March 30, 2006 (the "Agreement") among the
Depositor, Wells Fargo Bank, N.A., as master servicer (the "Master Servicer")
and U.S. Bank National Association, as trustee (the "Trustee"), a summary of
certain of the pertinent provisions of which is set forth hereinafter. To the
extent not defined herein, the capitalized terms used herein have the meanings
ascribed to such terms in the Agreement. This Certificate is issued under and is
subject to the terms, provisions and conditions of the Agreement, to which
Agreement the Holder of this Certificate by virtue of the acceptance hereof
assents and by which such Holder is bound.

      Pursuant to the terms of the Agreement, a distribution will be made on the
25th day of each month or, if such 25th day is not a Business Day, the Business
Day immediately following (the "Distribution Date"), commencing on the first
Distribution Date specified above, to the Person in whose name this Certificate
is registered at the close of business on the Record Date, in an amount equal to
the product of the Percentage Interest evidenced by this Certificate and,
subject to the prior rights of the Group I-A Certificates as specified in the
Agreement, any Class I-B-1 Distribution Amount required to be distributed to
Holders of the Class I-B-1 Certificates on such Distribution Date, subject to
adjustment, in certain events, as specified in the Agreement. The pass-through
rate on the Class I-B-1 Certificates applicable to each Distribution Date will
be 5.750% per annum. The amount of interest which accrues on this Certificate in
any month will be subject to reduction with respect to any Non-Supported
Interest Shortfall and any Relief Act Shortfall allocated to the Class I-B-1
Certificates, as described in the Agreement.

      Distributions on this Certificate will be made by the Paying Agent by
check mailed to the address of the Person entitled thereto, as such name and
address shall appear on the Certificate Register, unless such Person is entitled
to receive payments by wire transfer in immediately available funds in
accordance with the Agreement and such Person has notified the Paying Agent
pursuant to the Agreement that such payments are to be made by wire transfer of
immediately available funds. Notwithstanding the above, the final distribution
in reduction of the Principal Balance of this Certificate will be made after due
notice of the pendency of such distribution and only upon presentation and
surrender of this Certificate at the office or agency of the Paying Agent
specified for that purpose in the notice of final distribution.

      Reference is hereby made to the further provisions of this Certificate set
forth on the reverse hereof, which further provisions shall for all purposes
have the same effect as if set forth at this place.

      This Certificate constitutes a "regular interest" in a "real estate
mortgage investment conduit" as those terms are defined in Section 860G(a)(1)
and Section 860D, respectively, of the Internal Revenue Code of 1986, as
amended.

      Unless this Certificate has been countersigned by an authorized officer of
the Authenticating Agent, by manual signature, this Certificate shall not be
entitled to any benefit under the Agreement or be valid for any purpose.


<PAGE>

            IN WITNESS WHEREOF, the Paying Agent has caused this Certificate to
be duly executed as of the date set forth below.

Dated:

                                       Wells Fargo Bank, N.A.,
                                            Paying Agent

                                       By____________________________
                                            Authorized Officer

Countersigned:

Wells Fargo Bank, N.A.,
  Authenticating Agent

By ________________________
   Authorized Officer


<PAGE>

                                EXHIBIT I-B-2
                  [FORM OF FACE OF CLASS I-B-2 CERTIFICATE]

THIS CERTIFICATE IS SUBORDINATED IN RIGHT OF PAYMENT TO THE GROUP I-A
CERTIFICATES AND THE CLASS I-B-1 CERTIFICATES AS DESCRIBED IN THE AGREEMENT
REFERRED TO HEREIN.

[UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE
DEPOSITORY TRUST COMPANY TO THE DEPOSITOR OR ITS AGENT FOR REGISTRATION OF
TRANSFER, EXCHANGE OR PAYMENT, AND ANY CERTIFICATE ISSUED IS REGISTERED IN THE
NAME OF CEDE & CO. OR SUCH OTHER NAME AS REQUESTED BY AN AUTHORIZED
REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY AND ANY PAYMENT IS MADE TO CEDE &
CO., ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO
ANY PERSON IS WRONGFUL SINCE THE REGISTERED OWNER HEREOF, CEDE & CO., HAS AN
INTEREST HEREIN.]

                        MORTGAGE PASS-THROUGH CERTIFICATE
                           SERIES 2006-4, CLASS I-B-2

 evidencing an interest in a pool of fixed interest rate, monthly pay, fully
amortizing, first lien, one- to four-family residential mortgage loans sold by

                   WELLS FARGO ASSET SECURITIES CORPORATION
             (Not an interest in or obligation of the Depositor)

            THIS CERTIFICATE DOES NOT EVIDENCE AN OBLIGATION OF, OR AN INTEREST
IN, THE DEPOSITOR, THE MASTER SERVICER, THE TRUSTEE OR ANY OF THEIR AFFILIATES,
AND IS NOT INSURED OR GUARANTEED BY THE DEPOSITOR, THE MASTER SERVICER, THE
TRUSTEE OR ANY OF THEIR AFFILIATES, OR BY ANY GOVERNMENT AGENCY OR PRIVATE
INSURER.

            DISTRIBUTIONS IN REDUCTION OF THE PRINCIPAL BALANCE OF THIS
CERTIFICATE WILL BE MADE IN THE MANNER DESCRIBED IN THE AGREEMENT. ACCORDINGLY,
THE OUTSTANDING PRINCIPAL BALANCE OF THIS CERTIFICATE AT ANY TIME MAY BE LESS
THAN THE INITIAL PRINCIPAL BALANCE REPRESENTED HEREBY.

Certificate No.                        Cut-Off Date:  March 1, 2006

CUSIP No.:  94983B AX 7                First Distribution Date: April 25, 2006

ISIN No.: US94983BAX73                 Denomination:  $

Percentage Interest evidenced          Final Scheduled Maturity Date:  April 25,
by this Certificate: %                 2036


      THIS CERTIFIES THAT ____________________________ is the registered owner
of the Percentage Interest evidenced by this Certificate in monthly
distributions to the Holders of the Class I-B-2 Certificates with respect to a
Trust Estate consisting of a pool of fixed interest rate, monthly pay, fully
amortizing, first lien, one- to four-family residential mortgage loans, other
than the Fixed Retained Yield, if any, with respect thereto, consisting of two
loan groups (the "Group I Mortgage Loans" and "Group II Mortgage Loans,"
respectively), formed by Wells Fargo Asset Securities Corporation (hereinafter
called the "Depositor," which term includes any successor entity under the
Agreement referred to below). The Trust Estate was created pursuant to a Pooling
and Servicing Agreement dated as of March 30, 2006 (the "Agreement") among the
Depositor, Wells Fargo Bank, N.A., as master servicer (the "Master Servicer")
and U.S. Bank National Association, as trustee (the "Trustee"), a summary of
certain of the pertinent provisions of which is set forth hereinafter. To the
extent not defined herein, the capitalized terms used herein have the meanings
ascribed to such terms in the Agreement. This Certificate is issued under and is
subject to the terms, provisions and conditions of the Agreement, to which
Agreement the Holder of this Certificate by virtue of the acceptance hereof
assents and by which such Holder is bound.

      Pursuant to the terms of the Agreement, a distribution will be made on the
25th day of each month or, if such 25th day is not a Business Day, the Business
Day immediately following (the "Distribution Date"), commencing on the first
Distribution Date specified above, to the Person in whose name this Certificate
is registered at the close of business on the Record Date, in an amount equal to
the product of the Percentage Interest evidenced by this Certificate and,
subject to the prior rights of the Group I-A Certificates and each Class of
Class B Certificates of the related Group bearing a lower numerical designation
as specified in the Agreement, any Class I-B-2 Distribution Amount required to
be distributed to Holders of the Class I-B-2 Certificates on such Distribution
Date, subject to adjustment, in certain events, as specified in the Agreement.
The pass-through rate on the Class I-B-2 Certificates applicable to each
Distribution Date will be 5.750% per annum. The amount of interest which accrues
on this Certificate in any month will be subject to reduction with respect to
any Non-Supported Interest Shortfall and any Relief Act Shortfall allocated to
the Class I-B-2 Certificates, as described in the Agreement.

      Distributions on this Certificate will be made by the Paying Agent by
check mailed to the address of the Person entitled thereto, as such name and
address shall appear on the Certificate Register, unless such Person is entitled
to receive payments by wire transfer in immediately available funds in
accordance with the Agreement and such Person has notified the Paying Agent
pursuant to the Agreement that such payments are to be made by wire transfer of
immediately available funds. Notwithstanding the above, the final distribution
in reduction of the Principal Balance of this Certificate will be made after due
notice of the pendency of such distribution and only upon presentation and
surrender of this Certificate at the office or agency of the Paying Agent
specified for that purpose in the notice of final distribution.

      Reference is hereby made to the further provisions of this Certificate set
forth on the reverse hereof, which further provisions shall for all purposes
have the same effect as if set forth at this place.

      This Certificate constitutes a "regular interest" in a "real estate
mortgage investment conduit" as those terms are defined in Section 860G(a)(1)
and Section 860D, respectively, of the Internal Revenue Code of 1986, as
amended.

      Unless this Certificate has been countersigned by an authorized officer of
the Authenticating Agent, by manual signature, this Certificate shall not be
entitled to any benefit under the Agreement or be valid for any purpose.


<PAGE>

            IN WITNESS WHEREOF, the Paying Agent has caused this Certificate to
be duly executed as of the date set forth below.

Dated:

                                       Wells Fargo Bank, N.A.,
                                            Paying Agent

                                       By____________________________
                                            Authorized Officer

Countersigned:

Wells Fargo Bank, N.A.,
  Authenticating Agent

By ________________________
   Authorized Officer


<PAGE>

                                  EXHIBIT I-B-3

                    [FORM OF FACE OF CLASS I-B-3 CERTIFICATE]

THIS CERTIFICATE IS SUBORDINATED IN RIGHT OF PAYMENT TO THE GROUP I-A
CERTIFICATES, THE CLASS I-B-1 CERTIFICATES AND THE CLASS I-B-2 CERTIFICATES AS
DESCRIBED IN THE AGREEMENT REFERRED TO HEREIN.

[UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE
DEPOSITORY TRUST COMPANY TO THE DEPOSITOR OR ITS AGENT FOR REGISTRATION OF
TRANSFER, EXCHANGE OR PAYMENT, AND ANY CERTIFICATE ISSUED IS REGISTERED IN THE
NAME OF CEDE & CO. OR SUCH OTHER NAME AS REQUESTED BY AN AUTHORIZED
REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY AND ANY PAYMENT IS MADE TO CEDE &
CO., ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO
ANY PERSON IS WRONGFUL SINCE THE REGISTERED OWNER HEREOF, CEDE & CO., HAS AN
INTEREST HEREIN.]

                        MORTGAGE PASS-THROUGH CERTIFICATE
                           SERIES 2006-4, CLASS I-B-3

 evidencing an interest in a pool of fixed interest rate, monthly pay, fully
amortizing, first lien, one- to four-family residential mortgage loans sold by

                    WELLS FARGO ASSET SECURITIES CORPORATION
               (Not an interest in or obligation of the Depositor)

            THIS CERTIFICATE DOES NOT EVIDENCE AN OBLIGATION OF, OR AN INTEREST
IN, THE DEPOSITOR, THE MASTER SERVICER, THE TRUSTEE OR ANY OF THEIR AFFILIATES,
AND IS NOT INSURED OR GUARANTEED BY THE DEPOSITOR, THE MASTER SERVICER, THE
TRUSTEE OR ANY OF THEIR AFFILIATES, OR BY ANY GOVERNMENT AGENCY OR PRIVATE
INSURER.

            DISTRIBUTIONS IN REDUCTION OF THE PRINCIPAL BALANCE OF THIS
CERTIFICATE WILL BE MADE IN THE MANNER DESCRIBED IN THE AGREEMENT. ACCORDINGLY,
THE OUTSTANDING PRINCIPAL BALANCE OF THIS CERTIFICATE AT ANY TIME MAY BE LESS
THAN THE INITIAL PRINCIPAL BALANCE REPRESENTED HEREBY.

Certificate No.                        Cut-Off Date:  March 1, 2006

CUSIP No.:  94983B AY 5                First Distribution Date: April 25, 2006

ISIN No.: US94983BAY56                 Denomination:  $

Percentage Interest evidenced          Final Scheduled Maturity Date:  April 25,
by this Certificate: %                 2036


      THIS CERTIFIES THAT _______________________________ is the registered
owner of the Percentage Interest evidenced by this Certificate in monthly
distributions to the Holders of the Class I-B-3 Certificates with respect to a
Trust Estate consisting of a pool of fixed interest rate, monthly pay, fully
amortizing, first lien, one- to four-family residential mortgage loans, other
than the Fixed Retained Yield, if any, with respect thereto, consisting of two
loan groups (the "Group I Mortgage Loans" and "Group II Mortgage Loans,"
respectively), formed by Wells Fargo Asset Securities Corporation (hereinafter
called the "Depositor," which term includes any successor entity under the
Agreement referred to below). The Trust Estate was created pursuant to a Pooling
and Servicing Agreement dated as of March 30, 2006 (the "Agreement") among the
Depositor, Wells Fargo Bank, N.A., as master servicer (the "Master Servicer")
and U.S. Bank National Association, as trustee (the "Trustee"), a summary of
certain of the pertinent provisions of which is set forth hereinafter. To the
extent not defined herein, the capitalized terms used herein have the meanings
ascribed to such terms in the Agreement. This Certificate is issued under and is
subject to the terms, provisions and conditions of the Agreement, to which
Agreement the Holder of this Certificate by virtue of the acceptance hereof
assents and by which such Holder is bound.

      Pursuant to the terms of the Agreement, a distribution will be made on the
25th day of each month or, if such 25th day is not a Business Day, the Business
Day immediately following (the "Distribution Date"), commencing on the first
Distribution Date specified above, to the Person in whose name this Certificate
is registered at the close of business on the Record Date, in an amount equal to
the product of the Percentage Interest evidenced by this Certificate and,
subject to the prior rights of the Group I-A Certificates and each Class of
Class B Certificates of the related Group bearing a lower numerical designation
as specified in the Agreement, any Class I-B-3 Distribution Amount required to
be distributed to Holders of the Class I-B-3 Certificates on such Distribution
Date, subject to adjustment, in certain events, as specified in the Agreement.
The pass-through rate on the Class I-B-3 Certificates applicable to each
Distribution Date will be 5.750% per annum. The amount of interest which accrues
on this Certificate in any month will be subject to reduction with respect to
any Non-Supported Interest Shortfall and any Relief Act Shortfall allocated to
the Class I-B-3 Certificates, as described in the Agreement.

      Distributions on this Certificate will be made by the Paying Agent by
check mailed to the address of the Person entitled thereto, as such name and
address shall appear on the Certificate Register, unless such Person is entitled
to receive payments by wire transfer in immediately available funds in
accordance with the Agreement and such Person has notified the Paying Agent
pursuant to the Agreement that such payments are to be made by wire transfer of
immediately available funds. Notwithstanding the above, the final distribution
in reduction of the Principal Balance of this Certificate will be made after due
notice of the pendency of such distribution and only upon presentation and
surrender of this Certificate at the office or agency of the Paying Agent
specified for that purpose in the notice of final distribution.

      Reference is hereby made to the further provisions of this Certificate set
forth on the reverse hereof, which further provisions shall for all purposes
have the same effect as if set forth at this place.

      This Certificate constitutes a "regular interest" in a "real estate
mortgage investment conduit" as those terms are defined in Section 860G(a)(1)
and Section 860D, respectively, of the Internal Revenue Code of 1986, as
amended.

      Unless this Certificate has been countersigned by an authorized officer of
the Authenticating Agent, by manual signature, this Certificate shall not be
entitled to any benefit under the Agreement or be valid for any purpose.


<PAGE>

            IN WITNESS WHEREOF, the Paying Agent has caused this Certificate to
be duly executed as of the date set forth below.

Dated:

                                       Wells Fargo Bank, N.A.,
                                            Paying Agent

                                       By____________________________
                                            Authorized Officer

Countersigned:

Wells Fargo Bank, N.A.,
  Authenticating Agent

By ________________________
   Authorized Officer


<PAGE>

                                  EXHIBIT I-B-4
                    [FORM OF FACE OF CLASS I-B-4 CERTIFICATE]

THIS CERTIFICATE IS SUBORDINATED IN RIGHT OF PAYMENT TO THE GROUP I-A
CERTIFICATES, THE CLASS I-B-1 CERTIFICATES, THE CLASS I-B-2 CERTIFICATES AND THE
CLASS I-B-3 CERTIFICATES AS DESCRIBED IN THE AGREEMENT REFERRED TO HEREIN.

THIS CERTIFICATE HAS NOT BEEN AND WILL NOT BE REGISTERED UNDER THE SECURITIES
ACT OF 1933, AS AMENDED, OR THE SECURITIES LAWS OF ANY STATE AND MAY NOT BE
RESOLD OR TRANSFERRED UNLESS IT IS REGISTERED PURSUANT TO SUCH ACT AND LAWS OR
IS SOLD OR TRANSFERRED IN TRANSACTIONS WHICH ARE EXEMPT FROM REGISTRATION UNDER
SUCH ACT AND UNDER APPLICABLE STATE LAW AND IS TRANSFERRED IN ACCORDANCE WITH
THE PROVISIONS OF SECTION 5.02 OF THE AGREEMENT REFERRED TO HEREIN.

EXCEPT AS PROVIDED IN SECTION 5.02(C) OF THE AGREEMENT REFERRED TO HEREIN, THIS
CERTIFICATE MAY NOT BE PURCHASED BY OR TRANSFERRED TO ANY PERSON THAT HAS NOT
DELIVERED A REPRESENTATION LETTER STATING EITHER (A) THAT THE TRANSFEREE IS NOT
AN EMPLOYEE BENEFIT PLAN OR OTHER RETIREMENT ARRANGEMENT SUBJECT TO TITLE I OF
THE EMPLOYEE RETIREMENT INCOME SECURITY ACT OF 1974, AS AMENDED ("ERISA"), OR
SECTION 4975 OF THE INTERNAL REVENUE CODE OF 1986, AS AMENDED (THE "CODE"), OR A
GOVERNMENTAL PLAN, AS DEFINED IN SECTION 3(32) OF ERISA, SUBJECT TO ANY FEDERAL,
STATE OR LOCAL LAW WHICH IS, TO A MATERIAL EXTENT, SIMILAR TO THE FOREGOING
PROVISIONS OF ERISA OR THE CODE (COLLECTIVELY, A "PLAN"), AND IS NOT ACTING ON
BEHALF OF OR INVESTING THE ASSETS OF A PLAN OR (B) SUBJECT TO CERTAIN CONDITIONS
SET FORTH IN THE AGREEMENT, THAT THE SOURCE OF FUNDS USED TO PURCHASE THIS
CERTIFICATE IS AN "INSURANCE COMPANY GENERAL ACCOUNT."


                        MORTGAGE PASS-THROUGH CERTIFICATE
                           SERIES 2006-4, CLASS I-B-4

 evidencing an interest in a pool of fixed interest rate, monthly pay, fully
amortizing, first lien, one- to four-family residential mortgage loans sold by

                   WELLS FARGO ASSET SECURITIES CORPORATION
             (Not an interest in or obligation of the Depositor)

            THIS CERTIFICATE DOES NOT EVIDENCE AN OBLIGATION OF, OR AN INTEREST
IN, THE DEPOSITOR, THE MASTER SERVICER, THE TRUSTEE OR ANY OF THEIR AFFILIATES,
AND IS NOT INSURED OR GUARANTEED BY THE DEPOSITOR, THE MASTER SERVICER, THE
TRUSTEE OR ANY OF THEIR AFFILIATES, OR BY ANY GOVERNMENT AGENCY OR PRIVATE
INSURER.

            DISTRIBUTIONS IN REDUCTION OF THE PRINCIPAL BALANCE OF THIS
CERTIFICATE WILL BE MADE IN THE MANNER DESCRIBED IN THE AGREEMENT. ACCORDINGLY,
THE OUTSTANDING PRINCIPAL BALANCE OF THIS CERTIFICATE AT ANY TIME MAY BE LESS
THAN THE INITIAL PRINCIPAL BALANCE REPRESENTED HEREBY.

Certificate No.                        Cut-Off Date:  March 1, 2006

CUSIP No.: 94983B BC 2                 First Distribution Date: April 25, 2006

ISIN No.: US94983BBC28                 Denomination:  $

Percentage Interest evidenced          Final Scheduled Maturity Date:  April 25,
by this Certificate: %                 2036


      THIS CERTIFIES THAT ____________________________ is the registered owner
of the Percentage Interest evidenced by this Certificate in monthly
distributions to the Holders of the Class I-B-4 Certificates with respect to a
Trust Estate consisting of a pool of fixed interest rate, monthly pay, fully
amortizing, first lien, one- to four-family residential mortgage loans, other
than the Fixed Retained Yield, if any, with respect thereto, consisting of two
loan groups (the "Group I Mortgage Loans" and "Group II Mortgage Loans,"
respectively), formed by Wells Fargo Asset Securities Corporation (hereinafter
called the "Depositor," which term includes any successor entity under the
Agreement referred to below). The Trust Estate was created pursuant to a Pooling
and Servicing Agreement dated as of March 30, 2006 (the "Agreement") among the
Depositor, Wells Fargo Bank, N.A., as master servicer (the "Master Servicer")
and U.S. Bank National Association, as trustee (the "Trustee"), a summary of
certain of the pertinent provisions of which is set forth hereinafter. To the
extent not defined herein, the capitalized terms used herein have the meanings
ascribed to such terms in the Agreement. This Certificate is issued under and is
subject to the terms, provisions and conditions of the Agreement, to which
Agreement the Holder of this Certificate by virtue of the acceptance hereof
assents and by which such Holder is bound.

      Pursuant to the terms of the Agreement, a distribution will be made on the
25th day of each month or, if such 25th day is not a Business Day, the Business
Day immediately following (the "Distribution Date"), commencing on the first
Distribution Date specified above, to the Person in whose name this Certificate
is registered at the close of business on the Record Date, in an amount equal to
the product of the Percentage Interest evidenced by this Certificate and,
subject to the prior rights of the Group I-A Certificates and each Class of
Class B Certificates of the related Group bearing a lower numerical designation
as specified in the Agreement, any Class I-B-4 Distribution Amount required to
be distributed to Holders of the Class I-B-4 Certificates on such Distribution
Date, subject to adjustment, in certain events, as specified in the Agreement.
The pass-through rate on the Class I-B-4 Certificates applicable to each
Distribution Date will be 5.750% per annum. The amount of interest which accrues
on this Certificate in any month will be subject to reduction with respect to
any Non-Supported Interest Shortfall and any Relief Act Shortfall allocated to
the Class I-B-4 Certificates, as described in the Agreement.

      Distributions on this Certificate will be made by the Paying Agent by
check mailed to the address of the Person entitled thereto, as such name and
address shall appear on the Certificate Register, unless such Person is entitled
to receive payments by wire transfer in immediately available funds in
accordance with the Agreement and such Person has notified the Paying Agent
pursuant to the Agreement that such payments are to be made by wire transfer of
immediately available funds. Notwithstanding the above, the final distribution
in reduction of the Principal Balance of this Certificate will be made after due
notice of the pendency of such distribution and only upon presentation and
surrender of this Certificate at the office or agency of the Paying Agent
specified for that purpose in the notice of final distribution.

      No transfer of a Class I-B-4 Certificate will be made unless such transfer
is exempt from the registration requirements of the Securities Act of 1933, as
amended, and any applicable state securities laws or is made in accordance with
said Act and laws. In the event that such a transfer is desired to be made by
the Holder hereof, (i) the transferee will be required to execute an investment
letter in the form described in the Agreement and (ii) if such transfer is to be
made within three years from the later of (a) the date of initial issuance of
the Certificates or (b) the last date on which the Depositor or any affiliate
thereof was a Holder of the Certificates proposed to be transferred, and unless
such transfer is made in reliance on Rule 144A of the Securities Act of 1933, as
amended, the Master Servicer or the Depositor may require the Holder to deliver
an opinion of counsel acceptable to and in form and substance satisfactory to
the Master Servicer and the Depositor that such transfer is exempt (describing
the applicable exemption and the basis therefor) from or is being made pursuant
to the registration requirements of the Securities Act of 1933, as amended, and
of any applicable statute of any state. The Holder hereof desiring to effect
such transfer shall, and does hereby agree to, indemnify the Trustee, the
Depositor, the Master Servicer, and any Paying Agent against any liability that
may result if the transfer is not so exempt or is not made in accordance with
such Federal and state laws. In connection with any such transfer, the Master
Servicer will also require (i) a representation letter, in the form as described
in the Agreement, stating either (a) that the transferee is not a Plan and is
not acting on behalf of a Plan or using the assets of a Plan to effect such
purchase or (b) subject to certain conditions described in the Agreement, that
the source of funds used to purchase this Certificate is an "insurance company
general account," or (ii) if such transferee is a Plan, (a) an opinion of
counsel acceptable to and in form and substance satisfactory to the Master
Servicer and the Depositor with respect to certain matters and (b) such other
documentation as the Depositor or the Master Servicer may require, as described
in the Agreement.

      Reference is hereby made to the further provisions of this Certificate set
forth on the reverse hereof, which further provisions shall for all purposes
have the same effect as if set forth at this place.

      This Certificate constitutes a "regular interest" in a "real estate
mortgage investment conduit" as those terms are defined in Section 860G(a)(1)
and Section 860D, respectively, of the Internal Revenue Code of 1986, as
amended.

      Unless this Certificate has been countersigned by an authorized officer of
the Authenticating Agent, by manual signature, this Certificate shall not be
entitled to any benefit under the Agreement or be valid for any purpose.


<PAGE>

            IN WITNESS WHEREOF, the Paying Agent has caused this Certificate to
be duly executed as of the date set forth below.

Dated:

                                       Wells Fargo Bank, N.A.,
                                            Paying Agent

                                       By____________________________
                                            Authorized Officer

Countersigned:

Wells Fargo Bank, N.A.,
  Authenticating Agent

By ________________________
   Authorized Officer


<PAGE>

                                  EXHIBIT I-B-5
                    [FORM OF FACE OF CLASS I-B-5 CERTIFICATE]

THIS CERTIFICATE IS SUBORDINATED IN RIGHT OF PAYMENT TO THE GROUP I-A
CERTIFICATES, THE CLASS I-B-1 CERTIFICATES, THE CLASS I-B-2 CERTIFICATES, THE
CLASS I-B-3 CERTIFICATES AND THE CLASS I-B-4 CERTIFICATES AS DESCRIBED IN THE
AGREEMENT REFERRED TO HEREIN.

THIS CERTIFICATE HAS NOT BEEN AND WILL NOT BE REGISTERED UNDER THE SECURITIES
ACT OF 1933, AS AMENDED, OR THE SECURITIES LAWS OF ANY STATE AND MAY NOT BE
RESOLD OR TRANSFERRED UNLESS IT IS REGISTERED PURSUANT TO SUCH ACT AND LAWS OR
IS SOLD OR TRANSFERRED IN TRANSACTIONS WHICH ARE EXEMPT FROM REGISTRATION UNDER
SUCH ACT AND UNDER APPLICABLE STATE LAW AND IS TRANSFERRED IN ACCORDANCE WITH
THE PROVISIONS OF SECTION 5.02 OF THE AGREEMENT REFERRED TO HEREIN.

EXCEPT AS PROVIDED IN SECTION 5.02(C) OF THE AGREEMENT REFERRED TO HEREIN, THIS
CERTIFICATE MAY NOT BE PURCHASED BY OR TRANSFERRED TO ANY PERSON THAT HAS NOT
DELIVERED A REPRESENTATION LETTER STATING EITHER (A) THAT THE TRANSFEREE IS NOT
AN EMPLOYEE BENEFIT PLAN OR OTHER RETIREMENT ARRANGEMENT SUBJECT TO TITLE I OF
THE EMPLOYEE RETIREMENT INCOME SECURITY ACT OF 1974, AS AMENDED ("ERISA"), OR
SECTION 4975 OF THE INTERNAL REVENUE CODE OF 1986, AS AMENDED (THE "CODE"), OR A
GOVERNMENTAL PLAN, AS DEFINED IN SECTION 3(32) OF ERISA, SUBJECT TO ANY FEDERAL,
STATE OR LOCAL LAW WHICH IS, TO A MATERIAL EXTENT, SIMILAR TO THE FOREGOING
PROVISIONS OF ERISA OR THE CODE (COLLECTIVELY, A "PLAN"), AND IS NOT ACTING ON
BEHALF OF OR INVESTING THE ASSETS OF A PLAN OR (B) SUBJECT TO CERTAIN CONDITIONS
SET FORTH IN THE AGREEMENT, THAT THE SOURCE OF FUNDS USED TO PURCHASE THIS
CERTIFICATE IS AN "INSURANCE COMPANY GENERAL ACCOUNT."


                        MORTGAGE PASS-THROUGH CERTIFICATE
                           SERIES 2006-4, CLASS I-B-5

 evidencing an interest in a pool of fixed interest rate, monthly pay, fully
amortizing, first lien, one- to four-family residential mortgage loans sold by

                    WELLS FARGO ASSET SECURITIES CORPORATION
               (Not an interest in or obligation of the Depositor)

            THIS CERTIFICATE DOES NOT EVIDENCE AN OBLIGATION OF, OR AN INTEREST
IN, THE DEPOSITOR, THE MASTER SERVICER, THE TRUSTEE OR ANY OF THEIR AFFILIATES,
AND IS NOT INSURED OR GUARANTEED BY THE DEPOSITOR, THE MASTER SERVICER, THE
TRUSTEE OR ANY OF THEIR AFFILIATES, OR BY ANY GOVERNMENT AGENCY OR PRIVATE
INSURER.

            DISTRIBUTIONS IN REDUCTION OF THE PRINCIPAL BALANCE OF THIS
CERTIFICATE WILL BE MADE IN THE MANNER DESCRIBED IN THE AGREEMENT. ACCORDINGLY,
THE OUTSTANDING PRINCIPAL BALANCE OF THIS CERTIFICATE AT ANY TIME MAY BE LESS
THAN THE INITIAL PRINCIPAL BALANCE REPRESENTED HEREBY.

Certificate No.                        Cut-Off Date:  March 1, 2006

CUSIP No.: 94983B BD 0                 First Distribution Date: April 25, 2006

ISIN No.: US94983BBD01                 Denomination:  $

Percentage Interest evidenced          Final Scheduled Maturity Date:  April 25,
by this Certificate: %                 2036


      THIS CERTIFIES THAT ____________________________ is the registered owner
of the Percentage Interest evidenced by this Certificate in monthly
distributions to the Holders of the Class I-B-5 Certificates with respect to a
Trust Estate consisting of a pool of fixed interest rate, monthly pay, fully
amortizing, first lien, one- to four-family residential mortgage loans, other
than the Fixed Retained Yield, if any, with respect thereto, consisting of two
loan groups (the "Group I Mortgage Loans" and "Group II Mortgage Loans,"
respectively), formed by Wells Fargo Asset Securities Corporation (hereinafter
called the "Depositor," which term includes any successor entity under the
Agreement referred to below). The Trust Estate was created pursuant to a Pooling
and Servicing Agreement dated as of March 30, 2006 (the "Agreement") among the
Depositor, Wells Fargo Bank, N.A., as master servicer (the "Master Servicer")
and U.S. Bank National Association, as trustee (the "Trustee"), a summary of
certain of the pertinent provisions of which is set forth hereinafter. To the
extent not defined herein, the capitalized terms used herein have the meanings
ascribed to such terms in the Agreement. This Certificate is issued under and is
subject to the terms, provisions and conditions of the Agreement, to which
Agreement the Holder of this Certificate by virtue of the acceptance hereof
assents and by which such Holder is bound.

      Pursuant to the terms of the Agreement, a distribution will be made on the
25th day of each month or, if such 25th day is not a Business Day, the Business
Day immediately following (the "Distribution Date"), commencing on the first
Distribution Date specified above, to the Person in whose name this Certificate
is registered at the close of business on the Record Date, in an amount equal to
the product of the Percentage Interest evidenced by this Certificate and,
subject to the prior rights of the Group I-A Certificates and each Class of
Class B Certificates of the related Group bearing a lower numerical designation
as specified in the Agreement, any Class I-B-5 Distribution Amount required to
be distributed to Holders of the Class I-B-5 Certificates on such Distribution
Date, subject to adjustment, in certain events, as specified in the Agreement.
The pass-through rate on the Class I-B-5 Certificates applicable to each
Distribution Date will be 5.750% per annum. The amount of interest which accrues
on this Certificate in any month will be subject to reduction with respect to
any Non-Supported Interest Shortfall and any Relief Act Shortfall allocated to
the Class I-B-5 Certificates, as described in the Agreement.

