Document:

MORTGAGE ASSET SECURITIZATION TRANSACTIONS, INC.

                                    Depositor

                         OPTION ONE MORTGAGE CORPORATION

                                 Master Servicer

                                       and

                WELLS FARGO BANK MINNESOTA, NATIONAL ASSOCIATION

                                     Trustee

                         POOLING AND SERVICING AGREEMENT
                          Dated as of February 1, 2003

                  MASTR Asset Backed Securities Trust 2003-OPT1
                       Mortgage Pass-Through Certificates

                                Series 2003-OPT1

<PAGE>

<TABLE>
<CAPTION>
                                                 TABLE OF CONTENTS

                                                     ARTICLE I

                                                    DEFINITIONS
<S>                                                                                                            <C>
SECTION 1.01.     Defined Terms.................................................................................-1-
SECTION 1.02.     Allocation of Certain Interest Shortfalls....................................................-47-

                                                    ARTICLE II

                                           CONVEYANCE OF MORTGAGE LOANS;
                                         ORIGINAL ISSUANCE OF CERTIFICATES
SECTION 2.01.     Conveyance of the Mortgage Loans.............................................................-49-
SECTION 2.02.     Acceptance of REMIC I by Trustee.............................................................-51-
SECTION 2.03.     Repurchase or Substitution of Mortgage Loans by the
                  Originator...................................................................................-52-
SECTION 2.04.     Reserved.....................................................................................-54-
SECTION 2.05.     Representations, Warranties and Covenants of the Master
                  Servicer.....................................................................................-54-
SECTION 2.06.     Issuance of the REMIC I Regular Interests and the Class R-I Interest.........................-57-
SECTION 2.07.     Conveyance of the REMIC I Regular Interests; Acceptance of REMIC
                  II by the Trustee............................................................................-57-
SECTION 2.08.     Conveyance of the REMIC II Regular Interests; Acceptance of REMIC
                  III by the Trustee...........................................................................-57-
SECTION 2.09.     Issuance of Class R Certificates.............................................................-58-

                                                    ARTICLE III

                                           ADMINISTRATION AND SERVICING
                                               OF THE MORTGAGE LOANS
SECTION 3.01.     Master Servicer to Act as Master Servicer....................................................-59-
SECTION 3.02.     Sub-Servicing Agreements Between Master Servicer and Sub-
                  Servicers....................................................................................-61-
SECTION 3.03.     Successor Sub-Servicers......................................................................-62-
SECTION 3.04.     Liability of the Master Servicer.............................................................-62-
SECTION 3.05.     No Contractual Relationship Between Sub-Servicers and the Trustee or
                  Certificateholders...........................................................................-63-
SECTION 3.06.     Assumption or Termination of Sub-Servicing Agreements by Trustee.............................-63-
SECTION 3.07.     Collection of Certain Mortgage Loan Payments.................................................-63-
SECTION 3.08.     Sub-Servicing Accounts.......................................................................-64-
SECTION 3.09.     Collection of Taxes, Assessments and Similar Items; Servicing
                  Accounts.....................................................................................-64-
SECTION 3.10.     Collection Account and Distribution Account..................................................-65-
SECTION 3.11.     Withdrawals from the Collection Account and Distribution Account.............................-67-
SECTION 3.12.     Investment of Funds in the Collection Account and the Distribution
                  Account......................................................................................-69-

                                                        -i-

<PAGE>

SECTION 3.13.     [Reserved]...................................................................................-70-
SECTION 3.14.     Maintenance of Hazard Insurance and Errors and Omissions and Fidelity
                  Coverage.....................................................................................-70-
SECTION 3.15.     Enforcement of Due-On-Sale Clauses; Assumption Agreements....................................-72-
SECTION 3.16.     Realization Upon Defaulted Mortgage Loans....................................................-73-
SECTION 3.17.     Trustee to Cooperate; Release of Mortgage Files..............................................-75-
SECTION 3.18.     Servicing Compensation.......................................................................-76-
SECTION 3.19.     Reports to the Trustee; Collection Account Statements........................................-76-
SECTION 3.20.     Statement as to Compliance...................................................................-77-
SECTION 3.21.     Independent Public Accountants' Servicing Report.............................................-77-
SECTION 3.22.     Access to Certain Documentation..............................................................-77-
SECTION 3.23.     Title, Management and Disposition of REO Property............................................-78-
SECTION 3.24.     Obligations of the Master Servicer in Respect of Prepayment Interest
                  Shortfalls...................................................................................-81-
SECTION 3.25.     Obligations of the Master Servicer in Respect of Mortgage Rates and
                  Monthly Payments.............................................................................-81-
SECTION 3.26.     Advance Facility.............................................................................-81-
SECTION 3.27.     Reserved.....................................................................................-82-
SECTION 3.28      Net WAC Rate Carryover Reserve Account.......................................................-82-
SECTION 3.29.     Excess Net WAC Rate Reserve Account..........................................................-84-

                                                    ARTICLE IV

                                          PAYMENTS TO CERTIFICATEHOLDERS
SECTION 4.01.     Distributions................................................................................-86-
SECTION 4.02.     Statements to Certificateholders.............................................................-95-
SECTION 4.03.     Remittance Reports; Advances.................................................................-97-
SECTION 4.04.     Allocation of Realized Losses................................................................-99-
SECTION 4.05.     Compliance with Withholding Requirements....................................................-101-

                                                     ARTICLE V

                                                 THE CERTIFICATES
SECTION 5.01.     The Certificate.............................................................................-105-
SECTION 5.02.     Registration of Transfer and Exchange of Certificates.......................................-106-
SECTION 5.03.     Mutilated, Destroyed, Lost or Stolen Certificates...........................................-111-
SECTION 5.04.     Persons Deemed Owners.......................................................................-111-
SECTION 5.05.     Certain Available Information...............................................................-111-

                                                    ARTICLE VI

                                       THE DEPOSITOR AND THE MASTER SERVICER
SECTION 6.01.     Liability of the Depositor and the Master Servicer..........................................-113-
SECTION 6.02.     Merger or Consolidation of the Depositor or the Master Servicer.............................-113-
SECTION 6.03.     Limitation on Liability of the Depositor, the Master Servicer and
                  Others......................................................................................-113-

                                                       -ii-

<PAGE>

SECTION 6.04.     Limitation on Resignation of the Master Servicer............................................-114-
SECTION 6.05.     Rights of the Depositor in Respect of the Master Servicer...................................-115-

                                                    ARTICLE VII

                                                      DEFAULT
SECTION 7.01.     Master Servicer Events of Default...........................................................-116-
SECTION 7.02.     Trustee to Act; Appointment of Successor....................................................-118-
SECTION 7.03.     Notification to Certificateholders..........................................................-119-
SECTION 7.04.     Waiver of Master Servicer Events of Default.................................................-119-

                                                   ARTICLE VIII

                                              CONCERNING THE TRUSTEE
SECTION 8.01.     Duties of Trustee...........................................................................-120-
SECTION 8.02.     Certain Matters Affecting the Trustee.......................................................-121-
SECTION 8.03.     Trustee not Liable for Certificates or Mortgage Loans.......................................-122-
SECTION 8.04.     Trustee May Own Certificates................................................................-122-
SECTION 8.05.     Trustee's Fees and Expenses.................................................................-122-
SECTION 8.06.     Eligibility Requirements for Trustee........................................................-123-
SECTION 8.07.     Resignation and Removal of the Trustee......................................................-123-
SECTION 8.08.     Successor Trustee...........................................................................-124-
SECTION 8.09.     Merger or Consolidation of Trustee..........................................................-124-
SECTION 8.10.     Appointment of Co-Trustee or Separate Trustee...............................................-125-
SECTION 8.11.     Appointment of Office or Agency.............................................................-126-
SECTION 8.12.     Representations and Warranties..............................................................-126-

                                                    ARTICLE IX

                                                    TERMINATION
SECTION 9.01.     Termination Upon Repurchase or Liquidation of All Mortgage
                  Loans.......................................................................................-128-
SECTION 9.02.     Additional Termination Requirements.........................................................-130-

                                                     ARTICLE X

                                                 REMIC PROVISIONS
SECTION 10.01.    REMIC Administration........................................................................-132-
SECTION 10.02.    Prohibited Transactions and Activities......................................................-134-
SECTION 10.03.    Master Servicer and Trustee Indemnification.................................................-135-

                                                    ARTICLE XI

                                             MISCELLANEOUS PROVISIONS
SECTION 11.01.             Amendment..........................................................................-136-
SECTION 11.02.             Recordation of Agreement; Counterparts.............................................-137-

                                                       -iii-

<PAGE>

SECTION 11.03.             Limitation on Rights of Certificateholders.........................................-137-
SECTION 11.04.             Governing Law......................................................................-138-
SECTION 11.05.             Notices............................................................................-138-
SECTION 11.06.             Severability of Provisions.........................................................-138-
SECTION 11.07.             Notice to Rating Agencies..........................................................-139-
SECTION 11.08.             Article and Section References.....................................................-140-
SECTION 11.09.             Grant of Security Interest.........................................................-140-
</TABLE>

                                                       -iv-

<PAGE>

<TABLE>
<CAPTION>
Exhibits
--------
<S>               <C>
Exhibit A-1       Form of Class A-1 Certificate
Exhibit A-2       Form of Class A-2 Certificate
Exhibit A-3       Form of Class M-1 Certificate
Exhibit A-4       Form of Class M-2 Certificate
Exhibit A-5       Form of Class M-3 Certificate
Exhibit A-6       Form of Class M-4 Certificate
Exhibit A-7       Form of Class MV-5 Certificate
Exhibit A-8       Form of Class MF-5 Certificate
Exhibit A-9       Form of Class CE Certificate
Exhibit A-10      Form of Class P Certificate
Exhibit A-11      Form of Class R Certificate
Exhibit B         [Reserved]
Exhibit C-1       Form of Trustee's Initial Certification
Exhibit C-2       Form of Trustee's Final Certification
Exhibit C-3       Form of Trustee's Receipt of Mortgage Notes
Exhibit D         Form of Mortgage Loan Purchase Agreement
Exhibit E         Request for Release
Exhibit F-1       Form of Transferor Representation Letter and Form of Transferee Representation
                  Letter in Connection with Transfer of the Class CE Certificates, Class P
                  Certificates or Residual Certificates Pursuant to Rule 144A Under the 1933 Act
Exhibit F-2       Form of Transfer Affidavit and Agreement and Form of Transferor Affidavit in
                  Connection with Transfer of Residual Certificates
Exhibit G         Form of Certification with respect to ERISA and the Code
Exhibit H         Form of Report Pursuant to Section 4.06
Exhibit I         Form of Lost Note Affidavit
Exhibit J-1       Form of Certification to Be Provided by the Master Servicer with Form 10-K
Exhibit J-2       Form of Certification to Be Provided by the Trustee with Form 10-K
Exhibit K         Loss Mitigation Procedures

Schedule 1        Mortgage Loan Schedule
Schedule 2        Prepayment Charge Schedule
Schedule 3        PMI Mortgage Loans
</TABLE>

                                       -v-

<PAGE>

                  This Pooling and Servicing Agreement, is dated and effective
as of February 1, 2003, among MORTGAGE ASSET SECURITIZATION TRANSACTIONS, INC.
as Depositor, OPTION ONE MORTGAGE CORPORATION as Master Servicer and WELLS FARGO
BANK MINNESOTA, NATIONAL ASSOCIATION as Trustee.

                             PRELIMINARY STATEMENT:

                  The Depositor intends to sell pass-through certificates to be
issued hereunder in multiple classes, which in the aggregate will evidence the
entire beneficial ownership interest in each REMIC (as defined herein) created
hereunder. The Trust Fund will consist of a segregated pool of assets comprised
of the Mortgage Loans and certain other related assets subject to this
Agreement.

                                     REMIC I
                                     -------

                  As provided herein, the Trustee will elect to treat the
segregated pool of assets consisting of the Mortgage Loans and certain other
related assets (other than the Master Servicer Prepayment Charge Payment Amount
and the Net WAC Rate Carryover Reserve Account) subject to this Agreement as a
REMIC for federal income tax purposes, and such segregated pool of assets will
be designated as "REMIC I." The Class R-I Interest will be the sole class of
"residual interests" in REMIC I for purposes of the REMIC Provisions (as defined
herein). The following table irrevocably sets forth the designation, the REMIC I
Remittance Rate, the initial Uncertificated Balance and, solely for purposes of
satisfying Treasury regulation section 1.860G-1(a)(4)(iii), the "latest possible
maturity date" for each of the REMIC I Regular Interests (as defined herein).
None of the REMIC I Regular Interests will be certificated.

                                      -vi-

<PAGE>

<TABLE>
<CAPTION>
                                      REMIC I                          Initial                    Latest Possible
       Designation                Remittance Rate               Uncertificated Balance            Maturity Date(1)
       -----------                ---------------               ----------------------            ----------------
<S>                               <C>                           <C>                               <C>
         I-LTAA                     Variable(2)                    $717,360,660.13                December 25, 2032
         I-LTA1                     Variable(2)                      $4,695,500.00                December 25, 2032
         I-LTA2                     Variable(2)                      $1,745,535.00                December 25, 2032
         I-LTM1                     Variable(2)                        $293,000.00                December 25, 2032
         I-LTM2                     Variable(2)                        $256,375.00                December 25, 2032
         I-LTM3                     Variable(2)                        $109,875.00                December 25, 2032
         I-LTM4                     Variable(2)                         $91,565.00                December 25, 2032
         I-LTMV5                    Variable(2)                         $23,250.00                December 25, 2032
         I-LTMF5                    Variable(2)                         $50,000.00                December 25, 2032
         I-LTZZ                     Variable(2)                      $7,374,913.47                December 25, 2032
          I-LTP                     Variable(2)                            $100.00                December 25, 2032
         I-1SUB                     Variable(2)                         $12,891.06                December 25, 2032
         I-1GRP                     Variable(2)                        $106,801.07                December 25, 2032
         I-2SUB                     Variable(2)                          $4,688.37                December 25, 2032
         I-2GRP                     Variable(2)                         $39,599.07                December 25, 2032
          I-XX                      Variable(2)                    $731,836,694.02                December 25, 2032
</TABLE>

________________
(1)      Solely for purposes of Section 1.860G-1(a)(4)(iii) of the Treasury
         regulations, the Distribution Date immediately following the maturity
         date for the Mortgage Loan with the latest maturity date has been
         designated as the "latest possible maturity date" for each REMIC I
         Regular Interest.
(2)      Calculated in accordance with the definition of "REMIC I Remittance
         Rate" herein.

                                      -vii-

<PAGE>

                                    REMIC II
                                    --------

                  As provided herein, the Trustee will elect to treat the
segregated pool of assets consisting of the REMIC I Regular Interests as a REMIC
for federal income tax purposes, and such segregated pool of assets will be
designated as "REMIC II." The Class R-II Interest will evidence the sole class
of "residual interests" in REMIC II for purposes of the REMIC Provisions under
federal income tax law. The following table irrevocably sets forth the
designation, the Pass-Through Rate, the initial aggregate Certificate Principal
Balance and, solely for purposes of satisfying Treasury regulation section
1.860G-1(a)(4)(iii), the "latest possible maturity date" for the indicated
Classes of Certificates.

<TABLE>
<CAPTION>
                                                                  Initial Aggregate
                                                                Certificate Principal            Latest Possible
         Designation                Pass-Through Rate                  Balance                  Maturity Date(1)
         -----------                -----------------                  -------                  ----------------
<S>                                 <C>                         <C>                             <C>
          Class A-1                    Variable(2)                $939,100,000.00               December 25, 2032
          Class A-2                    Variable(2)                $349,107,000.00               December 25, 2032
          Class M-1                    Variable(2)                 $58,600,000.00               December 25, 2032
          Class M-2                    Variable(2)                 $51,275,000.00               December 25, 2032
          Class M-3                    Variable(2)                 $21,975,000.00               December 25, 2032
          Class M-4                    Variable(2)                 $18,313,000.00               December 25, 2032
         Class MV-5                    Variable(2)                  $4,650,000.00               December 25, 2032
         Class MF-5                  6.00% per annum               $10,000,000.00               December 25, 2032
          Class CE                     Variable(2)                 $10,981,347.20(3)            December 25, 2032
           Class P                       N/A(5)                           $100.00               December 25, 2032
</TABLE>

_______________
(1)  Solely for purposes of Section 1.860G-1(a)(4)(iii) of the Treasury
     regulations, the Distribution Date immediately following the maturity date
     for the Mortgage Loans with the latest maturity date has been designated as
     the "latest possible maturity date" for each Class of Certificates.
(2)  Calculated in accordance with the definition of "Pass-Through Rate"
     herein.
(3)  The Class CE Certificates will accrue interest at their variable
     Pass-Through Rate on the Notional Amount of the Class CE Certificates
     outstanding from time to time which shall equal the Uncertificated Balance
     of the REMIC I Regular Interests. The Class CE Certificates will not accrue
     interest on their Certificate Principal Balance.
(5)  The Class P Certificates will not accrue interest.

                  As of the Cut-off Date, the Original Mortgage Loans had an
aggregate Principal Balance equal to $1,464,001,447.20.

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

                                     -viii-

<PAGE>

                                    ARTICLE I

                                   DEFINITIONS

                  SECTION 1.01.             Defined Terms.

                  Whenever used in this Agreement, including, without
limitation, in the Preliminary Statement hereto, the following words and
phrases, unless the context otherwise requires, shall have the meanings
specified in this Article. Unless otherwise specified, all calculations
described herein shall be made on the basis of a 360-day year consisting of
twelve 30-day months.

                  "Accepted Servicing Practices": The servicing standards set
forth in Section 3.01.

                  "Accrual Period": With respect to the Class A Certificates and
the Mezzanine Certificates (other than the Class MF-5 Certificates) and each
Distribution Date, the period commencing on the preceding Distribution Date (or
in the case of the first such Accrual Period, commencing on the Closing Date)
and ending on the day preceding the current Distribution Date. With respect to
the Class MF-5 Certificates, the Class CE Certificates and the REMIC I Regular
Interests and each Distribution Date, the calendar month prior to the month of
such Distribution Date.

                  "Adjustable-Rate Mortgage Loan": Each of the Mortgage Loans
identified in the Mortgage Loan Schedule as having a Mortgage Rate that is
subject to adjustment.

                  "Adjusted Net Maximum Mortgage Rate": With respect to any
Mortgage Loan (or the related REO Property), as of any date of determination, a
per annum rate of interest equal to the applicable Maximum Mortgage Rate for
such Mortgage Loan (or the Mortgage Rate in the case of any Fixed-Rate Mortgage
Loan) as of the first day of the month preceding the month in which the related
Distribution Date occurs minus the sum of (i) the Trustee Fee Rate, (ii) the
Servicing Fee Rate and (iii) the PMI Insurer Fee Rate, if applicable.

                  "Adjusted Net Mortgage Rate": With respect to any Mortgage
Loan (or the related REO Property), as of any date of determination, a per annum
rate of interest equal to the applicable Mortgage Rate for such Mortgage Loan as
of the first day of the month preceding the month in which the related
Distribution Date occurs minus the sum of (i) the Trustee Fee Rate, (ii) the
Servicing Fee Rate and (iii) the PMI Insurer Fee Rate, if applicable.

                  "Adjustment Date": With respect to each Adjustable-Rate
Mortgage Loan, the first day of the month in which the Mortgage Rate of such
Mortgage Loan changes pursuant to the related Mortgage Note. The first
Adjustment Date following the Cut-off Date as to each Adjustable-Rate Mortgage
Loan is set forth in the Mortgage Loan Schedule.

                  "Advance": As to any Mortgage Loan or REO Property, any
advance made by the Master Servicer in respect of any Distribution Date pursuant
to Section 4.03.

                  "Advancing Person": As defined in Section 3.29 hereof.

<PAGE>

                  "Affiliate": With respect to any specified Person, any other
Person controlling or controlled by or under common control with such specified
Person. For the purposes of this definition, "control" when used with respect to
any specified Person means the power to direct the management and policies of
such Person, directly or indirectly, whether through the ownership of voting
securities, by contract or otherwise, and the terms "controlling" and
"controlled" have meanings correlative to the foregoing.

                  "Aggregate Loss Severity Percentage": With respect to any
Distribution Date, the percentage equivalent of a fraction, the numerator of
which is the aggregate amount of Realized Losses incurred on any Mortgage Loans
from the Cut-off Date to the last day of the preceding calendar month and the
denominator of which is the aggregate principal balance of such Mortgage Loans
immediately prior to the liquidation of such Mortgage Loans.

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

                  "Allocated Realized Loss Amount": With respect to any
Distribution Date and any Class of Mezzanine Certificates, the sum of (i) any
Realized Losses allocated to such Class of Certificates on such Distribution
Date and (ii) the amount of any Allocated Realized Loss Amount for such Class of
Certificates remaining unpaid from the previous Distribution Date.

                  "Assignment": An assignment of Mortgage, notice of transfer or
equivalent instrument, in recordable form (excepting therefrom, if applicable,
the mortgage recordation information which has not been required pursuant to
Section 2.01 hereof or returned by the applicable recorder's office), which is
sufficient under the laws of the jurisdiction wherein the related Mortgaged
Property is located to reflect of record the sale of the Mortgage, which
assignment, notice of transfer or equivalent instrument may be in the form of
one or more blanket assignments covering Mortgages secured by Mortgaged
Properties located in the same county, if permitted by law.

                  "Available Funds": With respect to any Distribution Date, an
amount equal to the excess of (i) the sum of (a) the aggregate of the related
Monthly Payments received on the Mortgage Loans on or prior to the related
Determination Date, (b) Net Liquidation Proceeds, Insurance Proceeds, Principal
Prepayments, proceeds from repurchases of and substitutions for such Mortgage
Loans and other unscheduled recoveries of principal and interest in respect of
the Mortgage Loans received during the related Prepayment Period, (c) the
aggregate of any amounts received in respect of a related REO Property withdrawn
from any REO Account and deposited in the Collection Account for such
Distribution Date, (d) the aggregate of any amounts deposited in the Collection
Account by the Master Servicer in respect of related Prepayment Interest
Shortfalls for such Distribution Date, (e) the aggregate of any Advances made by
the Master Servicer for such Distribution Date in respect of the Mortgage Loans
and (f) the aggregate of any related advances made by the Trustee in respect of
the Mortgage Loans for such Distribution Date pursuant to Section 7.02 over (ii)
the sum of (a) amounts reimbursable or payable to the Master Servicer pursuant
to Section 3.11(a), (b) Extraordinary Trust Fund Expenses reimbursable to the
Trustee pursuant to Section 3.11(b), (c) amounts deposited in the Collection
Account or the Distribution Account pursuant to clauses (a) through (g) above,
as the case may be, in error, (d) the amount of any Prepayment Charges collected
by the Master Servicer in connection with the full or partial

                                       -2-

<PAGE>

prepayment of any of the Mortgage Loans and any Master Servicer Prepayment
Charge Payment Amount, (e) the Trustee Fee and any indemnification amounts owed
to the Trustee payable from the Distribution Account pursuant to Section 8.05
and (f) the PMI Insurer Fee payable from the Distribution Account.

                  "Balloon Mortgage Loan": A Mortgage Loan that provides for the
payment of the unamortized principal balance of such Mortgage Loan in a single
payment at the maturity of such Mortgage Loan that is substantially greater than
the preceding monthly payment.

                  "Balloon Payment": A payment of the unamortized principal
balance of a Mortgage Loan in a single payment at the maturity of such Mortgage
Loan that is substantially greater than the preceding Monthly Payment.

                  "Bankruptcy Code": The Bankruptcy Reform Act of 1978 (Title 11
of the United States Code), as amended.

                  "Book-Entry Certificate": The Class A Certificates and the
Mezzanine Certificates for so long as the Certificates of such Class shall be
registered in the name of the Depository or its nominee.

                  "Book-Entry Custodian": The custodian appointed pursuant to
Section 5.01.

                  "Business Day": Any day other than a Saturday, a Sunday or a
day on which banking or savings and loan institutions in the State of
California, the State of New York, the Commonwealth of Pennsylvania, or in the
cities in which the Corporate Trust Office of the Trustee is located, are
authorized or obligated by law or executive order to be closed.

                  "Cap Contract": The Cap Contract between the Trustee on behalf
of the Trust Fund and the counterparty thereunder, for the benefit of the
Holders of the Class A-2 Certificates and the Mezzanine Certificates (other than
the Class MF-5 Certificates).

                  "Certificate": Any one of the Mortgage Pass-Through
Certificates, Series 2003-OPT1, Class A-1, Class A-2, Class M-1, Class M-2,
Class M-3, Class M-4, Class MV-5, Class MF-5, Class CE, Class P or Class R,
issued under this Agreement.

                  "Certificate Factor": With respect to any Class of Regular
Certificates as of any Distribution Date, a fraction, expressed as a decimal
carried to six places, the numerator of which is the aggregate Certificate
Principal Balance (or the Notional Amount, in the case of the Class CE
Certificates) of such Class of Certificates on such Distribution Date (after
giving effect to any distributions of principal and allocations of Realized
Losses in reduction of the Certificate Principal Balance (or the Notional
Amount, in the case of the Class CE Certificates) of such Class of Certificates
to be made on such Distribution Date), and the denominator of which is the
initial aggregate Certificate Principal Balance (or the Notional Amount, in the
case of the Class CE Certificates) of such Class of Certificates as of the
Closing Date.

                  "Certificate Margin": With respect to the Class A-1
Certificates and REMIC I Regular

                                       -3-

<PAGE>

Interest I-LTA1, 1.000% in the case of each Distribution Date through and
including the Distribution Date on which the aggregate Principal Balance of the
Mortgage Loans (and properties acquired in respect thereof) remaining in the
Trust Fund is reduced to less than 10% of the aggregate Cut-off Date Principal
Balance of the Mortgage Loans and 1.500% in the case of each Distribution Date
thereafter.

                  With respect to the Class A-2 Certificates and REMIC I Regular
Interest I-LTA2, 0.420% in the case of each Distribution Date through and
including the Distribution Date on which the aggregate Principal Balance of the
Mortgage Loans (and properties acquired in respect thereof) remaining in the
Trust Fund is reduced to less than 10% of the aggregate Cut-off Date Principal
Balance of the Mortgage Loans and 0.840% in the case of each Distribution Date
thereafter.

                  With respect to the Class M-1 Certificates and REMIC I Regular
Interest I-LTM1, 0.850% in the case of each Distribution Date through and
including the Distribution Date on which the aggregate Principal Balance of the
Mortgage Loans (and properties acquired in respect thereof) remaining in the
Trust Fund is reduced to less than 10% of the aggregate Cut-off Date Principal
Balance of the Mortgage Loans and 1.275% in the case of each Distribution Date
thereafter.

                  With respect to the Class M-2 Certificates and REMIC I Regular
Interest I-LTM2, 1.850% in the case of each Distribution Date through and
including the Distribution Date on which the aggregate Principal Balance of the
Mortgage Loans (and properties acquired in respect thereof) remaining in the
Trust Fund is reduced to less than 10% of the aggregate Cut-off Date Principal
Balance of the Mortgage Loans and 2.775% in the case of each Distribution Date
thereafter.

                  With respect to the Class M-3 Certificates and REMIC I Regular
Interest I-LTM3, 2.750% in the case of each Distribution Date through and
including the Distribution Date on which the aggregate Principal Balance of the
Mortgage Loans (and properties acquired in respect thereof) remaining in the
Trust Fund is reduced to less than 10% of the aggregate Cut-off Date Principal
Balance of the Mortgage Loans and 4.125% in the case of each Distribution Date
thereafter.

                  With respect to the Class M-4 Certificates and REMIC I Regular
Interest I-LTM4, 3.900% in the case of each Distribution Date through and
including the Distribution Date on which the aggregate Principal Balance of the
Mortgage Loans (and properties acquired in respect thereof) remaining in the
Trust Fund is reduced to less than 10% of the aggregate Cut-off Date Principal
Balance of the Mortgage Loans and 5.850% in the case of each Distribution Date
thereafter.