      Distributions on this Certificate will be made by the Paying Agent by
check mailed to the address of the Person entitled thereto, as such name and
address shall appear on the Certificate Register, unless such Person is entitled
to receive payments by wire transfer in immediately available funds in
accordance with the Agreement and such Person has notified the Paying Agent
pursuant to the Agreement that such payments are to be made by wire transfer of
immediately available funds. Notwithstanding the above, the final distribution
in reduction of the Principal Balance of this Certificate will be made after due
notice of the pendency of such distribution and only upon presentation and
surrender of this Certificate at the office or agency of the Paying Agent
specified for that purpose in the notice of final distribution.

      No transfer of a Class I-B-5 Certificate will be made unless such transfer
is exempt from the registration requirements of the Securities Act of 1933, as
amended, and any applicable state securities laws or is made in accordance with
said Act and laws. In the event that such a transfer is desired to be made by
the Holder hereof, (i) the transferee will be required to execute an investment
letter in the form described in the Agreement and (ii) if such transfer is to be
made within three years from the later of (a) the date of initial issuance of
the Certificates or (b) the last date on which the Depositor or any affiliate
thereof was a Holder of the Certificates proposed to be transferred, and unless
such transfer is made in reliance on Rule 144A of the Securities Act of 1933, as
amended, the Master Servicer or the Depositor may require the Holder to deliver
an opinion of counsel acceptable to and in form and substance satisfactory to
the Master Servicer and the Depositor that such transfer is exempt (describing
the applicable exemption and the basis therefor) from or is being made pursuant
to the registration requirements of the Securities Act of 1933, as amended, and
of any applicable statute of any state. The Holder hereof desiring to effect
such transfer shall, and does hereby agree to, indemnify the Trustee, the
Depositor, the Master Servicer, and any Paying Agent against any liability that
may result if the transfer is not so exempt or is not made in accordance with
such Federal and state laws. In connection with any such transfer, the Master
Servicer will also require (i) a representation letter, in the form as described
in the Agreement, stating either (a) that the transferee is not a Plan and is
not acting on behalf of a Plan or using the assets of a Plan to effect such
purchase or (b) subject to certain conditions described in the Agreement, that
the source of funds used to purchase this Certificate is an "insurance company
general account," or (ii) if such transferee is a Plan, (a) an opinion of
counsel acceptable to and in form and substance satisfactory to the Master
Servicer and the Depositor with respect to certain matters and (b) such other
documentation as the Depositor or the Master Servicer may require, as described
in the Agreement.

      Reference is hereby made to the further provisions of this Certificate set
forth on the reverse hereof, which further provisions shall for all purposes
have the same effect as if set forth at this place.

      This Certificate constitutes a "regular interest" in a "real estate
mortgage investment conduit" as those terms are defined in Section 860G(a)(1)
and Section 860D, respectively, of the Internal Revenue Code of 1986, as
amended.

      Unless this Certificate has been countersigned by an authorized officer of
the Authenticating Agent, by manual signature, this Certificate shall not be
entitled to any benefit under the Agreement or be valid for any purpose.


<PAGE>

            IN WITNESS WHEREOF, the Paying Agent has caused this Certificate to
be duly executed as of the date set forth below.

Dated:

                                       Wells Fargo Bank, N.A.,
                                            Paying Agent

                                       By____________________________
                                            Authorized Officer

Countersigned:

Wells Fargo Bank, N.A.,
  Authenticating Agent

By ________________________
   Authorized Officer


<PAGE>

                                EXHIBIT I-B-6
                  [FORM OF FACE OF CLASS I-B-6 CERTIFICATE]

THIS CERTIFICATE IS SUBORDINATED IN RIGHT OF PAYMENT TO THE GROUP I-A
CERTIFICATES, THE CLASS I-B-1 CERTIFICATES, THE CLASS I-B-2 CERTIFICATES, THE
CLASS I-B-3 CERTIFICATES, THE CLASS I-B-4 CERTIFICATES AND THE CLASS I-B-5
CERTIFICATES AS DESCRIBED IN THE AGREEMENT REFERRED TO HEREIN.

THIS CERTIFICATE HAS NOT BEEN AND WILL NOT BE REGISTERED UNDER THE SECURITIES
ACT OF 1933, AS AMENDED, OR THE SECURITIES LAWS OF ANY STATE AND MAY NOT BE
RESOLD OR TRANSFERRED UNLESS IT IS REGISTERED PURSUANT TO SUCH ACT AND LAWS OR
IS SOLD OR TRANSFERRED IN TRANSACTIONS WHICH ARE EXEMPT FROM REGISTRATION UNDER
SUCH ACT AND UNDER APPLICABLE STATE LAW AND IS TRANSFERRED IN ACCORDANCE WITH
THE PROVISIONS OF SECTION 5.02 OF THE AGREEMENT REFERRED TO HEREIN.

EXCEPT AS PROVIDED IN SECTION 5.02(C) OF THE AGREEMENT REFERRED TO HEREIN, THIS
CERTIFICATE MAY NOT BE PURCHASED BY OR TRANSFERRED TO ANY PERSON THAT HAS NOT
DELIVERED A REPRESENTATION LETTER STATING EITHER (A) THAT THE TRANSFEREE IS NOT
AN EMPLOYEE BENEFIT PLAN OR OTHER RETIREMENT ARRANGEMENT SUBJECT TO TITLE I OF
THE EMPLOYEE RETIREMENT INCOME SECURITY ACT OF 1974, AS AMENDED ("ERISA"), OR
SECTION 4975 OF THE INTERNAL REVENUE CODE OF 1986, AS AMENDED (THE "CODE"), OR A
GOVERNMENTAL PLAN, AS DEFINED IN SECTION 3(32) OF ERISA, SUBJECT TO ANY FEDERAL,
STATE OR LOCAL LAW WHICH IS, TO A MATERIAL EXTENT, SIMILAR TO THE FOREGOING
PROVISIONS OF ERISA OR THE CODE (COLLECTIVELY, A "PLAN"), AND IS NOT ACTING ON
BEHALF OF OR INVESTING THE ASSETS OF A PLAN OR (B) SUBJECT TO CERTAIN CONDITIONS
SET FORTH IN THE AGREEMENT, THAT THE SOURCE OF FUNDS USED TO PURCHASE THIS
CERTIFICATE IS AN "INSURANCE COMPANY GENERAL ACCOUNT."


<PAGE>

                        MORTGAGE PASS-THROUGH CERTIFICATE
                           SERIES 2006-4, CLASS I-B-6

 evidencing an interest in a pool of fixed interest rate, monthly pay, fully
amortizing, first lien, one- to four-family residential mortgage loans sold by

                   WELLS FARGO ASSET SECURITIES CORPORATION
             (Not an interest in or obligation of the Depositor)

            THIS CERTIFICATE DOES NOT EVIDENCE AN OBLIGATION OF, OR AN INTEREST
IN, THE DEPOSITOR, THE MASTER SERVICER, THE TRUSTEE OR ANY OF THEIR AFFILIATES,
AND IS NOT INSURED OR GUARANTEED BY THE DEPOSITOR, THE MASTER SERVICER, THE
TRUSTEE OR ANY OF THEIR AFFILIATES, OR BY ANY GOVERNMENT AGENCY OR PRIVATE
INSURER.

            DISTRIBUTIONS IN REDUCTION OF THE PRINCIPAL BALANCE OF THIS
CERTIFICATE WILL BE MADE IN THE MANNER DESCRIBED IN THE AGREEMENT. ACCORDINGLY,
THE OUTSTANDING PRINCIPAL BALANCE OF THIS CERTIFICATE AT ANY TIME MAY BE LESS
THAN THE INITIAL PRINCIPAL BALANCE REPRESENTED HEREBY.

Certificate No.                        Cut-Off Date:  March 1, 2006

CUSIP No.: 94983B BE 8                 First Distribution Date: April 25, 2006

ISIN No.: US94983BBE83                 Denomination:  $

Percentage Interest evidenced          Final Scheduled Maturity Date:  April 25,
by this Certificate: %                 2036


      THIS CERTIFIES THAT ____________________________ is the registered owner
of the Percentage Interest evidenced by this Certificate in monthly
distributions to the Holders of the Class I-B-6 Certificates with respect to a
Trust Estate consisting of a pool of fixed interest rate, monthly pay, fully
amortizing, first lien, one- to four-family residential mortgage loans, other
than the Fixed Retained Yield, if any, with respect thereto, consisting of two
loan groups (the "Group I Mortgage Loans" and "Group II Mortgage Loans,"
respectively), formed by Wells Fargo Asset Securities Corporation (hereinafter
called the "Depositor," which term includes any successor entity under the
Agreement referred to below). The Trust Estate was created pursuant to a Pooling
and Servicing Agreement dated as of March 30, 2006 (the "Agreement") among the
Depositor, Wells Fargo Bank, N.A., as master servicer (the "Master Servicer")
and U.S. Bank National Association, as trustee (the "Trustee"), a summary of
certain of the pertinent provisions of which is set forth hereinafter. To the
extent not defined herein, the capitalized terms used herein have the meanings
ascribed to such terms in the Agreement. This Certificate is issued under and is
subject to the terms, provisions and conditions of the Agreement, to which
Agreement the Holder of this Certificate by virtue of the acceptance hereof
assents and by which such Holder is bound.

      Pursuant to the terms of the Agreement, a distribution will be made on the
25th day of each month or, if such 25th day is not a Business Day, the Business
Day immediately following (the "Distribution Date"), commencing on the first
Distribution Date specified above, to the Person in whose name this Certificate
is registered at the close of business on the Record Date, in an amount equal to
the product of the Percentage Interest evidenced by this Certificate and,
subject to the prior rights of the Group I-A Certificates and each Class of
Class B Certificates of the related Group bearing a lower numerical designation
as specified in the Agreement, any Class I-B-6 Distribution Amount required to
be distributed to Holders of the Class I-B-6 Certificates on such Distribution
Date, subject to adjustment, in certain events, as specified in the Agreement.
The pass-through rate on the Class I-B-6 Certificates applicable to each
Distribution Date will be 5.750% per annum. The amount of interest which accrues
on this Certificate in any month will be subject to reduction with respect to
any Non-Supported Interest Shortfall and any Relief Act Shortfall allocated to
the Class I-B-6 Certificates, as described in the Agreement.

      Distributions on this Certificate will be made by the Paying Agent by
check mailed to the address of the Person entitled thereto, as such name and
address shall appear on the Certificate Register, unless such Person is entitled
to receive payments by wire transfer in immediately available funds in
accordance with the Agreement and such Person has notified the Paying Agent
pursuant to the Agreement that such payments are to be made by wire transfer of
immediately available funds. Notwithstanding the above, the final distribution
in reduction of the Principal Balance of this Certificate will be made after due
notice of the pendency of such distribution and only upon presentation and
surrender of this Certificate at the office or agency of the Paying Agent
specified for that purpose in the notice of final distribution.

      No transfer of a Class I-B-6 Certificate will be made unless such transfer
is exempt from the registration requirements of the Securities Act of 1933, as
amended, and any applicable state securities laws or is made in accordance with
said Act and laws. In the event that such a transfer is desired to be made by
the Holder hereof, (i) the transferee will be required to execute an investment
letter in the form described in the Agreement and (ii) if such transfer is to be
made within three years from the later of (a) the date of initial issuance of
the Certificates or (b) the last date on which the Depositor or any affiliate
thereof was a Holder of the Certificates proposed to be transferred, and unless
such transfer is made in reliance on Rule 144A of the Securities Act of 1933, as
amended, the Master Servicer or the Depositor may require the Holder to deliver
an opinion of counsel acceptable to and in form and substance satisfactory to
the Master Servicer and the Depositor that such transfer is exempt (describing
the applicable exemption and the basis therefor) from or is being made pursuant
to the registration requirements of the Securities Act of 1933, as amended, and
of any applicable statute of any state. The Holder hereof desiring to effect
such transfer shall, and does hereby agree to, indemnify the Trustee, the
Depositor, the Master Servicer, and any Paying Agent against any liability that
may result if the transfer is not so exempt or is not made in accordance with
such Federal and state laws. In connection with any such transfer, the Master
Servicer will also require (i) a representation letter, in the form as described
in the Agreement, stating either (a) that the transferee is not a Plan and is
not acting on behalf of a Plan or using the assets of a Plan to effect such
purchase or (b) subject to certain conditions described in the Agreement, that
the source of funds used to purchase this Certificate is an "insurance company
general account," or (ii) if such transferee is a Plan, (a) an opinion of
counsel acceptable to and in form and substance satisfactory to the Master
Servicer and the Depositor with respect to certain matters and (b) such other
documentation as the Depositor or the Master Servicer may require, as described
in the Agreement.

      Reference is hereby made to the further provisions of this Certificate set
forth on the reverse hereof, which further provisions shall for all purposes
have the same effect as if set forth at this place.

      This Certificate constitutes a "regular interest" in a "real estate
mortgage investment conduit" as those terms are defined in Section 860G(a)(1)
and Section 860D, respectively, of the Internal Revenue Code of 1986, as
amended.

      Unless this Certificate has been countersigned by an authorized officer of
the Authenticating Agent, by manual signature, this Certificate shall not be
entitled to any benefit under the Agreement or be valid for any purpose.


<PAGE>

            IN WITNESS WHEREOF, the Paying Agent has caused this Certificate to
be duly executed as of the date set forth below.

Dated:

                                       Wells Fargo Bank, N.A.,
                                            Paying Agent

                                       By____________________________
                                            Authorized Officer

Countersigned:

Wells Fargo Bank, N.A.,
  Authenticating Agent

By ________________________
   Authorized Officer


<PAGE>


                                EXHIBIT II-B-1
                  [FORM OF FACE OF CLASS II-B-1 CERTIFICATE]

THIS CERTIFICATE IS SUBORDINATED IN RIGHT OF PAYMENT TO THE GROUP II-A
CERTIFICATES AS DESCRIBED IN THE AGREEMENT REFERRED TO HEREIN.

[UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE
DEPOSITORY TRUST COMPANY TO THE DEPOSITOR OR ITS AGENT FOR REGISTRATION OF
TRANSFER, EXCHANGE OR PAYMENT, AND ANY CERTIFICATE ISSUED IS REGISTERED IN THE
NAME OF CEDE & CO. OR SUCH OTHER NAME AS REQUESTED BY AN AUTHORIZED
REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY AND ANY PAYMENT IS MADE TO CEDE &
CO., ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO
ANY PERSON IS WRONGFUL SINCE THE REGISTERED OWNER HEREOF, CEDE & CO., HAS AN
INTEREST HEREIN.]

                        MORTGAGE PASS-THROUGH CERTIFICATE
                           SERIES 2006-4, CLASS II-B-1

 evidencing an interest in a pool of fixed interest rate, monthly pay, fully
amortizing, first lien, one- to four-family residential mortgage loans sold by

                   WELLS FARGO ASSET SECURITIES CORPORATION
             (Not an interest in or obligation of the Depositor)

            THIS CERTIFICATE DOES NOT EVIDENCE AN OBLIGATION OF, OR AN INTEREST
IN, THE DEPOSITOR, THE MASTER SERVICER, THE TRUSTEE OR ANY OF THEIR AFFILIATES,
AND IS NOT INSURED OR GUARANTEED BY THE DEPOSITOR, THE MASTER SERVICER, THE
TRUSTEE OR ANY OF THEIR AFFILIATES, OR BY ANY GOVERNMENT AGENCY OR PRIVATE
INSURER.

            DISTRIBUTIONS IN REDUCTION OF THE PRINCIPAL BALANCE OF THIS
CERTIFICATE WILL BE MADE IN THE MANNER DESCRIBED IN THE AGREEMENT. ACCORDINGLY,
THE OUTSTANDING PRINCIPAL BALANCE OF THIS CERTIFICATE AT ANY TIME MAY BE LESS
THAN THE INITIAL PRINCIPAL BALANCE REPRESENTED HEREBY.

Certificate No.                        Cut-Off Date:  March 1, 2006

CUSIP No.: 94983B AZ 2                 First Distribution Date: April 25, 2006

ISIN No.: US94983BAZ22                 Denomination:  $

Percentage Interest evidenced          Final Scheduled Maturity Date:  April 25,
by this Certificate: %                 2036


      THIS CERTIFIES THAT ____________________________ is the registered owner
of the Percentage Interest evidenced by this Certificate in monthly
distributions to the Holders of the Class II-B-1 Certificates with respect to a
Trust Estate consisting of a pool of fixed interest rate, monthly pay, fully
amortizing, first lien, one- to four-family residential mortgage loans, other
than the Fixed Retained Yield, if any, with respect thereto, consisting of two
loan groups (the "Group I Mortgage Loans" and "Group II Mortgage Loans,"
respectively), formed by Wells Fargo Asset Securities Corporation (hereinafter
called the "Depositor," which term includes any successor entity under the
Agreement referred to below). The Trust Estate was created pursuant to a Pooling
and Servicing Agreement dated as of March 30, 2006 (the "Agreement") among the
Depositor, Wells Fargo Bank, N.A., as master servicer (the "Master Servicer")
and U.S. Bank National Association, as trustee (the "Trustee"), a summary of
certain of the pertinent provisions of which is set forth hereinafter. To the
extent not defined herein, the capitalized terms used herein have the meanings
ascribed to such terms in the Agreement. This Certificate is issued under and is
subject to the terms, provisions and conditions of the Agreement, to which
Agreement the Holder of this Certificate by virtue of the acceptance hereof
assents and by which such Holder is bound.

      Pursuant to the terms of the Agreement, a distribution will be made on the
25th day of each month or, if such 25th day is not a Business Day, the Business
Day immediately following (the "Distribution Date"), commencing on the first
Distribution Date specified above, to the Person in whose name this Certificate
is registered at the close of business on the Record Date, in an amount equal to
the product of the Percentage Interest evidenced by this Certificate and,
subject to the prior rights of the Group II-A Certificates as specified in the
Agreement, any Class II-B-1 Distribution Amount required to be distributed to
Holders of the Class II-B-1 Certificates on such Distribution Date, subject to
adjustment, in certain events, as specified in the Agreement. The pass-through
rate on the Class II-B-1 Certificates applicable to each Distribution Date will
be 5.750% per annum. The amount of interest which accrues on this Certificate in
any month will be subject to reduction with respect to any Non-Supported
Interest Shortfall and any Relief Act Shortfall allocated to the Class II-B-1
Certificates, as described in the Agreement.

      Distributions on this Certificate will be made by the Paying Agent by
check mailed to the address of the Person entitled thereto, as such name and
address shall appear on the Certificate Register, unless such Person is entitled
to receive payments by wire transfer in immediately available funds in
accordance with the Agreement and such Person has notified the Paying Agent
pursuant to the Agreement that such payments are to be made by wire transfer of
immediately available funds. Notwithstanding the above, the final distribution
in reduction of the Principal Balance of this Certificate will be made after due
notice of the pendency of such distribution and only upon presentation and
surrender of this Certificate at the office or agency of the Paying Agent
specified for that purpose in the notice of final distribution.

      Reference is hereby made to the further provisions of this Certificate set
forth on the reverse hereof, which further provisions shall for all purposes
have the same effect as if set forth at this place.

      This Certificate constitutes a "regular interest" in a "real estate
mortgage investment conduit" as those terms are defined in Section 860G(a)(1)
and Section 860D, respectively, of the Internal Revenue Code of 1986, as
amended.

      Unless this Certificate has been countersigned by an authorized officer of
the Authenticating Agent, by manual signature, this Certificate shall not be
entitled to any benefit under the Agreement or be valid for any purpose.


<PAGE>

            IN WITNESS WHEREOF, the Paying Agent has caused this Certificate to
be duly executed as of the date set forth below.

Dated:

                                       Wells Fargo Bank, N.A.,
                                            Paying Agent

                                       By____________________________
                                            Authorized Officer

Countersigned:

Wells Fargo Bank, N.A.,
  Authenticating Agent

By ________________________
   Authorized Officer


<PAGE>

                                 EXHIBIT II-B-2
                   [FORM OF FACE OF CLASS II-B-2 CERTIFICATE]

THIS CERTIFICATE IS SUBORDINATED IN RIGHT OF PAYMENT TO THE GROUP II-A
CERTIFICATES AND THE CLASS II-B-1 CERTIFICATES AS DESCRIBED IN THE AGREEMENT
REFERRED TO HEREIN.

[UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE
DEPOSITORY TRUST COMPANY TO THE DEPOSITOR OR ITS AGENT FOR REGISTRATION OF
TRANSFER, EXCHANGE OR PAYMENT, AND ANY CERTIFICATE ISSUED IS REGISTERED IN THE
NAME OF CEDE & CO. OR SUCH OTHER NAME AS REQUESTED BY AN AUTHORIZED
REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY AND ANY PAYMENT IS MADE TO CEDE &
CO., ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO
ANY PERSON IS WRONGFUL SINCE THE REGISTERED OWNER HEREOF, CEDE & CO., HAS AN
INTEREST HEREIN.]

                        MORTGAGE PASS-THROUGH CERTIFICATE
                           SERIES 2006-4, CLASS II-B-2

 evidencing an interest in a pool of fixed interest rate, monthly pay, fully
amortizing, first lien, one- to four-family residential mortgage loans sold by

                   WELLS FARGO ASSET SECURITIES CORPORATION
             (Not an interest in or obligation of the Depositor)

            THIS CERTIFICATE DOES NOT EVIDENCE AN OBLIGATION OF, OR AN INTEREST
IN, THE DEPOSITOR, THE MASTER SERVICER, THE TRUSTEE OR ANY OF THEIR AFFILIATES,
AND IS NOT INSURED OR GUARANTEED BY THE DEPOSITOR, THE MASTER SERVICER, THE
TRUSTEE OR ANY OF THEIR AFFILIATES, OR BY ANY GOVERNMENT AGENCY OR PRIVATE
INSURER.

            DISTRIBUTIONS IN REDUCTION OF THE PRINCIPAL BALANCE OF THIS
CERTIFICATE WILL BE MADE IN THE MANNER DESCRIBED IN THE AGREEMENT. ACCORDINGLY,
THE OUTSTANDING PRINCIPAL BALANCE OF THIS CERTIFICATE AT ANY TIME MAY BE LESS
THAN THE INITIAL PRINCIPAL BALANCE REPRESENTED HEREBY.

Certificate No.                        Cut-Off Date:  March 1, 2006

CUSIP No.:  94983B BA 6                First Distribution Date: April 25, 2006

ISIN No.: US94983BBA61                 Denomination:  $

Percentage Interest evidenced          Final Scheduled Maturity Date:  April 25,
by this Certificate: %                 2036


      THIS CERTIFIES THAT ____________________________ is the registered owner
of the Percentage Interest evidenced by this Certificate in monthly
distributions to the Holders of the Class II-B-2 Certificates with respect to a
Trust Estate consisting of a pool of fixed interest rate, monthly pay, fully
amortizing, first lien, one- to four-family residential mortgage loans, other
than the Fixed Retained Yield, if any, with respect thereto, consisting of two
loan groups (the "Group I Mortgage Loans" and "Group II Mortgage Loans,"
respectively), formed by Wells Fargo Asset Securities Corporation (hereinafter
called the "Depositor," which term includes any successor entity under the
Agreement referred to below). The Trust Estate was created pursuant to a Pooling
and Servicing Agreement dated as of March 30, 2006 (the "Agreement") among the
Depositor, Wells Fargo Bank, N.A., as master servicer (the "Master Servicer")
and U.S. Bank National Association, as trustee (the "Trustee"), a summary of
certain of the pertinent provisions of which is set forth hereinafter. To the
extent not defined herein, the capitalized terms used herein have the meanings
ascribed to such terms in the Agreement. This Certificate is issued under and is
subject to the terms, provisions and conditions of the Agreement, to which
Agreement the Holder of this Certificate by virtue of the acceptance hereof
assents and by which such Holder is bound.

      Pursuant to the terms of the Agreement, a distribution will be made on the
25th day of each month or, if such 25th day is not a Business Day, the Business
Day immediately following (the "Distribution Date"), commencing on the first
Distribution Date specified above, to the Person in whose name this Certificate
is registered at the close of business on the Record Date, in an amount equal to
the product of the Percentage Interest evidenced by this Certificate and,
subject to the prior rights of the Group II-A Certificates and each Class of
Class B Certificates of the related Group bearing a lower numerical designation
as specified in the Agreement, any Class II-B-2 Distribution Amount required to
be distributed to Holders of the Class II-B-2 Certificates on such Distribution
Date, subject to adjustment, in certain events, as specified in the Agreement.
The pass-through rate on the Class II-B-2 Certificates applicable to each
Distribution Date will be 5.750% per annum. The amount of interest which accrues
on this Certificate in any month will be subject to reduction with respect to
any Non-Supported Interest Shortfall and any Relief Act Shortfall allocated to
the Class II-B-2 Certificates, as described in the Agreement.

      Distributions on this Certificate will be made by the Paying Agent by
check mailed to the address of the Person entitled thereto, as such name and
address shall appear on the Certificate Register, unless such Person is entitled
to receive payments by wire transfer in immediately available funds in
accordance with the Agreement and such Person has notified the Paying Agent
pursuant to the Agreement that such payments are to be made by wire transfer of
immediately available funds. Notwithstanding the above, the final distribution
in reduction of the Principal Balance of this Certificate will be made after due
notice of the pendency of such distribution and only upon presentation and
surrender of this Certificate at the office or agency of the Paying Agent
specified for that purpose in the notice of final distribution.

      Reference is hereby made to the further provisions of this Certificate set
forth on the reverse hereof, which further provisions shall for all purposes
have the same effect as if set forth at this place.

      This Certificate constitutes a "regular interest" in a "real estate
mortgage investment conduit" as those terms are defined in Section 860G(a)(1)
and Section 860D, respectively, of the Internal Revenue Code of 1986, as
amended.

      Unless this Certificate has been countersigned by an authorized officer of
the Authenticating Agent, by manual signature, this Certificate shall not be
entitled to any benefit under the Agreement or be valid for any purpose.


<PAGE>

            IN WITNESS WHEREOF, the Paying Agent has caused this Certificate to
be duly executed as of the date set forth below.

Dated:

                                       Wells Fargo Bank, N.A.,
                                            Paying Agent

                                       By____________________________
                                            Authorized Officer

Countersigned:

Wells Fargo Bank, N.A.,
  Authenticating Agent

By ________________________
   Authorized Officer


<PAGE>

                                 EXHIBIT II-B-3
                   [FORM OF FACE OF CLASS II-B-3 CERTIFICATE]

THIS CERTIFICATE IS SUBORDINATED IN RIGHT OF PAYMENT TO THE GROUP II-A
CERTIFICATES, THE CLASS II-B-1 CERTIFICATES AND THE CLASS II-B-2 CERTIFICATES AS
DESCRIBED IN THE AGREEMENT REFERRED TO HEREIN.

[UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE
DEPOSITORY TRUST COMPANY TO THE DEPOSITOR OR ITS AGENT FOR REGISTRATION OF
TRANSFER, EXCHANGE OR PAYMENT, AND ANY CERTIFICATE ISSUED IS REGISTERED IN THE
NAME OF CEDE & CO. OR SUCH OTHER NAME AS REQUESTED BY AN AUTHORIZED
REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY AND ANY PAYMENT IS MADE TO CEDE &
CO., ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO
ANY PERSON IS WRONGFUL SINCE THE REGISTERED OWNER HEREOF, CEDE & CO., HAS AN
INTEREST HEREIN.]

                        MORTGAGE PASS-THROUGH CERTIFICATE
                           SERIES 2006-4, CLASS II-B-3

 evidencing an interest in a pool of fixed interest rate, monthly pay, fully
amortizing, first lien, one- to four-family residential mortgage loans sold by

                   WELLS FARGO ASSET SECURITIES CORPORATION
             (Not an interest in or obligation of the Depositor)

            THIS CERTIFICATE DOES NOT EVIDENCE AN OBLIGATION OF, OR AN INTEREST
IN, THE DEPOSITOR, THE MASTER SERVICER, THE TRUSTEE OR ANY OF THEIR AFFILIATES,
AND IS NOT INSURED OR GUARANTEED BY THE DEPOSITOR, THE MASTER SERVICER, THE
TRUSTEE OR ANY OF THEIR AFFILIATES, OR BY ANY GOVERNMENT AGENCY OR PRIVATE
INSURER.

            DISTRIBUTIONS IN REDUCTION OF THE PRINCIPAL BALANCE OF THIS
CERTIFICATE WILL BE MADE IN THE MANNER DESCRIBED IN THE AGREEMENT. ACCORDINGLY,
THE OUTSTANDING PRINCIPAL BALANCE OF THIS CERTIFICATE AT ANY TIME MAY BE LESS
THAN THE INITIAL PRINCIPAL BALANCE REPRESENTED HEREBY.

Certificate No.                        Cut-Off Date:  March 1, 2006

CUSIP No.:  94983B BB 4                First Distribution Date: April 25, 2006

ISIN No.: US94983BBB45                 Denomination:  $

Percentage Interest evidenced          Final Scheduled Maturity Date:  April 25,
by this Certificate: %                 2036


      THIS CERTIFIES THAT _______________________________ is the registered
owner of the Percentage Interest evidenced by this Certificate in monthly
distributions to the Holders of the Class II-B-3 Certificates with respect to a
Trust Estate consisting of a pool of fixed interest rate, monthly pay, fully
amortizing, first lien, one- to four-family residential mortgage loans, other
than the Fixed Retained Yield, if any, with respect thereto, consisting of two
loan groups (the "Group I Mortgage Loans" and "Group II Mortgage Loans,"
respectively), formed by Wells Fargo Asset Securities Corporation (hereinafter
called the "Depositor," which term includes any successor entity under the
Agreement referred to below). The Trust Estate was created pursuant to a Pooling
and Servicing Agreement dated as of March 30, 2006 (the "Agreement") among the
Depositor, Wells Fargo Bank, N.A., as master servicer (the "Master Servicer")
and U.S. Bank National Association, as trustee (the "Trustee"), a summary of
certain of the pertinent provisions of which is set forth hereinafter. To the
extent not defined herein, the capitalized terms used herein have the meanings
ascribed to such terms in the Agreement. This Certificate is issued under and is
subject to the terms, provisions and conditions of the Agreement, to which
Agreement the Holder of this Certificate by virtue of the acceptance hereof
assents and by which such Holder is bound.

      Pursuant to the terms of the Agreement, a distribution will be made on the
25th day of each month or, if such 25th day is not a Business Day, the Business
Day immediately following (the "Distribution Date"), commencing on the first
Distribution Date specified above, to the Person in whose name this Certificate
is registered at the close of business on the Record Date, in an amount equal to
the product of the Percentage Interest evidenced by this Certificate and,
subject to the prior rights of the Group II-A Certificates and each Class of
Class B Certificates of the related Group bearing a lower numerical designation
as specified in the Agreement, any Class II-B-3 Distribution Amount required to
be distributed to Holders of the Class II-B-3 Certificates on such Distribution
Date, subject to adjustment, in certain events, as specified in the Agreement.
The pass-through rate on the Class II-B-3 Certificates applicable to each
Distribution Date will be 5.750% per annum. The amount of interest which accrues
on this Certificate in any month will be subject to reduction with respect to
any Non-Supported Interest Shortfall and any Relief Act Shortfall allocated to
the Class II-B-3 Certificates, as described in the Agreement.

      Distributions on this Certificate will be made by the Paying Agent by
check mailed to the address of the Person entitled thereto, as such name and
address shall appear on the Certificate Register, unless such Person is entitled
to receive payments by wire transfer in immediately available funds in
accordance with the Agreement and such Person has notified the Paying Agent
pursuant to the Agreement that such payments are to be made by wire transfer of
immediately available funds. Notwithstanding the above, the final distribution
in reduction of the Principal Balance of this Certificate will be made after due
notice of the pendency of such distribution and only upon presentation and
surrender of this Certificate at the office or agency of the Paying Agent
specified for that purpose in the notice of final distribution.

      Reference is hereby made to the further provisions of this Certificate set
forth on the reverse hereof, which further provisions shall for all purposes
have the same effect as if set forth at this place.

      This Certificate constitutes a "regular interest" in a "real estate
mortgage investment conduit" as those terms are defined in Section 860G(a)(1)
and Section 860D, respectively, of the Internal Revenue Code of 1986, as
amended.

      Unless this Certificate has been countersigned by an authorized officer of
the Authenticating Agent, by manual signature, this Certificate shall not be
entitled to any benefit under the Agreement or be valid for any purpose.


<PAGE>

            IN WITNESS WHEREOF, the Paying Agent has caused this Certificate to
be duly executed as of the date set forth below.

Dated:

                                       Wells Fargo Bank, N.A.,
                                            Paying Agent

                                       By____________________________
                                            Authorized Officer

Countersigned:

Wells Fargo Bank, N.A.,
  Authenticating Agent

By ________________________
   Authorized Officer


<PAGE>

                                EXHIBIT II-B-4
                  [FORM OF FACE OF CLASS II-B-4 CERTIFICATE]

THIS CERTIFICATE IS SUBORDINATED IN RIGHT OF PAYMENT TO THE GROUP II-A
CERTIFICATES, THE CLASS II-B-1 CERTIFICATES, THE CLASS II-B-2 CERTIFICATES AND
THE CLASS II-B-3 CERTIFICATES AS DESCRIBED IN THE AGREEMENT REFERRED TO HEREIN.

THIS CERTIFICATE HAS NOT BEEN AND WILL NOT BE REGISTERED UNDER THE SECURITIES
ACT OF 1933, AS AMENDED, OR THE SECURITIES LAWS OF ANY STATE AND MAY NOT BE
RESOLD OR TRANSFERRED UNLESS IT IS REGISTERED PURSUANT TO SUCH ACT AND LAWS OR
IS SOLD OR TRANSFERRED IN TRANSACTIONS WHICH ARE EXEMPT FROM REGISTRATION UNDER
SUCH ACT AND UNDER APPLICABLE STATE LAW AND IS TRANSFERRED IN ACCORDANCE WITH
THE PROVISIONS OF SECTION 5.02 OF THE AGREEMENT REFERRED TO HEREIN.

EXCEPT AS PROVIDED IN SECTION 5.02(C) OF THE AGREEMENT REFERRED TO HEREIN, THIS
CERTIFICATE MAY NOT BE PURCHASED BY OR TRANSFERRED TO ANY PERSON THAT HAS NOT
DELIVERED A REPRESENTATION LETTER STATING EITHER (A) THAT THE TRANSFEREE IS NOT
AN EMPLOYEE BENEFIT PLAN OR OTHER RETIREMENT ARRANGEMENT SUBJECT TO TITLE I OF
THE EMPLOYEE RETIREMENT INCOME SECURITY ACT OF 1974, AS AMENDED ("ERISA"), OR
SECTION 4975 OF THE INTERNAL REVENUE CODE OF 1986, AS AMENDED (THE "CODE"), OR A
GOVERNMENTAL PLAN, AS DEFINED IN SECTION 3(32) OF ERISA, SUBJECT TO ANY FEDERAL,
STATE OR LOCAL LAW WHICH IS, TO A MATERIAL EXTENT, SIMILAR TO THE FOREGOING
PROVISIONS OF ERISA OR THE CODE (COLLECTIVELY, A "PLAN"), AND IS NOT ACTING ON
BEHALF OF OR INVESTING THE ASSETS OF A PLAN OR (B) SUBJECT TO CERTAIN CONDITIONS
SET FORTH IN THE AGREEMENT, THAT THE SOURCE OF FUNDS USED TO PURCHASE THIS
CERTIFICATE IS AN "INSURANCE COMPANY GENERAL ACCOUNT."


                        MORTGAGE PASS-THROUGH CERTIFICATE
                           SERIES 2006-4, CLASS II-B-4

 evidencing an interest in a pool of fixed interest rate, monthly pay, fully
amortizing, first lien, one- to four-family residential mortgage loans sold by

                   WELLS FARGO ASSET SECURITIES CORPORATION
             (Not an interest in or obligation of the Depositor)

            THIS CERTIFICATE DOES NOT EVIDENCE AN OBLIGATION OF, OR AN INTEREST
IN, THE DEPOSITOR, THE MASTER SERVICER, THE TRUSTEE OR ANY OF THEIR AFFILIATES,
AND IS NOT INSURED OR GUARANTEED BY THE DEPOSITOR, THE MASTER SERVICER, THE
TRUSTEE OR ANY OF THEIR AFFILIATES, OR BY ANY GOVERNMENT AGENCY OR PRIVATE
INSURER.

            DISTRIBUTIONS IN REDUCTION OF THE PRINCIPAL BALANCE OF THIS
CERTIFICATE WILL BE MADE IN THE MANNER DESCRIBED IN THE AGREEMENT. ACCORDINGLY,
THE OUTSTANDING PRINCIPAL BALANCE OF THIS CERTIFICATE AT ANY TIME MAY BE LESS
THAN THE INITIAL PRINCIPAL BALANCE REPRESENTED HEREBY.

Certificate No.                        Cut-Off Date:  March 1, 2006

CUSIP No.: 94983B BF 5                 First Distribution Date: April 25, 2006

ISIN No.: US94983BBF58                 Denomination:  $

Percentage Interest evidenced          Final Scheduled Maturity Date:  April 25,
by this Certificate: %                 2036


      THIS CERTIFIES THAT ____________________________ is the registered owner
of the Percentage Interest evidenced by this Certificate in monthly
distributions to the Holders of the Class II-B-4 Certificates with respect to a
Trust Estate consisting of a pool of fixed interest rate, monthly pay, fully
amortizing, first lien, one- to four-family residential mortgage loans, other
than the Fixed Retained Yield, if any, with respect thereto, consisting of two
loan groups (the "Group I Mortgage Loans" and "Group II Mortgage Loans,"
respectively), formed by Wells Fargo Asset Securities Corporation (hereinafter
called the "Depositor," which term includes any successor entity under the
Agreement referred to below). The Trust Estate was created pursuant to a Pooling
and Servicing Agreement dated as of March 30, 2006 (the "Agreement") among the
Depositor, Wells Fargo Bank, N.A., as master servicer (the "Master Servicer")
and U.S. Bank National Association, as trustee (the "Trustee"), a summary of
certain of the pertinent provisions of which is set forth hereinafter. To the
extent not defined herein, the capitalized terms used herein have the meanings
ascribed to such terms in the Agreement. This Certificate is issued under and is
subject to the terms, provisions and conditions of the Agreement, to which
Agreement the Holder of this Certificate by virtue of the acceptance hereof
assents and by which such Holder is bound.

      Pursuant to the terms of the Agreement, a distribution will be made on the
25th day of each month or, if such 25th day is not a Business Day, the Business
Day immediately following (the "Distribution Date"), commencing on the first
Distribution Date specified above, to the Person in whose name this Certificate
is registered at the close of business on the Record Date, in an amount equal to
the product of the Percentage Interest evidenced by this Certificate and,
subject to the prior rights of the Group II-A Certificates and each Class of
Class B Certificates of the related Group bearing a lower numerical designation
as specified in the Agreement, any Class II-B-4 Distribution Amount required to
be distributed to Holders of the Class II-B-4 Certificates on such Distribution
Date, subject to adjustment, in certain events, as specified in the Agreement.
The pass-through rate on the Class II-B-4 Certificates applicable to each
Distribution Date will be 5.750% per annum. The amount of interest which accrues
on this Certificate in any month will be subject to reduction with respect to
any Non-Supported Interest Shortfall and any Relief Act Shortfall allocated to
the Class II-B-4 Certificates, as described in the Agreement.

      Distributions on this Certificate will be made by the Paying Agent by
check mailed to the address of the Person entitled thereto, as such name and
address shall appear on the Certificate Register, unless such Person is entitled
to receive payments by wire transfer in immediately available funds in
accordance with the Agreement and such Person has notified the Paying Agent
pursuant to the Agreement that such payments are to be made by wire transfer of
immediately available funds. Notwithstanding the above, the final distribution
in reduction of the Principal Balance of this Certificate will be made after due
notice of the pendency of such distribution and only upon presentation and
surrender of this Certificate at the office or agency of the Paying Agent
specified for that purpose in the notice of final distribution.

      No transfer of a Class II-B-4 Certificate will be made unless such
transfer is exempt from the registration requirements of the Securities Act of
1933, as amended, and any applicable state securities laws or is made in
accordance with said Act and laws. In the event that such a transfer is desired
to be made by the Holder hereof, (i) the transferee will be required to execute
an investment letter in the form described in the Agreement and (ii) if such
transfer is to be made within three years from the later of (a) the date of
initial issuance of the Certificates or (b) the last date on which the Depositor
or any affiliate thereof was a Holder of the Certificates proposed to be
transferred, and unless such transfer is made in reliance on Rule 144A of the
Securities Act of 1933, as amended, the Master Servicer or the Depositor may
require the Holder to deliver an opinion of counsel acceptable to and in form
and substance satisfactory to the Master Servicer and the Depositor that such
transfer is exempt (describing the applicable exemption and the basis therefor)
from or is being made pursuant to the registration requirements of the
Securities Act of 1933, as amended, and of any applicable statute of any state.
The Holder hereof desiring to effect such transfer shall, and does hereby agree
to, indemnify the Trustee, the Depositor, the Master Servicer, and any Paying
Agent against any liability that may result if the transfer is not so exempt or
is not made in accordance with such Federal and state laws. In connection with
any such transfer, the Master Servicer will also require (i) a representation
letter, in the form as described in the Agreement, stating either (a) that the
transferee is not a Plan and is not acting on behalf of a Plan or using the
assets of a Plan to effect such purchase or (b) subject to certain conditions
described in the Agreement, that the source of funds used to purchase this
Certificate is an "insurance company general account," or (ii) if such
transferee is a Plan, (a) an opinion of counsel acceptable to and in form and
substance satisfactory to the Master Servicer and the Depositor with respect to
certain matters and (b) such other documentation as the Depositor or the Master
Servicer may require, as described in the Agreement.

      Reference is hereby made to the further provisions of this Certificate set
forth on the reverse hereof, which further provisions shall for all purposes
have the same effect as if set forth at this place.

      This Certificate constitutes a "regular interest" in a "real estate
mortgage investment conduit" as those terms are defined in Section 860G(a)(1)
and Section 860D, respectively, of the Internal Revenue Code of 1986, as
amended.

      Unless this Certificate has been countersigned by an authorized officer of
the Authenticating Agent, by manual signature, this Certificate shall not be
entitled to any benefit under the Agreement or be valid for any purpose.


<PAGE>

            IN WITNESS WHEREOF, the Paying Agent has caused this Certificate to
be duly executed as of the date set forth below.

Dated:

                                       Wells Fargo Bank, N.A.,
                                            Paying Agent

                                       By____________________________
                                            Authorized Officer

Countersigned:

Wells Fargo Bank, N.A.,
  Authenticating Agent

By ________________________
   Authorized Officer


<PAGE>

                                EXHIBIT II-B-5
                  [FORM OF FACE OF CLASS II-B-5 CERTIFICATE]

THIS CERTIFICATE IS SUBORDINATED IN RIGHT OF PAYMENT TO THE GROUP II-A
CERTIFICATES, THE CLASS II-B-1 CERTIFICATES, THE CLASS II-B-2 CERTIFICATES, THE
CLASS II-B-3 CERTIFICATES AND THE CLASS II-B-4 CERTIFICATES AS DESCRIBED IN THE
AGREEMENT REFERRED TO HEREIN.

THIS CERTIFICATE HAS NOT BEEN AND WILL NOT BE REGISTERED UNDER THE SECURITIES
ACT OF 1933, AS AMENDED, OR THE SECURITIES LAWS OF ANY STATE AND MAY NOT BE
RESOLD OR TRANSFERRED UNLESS IT IS REGISTERED PURSUANT TO SUCH ACT AND LAWS OR
IS SOLD OR TRANSFERRED IN TRANSACTIONS WHICH ARE EXEMPT FROM REGISTRATION UNDER
SUCH ACT AND UNDER APPLICABLE STATE LAW AND IS TRANSFERRED IN ACCORDANCE WITH
THE PROVISIONS OF SECTION 5.02 OF THE AGREEMENT REFERRED TO HEREIN.

EXCEPT AS PROVIDED IN SECTION 5.02(C) OF THE AGREEMENT REFERRED TO HEREIN, THIS
CERTIFICATE MAY NOT BE PURCHASED BY OR TRANSFERRED TO ANY PERSON THAT HAS NOT
DELIVERED A REPRESENTATION LETTER STATING EITHER (A) THAT THE TRANSFEREE IS NOT
AN EMPLOYEE BENEFIT PLAN OR OTHER RETIREMENT ARRANGEMENT SUBJECT TO TITLE I OF
THE EMPLOYEE RETIREMENT INCOME SECURITY ACT OF 1974, AS AMENDED ("ERISA"), OR
SECTION 4975 OF THE INTERNAL REVENUE CODE OF 1986, AS AMENDED (THE "CODE"), OR A
GOVERNMENTAL PLAN, AS DEFINED IN SECTION 3(32) OF ERISA, SUBJECT TO ANY FEDERAL,
STATE OR LOCAL LAW WHICH IS, TO A MATERIAL EXTENT, SIMILAR TO THE FOREGOING
PROVISIONS OF ERISA OR THE CODE (COLLECTIVELY, A "PLAN"), AND IS NOT ACTING ON
BEHALF OF OR INVESTING THE ASSETS OF A PLAN OR (B) SUBJECT TO CERTAIN CONDITIONS
SET FORTH IN THE AGREEMENT, THAT THE SOURCE OF FUNDS USED TO PURCHASE THIS
CERTIFICATE IS AN "INSURANCE COMPANY GENERAL ACCOUNT."


                        MORTGAGE PASS-THROUGH CERTIFICATE
                           SERIES 2006-4, CLASS II-B-5

 evidencing an interest in a pool of fixed interest rate, monthly pay, fully
amortizing, first lien, one- to four-family residential mortgage loans sold by

                   WELLS FARGO ASSET SECURITIES CORPORATION
             (Not an interest in or obligation of the Depositor)

            THIS CERTIFICATE DOES NOT EVIDENCE AN OBLIGATION OF, OR AN INTEREST
IN, THE DEPOSITOR, THE MASTER SERVICER, THE TRUSTEE OR ANY OF THEIR AFFILIATES,
AND IS NOT INSURED OR GUARANTEED BY THE DEPOSITOR, THE MASTER SERVICER, THE
TRUSTEE OR ANY OF THEIR AFFILIATES, OR BY ANY GOVERNMENT AGENCY OR PRIVATE
INSURER.

            DISTRIBUTIONS IN REDUCTION OF THE PRINCIPAL BALANCE OF THIS
CERTIFICATE WILL BE MADE IN THE MANNER DESCRIBED IN THE AGREEMENT. ACCORDINGLY,
THE OUTSTANDING PRINCIPAL BALANCE OF THIS CERTIFICATE AT ANY TIME MAY BE LESS
THAN THE INITIAL PRINCIPAL BALANCE REPRESENTED HEREBY.

Certificate No.                        Cut-Off Date:  March 1, 2006

CUSIP No.: 94983B BG 3                 First Distribution Date: April 25, 2006

ISIN No.: US94983BBG32                 Denomination:  $

Percentage Interest evidenced          Final Scheduled Maturity Date:  April 25,
by this Certificate: %                 2036


      THIS CERTIFIES THAT ____________________________ is the registered owner
of the Percentage Interest evidenced by this Certificate in monthly
distributions to the Holders of the Class II-B-5 Certificates with respect to a
Trust Estate consisting of a pool of fixed interest rate, monthly pay, fully
amortizing, first lien, one- to four-family residential mortgage loans, other
than the Fixed Retained Yield, if any, with respect thereto, consisting of two
loan groups (the "Group I Mortgage Loans" and "Group II Mortgage Loans,"
respectively), formed by Wells Fargo Asset Securities Corporation (hereinafter
called the "Depositor," which term includes any successor entity under the
Agreement referred to below). The Trust Estate was created pursuant to a Pooling
and Servicing Agreement dated as of March 30, 2006 (the "Agreement") among the
Depositor, Wells Fargo Bank, N.A., as master servicer (the "Master Servicer")
and U.S. Bank National Association, as trustee (the "Trustee"), a summary of
certain of the pertinent provisions of which is set forth hereinafter. To the
extent not defined herein, the capitalized terms used herein have the meanings
ascribed to such terms in the Agreement. This Certificate is issued under and is
subject to the terms, provisions and conditions of the Agreement, to which
Agreement the Holder of this Certificate by virtue of the acceptance hereof
assents and by which such Holder is bound.

      Pursuant to the terms of the Agreement, a distribution will be made on the
25th day of each month or, if such 25th day is not a Business Day, the Business
Day immediately following (the "Distribution Date"), commencing on the first
Distribution Date specified above, to the Person in whose name this Certificate
is registered at the close of business on the Record Date, in an amount equal to
the product of the Percentage Interest evidenced by this Certificate and,
subject to the prior rights of the Group II-A Certificates and each Class of
Class B Certificates of the related Group bearing a lower numerical designation
as specified in the Agreement, any Class II-B-5 Distribution Amount required to
be distributed to Holders of the Class II-B-5 Certificates on such Distribution
Date, subject to adjustment, in certain events, as specified in the Agreement.
The pass-through rate on the Class II-B-5 Certificates applicable to each
Distribution Date will be 5.750% per annum. The amount of interest which accrues
on this Certificate in any month will be subject to reduction with respect to
any Non-Supported Interest Shortfall and any Relief Act Shortfall allocated to
the Class II-B-5 Certificates, as described in the Agreement.

      Distributions on this Certificate will be made by the Paying Agent by
check mailed to the address of the Person entitled thereto, as such name and
address shall appear on the Certificate Register, unless such Person is entitled
to receive payments by wire transfer in immediately available funds in
accordance with the Agreement and such Person has notified the Paying Agent
pursuant to the Agreement that such payments are to be made by wire transfer of
immediately available funds. Notwithstanding the above, the final distribution
in reduction of the Principal Balance of this Certificate will be made after due
notice of the pendency of such distribution and only upon presentation and
surrender of this Certificate at the office or agency of the Paying Agent
specified for that purpose in the notice of final distribution.

      No transfer of a Class II-B-5 Certificate will be made unless such
transfer is exempt from the registration requirements of the Securities Act of
1933, as amended, and any applicable state securities laws or is made in
accordance with said Act and laws. In the event that such a transfer is desired
to be made by the Holder hereof, (i) the transferee will be required to execute
an investment letter in the form described in the Agreement and (ii) if such
transfer is to be made within three years from the later of (a) the date of
initial issuance of the Certificates or (b) the last date on which the Depositor
or any affiliate thereof was a Holder of the Certificates proposed to be
transferred, and unless such transfer is made in reliance on Rule 144A of the
Securities Act of 1933, as amended, the Master Servicer or the Depositor may
require the Holder to deliver an opinion of counsel acceptable to and in form
and substance satisfactory to the Master Servicer and the Depositor that such
transfer is exempt (describing the applicable exemption and the basis therefor)
from or is being made pursuant to the registration requirements of the
Securities Act of 1933, as amended, and of any applicable statute of any state.
The Holder hereof desiring to effect such transfer shall, and does hereby agree
to, indemnify the Trustee, the Depositor, the Master Servicer, and any Paying
Agent against any liability that may result if the transfer is not so exempt or
is not made in accordance with such Federal and state laws. In connection with
any such transfer, the Master Servicer will also require (i) a representation
letter, in the form as described in the Agreement, stating either (a) that the
transferee is not a Plan and is not acting on behalf of a Plan or using the
assets of a Plan to effect such purchase or (b) subject to certain conditions
described in the Agreement, that the source of funds used to purchase this
Certificate is an "insurance company general account," or (ii) if such
transferee is a Plan, (a) an opinion of counsel acceptable to and in form and
substance satisfactory to the Master Servicer and the Depositor with respect to
certain matters and (b) such other documentation as the Depositor or the Master
Servicer may require, as described in the Agreement.

      Reference is hereby made to the further provisions of this Certificate set
forth on the reverse hereof, which further provisions shall for all purposes
have the same effect as if set forth at this place.

      This Certificate constitutes a "regular interest" in a "real estate
mortgage investment conduit" as those terms are defined in Section 860G(a)(1)
and Section 860D, respectively, of the Internal Revenue Code of 1986, as
amended.

      Unless this Certificate has been countersigned by an authorized officer of
the Authenticating Agent, by manual signature, this Certificate shall not be
entitled to any benefit under the Agreement or be valid for any purpose.


<PAGE>

            IN WITNESS WHEREOF, the Paying Agent has caused this Certificate to
be duly executed as of the date set forth below.

Dated:

                                       Wells Fargo Bank, N.A.,
                                            Paying Agent

                                       By____________________________
                                            Authorized Officer

Countersigned:

Wells Fargo Bank, N.A.,
  Authenticating Agent

By ________________________
   Authorized Officer


<PAGE>

                                 EXHIBIT II-B-6
                   [FORM OF FACE OF CLASS II-B-6 CERTIFICATE]

THIS CERTIFICATE IS SUBORDINATED IN RIGHT OF PAYMENT TO THE GROUP II-A
CERTIFICATES, THE CLASS II-B-1 CERTIFICATES, THE CLASS II-B-2 CERTIFICATES, THE
CLASS II-B-3 CERTIFICATES, THE CLASS II-B-4 CERTIFICATES AND THE CLASS II-B-5
CERTIFICATES AS DESCRIBED IN THE AGREEMENT REFERRED TO HEREIN.

THIS CERTIFICATE HAS NOT BEEN AND WILL NOT BE REGISTERED UNDER THE SECURITIES
ACT OF 1933, AS AMENDED, OR THE SECURITIES LAWS OF ANY STATE AND MAY NOT BE
RESOLD OR TRANSFERRED UNLESS IT IS REGISTERED PURSUANT TO SUCH ACT AND LAWS OR
IS SOLD OR TRANSFERRED IN TRANSACTIONS WHICH ARE EXEMPT FROM REGISTRATION UNDER
SUCH ACT AND UNDER APPLICABLE STATE LAW AND IS TRANSFERRED IN ACCORDANCE WITH
THE PROVISIONS OF SECTION 5.02 OF THE AGREEMENT REFERRED TO HEREIN.

EXCEPT AS PROVIDED IN SECTION 5.02(C) OF THE AGREEMENT REFERRED TO HEREIN, THIS
CERTIFICATE MAY NOT BE PURCHASED BY OR TRANSFERRED TO ANY PERSON THAT HAS NOT
DELIVERED A REPRESENTATION LETTER STATING EITHER (A) THAT THE TRANSFEREE IS NOT
AN EMPLOYEE BENEFIT PLAN OR OTHER RETIREMENT ARRANGEMENT SUBJECT TO TITLE I OF
THE EMPLOYEE RETIREMENT INCOME SECURITY ACT OF 1974, AS AMENDED ("ERISA"), OR
SECTION 4975 OF THE INTERNAL REVENUE CODE OF 1986, AS AMENDED (THE "CODE"), OR A
GOVERNMENTAL PLAN, AS DEFINED IN SECTION 3(32) OF ERISA, SUBJECT TO ANY FEDERAL,
STATE OR LOCAL LAW WHICH IS, TO A MATERIAL EXTENT, SIMILAR TO THE FOREGOING
PROVISIONS OF ERISA OR THE CODE (COLLECTIVELY, A "PLAN"), AND IS NOT ACTING ON
BEHALF OF OR INVESTING THE ASSETS OF A PLAN OR (B) SUBJECT TO CERTAIN CONDITIONS
SET FORTH IN THE AGREEMENT, THAT THE SOURCE OF FUNDS USED TO PURCHASE THIS
CERTIFICATE IS AN "INSURANCE COMPANY GENERAL ACCOUNT."


                        MORTGAGE PASS-THROUGH CERTIFICATE
                           SERIES 2006-4, CLASS II-B-6

 evidencing an interest in a pool of fixed interest rate, monthly pay, fully
amortizing, first lien, one- to four-family residential mortgage loans sold by

                   WELLS FARGO ASSET SECURITIES CORPORATION
             (Not an interest in or obligation of the Depositor)

            THIS CERTIFICATE DOES NOT EVIDENCE AN OBLIGATION OF, OR AN INTEREST
IN, THE DEPOSITOR, THE MASTER SERVICER, THE TRUSTEE OR ANY OF THEIR AFFILIATES,
AND IS NOT INSURED OR GUARANTEED BY THE DEPOSITOR, THE MASTER SERVICER, THE
TRUSTEE OR ANY OF THEIR AFFILIATES, OR BY ANY GOVERNMENT AGENCY OR PRIVATE
INSURER.

            DISTRIBUTIONS IN REDUCTION OF THE PRINCIPAL BALANCE OF THIS
CERTIFICATE WILL BE MADE IN THE MANNER DESCRIBED IN THE AGREEMENT. ACCORDINGLY,
THE OUTSTANDING PRINCIPAL BALANCE OF THIS CERTIFICATE AT ANY TIME MAY BE LESS
THAN THE INITIAL PRINCIPAL BALANCE REPRESENTED HEREBY.

Certificate No.                        Cut-Off Date:  March 1, 2006

CUSIP No.: 94983B BH 1                 First Distribution Date: April 25, 2006

ISIN No.: US94983BBH15                 Denomination:  $

Percentage Interest evidenced          Final Scheduled Maturity Date:  April 25,
by this Certificate: %                 2036


      THIS CERTIFIES THAT ____________________________ is the registered owner
of the Percentage Interest evidenced by this Certificate in monthly
distributions to the Holders of the Class II-B-6 Certificates with respect to a
Trust Estate consisting of a pool of fixed interest rate, monthly pay, fully
amortizing, first lien, one- to four-family residential mortgage loans, other
than the Fixed Retained Yield, if any, with respect thereto, consisting of two
loan groups (the "Group I Mortgage Loans" and "Group II Mortgage Loans,"
respectively), formed by Wells Fargo Asset Securities Corporation (hereinafter
called the "Depositor," which term includes any successor entity under the
Agreement referred to below). The Trust Estate was created pursuant to a Pooling
and Servicing Agreement dated as of March 30, 2006 (the "Agreement") among the
Depositor, Wells Fargo Bank, N.A., as master servicer (the "Master Servicer")
and U.S. Bank National Association, as trustee (the "Trustee"), a summary of
certain of the pertinent provisions of which is set forth hereinafter. To the
extent not defined herein, the capitalized terms used herein have the meanings
ascribed to such terms in the Agreement. This Certificate is issued under and is
subject to the terms, provisions and conditions of the Agreement, to which
Agreement the Holder of this Certificate by virtue of the acceptance hereof
assents and by which such Holder is bound.

      Pursuant to the terms of the Agreement, a distribution will be made on the
25th day of each month or, if such 25th day is not a Business Day, the Business
Day immediately following (the "Distribution Date"), commencing on the first
Distribution Date specified above, to the Person in whose name this Certificate
is registered at the close of business on the Record Date, in an amount equal to
the product of the Percentage Interest evidenced by this Certificate and,
subject to the prior rights of the Group II-A Certificates and each Class of
Class B Certificates of the related Group bearing a lower numerical designation
as specified in the Agreement, any Class II-B-6 Distribution Amount required to
be distributed to Holders of the Class II-B-6 Certificates on such Distribution
Date, subject to adjustment, in certain events, as specified in the Agreement.
The pass-through rate on the Class II-B-6 Certificates applicable to each
Distribution Date will be 5.750% per annum. The amount of interest which accrues
on this Certificate in any month will be subject to reduction with respect to
any Non-Supported Interest Shortfall and any Relief Act Shortfall allocated to
the Class II-B-6 Certificates, as described in the Agreement.

      Distributions on this Certificate will be made by the Paying Agent by
check mailed to the address of the Person entitled thereto, as such name and
address shall appear on the Certificate Register, unless such Person is entitled
to receive payments by wire transfer in immediately available funds in
accordance with the Agreement and such Person has notified the Paying Agent
pursuant to the Agreement that such payments are to be made by wire transfer of
immediately available funds. Notwithstanding the above, the final distribution
in reduction of the Principal Balance of this Certificate will be made after due
notice of the pendency of such distribution and only upon presentation and
surrender of this Certificate at the office or agency of the Paying Agent
specified for that purpose in the notice of final distribution.

      No transfer of a Class II-B-6 Certificate will be made unless such
transfer is exempt from the registration requirements of the Securities Act of
1933, as amended, and any applicable state securities laws or is made in
accordance with said Act and laws. In the event that such a transfer is desired
to be made by the Holder hereof, (i) the transferee will be required to execute
an investment letter in the form described in the Agreement and (ii) if such
transfer is to be made within three years from the later of (a) the date of
initial issuance of the Certificates or (b) the last date on which the Depositor
or any affiliate thereof was a Holder of the Certificates proposed to be
transferred, and unless such transfer is made in reliance on Rule 144A of the
Securities Act of 1933, as amended, the Master Servicer or the Depositor may
require the Holder to deliver an opinion of counsel acceptable to and in form
and substance satisfactory to the Master Servicer and the Depositor that such
transfer is exempt (describing the applicable exemption and the basis therefor)
from or is being made pursuant to the registration requirements of the
Securities Act of 1933, as amended, and of any applicable statute of any state.
The Holder hereof desiring to effect such transfer shall, and does hereby agree
to, indemnify the Trustee, the Depositor, the Master Servicer, and any Paying
Agent against any liability that may result if the transfer is not so exempt or
is not made in accordance with such Federal and state laws. In connection with
any such transfer, the Master Servicer will also require (i) a representation
letter, in the form as described in the Agreement, stating either (a) that the
transferee is not a Plan and is not acting on behalf of a Plan or using the
assets of a Plan to effect such purchase or (b) subject to certain conditions
described in the Agreement, that the source of funds used to purchase this
Certificate is an "insurance company general account," or (ii) if such
transferee is a Plan, (a) an opinion of counsel acceptable to and in form and
substance satisfactory to the Master Servicer and the Depositor with respect to
certain matters and (b) such other documentation as the Depositor or the Master
Servicer may require, as described in the Agreement.

      Reference is hereby made to the further provisions of this Certificate set
forth on the reverse hereof, which further provisions shall for all purposes
have the same effect as if set forth at this place.

      This Certificate constitutes a "regular interest" in a "real estate
mortgage investment conduit" as those terms are defined in Section 860G(a)(1)
and Section 860D, respectively, of the Internal Revenue Code of 1986, as
amended.

      Unless this Certificate has been countersigned by an authorized officer of
the Authenticating Agent, by manual signature, this Certificate shall not be
entitled to any benefit under the Agreement or be valid for any purpose.


<PAGE>

            IN WITNESS WHEREOF, the Paying Agent has caused this Certificate to
be duly executed as of the date set forth below.

Dated:

                                       Wells Fargo Bank, N.A.,
                                            Paying Agent

                                       By____________________________
                                            Authorized Officer

Countersigned:

Wells Fargo Bank, N.A.,
  Authenticating Agent

By ________________________
   Authorized Officer


<PAGE>


                                    EXHIBIT C

                 [Form of Reverse of Series 2006-4 Certificates]

                   WELLS FARGO ASSET SECURITIES CORPORATION
                       MORTGAGE PASS-THROUGH CERTIFICATES
                                  SERIES 2006-4

      This Certificate is one of a duly authorized issue of Certificates issued
in several Classes designated as Mortgage Pass-Through Certificates of the
Series specified hereon (herein collectively called the "Certificates").

      The Certificates are limited in right of payment to certain collections
and recoveries respecting the Mortgage Loans, all as more specifically set forth
herein and in the Agreement. In the event funds are advanced with respect to any
Mortgage Loan by a Servicer, the Master Servicer or the Trustee, such advances
are reimbursable to such Servicer, the Master Servicer or the Trustee to the
extent provided in the Agreement, from related recoveries on such Mortgage Loan
or from other cash that would have been distributable to Certificateholders.

      As provided in the Agreement, withdrawals from the Certificate Account
created for the benefit of Certificateholders may be made by the Master Servicer
from time to time for purposes other than distributions to Certificateholders,
such purposes including reimbursement to a Servicer, the Master Servicer or the
Trustee, as applicable, of advances made by such Servicer, the Master Servicer
or the Trustee.