                  With respect to the Class MV-5 Certificates and REMIC I
Regular Interest I-LTMV5, 3.500% in the case of each Distribution Date through
and including the Distribution Date on which the aggregate Principal Balance of
the Mortgage Loans (and properties acquired in respect thereof) remaining in the
Trust Fund is reduced to less than 10% of the aggregate Cut-off Date Principal
Balance of the Mortgage Loans and 5.250% in the case of each Distribution Date
thereafter.

                  "Certificateholder" or "Holder": The Person in whose name a
Certificate is registered in the Certificate Register, except that a
Disqualified Organization or a Non-United States Person shall not be a Holder of
a Residual Certificate for any purposes hereof and, solely for the purposes of
giving any consent pursuant to this Agreement, any Certificate registered in the
name of the

                                       -4-

<PAGE>

Depositor or the Master Servicer or any Affiliate thereof shall be deemed not to
be outstanding and the Voting Rights to which it is entitled shall not be taken
into account in determining whether the requisite percentage of Voting Rights
necessary to effect any such consent has been obtained, except as otherwise
provided in Section 11.01. The Trustee and the NIMS Insurer may conclusively
rely upon a certificate of the Depositor or the Master Servicer in determining
whether a Certificate is held by an Affiliate thereof. All references herein to
"Holders" or "Certificateholders" shall reflect the rights of Certificate Owners
as they may indirectly exercise such rights through the Depository and
participating members thereof, except as otherwise specified herein; provided,
however, that the Trustee and the NIMS Insurer shall be required to recognize as
a "Holder" or "Certificateholder" only the Person in whose name a Certificate is
registered in the Certificate Register.

                  "Certificate Owner": With respect to a Book-Entry Certificate,
the Person who is the beneficial owner of such Certificate as reflected on the
books of the Depository or on the books of a Depository Participant or on the
books of an indirect participating brokerage firm for which a Depository
Participant acts as agent.

                  "Certificate Principal Balance": With respect to each Class A
Certificate, Mezzanine Certificate or Class P Certificate as of any date of
determination, the Certificate Principal Balance of such Certificate on the
Distribution Date immediately prior to such date of determination, minus all
distributions allocable to principal made thereon and Realized Losses allocated
thereto on such immediately prior Distribution Date (or, in the case of any date
of determination up to and including the first Distribution Date, the initial
Certificate Principal Balance of such Certificate, as stated on the face
thereof). With respect to each Class CE Certificate as of any date of
determination, an amount equal to the Percentage Interest evidenced by such
Certificate times the excess, if any, of (A) the then aggregate Uncertificated
Balances of the REMIC I Regular Interests over (B) the then aggregate
Certificate Principal Balances of the Class A Certificates, the Mezzanine
Certificates and the Class P Certificates then outstanding.

                  "Certificate Register": The register maintained pursuant to
Section 5.02.

                  "Class": Collectively, all of the Certificates bearing the
same class designation.

                  "Class A Certificates": Any Class A-1 Certificate or Class A-2
Certificate.

                  "Class A Principal Distribution Amount": With respect to any
Distribution Date, the sum of (i) the Class A-1 Principal Distribution Amount
and (ii) the Class A-2 Principal Distribution Amount.

                  "Class A-1 Certificate": Any one of the Class A-1 Certificates
executed, authenticated and delivered by the Trustee, substantially in the form
annexed hereto as Exhibit A-1 and evidencing a Regular Interest in REMIC II for
purposes of the REMIC Provisions.

                  "Class A-1 Principal Distribution Amount": The excess of (x)
the Certificate Principal Balance of the Class A-1 Certificates immediately
prior to such Distribution Date over (y) the lesser of (A) the product of (i)
76.00% and (ii) the aggregate Stated Principal Balance of the Group I Mortgage
Loans as of the last day of the related Due Period (after giving effect to
scheduled

                                       -5-

<PAGE>

payments of principal due during the related Due Period, to the extent received
or advanced, and unscheduled collections of principal received during the
related Prepayment Period) and (B) the aggregate Stated Principal Balance of the
Group I Mortgage Loans as of the last day of the related Due Period (after
giving effect to scheduled payments of principal due during the related Due
Period, to the extent received or advanced, and unscheduled collections of
principal received during the related Prepayment Period) minus $5,340,054.

                  "Class A-2 Certificate": Any one of the Class A-2 Certificates
executed, authenticated and delivered by the Trustee, substantially in the form
annexed hereto as Exhibit A-2 and evidencing a Regular Interest in REMIC II for
purposes of the REMIC Provisions.

                  "Class A-2 Principal Distribution Amount": The excess of (x)
the Certificate Principal Balance of the Class A-2 Certificates immediately
prior to such Distribution Date over (y) the lesser of (A) the product of (i)
76.00% and (ii) the aggregate Stated Principal Balance of the Group II Mortgage
Loans as of the last day of the related Due Period (after giving effect to
scheduled payments of principal due during the related Due Period, to the extent
received or advanced, and unscheduled collections of principal received during
the related Prepayment Period) and (B) the aggregate Stated Principal Balance of
the Group II Mortgage Loans as of the last day of the related Due Period (after
giving effect to scheduled payments of principal due during the related Due
Period, to the extent received or advanced, and unscheduled collections of
principal received during the related Prepayment Period) minus $1,979,954.

                  "Class CE Certificate": Any one of the Class CE Certificates
executed, authenticated and delivered by the Trustee, substantially in the form
annexed hereto as Exhibit A-9 and evidencing a Regular Interest in REMIC II for
purposes of the REMIC Provisions.

                  "Class M-1 Certificate": Any one of the Class M-1 Certificates
executed, authenticated and delivered by the Trustee, substantially in the form
annexed hereto as Exhibit A-3 and evidencing a Regular Interest in REMIC II for
purposes of the REMIC Provisions.

                  "Class M-1 Principal Distribution Amount": The excess of (x)
the sum of (i) the Certificate Principal Balance of the Class A Certificates
(after taking into account the distribution of the Class A Principal
Distribution Amount on such Distribution Date) and (ii) the Certificate
Principal Balance of the Class M-1 Certificates immediately prior to such
Distribution Date over (y) the lesser of (A) the product of (i) 84.00% and (ii)
the aggregate Stated Principal Balance of the Mortgage Loans as of the last day
of the related Due Period (after giving effect to scheduled payments of
principal due during the related Due Period, to the extent received or advanced,
and unscheduled collections of principal received during the related Prepayment
Period) and (B) the aggregate Stated Principal Balance of the Mortgage Loans as
of the last day of the related Due Period (after giving effect to scheduled
payments of principal due during the related Due Period, to the extent received
or advanced, and unscheduled collections of principal received during the
related Prepayment Period) minus $7,320,007.

                  "Class M-2 Certificate": Any one of the Class M-2 Certificates
executed, authenticated and delivered by the Trustee, substantially in the form
annexed hereto as Exhibit A-4 and evidencing a Regular Interest in REMIC II for
purposes of the REMIC Provisions.

                                       -6-

<PAGE>

                  "Class M-2 Principal Distribution Amount": The excess of (x)
the sum of (i) the Certificate Principal Balance of the Class A Certificates
(after taking into account the distribution of the Class A Principal
Distribution Amount on such Distribution Date), (ii) the Certificate Principal
Balance of the Class M-1 Certificates (after taking into account the
distribution of the Class M-1 Principal Distribution Amount on such Distribution
Date) and (iii) the Certificate Principal Balance of the Class M-2 Certificates
immediately prior to such Distribution Date over (y) the lesser of (A) the
product of (i) 91.00% and (ii) the aggregate Stated Principal Balance of the
Mortgage Loans as of the last day of the related Due Period (after giving effect
to scheduled payments of principal due during the related Due Period, to the
extent received or advanced, and unscheduled collections of principal received
during the related Prepayment Period) and (B) the aggregate Stated Principal
Balance of the Mortgage Loans as of the last day of the related Due Period
(after giving effect to scheduled payments of principal due during the related
Due Period, to the extent received or advanced, and unscheduled collections of
principal received during the related Prepayment Period) minus $7,320,007.

                  "Class M-3 Certificate": Any one of the Class M-3 Certificates
executed, authenticated and delivered by the Trustee, substantially in the form
annexed hereto as Exhibit A-5 and evidencing a Regular Interest in REMIC II for
purposes of the REMIC Provisions.

                  "Class M-3 Principal Distribution Amount": With respect to any
Distribution Date, the excess of (x) the sum of (i) the Certificate Principal
Balance of the Class A Certificates (after taking into account the distribution
of the Class A Principal Distribution Amount on such Distribution Date), (ii)
the Certificate Principal Balance of the Class M-1 Certificates (after taking
into account the distribution of the Class M-1 Principal Distribution Amount on
such Distribution Date), (iii) the Certificate Principal Balance of the Class
M-2 Certificates (after taking into account the distribution of the Class M-2
Principal Distribution Amount on such Distribution Date) and (iv) the
Certificate Principal Balance of the Class M-3 Certificates immediately prior to
such Distribution Date over (y) the lesser of (A) the product of (i) 94.00% and
(ii) the aggregate Stated Principal Balance of the Mortgage Loans as of the last
day of the related Due Period (after giving effect to scheduled payments of
principal due during the related Due Period, to the extent received or advanced,
and unscheduled collections of principal received during the related Prepayment
Period) and (B) the aggregate Stated Principal Balance of the Mortgage Loans as
of the last day of the related Due Period (after giving effect to scheduled
payments of principal due during the related Due Period, to the extent received
or advanced, and unscheduled collections of principal received during the
related Prepayment Period) minus $7,320,007.

                  "Class M-4 Certificate": Any one of the Class M-4 Certificates
executed, authenticated and delivered by the Trustee, substantially in the form
annexed hereto as Exhibit A-6 and evidencing a Regular Interest in REMIC II for
purposes of the REMIC Provisions.

                  "Class M-4 Principal Distribution Amount": With respect to any
Distribution Date, the excess of (x) the sum of (i) the Certificate Principal
Balance of the Class A Certificates (after taking into account the distribution
of the Class A Principal Distribution Amount on such Distribution Date), (ii)
the Certificate Principal Balance of the Class M-1 Certificates (after taking
into account the distribution of the Class M-1 Principal Distribution Amount on
such Distribution

                                       -7-

<PAGE>

Date), (iii) the Certificate Principal Balance of the Class M-2 Certificates
(after taking into account the distribution of the Class M-2 Principal
Distribution Amount on such Distribution Date), (iv) the Certificate Principal
Balance of the Class M-3 Certificates (after taking into account the
distribution of the Class M-2 Principal Distribution Amount on such Distribution
Date) and (v) the Certificate Principal Balance of the Class M-4 Certificates
immediately prior to such Distribution Date over (y) the lesser of (A) the
product of (i) 96.50% and (ii) the aggregate Stated Principal Balance of the
Mortgage Loans as of the last day of the related Due Period (after giving effect
to scheduled payments of principal due during the related Due Period, to the
extent received or advanced, and unscheduled collections of principal received
during the related Prepayment Period) and (B) the aggregate Stated Principal
Balance of the Mortgage Loans as of the last day of the related Due Period
(after giving effect to scheduled payments of principal due during the related
Due Period, to the extent received or advanced, and unscheduled collections of
principal received during the related Prepayment Period) minus $7,320,007.

                  "Class M-5 Principal Distribution Amount": With respect to any
Distribution Date, the excess of (x) the sum of (i) the Certificate Principal
Balance of the Class A Certificates (after taking into account the distribution
of the Class A Principal Distribution Amount on such Distribution Date), (ii)
the Certificate Principal Balance of the Class M-1 Certificates (after taking
into account the distribution of the Class M-1 Principal Distribution Amount on
such Distribution Date), (iii) the Certificate Principal Balance of the Class
M-2 Certificates (after taking into account the distribution of the Class M-2
Principal Distribution Amount on such Distribution Date), (iv) the Certificate
Principal Balance of the Class M-3 Certificates (after taking into account the
distribution of the Class M-3 Principal Distribution Amount on such Distribution
Date), (v) the Certificate Principal Balance of the Class M-4 Certificates
(after taking into account the distribution of the Class M-4 Principal
Distribution Amount on such Distribution Date) and (vi) the aggregate
Certificate Principal Balance of the Class MV-5 Certificates and the Class MF-5
Certificates immediately prior to such Distribution Date over (y) the lesser of
(A) the product of (i) 98.50% and (ii) the aggregate Stated Principal Balance of
the Mortgage Loans as of the last day of the related Due Period (after giving
effect to scheduled payments of principal due during the related Due Period, to
the extent received or advanced, and unscheduled collections of principal
received during the related Prepayment Period) and (B) the aggregate Stated
Principal Balance of the Mortgage Loans as of the last day of the related Due
Period (after giving effect to scheduled payments of principal due during the
related Due Period, to the extent received or advanced, and unscheduled
collections of principal received during the related Prepayment Period) minus
$7,320,007.

                  "Class MF-5 Certificate": Any one of the Class MF-5
Certificates executed, authenticated and delivered by the Trustee, substantially
in the form annexed hereto as Exhibit A-8 and evidencing a Regular Interest in
REMIC II for purposes of the REMIC Provisions.

                  "Class MV-5 Certificate": Any one of the Class MV-5
Certificates executed, authenticated and delivered by the Trustee, substantially
in the form annexed hereto as Exhibit A-7 and evidencing a Regular Interest in
REMIC II for purposes of the REMIC Provisions.

                  "Class P Certificate": Any one of the Class P Certificates
executed, authenticated and delivered by the Trustee, substantially in the form
annexed hereto as Exhibit A-10 and evidencing a Regular Interest in REMIC II for
purposes of the REMIC Provisions.

                                       -8-

<PAGE>

                  "Class R Certificate": Any one of the Class R Certificates
executed, authenticated and delivered by the Trustee, substantially in the form
annexed hereto as Exhibit A-12 and evidencing the ownership of the Class R-I
Interest and the Class R-II Interest.

                  "Class R-I Interest": The uncertificated Residual Interest in
REMIC I.

                  "Class R-II Interest": The uncertificated Residual Interest in
REMIC II.

                  "Closing Date": February 27, 2003.

                  "Code": The Internal Revenue Code of 1986.

                  "Collection Account": The account or accounts created and
maintained, or caused to be created and maintained, by the Master Servicer
pursuant to Section 3.10(a), which shall be entitled "Option One Mortgage
Corporation, as Master Servicer for Wells Fargo Bank Minnesota, National
Association, as Trustee, in trust for the registered holders of MASTR Asset
Backed Securities Trust 2003-OPT1, Mortgage Pass-Through Certificates." The
Collection Account must be an Eligible Account.

                  "Commission":  The Securities and Exchange Commission.

                  "Compensating Interest":  As defined in Section 3.24 hereof.

                  "Corporate Trust Office": The principal corporate trust office
of the Trustee at which at any particular time its corporate trust business in
connection with this Agreement shall be administered, which office, at the date
of the execution of this instrument is located (i) for Certificate transfer
purposes, at Sixth and Marquette, Minneapolis, Minnesota 55479-0113, Attention:
MASTR Series 2003-OPT1 and (ii) for all other purposes, at 9062 Old Annapolis
Road, Columbia, Maryland 21045, Attention: MASTR Series 2003-OPT1, or at such
other address as the Trustee may designate from time to time by notice to the
Certificateholders, the Depositor and the Master Servicer.

                  "Corresponding Certificate": With respect to (i) REMIC I
Regular Interest I-LTA1, (ii) REMIC I Regular Interest I-LTA2, (iii) REMIC I
Regular Interest I-LTM1, (iv) REMIC I Regular Interest I-LTM2, (v) REMIC I
Regular Interest I-LTM3, (vi) REMIC I Regular Interest I-LTM4, (vii) REMIC I
Regular Interest I-LTMV5, (viii) REMIC I Regular Interest I-LTMF5 and (ix) REMIC
I Regular Interest I-LTP, (i) the Class A-1 Certificates, (ii) the Class A-2
Certificates, (iii) the Class M-1 Certificates, (iv) the Class M-2 Certificates,
(v) the Class M-3 Certificates, (vi) the Class M-4 Certificates, (vii) the Class
MV-5 Certificates, (viii) the Class MF-5 Certificates and (ix) the Class P
Certificates, respectively.

                  "Credit Enhancement Percentage": For any Distribution Date,
the percentage equivalent of a fraction, the numerator of which is the sum of
the aggregate Certificate Principal Balances of the Mezzanine Certificates and
the Class CE Certificates, and the denominator of which is the aggregate Stated
Principal Balance of the Mortgage Loans, calculated prior to taking into account
distributions of principal on the Mortgage Loans and distribution of the Group I
Principal

                                       -9-

<PAGE>

Distribution Amount and the Group II Principal Distribution Amount to the
Certificates then entitled to distributions of principal on such Distribution
Date.

                  "Cumulative Loss Percentage": With respect to any Distribution
Date, the percentage equivalent of a fraction, the numerator of which is the
aggregate amount of Realized Losses incurred from the Cut-off Date to the last
day of the preceding calendar month and the denominator of which is the sum of
the aggregate Stated Principal Balance of the Mortgage Loans as of the Cut-off
Date.

                  "Cut-off Date": With respect to each Original Mortgage Loan,
February 1, 2003. With respect to all Qualified Substitute Mortgage Loans, their
respective dates of substitution. References herein to the "Cut-off Date," when
used with respect to more than one Mortgage Loan, shall be to the respective
Cut-off Dates for such Mortgage Loans.

                  "Cut-off Date Principal Balance": With respect to any Mortgage
Loan, the unpaid principal balance thereof as of the Cut-off Date of such
Mortgage Loan (or as of the applicable date of substitution with respect to a
Qualified Substitute Mortgage Loan), after giving effect to scheduled payments
due on or before the Cut-off Date, whether or not received.

                  "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 resulting from a Deficient Valuation.

                  "Deficient Valuation": With respect to any Mortgage Loan, a
valuation of the related Mortgaged Property by a court of competent jurisdiction
in an amount less than the then outstanding principal balance of the Mortgage
Loan, which valuation results from a proceeding initiated under the Bankruptcy
Code.

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

                  "Deleted Mortgage Loan": A Mortgage Loan replaced or to be
replaced by a Qualified Substitute Mortgage Loan.

                   "Delinquency Master Servicer Termination Trigger": A
Delinquency Master Servicer Termination Trigger will have occurred with respect
to the Certificates on a Distribution Date if the Three Month Rolling
Delinquency Percentage for the Mortgage Loans exceeds 18.00%.

                  "Delinquency Percentage": As of the last day of the related
Due Period, the percentage equivalent of a fraction, the numerator of which is
the aggregate Stated Principal Balance of all Mortgage Loans that, as of the
last day of the previous calendar month, are 60 or more days delinquent, are in
foreclosure, have been converted to REO Properties or have been discharged by
reason of bankruptcy, and the denominator of which is the aggregate Stated
Principal Balance of the Mortgage Loans and REO Properties as of the last day of
the previous calendar month.

                  "Depositor": Mortgage Asset Securitization Transactions, Inc.,
a Delaware corporation, or its successor in interest.

                                      -10-

<PAGE>

                  "Depository": The Depository Trust Company, or any successor
Depository hereafter named. The nominee of the initial Depository, for purposes
of registering those Certificates that are to be Book-Entry Certificates, is
CEDE & Co. The Depository shall at all times be a "clearing corporation" as
defined in Section 8-102(3) of the Uniform Commercial Code of the State of New
York and a "clearing agency" registered pursuant to the provisions of Section
17A of the Securities Exchange Act of 1934, as amended.

                  "Depository Participant": A broker, dealer, bank or other
financial institution or other Person for whom from time to time a Depository
effects book-entry transfers and pledges of securities deposited with the
Depository.

                  "Determination Date": With respect to any Distribution Date,
the 15th day of the calendar month in which such Distribution Date occurs or, if
such 15th day is not a Business Day, the Business Day immediately preceding such
15th day.

                  "Directly Operate": With respect to any REO Property, the
furnishing or rendering of services to the tenants thereof, the management or
operation of such REO Property, the holding of such REO Property primarily for
sale to customers, the performance of any construction work thereon or any use
of such REO Property in a trade or business conducted by REMIC I other than
through an Independent Contractor; provided, however, that the Trustee (or the
Master Servicer on behalf of the Trustee) shall not be considered to Directly
Operate an REO Property solely because the Trustee (or the Master Servicer on
behalf of the Trustee) establishes rental terms, chooses tenants, enters into or
renews leases, deals with taxes and insurance, or makes decisions as to repairs
or capital expenditures with respect to such REO Property.

                  "Disqualified Organization": Any of the following: (i) the
United States, any State or political subdivision thereof, any possession of the
United States, or any agency or instrumentality of any of the foregoing (other
than an instrumentality which is a corporation if all of its activities are
subject to tax and, except for Freddie Mac, a majority of its board of directors
is not selected by such governmental unit), (ii) any foreign government, any
international organization, or any agency or instrumentality of any of the
foregoing, (iii) any organization (other than certain farmers'cooperatives
described in Section 521 of the Code) which is exempt from the tax imposed by
Chapter 1 of the Code (including the tax imposed by Section 511 of the Code on
unrelated business taxable income), (iv) rural electric and telephone
cooperatives described in Section 1381(a)(2)(C) of the Code, (v) an "electing
large partnership" and (vi) any other Person so designated by the Trustee based
upon an Opinion of Counsel that the holding of an Ownership Interest in a
Residual Certificate by such Person may cause any of REMIC I or REMIC II or any
Person having an Ownership Interest in any Class of Certificates (other than
such Person) to incur a liability for any federal tax imposed under the Code
that would not otherwise be imposed but for the Transfer of an Ownership
Interest in a Residual Certificate to such Person. The terms "United States,"
"State" and "international organization" shall have the meanings set forth in
Section 7701 of the Code or successor provisions.

                  "Distribution Account": The trust account or accounts created
and maintained by the Trustee pursuant to Section 3.10(b), which shall be
entitled "Wells Fargo Bank Minnesota, National Association, as Trustee, in trust
for the registered holders of MASTR Asset Backed Securities Trust

                                      -11-

<PAGE>

2003-OPT1, Mortgage Pass-Through Certificates." The Distribution Account must be
an Eligible Account.

                  "Distribution Date": The 25th day of any month, or if such
25th day is not a Business Day, the Business Day immediately following such 25th
day, commencing in March 2003.

                  "Due Date": With respect to each Distribution Date, the first
day of the calendar month in which such Distribution Date occurs, which is
generally the day of the month on which the Monthly Payment is due on a Mortgage
Loan, exclusive of any days of grace.

                  "Due Period": With respect to any Distribution Date, the
period commencing on the second day of the month immediately preceding the month
in which such Distribution Date occurs and ending on the related Due Date.

                  "Eligible Account": Any of (i) an account or accounts
maintained with a federal or state chartered depository institution or trust
company the short-term unsecured debt obligations of which (or, in the case of a
depository institution or trust company that is the principal subsidiary of a
holding company, the short-term unsecured debt obligations of such holding
company) are rated P-1 by Moody's, F-1 by Fitch or A-1+ by S&P (or comparable
ratings if Moody's, Fitch and S&P are not the Rating Agencies) at the time any
amounts are held on deposit therein, (ii) an account or accounts the deposits in
which are fully insured by the FDIC (to the limits established by such
corporation), the uninsured deposits in which account are otherwise secured such
that, as evidenced by an Opinion of Counsel delivered to the NIMS Insurer, the
Trustee and to each Rating Agency, the Certificateholders will have a claim with
respect to the funds in such account or a perfected first priority security
interest against such collateral (which shall be limited to Permitted
Investments) securing such funds that is superior to claims of any other
depositors or creditors of the depository institution with which such account is
maintained, (iii) a trust account or accounts maintained with the trust
department of a federal or state chartered depository institution, national
banking association or trust company acting in its fiduciary capacity or (iv) an
account otherwise acceptable to the NIMS Insurer and to each Rating Agency
without reduction or withdrawal of their then current ratings of the
Certificates as evidenced by a letter from each Rating Agency to the Trustee and
the NIMS Insurer. Eligible Accounts may bear interest.

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

                  "Escrow Payments": The amounts constituting ground rents,
taxes, assessments, water rates, fire and hazard insurance premiums and other
payments required to be escrowed by the Mortgagor with the mortgagee pursuant to
any Mortgage Loan.

                  "Estate in Real Property": A fee simple estate in a parcel of
land.

                  "Excess Overcollateralized Amount": With respect to the Class
A Certificates and the Mezzanine Certificates and any Distribution Date, the
excess, if any, of (i) the Overcollateralized Amount for such Distribution Date,
assuming that 100% of the Principal Remittance Amount is applied as a principal
payment on such Distribution Date over (ii) the Overcollateralization Target
Amount for such Distribution Date.

                                      -12-

<PAGE>

                  "Extra Principal Distribution Amount": With respect to any
Distribution Date, the lesser of (x) the Monthly Interest Distributable Amount
payable on the Class CE Certificates on such Distribution Date as reduced by
Realized Losses allocated thereto with respect to such Distribution Date
pursuant to Section 4.04 and (y) the Overcollateralization Deficiency Amount for
such Distribution Date.

                  "Extraordinary Trust Fund Expense": Any amounts reimbursable
to the Trustee, or any director, officer, employee or agent of the Trustee from
the Trust Fund pursuant to Section 8.05 or Section 10.01(c) and any amounts
payable from the Distribution Account in respect of taxes pursuant to Section
10.01(g)(iii).

                  "Fannie Mae": Fannie Mae, formally known as the Federal
National Mortgage Association, or any successor thereto.

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

                  "Final Recovery Determination": With respect to any defaulted
Mortgage Loan or any REO Property (other than a Mortgage Loan or REO Property
purchased by the Originator, the Seller, the Depositor or the Master Servicer
pursuant to or as contemplated by Section 2.03, Section 3.16(c) or Section
9.01), a determination made by the Master Servicer that all Insurance Proceeds,
Liquidation Proceeds and other payments or recoveries which the Master Servicer,
in its reasonable good faith judgment, expects to be finally recoverable in
respect thereof have been so recovered. The Master Servicer shall maintain
records, prepared by a Servicing Officer, of each Final Recovery Determination
made thereby.

                  "Fitch": Fitch Ratings, or its successor in interest.

                  "Fixed-Rate Mortgage Loan": Each of the Mortgage Loans
identified in the Mortgage Loan Schedule as having a Mortgage Rate that is
fixed.

                  "Formula Rate": For any Distribution Date and the Class A-1
Certificates and the Mezzanine Certificates (other than the Class MF-5
Certificates), the lesser of (i) One-Month LIBOR plus the related Certificate
Margin and (ii) the Maximum Cap Rate.

                  For any Distribution Date and the Class A-2 Certificates, the
lesser of (i) One-Month LIBOR plus the related Certificate Margin and (ii)
beginning on the 22nd Distribution Date, the Maximum Cap Rate.

                  "Freddie Mac": Freddie Mac, formally known as the Federal Home
Loan Mortgage Corporation, or any successor thereto.

                  "Gross Margin": With respect to each Adjustable-Rate Mortgage
Loan, the fixed percentage set forth in the related Mortgage Note that is added
to the Index on each Adjustment Date in accordance with the terms of the related
Mortgage Note used to determine the Mortgage Rate for such Adjustable-Rate
Mortgage Loan.

                                      -13-

<PAGE>

                  "Group I Allocation Percentage": With respect to any
Distribution Date, the percentage equivalent of a fraction, the numerator of
which is (i) the Group I Principal Remittance Amount for such Distribution Date,
and the denominator of which is (ii) the Principal Remittance Amount for such
Distribution Date.

                  "Group I Basic Principal Distribution Amount": With respect to
any Distribution Date, the excess of (i) the Group I Principal Remittance Amount
for such Distribution Date over (ii)(a) the Overcollateralization Release
Amount, if any, for such Distribution Date multiplied by (b) the Group I
Allocation Percentage.

                  "Group I Interest Remittance Amount": With respect to any
Distribution Date, that portion of the Available Funds for such Distribution
Date attributable to interest received or advanced with respect to the Group I
Mortgage Loans.

                  "Group I Mortgage Loan": A Mortgage Loan assigned to Loan
Group I with a principal balance that conforms to Fannie Mae and Freddie Mac
guidelines.

                  "Group I Principal Distribution Amount": With respect to any
Distribution Date, the sum of (i) the Group I Basic Principal Distribution
Amount for such Distribution Date and (ii)(a) the Extra Principal Distribution
Amount for such Distribution Date multiplied by (b) the Group I Allocation
Percentage.

                  "Group I Principal Remittance Amount": With respect to any
Distribution Date, the sum of (i) each scheduled payment of principal collected
or advanced on the Group I Mortgage Loans by the Master Servicer that were due
during the related Due Period, (ii) the principal portion of all partial and
full principal prepayments of the Group I Mortgage Loans applied by the Master
Servicer during the related Prepayment Period, (iii) the principal portion of
all related Net Liquidation Proceeds and Insurance Proceeds received during such
Prepayment Period with respect to the Group I Mortgage Loans, (iv) that portion
of the Purchase Price, representing principal of any repurchased Group I
Mortgage Loan, deposited to the Collection Account during such Prepayment
Period, (v) the principal portion of any related Substitution Adjustment Amounts
deposited in the Collection Account during such Prepayment Period with respect
to the Group I Mortgage Loans and (vi) on the Distribution Date on which the
Trust Fund is to be terminated pursuant to Section 9.01, that portion of the
Termination Price, in respect of principal on the Group I Mortgage Loans.

                  "Group II Allocation Percentage": With respect to any
Distribution Date, the percentage equivalent of a fraction, the numerator of
which is (i) the Group II Principal Remittance Amount for such Distribution
Date, and the denominator of which is (ii) the Principal Remittance Amount for
such Distribution Date.

                  "Group II Basic Principal Distribution Amount": With respect
to any Distribution Date, the excess of (i) the Group II Principal Remittance
Amount for such Distribution Date over (ii)(a) the Overcollateralization Release
Amount, if any, for such Distribution Date multiplied by (b) the Group II
Allocation Percentage.

                  "Group II Interest Remittance Amount": With respect to any
Distribution Date, that

                                      -14-

<PAGE>

portion of the Available Funds for such Distribution Date attributable to
interest received or advanced with respect to the Group II Mortgage Loans.

                  "Group II Mortgage Loan": A Mortgage Loan assigned to Loan
Group II with a principal balance that may or may not conform to Fannie Mae and
Freddie Mac guidelines.

                  "Group II Principal Distribution Amount": With respect to any
Distribution Date, the sum of (i) the Group II Basic Principal Distribution
Amount for such Distribution Date and (ii)(a) the Extra Principal Distribution
Amount for such Distribution Date multiplied by (b) the Group II Allocation
Percentage.

                  "Group II Principal Remittance Amount": With respect to any
Distribution Date, the sum of (i) each scheduled payment of principal collected
or advanced on the Group II Mortgage Loans by the Master Servicer that were due
during the related Due Period, (ii) the principal portion of all partial and
full principal prepayments of the Group II Mortgage Loans applied by the Master
Servicer during the related Prepayment Period, (iii) the principal portion of
all related Net Liquidation Proceeds and Insurance Proceeds received during such
Prepayment Period with respect to the Group II Mortgage Loans, (iv) that portion
of the Purchase Price, representing principal of any repurchased Group II
Mortgage Loan, deposited to the Collection Account during such Prepayment
Period, (v) the principal portion of any related Substitution Adjustment Amounts
deposited in the Collection Account during such Prepayment Period with respect
to the Group II Mortgage Loans and (vi) on the Distribution Date on which the
Trust Fund is to be terminated pursuant to Section 9.01, that portion of the
Termination Price, in respect of principal on the Group II Mortgage Loans.

                  "Indenture": An indenture relating to the issuance of notes
secured by the Class CE Certificates, the Class P Certificates and/or the Class
R Certificates (or any portion thereof) which may or may not be guaranteed by
the NIMS Insurer.

                  "Independent": When used with respect to any specified Person,
any such Person who (a) is in fact independent of the Depositor, the Seller, the
Master Servicer, the Originator and their respective Affiliates, (b) does not
have any direct financial interest in or any material indirect financial
interest in the Depositor, the Seller, the Originator, the Master Servicer or
any Affiliate thereof, and (c) is not connected with the Depositor, the Seller,
the Originator, the Master Servicer or any Affiliate thereof as an officer,
employee, promoter, underwriter, trustee, partner, director or Person performing
similar functions; provided, however, that a Person shall not fail to be
Independent of the Depositor, the Seller, the Originator, the Master Servicer or
any Affiliate thereof merely because such Person is the beneficial owner of 1%
or less of any class of securities issued by the Depositor, the Seller, the
Originator, the Master Servicer or any Affiliate thereof, as the case may be.

                  "Independent Contractor": Either (i) any Person (other than
the Master Servicer) that would be an "independent contractor" with respect to
REMIC I within the meaning of Section 856(d)(3) of the Code if REMIC I were a
real estate investment trust (except that the ownership tests set forth in that
section shall be considered to be met by any Person that owns, directly or
indirectly, 35% or more of any Class of Certificates), so long as REMIC I does
not receive or derive any income from such Person and provided that the
relationship between such Person and REMIC I is at arm's

                                      -15-

<PAGE>

length, all within the meaning of Treasury Regulation Section 1.856-4(b)(5), or
(ii) any other Person (including the Master Servicer) if the Trustee has
received an Opinion of Counsel to the effect that the taking of any action in
respect of any REO Property by such Person, subject to any conditions therein
specified, that is otherwise herein contemplated to be taken by an Independent
Contractor will not cause such REO Property to cease to qualify as "foreclosure
property" within the meaning of Section 860G(a)(8) of the Code (determined
without regard to the exception applicable for purposes of Section 860D(a) of
the Code), or cause any income realized in respect of such REO Property to fail
to qualify as Rents from Real Property.

                  "Index": With respect to each Adjustable Rate Mortgage Loan
and with respect to each related Adjustment Date, the index as specified in the
related Mortgage Note.

                  "Insurance Proceeds": Proceeds of any title policy, hazard
policy or other insurance policy, including the PMI Policy, covering a Mortgage
Loan, to the extent such proceeds are not to be applied to the restoration of
the related Mortgaged Property or released to the Mortgagor in accordance with
the procedures that the Master Servicer would follow in servicing mortgage loans
held for its own account, subject to the terms and conditions of the related
Mortgage Note and Mortgage.

                  "Interest Determination Date": With respect to the Class A
Certificates, the Mezzanine Certificates (other than the Class MF-5
Certificates), REMIC I Regular Interest I-LTA1, REMIC I Regular Interest I-LTA2,
REMIC I Regular Interest I-LTM1, REMIC I Regular Interest I-LTM2, REMIC I
Regular Interest I-LTM3, REMIC I Regular Interest I-LTM4 and REMIC I Regular
Interest I-LTMV5 and any Accrual Period therefor, the second London Business Day
preceding the commencement of such Accrual Period.

                  "Late Collections": With respect to any Mortgage Loan and any
Due Period, all amounts received subsequent to the Determination Date
immediately following such Due Period, whether as late payments of Monthly
Payments or as Insurance Proceeds, Liquidation Proceeds or otherwise, which
represent late payments or collections of principal and/or interest due (without
regard to any acceleration of payments under the related Mortgage and Mortgage
Note) but delinquent for such Due Period and not previously recovered.

                  "Liquidated Mortgage Loan": As to any Distribution Date, any
Mortgage Loan in respect of which the Master Servicer has determined, in
accordance with the servicing procedures specified herein, as of the end of the
related Prepayment Period, that all Liquidation Proceeds which it expects to
recover with respect to the liquidation of the Mortgage Loan or disposition of
the related REO Property have been recovered.

                  "Liquidation Event": With respect to any Mortgage Loan, any of
the following events: (i) such Mortgage Loan is paid in full; (ii) a Final
Recovery Determination is made as to such Mortgage Loan; or (iii) such Mortgage
Loan is removed from REMIC I by reason of its being purchased, sold or replaced
pursuant to or as contemplated by Section 2.03, Section 3.16(c) or Section 9.01.
With respect to any REO Property, either of the following events: (i) a Final
Recovery Determination is made as to such REO Property; or (ii) such REO
Property is removed from REMIC I by reason of its being purchased pursuant to
Section 9.01.

                                      -16-

<PAGE>

                  "Liquidation Proceeds": The amount (other than amounts
received in respect of the rental of any REO Property prior to REO Disposition)
received by the Master Servicer in connection with (i) the taking of all or a
part of a Mortgaged Property by exercise of the power of eminent domain or
condemnation, (ii) the liquidation of a defaulted Mortgage Loan through a
trustee's sale, foreclosure sale or otherwise, or (iii) the repurchase,
substitution or sale of a Mortgage Loan or an REO Property pursuant to or as
contemplated by Section 2.03, Section 3.16(c), Section 3.23 or Section 9.01.

                  "Loan-to-Value Ratio": As of any date of determination, the
fraction, expressed as a percentage, the numerator of which is the principal
balance of the related Mortgage Loan at such date and the denominator of which
is the Value of the related Mortgaged Property.

                  "Loan Group": Either Loan Group I or Loan Group II, as the
context requires.

                  "Loan Group I": The group of Mortgage Loans identified in the
Mortgage Loan Schedule as having been assigned to Loan Group I.

                  "Loan Group II": The group of Mortgage Loans identified in the
Mortgage Loan Schedule as having been assigned to Loan Group II.

                  "London Business Day": Any day on which banks in the City of
London are open and conducting transactions in United States dollars.

                  "Loss Mitigation Procedures": The policies and procedures set
forth in Exhibit K hereto relating to the realization on delinquent Mortgage
Loans.

                  "Loss Severity Percentage": With respect to any Distribution
Date, the percentage equivalent of a fraction, the numerator of which is the
amount of Realized Losses incurred on a Mortgage Loan and the denominator of
which is the principal balance of such Mortgage Loan immediately prior to the
liquidation of such Mortgage Loan.

                  "Marker Rate": With respect to the Class CE Certificates and
any Distribution Date, a per annum rate equal to two (2) times the weighted
average of the REMIC I Remittance Rate for each of REMIC I Regular Interest
I-LTA1, I-LTA2, I-LTM1, I-LTM2, I-LTM3, I-LTM4, I-LTMF5, I-LTMV5 and I-LTZZ,
with the rate on each such REMIC I Regular Interest subject to a cap equal to
the related Formula Rate or Pass-Through Rate (in the case of REMIC I Regular
Interest I- LTMF5) for the purpose of this calculation for such Distribution
Date and with the rate on REMIC I Regular Interest I-LTZZ subject to a cap of
zero for the purpose of this calculation; provided, however, that solely for
this purpose, calculations of the REMIC I Remittance Rate and the related caps
with respect to such REMIC I Regular Interests (other than REMIC I Regular
Interest I-LTMF5 and REMIC I Regular Interest I-LTZZ) shall be multiplied by a
fraction, the numerator of which is the actual number of days in the Interest
Accrual Period and the denominator of which is 30.

                  "Master Servicer": Option One Mortgage Corporation or any
successor master servicer appointed as herein provided, in its capacity as
Master Servicer hereunder.

                                      -17-

<PAGE>

                  "Master Servicer Event of Default": One or more of the events
described in Section 7.01.

                  "Master Servicer Optional Purchase Delinquency Trigger": A
Master Servicer Optional Purchase Delinquency Trigger has occurred with respect
to a Distribution Date if the Delinquency Percentage exceeds 14.00% of the
Credit Enhancement Percentage.

                  "Master Servicer Prepayment Charge Payment Amount": The
amounts payable by the Master Servicer in respect of any Prepayment Charges
pursuant to Section 2.05 or Section 3.01.

                  "Master Servicer Remittance Date": With respect to any
Distribution Date, by 1:00 p.m. New York time the Business Day immediately
preceding the related Distribution Date.

                  "Maximum Cap Rate": For any Distribution Date with respect to
the Class A-1 Certificates, a per annum rate equal to the product of (x) the
weighted average of the Adjusted Net Maximum Mortgage Rates of the Group I
Mortgage Loans, weighted based on their outstanding Principal Balances as of the
first day of the calendar month preceding the month in which the Distribution
Date occurs and (y) a fraction, the numerator of which is 30 and the denominator
of which is the actual number of days elapsed in the related Accrual Period.

                  For any Distribution Date with respect to the Class A-2
Certificates, a per annum rate equal to the product of (x) the weighted average
of the Adjusted Net Maximum Mortgage Rates of the Group II Mortgage Loans,
weighted based on their outstanding Principal Balances as of the first day of
the calendar month preceding the month in which the Distribution Date occurs and
(y) a fraction, the numerator of which is 30 and the denominator of which is the
actual number of days elapsed in the related Accrual Period.

                  For any Distribution Date with respect to the Mezzanine
Certificates (other than the Class MF-5 Certificates), a per annum rate equal to
the product of (x) the weighted average of the Adjusted Net Maximum Mortgage
Rates of the Group I Mortgage Loans and the Group II Mortgage Loans, weighted in
proportion to the results of subtracting from the aggregate Principal Balance of
each Loan Group the current Certificate Principal Balance of the related Class A
Certificates, weighted based on their outstanding Principal Balances as of the
first day of the calendar month preceding the month in which the Distribution
Date occurs and (y) a fraction, the numerator of which is 30 and the denominator
of which is the actual number of days elapsed in the related Accrual Period.

                  "Maximum I-LTZZ Uncertificated Interest Deferral Amount": With
respect to any Distribution Date, the excess of (i) accrued interest at the
REMIC I Remittance Rate applicable to REMIC I Regular Interest I-LTZZ for such
Distribution Date on a balance equal to the Uncertificated Balance of REMIC I
Regular Interest I-LTZZ minus the REMIC I Overcollateralization Amount, in each
case for such Distribution Date, over (ii) Uncertificated Interest on REMIC I
Regular Interest I-LTA1, REMIC I Regular Interest I-LTA2, REMIC I Regular
Interest I-LTM1, REMIC I Regular Interest I-LTM2, REMIC I Regular Interest
I-LTM3, REMIC I Regular Interest I-LTM4, REMIC I Regular Interest I-LTMV5 and
REMIC I Regular Interest I-LTMF5 for such Distribution Date, with

                                      -18-

<PAGE>

(A) the rate on REMIC I Regular Interest I-LTA1, REMIC I Regular Interest
I-LTA2, REMIC I Regular Interest I-LTM1, REMIC I Regular Interest I-LTM2, REMIC
I Regular Interest I-LTM3, REMIC I Regular Interest I-LTM4 and REMIC I Regular
Interest I-LTMV5 subject to a cap equal to the related Formula Rate; provided,
however, each cap shall be multiplied by a fraction, the numerator of which is
the actual number of days in the related Interest Accrual Period and the
denominator of which is 30; and (B) the rate on REMIC I Regular Interest
I-LTMF5, subject to a cap equal to the related Pass-Through Rate.

                  "Maximum Mortgage Rate": With respect to each Adjustable-Rate
Mortgage Loan, the percentage set forth in the related Mortgage Note as the
maximum Mortgage Rate thereunder.

                  "Mezzanine Certificate": Any Class M-1 Certificate, Class M-2
Certificate, Class M- 3 Certificate, Class M-4 Certificate, Class MV-5
Certificate or Class MF-5 Certificate.

                  "Minimum Mortgage Rate": With respect to each Adjustable-Rate
Mortgage Loan, the percentage set forth in the related Mortgage Note as the
minimum Mortgage Rate thereunder.

                  "Monthly Interest Distributable Amount": With respect to the
Class A Certificates, the Mezzanine Certificates and the Class CE Certificates
and any Distribution Date, the amount of interest accrued during the related
Accrual Period at the related Pass-Through Rate on the Certificate Principal
Balance (or Notional Amount in the case of the Class CE Certificates) of such
Class immediately prior to such Distribution Date, reduced by any Prepayment
Interest Shortfalls (to the extent not covered by payments made by the Master
Servicer pursuant to Section 3.24) and Relief Act Interest Shortfalls (allocated
to such Certificate based on its respective entitlements to interest
irrespective of any Prepayment Interest Shortfalls and Relief Act Interest
Shortfalls for such Distribution Date).

                  "Monthly Payment": With respect to any Mortgage Loan, the
scheduled monthly payment of principal and interest on such Mortgage Loan which
is payable by the related Mortgagor from time to time under the related Mortgage
Note, determined: (a) after giving effect to (i) any Deficient Valuation and/or
Debt Service Reduction with respect to such Mortgage Loan and (ii) any reduction
in the amount of interest collectible from the related Mortgagor pursuant to the
Relief Act; (b) without giving effect to any extension granted or agreed to by
the Master Servicer pursuant to Section 3.07 and (c) on the assumption that all
other amounts, if any, due under such Mortgage Loan are paid when due.

                  "Monthly Statement": The statement prepared by the Trustee
pursuant to Section 4.02.

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

                  "Mortgage": The mortgage, deed of trust or other instrument
creating a first or second lien on, or first or second priority security
interest in, a Mortgaged Property securing a Mortgage Note.

                  "Mortgage File": The mortgage documents listed in Section 2.01
pertaining to a

                                      -19-

<PAGE>

particular Mortgage Loan and any additional documents required to be added to
the Mortgage File pursuant to this Agreement.

                  "Mortgage Loan": Each mortgage loan transferred and assigned
to the Trustee and delivered to the Trustee pursuant to Section 2.01 or Section
2.03(b) of this Agreement, as held from time to time as a part of the Trust, the
Mortgage Loans so held being identified in the Mortgage Loan Schedule.

                  "Mortgage Loan Purchase Agreement": The agreement among the
Seller, the Originator and the Depositor, regarding the sale of the Mortgage
Loans by the Seller to the Depositor, substantially in the form of Exhibit D
annexed hereto.

                  "Mortgage Loan Schedule": As of any date, the list of Mortgage
Loans included in REMIC I on such date, attached hereto as Schedule 1. The
Mortgage Loan Schedule shall set forth the following information with respect to
each Mortgage Loan:

                  (1)      the Mortgage Loan identifying number;

                  (2)      the Mortgagor's name;

                  (3)      the street address of the Mortgaged Property
         including the state and zip code;

                  (4)      a code indicating whether the Mortgaged Property was
         represented by the borrower, at the time of origination, as being
         owner-occupied;

                  (5)      the type of Residential Dwelling constituting the
         Mortgaged Property;

                  (6)      the original months to maturity;

                  (7)      the stated remaining months to maturity from the
         Cut-off Date based on the original amortization schedule;

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

                  (9)      the Mortgage Rate in effect immediately following the
         Cut-off Date;

                  (10)     the date on which the first Monthly Payment was due
         on the Mortgage Loan;

                  (11)     the stated maturity date;

                  (12)     the amount of the Monthly Payment at origination;

                  (13)     the amount of the Monthly Payment due on the first
         Due Date after the Cut- off Date;

                  (14)     the last Due Date on which a Monthly Payment was
         actually applied to the

                                      -20-

<PAGE>

         unpaid Stated Principal Balance;

                  (15)     the original principal amount of the Mortgage Loan;

                  (16)     the Stated Principal Balance of the Mortgage Loan as
         of the close of business on the Cut-off Date;

                  (17)     a code indicating the purpose of the Mortgage Loan
         (I.E., purchase financing, rate/term refinancing, cash-out
         refinancing);

                  (18)     the Mortgage Rate at origination;

                  (19)     a code indicating the documentation program (I.E.,
         full documentation, limited documentation, stated income
         documentation);

                  (20)     the risk grade;

                  (21)     the Value of the Mortgaged Property;

                  (22)     the sale price of the Mortgaged Property, if
         applicable;

                  (23)     the actual unpaid principal balance of the Mortgage
         Loan as of the Cut-off Date;

                  (24)     the type and term of the related Prepayment Charge;

                  (25)     the rounding code;

                  (26)     the program code;

                  (27)     a code indicating the lien priority for Mortgage
         Loans;

                  (28)     with respect to each Adjustable Rate Mortgage Loan,
         the Minimum Mortgage Rate;

                  (29)     with respect to each Adjustable Rate Mortgage Loan,
         the Maximum Mortgage Rate;

                  (30)     with respect to each Adjustable Rate Mortgage Loan,
         the Gross Margin;

                  (31)     with respect to each Adjustable Rate Mortgage Loan,
         the next Adjustment Date;

                  (32)     with respect to each Adjustable Rate Mortgage Loan,
         the Periodic Rate Cap;

                  (33)     whether such Mortgage Loan is covered under the PMI
         Policy; and

                                      -21-

<PAGE>

                  (34)     the credit score ("FICO") of such Mortgage Loan.

                  The Mortgage Loan Schedule shall set forth the following
information with respect to the Mortgage Loans in the aggregate and for each
Loan Group as of the Cut-off Date: (1) the number of Mortgage Loans (separately
identifying the number of Fixed-Rate Mortgage Loans and the number of
Adjustable-Rate Mortgage Loans); (2) the current Principal Balance of the
Mortgage Loans; (3) the weighted average Mortgage Rate of the Mortgage Loans and
(4) the weighted average maturity of the Mortgage Loans. The Mortgage Loan
Schedule shall be amended from time to time by the Depositor in accordance with
the provisions of this Agreement. With respect to any Qualified Substitute
Mortgage Loan, the Cut-off Date shall refer to the related Cut-off Date for such
Mortgage Loan, determined in accordance with the definition of Cut-off Date
herein.

                  "Mortgage Note": The original executed note or other evidence
of the indebtedness of a Mortgagor under a Mortgage Loan.

                  "Mortgage Pool": The pool of Mortgage Loans, identified on
Schedule 1 and existing from time to time thereafter, and any REO Properties
acquired in respect thereof.

                  "Mortgage Rate": With respect to each Mortgage Loan, the
annual rate at which interest accrues on such Mortgage Loan from time to time in
accordance with the provisions of the related Mortgage Note, which rate with
respect to the Adjustable-Rate Mortgage Loans, (A) as of any date of
determination until the first Adjustment Date following the Cut-off Date shall
be the rate set forth in the Mortgage Loan Schedule as the Mortgage Rate in
effect immediately following the Cut-off Date and (B) as of any date of
determination thereafter shall be the rate as adjusted on the most recent
Adjustment Date equal to the sum, rounded to the nearest or next highest 0.125%
as provided in the Mortgage Note, of the Index, as most recently available as of
a date prior to the Adjustment Date as set forth in the related Mortgage Note,
plus the related Gross Margin; provided that the Mortgage Rate on such
Adjustable-Rate Mortgage Loan on any Adjustment Date shall never be more than
the lesser of (i) the sum of the Mortgage Rate in effect immediately prior to
the Adjustment Date plus the related Periodic Rate Cap, if any, and (ii) the
related Maximum Mortgage Rate, and shall never be less than the greater of (i)
the Mortgage Rate in effect immediately prior to the Adjustment Date less the
Periodic Rate Cap, if any, and (ii) the related Minimum Mortgage Rate. With
respect to each Mortgage Loan that becomes an REO Property, as of any date of
determination, the annual rate determined in accordance with the immediately
preceding sentence as of the date such Mortgage Loan became an REO Property.

                  "Mortgaged Property": The underlying property securing a
Mortgage Loan, including any REO Property, consisting of an Estate in Real
Property improved by a Residential Dwelling.

                  "Mortgagor": The obligor on a Mortgage Note.

                  "Net Liquidation Proceeds": With respect to any Liquidated
Mortgage Loan or any other disposition of related Mortgaged Property (including
REO Property) the related Liquidation Proceeds and Insurance Proceeds net of
Advances, Servicing Advances, Servicing Fees and any other accrued and unpaid
servicing fees received and retained in connection with the liquidation of such
Mortgage Loan or Mortgaged Property.

                                      -22-

<PAGE>

                  "Net Monthly Excess Cashflow": With respect to each
Distribution Date, the sum of (a) any Overcollateralization Release Amount for
such Distribution Date and (b) the excess of (x) Available Funds for such
Distribution Date over (y) the sum for such Distribution Date of (A) the Monthly
Interest Distributable Amounts for the Class A Certificates and the Mezzanine
Certificates, (B) the Unpaid Interest Shortfall Amounts for the Class A
Certificates and (C) the Principal Remittance Amount.

                  "Net Mortgage Rate": With respect to any Mortgage Loan (or the
related REO Property) as of any date of determination, a per annum rate of
interest equal to the then applicable Mortgage Rate for such Mortgage Loan minus
the Servicing Fee Rate.

                  "Net WAC Rate": For any Distribution Date with respect to the
Class A-1 Certificates, a per annum rate equal to the product of (x) the
weighted average of the Adjusted Net Mortgage Rates of the Group I Mortgage
Loans, weighted based on their outstanding Principal Balances as of the first
day of the calendar month preceding the month in which the Distribution Date
occurs and (y) a fraction, the numerator of which is 30 and the denominator of
which is the actual number of days elapsed in the related Accrual Period. For
federal income tax purposes, the economic equivalent of such rate shall be
expressed as the weighted average of the REMIC I Remittance Rate on REMIC I
Regular Interest I-LT1GRP, weighted on the basis of the Uncertificated Balance
of such REMIC I Regular Interest.

                  For any Distribution Date with respect to the Class A-2
Certificates, a per annum rate equal to the product of (x) the weighted average
of the Adjusted Net Mortgage Rates of the Group II Mortgage Loans, weighted
based on their outstanding Principal Balances as of the first day of the
calendar month preceding the month in which the Distribution Date occurs and (y)
a fraction, the numerator of which is 30 and the denominator of which is the
actual number of days elapsed in the related Accrual Period. For federal income
tax purposes, the economic equivalent of such rate shall be expressed as the
weighted average of the REMIC I Remittance Rate on REMIC I Regular Interest
I-LT2GRP, weighted on the basis of the Uncertificated Balance of such REMIC I
Regular Interest.

                  For any Distribution Date with respect to the Mezzanine
Certificates, a per annum rate equal to the product of (x) the weighted average
of the Adjusted Net Mortgage Rates of the Group I Mortgage Loans and the Group
II Mortgage Loans, weighted in proportion to the results of subtracting from the
aggregate Stated Principal Balance of each Loan Group the Certificate Principal
Balance of the related Class of Class A Certificates and (y) for each Class of
Mezzanine Certificates (other than the Class MF-5 Certificates) a fraction, the
numerator of which is 30 and the denominator of which is the actual number of
days elapsed in the related Accrual Period. For federal income tax purposes, the
economic equivalent of such rate shall be expressed as the weighted average of
the REMIC I Remittance Rates on (a) REMIC I Regular Interest I-LT1SUB, subject
to a cap and a floor equal to the Adjusted Net Mortgage Rates of the Group I
Mortgage Loans and (b) REMIC I Regular Interest I-LT2SUB, subject to a cap and a
floor equal to the Adjusted Net Mortgage Rates of the Group II Mortgage Loans,
weighted on the basis of the Uncertificated Balance of each such REMIC I Regular
Interest.

                  "Net WAC Rate Carryover Amount": With respect to the Class A
Certificates and the Mezzanine Certificates and any Distribution Date, the sum
of (A) the positive excess of (i) the

                                      -23-

<PAGE>

amount of interest accrued on such Class of Certificates on such Distribution
Date calculated at the related Formula Rate (in the case of the Class A
Certificates and Mezzanine Certificates other than the Class MF-5 Certificates)
or the fixed rate (in the case of the Class MF-5 Certificates), over (ii) the
amount of interest accrued on such Class of Certificates at the Net WAC Rate for
such Distribution Date and (B) the Net WAC Rate Carryover Amount for the
previous Distribution Date not previously paid, together with interest thereon
at a rate equal to the Formula Rate (in the case of the Class A Certificates and
Mezzanine Certificates other than the Class MF-5 Certificates) or the fixed rate
(in the case of the Class MF-5 Certificates) for such Class of Certificates for
such Distribution Date and for such Accrual Period.

                  "Net WAC Rate Carryover Reserve Account": The account
established and maintained pursuant to Section 3.28.

                  "New Lease": Any lease of REO Property entered into on behalf
of REMIC I, including any lease renewed or extended on behalf of REMIC I, if
REMIC I has the right to renegotiate the terms of such lease.

                  "NIMS Insurer": Any insurer that is guaranteeing certain
payments under notes secured by collateral which includes all or a portion of
the Class CE Certificates, the Class P Certificates and/or the Class R
Certificates.