      The Agreement permits, with certain exceptions therein provided, the
amendment of the Agreement and the modification of the rights and obligations of
the Depositor, the Master Servicer and the Trustee and the rights of the
Certificateholders under the Agreement at any time by the Depositor, the Master
Servicer and the Trustee with the consent of the Holders of Certificates
evidencing in the aggregate not less than 66 2/3% of the Voting Interests of
each Class of Certificates affected thereby. Any such consent by the Holder of
this Certificate shall be conclusive and binding on such Holder and upon all
future holders of this Certificate and of any Certificate issued upon the
transfer hereof or in exchange hereof or in lieu hereof whether or not notation
of such consent is made upon the Certificate. The Agreement also permits the
amendment thereof in certain circumstances without the consent of the Holders of
any of the Certificates.

      As provided in the Agreement and subject to certain limitations therein
set forth, the transfer of this Certificate is registrable in the Certificate
Register upon surrender of this Certificate for registration of transfer at the
office or agency maintained by the Certificate Registrar, duly endorsed by, or
accompanied by an assignment in the form below or other written instrument of
transfer in form satisfactory to the Certificate Registrar, duly executed by the
Holder hereof or such Holder's attorney duly authorized in writing, and
thereupon one or more new Certificates of authorized Denominations evidencing
the same Class and aggregate Percentage Interest will be issued to the
designated transferee or transferees.

      The Certificates are issuable only as registered Certificates without
coupons in Classes and Denominations specified in the Agreement. As provided in
the Agreement and subject to certain limitations therein set forth, Certificates
are exchangeable for new Certificates of authorized Denominations evidencing the
same Class and aggregate Percentage Interest, as requested by the Holder
surrendering the same.

      No service charge will be made for any such registration of transfer or
exchange, but the Certificate Registrar may require payment of a sum sufficient
to cover any tax or other governmental charge payable in connection therewith.

      The Depositor, the Master Servicer, the Trustee, the Paying Agent and the
Certificate Registrar, and any agent of the Depositor, the Master Servicer, the
Trustee, the Paying Agent or the Certificate Registrar, may treat the Person in
whose name this Certificate is registered as the owner hereof for all purposes,
and neither the Depositor, the Master Servicer, the Trustee, the Certificate
Registrar nor any such agent shall be affected by notice to the contrary.

      The obligations created by the Agreement in respect of the Certificates
and the Trust Estate created thereby shall terminate upon the last action
required to be taken by the Paying Agent on the Final Distribution Date pursuant
to the Agreement following the earlier of (i) the payment or other liquidation
(or advance with respect thereto) of the last Mortgage Loan subject thereto or
the disposition of all property acquired upon foreclosure or deed in lieu of
foreclosure of any Mortgage Loan, and (ii) the purchase by the Depositor from
the Trust Estate of all remaining Mortgage Loans and all property acquired in
respect of such Mortgage Loans; provided, however, that the Trust Estate will in
no event continue beyond the expiration of 21 years from the death of the last
survivor of the descendants of Joseph P. Kennedy, the late ambassador of the
United States to the Court of St. James, living on the date of the Agreement.
The Agreement permits, but does not require, the Depositor to purchase all
remaining Mortgage Loans and all property acquired in respect of any Mortgage
Loan at a price determined as provided in the Agreement. The exercise of such
option will effect early retirement of the Certificates, the Depositor's right
to exercise such option being subject to the Pool Scheduled Principal Balance of
the Mortgage Loans as of the Distribution Date upon which the proceeds of such
repurchase are distributed being less than ten percent of the Cut-Off Date
Aggregate Principal Balance.


                                   ASSIGNMENT

 FOR VALUE RECEIVED, the undersigned hereby sell(s), assign(s) and transfer(s)
 unto
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
(Please print or typewrite name and address including postal zip code of
                                  assignee)

the beneficial interest evidenced by the within Mortgage Pass-Through
Certificate and hereby authorizes the transfer of registration of such interest
to assignee on the Certificate Register of the Trust Estate.

            I (We) further direct the Certificate Registrar to issue a new
Certificate of a like Denomination or Percentage Interest and Class, to the
above named assignee and deliver such Certificate to the following address:
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------

Social Security or other Identifying Number of Assignee:

Dated:

                                       -----------------------------------
                                          Signature by or on behalf of
                                          assignor

                                       -----------------------------------
                                          Signature Guaranteed


<PAGE>




                            DISTRIBUTION INSTRUCTIONS

            The assignee should include the following for purposes of
distribution:

            Distributions  shall be  made,  if the  assignee  is  eligible  to
receive  distributions  in immediately  available  funds,  by wire transfer or
otherwise,        in        immediately        available        funds       to
_________________________________________________________________    for   the
account  of  _______________________________________________   account  number
_____________,        or,       if       mailed       by       check,       to
_______________________________________________________.            Applicable
statements      should      be      mailed      to      ______________________
__________________________________.

            This  information  is  provided  by  ______________________,   the
assignee named above, or ___________________________________, as its agent.


<PAGE>

                                    EXHIBIT D

                                    RESERVED


<PAGE>


                                    EXHIBIT E


                               CUSTODIAL AGREEMENT

      THIS CUSTODIAL AGREEMENT (as amended and supplemented from time to time,
the "Agreement"), dated as of March 30, 2006, by and among U.S. BANK NATIONAL
ASSOCIATION, not individually, but solely as Trustee (including its successors
under the Pooling and Servicing Agreement defined below, the "Trustee"), WELLS
FARGO ASSET SECURITIES CORPORATION (together with any successor in interest, the
"Depositor"), WELLS FARGO BANK, N.A. (together with any successor in interest or
successor under the Pooling and Servicing Agreement referred to below, the
"Master Servicer") and WELLS FARGO BANK, N.A. (together with any successor in
interest or any successor appointed hereunder, the "Custodian").

                           W I T N E S S E T H T H A T

      WHEREAS, the Depositor, the Master Servicer, and the Trustee, have entered
into a Pooling and Servicing Agreement dated as of March 30, 2006 relating to
the issuance of Mortgage Pass-Through Certificates, Series 2006-4 (as amended
and supplemented from time to time, the "Pooling and Servicing Agreement"); and

      WHEREAS, the Custodian has agreed to act as agent for the Trustee for the
purposes of receiving and holding certain documents and other instruments
delivered by the Depositor under the Pooling and Servicing Agreement, all upon
the terms and conditions and subject to the limitations hereinafter set forth;

      NOW, THEREFORE, in consideration of the premises and the mutual covenants
and agreements hereinafter set forth, the Trustee, the Depositor, the Master
Servicer and the Custodian hereby agree as follows:

                                    ARTICLE I

                                   Definitions

      Capitalized terms used in this Agreement and not defined herein shall have
the meanings assigned in the Pooling and Servicing Agreement, unless otherwise
required by the context herein.

                                   ARTICLE II

                          Custody of Mortgage Documents

      Section 2.1. Custodian to Act as Agent; Acceptance of Custodial Files.
Subject to Section 2.3 hereof, the Custodian, as the duly appointed agent of the
Trustee for these purposes, declares that it holds and will hold the documents
delivered to it pursuant to Section 2.01 of the Pooling and Servicing Agreement
and any other documents constituting part of the Owner Mortgage Loan File or
Retained Mortgage Loan File received on or subsequent to the date hereof (the
"Custodial Files") as agent for the Trustee, in trust, for the use and benefit
of all present and future Certificateholders. The Depositor shall give written
notice to the Custodian within 10 business days of the occurrence of a Document
Transfer Event.

      Section 2.2. Recordation of Assignments. Unless an assignment of a
Mortgage is not required to be recorded in accordance with Section 2.01 of the
Pooling and Servicing Agreement, if any Custodial File includes one or more
assignments to the Trustee of Mortgage Notes that have not been recorded, each
such assignment shall be delivered by the Custodian to the Depositor for the
purpose of recording it in the appropriate public office for real property
records, and the Depositor, at no expense to the Custodian, shall promptly cause
to be recorded in the appropriate public office for real property records each
such assignment and, upon receipt thereof from such public office, shall return
each such assignment to the Custodian.

      Section 2.3. Review of Custodial Files. The Custodian agrees, for the
benefit of Certificateholders, to review, in accordance with the provisions of
Section 2.02 of the Pooling and Servicing Agreement, each Custodial File and to
provide the initial and final certifications in the forms of Exhibits N and O to
the Pooling and Servicing Agreement in accordance with the provisions thereof.
If in performing the review required by this Section 2.3 the Custodian finds any
document or documents constituting a part of a Custodial File to be missing or
defective, the Custodian shall follow the procedures specified in the Pooling
and Servicing Agreement.

      Section 2.4. Notification of Breaches of Representations and Warranties.
Upon discovery by the Custodian of a breach of any representation or warranty
made by the Depositor or the Master Servicer as set forth in the Pooling and
Servicing Agreement, the Custodian shall follow the procedures specified in the
Pooling and Servicing Agreement.

      Section 2.5. Custodian to Cooperate; Release of Custodial Files. Upon the
payment in full of any Mortgage Loan, or the receipt by the Master Servicer of a
notification that payment in full will be escrowed in a manner customary for
such purposes, the Master Servicer or applicable Servicer shall immediately
deliver to the Custodian two copies of a Request for Release or such request in
an electronic format acceptable to the Custodian and shall request delivery to
it of the Custodial File. The Custodian agrees, within five business days of
receipt of such Request for Release, to release the related Custodial File to
the Master Servicer or applicable Servicer.

      From time to time as is appropriate for the servicing or foreclosure of
any Mortgage Loan, the Master Servicer or applicable Servicer shall deliver to
the Custodian two copies of a Request for Release of a Servicing Officer
requesting that possession of the Custodial File be released to the Servicer or
Master Servicer and certifying as to the reason for such release. Upon receipt
of the foregoing, the Custodian shall deliver the Custodial File to the Master
Servicer or applicable Servicer. The Master Servicer or applicable Servicer
shall cause each Custodial File therein so released to be returned to the
Custodian when the need therefor by the Master Servicer or applicable Servicer
no longer exists, unless (i) the Mortgage Loan has been liquidated and the
Liquidation Proceeds relating to the Mortgage Loan have been deposited in the
Certificate Account to the extent required by the Pooling and Servicing
Agreement or (ii) the Custodial File or such document has been delivered to an
attorney, or to a public trustee or other public official as required by law,
for purposes of initiating or pursuing legal action or other proceedings for the
foreclosure of the Mortgaged Property either judicially or non-judicially. In
the event of the liquidation of a Mortgage Loan, the Master Servicer or
applicable Servicer shall deliver two copies of a Request for Release with
respect thereto to the Custodian upon deposit of the related Liquidation
Proceeds in the Certificate Account to the extent required by the Pooling and
Servicing Agreement.

      The Custodian shall maintain records (i) identifying all requests made by
Servicers or the Master Servicer (other than requests relating to Custodial
Files already released by the Custodian) for the release by the Custodian of
Custodial Files with respect to the Mortgage Loans and (ii) all Custodial Files
released by the Custodian.

      Section 2.6. Assumption Agreements. In the event that any assumption
agreement or substitution of liability agreement is entered into with respect to
any Mortgage Loan subject to this Agreement in accordance with the terms and
provisions of the Pooling and Servicing Agreement, the Master Servicer shall
notify the Custodian that such assumption or substitution agreement has been
completed by forwarding to the Custodian the original of such assumption or
substitution agreement, which copy shall be added to the related Custodial File
and, for all purposes, shall be considered a part of such Custodial File to the
same extent as all other documents and instruments constituting parts thereof.

                                   ARTICLE III

                            Concerning the Custodian

      Section 3.1. Custodian a Bailee and Agent of the Trustee. With respect to
each Mortgage Note, Mortgage and other documents constituting each Custodial
File which are delivered to the Custodian, the Custodian is exclusively the
bailee and agent of the Trustee, holds such documents for the benefit of
Certificateholders and undertakes to perform such duties and only such duties as
are specifically set forth in this Agreement and in the Pooling and Servicing
Agreement. All provisions of the Pooling and Servicing Agreement setting forth
duties of the Custodian in more detail are hereby incorporated by reference into
this Agreement. Except upon compliance with the provisions of Section 2.5 of
this Agreement and the provisions of the Pooling and Servicing Agreement, no
Mortgage Note or other document constituting a part of a Custodial File shall be
delivered by the Custodian to the Depositor or the Master Servicer or otherwise
released from the possession of the Custodian.

      Section 3.2. Indemnification. The Depositor hereby agrees to indemnify and
hold the Custodian harmless from and against all claims, liabilities, losses,
actions, suits or proceedings at law or in equity, or any other expenses, fees
or charges of any character or nature, which the Custodian may incur or with
which the Custodian may be threatened by reasons of its acting as custodian
under this Agreement, including indemnification of the Custodian against any and
all expenses, including attorney's fees if counsel for the Custodian has been
approved by the Depositor, and the cost of defending any action, suit or
proceedings or resisting any claim. Notwithstanding the foregoing, it is
specifically understood and agreed that in the event any such claim, liability,
loss, action, suit or proceeding or other expense, fees, or charge shall have
been caused by reason of any negligent act, negligent failure to act, or willful
misconduct on the part of the Custodian, or which shall constitute a willful
breach of its duties hereunder, the indemnification provisions of this Agreement
shall not apply.

      Section 3.3. Custodian May Own Certificates. The Custodian in its
individual or any other capacity may become the owner or pledgee of Certificates
with the same rights it would have if it were not Custodian.

      Section 3.4. Master Servicer to Pay Custodian's Fees and Expenses. The
Master Servicer covenants and agrees to pay to the Custodian from time to time,
and the Custodian shall be entitled to, reasonable compensation for all services
rendered by it in the exercise and performance of any of the powers and duties
hereunder of the Custodian, and the Master Servicer will pay or reimburse the
Custodian upon its request for all reasonable expenses, disbursements and
advances incurred or made by the Custodian in accordance with any of the
provisions of this Agreement (including the reasonable compensation and the
expenses and disbursements of its counsel and of all persons not regularly in
its employ), except any such expense, disbursement or advance as may arise from
its negligence or bad faith.

      Section 3.5. Custodian May Resign; Trustee May Remove Custodian. The
Custodian may resign from the obligations and duties hereby imposed upon it as
such obligations and duties relate to its acting as Custodian of the Mortgage
Loans. Upon receiving such notice of resignation, the Trustee shall either take
custody of the Custodial Files itself and give prompt notice thereof to the
Depositor, the Master Servicer and the Custodian or promptly appoint a successor
Custodian by written instrument, in duplicate, one copy of which instrument
shall be delivered to the resigning Custodian and one copy to the successor
Custodian. If the Trustee shall not have taken custody of the Custodial Files
and no successor Custodian shall have been so appointed and have accepted
resignation, the resigning Custodian may petition any court of competent
jurisdiction for the appointment of a successor Custodian.

      The Trustee, upon 60 days written notice, may remove the Custodian. In
such event, the Trustee shall appoint, or petition a court of competent
jurisdiction to appoint, a successor Custodian hereunder. Any successor
Custodian shall be a depository institution subject to supervision or
examination by federal or state authority and shall be able to satisfy the other
requirements contained in Section 3.7.

      Any resignation or removal of the Custodian and appointment of a successor
Custodian pursuant to any of the provisions of this Section 3.5 shall become
effective upon acceptance of appointment by the successor Custodian. The Trustee
shall give prompt notice to the Depositor and the Master Servicer of the
appointment of any successor Custodian. No successor Custodian shall have been
appointed and accepted appointment by the Trustee without the prior approval of
the Depositor and the Master Servicer.

      Section 3.6. Merger or Consolidation of Custodian. Any Person into which
the Custodian may be merged or converted or with which it may be consolidated,
or any Person resulting from any merger, conversion or consolidation to which
the Custodian shall be a party, or any Person succeeding to the business of the
Custodian, shall be the successor of the Custodian hereunder, without the
execution or filing of any paper or any further act on the part of any of the
parties hereto, anything herein to the contrary notwithstanding.

      The Custodian and such successor or surviving Person shall notify the
Depositor, the Master Servicer and the Trustee of any such merger, conversion or
consolidation at least two Business Days prior to the effective date thereof and
shall provide the Depositor and the Master Servicer with all information
required by the Depositor to comply with its reporting obligations not later
than the effective date of such merger, conversion or consolidation (unless
giving prior notice would be prohibited by applicable law or by a
confidentiality agreement, in which case notice shall be given by 12 noon
eastern time one Business Day after such merger or consolidation).

      Section 3.7. Representations of the Custodian. The Custodian hereby
represents that it is a depository institution subject to supervision or
examination by a federal or state authority, has a combined capital and surplus
of at least $10,000,000 and is qualified to do business in the jurisdiction in
which it will hold any Custodial File.

                                   ARTICLE IV

           Documents and Notices Required to be Delivered by Custodian

      Section 4.1 Assessment of Servicing Compliance; Registered Public
Accounting Firm Attestation Reports; Exchange Act Reporting. (a) The Custodian
shall furnish, or cause to be furnished in the case of clause (iii), to the
Master Servicer, no later than March 5 of each year or if such day is not a
Business Day, the next Business Day (with a 10 calendar day cure period, but in
no event later than March 15), commencing in March 2007, the following:

            (i) a report (in form and substance reasonably satisfactory to the
      Master Servicer and the Depositor) regarding the Custodian's assessment of
      compliance with the Servicing Criteria applicable to it during the
      immediately preceding calendar year, as required under Rules 13a-18 and
      15d-18 of the Exchange Act and Item 1122 of Regulation AB. Such report
      shall be addressed to the Master Servicer and signed by an authorized
      officer of the Custodian, and shall address, at a minimum, each of the
      Servicing Criteria applicable to the Custodian, as specified in the table
      in Exhibit R to the Pooling and Servicing Agreement;

            (ii) a report of a registered public accounting firm reasonably
      acceptable to the Master Servicer and the Depositor that attests to, and
      reports on, the assessment of compliance made by the Custodian and
      delivered pursuant to the preceding paragraph. Such attestation shall be
      in accordance with Rules 1-02(a)(3) and 2-02(g) of Regulation S-X under
      the Securities Act and the Exchange Act. If requested by the Master
      Servicer or the Depositor, such report shall contain or be accompanied by
      a consent of such accounting firm to inclusion or incorporation of such
      report in the Depositor's Registration Statement on Form S-3 relating to
      the Certificates and the Trust's Form 10-K; and

            (iii) an assessment of compliance and accountants' attestation as
      described in paragraphs (i) and (ii) of this Section 4.1(a) with respect
      to each Subcontractor determined by the Custodian pursuant to Section 4.2
      to be "participating in the servicing function" within the meaning of Item
      1122 of Regulation AB.

      An assessment of compliance provided by a Subcontractor pursuant to
Section 4.1(a)(iii) need not address any elements of the Servicing Criteria
applicable to it other than those specified by the Custodian pursuant to Section
4.2.

      No later than 30 days following the end of each fiscal year for the Trust
for which a Form 10-K is required to be filed, the Custodian shall forward to
the Master Servicer the name of each Subcontractor engaged by it and what
Relevant Servicing Criteria will be addressed in the report on assessment of
compliance prepared by such Subcontractor. When the Custodian submits its
assessment to the Master Servicer, it will also at such time include the
assessment (and attestation pursuant to Section 4.1(a)(ii) hereof) of each
Subcontractor engaged by it.

      (b) Within five (5) calendar days after a Distribution Date, the Custodian
shall provide to the Master Servicer, to the extent known, in EDGAR-compatible
format, or in such other form as otherwise agreed upon by the Master Servicer
and the Custodian, the form and substance of any Additional Form 10-D Disclosure
applicable to the Custodian, as indicated in the table in Exhibit S to the
Pooling and Servicing Agreement. The Custodian acknowledges that the performance
by the Master Servicer of its duties under Section 3.12(a) of the Pooling and
Servicing Agreement relating to the timely preparation and filing of Form 10-D
is contingent upon the Custodian strictly observing all applicable deadlines in
the performance of its duties under this Section 4.1(b).

      (c) No later than March 5 (with a 10 calendar day cure period, but in no
event later than March 15) of each year that the Trust is subject to the
Exchange Act reporting requirements, commencing in March 2007, the Custodian
shall provide to the Master Servicer, to the extent known, in EDGAR-compatible
format, or in such other form as otherwise agreed upon by the Master Servicer
and the Custodian, the form and substance of any Additional Form 10-K Disclosure
applicable to the Custodian, as indicated in the table in Exhibit T to the
Pooling and Servicing Agreement. The Custodian acknowledges that the performance
by the Master Servicer of its duties under Section 3.12(b) of the Pooling and
Servicing Agreement relating to the timely preparation and filing of Form 10-K
is contingent upon the Custodian strictly observing all applicable deadlines in
the performance of its duties under this Section 4.1(c).

      (d) For so long as the Trust is subject to the Exchange Act reporting
requirements, no later than the end of business on the second Business Day after
the occurrence of a Reportable Event applicable to the Custodian, the Custodian
shall provide to the Master Servicer, to the extent known, in EDGAR-compatible
format, or in such other form as otherwise agreed upon by the Master Servicer
and the Custodian, the form and substance of any Form 8-K Disclosure Information
applicable to the Custodian, as indicated in the table in Exhibit U to the
Pooling and Servicing Agreement. The Custodian acknowledges that the performance
by the Master Servicer of its duties under Section 3.12(c) of the Pooling and
Servicing Agreement relating to the timely preparation and filing of Form 8-K is
contingent upon the Custodian strictly observing all applicable deadlines in the
performance of its duties under this Section 4.1(d).

      (e) The Custodian shall indemnify the Master Servicer, each affiliate of
the Master Servicer, the Trust, each broker dealer acting as underwriter or
initial purchaser of the Certificates, each Person who controls any of such
parties and the Depositor (within the meaning of Section 15 of the Securities
Act and Section 20 of the Exchange Act); and the respective present and former
directors, officers, employees and agents of each of the foregoing and of the
Depositor (each such entity, an "Indemnified Party"), and shall hold each of
them harmless from and against any losses, damages, penalties, fines,
forfeitures, legal fees and expenses and related costs, judgments, and any other
costs, fees and expenses that any of them may sustain arising out of or based
upon:

                  (i) (A) any untrue statement of a material fact contained or
            alleged to be contained in any information, report, certification,
            accountants' letter or other material provided in written or
            electronic form under this Section 4.1 or Section 4.2 hereof by or
            on behalf of the Custodian, or provided under Sections 4.1 or 4.2 by
            or on behalf of any Subcontractor (collectively, the "Custodian
            Information"), or (B) the omission or alleged omission to state in
            the Custodian Information a material fact required to be stated in
            the Custodian Information or necessary in order to make the
            statements therein, in the light of the circumstances under which
            they were made, not misleading; provided, by way of clarification,
            that clause (B) of this paragraph shall be construed solely by
            reference to the Custodian Information and not to any other
            information communicated in connection with a sale or purchase of
            securities, without regard to whether the Custodian Information or
            any portion thereof is presented together with or separately from
            such other information; or

                  (ii) any failure by the Custodian or any Subcontractor engaged
            by the Custodian to deliver any information, report, certification,
            accountants' letter or other material when and as required under
            Sections 4.1 or 4.2, including any failure by the Custodian to
            identify pursuant to Section 4.2 any Subcontractor "participating in
            the servicing function" within the meaning of Item 1122 of
            Regulation AB.

      In the case of any failure of performance described in clause (ii) of this
Section, the Custodian shall promptly reimburse the Master Servicer and the
Depositor, as applicable, for all costs reasonably incurred by each such party
in order to obtain the information, report, certification, accountants' letter
or other material not delivered as required by the Custodian or any
Subcontractor. If the indemnification provided for herein is unavailable to hold
harmless any Indemnified Party, then the Custodian agrees that it shall
contribute to the amount paid or payable by such Indemnified Party as a result
of the losses, claims, damages or liabilities of such Indemnified Party in such
proportion as is appropriate to reflect the relative fault of such Indemnified
Party on the one hand and the Custodian on the other in connection with a breach
of the Custodian's obligations under this Section 4.1 or the Custodian's
negligence, bad faith or willful misconduct in connection therewith.

      4.2 Engagement of Affiliates or Third-Parties. The Custodian shall not
hire or otherwise utilize the services of any Subcontractor to fulfill any of
the obligations of the Custodian as servicer under this Agreement unless the
Custodian complies with the provisions of this Section.

      It shall not be necessary for the Custodian to seek the consent of the
Master Servicer or the Depositor to the utilization of any Subcontractor. The
Custodian shall promptly upon request provide to the Master Servicer (or any
designee of Master Servicer) a written description (in form and substance
satisfactory to the Master Servicer and the Depositor) of the role and function
of each Subcontractor utilized by the Custodian, specifying (i) the identity of
each such Subcontractor, (ii) which (if any) of such Subcontractors are
"participating in the servicing function" within the meaning of Item 1122 of
Regulation AB, and (iii) which elements of the Servicing Criteria will be
addressed in assessments of compliance provided by each Subcontractor identified
pursuant to clause (ii) of this paragraph.

      As a condition to the utilization of any Subcontractor determined to be
"participating in the servicing function" within the meaning of Item 1122 of
Regulation AB, the Custodian shall cause any such Subcontractor used by the
Custodian, for the benefit of the Master Servicer and the Depositor to comply
with the provisions of Section 4.1 of this Agreement to the same extent as if
such Subcontractor were the Custodian. The Custodian shall be responsible for
obtaining from each Subcontractor and delivering to the Master Servicer any
assessment of compliance and attestation required to be delivered by such
Subcontractor under Section 4.1, in each case as and when required to be
delivered.

      4.3 Errors and Omissions Policy. The Custodian shall maintain, at all
times and at its own expense, an insurance policy covering losses caused by
errors or omissions of the Custodian and its personnel (such policy, an "Errors
and Omissions Policy"), which policy shall have such terms and coverage amounts
as are comparable to those of errors and omissions policies maintained by
custodians of mortgage loans generally.

      The Errors and Omissions Policy shall insure the Custodian, its successors
and assigns, against any losses resulting from negligence, errors or omissions
on the part of officers, employees or other persons acting on behalf of the
Custodian in the performance of its duties as Custodian pursuant to this
Agreement.

      The Custodian shall maintain in effect the Errors and Omissions Policy at
all times and the Errors and Omissions Policy may not be canceled, permitted to
lapse or otherwise terminated without the acquisition of comparable coverage by
the Custodian.

      4.4 Compliance with Article IV. If (a) the Custodian fails to comply with
its obligations to deliver any assessment of servicing compliance or registered
public accounting firm attestation reports required pursuant to this Article IV
or (b) any Subcontractor engaged by the Custodian fails to comply with its
obligations to deliver any assessment of servicing compliance or registered
public accounting firm attestation reports, the Master Servicer, may, after
consultation with the Depositor, remove the Custodian and appoint a successor
custodian by written instrument, in duplicate, one copy of which instrument
shall be delivered to the Custodian so removed and one copy to the successor
custodian.

                                    ARTICLE V

                            Miscellaneous Provisions

      Section 5.1. Notices. All notices, requests, consents and demands and
other communications required under this Agreement, or pursuant to any other
instrument or document delivered hereunder shall be in writing and, unless
otherwise specifically provided, may be delivered personally, by telegram or
telex, or by registered or certified mail, postage prepaid, return receipt
requested, at the addresses specified on the signature page hereof (unless
changed by the particular party whose address is stated herein by similar notice
in writing), in which case the notice will be deemed delivered when received.

      Section 5.2. Amendments. No modification or amendment of or supplement to
this Agreement shall be valid or effective unless the same is in writing and
signed by all parties hereto, and neither the Depositor, the Master Servicer nor
the Trustee shall enter into any amendment hereof except as permitted by the
Pooling and Servicing Agreement. The Trustee shall give prompt written notice to
the Custodian of any amendment or supplement to the Pooling and Servicing
Agreement and furnish the Custodian with written copies thereof.

      Section 5.3. Governing Law. This Agreement shall be deemed a contract made
under the laws of the State of New York and shall be construed and enforced in
accordance with and governed by the laws of the State of New York.

      Section 5.4. Recordation of Agreement. To the extent permitted by
applicable law, this Agreement is subject to recordation in all appropriate
public offices for real property records in all the counties or other comparable
jurisdictions in which any or all of the properties subject to the Mortgages are
situated, and in any other appropriate public recording office or elsewhere,
such recordation to be effected by the Master Servicer and at its expense on
direction by the Trustee, but only upon direction accompanied by an Opinion of
Counsel to the effect that such recordation materially and beneficially affects
the interests of the Certificateholders.

      For the purpose of facilitating the recordation of this Agreement as
herein provided and for other purposes, this Agreement may be executed
simultaneously in any number of counterparts, each of which counterparts shall
be deemed to be an original, and such counterparts shall constitute but one and
the same instrument.

      Section 5.5. Severability of Provisions. If any one or more of the
covenants, agreements, provisions or terms of this Agreement shall be for any
reason whatsoever held invalid, then such covenants, agreements, provisions or
terms shall be deemed severable from the remaining covenants, agreements,
provisions or terms of this Agreement and shall in no way affect the validity or
enforceability of the other provisions of this Agreement or of the Certificates
or the rights of the holders thereof.

      Section 5.6. Regulation AB Compliance; Intent of Parties; Reasonableness.
The parties hereto acknowledge that interpretations of the requirements of
Regulation AB may change over time, whether due to interpretive guidance
provided by the Commission or its staff, consensus among participants in the
asset-backed securities markets, advice of counsel, or otherwise, and agree to
comply with requests made by the Depositor or the Master Servicer in good faith
for delivery of information under these provisions on the basis of evolving
interpretations of Regulation AB. In connection with the Trust, the parties
hereto shall cooperate fully with the Master Servicer and the Depositor to
deliver to the Master Servicer and/or the Depositor (including its assignees or
designees), any and all statements, reports, certifications, records and any
other information available to such party and reasonably necessary in the good
faith determination of the Depositor or the Master Servicer to permit the
Depositor or the Master Servicer to comply with the provisions of Regulation AB,
together with such disclosures reasonably believed by the Depositor or the
Master Servicer to be necessary in order to effect such compliance.


<PAGE>

            IN WITNESS WHEREOF, this Agreement is executed as of the date first
above written.

Address:                              U.S. BANK NATIONAL ASSOCIATION,
                                         as Trustee

209 South LaSalle Street
Chicago, IL 60604                     By:__________________________________
                                      Name:  Melissa A. Rosal
                                      Title:    Vice President


Address:                              WELLS FARGO ASSET SECURITIES CORPORATION,
                                         as Depositor

7430 New Technology Way
Frederick, Maryland 21703             By:__________________________________
                                      Name:  Bradley A. Davis
                                      Title:    Vice President


Address:                              WELLS FARGO BANK, N.A.,
                                         as Master Servicer

9062 Old Annapolis Road
Columbia, Maryland 21045              By:__________________________________
                                      Name:  Jennifer L. Richardson
                                      Title:    Assistant Vice President


Address:                              WELLS FARGO BANK, N.A.,
                                         as Custodian

1015 10th Avenue South East
Minneapolis, Minnesota 55414          By:___________________________________
                                         Name: Mary B. Hogan
                                         Title:   Vice President

<PAGE>

STATE OF MARYLAND       )
                        ss.:
COUNTY OF FREDERICK     )


      On this 30th day of March, 2006, before me, a notary public in and for the
State of Maryland, personally appeared Bradley A. Davis, known to me who, being
by me duly sworn, did depose and say that he resides at Cooksville, Maryland;
that he is a Vice President of Wells Fargo Asset Securities Corporation, a
Delaware corporation, one of the parties that executed the foregoing instrument;
and that he signed his name thereto by order of the Board of Directors of said
corporation.

-------------------------
Notary Public

[NOTARIAL SEAL]

<PAGE>

STATE OF MARYLAND       )
                        ss.:
COUNTY OF HOWARD        )


      On this 30th day of March 2006, before me, a notary public in and for the
State of Maryland, personally appeared Jennifer L. Richardson, known to me who,
being by me duly sworn, did depose and say that she resides in Riva, Maryland;
that she is a Vice President of Wells Fargo Bank, N.A., a national banking
association, one of the parties that executed the foregoing instrument; and that
she signed her name thereto by order of the Board of Directors of said
association.

-------------------------
Notary Public

[NOTARIAL SEAL]



<PAGE>

STATE OF ILLINOIS       )
                        ss.:
COUNTY OF COOK          )

      On this 30th day of March 2006, before me, a notary public in and for the
State of Illinois, personally appeared Melissa A. Rosal, known to me who, being
by me duly sworn, did depose and say that she resides in Chicago, Illinois; that
she is a Vice President of U.S. Bank National Association, a national banking
association, one of the parties that executed the foregoing instrument; and that
she signed her name thereto by order of the Board of Directors of said
association.