                  "Nonrecoverable Advance": Any Advance previously made or
proposed to be made in respect of a Mortgage Loan or REO Property that, in the
good faith business judgment of the Master Servicer, will not or, in the case of
a proposed Advance, would not be ultimately recoverable from related Late
Collections, Insurance Proceeds or Liquidation Proceeds on such Mortgage Loan or
REO Property as provided herein.

                  "Nonrecoverable Servicing Advance": Any Servicing Advance
previously made or proposed to be made in respect of a Mortgage Loan or REO
Property that, in the good faith business judgment of the Master Servicer, will
not or, in the case of a proposed Servicing Advance, would not be ultimately
recoverable from related Late Collections, Insurance Proceeds or Liquidation
Proceeds on such Mortgage Loan or REO Property as provided herein.

                  "Non-United States Person": Any Person other than a United
States Person.

                  "Notional Amount": With respect to the Class CE Certificates
and any Distribution Date, the Uncertificated Balance of the REMIC I Regular
Interests for such Distribution Date.

                  "Officers'Certificate": A certificate signed by the Chairman
of the Board, the Vice Chairman of the Board, the President or a vice president
(however denominated), and by the Treasurer, the Secretary, or one of the
assistant treasurers or assistant secretaries of the Master Servicer, the
Originator, the Seller or the Depositor, as applicable.

                  "One-Month LIBOR": With respect to the Class A Certificates,
the Mezzanine Certificates (other than the Class MF-5 Certificates), REMIC I
Regular Interest I-LTA1, REMIC I Regular Interest I-LTA2, REMIC I Regular
Interest I-LTM1, REMIC I Regular Interest I-LTM2,

                                      -24-

<PAGE>

REMIC I Regular Interest I-LTM3, REMIC I Regular Interest I-LTM4 and REMIC I
Regular Interest I-LTMV5 and any Accrual Period therefor, the rate determined by
the Trustee on the related Interest Determination Date on the basis of the
offered rate for one-month U.S. dollar deposits, as such rate appears on
Telerate Page 3750 as of 11:00 a.m. (London time) on such Interest Determination
Date; provided that if such rate does not appear on Telerate Page 3750, the rate
for such date will be determined on the basis of the offered rates of the
Reference Banks for one-month U.S. dollar deposits, as of 11:00 a.m. (London
time) on such Interest Determination Date. In such event, the Trustee will
request the principal London office of each of the Reference Banks to provide a
quotation of its rate. If on such Interest Determination Date, two or more
Reference Banks provide such offered quotations, One-Month LIBOR for the related
Accrual Period shall be the arithmetic mean of such offered quotations (rounded
upwards if necessary to the nearest whole multiple of 1/16%). If on such
Interest Determination Date, fewer than two Reference Banks provide such offered
quotations, One-Month LIBOR for the related Accrual Period shall be the higher
of (i) LIBOR as determined on the previous Interest Determination Date and (ii)
the Reserve Interest Rate. Notwithstanding the foregoing, if, under the
priorities described above, LIBOR for an Interest Determination Date would be
based on LIBOR for the previous Interest Determination Date for the third
consecutive Interest Determination Date, the Trustee shall select, after
consultation with the NIMS Insurer, an alternative comparable index (over which
the Trustee has no control), used for determining one-month Eurodollar lending
rates that is calculated and published (or otherwise made available) by an
independent party.

                  "Opinion of Counsel": A written opinion of counsel, who may,
without limitation, be salaried counsel for the Depositor or the Master
Servicer, acceptable to the Trustee, except that any opinion of counsel relating
to (a) the qualification of any of Trust REMIC as a REMIC or (b) compliance with
the REMIC Provisions must be an opinion of Independent counsel.

                  "Original Mortgage Loan": Any of the Mortgage Loans included
in REMIC I as of the Closing Date.

                  "Originator": Option One Mortgage Corporation.

                  "Overcollateralization Deficiency Amount": With respect to any
Distribution Date, the amount, if any, by which the Overcollateralization Target
Amount exceeds the Overcollateralized Amount on such Distribution Date (after
giving effect to distributions in respect of the Group I Basic Principal
Distribution Amount and the Group II Basic Principal Distribution Amount on such
Distribution Date).

                  "Overcollateralization Release Amount": With respect to any
Distribution Date, the lesser of (x) the Principal Remittance Amount for such
Distribution Date and (y) the Excess Overcollateralized Amount.

                  "Overcollateralization Target Amount": With respect to any
Distribution Date, (i) 0.75% of the Cut-off Date Principal Balance of the
Mortgage Loans, (ii) on or after the Stepdown Date provided a Trigger Event is
not in effect, the greater of (x) 1.50% of the aggregate Stated Principal
Balance of the Mortgage Loans as of the last day of the related Due Period
(after giving effect to scheduled payments of principal due during the related
Due Period, to the extent received

                                      -25-

<PAGE>

or advanced, and unscheduled collections of principal received during the
related Prepayment Period) and (y) $7,320,007, or (iii) on or after the Stepdown
Date if a Trigger Event is in effect, the Overcollateralization Target Amount
for the immediately preceding Distribution Date.

                  "Overcollateralized Amount": For any Distribution Date, the
amount equal to (i) the aggregate Principal Balance of the Mortgage Loans as of
the last day of the related Due Period (after giving effect to scheduled
payments of principal due during the related Due Period, to the extent received
or advanced, and unscheduled collections of principal received during the
related Prepayment Period) as of the related Determination Date minus (ii) the
sum of the aggregate Certificate Principal Balance of the Class A Certificates,
the Mezzanine Certificates and the Class P Certificates as of such Distribution
Date after giving effect to distributions to be made on such Distribution Date.

                  "Ownership Interest": As to any Certificate, any ownership or
security interest in such Certificate, including any interest in such
Certificate as the Holder thereof and any other interest therein, whether direct
or indirect, legal or beneficial, as owner or as pledgee.

                  "Pass-Through Rate": With respect to the Class A Certificates
and the Mezzanine Certificates (other than the Class MF-5 Certificates) and any
Distribution Date, a rate per annum equal to the lesser of (i) the related
Formula Rate for such Distribution Date and (ii) the Net WAC Rate for such
Distribution Date.

                  With respect to the Class MF-5 Certificates and each
Distribution Date through and including the Distribution Date on which the
aggregate Principal Balance of the Mortgage Loans (and properties acquired in
respect thereof) remaining in the Trust Fund is reduced to less than 10% of the
aggregate Cut-off Date Principal Balance of the Mortgage Loans, the lesser of
(x) 6.000% per annum and (y) the Net WAC Rate for such class for such
Distribution Date and in the case of each Distribution Date thereafter will
equal the lesser of (x) 6.50% per annum on each Distribution Date and (y) the
Net WAC Rate for such Distribution Date.

                  With respect to the Class CE Certificates and any Distribution
Date, a rate per annum equal to the percentage equivalent of a fraction, the
numerator of which is the sum of the amounts calculated pursuant to clauses (A)
through (K) below, and the denominator of which is the aggregate Uncertificated
Balance of REMIC I Regular Interest I-LTAA, I-LTA1, I-LTA2, I-LTM1, I-LTM2,
I-LTM3, I-LTM4, I-LTMF5, I-LTMV5, I-LTMZZ and I-LTP. For purposes of calculating
the Pass- Through Rate for the Class CE Certificates, the numerator is equal to
the sum of the following components:

                  (A) the REMIC I Remittance Rate for REMIC I Regular Interest
         I-LTAA minus the Marker Rate, applied to an amount equal to the
         Uncertificated Balance of REMIC I Regular Interest I-LTAA;

                  (B) the REMIC I Remittance Rate for REMIC I Regular Interest
         I-LTA1 minus the Marker Rate, applied to an amount equal to the
         Uncertificated Balance of REMIC I Regular Interest I-LTA1;

                                      -26-

<PAGE>

                  (C) the REMIC I Remittance Rate for REMIC I Regular Interest
         I-LTA2 minus the Marker Rate, applied to an amount equal to the
         Uncertificated Balance of REMIC I Regular Interest I-LTA2;

                  (D) the REMIC I Remittance Rate for REMIC I Regular Interest
         I-LTM1 minus the Marker Rate, applied to an amount equal to the
         Uncertificated Balance of REMIC I Regular Interest I-LTM1;

                  (E) the REMIC I Remittance Rate for REMIC I Regular Interest
         I-LTM2 minus the Marker Rate, applied to an amount equal to the
         Uncertificated Balance of REMIC I Regular Interest I-LTM2;

                  (F) the REMIC I Remittance Rate for REMIC I Regular Interest
         I-LTM3 minus the Marker Rate, applied to an amount equal to the
         Uncertificated Balance of REMIC I Regular Interest I-LTM3;

                  (G) the REMIC I Remittance Rate for REMIC I Regular Interest
         I-LTM4 minus the Marker Rate, applied to an amount equal to the
         Uncertificated Balance of REMIC I Regular Interest I-LTM4;

                  (H) the REMIC I Remittance Rate for REMIC I Regular Interest
         I-LTMV5 minus the Marker Rate, applied to an amount equal to the
         Uncertificated Balance of REMIC I Regular Interest I-LTMV5;

                  (I) the REMIC I Remittance Rate for REMIC I Regular Interest
         I-LTMF5 minus the Marker Rate, applied to an amount equal to the
         Uncertificated Balance of REMIC I Regular Interest I-LTMF5;

                  (J) the REMIC I Remittance Rate for REMIC I Regular Interest
         I-LTZZ minus the Marker Rate, applied to an amount equal to the
         Uncertificated Balance of REMIC I Regular Interest I-LTZZ; and

                  (K) 100% of the interest on REMIC I Regular Interest I-LTP.

                  "Percentage Interest": With respect to any Class of
Certificates (other than the Residual Certificates), the undivided percentage
ownership in such Class evidenced by such Certificate, expressed as a
percentage, the numerator of which is the initial Certificate Principal Balance
or Notional Amount represented by such Certificate and the denominator of which
is the aggregate initial Certificate Principal Balance or Notional Amount of all
of the Certificates of such Class. The Class A Certificates and the Mezzanine
Certificates are issuable only in minimum Percentage Interests corresponding to
minimum initial Certificate Principal Balances of $50,000 and integral multiples
of $1.00 in excess thereof. The Class P Certificates are issuable only in
Percentage Interests corresponding to initial Certificate Principal Balances of
$20 and integral multiples thereof. The Class CE Certificates are issuable only
in minimum Percentage Interests corresponding to minimum initial Certificate
Principal Balances of $10,000 and integral multiples of $1.00 in excess thereof;
provided, however, that a single Certificate of each such Class of Certificates
may be issued

                                      -27-

<PAGE>

having a Percentage Interest corresponding to the remainder of the aggregate
initial Certificate Principal Balance or Notional Amount of such Class or to an
otherwise authorized denomination for such Class plus such remainder. With
respect to any Residual Certificate, the undivided percentage ownership in such
Class evidenced by such Certificate, as set forth on the face of such
Certificate. The Residual Certificates are issuable in Percentage Interests of
20% and multiples thereof.

                  "Periodic Rate Cap": With respect to each Adjustable-Rate
Mortgage Loan and any Adjustment Date therefor, the fixed percentage set forth
in the related Mortgage Note, which is the maximum amount by which the Mortgage
Rate for such Mortgage Loan may increase or decrease (without regard to the
Maximum Mortgage Rate or the Minimum Mortgage Rate) on such Adjustment Date from
the Mortgage Rate in effect immediately prior to such Adjustment Date.

                  "Permitted Investments": Any one or more of the following
obligations or securities acquired at a purchase price of not greater than par,
regardless of whether issued or managed by the Depositor, the Master Servicer,
the NIMS Insurer, the Trustee or any of their respective Affiliates or for which
an Affiliate of the NIMS Insurer or Trustee serves as an advisor:

                  (i) direct obligations of, or obligations fully guaranteed as
         to timely payment of 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) demand and time deposits in, certificates of deposit
         of, bankers' acceptances issued by or federal funds sold by any
         depository institution or trust company (including the Trustee or its
         agent acting in their respective commercial capacities) 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
         authorities, so long as, at the time of such investment or contractual
         commitment providing for such investment, such depository institution
         or trust company (or, if the only Rating Agency is S&P, in the case of
         the principal depository institution in a depository institution
         holding company, debt obligations of the depository institution holding
         company) or its ultimate parent has a short-term uninsured debt rating
         in the highest available rating category of Moody's, Fitch and S&P and
         provided that each such investment has an original maturity of no more
         than 365 days; and provided further that, if the only Rating Agency is
         S&P and if the depository or trust company is a principal subsidiary of
         a bank holding company and the debt obligations of such subsidiary are
         not separately rated, the applicable rating shall be that of the bank
         holding company; and, provided further that, if the original maturity
         of such short-term obligations of a domestic branch of a foreign
         depository institution or trust company shall exceed 30 days, the
         short- term rating of such institution shall be A-1+ in the case of S&P
         if S&P is the Rating Agency; and (B) any other demand or time deposit
         or deposit which is fully insured by the FDIC;

                  (iii) repurchase obligations with a term not to exceed 30 days
         with respect to any security described in clause (i) above and entered
         into with a depository institution or trust company (acting as
         principal) rated A-1+ or higher by S&P, F-1+ or higher by Fitch and A2
         or higher by Moody's, provided, however, that collateral transferred
         pursuant to such repurchase obligation must be of the type described in
         clause (i) above and must (A) be valued daily at current market prices
         plus accrued interest, (B) pursuant to such valuation,

                                      -28-

<PAGE>

         be equal, at all times, to 105% of the cash transferred by the Trustee
         in exchange for such collateral and (C) be delivered to the Trustee or,
         if the Trustee is supplying the collateral, an agent for the Trustee,
         in such a manner as to accomplish perfection of a security interest in
         the collateral by possession of certificated securities;

                  (iv) securities bearing interest or sold at a discount that
         are issued by any corporation incorporated under the laws of the United
         States of America or any State thereof and that are rated by a Rating
         Agency in its highest long-term unsecured rating category at the time
         of such investment or contractual commitment providing for such
         investment;

                  (v) commercial paper (including both non-interest-bearing
         discount obligations and interest-bearing obligations payable on demand
         or on a specified date not more than 30 days after the date of
         acquisition thereof) that is rated by a Rating Agency in its highest
         short- term unsecured debt rating available at the time of such
         investment;

                  (vi) units of money market funds, including those managed or
         advised by the Trustee or its Affiliates, that have been rated "AAA" by
         S&P, "AAA" by Fitch (if so rated by Fitch) and "Aaa" by Moody's; and

                  (vii) if previously confirmed in writing to the Trustee and
         consented to by the NIMS Insurer, any other demand, money market or
         time deposit, or any other obligation, security or investment, as may
         be acceptable to the Rating Agencies in writing as a permitted
         investment of funds backing securities having ratings equivalent to its
         highest initial rating of the Class A Certificates;

provided, that no instrument described hereunder shall evidence either the right
to receive (a) only interest with respect to the obligations underlying such
instrument or (b) 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 par greater than 120% of the
yield to maturity at par of the underlying obligations.

                  "Permitted Transferee": Any Transferee of a Residual
Certificate other than a Disqualified Organization or Non-United States Person.

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

                  "Plan": Any employee benefit plan or certain other retirement
plans and arrangements, including individual retirement accounts and annuities,
Keogh plans and bank collective investment funds and insurance company general
or separate accounts in which such plans, accounts or arrangements are invested,
that are subject to ERISA and Section 4975 of the Code.

                  "PMI Insurer": Radian Guaranty Inc., a Pennsylvania
corporation, or its successors in interest.

                                      -29-

<PAGE>

                  "PMI Insurer Fee": The amount payable to the PMI Insurer on
each Distribution Date, which amount shall equal (a) one twelfth of the product
of (i) the PMI Insurer Fee Rate, multiplied by (ii) the aggregate Principal
Balance of the PMI Mortgage Loans and any related REO Properties as of the first
day of the related Due Period (after giving effect to scheduled payments of
principal due during the Due Period relating to the previous Distribution Date,
to the extent received or advanced) plus (b) any taxes on PMI Mortgage Loans
located in West Virginia and Kentucky.

                  "PMI Insurer Fee Rate": 1.14% per annum.

                  "PMI Mortgage Loans": The list of Mortgage Loans insured by
the PMI Insurer attached hereto as Schedule 3.

                  "PMI Policy": The Primary Mortgage Insurance Policy No. 61368
(policy reference number: 03-998010) with respect to the PMI Mortgage Loans,
including all endorsements thereto dated the Closing Date, issued by the PMI
Insurer and the Commitment Letter, dated February 27, 2003, between the PMI
Insurer and the Seller.

                  "Prepayment Assumption": As defined in the Prospectus
Supplement.

                  "Prepayment Charge": With respect to any Prepayment Period,
any prepayment premium, fee, penalty or charge payable by a Mortgagor in
connection with any full or partial Principal Prepayment on a Mortgage Loan
pursuant to the terms of the related Mortgage Note (other than any Master
Servicer Prepayment Charge Payment Amount).

                  "Prepayment Charge Schedule": As of any date, the list of
Prepayment Charges on the Mortgage Loans included in REMIC I on such date,
attached hereto as Schedule 2 (including the Prepayment Charge Summary attached
thereto). The Prepayment Charge Schedule shall set forth the following
information with respect to each related Mortgage Loan:

                  (i)      the Mortgage Loan identifying number;

                  (ii)     a code indicating the type of Prepayment Charge;

                  (iii)    the state of origination of the related Mortgage
         Loan;

                  (iv)     the date on which the first monthly payment was due
         on the related Mortgage Loan;

                  (v)      the term of the related Mortgage Loan; and

                  (vi)     the principal balance of the related Mortgage Loan as
         of the Cut-off Date.

                  The Prepayment Charge Schedule shall be amended from time to
time by the Depositor in accordance with the provisions of this Agreement and a
copy of such amended Prepayment Charge Schedule shall be furnished by the Master
Servicer to the NIMS Insurer.

                                      -30-

<PAGE>

                  "Prepayment Interest Excess": With respect to any Distribution
Date, for each Mortgage Loan that was the subject of a Principal Prepayment in
full during the portion of the related Prepayment Period occurring between the
first day and the Determination Date of the calendar month in which such
Distribution Date occurs, an amount equal to interest (to the extent received)
at the applicable Net Mortgage Rate on the amount of such Principal Prepayment
for the number of days commencing on the first day of the calendar month in
which such Distribution Date occurs and ending on the date on which such
prepayment is so applied.

                  "Prepayment Interest Shortfall": With respect to any
Distribution Date, for each Mortgage Loan that was the subject of a Principal
Prepayment in full during the portion of the related Prepayment Period occurring
between the first day of the related Prepayment Period and the last day of the
calendar month preceding the month in which such Distribution Date occurs, an
amount equal to interest at the applicable Net Mortgage Rate on the amount of
such Principal Prepayment for the number of days commencing on the date on which
the prepayment is applied and ending on the last day of the calendar month
preceding the month in which such Distribution Date occurs. The obligations of
the Master Servicer in respect of any Prepayment Interest Shortfall are set
forth in Section 3.24.

                  "Prepayment Period": With respect to any Distribution Date,
the period commencing on the day after the Determination Date in the calendar
month preceding the calendar month in which such Distribution Date occurs (or,
in the case of the first Distribution Date, commencing on February 1, 2003) and
ending on the Determination Date of the calendar month in which such
Distribution Date occurs.

                  "Principal Balance": As to any Mortgage Loan other than a
Liquidated Mortgage Loan, and any day, the related Cut-off Date Principal
Balance, minus all collections credited against the Cut-off Date Principal
Balance of any such Mortgage Loan. For purposes of this definition, a Liquidated
Mortgage Loan shall be deemed to have a Principal Balance equal to the Principal
Balance of the related Mortgage Loan as of the final recovery of related
Liquidation Proceeds and a Principal Balance of zero thereafter. As to any REO
Property and any day, the Principal Balance of the related Mortgage Loan
immediately prior to such Mortgage Loan becoming REO Property minus any REO
Principal Amortization received with respect thereto on or prior to such day.

                  "Principal Prepayment": Any payment of principal made by the
Mortgagor on a Mortgage Loan which is received in advance of its scheduled Due
Date and which is not accompanied by an amount of interest representing the full
amount of scheduled interest due on any Due Date in any month or months
subsequent to the month of prepayment.

                  "Principal Remittance Amount": With respect to any
Distribution Date, the sum of the Group I Principal Remittance Amount and the
Group II Principal Remittance Amount.

                  "Prospectus Supplement": That certain Prospectus Supplement
dated February 24, 2003 relating to the public offering of the Class A
Certificates and the Mezzanine Certificates.

                  "PTCE": A Prohibited Transaction Class Exemption issued by the
United States Department of Labor which provides that exemptive relief is
available to any party to any transaction

                                      -31-

<PAGE>

which satisfies the conditions of the exemption.

                  "Purchase Price": With respect to any Mortgage Loan or REO
Property to be purchased pursuant to or as contemplated by Section 2.03, Section
3.16(c) or Section 9.01, and as confirmed by an Officer's Certificate from the
Master Servicer and to the Trustee an amount equal to the sum of (i) 100% of the
Stated Principal Balance thereof as of the date of purchase (or such other price
as provided in Section 9.01), (ii) in the case of (x) a Mortgage Loan, accrued
interest on such Stated Principal Balance at the applicable Net Mortgage Rate in
effect from time to time from the Due Date as to which interest was last covered
by a payment by the Mortgagor or an advance by the Master Servicer, which
payment or advance had as of the date of purchase been distributed pursuant to
Section 4.01, through the end of the calendar month in which the purchase is to
be effected and (y) an REO Property, the sum of (1) accrued interest on such
Stated Principal Balance at the applicable Net Mortgage Rate in effect from time
to time from the Due Date as to which interest was last covered by a payment by
the Mortgagor or an advance by the Master Servicer through the end of the
calendar month immediately preceding the calendar month in which such REO
Property was acquired, plus (2) REO Imputed Interest for such REO Property for
each calendar month commencing with the calendar month in which such REO
Property was acquired and ending with the calendar month in which such purchase
is to be effected, net of the total of all net rental income, Insurance
Proceeds, Liquidation Proceeds and P& I Advances that as of the date of purchase
had been distributed as or to cover REO Imputed Interest pursuant to Section
4.01, (iii) any unreimbursed Servicing Advances and Advances (including
Nonrecoverable Advances and Nonrecoverable Servicing Advances) and any unpaid
Servicing Fees allocable to such Mortgage Loan or REO Property, (iv) any amounts
previously withdrawn from the Collection Account in respect of such Mortgage
Loan or REO Property pursuant to Section 3.11(a)(ix) and Section 3.16(b), and
(v) in the case of a Mortgage Loan required to be purchased pursuant to Section
2.03, expenses reasonably incurred or to be incurred by the Master Servicer, the
NIMS Insurer or the Trustee in respect of the breach or defect giving rise to
the purchase obligation.

                  "Qualified Substitute Mortgage Loan": A mortgage loan
substituted for a Deleted Mortgage Loan pursuant to the terms of this Agreement
which must, on the date of such substitution, (i) have an outstanding Principal
Balance, after application of all scheduled payments of principal and interest
due during or prior to the month of substitution, not in excess of the Principal
Balance of the Deleted Mortgage Loan as of the Due Date in the calendar month
during which the substitution occurs, (ii) have a Mortgage Rate not less than
(and not more than one percentage point in excess of) the Mortgage Rate of the
Deleted Mortgage Loan, (iii) with respect to any Adjustable- Rate Mortgage Loan,
have a Maximum Mortgage Rate not less than the Maximum Mortgage Rate on the
Deleted Mortgage Loan, (iv) with respect to any Adjustable-Rate Mortgage Loan,
have a Minimum Mortgage Rate not less than the Minimum Mortgage Rate of the
Deleted Mortgage Loan, (v) with respect to any Adjustable-Rate Mortgage Loan,
have a Gross Margin equal to the Gross Margin of the Deleted Mortgage Loan, (vi)
with respect to any Adjustable-Rate Mortgage Loan, have a next Adjustment Date
not more than two months later than the next Adjustment Date on the Deleted
Mortgage Loan, (vii) have a remaining term to maturity not greater than (and not
more than one year less than) that of the Deleted Mortgage Loan, (viii) have the
same Due Date as the Due Date on the Deleted Mortgage Loan, (ix) have a
Loan-to-Value Ratio as of the date of substitution equal to or lower than the
Loan-to-Value Ratio of the Deleted Mortgage Loan as of such date, (x) have a
risk grading determined by the Originator at least equal to the risk grading
assigned on the Deleted

                                      -32-

<PAGE>

Mortgage Loan, (xi) have a Prepayment Charge provision at least equal to the
Prepayment Charge provision in the Deleted Mortgage Loan, (xii) be covered by
the PMI Policy if the Deleted Mortgage Loan was covered by the PMI Policy and
(xiii) conform to each representation and warranty set forth in Section 6 of the
Mortgage Loan Purchase Agreement applicable to the Deleted Mortgage Loan. In the
event that one or more mortgage loans are substituted for one or more Deleted
Mortgage Loans, the amounts described in clause (i) hereof shall be determined
on the basis of aggregate principal balances, the Mortgage Rates described in
clause (ii) hereof shall be determined on the basis of weighted average Mortgage
Rates, the terms described in clause (vii) hereof shall be determined on the
basis of weighted average remaining term to maturity, the Loan-to-Value Ratios
described in clause (ix) hereof shall be satisfied as to each such mortgage
loan, the risk gradings described in clause (x) hereof shall be satisfied as to
each such mortgage loan and, except to the extent otherwise provided in this
sentence, the representations and warranties described in clause (xi) hereof
must be satisfied as to each Qualified Substitute Mortgage Loan or in the
aggregate, as the case may be.

                  "Rating Agency or Rating Agencies": Fitch, Moody's and S&P or
their successors. If such agencies or their successors are no longer in
existence, "Rating Agencies" shall be such nationally recognized statistical
rating agencies, or other comparable Persons, designated by the Depositor,
notice of which designation shall be given to the Trustee and the Master
Servicer.

                  "Realized Loss": With respect to each Mortgage Loan as to
which a Final Recovery Determination has been made, an amount (not less than
zero) equal to (i) the unpaid Principal Balance of such Mortgage Loan as of the
commencement of the calendar month in which the Final Recovery Determination was
made, plus (ii) accrued interest from the Due Date as to which interest was last
paid by the Mortgagor through the end of the calendar month in which such Final
Recovery Determination was made, calculated in the case of each calendar month
during such period (A) at an annual rate equal to the annual rate at which
interest was then accruing on such Mortgage Loan and (B) on a principal amount
equal to the Stated Principal Balance of such Mortgage Loan as of the close of
business on the Distribution Date during such calendar month, plus (iii) any
amounts previously withdrawn from the Collection Account in respect of such
Mortgage Loan pursuant to Section 3.11(a)(ix) and Section 3.16(b), minus (iv)
the proceeds, if any, received in respect of such Mortgage Loan during the
calendar month in which such Final Recovery Determination was made, net of
amounts that are payable therefrom to the Master Servicer with respect to such
Mortgage Loan pursuant to Section 3.11(a)(iii).

                  With respect to any REO Property as to which a Final Recovery
Determination has been made, an amount (not less than zero) equal to (i) the
unpaid principal balance of the related Mortgage Loan as of the date of
acquisition of such REO Property on behalf of REMIC I, plus (ii) accrued
interest from the Due Date as to which interest was last paid by the Mortgagor
in respect of the related Mortgage Loan through the end of the calendar month
immediately preceding the calendar month in which such REO Property was
acquired, calculated in the case of each calendar month during such period (A)
at an annual rate equal to the annual rate at which interest was then accruing
on the related Mortgage Loan and (B) on a principal amount equal to the Stated
Principal Balance of the related Mortgage Loan as of the close of business on
the Distribution Date during such calendar month, plus (iii) REO Imputed
Interest for such REO Property for each calendar month commencing with the
calendar month in which such REO Property was acquired and ending with

                                      -33-

<PAGE>

the calendar month in which such Final Recovery Determination was made, plus
(iv) any amounts previously withdrawn from the Collection Account in respect of
the related Mortgage Loan pursuant to Section 3.11(a)(ix) and Section 3.16(b),
minus (v) the aggregate of all P& I Advances and Servicing Advances (in the case
of Servicing Advances, without duplication of amounts netted out of the rental
income, Insurance Proceeds and Liquidation Proceeds described in clause (vi)
below) made by the Master Servicer in respect of such REO Property or the
related Mortgage Loan for which the Master Servicer has been or, in connection
with such Final Recovery Determination, will be reimbursed pursuant to Section
3.23 out of rental income, Insurance Proceeds and Liquidation Proceeds received
in respect of such REO Property, minus (vi) the total of all net rental income,
Insurance Proceeds and Liquidation Proceeds received in respect of such REO
Property that has been, or in connection with such Final Recovery Determination,
will be transferred to the Distribution Account pursuant to Section 3.23.