-------------------------
Notary Public

[NOTARIAL SEAL]



<PAGE>



STATE OF MINNESOTA      )
                        ss.:
COUNTY OF HENNEPIN      )


      On this 30th day of March 2006, before me, a notary public in and for the
State of Minnesota, personally appeared Mary B. Hogan, known to me who, being by
me duly sworn, did depose and say that she resides in Maple Grove, Minnesota;
that she is a Vice President of Wells Fargo Bank, N.A., a national banking
association, one of the parties that executed the foregoing instrument; and that
she signed her name thereto by order of the Board of Directors of said
association.

-------------------------
Notary Public

[NOTARIAL SEAL]


<PAGE>

                                    EXHIBIT F

                 Addresses for Requesting Mortgage Loan Schedule

In the case of the Depositor:

Wells Fargo Asset Securities Corporation
7430 New Technology Way
Frederick, Maryland 21703
Attention: Vice President - Structured Finance

In the case of the Master Servicer:

Wells Fargo Bank, N.A.
9062 Old Annapolis Road
Columbia, Maryland 21045-1951
Attention: Corporate Trust Services - WFMBS 2006-4


<PAGE>


                                    EXHIBIT G

                        REQUEST FOR RELEASE OF DOCUMENTS

To:   Wells Fargo Bank, N.A.
      1015 10th Avenue S.E.
      Minneapolis., MN  55414
      Attn:  ________________

      Re:   Custodial Agreement, dated as of March 30, 2006, among U.S. Bank
            National Association, as Trustee, Wells Fargo Asset Securities
            Corporation, as Depositor, Wells Fargo Bank, N.A., as Master
            Servicer, and Wells Fargo Bank, N.A., as Custodian, relating to the
            Wells Fargo Asset Securities Corporation; Mortgage Pass-Through
            Certificates, Series 2006-4.

            In connection with the administration of the Mortgage Loans held by
you as Custodian for the Trust Estate pursuant to the above-captioned Custodial
Agreement, we request the release, and hereby acknowledge receipt, of the
Custodian's Owner Mortgage Loan File for the Mortgage Loan described below, for
the reason indicated.

                              Mortgage Loan Number:
                              ---------------------

                       Mortgagor Name, Address & Zip Code:
                       -----------------------------------


            Reason for Requesting Documents (check one):

            _______           1.    Mortgage Paid in Full

            _______           2.    Foreclosure

            _______           3.    Substitution

            _______           4.    Other Liquidation (Repurchases, etc.)

            _______           5.    Nonliquidation

            Reason:____________________________________

            By:_______________________________________
                 (authorized signer)

            Issuer:_____________________________________



            Address:___________________________________

                    ___________________________________



            Date:_______________________________________

                                    Custodian

Wells Fargo Bank, N.A.

            Please acknowledge the execution of the above request by your
signature and date below:

------------------------------------                  -----------------
Signature                                             Date

Documents returned to Custodian:

------------------------------------                  -----------------
Custodian                                              Date


<PAGE>

                                    EXHIBIT H

                                            AFFIDAVIT   PURSUANT   TO  SECTION
                                            860E(e)(4)    OF   THE    INTERNAL
                                            REVENUE CODE OF 1986,  AS AMENDED,
                                            AND FOR NON-ERISA INVESTORS



STATE OF                )
                        )  ss.:
COUNTY OF               )


             [NAME OF OFFICER], being first duly sworn, deposes and says:

            1.  That he is [Title of Officer] of [Name of Purchaser] (the
"Purchaser"), a [description of type of entity] duly organized and existing
under the laws of the [State of ] [United States], on behalf of which he makes
this affidavit.

            2.  That  the  Purchaser's  Taxpayer  Identification  Number  is
[             ].

            3.  That the Purchaser is not a "disqualified organization" within
the meaning of Section 860E(e)(5),of the Internal Revenue Code of 1986, as
amended (the "Code"), or an ERISA Prohibited Holder, and will not be a
"disqualified organization" or an ERISA Prohibited Holder, as of [date of
transfer], and that the Purchaser is not acquiring Wells Fargo Asset Securities
Corporation Mortgage Pass-Through Certificates, Series 2006-4, Class I-A-R
Certificate (the "Residual Certificate") for the account of, or as agent
(including a broker, nominee, or other middleman) for, any person or entity from
which it has not received an affidavit substantially in the form of this
affidavit. For these purposes, a "disqualified organization" means the United
States, any state or political subdivision thereof, any foreign government, any
international organization, any agency or instrumentality of any of the
foregoing (other than an instrumentality if all of its activities are subject to
tax and a majority of its board of directors is not selected by such
governmental entity), any cooperative organization furnishing electric energy or
providing telephone service to persons in rural areas as described in Code
Section 1381(a)(2)(C), or any organization (other than a farmers' cooperative
described in Code Section 521) that is exempt from taxation under the Code
unless such organization is subject to the tax on unrelated business income
imposed by Code Section 511. For these purposes, an "ERISA Prohibited Holder"
means an employee benefit plan or other retirement arrangement subject to Title
I of the Employee Retirement Income Security Act of 1974, as amended ("ERISA"),
or Code Section 4975 or a governmental plan, as defined in Section 3(32) of
ERISA, subject to any federal, state or local law which is, to a material
extent, similar to the foregoing provisions of ERISA or the Code (collectively,
a "Plan") or a Person acting on behalf of or investing the assets of such a
Plan.

            4.  That the Purchaser historically has paid its debts as they
have come due and intends to pay its debts as they come due in the future and
the Purchaser intends to pay taxes associated with holding the Residual
Certificate as they become due.

            5.  That the Purchaser understands that it may incur tax
liabilities with respect to the Residual Certificate in excess of cash flows
generated by the Residual Certificate.

            6.  That the Purchaser will not transfer the Residual Certificate
to any person or entity from which the Purchaser has not received an affidavit
substantially in the form of this affidavit and as to which the Purchaser has
actual knowledge that the requirements set forth in paragraph 3, 4 or 10 hereof
are not satisfied or that the Purchaser has reason to know does not satisfy the
requirements set forth in paragraph 4 hereof.

            7.  That the Purchaser is aware that the Residual Certificate may
be a "noneconomic residual interest" within the meaning of Treasury regulations
promulgated pursuant to the Code and that the transferor of a noneconomic
residual interest will remain liable for any taxes due with respect to the
income on such residual interest, unless no significant purpose of the transfer
was to impede the assessment or collection of tax.

            8.  That the Purchaser will not cause income from the Residual
Certificate to be attributable to a foreign permanent establishment or fixed
base, within the meaning of an applicable income tax treaty, of the Purchaser or
any other person.

            9.  That, if the Purchaser is purchasing the Residual Certificate
in a transfer intended to meet the safe harbor provisions of Treasury
Regulations Sections 1.860E-1(c), the Purchaser has executed and attached
Attachment A hereto.

            10.  That the Purchaser (i) is a U.S. Person or (ii) is a person
other than a U.S. Person (a "Non-U.S. Person") that holds the Residual
Certificate in connection with the conduct of a trade or business within the
United States and has furnished the transferor and the Trustee with an effective
Internal Revenue Service Form W-8ECI or successor form at the time and in the
manner required by the Code or (iii) is a Non-U.S. Person that has delivered to
both the transferor and the Trustee an opinion of a nationally recognized tax
counsel to the effect that the transfer of the Residual Certificate to it is in
accordance with the requirements of the Code and the regulations promulgated
thereunder and that such transfer of the Residual Certificate will not be
disregarded for federal income tax purposes. "U.S. Person" means a citizen or
resident of the United States, a corporation or partnership (unless, in the case
of a partnership, Treasury regulations are adopted that provide otherwise)
created or organized in or under the laws of the United States, any state
thereof or the District of Columbia, including an entity treated as a
corporation or partnership for federal income tax purposes, an estate whose
income is subject to United States federal income tax regardless of its source,
or a trust if a court within the United States is able to exercise primary
supervision over the administration of such trust, and one or more such U.S.
Persons have the authority to control all substantial decisions of such trust
(or, to the extent provided in applicable Treasury regulations, certain trusts
in existence on August 20, 1996 which are eligible to elect to be treated as
U.S. Persons).

            11.  That the Purchaser agrees to such amendments of the Pooling
and Servicing Agreement as may be required to further effectuate the
restrictions on transfer of the Residual Certificate to such a "disqualified
organization," an agent thereof, an ERISA Prohibited Holder or a person that
does not satisfy the requirements of paragraph 4, paragraph 5 and paragraph 10
hereof.

            12.  That the Purchaser consents to the designation of the Master
Servicer as its agent to act as "tax matters person" of each REMIC pursuant to
Section 8.13 of the Pooling and Servicing Agreement, and if such designation is
not permitted by the Code and applicable law, to act as tax matters person if
requested to do so.


<PAGE>

            IN WITNESS WHEREOF, the Purchaser has caused this instrument to be
executed on its behalf, pursuant to authority of its Board of Directors, by its
[Title of Officer] this ___ day of , 20__.

                                        [NAME OF PURCHASER]



                                       By:____________________________________
                                          [Name of Officer]
                                          [Title of Officer]

            Personally appeared before me the above-named [Name of Officer],
known or proved to me to be the same person who executed the foregoing
instrument and to be the [Title of Officer], of the Purchaser, and acknowledged
to me that he [she] executed the same as his [her] free act and deed and the
free act and deed of the Purchaser.

            Subscribed and sworn before me this __ day of           , 20__.



Notary Public

COUNTY OF____________________

STATE OF_____________________

My commission expires the __ day of __________, 20__.

<PAGE>


                                  ATTACHMENT A

                                       to

   AFFIDAVIT PURSUANT TO SECTION 860E(e)(4) OF THE INTERNAL REVENUE CODE OF
                1986, AS AMENDED, AND FOR NON-ERISA INVESTORS


Check the appropriate box:

[ ]   The consideration paid to the Purchaser to acquire the Residual
      Certificate equals or exceeds the excess of (a) the present value of the
      anticipated tax liabilities over (b) the present value of the anticipated
      savings associated with holding such Certificate, in each case calculated
      in accordance with U.S. Treasury Regulations Sections 1.860E-1(c)(7) and
      (8), computing present values using a discount rate equal to the
      short-term Federal rate prescribed by Section 1274(d) of the Code and the
      compounding period used by the Purchaser.

                                       OR

[ ]   The transfer of the Residual Certificate complies with U.S. Treasury
      Regulations Sections 1.860E-1(c)(5) and (6) and, accordingly:

      (i)   the Purchaser is an "eligible corporation," as defined in U.S.
            Treasury Regulations Section 1.860E-1(c)(6)(i), as to which income
            from Residual Certificate will only be taxed in the United States;

      (ii)  at the time of the transfer, and at the close of the Purchaser's two
            fiscal years preceding the year of the transfer, the Purchaser had
            gross assets for financial reporting purposes (excluding any
            obligation of a person related to the Purchaser within the meaning
            of U.S. Treasury Regulations Section 1.860E-1(c)(6)(ii)) in excess
            of $100 million and net assets in excess of $10 million;

      (iii) the Purchaser will transfer the Residual Certificate only to another
            "eligible corporation," as defined in U.S. Treasury Regulations
            Section 1.860E-1(c)(6)(i), in a transaction that satisfies the
            requirements of Sections 1.860E-1(c)(4)(i), (ii) and (iii) and
            Section 1.860E-1(c)(5) of the U.S. Treasury Regulations;

      (iv)  the Purchaser has determined the consideration paid to it to acquire
            the Residual Certificate based on reasonable market assumptions
            (including, but not limited to, borrowing and investment rates,
            prepayment and loss assumptions, expense and reinvestment
            assumptions, tax rates and other factors specific to the Purchaser)
            that it has determined in good faith; and

      (v)   in the event of any transfer of the Residual Certificate by the
            Purchaser, the Purchaser will require its transferee to complete a
            representation in the form of this Attachment A as a condition of
            the transferee's purchase of the Residual Certificate.


<PAGE>

                                    EXHIBIT I

                Letter from Transferor of Residual Certificate

                                     [Date]

Wells Fargo Bank, N.A.
9062 Old Annapolis Road
Columbia, Maryland 21045-1951
Attn: Corporate Trust Services WFMBS 2006-4

Re:   Wells Fargo Asset Securities Corporation,
      Series 2006-4, Class I-A-R

Ladies and Gentlemen:

      [Transferor] has reviewed the attached affidavit of [Transferee], and has
no actual knowledge that such affidavit is not true and has no reason to know
that the information contained in paragraph 4 thereof is not true.

                                       Very truly yours,

                                       [Transferor]

                                       ----------------------


<PAGE>

                                    EXHIBIT J

                   WELLS FARGO ASSET SECURITIES CORPORATION

                       MORTGAGE PASS-THROUGH CERTIFICATES
                                  SERIES 2006-4
       CLASS [I-B-4][I-B-5][I-B-6][II-B-4][II-B-5][II-B-6] CERTIFICATES

                               TRANSFEREE'S LETTER

                                                    ----------------- --, ----

Wells Fargo Bank, N.A.
9062 Old Annapolis Road
Columbia, Maryland 21045-1951
Attn: Corporate Trust Services WFMBS 2006-4

Wells Fargo Asset Securities Corporation
7430 New Technology Way
Frederick, Maryland 21703

      The undersigned (the "Purchaser") proposes to purchase Wells Fargo Asset
Securities Corporation Mortgage Pass-Through Certificates, Series 2006-4, Class
[I-B-4][I-B-5][I-B-6][II-B-4][II-B-5][II-B-6] Certificates (the "Class
[I-B-4][I-B-5][I-B-6][II-B-4][II-B-5][II-B-6] Certificates") in the principal
amount of $___________. In doing so, the Purchaser hereby acknowledges and
agrees as follows:

      Section 1. Definitions. Each capitalized term used herein and not
otherwise defined herein shall have the meaning ascribed to it in the Pooling
and Servicing Agreement, dated as of March 30, 2006 (the "Pooling and Servicing
Agreement") among Wells Fargo Asset Securities Corporation, as depositor (the
"Depositor"), Wells Fargo Bank, N.A., as master servicer (the "Master Servicer")
and U.S. Bank National Association, as trustee (the "Trustee"), of Wells Fargo
Asset Securities Corporation Mortgage Pass-Through Certificates, Series 2006-4.

      Section 2. Representations and Warranties of the Purchaser. In connection
with the proposed transfer, the Purchaser represents and warrants to the
Depositor, the Master Servicer and the Trustee that:

      (a) The Purchaser is duly organized, validly existing and in good standing
under the laws of the jurisdiction in which the Purchaser is organized, is
authorized to invest in the Class [I-B-4][I-B-5][I-B-6][II-B-4][II-B-5][II-B-6]
Certificates, and to enter into this Agreement, and duly executed and delivered
this Agreement.

      (b) The Purchaser is acquiring the Class
[I-B-4][I-B-5][I-B-6][II-B-4][II-B-5][II-B-6] Certificates for its own account
as principal and not with a view to the distribution thereof, in whole or in
part.

      [(c) The Purchaser has knowledge of financial and business matters and is
capable of evaluating the merits and risks of an investment in the Class
[I-B-4][I-B-5][I-B-6][II-B-4][II-B-5][II-B-6] Certificates; the Purchaser has
sought such accounting, legal and tax advice as it has considered necessary to
make an informed investment decision; and the Purchaser is able to bear the
economic risk of an investment in the Class
[I-B-4][I-B-5][I-B-6][II-B-4][II-B-5][II-B-6] Certificates and can afford a
complete loss of such investment.]

      [(c)__The Purchaser is a "Qualified Institutional Buyer" within the
meaning of Rule 144A of the Act.]

      (d) The Purchaser confirms that (a) it has received and reviewed a copy of
the Private Placement Memorandum dated March 27, 2006, relating to the Class
[I-B-4][I-B-5][I-B-6][II-B-4][II-B-5][II-B-6] Certificates and reviewed, to the
extent it deemed appropriate, the documents attached thereto or incorporated by
reference therein, (b) it has had the opportunity to ask questions of, and
receive answers from the Depositor concerning the Class
[I-B-4][I-B-5][I-B-6][II-B-4][II-B-5][II-B-6] Certificates and all matters
relating thereto, and obtain any additional information (including documents)
relevant to its decision to purchase the Class
[I-B-4][I-B-5][I-B-6][II-B-4][II-B-5][II-B-6] Certificates that the Depositor
possesses or can possess without unreasonable effort or expense and (c) it has
undertaken its own independent analysis of the investment in the Class
[I-B-4][I-B-5][I-B-6][II-B-4][II-B-5][II-B-6] Certificates. The Purchaser will
not use or disclose any information it receives in connection with its purchase
of the Class [I-B-4][I-B-5][I-B-6][II-B-4][II-B-5][II-B-6] Certificates other
than in connection with a subsequent sale of Class
[I-B-4][I-B-5][I-B-6][II-B-4][II-B-5][II-B-6] Certificates.

      (e) Either (i) the Purchaser is not an employee benefit plan or other
retirement arrangement subject to Title I of the Employee Retirement Income
Security Act of 1974, as amended, ("ERISA"), or Section 4975 of the Internal
Revenue Code of 1986, as amended (the "Code"), or a governmental plan, as
defined in Section 3(32) of ERISA subject to any federal, state or local law
("Similar Law") which is, to a material extent, similar to the foregoing
provisions of ERISA or the Code (collectively, a "Plan"), an agent acting on
behalf of a Plan, or a person utilizing the assets of a Plan or (ii) if the
Purchaser is an insurance company, (A) the source of funds used to purchase the
Class [I-B-4][I-B-5][I-B-6][II-B-4][II-B-5][II-B-6] Certificate is an "insurance
company general account" (as such term is defined in Section V(e) of Prohibited
Transaction Class Exemption 95-60 ("PTE 95-60"), 60 Fed. Reg. 35925 (July 12,
1995), (B) there is no Plan with respect to which the amount of such general
account's reserves and liabilities for the contract(s) held by or on behalf of
such Plan and all other Plans maintained by the same employer (or affiliate
thereof as defined in Section V(a)(1) of PTE 95-60) or by the same employee
organization exceeds 10% of the total of all reserves and liabilities of such
general account (as such amounts are determined under Section I(a) of PTE 95-60)
at the date of acquisition and (C) the purchase and holding of such Class
[I-B-4][I-B-5][I-B-6][II-B-4][II-B-5][II-B-6] Certificates are covered by
Sections I and III of PTE 95-60 or (iii) the Purchaser has provided (a) a
"Benefit Plan Opinion" satisfactory to the Depositor and the Master Servicer of
the Trust Estate and (b) such other opinions of counsel, officers' certificates
and agreements as the Depositor or the Master Servicer may have required. A
Benefit Plan Opinion is an opinion of counsel to the effect that the proposed
transfer will not constitute or result in a non-exempt prohibited transaction
within the meaning of ERISA, Section 4975 of the Code or Similar Law and will
not subject the Depositor or the Master Servicer to any obligation in addition
to those undertaken in the Pooling and Servicing Agreement (including any
liability for civil penalties or excise taxes imposed pursuant to ERISA, Section
4975 of the Code or Similar Law).

      (f) If the Purchaser is a depository institution subject to the
jurisdiction of the Office of the Comptroller of the Currency ("OCC"), the Board
of Governors of the Federal Reserve System ("FRB"), the Federal Deposit
Insurance Corporation ("FDIC"), the Office of Thrift Supervision ("OTS") or the
National Credit Union Administration ("NCUA"), the Purchaser has reviewed the
"Supervisory Policy Statement on Securities Activities" dated January 28, 1992
of the Federal Financial Institutions Examination Council and the April 15, 1994
Interim Revision thereto as adopted by the OCC, FRB, FDIC, OTS and NCUA (with
modifications as applicable), as appropriate, other applicable investment
authority, rules, supervisory policies and guidelines of these agencies and, to
the extent appropriate, state banking authorities and has concluded that its
purchase of the Class [I-B-4][I-B-5][I-B-6][II-B-4][II-B-5][II-B-6] Certificates
is in compliance therewith.

      Section 3. Transfer of Class [I-B-4][I-B-5][I-B-6][II-B-4][II-B-5][II-B-6]
Certificates.

      (a) The Purchaser understands that the Class
[I-B-4][I-B-5][I-B-6][II-B-4][II-B-5][II-B-6] Certificates have not been
registered under the Securities Act of 1933 (the "Act") or any state securities
laws and that no transfer may be made unless the Class
[I-B-4][I-B-5][I-B-6][II-B-4][II-B-5][II-B-6] Certificates are registered under
the Act and applicable state law or unless an exemption from registration is
available. The Purchaser further understands that neither the Depositor nor the
Master Servicer is under any obligation to register the Class
[I-B-4][I-B-5][I-B-6][II-B-4][II-B-5][II-B-6] Certificates or make an exemption
available. In the event that such a transfer is to be made in reliance upon an
exemption from the Act or applicable state securities laws, (i) the Master
Servicer shall require, in order to assure compliance with such laws, that the
Certificateholder's prospective transferee certify to the Depositor and the
Master Servicer as to the factual basis for the registration or qualification
exemption relied upon, and (ii) unless the transferee is a "Qualified
Institutional Buyer" within the meaning of Rule 144A of the Act, the Master
Servicer or the Depositor may, if such transfer is made within three years from
the later of (a) the Closing Date or (b) the last date on which the Depositor or
any affiliate thereof was a holder of the Certificates proposed to be
transferred, require an Opinion of Counsel that such transfer may be made
pursuant to an exemption from the Act and state securities laws, which Opinion
of Counsel shall not be an expense of the Master Servicer or the Depositor. Any
such Certificateholder desiring to effect such transfer shall, and does hereby
agree to, indemnify the Trustee, the Master Servicer, any Paying Agent and the
Depositor against any liability that may result if the transfer is not so exempt
or is not made in accordance with such federal and state laws.

      (b) No transfer of a Class [I-B-4][I-B-5][I-B-6][II-B-4][II-B-5][II-B-6]
Certificate shall be made unless the transferee provides the Depositor and the
Master Servicer with a Transferee's Letter, substantially in the form of this
Agreement.

      The Purchaser acknowledges that its Class
[I-B-4][I-B-5][I-B-6][II-B-4][II-B-5][II-B-6] Certificates bear a legend setting
forth the applicable restrictions on transfer.


<PAGE>

            IN WITNESS WHEREOF, the undersigned has caused this Agreement to be
validly executed by its duly authorized representative as of the day and the
year first above written.

                                       [PURCHASER]

                                       By: ______________________________


                                       Its: ______________________________


<PAGE>

                                    EXHIBIT K

                           LIST OF RECORDATION STATES

                                     Florida

                                    Maryland


<PAGE>

                                    EXHIBIT L

                              SERVICING AGREEMENTS

                      Wells Fargo Bank Servicing Agreement



      [Included as Exhibit 10.1 to the Current Report on Form 8-K pursuant
            to which this Pooling and Servicing Agreement is filed]


<PAGE>

                                    EXHIBIT M

                      [FORM OF SPECIAL SERVICING AGREEMENT]

                 SPECIAL SERVICING AND COLLATERAL FUND AGREEMENT


      This SPECIAL SERVICING AND COLLATERAL FUND AGREEMENT (the "Agreement") is
made and entered into as of [ ], between Wells Fargo Bank, N.A. (the "Company"
or the "Master Servicer") and [ ] (the "Purchaser").

                              PRELIMINARY STATEMENT

      The Purchaser is the holder of the entire interest in Wells Fargo Asset
Securities Corporation Mortgage Pass-Through Certificates, Series [ ], Class [ ]
(the "Class B Certificates"), which are the Lowest Priority Certificates (as
defined below) outstanding with respect to such Series. The Class B Certificates
were issued pursuant to a Pooling and Servicing Agreement dated as of [ ] among
Wells Fargo Asset Securities Corporation, as depositor (the "Depositor"), Wells
Fargo Bank, N.A., as Master Servicer and U.S. Bank National Association, as
Trustee.

      In connection with the ownership by the Purchaser of the Lowest Priority
Certificates, the Purchaser and the Company have agreed that (i) the Purchaser,
for so long as it owns 100% of the Lowest Priority Certificates, will have the
unilateral right to control foreclosure decisions with respect to delinquent
mortgage loans and (ii) the Company will provide to the Purchaser certain
information with respect to the Mortgage Loans;

      The parties hereto have agreed that the Company will cause, to the extent
that the Company as Master Servicer is granted such authority in the related
Servicing Agreements, the related servicers (each a related "Servicer"), which
service the Mortgage Loans which comprise the Trust Estate related to the above
referenced series under the related servicing agreements (each a related
"Servicing Agreement"), to engage in certain special servicing procedures
relating to foreclosures for the benefit of the Purchaser, and that the
Purchaser will deposit funds in a collateral fund to cover any losses
attributable to such procedures as well as all advances and costs in connection
therewith, as set forth herein.

      In consideration of the mutual agreements herein contained, the receipt
and sufficiency of which are hereby acknowledged, the Company and the Purchaser
agree that the following provisions shall become effective and shall be binding
on and enforceable by the Company and the Purchaser:


                                    ARTICLE I

                                   DEFINITIONS

      Section 1.02. Defined Terms.

      Whenever used in this Agreement, the following words and phrases, unless
the context otherwise requires, shall have the following meanings:

      Business Day: Any day other than (i) a Saturday or a Sunday or (ii) a day
on which banking institutions in the State of New York are required or
authorized by law or executive order to be closed.

      Collateral Fund: The fund established and maintained pursuant to Section
3.01 hereof.

      Collateral Fund Permitted Investments: Either (i) obligations of, or
obligations fully guaranteed as to principal and interest by, the United States,
or any agency or instrumentality thereof, provided such obligations are backed
by the full faith and credit of the United States, (ii) a money market fund
rated in the highest rating category by a nationally recognized rating agency
selected by the Company, (iii) cash, (iv) mortgage pass-through certificates
issued or guaranteed by Government National Mortgage Association, FNMA or FHLMC,
(v) commercial paper (including both non-interest-bearing discount obligations
and interest-bearing obligations payable on demand or on a specified date), the
issuer of which may be an affiliate of the Company, having at the time of such
investment a rating of at least F-1 by Fitch Ratings ("Fitch"), at least P-1 by
Moody's Investors Service, Inc. ("Moody's") or at least A-1 by Standard &
Poor's, a division of The McGraw-Hill Companies, Inc. ("S&P") or (vi) demand and
time deposits in, certificates of deposit of, any depository institution or
trust company (which may be an affiliate of the Company) incorporated under the
laws of the United States of America or any state thereof and subject to
supervision and examination by federal and/or state banking authorities, so long
as at the time of such investment either (x) the long-term debt obligations of
such depository institution or trust company have a rating of at least AA by
Fitch, Aa2 by Moody's or AA by S&P, (y) the certificate of deposit or other
unsecured short-term debt obligations of such depository institution or trust
company have a rating of at least F-1 by Fitch, P-1 by Moody's or A-1 by S&P or
(z) the depository institution or trust company is one that is acceptable to any
of Fitch, Moody's or S&P and, for each of the preceding clauses (i), (iv), (v)
and (vi), the maturity thereof shall be not later than the earlier to occur of
(A) 30 days from the date of the related investment and (B) the next succeeding
Distribution Date as defined in the related Pooling and Servicing Agreement.

      Commencement of Foreclosure: The first official action required under
local law in order to commence foreclosure proceedings or to schedule a
trustee's sale under a deed of trust, including (i) in the case of a mortgage,
any filing or service of process necessary to commence an action to foreclose,
or (ii) in the case of a deed of trust, posting, the publishing, filing or
delivery of a notice of sale, but not including in either case (x) any notice of
default, notice of intent to foreclose or sell or any other action prerequisite
to the actions specified in (i) or (ii) above, (y) the acceptance of a
deed-in-lieu of foreclosure (whether in connection with a sale of the related
property or otherwise) or (z) initiation and completion of a short pay-off.

      Current Appraisal: With respect to any Mortgage Loan as to which the
Purchaser has made an Election to Delay Foreclosure, an appraisal of the related
Mortgaged Property obtained by the Purchaser at its own expense from an
independent appraiser (which shall not be an affiliate of the Purchaser)
acceptable to the Company as nearly contemporaneously as practicable to the time
of the Purchaser's election, prepared based on the Company's customary
requirements for such appraisals.

      Election to Delay Foreclosure: Any election by the Purchaser to delay the
Commencement of Foreclosure, made in accordance with Section 2.02(b).

      Election to Foreclose: Any election by the Purchaser to proceed with the
Commencement of Foreclosure, made in accordance with Section 2.03(a).

      Lowest Priority Certificates: The most subordinate class of certificates
issued under the Pooling and Servicing Agreement that is outstanding from time
to time. If the Lowest Priority Certificates are reduced to zero as a result of
losses or otherwise, and if the Purchaser at that time owns 100% of the most
subordinate class of certificates issued under the Pooling and Servicing
Agreement then remaining outstanding, then such most subordinate class remaining
outstanding shall thereafter be deemed to be the Lowest Priority Certificates
for all purposes of this Agreement.

      Monthly Advances: Principal and interest advances and servicing advances
including costs and expenses of foreclosure.

      Required Collateral Fund Balance: As of any date of determination, an
amount equal to the aggregate of all amounts previously required to be deposited
in the Collateral Fund pursuant to Section 2.02(d) (after adjustment for all
withdrawals and deposits pursuant to Section 2.02(e)) and Section 2.03(b) (after
adjustment for all withdrawals and deposits pursuant to Section 2.03(c)) and
Section 3.02 to be reduced by all withdrawals therefrom pursuant to Section
2.02(g) and Section 2.03(d).

      Section 1.03. Definitions Incorporated by Reference.

      All capitalized terms not otherwise defined in this Agreement shall have
the meanings assigned in the Pooling and Servicing Agreement.


                                   ARTICLE II

                          SPECIAL SERVICING PROCEDURES

      Section 2.01. eports and Notices.

      (a) In connection with the performance of its duties under the Pooling and
Servicing Agreement relating to the realization upon defaulted Mortgage Loans,
the Company as Master Servicer shall provide to the Purchaser the following
notices and reports:

      Within five Business Days after each Distribution Date (or included in or
      with the monthly statements to Certificateholders pursuant to the Pooling
      and Servicing Agreement), the Company shall provide to the Purchaser a
      report identifying all loans delinquent 30 days or more (including all
      loans in foreclosure, bankruptcy or "real estate owned" status) (each, a
      "Delinquency Report"). The Delinquency Report shall use the same
      methodology and calculations employed in the Company's standard servicing
      reports, indicating the number of Mortgage Loans that are (i) thirty days
      delinquent, (ii) sixty days delinquent, (iii) ninety days or more
      delinquent, (iv) in foreclosure, (v) in bankruptcy or (vi) real estate
      owned, and indicating for each such Mortgage Loan the loan number, the
      property address and the outstanding principal balance.

      (b) If requested by the Purchaser, the Company shall cause the Servicer
(to the extent that the Company as Master Servicer is granted such authority in
the related Servicing Agreement) to make its servicing personnel available
(during their normal business hours) to respond to reasonable inquiries, by
phone or in writing by facsimile, electronic, or overnight mail transmission, by
the Purchaser in connection with any Mortgage Loan (i) identified in a report
under Section 2.01 (a) (ii), (a) (iii), (a) (iv), (a) (v) or (a) (vi); provided,
that (1) the related Servicer shall only be required to provide information that
is readily accessible to its servicing personnel and (2) the related Servicer
shall respond within five Business Days orally or in writing by facsimile
transmission.

      (c) In addition to the foregoing, the Company shall cause the Servicer (to
the extent that the Company as Master Servicer is granted such authority in the
related Servicing Agreement) to provide to the Company (for prompt transmission
to the Purchaser) such information as the Purchaser may reasonably request
provided, however, that such information is consistent with normal reporting
practices, concerning each Mortgage Loan that is at least ninety days delinquent
and each Mortgage Loan which has become real estate owned, through the final
liquidation thereof; provided, that the related Servicer shall only be required
to provide information that is readily accessible to its servicing personnel;
provided, however, that the Purchaser will reimburse the Company and the related
Servicer for any out of pocket expenses.

      Section 2.02. Purchaser's Election to Delay Foreclosure Proceedings.

      (a) The Purchaser shall be deemed to direct the Company to direct (to the
extent that the Company as Master Servicer is granted such authority in the
related Servicing Agreement) the related Servicer that in the event that the
Company does not receive written notice of the Purchaser's election pursuant to
subsection (b) below within 48 hours (exclusive of any intervening non-Business
Days) of transmission of the Delinquency Report provided by the Company under
Section 2.01 (a) (subject to extension as set forth in Section 2.02(b), the
related Servicer may proceed with the Commencement of Foreclosure in respect of
each Mortgage Loan reported under Section 2.01 (a)(ii) or 2.01 (a)(iii) in
accordance with its normal foreclosure policies without further notice to the
Purchaser. Any foreclosure that has been initiated may be discontinued (i)
without notice to the Purchaser if the Mortgage Loan has been brought current or
if a refinancing or prepayment occurs with respect to the Mortgage Loan
(including by means of a short payoff approved by the related Servicer) or (ii)
if the related Servicer has reached the terms of a forbearance agreement with
the borrower.

      (b) In connection with any Mortgage Loan reported in a Delinquency Report
under Section 2.01(a)(ii) or 2.01 (a)(iii), the Purchaser may elect to instruct
the Company to cause, to the extent that the Company as Master Servicer is
granted such authority in the related Servicing Agreement, the related Servicer
to delay the Commencement of Foreclosure until such time as the Purchaser
determines that the related Servicer may proceed with the Commencement of
Foreclosure. Such election must be evidenced by written notice received within
48 hours (exclusive of any intervening non-Business Days) of transmission of the
Delinquency Report provided by the Company under Section 2.01(a). Such 48 hour
period shall be extended for no longer than an additional four Business Days
after the receipt of the information if the Purchaser requests additional
information related to such foreclosure; provided, however, that the Purchaser
will have at least one Business Day to respond to any requested additional
information. Any such additional information shall be provided only to the
extent it is obtainable by the related Servicer from existing reports,
certificates or statements or is otherwise readily accessible to its servicing
personnel. The Purchaser agrees that it has no right to deal with the mortgagor
during such period. However, if such servicing activities include acceptance of
a deed-in-lieu of foreclosure or short payoff, the Purchaser will be notified
and given two Business Days to respond.

      (c) With respect to any Mortgage Loan as to which the Purchaser has made
an Election to Delay Foreclosure, the Purchaser shall obtain a Current Appraisal
as soon as practicable, but in no event more than 15 Business Days thereafter,
and shall provide the Company with a copy of such Current Appraisal.

      (d) Within two Business Days of making any Election to Delay Foreclosure,
the Purchaser shall remit by wire transfer to the Company, for deposit in the
Collateral Fund, an amount, as calculated by the Company, equal to the sum of
(i) 125% of the greater of the unpaid principal balance of the Mortgage Loan and
the value shown in the Current Appraisal referred to in subsection (c) above
(or, if such Current Appraisal has not yet been obtained, the Company's estimate
thereof, in which case the required deposit under this subsection shall be
adjusted upon obtaining such Current Appraisal), and (ii) three months' interest
on the Mortgage Loan at the applicable Mortgage Interest Rate. If any Election
to Delay Foreclosure extends for a period in excess of three months (such excess
period being referred to herein as the "Excess Period"), within two Business
Days the Purchaser shall remit by wire transfer in advance to the Company for
deposit in the Collateral Fund the amount of each additional month's interest,
as calculated by the Company, equal to interest on the Mortgage Loan at the
applicable Mortgage Interest Rate for the Excess Period. The terms of this
Agreement will no longer apply to the servicing of any Mortgage Loan upon the
failure of the Purchaser to deposit any of the above amounts relating to the
Mortgage Loan within two Business Days of the Election to Delay Foreclosure or
within two Business Days of the commencement of the Excess Period subject to
Section 3.01.

      (e) With respect to any Mortgage Loan as to which the Purchaser has made
an Election to Delay Foreclosure, the Company may withdraw from the Collateral
Fund from time to time amounts necessary to reimburse the related Servicer for
all related Monthly Advances and Liquidation Expenses thereafter made by such
Servicer in accordance with the Pooling and Servicing Agreement and the related
Servicing Agreement. To the extent that the amount of any such Liquidation
Expenses is determined by the Company based on estimated costs, and the actual
costs are subsequently determined to be higher, the Company may withdraw the
additional amount from the Collateral Fund. In the event that the Mortgage Loan
is brought current by the mortgagor and the foreclosure action is discontinued,
the amounts so withdrawn from the Collateral Fund shall be redeposited if and to
the extent that reimbursement therefor from amounts paid by the mortgagor is not
prohibited pursuant to the Pooling and Servicing Agreement or the related
Servicing Agreement, applicable law or the related mortgage note. Except as
provided in the preceding sentence, amounts withdrawn from the Collateral Fund
to cover Monthly Advances and Liquidation Expenses shall not be redeposited
therein or otherwise reimbursed to the Purchaser. If and when any such Mortgage
Loan is brought current by the mortgagor, all amounts remaining in the
Collateral Fund in respect of such Mortgage Loan (after adjustment for all
permitted withdrawals and deposits pursuant to this subsection) shall be
released to the Purchaser.

      (f) With respect to any Mortgage Loan as to which the Purchaser has made
an Election to Delay Foreclosure, the related Servicer shall continue to service
the Mortgage Loan in accordance with its customary procedures (other than the
delay in Commencement of Foreclosure as provided herein). If and when the
Purchaser shall notify the Company that it believes that it is appropriate to do
so, the related Servicer may proceed with the Commencement of Foreclosure. In
any event, if the Mortgage Loan is not brought current by the mortgagor by the
time the loan becomes 6 months delinquent, the Purchaser's election shall no
longer be effective and at the Purchaser's option, either (i) the Purchaser
shall purchase the Mortgage Loan from the related Trust Estate at a purchase
price equal to the sum of (x) accrued and unpaid interest on the Mortgage Loan
at the applicable Mortgage Interest Rate through the last day of the month of
repurchase, (y) 100% of the unpaid principal balance of the Mortgage Loan as of
such purchase date and (z) any additional amount needed to reimburse any
unreimbursed related Periodic Advance or other servicing advances made in
respect of such Mortgage Loan, to be paid by (A) applying any balance in the
Collateral Fund to such purchase price, and (B) to the extent of any deficiency,
by wire transfer of immediately available funds from the Purchaser to the
Company for deposit in the related Certificate Account; or (ii) the related
Servicer shall proceed with the Commencement of Foreclosure. In the event that
the Purchaser purchases any such Mortgage Loan, the Servicer shall continue to
service the Mortgage Loan for the Purchaser pursuant to the applicable Servicing
Agreement.

      (g) Upon the occurrence of a liquidation with respect to any Mortgage Loan
as to which the Purchaser made an Election to Delay Foreclosure and as to which
the related Servicer proceeded with the Commencement of Foreclosure in
accordance with subsection (f) above, the Company shall calculate the amount, if
any, by which the value shown on the Current Appraisal obtained under subsection
(c) exceeds the actual sales price obtained for the related Mortgaged Property
(net of Liquidation Expenses and accrued interest related to the extended
foreclosure period), and the Company shall withdraw the amount of such excess
from the Collateral Fund, shall remit the same to the Trust Estate and in its
capacity as Master Servicer shall apply such amount as additional Liquidation
Proceeds pursuant to the Pooling and Servicing Agreement. After making such
withdrawal, all amounts remaining in the Collateral Fund in respect of such
Mortgage Loan (after adjustment for all permitted withdrawals and deposits
pursuant to this Agreement) shall be released to the Purchaser.

      Section 2.03. Purchaser's Election to Commence Foreclosure Proceedings.

      (a) In connection with any Mortgage Loan identified in a Delinquency
Report under Section 2.01(a)(ii), the Purchaser, for so long as the Purchaser
owns 100% of the Lowest Priority Certificates, may elect to instruct the Company
to cause, to the extent that the Company as Master Servicer is granted such
authority in the related Servicing Agreement, the related Servicer to proceed
with the Commencement of Foreclosure as soon as practicable. Such election must
be evidenced by written notice received by the Company by 5:00 p.m., New York
City time, on the third Business Day following the delivery of such Delinquency
Report.

      (b) Within two Business Days of making any Election to Foreclose, the
Purchaser shall remit to the Company, for deposit in the Collateral Fund, an
amount, as calculated by the Company, equal to 125% of the current unpaid
principal balance of the Mortgage Loan and three months interest on the Mortgage
Loan at the applicable Mortgage Interest Rate. If and when any such Mortgage
Loan is brought current by the mortgagor, all amounts in the Collateral Fund in
respect of such Mortgage Loan (after adjustment for all permitted withdrawals
and deposits pursuant to this Agreement) shall be released to the Purchaser if
and to the extent that reimbursement therefor from amounts paid by the mortgagor
is not prohibited pursuant to the Pooling and Servicing Agreement or the related
Servicing Agreement, applicable law or the related mortgage note. The terms of
this Agreement will no longer apply to the servicing of any Mortgage Loan upon
the failure of the Purchaser to deposit the above amounts relating to the
Mortgage Loan within two Business Days of the Election to Foreclose subject to
Section 3.01.

      (c) With respect to any Mortgage Loan as to which the Purchaser has made
an Election to Foreclose, the related Servicer shall continue to service the
Mortgage Loan in accordance with its customary procedures (other than
Commencement of Foreclosure as provided herein). In connection therewith, the
Company shall have the same rights to make withdrawals for Monthly Advances and
Liquidations Expenses from the Collateral Fund as are provided under Section
2.02(e), and the Company shall make reimbursements thereto to the limited extent
provided under such subsection in accordance with its customary procedures. The
Company shall not be required to cause, to the extent that the Company as Master
Servicer is granted such authority in the related Servicing Agreement, the
related Servicer to proceed with the Commencement of Foreclosure if (i) the same
is stayed as a result of the mortgagor's bankruptcy or is otherwise barred by
applicable law, or to the extent that all legal conditions precedent thereto
have not yet been complied with, or (ii) the Company believes there is a breach
of representations or warranties by the Company, a Servicer, or the Depositor,
which may result in a repurchase or substitution of such Mortgage Loan, or (iii)
the Company or related Servicer reasonably believes the Mortgaged Property may
be contaminated with or affected by hazardous wastes or hazardous substances
(and, without limiting the related Servicer's right not to proceed with the
Commencement of Foreclosure, the Company supplies the Purchaser with information
supporting such belief). Any foreclosure that has been initiated may be
discontinued (x) without notice to the Purchaser if the Mortgage Loan has been
brought current or if a refinancing or prepayment occurs with respect to the
Mortgage Loan (including by means of a short payoff) or (y) if the related
Servicer has reached the terms of a forbearance agreement.

      (d) Upon the occurrence of a liquidation with respect to any Mortgage Loan
as to which the Purchaser made an Election to Foreclose and as to which the
related Servicer proceeded with the Commencement of Foreclosure in accordance
with subsection (c) above, the Company shall calculate the amount, if any, by
which the unpaid principal balance of the Mortgage Loan at the time of
liquidation (plus all unreimbursed interest and servicing advances and
Liquidation Expenses in connection therewith other than those paid from the
Collateral Fund) exceeds the actual sales price obtained for the related
Mortgaged Property, and the Company shall withdraw the amount of such excess
from the Collateral Fund, shall remit the same to the Trust Estate and in its
capacity as Master Servicer shall apply such amount as additional Liquidation
Proceeds pursuant to the Pooling and Servicing Agreement. After making such
withdrawal, all amounts remaining in the Collateral Fund (after adjustment for
all withdrawals and deposits pursuant to subsection (c) in respect of such
Mortgage Loan shall be released to the Purchaser.

      Section 2.04. Termination.

      (a) With respect to all Mortgage Loans included in the Trust Estate, the
Purchaser's right to make any Election to Delay Foreclosure or any Election to
Foreclose and the Company's obligations under Section 2.01 shall terminate (i)
at such time as the Principal Balance of the Class B Certificates has been
reduced to zero, (ii) if the greater of (x) 43% (or such lower or higher
percentage that represents the related Servicer's actual historical loss
experience with respect to the Mortgage Loans in the related pool as determined
by the Company) of the aggregate principal balance of all Mortgage Loans that
are in foreclosure or are more than 90 days delinquent on a contractual basis
and REO properties or (y) the aggregate amount that the Company estimates
through the normal servicing practices of the related Servicer will be required
to be withdrawn from the Collateral Fund with respect to Mortgage Loans as to
which the Purchaser has made an Election to Delay Foreclosure or an Election to
Foreclosure, exceeds (z) the then-current principal balance of the Class B
Certificates, (iii) upon any transfer by the Purchaser of any interest (other
than the minority interest therein, but only if the transferee provides written
acknowledgment to the Company of the Purchaser's right hereunder and that such
transferee will have no rights hereunder) in the Class B Certificates (whether
or not such transfer is registered under the Pooling and Servicing Agreement),
including any such transfer in connection with a termination of the Trust Estate
or (iv) upon any breach of the terms of this Agreement by the Purchaser.

      (b) Except as set forth in 2.04(a), this Agreement and the respective
rights, obligations and responsibilities of the Purchaser and the Company
hereunder shall terminate upon the later to occur of (i) the final liquidation
of the last Mortgage Loan as to which the Purchaser made any Election to Delay
Foreclosure or any Election to Foreclose and the withdrawal of all remaining
amounts in the Collateral Fund as provided herein and (ii) ten Business Days'
notice. The Purchaser's right to make an election pursuant to Section 2.02 or
Section 2.03 hereof with respect to a particular Mortgage Loan shall terminate
if the Purchaser fails to make any deposit required pursuant to Section 2.02(d)
or 2.03(b) or if the Purchaser fails to make any other deposit to the Collateral
Fund pursuant to this Agreement.

                                  ARTICLE III

                       COLLATERAL FUND; SECURITY INTEREST

      Section 3.01. Collateral Fund.

      Upon receipt from the Purchaser of the initial amount required to be
deposited in the Collateral Fund pursuant to Article II, the Company shall
establish and maintain with [ ] as a segregated account on its books and records
an account (the "Collateral Fund"), entitled "Wells Fargo Bank, N.A., as Master
Servicer, for the benefit of registered holders of Wells Fargo Asset Securities
Corporation Mortgage Pass-Through Certificates, Series [ ]." Amounts held in the
Collateral Fund shall continue to be the property of the Purchaser, subject to
the first priority security interest granted hereunder for the benefit of the
Certificateholders, until withdrawn from the Collateral Fund pursuant to Section
2.02 or 2.03 hereof. The Collateral Fund shall be an "outside reserve fund"
within the meaning of the REMIC Provisions, beneficially owned by the Purchaser
for federal income tax purposes. All income, gain, deduction or loss with
respect to the Collateral Fund shall be that of the Purchaser. All distributions
from the Trust Fund to the Collateral Fund shall be treated as distributed to
the Purchaser as the beneficial owner thereof.

      Upon the termination of this Agreement and the liquidation of all Mortgage
Loans as to which the Purchaser has made any Election to Delay Foreclosure or
any Election to Foreclose pursuant to Section 2.04 hereof, the Company shall
distribute or cause to be distributed to the Purchaser all amounts remaining in
the Collateral Fund (after adjustment for all deposits and permitted withdrawals
pursuant to this Agreement) together with any investment earnings thereon. In
the event the Purchaser has made any Election to Delay Foreclosure or any
Election to Foreclose, prior to any distribution to the Purchaser of all amounts
remaining in the Collateral Fund, funds in the Collateral Fund shall be applied
consistent with the terms of this Agreement.

      Section 3.02. Collateral Fund Permitted Investments.

      The Company shall, at the written direction of the Purchaser, invest the
funds in the Collateral Fund in Collateral Fund Permitted Investments. Such
direction shall not be changed more frequently than quarterly. In the absence of
any direction, the Company shall select such investments in accordance with the
definition of Collateral Fund Permitted Investments in its discretion. All
income and gain realized from any investment as well as any interest earned on
deposits in the Collateral Fund (net of any losses on such investments) and any
payments of principal made in respect of any Collateral Fund Permitted
Investment shall be deposited in the Collateral Fund upon receipt. All costs and
realized losses associated with the purchase and sale of Collateral Fund
Permitted Investments shall be borne by the Purchaser and the amount of net
realized losses shall be deposited by the Purchaser in the Collateral Fund
promptly upon realization. The Company shall periodically (but not more
frequently than monthly) distribute to the Purchaser upon request an amount of
cash, to the extent cash is available therefore in the Collateral Fund, equal to
the amount by which the balance of the Collateral Fund, after giving effect to
all other distributions to be made from the Collateral Fund on such date,
exceeds the Required Collateral Fund Balance. Any amounts so distributed shall
be released from the lien and security interest of this Agreement.

      Section 3.03. Grant of Security Interest.

      The Purchaser hereby grants to the Company for the benefit of the
Certificateholders under the Pooling and Servicing Agreement a security interest
in and lien on all of the Purchaser's right, title and interest, whether now
owned or hereafter acquired, in and to: (1) the Collateral Fund, (2) all amounts
deposited in the Collateral Fund and Collateral Fund Permitted Investments in
which such amounts are invested (and the distributions and proceeds of such
investments) and (3) all cash and non-cash proceeds of any of the foregoing,
including proceeds of the voluntary conversion thereof (all of the foregoing
collectively, the "Collateral").

      The Purchaser acknowledges the lien on and the security interest in the
Collateral for the benefit of the Certificateholders. The Purchaser shall take
all actions requested by the Company as may be reasonably necessary to perfect
the security interest created under this Agreement in the Collateral and cause
it to be prior to all other security interests and liens, including the
execution and delivery to the Company for filing of appropriate financing
statements in accordance with applicable law. The Company shall file appropriate
continuation statements, or appoint an agent on its behalf to file such
statements, in accordance with applicable law.

      Section 3.04. Collateral Shortfalls.

      In the event that amounts on deposit in the Collateral Fund at any time
are insufficient to cover any withdrawals therefrom that the Company is then
entitled to make hereunder, the Purchaser shall be obligated to pay such amounts
to the Company immediately upon demand. Such obligation shall constitute a
general corporate obligation of the Purchaser. The failure to pay such amounts
within two Business Days of such demand (except for amounts to cover interest on
a Mortgage Loan pursuant to Sections 2.02(d) and 2.03 (b)), shall cause an
immediate termination of the Purchaser's right to make any Election to Delay
Foreclosure or Election to Foreclose and the Company's obligations under this
Agreement with respect to all Mortgage Loans to which such insufficiencies
relate, without the necessity of any further notice or demand on the part of the
Company.

                                   ARTICLE IV

      Section 4.01. Assessment of Servicing Compliance; Registered Public
Accounting Firm Attestation Reports; Exchange Act Reporting.

      (a) The Purchaser shall furnish, or cause to be furnished in the case of
clause (iii), to the Master Servicer, no later than March 5 of each year or if
such day is not a Business Day, the next Business Day (with a 10 calendar day
cure period, but in no event later than March 15), commencing in March 20 , the
following:

            (i) a report (in form and substance reasonably satisfactory to the
      Master Servicer and the Depositor) regarding the Purchaser's assessment of
      compliance with the Servicing Criteria applicable to it during the
      immediately preceding calendar year, as required under Rules 13a-18 and
      15d-18 of the Exchange Act and Item 1122 of Regulation AB. Such report
      shall be addressed to the Master Servicer and signed by an authorized
      officer of the Purchaser, and shall address, at a minimum, each of the
      Servicing Criteria applicable to the Purchaser;

            (ii) a report of a registered public accounting firm reasonably
      acceptable to the Master Servicer and the Depositor that attests to, and
      reports on, the assessment of compliance made by the Purchaser and
      delivered pursuant to the preceding paragraph. Such attestation shall be
      in accordance with Rules 1-02(a)(3) and 2-02(g) of Regulation S-X under
      the Securities Act and the Exchange Act. If requested by the Master
      Servicer or the Depositor, such report shall contain or be accompanied by
      a consent of such accounting firm to inclusion or incorporation of such
      report in the Depositor's Registration Statement on Form S-3 relating to
      the Certificates and the Trust's Form 10-K; and

            (iii) an assessment of compliance and accountants' attestation as
      described in paragraphs (i) and (ii) of this Section 4.01(a) with respect
      to each Subcontractor determined by the Purchaser pursuant to Section 4.02
      to be "participating in the servicing function" within the meaning of Item
      1122 of Regulation AB.

      An assessment of compliance provided by a Subcontractor pursuant to
Section 4.01(a)(iii) need not address any elements of the Servicing Criteria
applicable to it other than those specified by the Purchaser pursuant to Section
4.02.

      No later than 30 days following the end of each fiscal year for the Trust
for which a Form 10-K is required to be filed, the Purchaser shall forward to
the Master Servicer the name of each Subcontractor engaged by it and what
Servicing Criteria will be addressed in the report on assessment of compliance
prepared by such Subcontractor. When the Purchaser submits its assessment to the
Master Servicer, it will also at such time include the assessment (and
attestation pursuant to Section 4.01(a)(ii) hereof) of each Subcontractor
engaged by it.

      (b) Within five (5) calendar days after a Distribution Date, the Purchaser
shall provide to the Master Servicer, to the extent known, in EDGAR-compatible
format, or in such other form as otherwise agreed upon by the Master Servicer
and the Purchaser, the form and substance of any Additional Form 10-D Disclosure
applicable to the Purchaser, as indicated in the table in Exhibit S to the
Pooling and Servicing Agreement. The Purchaser acknowledges that the performance
by the Master Servicer of its duties under Section 3.12(a) of the Pooling and
Servicing Agreement relating to the timely preparation and filing of Form 10-D
is contingent upon the Purchaser strictly observing all applicable deadlines in
the performance of its duties under this Section 4.01(b).

      (c) No later than March 5 (with a 10 calendar day cure period, but in no
event later than March 15) of each year that the Trust is subject to the
Exchange Act reporting requirements, commencing in March 20 , the Purchaser
shall provide to the Master Servicer, to the extent known, in EDGAR-compatible
format, or in such other form as otherwise agreed upon by the Master Servicer
and the Purchaser, the form and substance of any Additional Form 10-K Disclosure
applicable to the Purchaser, as indicated in the table in Exhibit T to the
Pooling and Servicing Agreement. The Purchaser acknowledges that the performance
by the Master Servicer of its duties under Section 3.12(b) of the Pooling and
Servicing Agreement relating to the timely preparation and filing of Form 10-K
is contingent upon the Purchaser strictly observing all applicable deadlines in
the performance of its duties under this Section 4.01(c).

      (d) For so long as the Trust is subject to the Exchange Act reporting
requirements, no later than the end of business on the second Business Day after
the occurrence of a Reportable Event applicable to the Purchaser, the Purchaser
shall provide to the Master Servicer, to the extent known, in EDGAR-compatible
format, or in such other form as otherwise agreed upon by the Master Servicer
and the Purchaser, the form and substance of any Form 8-K Disclosure Information
applicable to the Purchaser, as indicated in the table in Exhibit U to the
Pooling and Servicing Agreement. The Purchaser acknowledges that the performance
by the Master Servicer of its duties under Section 3.12(c) of the Pooling and
Servicing Agreement relating to the timely preparation and filing of Form 8-K is
contingent upon the Purchaser strictly observing all applicable deadlines in the
performance of its duties under this Section 4.01(d).

      (e) The Purchaser shall provide such information regarding itself as the
Master Servicer or the Depositor request for the purpose of complying with Item
1108 of Regulation AB, including at a minimum, the information set forth in
Exhibit A.

      (f) The Purchaser shall indemnify the Master Servicer, each affiliate of
the Master Servicer, the Trust, each broker dealer acting as underwriter or
initial purchaser of the Certificates, each Person who controls any of such
parties and the Depositor (within the meaning of Section 15 of the Securities
Act and Section 20 of the Exchange Act); and the respective present and former
directors, officers, employees and agents of each of the foregoing and of the
Depositor (each such entity, an "Indemnified Party"), and shall hold each of
them harmless from and against any losses, damages, penalties, fines,
forfeitures, legal fees and expenses and related costs, judgments, and any other
costs, fees and expenses that any of them may sustain arising out of or based
upon:

            (i) (A) any untrue statement of a material fact contained or alleged
      to be contained in any information, report, certification, accountants'
      letter or other material provided in written or electronic form under this
      Section 4.01 or Section 4.02 hereof by or on behalf of the Purchaser, or
      provided under Sections 4.01 or 4.02 by or on behalf of any Subcontractor
      (collectively, the "Purchaser Information"), or (B) the omission or
      alleged omission to state in the Purchaser Information a material fact
      required to be stated in the Purchaser Information or necessary in order
      to make the statements therein, in the light of the circumstances under
      which they were made, not misleading; provided, by way of clarification,
      that clause (B) of this paragraph shall be construed solely by reference
      to the Purchaser Information and not to any other information communicated
      in connection with a sale or purchase of securities, without regard to
      whether the Purchaser Information or any portion thereof is presented
      together with or separately from such other information; or

            (ii) any failure by the Purchaser or any Subcontractor engaged by
      the Purchaser to deliver any information, report, certification,
      accountants' letter or other material when and as required under Sections
      4.01 or 4.02, including any failure by the Purchaser to identify pursuant
      to Section 4.02 any Subcontractor "participating in the servicing
      function" within the meaning of Item 1122 of Regulation AB.

      In the case of any failure of performance described in clause (ii) of this
Section, the Purchaser shall promptly reimburse the Master Servicer and the
Depositor, as applicable, for all costs reasonably incurred by each such party
in order to obtain the information, report, certification, accountants' letter
or other material not delivered as required by the Purchaser or any
Subcontractor. If the indemnification provided for herein is unavailable to hold
harmless any Indemnified Party, then the Purchaser agrees that it shall
contribute to the amount paid or payable by such Indemnified Party as a result
of the losses, claims, damages or liabilities of such Indemnified Party in such
proportion as is appropriate to reflect the relative fault of such Indemnified
Party on the one hand and the Purchaser on the other in connection with a breach
of the Purchaser's obligations under this Section 4.1 or the Purchaser's
negligence, bad faith or willful misconduct in connection therewith.

      (g) Notwithstanding anything contained in this Section 4.01 to the
contrary, the provisions of this Section 4.01 shall not apply to the Purchaser
with respect to any calendar year unless the Purchaser exercises its rights set
forth under Sections 2.02 or 2.03 of this Agreement in such calendar year.

      Section 4.02. Engagement of Affiliates or Third-Parties.

      The Purchaser shall not hire any Subservicer without the consent of the
Master Servicer and the Depositor. The Purchaser shall not hire or otherwise
utilize the services of any Subcontractor to fulfill any of the obligations of
the Purchaser as servicer under this Agreement unless the Purchaser complies
with the provisions of this Section.

      It shall not be necessary for the Purchaser to seek the consent of the
Master Servicer or the Depositor to the utilization of any Subcontractor. The
Purchaser shall promptly upon request provide to the Master Servicer (or any
designee of Master Servicer) a written description (in form and substance
satisfactory to the Master Servicer and the Depositor) of the role and function
of each Subcontractor utilized by the Purchaser, specifying (i) the identity of
each such Subcontractor, (ii) which (if any) of such Subcontractors are
"participating in the servicing function" within the meaning of Item 1122 of
Regulation AB, and (iii) which elements of the Servicing Criteria will be
addressed in assessments of compliance provided by each Subcontractor identified
pursuant to clause (ii) of this paragraph.

      As a condition to the utilization of any Subcontractor determined to be
"participating in the servicing function" within the meaning of Item 1122 of
Regulation AB, the Purchaser shall cause any such Subcontractor used by the
Purchaser, for the benefit of the Master Servicer and the Depositor to comply
with the provisions of Section 4.01 of this Agreement to the same extent as if
such Subcontractor were the Purchaser. The Purchaser shall be responsible for
obtaining from each Subcontractor and delivering to the Master Servicer any
assessment of compliance and attestation required to be delivered by such
Subcontractor under Section 4.01, in each case as and when required to be
delivered.

      Section 4.03. Notification of Merger.

            The Purchaser and such successor or surviving  Person shall notify
the  Depositor,  the  Master  Servicer  and the  Trustee  of any such  merger,
conversion or  consolidation at least two Business Days prior to the effective
date thereof and shall provide the Depositor and the Master  Servicer with all
information   required  by  the   Depositor  to  comply  with  its   reporting
obligations  not later than the effective  date of such merger,  conversion or
consolidation  (unless  giving prior notice would be  prohibited by applicable
law or by a confidentiality  agreement, in which case notice shall be given by
12 noon eastern time one Business Day after such merger or consolidation).

      Section 4.04. Compliance with Article IV.

      If (a) the Purchaser fails to comply with its obligations to deliver any
assessment of servicing compliance or registered public accounting firm
attestation reports required pursuant to this Article IV or (b) any
Subcontractor engaged by the Purchaser fails to comply with its obligations to
deliver any assessment of servicing compliance or registered public accounting
firm attestation reports, the Master Servicer, may, after consultation with the
Depositor, terminate this Agreement pursuant to Section 2.04(a)(iv).

                                   ARTICLE V

                            MISCELLANEOUS PROVISIONS

      Section 5.01. Amendment.

      This Agreement may be amended from time to time by the Company and the
Purchaser by written agreement signed by the Company and the Purchaser, subject
to the acknowledgement of the Rating Agencies as contemplated in Section 3.08 of
the Pooling and Servicing Agreement with respect to such amendment.

      Section 5.02. Counterparts.

      This Agreement may be executed simultaneously in any number of
counterparts, each of which counterparts shall be deemed to be an original, and
such counterparts shall constitute but one and the same instrument.

      Section 5.03. Governing Law.

      This Agreement shall be construed in accordance with the laws of the State
of New York and the obligations, rights and remedies of the parties hereunder
shall be determined in accordance with such laws.

      Section 5.04. Notices.

      All demands, notices and direction hereunder shall be in writing or by
telecopy and shall be deemed effective upon receipt to:

      (a)   in the case of the Company,
            Wells Fargo Bank, N.A.
            9062 Old Annapolis Road
            Columbia, MD 21045

            Attention: Vice President, Master Servicing
            Phone: 410-884-2000
            Fax: 410-715-1573

      (b) in the case of the Purchaser,

      Section 5.05. Severability of Provisions.

      If any one or more of the covenants, agreements, provisions or terms of
this Agreement shall be for any reason whatsoever, including regulatory, held
invalid, then such covenants, agreements, provisions or terms of this Agreement
and shall in no way affect the validity or enforceability of the other
provisions of this Agreement.

      Section 5.06. Successors and Assigns.

The provisions of this Agreement shall be binding upon and inure to the benefit
of the respective successors and assigns of the parties hereto, and all such
provisions shall inure to the benefit of the Certificateholders; provided,
however, that the rights under this Agreement cannot be assigned by the
Purchaser without the consent of the Company.

      Section 5.07. Article and Section Headings.

      The article and section headings herein are for convenience of reference
only and shall not limit or otherwise affect the meaning hereof.

      Section 5.08. Confidentiality.

      The Purchaser agrees that all information supplied by or on behalf of the
Company pursuant to Sections 2.01 or 2.02, including individual account
information, is the property of the Company and the Purchaser agrees to hold
such information confidential and not to disclose such information.

      Each party hereto agrees that neither it, nor any officer, director,
employee, affiliate or independent contractor acting at such party's direction
will disclose the terms of Section 5.09 of this Agreement to any person or
entity other than such party's legal counsel except pursuant to a final,
non-appealable order of court, the pendency of such order the other party will
have received notice of at least five business days prior to the date thereof,
or pursuant to the other party's prior express written consent.

      Section 5.09. Indemnification.

      The Purchaser agrees to indemnify and hold harmless the Company, the
Depositor, and each Servicer and each person who controls the Company, the
Depositor, or a Servicer and each of their respective officers, directors,
affiliates and agents acting at the Company's, the Depositor's, or a Servicer's
direction (the "Indemnified Parties") against any and all losses, claims,
damages or liabilities to which they may be subject, insofar as such losses,
claims, damages or liabilities (or actions in respect thereof) arise out of, or
are based upon, actions taken by, or actions not taken by, the Company, the
Depositor, or a Servicer, or on their behalf, in accordance with the provisions
of this Agreement and (i) which actions conflict with the Company's, the
Depositor's, or a Servicer's obligations under the Pooling and Servicing
Agreement or the related Servicing Agreement, or (ii) give rise to securities
law liability under federal or state securities laws with respect to the
Certificates. The Purchaser hereby agrees to reimburse the Indemnified Parties
for the reasonable legal or other expenses incurred by them in connection with
investigating or defending any such loss, claim, damage, liability or action.
The indemnification obligations of the Purchaser hereunder shall survive the
termination or expiration of this Agreement.