                  With respect to each Mortgage Loan which has become the
subject of a Deficient Valuation, the difference between the principal balance
of the Mortgage Loan outstanding immediately prior to such Deficient Valuation
and the principal balance of the Mortgage Loan as reduced by the Deficient
Valuation.

                  With respect to each Mortgage Loan which has become the
subject of a Debt Service Reduction, the portion, if any, of the reduction in
each affected Monthly Payment attributable to a reduction in the Mortgage Rate
imposed by a court of competent jurisdiction. Each such Realized Loss shall be
deemed to have been incurred on the Due Date for each affected Monthly Payment.

                  "Record Date": With respect to each Distribution Date and any
Book-Entry Certificate (other than the Class MF-5 Certificates), the Business
Day immediately preceding such Distribution Date. With respect to each
Distribution Date and any other Certificates, including the Class MF-5
Certificates and any Definitive Certificates, the last Business Day of the month
immediately preceding the month in which such Distribution Date occurs.

                  "Reference Banks": Bankers Trust Company, Barclay's Bank PLC,
The Tokyo Mitsubishi Bank and National Westminster Bank PLC and their successors
in interest; provided, however, that if any of the foregoing banks are not
suitable to serve as a Reference Bank, then any leading banks selected by the
Trustee (after consultation with the NIMS Insurer) which are engaged in
transactions in Eurodollar deposits in the international Eurocurrency market (i)
with an established place of business in London, (ii) not controlling, under the
control of or under common control with the Depositor or any Affiliate thereof
and (iii) which have been designated as such by the Trustee.

                  "Refinanced Mortgage Loan": A Mortgage Loan the proceeds of
which were not used to purchase the related Mortgaged Property.

                  "Regular Certificate": Any Class A Certificate, Mezzanine
Certificate, Class CE Certificate or Class P Certificate.

                  "Regular Interest": A "regular interest" in a REMIC within the
meaning of Section 860G(a)(1) of the Code.

                                      -34-

<PAGE>

                  "Relief Act": The Soldiers' and Sailors' Civil Relief Act of
1940, as amended.

                  "Relief Act Interest Shortfall": With respect to any
Distribution Date and any Mortgage Loan, any reduction in the amount of interest
collectible on such Mortgage Loan for the most recently ended calendar month as
a result of the application of the Relief Act.

                  "REMIC": A "real estate mortgage investment conduit" within
the meaning of Section 860D of the Code.

                  "REMIC I": The segregated pool of assets subject hereto,
constituting the primary trust created hereby and to be administered hereunder,
with respect to which a REMIC election is to be made, consisting of: (i) such
Mortgage Loans and Prepayment Charges as from time to time are subject to this
Agreement, together with the Mortgage Files relating thereto, and together with
all collections thereon and proceeds thereof; (ii) any REO Property, together
with all collections thereon and proceeds thereof; (iii) the Trustee's rights
with respect to the Mortgage Loans under all insurance policies, including the
PMI Policy, required to be maintained pursuant to this Agreement and any
proceeds thereof; (iv) the Depositor's rights under the Mortgage Loan Purchase
Agreement (including any security interest created thereby); (v) the Collection
Account (other than any amounts representing any Master Servicer Prepayment
Charge Payment Amount), the Distribution Account (other than any amounts
representing any Master Servicer Prepayment Charge Payment Amount) and any REO
Account, and such assets that are deposited therein from time to time and any
investments thereof, together with any and all income, proceeds and payments
with respect thereto. Notwithstanding the foregoing, however, REMIC I
specifically excludes the Net WAC Rate Carryover Reserve Account, all payments
and other collections of principal and interest due on the Mortgage Loans on or
before the Cut-off Date and all Prepayment Charges payable in connection with
Principal Prepayments made before the Cut-off Date.

                  "REMIC I Interest Loss Allocation Amount": With respect to any
Distribution Date, an amount (subject to adjustment based on the actual number
of days elapsed in the respective Accrual Periods for the indicated Regular
Interests for such Distribution Date) equal to (a) the product of (i) 50% of the
aggregate Stated Principal Balance of the Mortgage Loans and REO Properties then
outstanding and (ii) the REMIC I Remittance Rate for REMIC I Regular Interest I-
LTAA minus the Marker Rate, divided by (b) 12.

                  "REMIC I Marker Allocation Percentage": 50% of any amount
payable or loss attributable from the Mortgage Loans, which shall be allocated
to REMIC I Regular Interest I-LTAA, REMIC I Regular Interest I-LTA1, REMIC I
Regular Interest I-LTA2, REMIC I Regular Interest I- LTM1, REMIC I Regular
Interest I-LTM2, REMIC I Regular Interest I-LTM3, REMIC I Regular Interest
I-LTM4, REMIC I Regular Interest I-LTMV5, REMIC I Regular Interest I-LTMF5,
REMIC I Regular Interest I-LTZZ and REMIC I Regular Interest I-LTP.

                  "REMIC I Overcollateralized Amount": With respect to any date
of determination, (i) 1% of the aggregate Uncertificated Balances of the REMIC I
Regular Interests minus (ii) the aggregate of the Uncertificated Balances of
REMIC I Regular Interest I-LTA1, REMIC I Regular Interest I-LTA2, REMIC I
Regular Interest I-LTM1, REMIC I Regular Interest I-LTM2, REMIC I Regular
Interest I-LTM3, REMIC I Regular Interest I-LTM4, REMIC I Regular Interest
I-LTMV5

                                      -35-

<PAGE>

and REMIC I Regular Interest I-LTMF5, in each case as of such date of
determination.

                  "REMIC I Principal Loss Allocation Amount": With respect to
any Distribution Date, an amount equal to the product of (i) the aggregate
Stated Principal Balance of the Mortgage Loans and REO Properties then
outstanding and (ii) 1 minus a fraction, the numerator of which is two times the
aggregate of the Uncertificated Balances of REMIC I Regular Interest I-LTA1,
REMIC I Regular Interest I-LTA2, REMIC I Regular Interest I-LTM1, REMIC I
Regular Interest I-LTM2, REMIC I Regular Interest I-LTM3, REMIC I Regular
Interest I-LTM4, REMIC I Regular Interest I-LTMV5 and REMIC I Regular Interest
I-LTMF5 and the denominator of which is the aggregate of the Uncertificated
Balances of REMIC I Regular Interest I-LTA1, REMIC I Regular Interest I-LTA2,
REMIC I Regular Interest I-LTM1, REMIC I Regular Interest I-LTM2, REMIC I
Regular Interest I-LTM3, REMIC I Regular Interest I-LTM4, REMIC I Regular
Interest I-LTMV5, REMIC I Regular Interest I-LTMF5 and REMIC I Regular Interest
I-LTZZ.

                  "REMIC I Regular Interest": Any of the separate
non-certificated beneficial ownership interests in REMIC I issued hereunder and
designated as a "regular interest" in REMIC I. Each REMIC I Regular Interest
shall accrue interest at the related REMIC I Remittance Rate in effect from time
to time, and shall be entitled to distributions of principal, subject to the
terms and conditions hereof, in an aggregate amount equal to its initial
Uncertificated Balance as set forth in the Preliminary Statement hereto. The
designations for the respective REMIC I Regular Interests are set forth in the
Preliminary Statement hereto.

                  "REMIC I Regular Interest I-LTAA": One of the separate
non-certificated beneficial ownership interests in REMIC I issued hereunder and
designated as a Regular Interest in REMIC I. REMIC I Regular Interest I-LTAA
shall accrue interest at the related REMIC I Remittance Rate in effect from time
to time, and shall be entitled to distributions of principal, subject to the
terms and conditions hereof, in an aggregate amount equal to its initial
Uncertificated Balance as set forth in the Preliminary Statement hereto.

                  "REMIC I Regular Interest I-LTA1": One of the separate
non-certificated beneficial ownership interests in REMIC I issued hereunder and
designated as a Regular Interest in REMIC I. REMIC I Regular Interest I-LTA1
shall accrue interest at the related REMIC I Remittance Rate in effect from time
to time, and shall be entitled to distributions of principal, subject to the
terms and conditions hereof, in an aggregate amount equal to its initial
Uncertificated Balance as set forth in the Preliminary Statement hereto.

                  "REMIC I Regular Interest I-LTA2": One of the separate
non-certificated beneficial ownership interests in REMIC I issued hereunder and
designated as a Regular Interest in REMIC I. REMIC I Regular Interest I-LTA2
shall accrue interest at the related REMIC I Remittance Rate in effect from time
to time, and shall be entitled to distributions of principal, subject to the
terms and conditions hereof, in an aggregate amount equal to its initial
Uncertificated Balance as set forth in the Preliminary Statement hereto.

                  "REMIC I Regular Interest I-LTM1": One of the separate
non-certificated beneficial ownership interests in REMIC I issued hereunder and
designated as a Regular Interest in REMIC I. REMIC I Regular Interest I-LTM1
shall accrue interest at the related REMIC I Remittance Rate in

                                      -36-

<PAGE>

effect from time to time, and shall be entitled to distributions of principal,
subject to the terms and conditions hereof, in an aggregate amount equal to its
initial Uncertificated Balance as set forth in the Preliminary Statement hereto.

                  "REMIC I Regular Interest I-LTM2": One of the separate
non-certificated beneficial ownership interests in REMIC I issued hereunder and
designated as a Regular Interest in REMIC I. REMIC I Regular Interest I-LTM2
shall accrue interest at the related REMIC I Remittance Rate in effect from time
to time, and shall be entitled to distributions of principal, subject to the
terms and conditions hereof, in an aggregate amount equal to its initial
Uncertificated Balance as set forth in the Preliminary Statement hereto.

                  "REMIC I Regular Interest I-LTM3": One of the separate
non-certificated beneficial ownership interests in REMIC I issued hereunder and
designated as a Regular Interest in REMIC I. REMIC I Regular Interest I-LTM3
shall accrue interest at the related REMIC I Remittance Rate in effect from time
to time, and shall be entitled to distributions of principal, subject to the
terms and conditions hereof, in an aggregate amount equal to its initial
Uncertificated Balance as set forth in the Preliminary Statement hereto.

                  "REMIC I Regular Interest I-LTM4": One of the separate
non-certificated beneficial ownership interests in REMIC I issued hereunder and
designated as a Regular Interest in REMIC I. REMIC I Regular Interest I-LTM4
shall accrue interest at the related REMIC I Remittance Rate in effect from time
to time, and shall be entitled to distributions of principal, subject to the
terms and conditions hereof, in an aggregate amount equal to its initial
Uncertificated Balance as set forth in the Preliminary Statement hereto.

                  "REMIC I Regular Interest I-LTMV5": One of the separate
non-certificated beneficial ownership interests in REMIC I issued hereunder and
designated as a Regular Interest in REMIC I. REMIC I Regular Interest I-LTMV5
shall accrue interest at the related REMIC I Remittance Rate in effect from time
to time, and shall be entitled to distributions of principal, subject to the
terms and conditions hereof, in an aggregate amount equal to its initial
Uncertificated Balance as set forth in the Preliminary Statement hereto.

                  "REMIC I Regular Interest I-LTMF5": One of the separate
non-certificated beneficial ownership interests in REMIC I issued hereunder and
designated as a Regular Interest in REMIC I. REMIC I Regular Interest I-LTMF5
shall accrue interest at the related REMIC I Remittance Rate in effect from time
to time, and shall be entitled to distributions of principal, subject to the
terms and conditions hereof, in an aggregate amount equal to its initial
Uncertificated Balance as set forth in the Preliminary Statement hereto.

                  "REMIC I Regular Interest I-LTP": One of the separate
non-certificated beneficial ownership interests in REMIC I issued hereunder and
designated as a Regular Interest in REMIC I. REMIC I Regular Interest I-LTP
shall be entitled to any Prepayment Charges collected by the Master Servicer and
to a distribution of principal, subject to the terms and conditions hereof, in
an aggregate amount equal to its initial Uncertificated Balance as set forth in
the Preliminary Statement hereto.

                  "REMIC I Regular Interest I-LTZZ": One of the separate
non-certificated beneficial

                                      -37-

<PAGE>

ownership interests in REMIC I issued hereunder and designated as a Regular
Interest in REMIC I. REMIC I Regular Interest I-LTZZ shall accrue interest at
the related REMIC I Remittance Rate in effect from time to time, and shall be
entitled to distributions of principal, subject to the terms and conditions
hereof, in an aggregate amount equal to its initial Uncertificated Balance as
set forth in the Preliminary Statement hereto.

                  "REMIC I Regular Interest I-LT1SUB": One of the separate
non-certificated beneficial ownership interests in REMIC I issued hereunder and
designated as a Regular Interest in REMIC I. REMIC I Regular Interest I-LT1SUB
shall accrue interest at the related REMIC I Remittance Rate in effect from time
to time, and shall be entitled to distributions of principal, subject to the
terms and conditions hereof, in an aggregate amount equal to its initial
Uncertificated Balance as set forth in the Preliminary Statement hereto.

                  "REMIC I Regular Interest I-LT1GRP": One of the separate
non-certificated beneficial ownership interests in REMIC I issued hereunder and
designated as a Regular Interest in REMIC I. REMIC I Regular Interest I-LT1GRP
shall accrue interest at the related REMIC I Remittance Rate in effect from time
to time, and shall be entitled to distributions of principal, subject to the
terms and conditions hereof, in an aggregate amount equal to its initial
Uncertificated Balance as set forth in the Preliminary Statement hereto.

                  "REMIC I Regular Interest I-LT2SUB": One of the separate
non-certificated beneficial ownership interests in REMIC I issued hereunder and
designated as a Regular Interest in REMIC I. REMIC I Regular Interest I-LT2SUB
shall accrue interest at the related REMIC I Remittance Rate in effect from time
to time, and shall be entitled to distributions of principal, subject to the
terms and conditions hereof, in an aggregate amount equal to its initial
Uncertificated Balance as set forth in the Preliminary Statement hereto.

                  "REMIC I Regular Interest I-LT2GRP": One of the separate
non-certificated beneficial ownership interests in REMIC I issued hereunder and
designated as a Regular Interest in REMIC I. REMIC I Regular Interest I-LT2GRP
shall accrue interest at the related REMIC I Remittance Rate in effect from time
to time, and shall be entitled to distributions of principal, subject to the
terms and conditions hereof, in an aggregate amount equal to its initial
Uncertificated Balance as set forth in the Preliminary Statement hereto.

                  "REMIC I Regular Interest I-LTXX": One of the separate
non-certificated beneficial ownership interests in REMIC I issued hereunder and
designated as a Regular Interest in REMIC I. REMIC I Regular Interest I-LTXX
shall accrue interest at the related REMIC I Remittance Rate in effect from time
to time, and shall be entitled to distributions of principal, subject to the
terms and conditions hereof, in an aggregate amount equal to its initial
Uncertificated Balance as set forth in the Preliminary Statement hereto.

                  "REMIC I Remittance Rate": With respect to REMIC I Regular
Interest I-LTAA, REMIC I Regular Interest I-LTA1, REMIC I Regular Interest
I-LTA2, REMIC I Regular Interest I- LTM1, REMIC I Regular Interest I-LTM2, REMIC
I Regular Interest I-LTM3, REMIC I Regular Interest I-LTM4, REMIC I Regular
Interest I-LTMV5, REMIC I Regular Interest I-LTMF5, REMIC I Regular Interest
I-LTZZ, REMIC I Regular Interest I-LTP, REMIC I Regular Interest I-LT1SUB,

                                      -38-

<PAGE>

REMIC I Regular Interest I-LT2SUB and REMIC I Regular Interest I-LTXX, the
weighted average of the Adjusted Net Mortgage Rates of the Mortgage Loans. With
respect to REMIC I Regular Interest I-LT1GRP, the weighted average of the
Adjusted Net Mortgage Rates of the Group I Mortgage Loans and with respect REMIC
I Regular Interest I-LT2GRP, the weighted average of the Adjusted Net Mortgage
Rates of the Group II Mortgage Loans.

                  "REMIC I Subordinated Balance Ratio": The ratio among the
Uncertificated Balances of each REMIC I Regular Interest ending with the
designation "SUB,", equal to the ratio among, with respect to each such REMIC I
Regular Interest, the excess of (x) the aggregate Stated Principal Balance of
the Mortgage Loans in the related Loan Group over (y) the Current Principal
Amount of the Class A Certificates in the related Loan Group.

                  "REMIC I Sub WAC Allocation Percentage": 50% of any amount
payable or loss attributable from the Mortgage Loans, which shall be allocated
to REMIC I Regular Interest I- LT1SUB, REMIC I Regular Interest I-LT1GRP, REMIC
I Regular Interest I-LT2SUB, REMIC I Regular Interest I-LT2GRP and REMIC I
Regular Interest I-LTXX.

                  "REMIC I Required Overcollateralized Amount": 0.50% of the
Overcollateralization Target Amount.

                  "REMIC II": The segregated pool of assets consisting of all of
the REMIC I Regular Interests conveyed in trust to the Trustee, for the benefit
of the REMIC II Certificateholders pursuant to Section 2.07, and all amounts
deposited therein, with respect to which a separate REMIC election is to be
made.

                  "REMIC II Certificate": Any Regular Certificate or Class R
Certificate.

                  "REMIC II Certificateholder": The Holder of any REMIC III
Certificate.

                  "REMIC Provisions": Provisions of the federal income tax law
relating to real estate mortgage investment conduits, which appear at Section
860A through 860G of the Code, and related provisions, and proposed, temporary
and final regulations and published rulings, notices and announcements
promulgated thereunder, as the foregoing may be in effect from time to time.

                  "Remittance Report": A report prepared by the Master Servicer
and delivered to the Trustee and the NIMS Insurer pursuant to Section 4.03.

                  "Rents from Real Property": With respect to any REO Property,
gross income of the character described in Section 856(d) of the Code as being
included in the term "rents from real property."

                  "REO Account": The account or accounts maintained, or caused
to be maintained, by the Master Servicer in respect of an REO Property pursuant
to Section 3.23.

                  "REO Disposition": The sale or other disposition of an REO
Property on behalf of REMIC I.

                                      -39-

<PAGE>

                  "REO Imputed Interest": As to any REO Property, for any
calendar month during which such REO Property was at any time part of REMIC I,
one month's interest at the applicable Net Mortgage Rate on the Stated Principal
Balance of such REO Property (or, in the case of the first such calendar month,
of the related Mortgage Loan, if appropriate) as of the close of business on the
Distribution Date in such calendar month.

                  "REO Principal Amortization": With respect to any REO
Property, for any calendar month, the excess, if any, of (a) the aggregate of
all amounts received in respect of such REO Property during such calendar month,
whether in the form of rental income, sale proceeds (including, without
limitation, that portion of the Termination Price paid in connection with a
purchase of all of the Mortgage Loans and REO Properties pursuant to Section
9.01 that is allocable to such REO Property) or otherwise, net of any portion of
such amounts (i) payable pursuant to Section 3.23(c) in respect of the proper
operation, management and maintenance of such REO Property or (ii) payable or
reimbursable to the Master Servicer pursuant to Section 3.23(d) for unpaid
Servicing Fees in respect of the related Mortgage Loan and unreimbursed
Servicing Advances and Advances in respect of such REO Property or the related
Mortgage Loan, over (b) the REO Imputed Interest in respect of such REO Property
for such calendar month.

                  "REO Property": A Mortgaged Property acquired by the Master
Servicer on behalf of REMIC I through foreclosure or deed-in-lieu of
foreclosure, as described in Section 3.23.

                  "Request for Release": A release signed by a Servicing
Officer, in the form of Exhibit E attached hereto.

                  "Reserve Interest Rate": With respect to any Interest
Determination Date, the rate per annum that the Trustee determines to be either
(i) the arithmetic mean (rounded upwards if necessary to the nearest whole
multiple of 1/16%) of the one-month U.S. dollar lending rates which New York
City banks selected by the Trustee are quoting on the relevant Interest
Determination Date to the principal London offices of leading banks in the
London interbank market or (ii) in the event that the Trustee can determine no
such arithmetic mean, the lowest one-month U.S. dollar lending rate which New
York City banks selected by the Trustee are quoting on such Interest
Determination Date to leading European banks.

                  "Residential Dwelling": Any one of the following: (i) a
detached one-family dwelling, (ii) a detached two- to four-family dwelling,
(iii) a one-family dwelling unit in a Fannie Mae eligible condominium project,
(iv) a manufactured home, or (v) a detached one-family dwelling in a planned
unit development, none of which is a co-operative or mobile home.

                  "Residual Certificate": Any one of the Class R Certificates.

                  "Residual Interest": The sole class of "residual interests" in
a REMIC within the meaning of Section 860G(a)(2) of the Code.

                  "Responsible Officer": When used with respect to the Trustee,
the Chairman or Vice Chairman of the Board of Directors or Trustees, the
Chairman or Vice Chairman of the Executive or Standing Committee of the Board of
Directors or Trustees, the President, the Chairman of the

                                      -40-

<PAGE>

Committee on Trust Matters, any vice president, any assistant vice president,
the Secretary, any assistant secretary, the Treasurer, any assistant treasurer,
the Cashier, any assistant cashier, any trust officer or assistant trust
officer, the Controller and any assistant controller or any other officer of the
Trustee, customarily performing functions similar to those performed by any of
the above designated officers and, with respect to a particular matter, to whom
such matter is referred because of such officer's knowledge of and familiarity
with the particular subject.

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

                  "Seller": UBS Warburg Real Estate Securities Inc. or its
successor in interest, in its capacity as seller under the Mortgage Loan
Purchase Agreement.

                  "Servicing Account": The account or accounts created and
maintained pursuant to Section 3.09.

                  "Servicing Advances": All customary, reasonable and necessary
"out of pocket" costs and expenses (including reasonable attorneys' fees and
expenses) incurred by the Master Servicer in the performance of its servicing
obligations, including, but not limited to, the cost of (i) the preservation,
restoration, inspection and protection of the Mortgaged Property, (ii) any
enforcement or judicial proceedings, including foreclosures, (iii) the
management and liquidation of the REO Property and (iv) compliance with the
obligations under Sections 3.01, 3.09, 3.16, and 3.23.

                  "Servicing Fee": With respect to each Mortgage Loan and for
any calendar month, an amount equal to one month's interest (or in the event of
any payment of interest which accompanies a Principal Prepayment in full or in
part made by the Mortgagor during such calendar month, interest for the number
of days covered by such payment of interest) at the Servicing Fee Rate on the
same principal amount on which interest on such Mortgage Loan accrues for such
calendar month. A portion of such Servicing Fee may be retained by any
Sub-Servicer as its servicing compensation.

                  "Servicing Fee Rate": 0.50% per annum.

                  "Servicing Officer": Any officer of the Master Servicer
involved in, or responsible for, the administration and servicing of Mortgage
Loans, whose name and specimen signature appear on a list of Servicing Officers
furnished by the Master Servicer to the Trustee and the Depositor on the Closing
Date, as such list may from time to time be amended.

                  "Servicing Standard": Shall mean the standards set forth in
Section 3.01.

                  "Servicing Transfer Costs": Shall mean all reasonable costs
and expenses incurred by the Trustee in connection with the transfer of
servicing from a predecessor servicer, including, without limitation, any
reasonable costs or expenses associated with the complete transfer of all
servicing data and the completion, correction or manipulation of such servicing
data as may be required by the Trustee to correct any errors or insufficiencies
in the servicing data or otherwise to enable the Trustee to service the Mortgage
Loans properly and effectively.

                                      -41-

<PAGE>

                  "Single Certificate": With respect to any Class of
Certificates (other than the Class P Certificates and the Residual
Certificates), a hypothetical Certificate of such Class evidencing a Percentage
Interest for such Class corresponding to an initial Certificate Principal
Balance (or Notional Amount in the case of the Class S Certificates) of $1,000.
With respect to the Class P Certificates and the Residual Certificates, a
hypothetical Certificate of such Class evidencing a 100% Percentage Interest in
such Class.

                  "Startup Day": With respect to each Trust REMIC, the day
designated as such pursuant to Section 10.01(b) hereof.

                  "Stated Principal Balance": With respect to any Mortgage Loan:
(a) as of any date of determination up to but not including the Distribution
Date on which the proceeds, if any, of a Liquidation Event with respect to such
Mortgage Loan would be distributed, the Cut-off Date Principal Balance of such
Mortgage Loan, as shown in the Mortgage Loan Schedule, minus the sum of (i) the
principal portion of each Monthly Payment due on a Due Date subsequent to the
Cut-off Date, to the extent received from the Mortgagor or advanced by the
Master Servicer and distributed pursuant to Section 4.01 on or before such date
of determination, (ii) all Principal Prepayments received after the Cut-off
Date, to the extent distributed pursuant to Section 4.01 on or before such date
of determination, (iii) all Liquidation Proceeds and Insurance Proceeds applied
by the Master Servicer as recoveries of principal in accordance with the
provisions of Section 3.16, to the extent distributed pursuant to Section 4.01
on or before such date of determination, and (iv) any Realized Loss incurred
with respect thereto as a result of a Deficient Valuation made during or prior
to the Prepayment Period for the most recent Distribution Date coinciding with
or preceding such date of determination; and (b) as of any date of determination
coinciding with or subsequent to the Distribution Date on which the proceeds, if
any, of a Liquidation Event with respect to such Mortgage Loan would be
distributed, zero. With respect to any REO Property: (a) as of any date of
determination up to but not including the Distribution Date on which the
proceeds, if any, of a Liquidation Event with respect to such REO Property would
be distributed, an amount (not less than zero) equal to the Stated Principal
Balance of the related Mortgage Loan as of the date on which such REO Property
was acquired on behalf of REMIC I, minus the sum of (i) if such REO Property was
acquired before the Distribution Date in any calendar month, the principal
portion of the Monthly Payment due on the Due Date in the calendar month of
acquisition, to the extent advanced by the Master Servicer and distributed
pursuant to Section 4.01 on or before such date of determination, and (ii) the
aggregate amount of REO Principal Amortization in respect of such REO Property
for all previously ended calendar months, to the extent distributed pursuant to
Section 4.01 on or before such date of determination; and (b) as of any date of
determination coinciding with or subsequent to the Distribution Date on which
the proceeds, if any, of a Liquidation Event with respect to such REO Property
would be distributed, zero.

                  "Stepdown Date": The earlier to occur of (i) the Distribution
Date on which the aggregate Certificate Principal Balance of the Class A
Certificates has been reduced to zero and (ii) the later to occur of (x) the
Distribution Date occurring in March 2006 and (y) the first Distribution Date on
which the Credit Enhancement Percentage (calculated for this purpose only after
taking into account payments of principal on the Mortgage Loans but prior to
distribution of the Group I Principal Distribution Amount and the Group II
Principal Distribution Amount to the Certificates then entitled to distributions
of principal on such Distribution Date) is equal to or greater than

                                      -42-

<PAGE>

24.00%.

                  "Sub-Servicer": Any Person with which the Master Servicer has
entered into a Sub- Servicing Agreement and which meets the qualifications of a
Sub-Servicer pursuant to Section 3.02.

                  "Sub-Servicing Account": An account established by a
Sub-Servicer which meets the requirements set forth in Section 3.08 and is
otherwise acceptable to the Master Servicer.

                  "Sub-Servicing Agreement": The written contract between the
Master Servicer and a Sub-Servicer relating to servicing and administration of
certain Mortgage Loans as provided in Section 3.02.

                  "Substitution Adjustment Amount": As defined in Section
2.03(b).