      Section 5.10 Regulation AB Compliance; Intent of Parties; Reasonableness.

      The parties hereto acknowledge that interpretations of the requirements of
Regulation AB may change over time, whether due to interpretive guidance
provided by the Commission or its staff, consensus among participants in the
asset-backed securities markets, advice of counsel, or otherwise, and agree to
comply with requests made by the Depositor or the Master Servicer in good faith
for delivery of information under these provisions on the basis of evolving
interpretations of Regulation AB. In connection with the Trust, the parties
hereto shall cooperate fully with the Master Servicer and the Depositor to
deliver to the Master Servicer and/or the Depositor (including its assignees or
designees), any and all statements, reports, certifications, records and any
other information available to such party and reasonably necessary in the good
faith determination of the Depositor or the Master Servicer to permit the
Depositor or the Master Servicer to comply with the provisions of Regulation AB,
together with such disclosures reasonably believed by the Depositor or the
Master Servicer to be necessary in order to effect such compliance.

<PAGE>

      IN WITNESS WHEREOF, the Company and the Purchaser have caused their names
to be signed hereto by their respective officers thereunto duly authorized, all
as of the day and year first above written.

                                    WELLS FARGO BANK, N.A.



                                    By: ___________________________________
                                      Name:
                                      Title:

                                    [NAME OF PURCHASER]



                                    By: ___________________________________
                                      Name:
                                      Title:


<PAGE>

                                                                       EXHIBIT A

                              PURCHASER INFORMATION

      (A) the Purchaser's form of organization;

      (B) a description of how long the Purchaser has been servicing residential
mortgage loans; a general discussion of the Purchaser's experience in servicing
assets of any type as well as a more detailed discussion of the Purchaser's
experience in, and procedures for, the servicing function it will perform under
the Agreement; information regarding the size, composition and growth of the
Purchaser's portfolio of residential mortgage loans of a type similar to the
Mortgage Loans and information on factors related to the Purchaser that may be
material, in the good faith judgment of the Master Servicer or the Depositor, to
any analysis of the servicing of the Mortgage Loans or the related asset-backed
securities, as applicable, including, without limitation:

            (1) whether any prior securitizations of mortgage loans of a type
      similar to the Mortgage Loans involving the Purchaser have defaulted or
      experienced an early amortization or other performance triggering event
      because of servicing during the three-year period immediately preceding
      the date of engagement of the Purchaser;

            (2) the extent of outsourcing the Purchaser utilizes;

            (3) whether there has been previous disclosure of material
      noncompliance with the applicable servicing criteria with respect to
      securitizations of residential mortgage loans involving the Purchaser as a
      servicer during the three-year period immediately preceding the date of
      engagement of the Purchaser;

            (4) whether the Purchaser has been terminated as servicer in a
      residential mortgage loan securitization, either due to a servicing
      default or to application of a servicing performance test or trigger; and

            (5) such other information as the Master Servicer or the Depositor
      may reasonably request for the purpose of compliance with Item 1108(b)(2)
      of Regulation AB;

      (C) a description of any material changes during the three-year period
immediately preceding the date of engagement of the Purchaser to the Purchaser's
policies or procedures with respect to the servicing function it will perform
under the Agreement for mortgage loans of a type similar to the Mortgage Loans;

      (D) information regarding the Purchaser's financial condition, to the
extent that there is a material risk that an adverse financial event or
circumstance involving the Purchaser could have a material adverse effect on the
performance by the Purchaser of its servicing obligations under the Agreement;

      (E) information regarding advances made by the Purchaser on the Mortgage
Loans and the Purchaser's overall servicing portfolio of residential mortgage
loans for the three-year period immediately preceding the date of engagement of
the Purchaser, which may be limited to a statement by an authorized officer of
the Purchaser to the effect that the Purchaser has made all advances required to
be made on residential mortgage loans serviced by it during such period, or, if
such statement would not be accurate, information regarding the percentage and
type of advances not made as required, and the reasons for such failure to
advance;

      (F) a description of the Purchaser's processes and procedures designed to
address any special or unique factors involved in servicing loans of a similar
type as the Mortgage Loans;

      (G) a description of the Purchaser's processes for handling delinquencies,
losses, bankruptcies and recoveries, such as through liquidation of mortgaged
properties, sale of defaulted mortgage loans or workouts; and

      (H) information as to how the Purchaser defines or determines
delinquencies and charge-offs, including the effect of any grace period,
re-aging, restructuring, partial payments considered current or other practices
with respect to delinquency and loss experience.


<PAGE>

                                    EXHIBIT N

                FORM OF INITIAL CERTIFICATION OF THE CUSTODIAN

                                 March 30, 2006

Wells Fargo Asset Securities Corporation
7430 New Technology Way
Frederick, Maryland  21703

Wells Fargo Bank, N.A.
9062 Old Annapolis Road
Columbia, Maryland 21045-1951

Attn: Corporate Trust Services WFMBS 2006-4

      Re:   The Pooling and  Servicing  Agreement,  dated March 30, 2006,
            among   Wells   Fargo  Asset   Securities   Corporation,   as
            Depositor,  Wells Fargo Bank, N.A., as Master  Servicer,  and
            U.S. Bank National Association,  as Trustee,  relating to the
            Wells   Fargo   Asset   Securities   Corporation;    Mortgage
            Pass-Through Certificates, Series 2006-4.

Ladies and Gentlemen:

      In accordance with the provisions of Section 2.02 of the above-referenced
Pooling and Servicing Agreement (the "Pooling and Servicing Agreement"), the
undersigned, as Custodian on behalf of the Trustee, hereby certifies that,
except as specified in any list of exceptions attached hereto, it has received
the original Mortgage Note relating to each of the Mortgage Loans listed on the
Mortgage Loan Schedule.

      The Custodian has made no independent examination of any documents
contained in each Mortgage File beyond the review specifically required in the
Pooling and Servicing Agreement in connection with this initial certification.
The Custodian makes no representations as to: (i) the validity, legality,
sufficiency, enforceability, recordability or genuineness of any of the
documents contained in each Mortgage File or any of the Mortgage Loans
identified in the Mortgage Loan Schedule or (ii) the collectibility,
insurability, effectiveness or suitability of any such Mortgage Loan.


<PAGE>


      Capitalized terms used but not defined herein shall have the meanings
ascribed to such terms in the Pooling and Servicing Agreement.

                                    WELLS FARGO BANK, N.A.,
                                      as Custodian on behalf of the Trustee

                                       By:
                                           -----------------------------
                                      Name:
                                           -----------------------------
                                     Title:
                                           -----------------------------


<PAGE>


                                    EXHIBIT O

                  FORM OF FINAL CERTIFICATION OF THE CUSTODIAN

                            [__________ __, ____]


Wells Fargo Asset Securities Corporation
7430 New Technology Way
Frederick, Maryland  21703

Wells Fargo Bank, N.A.
9062 Old Annapolis Road
Columbia, Maryland 21045-1951

Attn: Corporate Trust Services WFMBS 2006-4

      Re:   The Pooling and Servicing  Agreement,  dated March 30, 2006,
            among   Wells  Fargo  Asset   Securities   Corporation,   as
            Depositor,  Wells Fargo Bank, N.A., as Master Servicer,  and
            U.S. Bank National Association,  as Trustee, relating to the
            Wells   Fargo   Asset   Securities   Corporation;   Mortgage
            Pass-Through Certificates, Series 2006-4.

Ladies and Gentlemen:

      In accordance with the provisions of Section 2.02 of the above-referenced
Pooling and Servicing Agreement (the "Pooling and Servicing Agreement"), the
undersigned, as Custodian on behalf of the Trustee, hereby certifies that, as to
each Mortgage Loan listed in the Mortgage Loan Schedule, except as may be
specified in any list of exceptions attached hereto, such Mortgage File contains
all of the items required to be delivered pursuant to Section 2.01 of the
Pooling and Servicing Agreement.

      The Custodian has made no independent examination of any documents
contained in each Mortgage File beyond the review specifically required in the
Pooling and Servicing Agreement in connection with this final certification. The
Custodian makes no representations as to: (i) the validity, legality,
sufficiency, enforceability, recordability or genuineness of any of the
documents contained in each Mortgage File or any of the Mortgage Loans
identified in the Mortgage Loan Schedule or (ii) the collectibility,
insurability, effectiveness or suitability of any such Mortgage Loan.


<PAGE>


      Capitalized terms used but not defined herein shall have the meanings
ascribed to such terms in the Pooling and Servicing Agreement.

                                    WELLS FARGO BANK, N.A.,
                                      as Custodian on behalf of the Trustee

                                       By:
                                           -----------------------------
                                      Name:
                                           -----------------------------
                                     Title:
                                           -----------------------------


<PAGE>

                                    EXHIBIT P

                      FORM OF SARBANES-OXLEY CERTIFICATION

                   Wells Fargo Asset Securities Corporation
                       Mortgage Pass-Through Certificates,
                                  Series 2006-4

      I, [________], certify that:

      1. I have reviewed this report on Form 10-K and all reports on Form 10-D
required to be filed in respect of the period covered by this report on Form
10-K of the Wells Fargo Asset Securities Corporation, Mortgage Pass-Through
Certificates, Series 2006-4 Trust (the "Exchange Act Periodic Reports");

      2. Based on my knowledge, the Exchange Act Periodic Reports, taken as a
whole, do not contain any untrue statement of a material fact or omit to state a
material fact necessary to make the statements made, in light of the
circumstances under which such statements were made, not misleading with respect
to the period covered by this report;

      3. Based on my knowledge, all of the distribution, servicing and other
information required to be provided under Form 10-D for the period covered by
this report is included in the Exchange Act Periodic Reports;

      4. I am responsible for reviewing the activities performed by the Master
Servicer and based upon my knowledge and the compliance review conducted in
preparing the servicer compliance statement required in this report under Item
1123 of Regulation AB, and except as disclosed in the Exchange Act Periodic
Reports, the Master Servicer has fulfilled its obligations under the pooling and
servicing agreement, dated March 30, 2006, among Wells Fargo Asset Securities
Corporation, as depositor, Wells Fargo Bank, N.A., as master servicer, and U.S.
Bank National Association, as trustee; and

      5. All of the reports on assessment of compliance with the servicing
criteria for asset-backed securities and their related attestation reports on
assessment of compliance with servicing criteria for asset-backed securities
required to be included in this report in accordance with Item 1122 of
Regulation AB and Exchange Act Rules 13a-18 and 15d-18 have been included as an
exhibit to this report, except as otherwise disclosed in this report. Any
material instances of noncompliance described in such reports have been
disclosed in this report on Form 10-K.

      [The following is included only for a transaction where there are
Servicers other than Wells Fargo Bank: In giving the certifications above, I
have reasonably relied on information provided to me by the following
unaffiliated parties: [Name of Servicers other than Wells Fargo Bank], as
Servicer.]

Date: [_____]

                                       By:
                                           -----------------------------
                                      Name:
                                           -----------------------------
                                     Title:
                                           -----------------------------
<PAGE>

                                    EXHIBIT Q

                    SCHEDULE OF PLEDGED ASSET MORTGAGE LOANS


WFMBS
WFMBS 2006-04
F30 YEAR FIXED RATE NON RELOCATION

<TABLE>
<CAPTION>
(i)          (ii)                    (iii)      (iv)       (v)        (vi)        (vii)      (viii)      (ix)          (x)
-----        -----    -----   ----   --------   --------   --------   ---------   --------   ---------   ---------     -----
                                                           NET                                           CUT-OFF
MORTGAGE                                        MORTGAGE   MORTGAGE               ORIGINAL   SCHEDULED   DATE
LOAN                          ZIP    PROPERTY   INTEREST   INTEREST   MONTHLY     TERM TO    MATURITY    PRINCIPAL
NUMBER       CITY     STATE   CODE   TYPE       RATE       RATE       PAYMENT     MATURITY   DATE        BALANCE       LTV
-----        -----    -----   ----   --------   --------   --------   ---------   --------   ---------   ---------     -----
<S>          <C>      <C>     <C>    <C>           <C>        <C>     <C>              <C>   <C>         <C>           <C>
0059708446   NEWTON   MA      2458   SFD           5.875      5.615   $3,794.27        360   1-Dec-35    $775,000.00   79.16

                                                                                                         $775,000.00

<CAPTION>

(i)          (xi)      (xii)       (xiii)             (xiv)      (xv)
-----        -------   --------    --------------     --------   --------

MORTGAGE               MORTGAGE                       MASTER     FIXED
LOAN                   INSURANCE   SERVICE            SERVICE    RETAINED
NUMBER       SUBSIDY   CODE        FEE                FEE        YIELD
-----        -------   --------    ----------------   --------   --------
<S>          <C>       <C>                    <C>        <C>     <C>
0059708446                                    0.250      0.010   0.000
</TABLE>


COUNT:            1
WAC:              5.875
WALTV:            79.16
WAM:              177


<PAGE>


                                    EXHIBIT R

        Servicing Criteria to be Addressed in Assessment of Compliance
<TABLE>
<CAPTION>

---------------------------------------------------------------------------------------------------
                             SERVICING CRITERIA                  APPLICABLE SERVICING CRITERIA
---------------------------------------------------------------------------------------------------
                                                                Master
  Reference                        Criteria                    Servicer Trustee Servicer Custondian
------------------------------------------------------------------------------------------------------
                          General Servicing Considerations
---------------------------------------------------------------------------------------------------
<C>             <C>                                                <C>      <C>    <C>    <C>
1122(d)(1)(i)   Policies and procedures are instituted to          X              X
                monitor any performance or other triggers and
                events of default in accordance with the
                transaction agreements.
---------------------------------------------------------------------------------------------------
1122(d)(1)(ii)  If any material servicing activities are           X              X
                outsourced to third parties, policies and
                procedures are instituted to monitor the third
                party's performance and compliance with such
                servicing activities.
---------------------------------------------------------------------------------------------------
1122(d)(1)(iii) Any requirements in the transaction agreements
                to maintain a back-up servicer for the mortgage
                loans are maintained.
---------------------------------------------------------------------------------------------------
1122(d)(1)(iv)  A fidelity bond and errors and omissions           X              X       X
                policy is in effect on the party participating
                in the servicing function throughout the
                reporting period in the amount of coverage
                required by and otherwise in accordance with
                the terms of the transaction agreements.
---------------------------------------------------------------------------------------------------
                         Cash Collection and Administration
---------------------------------------------------------------------------------------------------
1122(d)(2)(i)   Payments on mortgage loans are deposited into      X              X
                the appropriate custodial bank accounts and
                related bank clearing accounts no more than
                two business days following receipt, or such
                other number of days specified in the
                transaction agreements.
---------------------------------------------------------------------------------------------------
1122(d)(2)(ii)  Disbursements made via wire transfer on behalf     X              X
                of an obligor or to an investor are made only
                by authorized personnel.
---------------------------------------------------------------------------------------------------
1122(d)(2)(iii  Advances of funds or guarantees regarding          X     X(1)     X
                collections, cash flows or distributions,
                and any interest or other fees charged for such
                advances, are made, reviewed and approved as
                specified in the transaction agreements.
---------------------------------------------------------------------------------------------------
                The related accounts for the transaction, such
                as cash reserve accounts or accounts
                established as a form of
                overcollateralization, are separately              X              X
                maintained (e.g., with respect to commingling
                of cash) as set forth in the transaction
1122(d)(2)(iv)  agreements.
---------------------------------------------------------------------------------------------------
1122(d)(2)(v)   Each custodial account is maintained at a          X              X
                federally insured depository institution as
                set forth in the transaction agreements. For
                purposes of this criterion, "federally insured
                depository institution" with respect to a
                foreign financial institution means a foreign
                financial institution that meets the
                requirements of Rule 13k-1(b)(1) of the
                Securities Exchange Act.
---------------------------------------------------------------------------------------------------
1122(d)(2)(vi)  Unissued checks are safeguarded so as to           X              X
                prevent unauthorized access.
---------------------------------------------------------------------------------------------------
1122(d)(2)(vii) Reconciliations are prepared on a monthly          X              X
                basis for all asset-backed securities related
                bank accounts, including custodial accounts
                and related bank clearing accounts. These
                reconciliations are (A) mathematically
                accurate; (B) prepared within 30 calendar days
                after the bank statement cutoff date, or such
                other number of days specified in the
                transaction agreements; (C) reviewed and
                approved by someone other than the person who
                prepared the reconciliation; and (D) contain
                explanations for reconciling items. These
                reconciling items are resolved within 90
                calendar days of their original
                identification, or such other number of days
                specified in the transaction agreements.
---------------------------------------------------------------------------------------------------
                         Investor Remittances and Reporting
---------------------------------------------------------------------------------------------------
1122(d)(3)(i)   Reports to investors, including those to be        X              X
                filed with the Commission, are maintained in
                accordance with the transaction agreements and
                applicable Commission requirements.
                Specifically, such reports (A) are prepared in
                accordance with timeframes and other terms set
                forth in the transaction agreements; (B) provide
                information calculated in accordance with
                the terms specified in the transaction agreements;
                (C) are filed with the Commission as required by
                its rules and regulations; and (D) agree with
                investors' or the trustee's records as to the total
                unpaid principal balance and number of mortgage loans
                serviced by the Servicer.
---------------------------------------------------------------------------------------------------
1122(d)(3)(ii)  Amounts due to investors are allocated and         X              X
                remitted in accordance with timeframes,
                distribution priority and other terms
                set forth in the transaction agreements.
---------------------------------------------------------------------------------------------------
1122(d)(3)(iii) Disbursements made to an investor are posted
                within two business days to the Servicer's
                investor records, or such other number of days     X              X
                specified in the transaction agreements.
---------------------------------------------------------------------------------------------------
1122(d)(3)(iv)  Amounts remitted to investors per the investor
                reports agree with cancelled checks, or other      X              X
                form of payment, or custodial bank statements.
---------------------------------------------------------------------------------------------------
                              Pool Asset Administration
---------------------------------------------------------------------------------------------------
1122(d)(4)(i)   Collateral or security on mortgage loans is        X              X       X
                maintained as required by the transaction
                agreements or related mortgage loan documents.
---------------------------------------------------------------------------------------------------
1122(d)(4)(ii)  Mortgage loan and related documents are
                safeguarded as required by the transaction                        X       X
                agreements
---------------------------------------------------------------------------------------------------
1122(d)(4)(iii) Any additions, removals or substitutions to        X              X
                the asset pool are
                made, reviewed and approved in accordance with
                any conditions or requirements in the
                transaction agreements.
---------------------------------------------------------------------------------------------------
1122(d)(4)(iv)  Payments on mortgage loans, including any                         X
                payoffs, made in accordance with the related
                mortgage loan documents are posted to the
                Servicer's obligor records maintained no more
                than two business days after receipt, or such
                other number of days specified in the
                transaction agreements, and allocated to
                principal, interest or other items (e.g.,
                escrow) in accordance with the related mortgage loan documents.
---------------------------------------------------------------------------------------------------
1122(d)(4)(v)   The Servicer's records regarding the mortgage                     X
                loans agree with the Servicer's records with
                respect to an obligor's unpaid principal
                balance.
---------------------------------------------------------------------------------------------------
1122(d)(4)(vi)  Changes with respect to the terms or status of     X              X
                an obligor's mortgage loans (e.g., loan
                modifications or re-agings) are made, reviewed
                and approved by authorized personnel in
                accordance with the transaction agreements and
                related pool asset documents.
---------------------------------------------------------------------------------------------------
1122(d)(4)(vii) Loss mitigation or recovery actions (e.g.,         X              X
                forbearance plans, modifications and deeds in
                lieu of foreclosure, foreclosures and
                repossessions, as applicable) are initiated,
                conducted and concluded in accordance with the
                timeframes or other requirements established
                by the transaction agreements.
---------------------------------------------------------------------------------------------------
1122(d)(4)(viii)Records documenting collection efforts are                        X
                maintained during the period a mortgage loan is
                delinquent in accordance with the transaction
                agreements. Such records are maintained on at
                least a monthly basis, or such other period
                specified in the transaction agreements, and
                describe the entity's activities in monitoring
                delinquent mortgage loans including, for
                example, phone calls, letters and payment
                rescheduling plans in cases where delinquency
                is deemed temporary (e.g., illness or
                unemployment).
---------------------------------------------------------------------------------------------------
1122(d)(4)(ix)  Adjustments to interest rates or rates of                         X
                return for mortgage loans with variable
                rates are computed based on the related
                mortgage loan documents.
---------------------------------------------------------------------------------------------------
1122(d)(4)(x)   Regarding any funds held in trust for an                          X
                obligor (such as escrow accounts): (A) such
                funds are analyzed, in accordance with the
                obligor's mortgage loan documents, on at least
                an annual basis, or such other period
                specified in the transaction agreements; (B)
                interest on such funds is paid, or credited,
                to obligors in accordance with applicable
                mortgage loan documents and state laws; and
                (C) such funds are returned to the obligor
                within 30 calendar days of full repayment of
                the related mortgage loans, or such other
                number of days specified in the transaction
                agreements.
---------------------------------------------------------------------------------------------------
1122(d)(4)(xi)  Payments made on behalf of an obligor (such as                    X
                tax or insurance payments) are made on or
                before the related penalty or expiration
                dates, as indicated on the appropriate bills
                or notices for such payments, provided that
                such support has been received by the servicer
                at least 30 calendar days prior to these
                dates, or such other number of days specified
                in the transaction agreements.
---------------------------------------------------------------------------------------------------
1122(d)(4)(xii) Any late payment penalties in connection with                    X
                any payment to be made on behalf of an obligor
                are paid from the Servicer's funds and not charged
                to the obligor, unless the late payment was due to
                the obligor's error or omission.
---------------------------------------------------------------------------------------------------
1122(d)(4)(xiii)Disbursements made on behalf of an obligor are
                posted within two business days to the
                obligor's records maintained by the Servicer,                   X
                or such other number of days specified in the
                transaction agreements.
---------------------------------------------------------------------------------------------------
1122(d)(4)(xiv) Delinquencies, charge-offs and uncollectible      X              X
                accounts are recognized and recorded in
                accordance with the transaction agreements.
---------------------------------------------------------------------------------------------------
1122(d)(4)(xv)  Any external enhancement or other support,
                identified in Item 1114(a)(1) through (3)         X
                or Item 1115 of Regulation AB, is maintained
                as set forth in the transaction agreements.
---------------------------------------------------------------------------------------------------
</TABLE>


[-----------------------]


Date: _________________________

By:_____________________________
   Name:
   Title:

(1)   This Servicing Criterion applies to the Trustee if the Trustee was
      required during the preceding calendar year to make an Advance in
      accordance with Section 8.14 of the Pooling and Servicing Agreement.

<PAGE>
                                    EXHIBIT S

                         Additional Form 10-D Disclosure

-------------------------------------------------------------------------------
Item on Form 10-D                           Party Responsible
-------------------------------------------------------------------------------
Item 1: Distribution and Pool               Master Servicer, Depositor
       Performance Information

      Any information required by 1121
      which is NOT included on the
      Distribution Date Statement
-------------------------------------------------------------------------------
Item 2: Legal Proceedings per Item          (i) All parties to the Pooling
      1117 of Reg AB                        and Servicing Agreement, the
                                            Custodian, each Servicer and, if
                                            applicable the Special Servicer (as
                                            to themselves), (ii) the Master
                                            Servicer as to the issuing entity,
                                            (iii) the Depositor as to the
                                            sponsor, any 1110(b) originator, any
                                            1100(d)(1) party
-------------------------------------------------------------------------------
Item 3: Sale of Securities and Use of       Depositor
       Proceeds
-------------------------------------------------------------------------------
Item 4: Defaults Upon Senior Securities     Master Servicer
-------------------------------------------------------------------------------
Item 5: Submission of Matters to a          Master Servicer, Trustee
       Vote of Security Holders
-------------------------------------------------------------------------------
Item 6: Significant Obligors of Pool        Depositor, if applicable
       Assets
-------------------------------------------------------------------------------
Item 7: Significant Enhancement             Depositor, if applicable
       Provider Information
-------------------------------------------------------------------------------
Item 8: Other Information                   Any party responsible for
                                            disclosure items on Form 8-K
-------------------------------------------------------------------------------
Item 9: Exhibits                            Depositor, Master Servicer
-------------------------------------------------------------------------------

<PAGE>

                                    EXHIBIT T

                         Additional Form 10-K Disclosure

-------------------------------------------------------------------------------
Item on Form 10-K                            Party Responsible
-------------------------------------------------------------------------------
Item 1B: Unresolved Staff Comments           Depositor
-------------------------------------------------------------------------------
Item 9B:  Other Information                  Any party responsible for
                                             disclosure items on Form 8-K
-------------------------------------------------------------------------------
Item 15: Exhibits, Financial Statement       Master Servicer
       Schedules                             Depositor
-------------------------------------------------------------------------------
Additional Item:                             (i) All parties to the Pooling
                                             and Servicing Agreement, the
Disclosure per Item 1117 of Reg AB           Custodian, each Servicer and, if
                                             applicable the Special Servicer
                                             (as to themselves), (ii) the
                                             Master Servicer as to the
                                             issuing entity, (iii) the
                                             Depositor as to the sponsor, any
                                             1110(b) originator, any
                                             1100(d)(1) party
-------------------------------------------------------------------------------
Additional Item:                             (i) All parties to the Pooling
Disclosure per Item 1119 of Reg AB           and Servicing Agreement, the
                                             Custodian, each Servicer and, if
                                             applicable the Special Servicer (as
                                             to themselves), (ii) the Master
                                             Servicer as to the issuing entity,
                                             (iii) the Depositor as to the
                                             sponsor, any 1110(b) originator,
                                             any 1100(d)(1) party, any
                                             significant obligor, any credit
                                             enhancement provider or derivative
                                             counterparty
-------------------------------------------------------------------------------
Additional Item:                             Depositor, if applicable
Disclosure per Item 1112(b) of Reg AB
-------------------------------------------------------------------------------
Additional Item:                             Depositor, if applicable
Disclosure per Items 1114(b) and
1115(b) of Reg AB
-------------------------------------------------------------------------------

<PAGE>

                                    EXHIBIT U

                         Form 8-K Disclosure Information

-------------------------------------------------------------------------------
Item on Form 8-K                             Party Responsible
-------------------------------------------------------------------------------
Item 1.01- Entry into a Material             All parties to the Pooling and
         Definitive                          Agreement Servicing Agreement, each
                                             Servicer, the Custodian and, if
                                             applicable, the Special Servicer,
                                             as to each agreement to which it is
                                             a party
-------------------------------------------------------------------------------
Item 1.02- Termination of a Material         All parties to the Pooling and
         Definitive                          Agreement Servicing Agreement, each
                                             Servicer, the Custodian and, if
                                             applicable, the Special Servicer,
                                             as to each agreement to which it is
                                             a party
-------------------------------------------------------------------------------
Item 1.03- Bankruptcy or Receivership        (i) Depositor, as to itself, the
                                             sponsor, any 1100(d)(1) party,
                                             any significant obligor, any
                                             credit enhancement provider or
                                             derivative counterparty and any
                                             other transaction party, to the
                                             extent known to the Depositor,
                                             (ii) Trustee, as to itself,
                                             (iii) each Servicer as to
                                             itself, (iv) Master Servicer, as
                                             to itself and any other
                                             transaction party, to the extent
                                             known to the Master Servicer
-------------------------------------------------------------------------------
Item 2.04- Triggering Events that            Master Servicer
         Accelerate or Increase a
         Direct Financial Obligation
         or an Obligation under an
         Off-Balance Sheet Arrangement
-------------------------------------------------------------------------------
Item 3.03- Material Modification to          Master Servicer
         Rights of Security Holders
-------------------------------------------------------------------------------
Item 5.03- Amendments of Articles of         Master Servicer
         Incorporation or Bylaws;
         Change of Fiscal Year
-------------------------------------------------------------------------------
Item 6.01- ABS Informational and             Depositor
         Computational Material
-------------------------------------------------------------------------------
Item 6.02- Change of Servicer or             Servicer, Master Servicer
         Master Servicer
-------------------------------------------------------------------------------
Item 6.03- Change in Credit                  Depositor/Master Servicer
         Enhancement or External
         Support
-------------------------------------------------------------------------------
Item 6.04- Failure to Make a Required        Master Servicer
         Distribution
-------------------------------------------------------------------------------
Item 6.05- Securities Act Updating           Depositor
         Disclosure
-------------------------------------------------------------------------------
Item 7.01- Reg FD Disclosure                 Depositor
-------------------------------------------------------------------------------
Item 8.01-Other Events                       Depositor, Master Servicer
-------------------------------------------------------------------------------
Item 9.01                                    Depositor, Master Servicer
-------------------------------------------------------------------------------


<PAGE>

                                    EXHIBIT V

                       Additional Disclosure Notification

**SEND VIA FAX TO 410-715-2380 AND VIA EMAIL TO
CTS.SEC.NOTIFICATIONS@WELLSFARGO.COM AND VIA OVERNIGHT MAIL TO THE ADDRESS
IMMEDIATELY BELOW**

Wells Fargo Bank, N.A., as Master Servicer
Old Annapolis Road
Columbia, Maryland 21045
Attn: Corporate Trust Services- WFMBS 2006-4--SEC REPORT PROCESSING

RE:**[Additional Form [10-D][10-K] Disclosure][Form 8-K Disclosure
Information]** Required


Ladies and Gentlemen:

            In accordance with Section [ ] of the Pooling and Servicing
Agreement, dated as of March 30, 2006, among Wells Fargo Asset Securities
Corporation, as depositor, Wells Fargo Bank, N.A., as master servicer, and U.S.
Bank National Association, as trustee, the undersigned, as [ ], hereby notifies
you that certain events have come to our attention that [will] [may] need to be
disclosed on Form [10-D][10-K][8-K].

Description of [Additional Form [10-D][10-K]  Disclosure][Form 8-K Disclosure
Information]:





List of any Attachments hereto to be included in the Additional Form
[10-D][10-K] Disclosure][Form 8-K Disclosure Information]:

            Any inquiries related to this  notification  should be directed to
[      ],       phone       number:       [      ];       email       address:
[                   ].



                                                [NAME OF PARTY],
                                                as [role]


                                                By: __________________________
                                                    Name:
                                                    Title:


<PAGE>

                                   EXHIBIT W

                          Yield Maintenance Agreement



                   [LETTERHEAD OF THE ROYAL BANK OF SCOTLAND]


Memorandum                                                        March 30, 2006

To                  Wells Fargo Bank, N.A. as master servicer on behalf of the
                    Trust (such trust, the "Issuing Entity") created under the
                    Pooling and Servicing Agreement (as defined below)

Address             Wells Fargo Bank, N.A.
                    9062 Old Annapolis Road
                    Columbia, Maryland 21045

Attention           Client Manager - Wells Fargo Mortgage Backed Securities,
                    Series 2006-4
                    Telephone: 410-884-2000
                    Facsimile:  410-715-2380

CC:                 Greenwich Capital Markets, Inc.

Address             600 Steamboat Road
                    Greenwich, CT 06830

From:               The Royal Bank of Scotland plc


Address             280 Bishopsgate
                    London EC2M 4RB

Attention           Legal Department - Derivatives Documentation
                    Telephone: (203) 618-2531/2532
                    Facsimile: (203) 618-2533/2534

Reference Numbers   IRG6951079.2A.2B


Dear Sir/Madam,

The purpose of this letter agreement is to confirm the terms and conditions of
the transaction entered into between Wells Fargo Bank, N.A. as master servicer
(the "Master Servicer") under the Pooling and Servicing Agreement (as defined
below) on behalf of the Issuing Entity and The Royal Bank of Scotland plc,
acting through its agent, Greenwich Capital Markets, Inc. (each a "party" and
together "the parties") on the Trade Date specified below (the "Transaction").
This letter agreement constitutes a "Confirmation" as referred to in the ISDA
Master Agreement specified in paragraph 1 below. In this Confirmation, "Party A"
means The Royal Bank of Scotland plc, acting through its agent, Greenwich
Capital Markets, Inc., and "Party B" means Wells Fargo Bank, N.A. as Master
Servicer on behalf of the Issuing Entity.

The definitions and provisions contained in the 2000 ISDA Definitions, as
published by the International Swaps and Derivatives Association, Inc. (the
"Definitions"), are incorporated into this Confirmation. In the event of any
inconsistency between the Definitions and this Confirmation, this Confirmation
will govern.

Other capitalized terms used herein (but not otherwise defined) shall have the
meaning specified in that certain Pooling and Servicing Agreement (the "Pooling
and Servicing Agreement"), to be dated as of March 30, 2006, among Wells Fargo
Asset Securities Corporation, as depositor (the "Depositor"), Wells Fargo Bank,
N.A., as Master Servicer and U.S. Bank National Association, as trustee.

1      This Confirmation evidences a complete binding agreement between the
       parties as to the terms of the Transaction to which this Confirmation
       relates. In addition, the parties agree that for the purposes of this
       Transaction, this Confirmation will supplement, form a part of, and be
       subject to an agreement in the form of the 1992 ISDA Master Agreement
       (Multicurrency-Cross Border) as if the parties had executed an agreement
       in such form (but without any Schedule except for the elections noted
       below) on the Trade Date of the Transaction (such agreement, the "Form
       Master Agreement"). In the event of any inconsistency between the
       provisions of the Form Master Agreement and this Confirmation, this
       Confirmation will prevail for the purpose of this Transaction.

       Each party represents to the other party and will be deemed to represent
       to the other party on the date on which it enters into this Transaction
       that (absent a written agreement between the parties that expressly
       imposes affirmative obligations to the contrary for that Transaction):

      (a)   Non-Reliance

              Each party has made its own independent decisions to enter into
              this Transaction and as to whether this Transaction is appropriate
              or proper for it based upon its own judgment and upon advice from
              such advisors as it has deemed necessary. It is not relying on any
              communication (written or oral) of the other party as investment
              advice or as a recommendation to enter into this Transaction; it
              being understood that information and explanations related to the
              terms and conditions of this Transaction shall not be considered
              investment advice or a recommendation to enter into this
              Transaction. Further, such party has not received from the other
              party any assurance or guarantee as to the expected results of
              this Transaction.

      (b)   Evaluation and Understanding

              It is capable of evaluating and understanding (on its own behalf
              or through independent professional advice), and understands and
              accepts, the terms, conditions and risks of this Transaction. It
              is also capable of assuming, and assumes, the financial and other
              risks of this Transaction.

      (c)   Status of Parties

              The other party is not acting as an agent, fiduciary or advisor
              for it in respect of this Transaction.

2     The terms of the particular Transaction to which this Confirmation relates
      are as follows:



Notional Amount:                    With respect to any Calculation Period, the
                                    lesser of (i) the amount set forth on
                                    Schedule A attached hereto and (ii) the
                                    aggregate Certificate Principal Balance of
                                    the Class I-A-5 Certificates on the monthly
                                    statement from the Master Servicer for the
                                    distribution occurring on the first day of
                                    the applicable Calculation Period.

                                    The Master Servicer shall make available
                                    each month via its website a statement
                                    containing the Class Certificate Principal
                                    Balance of the Class I-A-5 Certificates as
                                    of the first day of such Calculation Period.
                                    Party A is permitted to rely upon the
                                    statement of Class Certificate Principal
                                    Balance of the Class I-A-5 Certificates made
                                    available on the Master Servicer's website.
                                    The Master Servicer's internet website shall
                                    initially be located at www.ctslink.com and
                                    assistance in using the website can be
                                    obtained by calling the Master Servicer's
                                    investor relations desk at (301) 815-6600.

                                    Any payment by Party A to Party B in excess
                                    of the amount due under this Transaction on
                                    any Floating Rate Payer Payment Date shall
                                    be returned by Party B to Party A promptly
                                    after notification from Party B that Party B
                                    is aware of such overpayment. Other than the
                                    return of such overpayment, neither Party A
                                    nor Party B shall incur any penalty or
                                    liability hereunder with respect to such
                                    overpayment.

Trade Date:                         March 9, 2006

Effective Date:                     March 30, 2006

Termination Date:                   December 25, 2021

Fixed Amounts:

Fixed Rate Payer:                   Party B

Fixed Rate Payer Payment Date:      March 30, 2006

Fixed Amount:                       USD [       ]

Floating Amounts:

Floating Rate Payer:                Party A

Cap Rate:                           5.05%

Floating Rate Payer Period
End Dates:                          The 25th day of each month of each year,
                                    commencing on April 25, 2006, through and
                                    including the Termination Date, subject to
                                    no adjustment.

Floating Rate Payer Payment Dates:  Early Payment shall be applicable. The
                                    Floating Rate Payer Payment Date shall be
                                    one Business Day prior to each Floating Rate
                                    Payer Period End Date.



Floating Rate for Initial
Calculation Period:                 To be determined.

Floating Rate Option:               USD-LIBOR-BBA; provided,
                                    however, if the Floating Rate Option for
                                    any Calculation Period is greater than
                                    8.80% then the Floating Rate Option for
                                    such Calculation Period shall be deemed to
                                    be 8.80%.

Floating Amount:                    To be determined in accordance with the
                                    following formula: the greater of (i)
                                    (Floating Rate Option - Cap Rate) * Notional
                                    Amount * Floating Rate Day Count Fraction
                                    and (ii) zero.

Designated Maturity:                1 Month

Spread:                             None

Floating Rate Day Count Fraction:   30/360


Reset Dates:                        The first day of each Calculation Period.

Business Days for Payments:         New York

Calculation Agent:                  Party A; provided, however, that if an Event
                                    of Default occurs with respect to Party A,
                                    then Party B shall be entitled to appoint a
                                    financial institution which would qualify as
                                    a Reference Market-Maker to act as
                                    Calculation Agent (such financial
                                    institution subject to Party A's consent).

3     Form Master Agreement

      (a)   "Specified Entity" means, in relation to Party A, for the purpose of
            Section 5(a)(v), Section 5(a)(vi), Section 5(a)(vii) and Section
            5(b)(iv): Not Applicable.

      (b)   "Specified Entity" means, in relation to Party B, for the purpose of
            Section 5(a)(v), Section 5(a)(vi), Section 5(a)(vii) and Section
            5(b)(iv): Not Applicable.

      (c)   "Specified Transaction" is not applicable to Party A or Party B for
            any purpose, and accordingly, Section 5(a)(v) shall not apply to
            Party A or Party B.

      (d)   The "Cross Default" provisions of Section 5(a)(vi) will not apply to
            Party A or Party B.

      (e)   The "Credit Event Upon Merger" provisions of Section 5(b)(iv) of the
            Form Master Agreement will not apply to Party A or to Party B.

      (f)   The "Automatic Early Termination" provision of Section 6(a) of the
            Form Master Agreement will not apply to Party A or to Party B.

      (g)   The Form Master Agreement will be governed by, and construed in
            accordance with, the laws of the State of New York without reference
            to its conflict of laws provisions (except for Sections 5-1401 and
            5-1402 of the New York General Obligations Law).

      (h)   The phrase "Termination Currency" means United States Dollars.

      (i)   For the purpose of Section 6(e) of the Form Master Agreement, Market
            Quotation and Second Method will apply.

4     Recording of Conversations

      Each party to this Transaction acknowledges and agrees to the tape (and/or
      other electronic) recording of conversations between the parties to this
      Transaction whether by one or other or both of the parties or their
      agents.

5     Credit Support Document

      In relation to Party A:   Not Applicable.

      In relation to Party B:   Not Applicable.

6     Credit Support Provider

      In relation to Party A:   Not Applicable.

      In relation to Party B:   Not Applicable.

7     Account Details

      Account for payments to Party A:

              USD
              For the account of The Royal Bank of Scotland Financial Markets
              Fixed Income and Interest Rate Derivative Operations, London SWIFT
              RBOSGB2RTCM with JPMorgan Chase Bank, New York CHASUS33 Account
              Number 400930153/ABA 021000021

      Account for payments to Party B: [TO BE CONFIRMED]

              Wells Fargo Bank, N.A.

              ABA #:          121000248
              Account Name:   SAS Clearing
              ACCT #:         3970771416
              FCC to:         50907801, Reference WFMBS 2006-4 Reserve Account

8     Offices

      The Office of Party A for this Transaction is:

              London

      The Office of Party B for this Transaction is:

              Columbia, MD

9     Additional Provisions

      Fully-Paid Transactions

              Notwithstanding the terms of Sections 5 and 6 of the Form Master
              Agreement, if at any time and so long as Party B shall have
              satisfied in full all its payment and delivery obligations under
              Section 2(a)(i) of the Form Master Agreement and shall at the time
              have no future payment or delivery obligations, whether absolute
              or contingent, under such Section, then unless Party A is required
              pursuant to appropriate proceedings to return to Party B or
              otherwise returns to Party B (upon demand of Party B, or
              otherwise) any portion of any such payment or delivery: (i) the
              occurrence of an event described in Section 5(a) of the Form
              Master Agreement with respect to Party B shall not constitute an
              Event of Default or a Potential Event of Default with respect to
              Party B as the Defaulting Party; and (ii) Party A shall be
              entitled to designate an Early Termination Date pursuant to
              Section 6 of the Form Master Agreement only as a result of the
              occurrence of a Termination Event set forth in (i) either Section
              5(b)(i) or 5(b)(ii) of the Form Master Agreement with respect to
              Party A as the Affected Party or (ii) Section 5(b)(iii) of the
              Form Master Agreement with respect to Party A as the Burdened
              Party.

10    Compliance with Regulation AB

      (a)   Party A acknowledges that for so long as there are reporting
            obligations with respect to this Transaction under Regulation AB,
            the Depositor, acting on behalf of the Issuing Entity, is required
            under Regulation AB under the Securities Act of 1933, as amended,
            and the Securities Exchange Act of 1934, as amended ("Regulation
            AB"), to disclose certain information set forth in Regulation AB
            regarding Party A or its group of affiliated entities, if
            applicable, depending on the aggregate "significance percentage" of
            this Agreement and any other derivative contracts between Party A or
            its group of affiliated entities, if applicable, and Party B, as
            calculated from time to time in accordance with Item 1115 of
            Regulation AB.

      (b)   If the Depositor determines, reasonably and in good faith, that the
            significance percentage of this Agreement has increased to nine (9)
            percent or more, then the Depositor may request on a Business Day
            after the date of such determination from Party A the same
            information set forth in Item 1115(b)(1) of Regulation AB that would
            have been required if the significance percentage had in fact
            increased to ten (10) percent, along with any necessary auditors'
            consent (such request, a "10% Cap Disclosure Request" and such
            requested information, subject to the last sentence of this
            paragraph, is the "10% Cap Financial Disclosure"). Party B or the
            Depositor shall provide Party A with the calculations and any other
            information reasonably requested by Party A with respect to the
            Depositor's determination that led to the 10% Cap Disclosure
            Request. The parties hereto further agree that the 10% Cap Financial
            Disclosure provided to meet the 10% Cap Disclosure Request may be,
            solely at Party A's option, either the information set forth in Item
            1115(b)(1) or Item 1115(b)(2) of Regulation AB.

      (c)   Upon the occurrence of a 10% Cap Disclosure Request, Party A, at its
            own expense, shall (i) provide the Depositor with the 10% Cap
            Financial Disclosure, (ii) subject to Rating Agency Confirmation,
            secure another entity to replace Party A as party to this Agreement
            on terms substantially similar to this Agreement which entity is
            able to (A) provide the 10% Cap Financial Disclosure and (B) provide
            an indemnity to the Depositor, reasonably satisfactory to the
            Depositor, in relation to the 10% Cap Financial Disclosure or (iii)
            subject to Rating Agency Confirmation, obtain a guaranty of Party
            A's obligations under this Agreement from an affiliate of Party A
            that is able to provide the 10% Cap Financial Disclosure, such that
            disclosure provided in respect of the affiliate will, in the
            judgment of counsel to the Depositor, satisfy any disclosure
            requirements applicable to Party A, and cause such affiliate to
            provide 10% Cap Financial Disclosure. If permitted by Regulation AB,
            any required 10% Cap Financial Disclosure may be provided by
            incorporation by reference from reports filed pursuant to the
            Securities Exchange Act.

      (d)   If the Depositor determines, reasonably and in good faith, that the
            significance percentage of this Agreement has increased to nineteen
            (19) percent or more, then the Depositor may request on a Business
            Day after the date of such determination from Party A the same
            information set forth in Item 1115(b)(2) of Regulation AB that would
            have been required if the significance percentage had in fact
            increased to twenty (20) percent, along with any necessary auditors
            consent (such request, a "20% Cap Disclosure Request" and such
            requested information is the "20% Cap Financial Disclosure"). Party
            B or the Depositor shall provide Party A with the calculations and
            any other information reasonably requested by Party A with respect
            to the Depositor's determination that led to the 20% Cap Disclosure
            Request.

      (e)   Upon the occurrence of a 20% Cap Disclosure Request, Party A, at its
            own expense, shall (i) provide the Depositor with the 20% Cap
            Financial Disclosure, (ii) subject to Rating Agency Confirmation,
            secure another entity to replace Party A as party to this Agreement
            on terms substantially similar to this Agreement which entity is
            able to (A) provide the 20% Cap Financial Disclosure and (B) provide
            an indemnity to the Depositor, reasonably satisfactory to the
            Depositor, in relation to the 20% Cap Financial Disclosure or (iii)
            subject to Rating Agency Confirmation, obtain a guaranty of Party
            A's obligations under this Agreement from an affiliate of Party A
            that is able to provide the 20% Cap Financial Disclosure, such that
            disclosure provided in respect of the affiliate will, in the
            judgment of counsel to the Depositor, satisfy any disclosure
            requirements applicable to Party A, and cause such affiliate to
            provide 20% Cap Financial Disclosure. If permitted by Regulation AB,
            any required 20% Cap Financial Disclosure may be provided by
            incorporation by reference from reports filed pursuant to the
            Securities Exchange Act.

11    Additional Termination Events

      The following Additional Termination Events will apply:

      (a)   a Ratings Event has occurred and Party A has not, within thirty (30)
            days, complied with Section 12 below, then an Additional Termination
            Event shall have occurred with respect to Party A and Party A shall
            be the sole Affected Party with respect to such Additional
            Termination Event.

      (b)   If (A) the Depositor still has a reporting obligation with respect
            to this Transaction pursuant to Regulation AB and (B) Party A has
            not, within 30 days after receipt of a 10% Cap Disclosure Request
            complied with the provisions set forth in clauses (b) and (c) of
            Paragraph 10 above (provided that if the significance percentage is
            10% or more and less than 20% when the 10% Cap Disclosure Request is
            made or reaches 10% after a 10% Cap Disclosure Request has been made
            to Party A, Party A must comply with the provisions set forth in
            clauses (b) and (c) of Paragraph 10 above within 5 days of Party A
            being informed of the significance percentage reaching 10% or more),
            then an Additional Termination Event shall have occurred with
            respect to Party A and Party A shall be the sole Affected Party with
            respect to such Additional Termination Event.

      (c)   If (A) the Depositor still has a reporting obligation with respect
            to this Transaction pursuant to Regulation AB and (B) Party A has
            not, within 30 days after receipt of a 20% Cap Disclosure Request
            complied with the provisions set forth in clauses (d) and (e) of
            Paragraph 10 above (provided that if the significance percentage is
            20% or more when the 20% Cap Disclosure Request is made or reaches
            20% after a 20%Cap Disclosure Request has been made to Party A,
            Party A must comply with the provisions set forth in clauses (d) and
            (e) of Paragraph 10 above within 5 days of Party A being informed of
            the significance percentage reaching 20% or more), then an
            Additional Termination Event shall have occurred with respect to
            Party A and Party A shall be the sole Affected Party with respect to
            such Additional Termination Event.

12    Ratings Event

      If a Ratings Event (as defined below) occurs with respect to Party A (or
      any applicable Credit Support Provider), then Party A shall, at its own
      expense, (i) assign this Transaction within thirty (30) days of such
      Ratings Event to a third party that meets or exceeds, or as to which any
      applicable credit support provider meets or exceeds, the Approved Ratings
      Thresholds (as defined below) on terms substantially similar to this
      Confirmation, which party is approved by Party B, which approval shall not
      be unreasonably withheld, (ii) obtain a guaranty of, or a contingent
      agreement of, another person with the Approval Rating Thresholds to honor
      Party A's obligations under this Agreement, provided that such other
      person is approved by Party B, such approval not to be unreasonably
      withheld, (iii) post collateral under agreements and other instruments
      satisfactory to Fitch Ratings ("Fitch") and Moody's Investor Service, Inc.
      ("Moody's"), which will be sufficient to restore the immediately prior
      ratings of the Certificates, or (iv) establish any other arrangement
      satisfactory to Fitch and Moody's which will be sufficient to restore the
      immediately prior ratings of the Certificates. For avoidance of doubt, a
      downgrade of the ratings on the Certificates could occur in the event that
      Party A does not post sufficient collateral. For purposes of this
      Transaction, a "Ratings Event" shall occur with respect to Party A (or any
      applicable credit support provider) if its short term unsecured and
      unsubordinated debt rating is withdrawn or reduced below "F1" by Fitch or
      its short-term unsecured unsubordinated debt rating is withdrawn or
      reduced below "P-1" by Moody's (including in connection with a merger,
      consolidation or other similar transaction by Party A or any applicable
      credit support provider) such ratings being referred to herein as the
      "Approved Rating Thresholds," unless, within thirty (30) days hereafter,
      each of Fitch and Moody's has reconfirmed the ratings of the Certificates,
      as applicable, which was in effect immediately prior thereto (such
      confirmation a "Rating Agency Confirmation").

13    Waiver of Right to Trial by Jury

      EACH PARTY HEREBY IRREVOCABLY WAIVES ANY AND ALL RIGHTS TO TRIAL BY JURY
      WITH RESPECT TO ANY LEGAL PROCEEDING ARISING OUT OF OR RELATING TO THIS
      TRANSACTION.

14    Eligible Contract Participant

      Each party represents to the other party that it is an "eligible contract
      participant" as defined in Section 1a(12) of the U.S. Commodity Exchange
      Act, as amended.

15    Notice by Facsimile Transmission

      Section 12(a) is amended by adding in the third line thereof after the
      phrase "messaging system" and before the ")" the words ";provided,
      however, any such notice or other communication may be given by facsimile
      transmission (it being agreed that the burden of proving receipt will be
      on the sender and will not be met by a transmission report generated by
      the sender's facsimile machine)".

16    Multibranch Party

      For purpose of Section 10(c) of the Form Master Agreement: (a) Party A is
      a Multibranch Party; and (b) Party B is not a Multibranch Party.

17    Other provisions

      (d)   Addresses for notices. As set forth on page 1 hereof.

      (e)   For the purpose of Section 13(c) of the Form Master Agreement: (i)
            Party A appoints as its Process Agent, not applicable; and (ii)
            Party B appoints as its Process Agent, not applicable.

      (f)   Section 12(a)(ii) of the Form Master Agreement is deleted in its
            entirety.

      (g)   Documents to be Delivered. For the purpose of Section 4(a) of the
            Form Master Agreement:


<TABLE>
<CAPTION>
  Party required                                                                                Covered by
    to deliver                                                       Date by which             Section 3(d)
     document                   Form/Document/Certificate           to be delivered           Representation
<S>                       <C>                                    <C>                         <C>
Party A and Party B       A certificate of an authorized         Upon the execution          Yes
                          officer of the party, as to the        and delivery of this
                          incumbency and authority of the        Confirmation
                          respective officers of the party
                          signing this Confirmation
</TABLE>


      (h)   Limitation of Liability

            It is expressly understood and agreed by the parties hereto that (a)
            this letter agreement is executed and delivered by the Master
            Servicer, not individually or personally but solely as the Master
            Servicer on behalf of the Issuing Entity, in the exercise of the
            powers and authority conferred and vested in it, (b) the
            representations, undertakings and agreements herein are made on the
            part of Party B and intended not as personal representations,
            undertakings and agreements by the Master Servicer but are made and
            intended for the purpose of binding only Party B, (c) nothing herein
            contained shall be construed as creating any liability on the Master
            Servicer, individually or personally, to perform any covenant either
            expressed or implied contained herein, all such liability, if any,
            being expressly waived by the parties who are signatories to this
            letter agreement and by any person claiming by, through or under
            such parties, and (d) under no circumstances shall the Master
            Servicer be personally liable for the payment of any indebtedness or
            expenses of the Issuing Entity or be liable for the breach or
            failure of any obligation, representation, warranty or covenant made
            or undertaken by Party B under this letter agreement.

      (i)   This letter agreement may be executed in several counterparts, each
            of which shall be deemed an original but all of which together shall
            constitute one and the same instrument.

      (j)   USA PATRIOT Act Notice. Party A hereby notifies Party B that
            pursuant to the requirements of the USA PATRIOT ACT (Title III of
            Pub. L. 107-56 (signed into law October 26, 2001)), as amended (the
            "Act"), it is required to obtain, verify and record information that
            identifies Party B, which information includes the name and address
            of Party B and other information that will allow Party A to identify
            Party B in accordance with the Act.

      (k)   Agency Role of Greenwich Capital Markets, Inc. This Transaction has
            been entered into by Greenwich Capital Markets, Inc., as agent for
            The Royal Bank of Scotland plc. Greenwich Capital Markets, Inc. has
            not guaranteed and is not otherwise responsible for the obligations
            of Party A under this Transaction.

                  [remainder of page intentionally left blank]

<PAGE>


THE ROYAL BANK OF SCOTLAND PLC

By: Greenwich Capital Markets, Inc., its agent


By: ________________________________________

Authorized Signatory




Confirmed as of the date above;

Wells Fargo Bank, N.A., not individually but solely as master servicer under the
Pooling and Servicing Agreement on behalf of Wells Fargo Mortgage Backed
Securities 2006-4 Trust


By   _____________________________________
     Name:
     Title:


<PAGE>


                                   SCHEDULE A

                     Our Reference Numbers: IRG6951079.2A.2B

From and including            To but excluding            Notional Amount (USD)
------------------            ----------------            --------------------
     03/30/06                         04/25/06                   68,000,000.00
     04/25/06                         05/25/06                   67,959,077.32
     05/25/06                         06/25/06                   67,918,106.35
     06/25/06                         07/25/06                   67,576,275.13
     07/25/06                         08/25/06                   66,456,880.10
     08/25/06                         09/25/06                   65,203,552.93
     09/25/06                         10/25/06                   63,819,578.45
     10/25/06                         11/25/06                   62,308,569.87
     11/25/06                         12/25/06                   60,674,459.90
     12/25/06                         01/25/07                   58,921,490.43
     01/25/07                         02/25/07                   57,203,375.03
     02/25/07                         03/25/07                   55,519,623.51
     03/25/07                         04/25/07                   53,869,752.52
     04/25/07                         05/25/07                   52,253,285.40
     05/25/07                         06/25/07                   50,669,752.18
     06/25/07                         07/25/07                   49,118,689.40
     07/25/07                         08/25/07                   47,599,640.06
     08/25/07                         09/25/07                   46,112,153.53
     09/25/07                         10/25/07                   44,655,785.47
     10/25/07                         11/25/07                   43,230,097.71
     11/25/07                         12/25/07                   41,834,658.21
     12/25/07                         01/25/08                   40,469,040.91
     01/25/08                         02/25/08                   39,132,825.74
     02/25/08                         03/25/08                   37,825,598.43
     03/25/08                         04/25/08                   36,546,950.52
     04/25/08                         05/25/08                   35,296,479.25
     05/25/08                         06/25/08                   34,073,787.43
     06/25/08                         07/25/08                   32,878,483.45
     07/25/08                         08/25/08                   31,710,181.13
     08/25/08                         09/25/08                   30,568,499.71
     09/25/08                         10/25/08                   29,453,063.69
     10/25/08                         11/25/08                   28,363,502.85
     11/25/08                         12/25/08                   27,299,452.11
     12/25/08                         01/25/09                   26,260,551.48
     01/25/09                         02/25/09                   25,246,446.00
     02/25/09                         03/25/09                   24,256,785.66
     03/25/09                         04/25/09                   23,291,225.33
     04/25/09                         05/25/09                   22,349,424.70
     05/25/09                         06/25/09                   21,431,048.19
     06/25/09                         07/25/09                   20,535,764.92
     07/25/09                         08/25/09                   19,663,248.62
     08/25/09                         09/25/09                   18,813,177.58
     09/25/09                         10/25/09                   17,985,234.57
     10/25/09                         11/25/09                   17,179,106.78
     11/25/09                         12/25/09                   16,394,485.79
     12/25/09                         01/25/10                   15,631,067.47
     01/25/10                         02/25/10                   14,888,551.94
     02/25/10                         03/25/10                   14,166,643.49
     03/25/10                         04/25/10                   13,465,050.57
     04/25/10                         05/25/10                   12,783,485.67
     05/25/10                         06/25/10                   12,121,665.32
     06/25/10                         07/25/10                   11,479,309.98
     07/25/10                         08/25/10                   10,856,144.04
     08/25/10                         09/25/10                   10,251,895.73
     09/25/10                         10/25/10                    9,666,297.08
     10/25/10                         11/25/10                    9,099,083.85
     11/25/10                         12/25/10                    8,549,995.51
     12/25/10                         01/25/11                    8,018,775.16
     01/25/11                         02/25/11                    7,505,169.48
     02/25/11                         03/25/11                    7,008,928.71
     03/25/11                         04/25/11                    6,529,806.57
     04/25/11                         05/25/11                    6,297,622.11
     05/25/11                         06/25/11                    6,081,301.47
     06/25/11                         07/25/11                    5,880,614.07
     07/25/11                         08/25/11                    5,695,332.66
     08/25/11                         09/25/11                    5,525,233.30
     09/25/11                         10/25/11                    5,370,095.25
     10/25/11                         11/25/11                    5,229,701.02
     11/25/11                         12/25/11                    5,103,836.25
     12/25/11                         01/25/12                    4,992,289.73
     01/25/12                         02/25/12                    4,894,853.28
     02/25/12                         03/25/12                    4,811,321.82
     03/25/12                         04/25/12                    4,741,493.22
     04/25/12                         05/25/12                    4,710,647.86
     05/25/12                         06/25/12                    4,679,802.50
     06/25/12                         07/25/12                    4,648,957.14
     07/25/12                         08/25/12                    4,618,111.78
     08/25/12                         09/25/12                    4,587,266.42
     09/25/12                         10/25/12                    4,556,421.06
     10/25/12                         11/25/12                    4,525,575.69
     11/25/12                         12/25/12                    4,494,730.33
     12/25/12                         01/25/13                    4,463,884.97
     01/25/13                         02/25/13                    4,433,039.61
     02/25/13                         03/25/13                    4,402,194.25
     03/25/13                         04/25/13                    4,371,348.89
     04/25/13                         05/25/13                    4,340,503.53
     05/25/13                         06/25/13                    4,309,658.17
     06/25/13                         07/25/13                    4,278,812.81
     07/25/13                         08/25/13                    4,247,967.45
     08/25/13                         09/25/13                    4,217,122.09
     09/25/13                         10/25/13                    4,186,276.73
     10/25/13                         11/25/13                    4,155,431.36
     11/25/13                         12/25/13                    4,124,586.00
     12/25/13                         01/25/14                    4,093,740.64
     01/25/14                         02/25/14                    4,062,895.28
     02/25/14                         03/25/14                    4,032,049.92
     03/25/14                         04/25/14                    4,001,204.56
     04/25/14                         05/25/14                    3,970,359.20
     05/25/14                         06/25/14                    3,939,513.84
     06/25/14                         07/25/14                    3,908,668.48
     07/25/14                         08/25/14                    3,877,823.12
     08/25/14                         09/25/14                    3,846,977.76
     09/25/14                         10/25/14                    3,816,132.40
     10/25/14                         11/25/14                    3,785,287.03
     11/25/14                         12/25/14                    3,754,441.67
     12/25/14                         01/25/15                    3,723,596.31
     01/25/15                         02/25/15                    3,692,750.95
     02/25/15                         03/25/15                    3,661,905.59
     03/25/15                         04/25/15                    3,631,060.23
     04/25/15                         05/25/15                    3,600,214.87
     05/25/15                         06/25/15                    3,569,369.51
     06/25/15                         07/25/15                    3,538,524.15
     07/25/15                         08/25/15                    3,507,678.79
     08/25/15                         09/25/15                    3,476,833.43
     09/25/15                         10/25/15                    3,445,988.07
     10/25/15                         11/25/15                    3,415,142.70
     11/25/15                         12/25/15                    3,384,297.34
     12/25/15                         01/25/16                    3,353,451.98
     01/25/16                         02/25/16                    3,322,606.62
     02/25/16                         03/25/16                    3,291,761.26
     03/25/16                         04/25/16                    3,260,915.90
     04/25/16                         05/25/16                    3,230,070.54
     05/25/16                         06/25/16                    3,199,225.18
     06/25/16                         07/25/16                    3,168,379.82
     07/25/16                         08/25/16                    3,137,534.46
     08/25/16                         09/25/16                    3,106,689.10
     09/25/16                         10/25/16                    3,075,843.74
     10/25/16                         11/25/16                    3,044,998.37
     11/25/16                         12/25/16                    3,014,153.01
     12/25/16                         01/25/17                    2,983,307.65
     01/25/17                         02/25/17                    2,952,462.29
     02/25/17                         03/25/17                    2,921,616.93
     03/25/17                         04/25/17                    2,890,771.57
     04/25/17                         05/25/17                    2,859,926.21
     05/25/17                         06/25/17                    2,829,080.85
     06/25/17                         07/25/17                    2,798,235.49
     07/25/17                         08/25/17                    2,767,390.13
     08/25/17                         09/25/17                    2,736,544.77
     09/25/17                         10/25/17                    2,705,699.41
     10/25/17                         11/25/17                    2,674,854.05
     11/25/17                         12/25/17                    2,644,008.68
     12/25/17                         01/25/18                    2,613,163.32
     01/25/18                         02/25/18                    2,582,317.96
     02/25/18                         03/25/18                    2,551,472.60
     03/25/18                         04/25/18                    2,520,627.24
     04/25/18                         05/25/18                    2,489,781.88
     05/25/18                         06/25/18                    2,458,936.52
     06/25/18                         07/25/18                    2,428,091.16
     07/25/18                         08/25/18                    2,397,245.80
     08/25/18                         09/25/18                    2,366,400.44
     09/25/18                         10/25/18                    2,335,555.08
     10/25/18                         11/25/18                    2,304,709.72
     11/25/18                         12/25/18                    2,273,864.35
     12/25/18                         01/25/19                    2,243,018.99
     01/25/19                         02/25/19                    2,212,173.63
     02/25/19                         03/25/19                    2,181,328.27
     03/25/19                         04/25/19                    2,150,482.91
     04/25/19                         05/25/19                    2,119,637.55
     05/25/19                         06/25/19                    2,088,792.19
     06/25/19                         07/25/19                    2,057,946.83
     07/25/19                         08/25/19                    2,027,101.47
     08/25/19                         09/25/19                    1,996,256.11
     09/25/19                         10/25/19                    1,965,410.75
     10/25/19                         11/25/19                    1,934,565.39
     11/25/19                         12/25/19                    1,903,720.02
     12/25/19                         01/25/20                    1,872,874.66
     01/25/20                         02/25/20                    1,819,487.98
     02/25/20                         03/25/20                    1,732,905.63
     03/25/20                         04/25/20                    1,647,152.10
     04/25/20                         05/25/20                    1,562,213.06
     05/25/20                         06/25/20                    1,478,074.36
     06/25/20                         07/25/20                    1,394,722.03
     07/25/20                         08/25/20                    1,312,142.30
     08/25/20                         09/25/20                    1,230,321.60
     09/25/20                         10/25/20                    1,149,246.51
     10/25/20                         11/25/20                    1,068,903.81
     11/25/20                         12/25/20                      989,280.45
     12/25/20                         01/25/21                      910,363.56
     01/25/21                         02/25/21                      831,528.55
     02/25/21                         03/25/21                      753,388.44
     03/25/21                         04/25/21                      675,930.63
     04/25/21                         05/25/21                      599,142.72
     05/25/21                         06/25/21                      523,012.43
     06/25/21                         07/25/21                      447,527.66
     07/25/21                         08/25/21                      372,676.49
     08/25/21                         09/25/21                      298,447.14
     09/25/21                         10/25/21                      224,828.00
     10/25/21                         11/25/21                      151,807.59
     11/25/21                         12/25/21                       79,374.60