                  "Tax Returns": The federal income tax return on Internal
Revenue Service Form 1066, U.S. Real Estate Mortgage Investment Conduit Income
Tax Return, including Schedule Q thereto, Quarterly Notice to Residual Interest
Holders of REMIC Taxable Income or Net Loss Allocation, or any successor forms,
to be filed on behalf of the Trust Fund due to the classification of portions
thereof as REMICs under the REMIC Provisions, together with any and all other
information reports or returns that may be required to be furnished to the
Certificateholders or filed with the Internal Revenue Service or any other
governmental taxing authority under any applicable provisions of federal, state
or local tax laws.

                  "Telerate Page 3750": The display designated as page "3750" on
the Dow Jones Telerate Capital Markets Report (or such other page as may replace
page 3750 on that report for the purpose of displaying London interbank offered
rates of major banks).

                  "Termination Price": As defined in Section 9.01.

                  "Terminator": As defined in Section 9.01.

                  "Three Month Rolling Delinquency Percentage": With respect to
the Mortgage Loans and any Distribution Date, the average for the three most
recent calendar months of the fraction, expressed as a percentage, the numerator
of which is (x) the sum (without duplication) of the aggregate of the Principal
Balances of all Mortgage Loans that are (i) 60 or more days Delinquent, (ii) in
bankruptcy and 60 or more days Delinquent, (iii) in foreclosure and 60 or more
days Delinquent or (iv) REO Properties, and the denominator of which is (y) the
sum of the Principal Balances of the Mortgage Loans, in the case of both (x) and
(y), as of the Close of Business on the last Business Day of each of the three
most recent calendar months.

                  "Transfer": Any direct or indirect transfer, sale, pledge,
hypothecation, or other form of assignment of any Ownership Interest in a
Certificate.

                  "Transferee": Any Person who is acquiring by Transfer any
Ownership Interest in a Certificate.

                                      -43-

<PAGE>

                  "Transferor": Any Person who is disposing by Transfer of any
Ownership Interest in a Certificate.

                  "Trigger Event": A Trigger Event is in effect with respect to
any Distribution Date on or after the Stepdown Date if:

                  (a) the Delinquency Percentage exceeds 16.00%; or

                  (b) the aggregate amount of Realized Losses incurred since the
Cut-off Date through the last day of the related Due Period divided by the
aggregate principal balance of the Mortgage Loans as of the Cut-off Date exceeds
the applicable percentages set forth below with respect to such Distribution
Date:

      DISTRIBUTION DATE OCCURRING IN              PERCENTAGE
      ------------------------------              ----------

March 2006 through February 2007                     2.00%
March 2007 through February 2008                     3.00%
March 2008 through February 2009                     3.75%
March 2009 through February 2010                     4.00%
March 2010 and thereafter                            4.25%

                  "Trust Fund": Collectively, all of the assets of REMIC I,
REMIC II, the Net WAC Rate Carryover Reserve Account and the other assets
conveyed by the Depositor to the Trustee pursuant to Section 2.01.

                  "Trust REMIC": Either REMIC I or REMIC II.

                  "Trustee": Wells Fargo Bank Minnesota, National Association, a
national banking association, or its successor in interest, or any successor
trustee appointed as herein provided.

                  "Trustee Fee": The amount payable to the Trustee on each
Distribution Date pursuant to Section 8.05 as compensation for all services
rendered by it in the execution of the trust hereby created and in the exercise
and performance of any of the powers and duties of the Trustee hereunder, which
amount shall equal the Trustee Fee Rate accrued for one month on the aggregate
Principal Balance of the Mortgage Loans and any REO Properties as of the second
preceding Due Date (or, in the case of the initial Distribution Date, as of the
Cut-off Date), calculated on the basis of a 360-day year consisting of twelve
30-day months.

                  "Trustee Fee Rate": 0.003% per annum.

                  "Uncertificated Balance": The amount of any REMIC I Regular
Interest outstanding as of any date of determination. As of the Closing Date,
the Uncertificated Balance of each REMIC I Regular Interest shall equal the
amount set forth in the Preliminary Statement hereto as its initial
uncertificated balance. On each Distribution Date, the Uncertificated Balance of
each REMIC I Regular Interest shall be reduced by all distributions of principal
made on such REMIC I Regular

                                      -44-

<PAGE>

Interest on such Distribution Date pursuant to Section 4.01 and, if and to the
extent necessary and appropriate, shall be further reduced on such Distribution
Date by Realized Losses as provided in Section 4.04. The Uncertificated Balance
of REMIC I Regular Interest I-LTZZ shall be increased by interest deferrals as
provided in Section 4.01(a)(1)(i). The Uncertificated Balance of each REMIC I
Regular Interest shall never be less than zero.

                  "Uncertificated Interest": With respect to any REMIC I Regular
Interest for any Distribution Date, one month's interest at the REMIC I
Remittance Rate applicable to such REMIC I Regular Interest for such
Distribution Date, accrued on the Uncertificated Balance thereof immediately
prior to such Distribution Date. Uncertificated Interest in respect of any REMIC
I Regular Interest shall accrue on the basis of a 360-day year consisting of
twelve 30-day months. Uncertificated Interest with respect to each Distribution
Date, as to any REMIC I Regular Interest, shall be reduced by an amount equal to
the sum of (a) the aggregate Prepayment Interest Shortfall, if any, for such
Distribution Date to the extent not covered by payments pursuant to Section 3.24
and (b) the aggregate amount of any Relief Act Interest Shortfall, if any
allocated, in each case, to such REMIC I Regular Interest pursuant to Section
1.02. In addition, Uncertificated Interest with respect to each Distribution
Date, as to any REMIC I Regular Interest shall be reduced by Realized Losses, if
any, allocated to such REMIC I Regular Interest pursuant to Section 1.02 and
Section 4.04.

                  "Underwriters' Exemption": As defined in the Prospectus
Supplement.

                  "Uninsured Cause": Any cause of damage to a Mortgaged Property
such that the complete restoration of such property is not fully reimbursable by
the hazard insurance policies required to be maintained pursuant to Section
3.14.

                  "United States Person": A citizen or resident of the United
States, a corporation, partnership or other entity created or organized in, or
under the laws of, the United States, any state thereof or, District of Columbia
(except, in the case of a partnership, to the extent provided in regulations)
provided that, for purposes solely of the restrictions on the transfer of Class
R Certificates, no partnership or other entity treated as a partnership for
United States federal income tax purposes shall be treated as a United States
Person unless all persons that own an interest in such partnership either
directly or through any entity that is not a corporation for United States
federal income tax purposes are required by the applicable operative agreement
to be United States Persons or 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 the trust and one or more United States persons have the
authority to control all substantial decisions of the trust. To the extent
prescribed in regulations by the Secretary of the Treasury, which have not yet
been issued, a trust which was in existence on August 20, 1996 (other than a
trust treated as owned by the grantor under subpart E of part I of subchapter J
of chapter 1 of the Code), and which was treated as a United States person on
August 20, 1996 may elect to continue to be treated as a United States person
notwithstanding the previous sentence. The term "United States" shall have the
meaning set forth in Section 7701 of the Code.

                  "Unpaid Interest Shortfall Amount": With respect to the Class
A Certificates and the Mezzanine Certificates and (i) the first Distribution
Date, zero, and (ii) any Distribution Date after the first Distribution Date,
the amount, if any, by which (a) the sum of (1) the Monthly Interest

                                      -45-

<PAGE>

Distributable Amount for such Class for the immediately preceding Distribution
Date and (2) the outstanding Unpaid Interest Shortfall Amount, if any, for such
Class for such preceding Distribution Date exceeds (b) the aggregate amount
distributed on such Class in respect of interest pursuant to clause (a) of this
definition on such preceding Distribution Date, plus interest on the amount of
interest due but not paid on the Certificates of such Class on such preceding
Distribution Date, to the extent permitted by law, at the Pass-Through Rate for
such Class for the related Accrual Period.

                  "Value": With respect to any Mortgage Loan, and the related
Mortgaged Property, the lesser of:

         (i)      the lesser of (a) the value thereof as determined by an
                  appraisal made for the originator of the Mortgage Loan at the
                  time of origination of the Mortgage Loan by an appraiser who
                  met the minimum requirements of Fannie Mae and Freddie Mac,
                  and (b) the value thereof as determined by a review appraisal
                  conducted by the Originator in the event any such review
                  appraisal determines an appraised value more than 10% lower
                  than the value thereof, in the case of a Mortgaged Loan with a
                  Loan- to-Value Ratio less than or equal to 80%, or more than
                  5% lower than the value thereof, in the case of a Mortgage
                  Loan with a Loan-to-Value Ratio greater than 80%, as
                  determined by the appraisal referred to in clause (i)(a)
                  above; and

         (ii)     the purchase price paid for the related Mortgaged Property by
                  the Mortgagor with the proceeds of the Mortgage Loan;
                  provided, however, that in the case of a refinanced Mortgage
                  Loan (which is a Mortgage Loan the proceeds of which were not
                  used to purchase the related Mortgaged Property) or a Mortgage
                  Loan originated in connection with a "lease option purchase"
                  if the "lease option purchase price" was set 12 months or more
                  prior to origination, such value of the Mortgaged Property is
                  based solely upon clause (i) above..

                  "Voting Rights": The portion of the voting rights of all of
the Certificates which is allocated to any Certificate. With respect to any date
of determination, 98% of all Voting Rights will be allocated among the holders
of the Class A Certificates, the Mezzanine Certificates and the Class CE
Certificates in proportion to the then outstanding Certificate Principal
Balances of their respective Certificates, 1% of all Voting Rights will be
allocated to the holders of the Class P Certificates and 1% of all Voting Rights
will be allocated among the holders of the Residual Certificates. The Voting
Rights allocated to each Class of Certificate shall be allocated among Holders
of each such Class in accordance with their respective Percentage Interests as
of the most recent Record Date.

                  SECTION 1.02.             Allocation of Certain Interest
                                            Shortfalls.

                  For purposes of calculating the amount of the Monthly Interest
Distributable Amount for the Class A Certificates, the Mezzanine Certificates
and the Class CE Certificates for any Distribution Date, (1) the aggregate
amount of any Prepayment Interest Shortfalls (to the extent not covered by
payments by the Master Servicer pursuant to Section 3.24) and any Relief Act
Interest Shortfall incurred in respect of the Mortgage Loans for any
Distribution Date shall be allocated first, to the Class CE Certificates based
on, and to the extent of, one month's interest at the then applicable

                                      -46-

<PAGE>

respective Pass-Through Rate on the respective Notional Amount of each such
Certificate and, thereafter, among the Class A Certificates and the Mezzanine
Certificates on a PRO RATA basis based on, and to the extent of, one month's
interest at the then applicable respective Pass-Through Rate on the respective
Certificate Principal Balance of each such Certificate and (2) the aggregate
amount of any Realized Losses and Net WAC Rate Carryover Amounts incurred for
any Distribution Date shall be allocated to the Class CE Certificates based on,
and to the extent of, one month's interest at the then applicable respective
Pass-Through Rate on the respective Notional Amount of each such Certificate.

                  For purposes of calculating the amount of Uncertificated
Interest for the REMIC I Regular Interests for any Distribution Date:

         (A)      The REMIC I Marker Allocation Percentage of the aggregate
                  amount of any Prepayment Interest Shortfalls (to the extent
                  not covered by payments by the Master Servicer pursuant to
                  Section 3.24) and the REMIC I Marker Allocation Percentage of
                  the aggregate amount of any Relief Act Interest Shortfalls
                  incurred in respect of the Mortgage Loans for any Distribution
                  Date shall be allocated first, to Uncertificated Interest
                  payable to REMIC I Regular Interest I-LTAA and REMIC I Regular
                  Interest I-LTZZ up to an aggregate amount equal to the REMIC I
                  Interest Loss Allocation Amount, 98% and 2%, respectively, and
                  thereafter among REMIC I Regular Interest I-LTA1, REMIC I
                  Regular Interest I-LTA2, REMIC I Regular Interest I-LTM1,
                  REMIC I Regular Interest I-LTM2, REMIC I Regular Interest I-
                  LTM3, REMIC I Regular Interest I-LTM4, REMIC I Regular
                  Interest I-LTMV5, REMIC I Regular Interest I-LTMF5 and REMIC I
                  Regular Interest I-LTZZ PRO RATA based on, and to the extent
                  of, one month's interest at the then applicable respective
                  Pass-Through Rate on the respective Uncertificated Balance of
                  each such REMIC I Regular Interest; and

         (B)      The REMIC I Sub WAC Allocation Percentage of the aggregate
                  amount of any Prepayment Interest Shortfalls (to the extent
                  not covered by payments by the Master Servicer pursuant to
                  Section 3.24) and the REMIC I Sub WAC Allocation Percentage of
                  the aggregate amount of any Relief Act Interest Shortfalls
                  incurred in respect of the Mortgage Loans for any Distribution
                  Date shall be allocated first, to Uncertificated Interest
                  payable to REMIC I Regular Interest I-LT1SUB, REMIC I Regular
                  Interest I-LT1GRP, REMIC I Regular Interest I-LT2SUB, REMIC I
                  Regular Interest I-LT2GRP and REMIC I Regular Interest I-LTXX,
                  pro rata based on, and to the extent of, one month's interest
                  at the then applicable respective Pass-Through Rate on the
                  respective Uncertificated Balance of each such REMIC I Regular
                  Interest.

                  SECTION 1.03              Rights of the NIMS Insurer.

                  Each of the rights of the NIMS Insurer set forth in this
Agreement shall exist so long as (i) the NIMS Insurer has undertaken to
guarantee certain payments of notes issued pursuant to the Indenture and (ii)
the notes issued pursuant to the Indenture remain outstanding or the NIMS
Insurer is owed amounts in respect of its guarantee of payment on such notes;
provided, however, the NIMS

                                      -47-

<PAGE>

Insurer shall not have any rights hereunder (except pursuant to Section 11.01
and any rights to indemnification hereunder in the case of clause (ii) below) so
long as (i) the NIMS Insurer has not undertaken to guarantee certain payments of
notes issued pursuant to the Indenture or (ii) any default has occurred and is
continuing under the insurance policy issued by the NIMS Insurer with respect to
such notes.

                                      -48-

<PAGE>

                                   ARTICLE II

                          CONVEYANCE OF MORTGAGE LOANS;
                        ORIGINAL ISSUANCE OF CERTIFICATES

                  SECTION 2.01.             Conveyance of the Mortgage Loans.

                  The Depositor, concurrently with the execution and delivery
hereof, does hereby transfer, assign, set over and otherwise convey to the
Trustee without recourse, for the benefit of the Certificateholders, all the
right, title and interest of the Depositor, including any security interest
therein for the benefit of the Depositor, in and to the Mortgage Loans
identified on the Mortgage Loan Schedule, the rights of the Depositor under the
Mortgage Loan Purchase Agreement, and all other assets included or to be
included in REMIC I. Such assignment includes all interest and principal
received by the Depositor or the Master Servicer on or with respect to the
Mortgage Loans (other than payments of principal and interest due on such
Mortgage Loans on or before the Cut-off Date). The Depositor herewith delivers
to the Trustee an executed original Mortgage Loan Purchase Agreement and PMI
Policy.

                  In connection with such transfer and assignment, the Depositor
does hereby deliver to, and deposit with, the Trustee the following documents or
instruments with respect to each Mortgage Loan so transferred and assigned (a
"Mortgage File"):

                  (i) the original Mortgage Note, endorsed in blank or in the
         following form: "Pay to the order of Wells Fargo Bank Minnesota,
         National Association, as Trustee under the applicable agreement,
         without recourse," with all prior and intervening endorsements showing
         a complete chain of endorsement from the originator to the Person so
         endorsing to the Trustee;

                  (ii) the original Mortgage with evidence of recording thereon,
         and the original recorded power of attorney, if the Mortgage was
         executed pursuant to a power of attorney, with evidence of recording
         thereon;

                  (iii) an original Assignment in blank;

                  (iv) the original recorded Assignment or Assignments showing a
         complete chain of assignment from the originator to the Person
         assigning the Mortgage to the Trustee as contemplated by the
         immediately preceding clause (iii);

                  (v) the original or copies of each assumption, modification,
         written assurance or substitution agreement, if any; and

                  (vi) the original lender's title insurance policy, together
         with all endorsements or riders that were issued with or subsequent to
         the issuance of such policy, insuring the priority of the Mortgage as a
         first or second lien on the Mortgaged Property represented therein as a
         fee interest vested in the Mortgagor, or in the event such original
         title policy is unavailable, a written commitment or uniform binder or
         preliminary report of title issued by the title

                                      -49-

<PAGE>

         insurance or escrow company.

                  With respect to a maximum of approximately 2.0% of the
Original Mortgage Loans, by outstanding principal balance of the Original
Mortgage Loans as of the Cut-off Date, if any original Mortgage Note referred to
in Section 2.01(i) above cannot be located, the obligations of the Depositor to
deliver such documents shall be deemed to be satisfied upon delivery to the
Trustee of a photocopy of such Mortgage Note, if available, with a lost note
affidavit substantially in the form of Exhibit I attached hereto. If any of the
original Mortgage Notes for which a lost note affidavit was delivered to the
Trustee is subsequently located, such original Mortgage Note shall be delivered
to the Trustee within three Business Days.

                  The Master Servicer, in its capacity as Originator, shall
promptly (within sixty Business Days following the later of the Closing Date and
the date of receipt by the Trustee of the recording information for a Mortgage,
but in no event later than ninety days following the Closing Date) submit or
cause to be submitted for recording, at no expense to the Trust Fund, the
Trustee or the Depositor, in the appropriate public office for real property
records, each Assignment referred to in Sections 2.01(iii) and (iv) above and in
connection therewith, the Master Servicer shall cause each original Assignment
to be executed in the following form: "Wells Fargo Bank Minnesota, National
Association, as Trustee under the applicable agreement." In the event that any
such Assignment is lost or returned unrecorded because of a defect therein, the
Master Servicer shall promptly prepare or cause to be prepared a substitute
Assignment or cure or cause to be cured such defect, as the case may be, and
thereafter cause each such Assignment to be duly recorded.

                  Notwithstanding the foregoing, the Assignments of Mortgage
shall not be required to be submitted for recording (except with respect to any
Mortgage Loan located in Maryland) unless the Depositor is informed by the
Rating Agencies that such failure to record would result in a withdrawal or a
downgrading by any Rating Agency of the rating on any Class of Certificates;
provided, however, each Assignment shall be submitted in the manner described
above, at no expense to the Trust Fund or the Trustee, upon the earliest to
occur of: (i) reasonable direction by the Holders of Certificates entitled to at
least 25% of the Voting Rights or the NIMS Insurer, (ii) the occurrence of a
Master Servicer Event of Default, (iii) the occurrence of a bankruptcy,
insolvency or foreclosure relating to the Originator, (iv) the occurrence of a
servicing transfer as described in Section 7.02 hereof, (v) upon receipt of
notice from the Master Servicer, the occurrence of a bankruptcy, insolvency or
foreclosure relating to the Mortgagor under the related Mortgage and (vi) upon
receipt of notice from the Master Servicer, any Mortgage Loan that is 90 days or
more delinquent. Upon the occurrence of one of the events set forth in the
immediately preceding sentence, the Master Servicer, in its capacity as
Originator, shall deliver such Assignments for recording as provided above,
promptly and in any event within 30 days following receipt of notice by the
Master Servicer.

                  If any of the documents referred to in Sections 2.01(ii),
(iii) or (iv) above has, as of the Closing Date, been submitted for recording
but either (x) has not been returned from the applicable public recording office
or (y) has been lost or such public recording office has retained the original
of such document, the obligations of the Depositor to deliver such documents
shall be deemed to be satisfied upon (1) delivery to the Trustee of a copy of
each such document certified by the Originator in the case of (x) above or the
applicable public recording office in the case of (y)

                                      -50-

<PAGE>

above to be a true and complete copy of the original that was submitted for
recording and (2) if such copy is certified by the Originator, delivery to the
Trustee promptly upon receipt thereof of either the original or a copy of such
document certified by the applicable public recording office to be a true and
complete copy of the original. Pursuant to the Mortgage Loan Purchase Agreement,
notice shall be provided to the Trustee and the Rating Agencies by the
Originator if delivery pursuant to clause (2) above will be made more than 180
days after the Closing Date.

                  If the original lender's title insurance policy was not
delivered pursuant to Section 2.01(vi) above, the Depositor shall deliver or
cause to be delivered to the Trustee, promptly after receipt thereof, the
original lender's title insurance policy. The Depositor shall deliver or cause
to be delivered to the Trustee promptly upon receipt thereof any other original
documents constituting a part of a Mortgage File received with respect to any
Mortgage Loan, including, but not limited to, any original documents evidencing
an assumption or modification of any Mortgage Loan.

                  All original documents relating to the Mortgage Loans that are
not delivered to the Trustee are and shall be held by or on behalf of the
Originator, the Seller, the Depositor or the Master Servicer, as the case may
be, in trust for the benefit of the Trustee on behalf of the Certificateholders.
In the event that any such original document is required pursuant to the terms
of this Section 2.01 to be a part of a Mortgage File, such document shall be
delivered promptly to the Trustee. Any such original document delivered to or
held by the Depositor that is not required pursuant to the terms of this Section
to be a part of a Mortgage File, shall be delivered promptly to the Master
Servicer.

                  SECTION 2.02.             Acceptance of REMIC I by Trustee.

                  The Trustee acknowledges receipt, subject to the provisions of
Section 2.01 and subject to any exceptions noted on the exception report
described in the next paragraph below, the documents referred to in Section 2.01
(other than such documents described in Section 2.01(v)) above and all other
assets included in the definition of "REMIC I" under clauses (i), (iii), (iv)
and (v) (to the extent of amounts deposited into the Distribution Account) and
declares that it holds and will hold such documents and the other documents
delivered to it constituting a Mortgage File, and that it holds or will hold all
such assets and such other assets included in the definition of "REMIC I" in
trust for the exclusive use and benefit of all present and future
Certificateholders.

                  The Trustee agrees to execute and deliver to the Depositor and
the NIMS Insurer on or prior to the Closing Date an acknowledgment of receipt of
the original Mortgage Note (with any exceptions noted), substantially in the
form attached as Exhibit C-3 hereto.

                  The Trustee agrees, for the benefit of the Certificateholders
and the NIMS Insurer, to review each Mortgage File and, within 45 days of the
Closing Date, to certify in substantially the form attached hereto as Exhibit
C-1 that, as to each Mortgage Loan listed in the Mortgage Loan Schedule (other
than any Mortgage Loan paid in full or any Mortgage Loan specifically identified
in the exception report annexed thereto as not being covered by such
certification), (i) all documents constituting part of such Mortgage File (other
than such documents described in Section 2.01(v)) required to be delivered to it
pursuant to this Agreement are in its possession, (ii) such documents have been
reviewed by the Trustee and appear regular on their face and relate to such
Mortgage Loan and (iii) based on the Trustee's examination and only as to the
foregoing, the information set forth

                                      -51-

<PAGE>

in the Mortgage Loan Schedule that corresponds to items (1), (2), (3), (12),
(15) and (18) of the definition of "Mortgage Loan Schedule" accurately reflects
information set forth in the Mortgage File. It is herein acknowledged that, in
conducting such review, the Trustee is under no duty or obligation (i) to
inspect, review or examine any such documents, instruments, certificates or
other papers to determine whether they are genuine, enforceable, or appropriate
for the represented purpose or whether they have actually been recorded or that
they are other than what they purport to be on their face or (ii) to determine
whether any Mortgage File should include any of the documents specified in
clause (v) of Section 2.01.

                  Prior to the first anniversary date of this Agreement the
Trustee shall deliver to the Depositor, the NIMS Insurer and the Master Servicer
a final certification in the form annexed hereto as Exhibit C-2 evidencing the
completeness of the Mortgage Files, with any applicable exceptions noted
thereon, and the Master Servicer shall forward a copy thereof to any
Sub-Servicer.

                  If in the process of reviewing the Mortgage Files and making
or preparing, as the case may be, the certifications referred to above, the
Trustee finds any document or documents constituting a part of a Mortgage File
to be missing or defective in any material respect, at the conclusion of its
review the Trustee shall so notify the Depositor, the NIMS Insurer and the
Master Servicer. In addition, upon the discovery by the Depositor, the NIMS
Insurer, the Master Servicer or the Trustee of a breach of any of the
representations and warranties made by the Originator or the Seller in the
Mortgage Loan Purchase Agreement in respect of any Mortgage Loan which
materially adversely affects such Mortgage Loan or the interests of the related
Certificateholders in such Mortgage Loan, the party discovering such breach
shall give prompt written notice to the other parties.

                  The Trustee shall, at the written request and expense of any
Certificateholder, provide a written report to such Certificateholder of all
Mortgage Files released to the Master Servicer for servicing purposes.

                  The Depositor and the Trustee intend that the assignment and
transfer herein contemplated constitute a sale of the Mortgage Loans, the
related Mortgage Notes and the related documents, conveying good title thereto
free and clear of any liens and encumbrances, from the Depositor to the Trustee
in trust for the benefit of the Certificateholders and that such property not be
part of the Depositor's estate or property of the Depositor in the event of any
insolvency by the Depositor. In the event that such conveyance is deemed to be,
or to be made as security for, a loan, the parties intend that the Depositor
shall be deemed to have granted and does hereby grant to the Trustee a first
priority perfected security interest in all of the Depositor's right, title and
interest in and to the Mortgage Loans, the related Mortgage Notes and the
related documents, and that this Agreement shall constitute a security agreement
under applicable law.

                  SECTION 2.03.             Repurchase or Substitution of
                                            Mortgage Loans by the Originator or
                                            the Seller.

                  (a) Upon discovery or receipt of notice of any materially
defective document in, or that a document is missing from, a Mortgage File or of
the breach by the Originator or the Seller of any representation, warranty or
covenant under the Mortgage Loan Purchase Agreement

                                      -52-

<PAGE>

(including any representation, warranty or covenant regarding the Prepayment
Charge Schedule) in respect of any Mortgage Loan that materially adversely
affects the value of such Mortgage Loan or the interest therein of the
Certificateholders, the Trustee shall promptly notify the Originator, the NIMS
Insurer, the Seller and the Master Servicer of such defect, missing document or
breach and request that the Originator or the Seller, as applicable, deliver
such missing document or cure such defect or breach within 90 days from the date
the Originator or the Seller, as applicable, was notified of such missing
document, defect or breach, and if the Originator or the Seller, as applicable,
does not deliver such missing document or cure such defect or breach in all
material respects during such period, the Master Servicer, to the extent it is
not the Originator, the Seller or an Affiliate of the Seller, and otherwise the
Trustee, in accordance with Section 3.02(b), shall enforce the obligations of
the Originator or the Seller, as applicable, under the Mortgage Loan Purchase
Agreement to repurchase such Mortgage Loan from REMIC I at the Purchase Price
within 90 days after the date on which the Originator or the Seller, as
applicable, was notified (subject to Section 2.03(c)) of such missing document,
defect or breach, if and to the extent that the Originator or the Seller, as
applicable, is obligated to do so under the Mortgage Loan Purchase Agreement.
The Purchase Price for the repurchased Mortgage Loan shall be remitted to the
Master Servicer for deposit in the Collection Account and the Trustee, upon
receipt of written certification from the Master Servicer of such deposit, shall
release to the Originator or the Seller, as applicable, the related Mortgage
File and the Trustee shall execute and deliver such instruments of transfer or
assignment, in each case without recourse, as the Originator or the Seller, as
applicable, shall furnish to it and as shall be necessary to vest in the
Originator or the Seller, as applicable, any Mortgage Loan released pursuant
hereto. The Trustee shall not have any further responsibility with regard to
such Mortgage File. In lieu of repurchasing any such Mortgage Loan as provided
above, if so provided in the Mortgage Loan Purchase Agreement, the Originator or
the Seller, as applicable, may cause such Mortgage Loan to be removed from REMIC
I (in which case it shall become a Deleted Mortgage Loan) and substitute one or
more Qualified Substitute Mortgage Loans in the manner and subject to the
limitations set forth in Section 2.03(b). It is understood and agreed that the
obligation of the Originator or the Seller, as applicable, to cure or to
repurchase (or to substitute for) any Mortgage Loan as to which a document is
missing, a material defect in a constituent document exists or as to which such
a breach has occurred and is continuing shall constitute the sole remedy
respecting such omission, defect or breach available to the Trustee and the
Certificateholders.

                  (b) Any substitution of Qualified Substitute Mortgage Loans
for Deleted Mortgage Loans made pursuant to Section 2.03(a) must be effected
prior to the date which is two years after the Startup Day for REMIC I.

                  As to any Deleted Mortgage Loan for which the Originator or
the Seller, as applicable, substitutes a Qualified Substitute Mortgage Loan or
Loans, such substitution shall be effected by the Originator or the Seller, as
applicable, delivering to the Trustee, for such Qualified Substitute Mortgage
Loan or Loans, the Mortgage Note, the Mortgage, the Assignment to the Trustee,
and such other documents and agreements, with all necessary endorsements
thereon, as are required by Section 2.01, together with an Officers' Certificate
providing that each such Qualified Substitute Mortgage Loan satisfies the
definition thereof and specifying the Substitution Adjustment Amount (as
described below), if any, in connection with such substitution. The Trustee
shall acknowledge receipt for such Qualified Substitute Mortgage Loan or Loans
and, within ten Business Days thereafter, review such documents as specified in
Section 2.02 and deliver to the Depositor,

                                      -53-

<PAGE>

the NIMS Insurer and the Master Servicer, with respect to such Qualified
Substitute Mortgage Loan or Loans, a certification substantially in the form
attached hereto as Exhibit C-1, with any applicable exceptions noted thereon.
Within one year of the date of substitution, the Trustee shall deliver to the
Depositor, the NIMS Insurer and the Master Servicer a certification
substantially in the form of Exhibit C-2 hereto with respect to such Qualified
Substitute Mortgage Loan or Loans, with any applicable exceptions noted thereon.
Monthly Payments due with respect to Qualified Substitute Mortgage Loans in the
month of substitution are not part of REMIC I and will be retained by the
Originator or the Seller, as applicable. For the month of substitution,
distributions to Certificateholders will reflect the Monthly Payment due on such
Deleted Mortgage Loan on or before the Due Date in the month of substitution,
and the Originator or the Seller, as applicable, shall thereafter be entitled to
retain all amounts subsequently received in respect of such Deleted Mortgage
Loan. The Depositor shall give or cause to be given written notice to the
Certificateholders and the NIMS Insurer that such substitution has taken place,
shall amend the Mortgage Loan Schedule to reflect the removal of such Deleted
Mortgage Loan from the terms of this Agreement and the substitution of the
Qualified Substitute Mortgage Loan or Loans and shall deliver a copy of such
amended Mortgage Loan Schedule to the Trustee and the NIMS Insurer. Upon such
substitution, such Qualified Substitute Mortgage Loan or Loans shall constitute
part of the Mortgage Pool and shall be subject in all respects to the terms of
this Agreement and the Mortgage Loan Purchase Agreement, including, all
applicable representations and warranties thereof included in the Mortgage Loan
Purchase Agreement.

                  For any month in which the Originator or the Seller, as
applicable, substitutes one or more Qualified Substitute Mortgage Loans for one
or more Deleted Mortgage Loans, the Master Servicer will determine the amount
(the "Substitution Adjustment Amount"), if any, by which the aggregate Purchase
Price of all such Deleted Mortgage Loans exceeds the aggregate of, as to each
such Qualified Substitute Mortgage Loan, the Principal Balance thereof as of the
date of substitution, together with one month's interest on such Principal
Balance at the applicable Net Mortgage Rate, plus all outstanding Advances and
Servicing Advances (including Nonrecoverable Advances and Nonrecoverable
Servicing Advances) related thereto. On the date of such substitution, the
Originator or the Seller, as applicable, will deliver or cause to be delivered
to the Master Servicer for deposit in the Collection Account an amount equal to
the Substitution Adjustment Amount, if any, and the Trustee, upon receipt of the
related Qualified Substitute Mortgage Loan or Loans and certification by the
Master Servicer of such deposit, shall release to the Originator or the Seller,
as applicable, the related Mortgage File or Files and the Trustee shall execute
and deliver such instruments of transfer or assignment, in each case without
recourse, the Originator or the Seller, as applicable, shall deliver to it and
as shall be necessary to vest therein any Deleted Mortgage Loan released
pursuant hereto.

                  In addition, the Originator or the Seller, as applicable,
shall obtain at its own expense and deliver to the Trustee and the NIMS Insurer
an Opinion of Counsel to the effect that such substitution will not cause (a)
any federal tax to be imposed on any Trust REMIC, including without limitation,
any federal tax imposed on "prohibited transactions" under Section 860F(a)(1) of
the Code or on "contributions after the startup date" under Section 860G(d)(1)
of the Code, or (b) any Trust REMIC to fail to qualify as a REMIC at any time
that any Certificate is outstanding.

                  (c) Upon discovery by the Depositor, the NIMS Insurer, the
Originator, the Seller, the Master Servicer or the Trustee that any Mortgage
Loan does not constitute a "qualified mortgage"

                                      -54-

<PAGE>

within the meaning of Section 860G(a)(3) of the Code, the party discovering such
fact shall within two Business Days give written notice thereof to the other
parties. In connection therewith, the Originator, the Seller or the Depositor
shall repurchase or, subject to the limitations set forth in Section 2.03(b),
substitute one or more Qualified Substitute Mortgage Loans for the affected
Mortgage Loan within 90 days of the earlier of discovery or receipt of such
notice with respect to such affected Mortgage Loan. Such repurchase or
substitution shall be made by (i) the Originator or the Seller, as the case may
be, if the affected Mortgage Loan's status as a non-qualified mortgage is or
results from a breach of any representation, warranty or covenant made by the
Originator or the Seller, as the case may be, under the Mortgage Loan Purchase
Agreement, or (ii) the Depositor, if the affected Mortgage Loan's status as a
non-qualified mortgage is a breach of no representation or warranty. Any such
repurchase or substitution shall be made in the same manner as set forth in
Section 2.03(a). The Trustee shall reconvey to the Depositor, the Originator or
the Seller, as the case may be, the Mortgage Loan to be released pursuant hereto
in the same manner, and on the same terms and conditions, as it would a Mortgage
Loan repurchased for breach of a representation or warranty.

                  SECTION 2.04.             Reserved

                  SECTION 2.05.             Representations, Warranties and
                                            Covenants of the Master Servicer.

                  The Master Servicer hereby represents, warrants and covenants
to the Trustee, for the benefit of the Certificateholders and to the Depositor
that as of the Closing Date or as of such date specifically provided herein:

                  (i) The Master Servicer is duly organized, validly existing,
         and in good standing under the laws of the jurisdiction of its
         formation and has all licenses necessary to carry on its business as
         now being conducted and is licensed, qualified and in good standing in
         the states where the Mortgaged Property is located if the laws of such
         state require licensing or qualification in order to conduct business
         of the type conducted by the Master Servicer or to ensure the
         enforceability or validity of each Mortgage Loan; the Master Servicer
         has the power and authority to execute and deliver this Agreement and
         to perform in accordance herewith; the execution, delivery and
         performance of this Agreement (including all instruments of transfer to
         be delivered pursuant to this Agreement) by the Master Servicer and the
         consummation of the transactions contemplated hereby have been duly and
         validly authorized; this Agreement evidences the valid, binding and
         enforceable obligation of the Master Servicer, subject to applicable
         bankruptcy, insolvency, reorganization, moratorium or other similar
         laws affecting the enforcement of creditors' rights generally; and all
         requisite corporate action has been taken by the Master Servicer to
         make this Agreement valid and binding upon the Master Servicer in
         accordance with its terms;

                  (ii) The consummation of the transactions contemplated by this
         Agreement are in the ordinary course of business of the Master Servicer
         and will not result in the breach of any term or provision of the
         charter or by-laws of the Master Servicer or result in the breach of
         any term or provision of, or conflict with or constitute a default
         under or result in the acceleration of any obligation under, any
         agreement, indenture or loan or credit agreement

                                      -55-

<PAGE>

         or other instrument to which the Master Servicer or its property is
         subject, or result in the violation of any law, rule, regulation,
         order, judgment or decree to which the Master Servicer or its property
         is subject;

                  (iii) The execution and delivery of this Agreement by the
         Master Servicer and the performance and compliance with its obligations
         and covenants hereunder do not require the consent or approval of any
         governmental authority or, if such consent or approval is required, it
         has been obtained;

                  (iv) This Agreement, and all documents and instruments
         contemplated hereby which are executed and delivered by the Master
         Servicer, constitute and will constitute valid, legal and binding
         obligations of the Master Servicer, enforceable in accordance with
         their respective terms, except as the enforcement thereof may be
         limited by applicable bankruptcy laws and general principles of equity;

                  (v)      [Reserved]

                  (vi) The Master Servicer does not believe, nor does it have
         any reason or cause to believe, that it cannot perform each and every
         covenant contained in this Agreement;

                  (vii) There is no action, suit, proceeding or investigation
         pending or, to its knowledge, threatened against the Master Servicer
         that, either individually or in the aggregate, (A) may result in any
         change in the business, operations, financial condition, properties or
         assets of the Master Servicer that might prohibit or materially and
         adversely affect the performance by such Master Servicer of its
         obligations under, or validity or enforceability of, this Agreement, or
         (B)may result in any material impairment of the right or ability of the
         Master Servicer to carry on its business substantially as now
         conducted, or (C) may result in any material liability on the part of
         the Master Servicer, or (D) would draw into question the validity or
         enforceability of this Agreement or of any action taken or to be taken
         in connection with the obligations of the Master Servicer contemplated
         herein, or (E) would otherwise be likely to impair materially the
         ability of the Master Servicer to perform under the terms of this
         Agreement;

                  (viii) Neither this Agreement nor any information, certificate
         of an officer, statement furnished in writing or report delivered to
         the Trustee by the Master Servicer in connection with the transactions
         contemplated hereby contains any untrue statement of a material fact;

                  (ix) The Master Servicer covenants that its computer and other
         systems used in servicing the Mortgage Loans operate in a manner such
         that the Master Servicer can service the Mortgage Loans in accordance
         with the terms of this Agreement;

                  (x) The information set forth in the Prepayment Charge
         Schedule (including the Prepayment Charge Summary attached thereto) is
         complete, true and correct in all material respects on the date or
         dates when such information is furnished and each Prepayment Charge is
         permissible and enforceable in accordance with its terms (except to the
         extent that

                                      -56-

<PAGE>

         the enforceability thereof may be limited by bankruptcy, insolvency,
         moratorium, receivership and other similar laws affecting creditor's
         rights generally or the collectibility thereof may be limited due to
         acceleration in connection with a foreclosure) under applicable state
         law;

                  (xi) The Master Servicer will not waive any Prepayment Charge
         unless it is waived in accordance with the standard set forth in
         Section 3.01; and

                  (xii) The Master Servicer has accurately and fully reported,
         and will continue to accurately and fully report, its borrower credit
         files to each of the credit repositories in a timely manner.

                  It is understood and agreed that the representations,
warranties and covenants set forth in this Section 2.05 shall survive delivery
of the Mortgage Files to the Trustee and shall inure to the benefit of the
Trustee, the Depositor and the Certificateholders. Upon discovery by any of the
Depositor, the Master Servicer, the NIMS Insurer or the Trustee of a breach of
any of the foregoing representations, warranties and covenants which materially
and adversely affects the value of any Mortgage Loan or the interests therein of
the Certificateholders, the party discovering such breach shall give prompt
written notice (but in no event later than two Business Days following such
discovery) to the NIMS Insurer and the Trustee. Subject to Section 7.01, unless
such breach shall not be susceptible of cure within 90 days, the obligation of
the Master Servicer set forth in this Section 2.05 to cure breaches shall
constitute the sole remedy against the Master Servicer available to the
Certificateholders, the Depositor and the Trustee on behalf of the
Certificateholders respecting a breach of the representations, warranties and
covenants contained in this Section 2.05. Notwithstanding the foregoing, within
90 days of the earlier of discovery by the Master Servicer or receipt of notice
by the Master Servicer of the breach of the representation or covenant of the
Master Servicer (in its capacity as Originator) set forth in Sections 2.05(x) or
2.05(xi) above which materially and adversely affects the interests of the
Holders of the Class P Certificates in any Prepayment Charge, the Master
Servicer shall remedy such breach as follows: (a) if the representation made by
the Master Servicer (in its capacity as Originator) in Section 2.05(x) above is
breached and a Principal Prepayment has occurred in the applicable Prepayment
Period or if a change of law subsequent to the Closing Date limits the
enforceability of a Prepayment Charge (other than in the circumstances provided
in Section 2.05(x) above), the Master Servicer (in its capacity as Originator)
must pay the amount of the scheduled Prepayment Charge, for the benefit of the
Holders of the Class P Certificates, by depositing such amount into the
Collection Account, net of any amount previously collected by the Master
Servicer and paid by the Master Servicer, for the benefit of the Holders of the
Class P Certificates, in respect of such Prepayment Charge; and (b) if any of
the covenants made by the Master Servicer in Section 2.05(xi) above is breached,
the Master Servicer must pay the amount of such waived Prepayment Charge, for
the benefit of the Holders of the Class P Certificates, by depositing such
amount into the Collection Account.

                  SECTION 2.06.             Issuance of the REMIC I Regular
                                            Interests and the Class R-I
                                            Interest.

                  The Trustee acknowledges the assignment to it of the Mortgage
Loans and the delivery to it of the Mortgage Files, subject to the provisions of
Section 2.01 and Section 2.02,

                                      -57-

<PAGE>

together with the assignment to it of all other assets included in REMIC I, the
receipt of which is hereby acknowledged. Concurrently with such assignment and
delivery and in exchange therefor, the Trustee, pursuant to the written request
of the Depositor executed by an officer of the Depositor, has executed,
authenticated and delivered to or upon the order of the Depositor, the Class R-I
Interest in authorized denominations. The interests evidenced by the Class R-I
Interest, together with the REMIC I Regular Interests, constitute the entire
beneficial ownership interest in REMIC I. The rights of the Class R-I Interest
and REMIC II (as holder of the REMIC I Regular Interests) to receive
distributions from the proceeds of REMIC I in respect of the Class R-I Interest
and the REMIC I Regular Interests, respectively, and all ownership interests
evidenced or constituted by the Class R-I Interest and the REMIC I Regular
Interests, shall be as set forth in this Agreement.

                  SECTION 2.07.             Conveyance of the REMIC I Regular
                                            Interests; Acceptance of REMIC II by
                                            the Trustee.

                  The Depositor, concurrently with the execution and delivery
hereof, does hereby transfer, assign, set over and otherwise convey to the
Trustee, without recourse all the right, title and interest of the Depositor in
and to the REMIC I Regular Interests for the benefit of the Class R
Certificateholders (as holder of the Class R-I Interest and Class R-II Interest)
and REMIC II (as holder of the REMIC I Regular Interest). The Trustee
acknowledges receipt of the REMIC I Regular Interests and declares that it holds
and will hold the same in trust for the exclusive use and benefit of all present
and future Class R Certificateholders (as holder of the Class R-I Interest and
Class R-II Interest) and REMIC II (as holder of the REMIC I Regular Interests).
The rights of the Class R Certificateholders (as holder of the Class R-I
Interest and Class R-II Interest) and REMIC II (as holder of the REMIC I Regular
Interest) to receive distributions from the proceeds of REMIC II in respect of
the Class R-II Interest and the Certificates, respectively, and all ownership
interests evidenced or constituted by the Class R-II Interest and the REMIC I
Regular Interests, shall be as set forth in this Agreement.

                  SECTION 2.08.             Issuance of Class R Certificates.

                  The Trustee acknowledges the assignment to it of the REMIC I
Regular Interests and, concurrently therewith and in exchange therefor, pursuant
to the written request of the Depositor executed by an officer of the Depositor,
the Trustee has executed, authenticated and delivered to or upon the order of
the Depositor, the Class R Certificates in authorized denominations. The
interests evidenced by the Class R Certificates, together with the REMIC II
Certificates, constitute the entire beneficial ownership interest in REMIC II.

                                      -58-

<PAGE>

                                   ARTICLE III

                          ADMINISTRATION AND SERVICING
                              OF THE MORTGAGE LOANS

                  SECTION 3.01.             Master Servicer to Act as Master
                                            Servicer.

                  The Master Servicer shall service and administer the Mortgage
Loans on behalf of the Trust Fund and in the best interests of and for the
benefit of the Certificateholders (as determined by the Master Servicer in its
reasonable judgment) in accordance with the terms of this Agreement and the
Mortgage Loans and, to the extent consistent with such terms, in the same manner
in which it services and administers similar mortgage loans for its own
portfolio, giving due consideration to customary and usual standards of practice
of mortgage lenders and loan servicers administering similar mortgage loans but
without regard to:

                  (A) any relationship that the Master Servicer, any
         Sub-Servicer or any Affiliate of the Master Servicer or any
         Sub-Servicer may have with the related Mortgagor;

                  (B) the ownership or non-ownership of any Certificate by the
         Master Servicer or any Affiliate of the Master Servicer;

                  (C) the Master Servicer's obligation to make Advances or
         Servicing Advances; or

                  (D) the Master Servicer's or any Sub-Servicer's right to
         receive compensation for its services hereunder or with respect to any
         particular transaction.

                  To the extent consistent with the foregoing, the Master
Servicer (a) shall seek the timely and complete recovery of principal and
interest on the Mortgage Notes and (b) shall waive (or permit a Sub-Servicer to
waive) a Prepayment Charge only under the following circumstances: (i) such
waiver is standard and customary in servicing similar Mortgage Loans and (ii)
either (A) such waiver relates to a default or a reasonably foreseeable default
and would, in the reasonable judgment of the Master Servicer, maximize recovery
of total proceeds taking into account the value of such Prepayment Charge and
the related Mortgage Loan or (B) such waiver is made in connection with a
refinancing of the related Mortgage Loan unrelated to a default or a reasonably
foreseeable default where (x) the related mortgagor has stated to the Master
Servicer or an applicable Sub- Servicer an intention to refinance the related
Mortgage Loan and (y) the Master Servicer has concluded in its reasonable
judgement that the waiver of such Prepayment Charge would induce such mortgagor
to refinance with the Master Servicer; provided, however, that the Master
Servicer shall waive no more than 5.00% of the Prepayment Charges (by number of
Prepayment Charges) set forth on the Prepayment Charge Schedule in accordance
with clause (ii)(B) above. If a Prepayment Charge is waived as permitted by
meeting the standards described in clauses (i) and (ii)(B) above, then the
Master Servicer is required to pay the amount of such waived Prepayment Charge,
for the benefit of the Holders of the Class P Certificates, by depositing such
amount into the Collection Account together with and at the time that the amount
prepaid on the related Mortgage Loan is required to be deposited into the
Collection Account. Notwithstanding any other provisions of this

                                      -59-

<PAGE>

Agreement, any payments made by the Master Servicer in respect of any waived
Prepayment Charges pursuant to clauses (i) and (ii)(B) above shall be deemed to
be paid outside of the Trust Fund. Subject only to the above-described servicing
standards and the terms of this Agreement and of the Mortgage Loans, the Master
Servicer shall have full power and authority, acting alone or through
Sub-Servicers as provided in Section 3.02, to do or cause to be done any and all
things in connection with such servicing and administration which it may deem
necessary or desirable. Without limiting the generality of the foregoing, the
Master Servicer in its own name or in the name of a Sub-Servicer is hereby
authorized and empowered by the Trustee when the Master Servicer believes it
appropriate in its best judgment in accordance with the servicing standards set
forth above, to execute and deliver, on behalf of the Certificateholders and the
Trustee, and upon notice to the Trustee, any and all instruments of satisfaction
or cancellation, or of partial or full release or discharge, and all other
comparable instruments, with respect to the Mortgage Loans and the Mortgaged
Properties and to institute foreclosure proceedings or obtain a deed-in-lieu of
foreclosure so as to convert the ownership of such properties, and to hold or
cause to be held title to such properties, on behalf of the Trustee and
Certificateholders. The Master Servicer shall service and administer the
Mortgage Loans in accordance with applicable state and federal law and shall
provide to the Mortgagors any reports required to be provided to them thereby.
The Master Servicer shall also comply in the performance of this Agreement with
all reasonable rules and requirements of each insurer under any standard hazard
insurance policy. Subject to Section 3.17, within 15 days of the Closing Date,
the Trustee shall execute, at the written request of the Master Servicer, and
furnish to the Master Servicer and any Sub-Servicer any special or limited
powers of attorney for each county in which a Mortgaged Property is located and
other documents necessary or appropriate to enable the Master Servicer or any
Sub-Servicer to carry out their servicing and administrative duties hereunder;
provided, such limited powers of attorney or other documents shall be prepared
by the Master Servicer and submitted to the Trustee for execution. The Trustee
shall not be liable for the actions of the Master Servicer or any Sub-Servicers
under such powers of attorney.

                  Subject to Section 3.09 hereof, in accordance with the
standards of the preceding paragraph, the Master Servicer shall advance or cause
to be advanced funds as necessary for the purpose of effecting the timely
payment of taxes and assessments on the Mortgaged Properties, which advances
shall be Servicing Advances reimbursable in the first instance from related
collections from the Mortgagors pursuant to Section 3.09, and further as
provided in Section 3.11. Any cost incurred by the Master Servicer or by
Sub-Servicers in effecting the timely payment of taxes and assessments on a
Mortgaged Property shall not, for the purpose of calculating distributions to
Certificateholders, be added to the unpaid Principal Balance of the related
Mortgage Loan, notwithstanding that the terms of such Mortgage Loan so permit.

                  Notwithstanding anything in this Agreement to the contrary,
the Master Servicer may not make any future advances with respect to a Mortgage
Loan (except as provided in Section 4.03) and the Master Servicer shall not (i)
permit any modification with respect to any Mortgage Loan that would change the
Mortgage Rate, reduce or increase the Principal Balance (except for reductions
resulting from actual payments of principal) or change the final maturity date
on such Mortgage Loan (unless, as provided in Section 3.07, the Mortgagor is in
default with respect to the Mortgage Loan or such default is, in the judgment of
the Master Servicer, reasonably foreseeable) or (ii) permit any modification,
waiver or amendment of any term of any Mortgage Loan that would both (A) effect
an exchange or reissuance of such Mortgage Loan under Section 1001 of the Code
(or Treasury

                                      -60-

<PAGE>

regulations promulgated thereunder) and (B) cause any REMIC created hereunder to
fail to qualify as a REMIC under the Code or the imposition of any tax on
"prohibited transactions" or "contributions after the startup date" under the
REMIC Provisions.

                  SECTION 3.02.             Sub-Servicing Agreements Between
                                            Master Servicer and Sub- Servicers.

                  (a) The Master Servicer may enter into Sub-Servicing
Agreements with Sub- Servicers for the servicing and administration of the
Mortgage Loans; provided, however, that (i) such agreements would not result in
a withdrawal or a downgrading by any Rating Agency of the rating on any Class of
Certificates and (ii) the NIMS Insurer shall have consented to such Sub-
Servicing Agreement. The Trustee is hereby authorized to acknowledge, at the
request of the Master Servicer, any Sub-Servicing Agreement that meets the
requirements applicable to Sub-Servicing Agreements set forth in this Agreement
and that is otherwise permitted under this Agreement.

                  Each Sub-Servicer shall be (i) authorized to transact business
in the state or states where the related Mortgaged Properties it is to service
are situated, if and to the extent required by applicable law to enable the
Sub-Servicer to perform its obligations hereunder and under the Sub- Servicing
Agreement and (ii) a Freddie Mac or Fannie Mae approved mortgage servicer. Each
Sub- Servicing Agreement must impose on the Sub-Servicer requirements conforming
to the provisions set forth in Section 3.08 and provide for servicing of the
Mortgage Loans consistent with the terms of this Agreement. The Master Servicer
will examine each Sub-Servicing Agreement and will be familiar with the terms
thereof. The terms of any Sub-Servicing Agreement will not be inconsistent with
any of the provisions of this Agreement. The Master Servicer and the
Sub-Servicers may enter into and make amendments to the Sub-Servicing Agreements
or enter into different forms of Sub- Servicing Agreements; provided, however,
that any such amendments or different forms shall be consistent with and not
violate the provisions of this Agreement, and that no such amendment or
different form shall be made or entered into which could be reasonably expected
to be materially adverse to the interests of the Certificateholders without the
consent of the Holders of Certificates entitled to at least 66% of the Voting
Rights; provided, further, that the consent of the Holders of Certificates
entitled to at least 66% of the Voting Rights shall not be required (i) to cure
any ambiguity or defect in a Sub-Servicing Agreement, (ii) to correct, modify or
supplement any provisions of a Sub-Servicing Agreement, or (iii) to make any
other provisions with respect to matters or questions arising under a
Sub-Servicing Agreement, which, in each case, shall not be inconsistent with the
provisions of this Agreement. Any variation without the consent of the Holders
of Certificates entitled to at least 66% of the Voting Rights from the
provisions set forth in Section 3.08 relating to insurance or priority
requirements of Sub-Servicing Accounts, or credits and charges to the
Sub-Servicing Accounts or the timing and amount of remittances by the
Sub-Servicers to the Master Servicer, are conclusively deemed to be inconsistent
with this Agreement and therefore prohibited. The Master Servicer shall deliver
to the NIMS Insurer and the Trustee copies of all Sub- Servicing Agreements, and
any amendments or modifications thereof, promptly upon the Master Servicer's
execution and delivery of such instruments.

                  (b) As part of its servicing activities hereunder, the Master
Servicer, for the benefit of the Trustee and the Certificateholders, shall
enforce the obligations of each Sub-Servicer under the related Sub-Servicing
Agreement and of the Originator and the Seller under the Mortgage

                                      -61-

<PAGE>

Loan Purchase Agreement, including, without limitation, any obligation to make
advances in respect of delinquent payments as required by a Sub-Servicing
Agreement, or to purchase a Mortgage Loan on account of missing or defective
documentation or on account of a breach of a representation, warranty or
covenant, as described in Section 2.03(a). Such enforcement, including, without
limitation, the legal prosecution of claims, termination of Sub-Servicing
Agreements, and the pursuit of other appropriate remedies, shall be in such form
and carried out to such an extent and at such time as the Master Servicer, in
its good faith business judgment, would require were it the owner of the related
Mortgage Loans. The Master Servicer shall pay the costs of such enforcement at
its own expense, and shall be reimbursed therefor only (i) from a general
recovery resulting from such enforcement, to the extent, if any, that such
recovery exceeds all amounts due in respect of the related Mortgage Loans, or
(ii) from a specific recovery of costs, expenses or attorneys' fees against the
party against whom such enforcement is directed. Enforcement of the Mortgage
Loan Purchase Agreement against the Originator or the Seller shall be effected
by the Master Servicer to the extent it is not the Originator, and otherwise by
the Trustee in accordance with the foregoing provisions of this paragraph.

                  SECTION 3.03.             Successor Sub-Servicers.

                  The Master Servicer, with the consent of the NIMS Insurer,
shall be entitled to terminate any Sub-Servicing Agreement and the rights and
obligations of any Sub-Servicer pursuant to any Sub-Servicing Agreement in
accordance with the terms and conditions of such Sub-Servicing Agreement. In the
event of termination of any Sub-Servicer, all servicing obligations of such Sub-
Servicer shall be assumed simultaneously by the Master Servicer without any act
or deed on the part of such Sub-Servicer or the Master Servicer, and the Master
Servicer either shall service directly the related Mortgage Loans or shall enter
into a Sub-Servicing Agreement with a successor Sub-Servicer which qualifies
under Section 3.02.

                  Any Sub-Servicing Agreement shall include the provision that
such agreement may be immediately terminated by the Trustee (if the Trustee is
acting as Master Servicer) without fee, in accordance with the terms of this
Agreement, in the event that the Master Servicer (or the Trustee, if such party
is then acting as Master Servicer) shall, for any reason, no longer be the
Master Servicer (including termination due to a Master Servicer Event of
Termination).

                  SECTION 3.04.             Liability of the Master Servicer.

                  Notwithstanding any Sub-Servicing Agreement or the provisions
of this Agreement relating to agreements or arrangements between the Master
Servicer and a Sub-Servicer or reference to actions taken through a Sub-Servicer
or otherwise, the Master Servicer shall remain obligated and primarily liable to
the Trustee and the Certificateholders for the servicing and administering of
the Mortgage Loans in accordance with the provisions of Section 3.01 without
diminution of such obligation or liability by virtue of such Sub-Servicing
Agreements or arrangements or by virtue of indemnification from the Sub-Servicer
and to the same extent and under the same terms and conditions as if the Master
Servicer alone were servicing and administering the Mortgage Loans. The Master
Servicer shall be entitled to enter into any agreement with a Sub-Servicer for
indemnification of the Master Servicer by such Sub-Servicer and nothing
contained in this Agreement shall be deemed to limit or modify such
indemnification.

                                      -62-

<PAGE>

                  SECTION 3.05.             No Contractual Relationship Between
                                            Sub-Servicers and the NIMS Insurer,
                                            the Trustee or Certificateholders.

                  Any Sub-Servicing Agreement that may be entered into and any
transactions or services relating to the Mortgage Loans involving a Sub-Servicer
in its capacity as such shall be deemed to be between the Sub-Servicer and the
Master Servicer alone, and the NIMS Insurer, the Trustee or Certificateholders
shall not be deemed parties thereto and shall have no claims, rights,
obligations, duties or liabilities with respect to the Sub-Servicer except as
set forth in Section 3.06. The Master Servicer shall be solely liable for all
fees owed by it to any Sub-Servicer, irrespective of whether the Master
Servicer's compensation pursuant to this Agreement is sufficient to pay such
fees.

                  SECTION 3.06.             Assumption or Termination of
                                            Sub-Servicing Agreements by Trustee.

                  In the event the Master Servicer shall for any reason no
longer be the servicer (including by reason of the occurrence of a Master
Servicer Event of Termination), the Trustee shall thereupon assume all of the
rights and obligations of the Master Servicer under each Sub-Servicing Agreement
that the Master Servicer may have entered into, unless the Trustee elects to
terminate any Sub-Servicing Agreement in accordance with its terms as provided
in Section 3.03. Upon such assumption, the Trustee (or the successor servicer
appointed pursuant to Section 7.02) shall be deemed, subject to Section 3.03, to
have assumed all of the departing Master Servicer's interest therein and to have
replaced the departing Master Servicer as a party to each Sub-Servicing
Agreement to the same extent as if each Sub-Servicing Agreement had been
assigned to the assuming party, except that (i) the departing Master Servicer
shall not thereby be relieved of any liability or obligations under any
Sub-Servicing Agreement that arose before it ceased to be the Master Servicer
and (ii) neither the Trustee nor any successor Master Servicer shall be deemed
to have assumed any liability or obligation of the Master Servicer that arose
before it ceased to be the Master Servicer.

                  The Master Servicer at its expense shall, upon request of
Trustee, deliver to the assuming party all documents and records relating to
each Sub-Servicing Agreement and the Mortgage Loans then being serviced and an
accounting of amounts collected and held by or on behalf of it, and otherwise
use its best efforts to effect the orderly and efficient transfer of the Sub-
Servicing Agreements to the assuming party. All Servicing Transfer Costs shall
be paid by the predecessor Master Servicer upon presentation of reasonable
documentation of such costs, and if such predecessor Master Servicer defaults in
its obligation to pay such costs, such costs shall be paid by the successor
Master Servicer or the Trustee (in which case the successor Master Servicer or
the Trustee, as applicable, shall be entitled to reimbursement therefor from the
assets of the Trust Fund).

                  SECTION 3.07.             Collection of Certain Mortgage Loan
                                            Payments.

                  The Master Servicer shall make reasonable efforts to collect
all payments called for under the terms and provisions of the Mortgage Loans,
and shall, to the extent such procedures shall be consistent with this Agreement
and the terms and provisions of any applicable insurance policies, follow such
collection procedures as it would follow with respect to mortgage loans
comparable to

                                      -63-

<PAGE>

the Mortgage Loans and held for its own account. Consistent with the foregoing,
the Master Servicer may in its discretion (i) waive any late payment charge or,
if applicable, any penalty interest, or (ii) extend the due dates for the
Monthly Payments due on a Mortgage Note for a period of not greater than 180
days; provided, however, that any extension pursuant to clause (ii) above shall
not affect the amortization schedule of any Mortgage Loan for purposes of any
computation hereunder, except as provided below; provided further that the NIMS
Insurer's prior written consent shall be required for any modification, waiver
or amendment if the amendment if the aggregate number of outstanding Mortgage
Loans which have been modified, waived or amended exceeds 5% of the number of
Mortgage Loans as of the Cut-off Date. In the event of any such arrangement
pursuant to clause (ii) above, the Master Servicer shall make timely advances on
such Mortgage Loan during such extension pursuant to Section 4.03 and in
accordance with the amortization schedule of such Mortgage Loan without
modification thereof by reason of such arrangement. Notwithstanding the
foregoing, in the event that any Mortgage Loan is in default or, in the judgment
of the Master Servicer, such default is reasonably foreseeable, the Master
Servicer, consistent with the standards set forth in Section 3.01, may also
waive, modify or vary any term of such Mortgage Loan (including modifications
that would change the Mortgage Rate, forgive the payment of principal or
interest or extend the final maturity date of such Mortgage Loan), accept
payment from the related Mortgagor of an amount less than the Stated Principal
Balance in final satisfaction of such Mortgage Loan, or consent to the
postponement of strict compliance with any such term or otherwise grant
indulgence to any Mortgagor (any and all such waivers, modifications, variances,
forgiveness of principal or interest, postponements, or indulgences collectively
referred to herein as "forbearance"), provided, however, that in no event shall
the Master Servicer grant any such forbearance (other than as permitted by the
second sentence of this Section) with respect to any one Mortgage Loan more than
once in any 12 month period or more than three times over the life of such
Mortgage Loan, and provided, further, that in determining which course of action
permitted by this sentence it shall pursue, the Master Servicer shall adhere to
the Loss Mitigation Procedures. The Master Servicer's analysis supporting any
forbearance and the conclusion that any forbearance meets the standards of
Section 3.01 and the Loss Mitigation Procedures shall be reflected in writing in
the Mortgage File.

                  SECTION 3.08.             Sub-Servicing Accounts.

                  In those cases where a Sub-Servicer is servicing a Mortgage
Loan pursuant to a Sub- Servicing Agreement, the Sub-Servicer will be required
to establish and maintain one or more accounts (collectively, the "Sub-Servicing
Account"). The Sub-Servicing Account shall be an Eligible Account and shall
comply with all requirements of this Agreement relating to the Collection
Account. The Sub-Servicer shall deposit in the clearing account in which it
customarily deposits payments and collections on mortgage loans in connection
with its mortgage loan servicing activities on a daily basis, and in no event
more than one Business Day after the Sub-Servicer's receipt thereof, all
proceeds of Mortgage Loans received by the Sub-Servicer less its servicing
compensation to the extent permitted by the Sub-Servicing Agreement, and shall
thereafter deposit such amounts in the Sub-Servicing Account, in no event more
than two Business Days after the receipt of such amounts. The Sub-Servicer shall
thereafter deposit such proceeds in the Collection Account or remit such
proceeds to the Master Servicer for deposit in the Collection Account not later
than two Business Days after the deposit of such amounts in the Sub-Servicing
Account. For purposes of this Agreement, the Master Servicer shall be deemed to
have received payments on the Mortgage Loans when the Sub-Servicer receives such
payments.

                                                       -64-

<PAGE>

                  SECTION 3.09.             Collection of Taxes, Assessments and
                                            Similar Items; Servicing Accounts.

                  The Master Servicer shall establish and maintain, or cause to
be established and maintained, one or more accounts (the "Servicing Accounts"),
into which all Escrow Payments shall be deposited and retained. Servicing
Accounts shall be Eligible Accounts. The Master Servicer shall deposit in the
clearing account in which it customarily deposits payments and collections on
mortgage loans in connection with its mortgage loan servicing activities on a
daily basis, and in no event more than one Business Day after the Master
Servicer's receipt thereof, all Escrow Payments collected on account of the
Mortgage Loans and shall thereafter deposit such Escrow Payments in the
Servicing Accounts, in no event more than two Business Days after the receipt of
such Escrow Payments, all Escrow Payments collected on account of the Mortgage
Loans for the purpose of effecting the timely payment of any such items as
required under the terms of this Agreement. Withdrawals of amounts from a
Servicing Account may be made only to (i) effect payment of taxes, assessments,
hazard insurance premiums, and comparable items in a manner and at a time that
assures that the lien priority of the Mortgage is not jeopardized (or, with
respect to the payment of taxes, in a manner and at a time that avoids the loss
of the Mortgaged Property due to a tax sale or the foreclosure as a result of a
tax lien); (ii) reimburse the Master Servicer (or a Sub-Servicer to the extent
provided in the related Sub-Servicing Agreement) out of related collections for
any Servicing Advances made pursuant to Section 3.01 (with respect to taxes and
assessments) and Section 3.14 (with respect to hazard insurance); (iii) refund
to Mortgagors any sums as may be determined to be overages; (iv) pay interest,
if required and as described below, to Mortgagors on balances in the Servicing
Account; or (v) clear and terminate the Servicing Account at the termination of
the Master Servicer's obligations and responsibilities in respect of the
Mortgage Loans under this Agreement in accordance with Article IX. In the event
the Master Servicer shall deposit in a Servicing Account any amount not required
to be deposited therein, it may at any time withdraw such amount from such
Servicing Account, any provision herein to the contrary notwithstanding. The
Master Servicer will be responsible for the administration of the Servicing
Accounts and will be obligated to make Servicing Advances to such accounts when
and as necessary to avoid the lapse of insurance coverage on the Mortgaged
Property, or which the Master Servicer knows, or in the exercise of the required
standard of care of the Master Servicer hereunder should know, is necessary to
avoid the loss of the Mortgaged Property due to a tax sale or the foreclosure as
a result of a tax lien. If any such payment has not been made and the Master
Servicer receives notice of a tax lien with respect to the Mortgage being
imposed, the Master Servicer will, within 10 business days of such notice,
advance or cause to be advanced funds necessary to discharge such lien on the
Mortgaged Property. As part of its servicing duties, the Master Servicer or
Sub-Servicers shall pay to the Mortgagors interest on funds in the Servicing
Accounts, to the extent required by law and, to the extent that interest earned
on funds in the Servicing Accounts is insufficient, to pay such interest from
its or their own funds, without any reimbursement therefor. The Master Servicer
may pay to itself any excess interest on funds in the Servicing Accounts, to the
extent such action is in conformity with the Servicing Standard, is permitted by
law and such amounts are not required to be paid to Mortgagors or used for any
of the other purposes set forth above.

                                      -65-

<PAGE>

                  SECTION 3.10.             Collection Account and Distribution
                                            Account.

                  (a) On behalf of the Trust Fund, the Master Servicer shall
establish and maintain, or cause to be established and maintained, one or more
accounts (such account or accounts, the "Collection Account"), held in trust for
the benefit of the Trustee and the Certificateholders. On behalf of the Trust
Fund, the Master Servicer shall deposit or cause to be deposited in the clearing
account in which it customarily deposits payments and collections on mortgage
loans in connection with its mortgage loan servicing activities on a daily
basis, and in no event more than one Business Day after the Master Servicer's
receipt thereof, and shall thereafter deposit in the Collection Account, in no
event more than two Business Days after the Master Servicer's receipt thereof,
as and when received or as otherwise required hereunder, the following payments
and collections received or made by it subsequent to the Cut-off Date (other
than in respect of principal or interest on the Mortgage Loans due on or before
the Cut-off Date) or payments (other than Principal Prepayments) received by it
on or prior to the Cut-off Date, but allocable to a Due Period subsequent
thereto:

                  (i) all payments on account of principal, including Principal
         Prepayments (but not Prepayment Charges), on the Mortgage Loans;

                  (ii) all payments on account of interest (net of the related
         Servicing Fee) on each Mortgage Loan;

                  (iii) all Insurance Proceeds, Liquidation Proceeds and
         condemnation proceeds (other than proceeds collected in respect of any
         particular REO Property and amounts paid in connection with a purchase
         of Mortgage Loans and REO Properties pursuant to Section 9.01);

                  (iv) any amounts required to be deposited pursuant to Section
         3.12 in connection with any losses realized on Permitted Investments
         with respect to funds held in the Collection Account;

                  (v) any amounts required to be deposited by the Master
         Servicer pursuant to the second paragraph of Section 3.14(a) in respect
         of any blanket policy deductibles;

                  (vi) all proceeds of any Mortgage Loan repurchased or
         purchased in accordance with Section 2.03 or Section 9.01;

                  (vii) all amounts required to be deposited in connection with
         Substitution Adjustments pursuant to Section 2.03;

                  (viii) all Prepayment Charges collected by the Master Servicer
         and any Master Servicer Prepayment Charge Payment Amounts in connection
         with the Principal Prepayment of any of the Mortgage Loans; and

                  (ix) without duplication, all payments of claims under the PMI
         Policy.

                                      -66-

<PAGE>

                  The foregoing requirements for deposit in the Collection
Account shall be exclusive, it being understood and agreed that, without
limiting the generality of the foregoing, payments in the nature of Servicing
Fees, late payment charges, assumption fees, insufficient funds charges and
ancillary income (other than Prepayment Charges) need not be deposited by the
Master Servicer in the Collection Account and may be retained by the Master
Servicer as additional compensation. In the event the Master Servicer shall
deposit in the Collection Account any amount not required to be deposited
therein, it may at any time withdraw such amount from the Collection Account,
any provision herein to the contrary notwithstanding.

                  (b) On behalf of the Trust Fund, the Trustee shall establish
and maintain one or more accounts (such account or accounts, the "Distribution
Account"), held in trust for the benefit of the Trustee and the
Certificateholders. On behalf of the Trust Fund, the Master Servicer shall
deliver to the Trustee in immediately available funds for deposit in the
Distribution Account on or before 1:00 p.m. New York time (i) on the Master
Servicer Remittance Date, that portion of the Available Funds (calculated
without regard to the references in the definition thereof to amounts that may
be withdrawn from the Distribution Account) for the related Distribution Date
then on deposit in the Collection Account, the amount of all Prepayment Charges
collected during the applicable Prepayment Period by the Master Servicer and
Master Servicer Prepayment Charge Payment Amounts in connection with the
Principal Prepayment of any of the Mortgage Loans then on deposit in the
Collection Account and the amount of any funds reimbursable to an Advancing
Person pursuant to Section 3.29, and (ii) on each Business Day as of the
commencement of which the balance on deposit in the Collection Account exceeds
$75,000 following any withdrawals pursuant to the next succeeding sentence, the
amount of such excess, but only if the Collection Account constitutes an
Eligible Account solely pursuant to clause (ii) of the definition of "Eligible
Account." If the balance on deposit in the Collection Account exceeds $75,000 as
of the commencement of business on any Business Day and the Collection Account
constitutes an Eligible Account solely pursuant to clause (ii) of the definition
of "Eligible Account," the Master Servicer shall, on or before 1:00 p.m. New
York time on such Business Day, withdraw from the Collection Account any and all
amounts payable or reimbursable to the Master Servicer, the Trustee, the
Originator or any Sub- Servicer pursuant to Section 3.11 and shall pay such
amounts to the Persons entitled thereto.

                  (c) Funds in the Collection Account and the Distribution
Account may be invested in Permitted Investments in accordance with the
provisions set forth in Section 3.12. The Master Servicer shall give notice to
the NIMS Insurer and the Trustee of the location of the Collection Account
maintained by it when established and prior to any change thereof. The Trustee
shall give notice to the NIMS Insurer, the Master Servicer and the Depositor of
the location of the Distribution Account when established and prior to any
change thereof.

                  (d) Funds held in the Collection Account at any time may be
delivered by the Master Servicer to the Trustee for deposit in an account (which
may be the Distribution Account and must satisfy the standards for the
Distribution Account as set forth in the definition thereof) and for all
purposes of this Agreement shall be deemed to be a part of the Collection
Account; provided, however, that the Trustee shall have the sole authority to
withdraw any funds held pursuant to this subsection (d). In the event the Master
Servicer shall deliver to the Trustee for deposit in the Distribution Account
any amount not required to be deposited therein, it may at any time request that
the Trustee withdraw such amount from the Distribution Account and remit to it
any such amount,

                                      -67-

<PAGE>

any provision herein to the contrary notwithstanding. In addition, the Master
Servicer, with respect to items (i) through (iv) below, shall deliver to the
Trustee from time to time for deposit, and the Trustee, with respect to items
(i) through (iv) below, shall so deposit, in the Distribution Account:

                  (i) any Advances, as required pursuant to Section 4.03;

                  (ii) any amounts required to be deposited pursuant to Section
                  3.23(d) or (f) in connection with any REO Property;

                  (iii) any amounts to be paid in connection with a purchase of
                  Mortgage Loans and REO Properties pursuant to Section 9.01;

                  (iv) any Compensating Interest to be deposited pursuant to
                  Section 3.24 in connection with any Prepayment Interest
                  Shortfall; and

                  (v) any amounts required to be paid to the Trustee pursuant to
                  the Agreement, including, but not limited to Section 3.06 and
                  Section 7.02.

                  (e) The Master Servicer shall deposit in the Collection
Account any amounts required to be deposited pursuant to Section 3.12(b) in
connection with losses realized on Permitted Investments with respect to funds
held in the Collection Account.

                  SECTION 3.11.             Withdrawals from the Collection
                                            Account and Distribution Account.

                  (a) The Master Servicer shall, from time to time, make
withdrawals from the Collection Account for any of the following purposes or as
described in Section 4.03:

                  (i) to remit to the Trustee for deposit in the Distribution
         Account the amounts required to be so remitted pursuant to Section
         3.10(b) or permitted to be so remitted pursuant to the first sentence
         of Section 3.10(d);

                  (ii) subject to Section 3.16(d), to reimburse the Master
         Servicer for (a) any unreimbursed Advances to the extent of amounts
         received which represent Late Collections (net of the related Servicing
         Fees) of Monthly Payments, Liquidation Proceeds and Insurance Proceeds
         on Mortgage Loans with respect to which such Advances were made in
         accordance with the provisions of Section 4.03; or (b) any unreimbursed
         Advances with respect to the final liquidation of a Mortgage Loan that
         are Nonrecoverable Advances, but only to the extent that Late
         Collections, Liquidation Proceeds and Insurance Proceeds received with
         respect to such Mortgage Loan are insufficient to reimburse the Master
         Servicer for such unreimbursed Advances;

                  (iii) subject to Section 3.16(d), to pay the Master Servicer
         or any Sub-Servicer (a) any unpaid Servicing Fees, (b) any unreimbursed
         Servicing Advances with respect to each Mortgage Loan, but only to the
         extent of any Late Collections, Liquidation Proceeds, Insurance
         Proceeds and condemnation proceeds received with respect to such
         Mortgage

                                      -68-

<PAGE>

         Loan, and (c) any Servicing Advances with respect to the final
         liquidation of a Mortgage Loan that are Nonrecoverable Advances, but
         only to the extent that Late Collections, Liquidation Proceeds and
         Insurance Proceeds received with respect to such Mortgage Loan are
         insufficient to reimburse the Master Servicer or any Sub-Servicer for
         Servicing Advances;

                  (iv) to pay to the Master Servicer as servicing compensation
         (in addition to the Servicing Fee) on the Master Servicer Remittance
         Date any interest or investment income earned on funds deposited in the
         Collection Account;

                  (v) to pay to the Originator, with respect to each Mortgage
         Loan that has previously been purchased or replaced pursuant to Section
         2.03 or Section 3.16(c) all amounts received thereon subsequent to the
         date of purchase or substitution, as the case may be;

                  (vi) to reimburse the Master Servicer for any Advance or
         Servicing Advance previously made which the Master Servicer has
         determined to be a Nonrecoverable Advance in accordance with the
         provisions of Section 4.03;

                  (vii) to pay, or to reimburse the Master Servicer for
         Servicing Advances in respect of, expenses incurred in connection with
         any Mortgage Loan pursuant to Section 3.16(b);

                  (viii) to reimburse the Master Servicer for expenses incurred
         by or reimbursable to the Master Servicer pursuant to Section 6.03;

                  (ix) to reimburse the NIMS Insurer, the Master Servicer (if
         the Master Servicer is not an Affiliate of the Originator) or the
         Trustee, as the case may be, for enforcement expenses reasonably
         incurred in respect of the breach or defect giving rise to the purchase
         obligation under Section 2.03 of this Agreement that were included in
         the Purchase Price of the Mortgage Loan, including any expenses arising
         out of the enforcement of the purchase obligation;

                  (x) to pay itself any Prepayment Interest Excess; and

                  (xi) to clear and terminate the Collection Account pursuant to
         Section 9.01.

                  The foregoing requirements for withdrawal from the Collection
Account shall be exclusive. In the event the Master Servicer shall deposit in
the Collection Account any amount not required to be deposited therein, it may
at any time withdraw such amount from the Collection Account, any provision
herein to the contrary notwithstanding.

                  The Master Servicer shall keep and maintain separate
accounting, on a Mortgage Loan by Mortgage Loan basis, for the purpose of
justifying any withdrawal from the Collection Account, to the extent held by or
on behalf of it, pursuant to subclauses (ii), (iii), (iv), (v), (vi), (vii) and
(viii) above. The Master Servicer shall provide written notification to the NIMS
Insurer and the Trustee, on or prior to the next succeeding Master Servicer
Remittance Date, upon making any

                                      -69-

<PAGE>

withdrawals from the Collection Account pursuant to subclause (vi) above;
provided that an Officers' Certificate in the form described under Section
4.03(d) shall suffice for such written notification to the Trustee in respect
hereof.

                  (b) The Trustee shall, from time to time, make withdrawals
from the Distribution Account, for any of the following purposes, without
priority:

                  (i) to make distributions in accordance with Section 4.01;

                  (ii) to pay itself the Trustee Fee and any Extraordinary Trust
         Fund Expenses pursuant to Section 8.05;

                  (iii) to pay any amounts in respect of taxes pursuant to
         Section 10.01(g);

                  (iv) to clear and terminate the Distribution Account pursuant
         to Section 9.01;

                  (v) to pay any amounts required to be paid to the Trustee
         pursuant to this Agreement, including but not limited to funds required
         to be paid pursuant to Section 3.06 and Section 7.02;

                  (vi) to pay to the Trustee, any interest or investment income
         earned on funds deposited in the Distribution Account;

                  (vii) to pay to an Advancing Person reimbursements for
         Advances and/or Servicing Advances pursuant to Section 3.29; and

                  (viii) to pay the PMI Insurer the PMI Insurer Fee.

                  SECTION 3.12.             Investment of Funds in the
                                            Collection Account and the
                                            Distribution Account.

                  (a) The Master Servicer may direct any depository institution
maintaining the Collection Account and any REO Account to invest the funds on
deposit in such accounts, and the Trustee may invest the funds on deposit in the
Distribution Account (each such account, for the purposes of this Section 3.12
an "Investment Account"). All investments pursuant to this Section 3.12 shall be
in one or more Permitted Investments bearing interest or sold at a discount, and
maturing, unless payable on demand, (i) no later than the Business Day
immediately preceding the date on which such funds are required to be withdrawn
from such account pursuant to this Agreement, if a Person other than the Trustee
is the obligor thereon or if such investment is managed or advised by a Person
other than the Trustee or an Affiliate of the Trustee, and (ii) no later than
the date on which such funds are required to be withdrawn from such account
pursuant to this Agreement, if the Trustee is the obligor thereon or if such
investment is managed or advised by the Trustee or any Affiliate. All such
Permitted Investments shall be held to maturity, unless payable on demand. Any
investment of funds in an Investment Account shall be made in the name of the
Trustee (in its capacity as such), or in the name of a nominee of the Trustee.
The Trustee shall be entitled to sole possession (except with respect to
investment direction of funds held in the

                                      -70-

<PAGE>

Collection Account or any REO Account and any income and gain realized thereon)
over each such investment, and any certificate or other instrument evidencing
any such investment shall be delivered directly to the Trustee or its agent,
together with any document of transfer necessary to transfer title to such
investment to the Trustee or its nominee. In the event amounts on deposit in an
Investment Account are at any time invested in a Permitted Investment payable on
demand, the Trustee shall:

                  (x) consistent with any notice required to be given
         thereunder, demand that payment thereon be made on the last day such
         Permitted Investment may otherwise mature hereunder in an amount equal
         to the lesser of (1) all amounts then payable thereunder and (2) the
         amount required to be withdrawn on such date; and

                  (y) demand payment of all amounts due thereunder promptly upon
         determination by a Responsible Officer of the Trustee that such
         Permitted Investment would not constitute a Permitted Investment in
         respect of funds thereafter on deposit in the Investment Account.

                  (b) All income and gain realized from the investment of funds
deposited in the Collection Account and any REO Account held by or on behalf of
the Master Servicer shall be for the benefit of the Master Servicer and shall be
subject to its withdrawal in accordance with Section 3.11 or Section 3.23, as
applicable. The Master Servicer shall deposit in the Collection Account or any
REO Account, as applicable, the amount of any loss of principal incurred in
respect of any such Permitted Investment made with funds in such account
immediately upon realization of such loss.

                  (c) All income and gain realized from the investment of funds
deposited in the Distribution Account shall be for the benefit of the Trustee.
The Trustee shall deposit in the Distribution Account the amount of any loss of
principal incurred in respect of any such Permitted Investment made with funds
in such accounts immediately upon realization of such loss.

                  (d) Except as otherwise expressly provided in this Agreement,
if any default occurs in the making of a payment due under any Permitted
Investment, or if a default occurs in any other performance required under any
Permitted Investment, the Trustee may and, subject to Section 8.01 and Section
8.02(a)(v), upon the request of the NIMS Insurer or the Holders of Certificates
representing more than 50% of the Voting Rights allocated to any Class of
Certificates, shall take such action as may be appropriate to enforce such
payment or performance, including the institution and prosecution of appropriate
proceedings.

                  SECTION 3.13.             [Reserved].

                  SECTION 3.14.             Maintenance of Hazard Insurance and
                                            Errors and Omissions and Fidelity
                                            Coverage.

                  (a) The Master Servicer shall cause to be maintained for each
Mortgage Loan hazard insurance with extended coverage on the Mortgaged Property
in an amount which is at least equal to the lesser of (i) the current Principal
Balance of such Mortgage Loan and (ii) the amount necessary to fully compensate
for any damage or loss to the improvements that are a part of such property on a
replacement cost basis, in each case in an amount not less than such amount as
is necessary to avoid the application of any coinsurance clause contained in the
related hazard

                                      -71-

<PAGE>

insurance policy. The Master Servicer shall also cause to be maintained hazard
insurance with extended coverage on each REO Property in an amount which is at
least equal to the lesser of (i) the maximum insurable value of the improvements
which are a part of such property and (ii) the outstanding Principal Balance of
the related Mortgage Loan at the time it became an REO Property. The Master
Servicer will comply in the performance of this Agreement with all reasonable
rules and requirements of each insurer under any such hazard policies. Any
amounts to be collected by the Master Servicer under any such policies (other
than amounts to be applied to the restoration or repair of the property subject
to the related Mortgage or amounts to be released to the Mortgagor in accordance
with the procedures that the Master Servicer would follow in servicing loans
held for its own account, subject to the terms and conditions of the related
Mortgage and Mortgage Note) shall be deposited in the Collection Account,
subject to withdrawal pursuant to Section 3.11, if received in respect of a
Mortgage Loan, or in the REO Account, subject to withdrawal pursuant to Section
3.23, if received in respect of an REO Property. Any cost incurred by the Master
Servicer in maintaining any such insurance shall not, for the purpose of
calculating distributions to Certificateholders, be added to the unpaid
Principal Balance of the related Mortgage Loan, notwithstanding that the terms
of such Mortgage Loan so permit. It is understood and agreed that no earthquake
or other additional insurance is to be required of any Mortgagor other than
pursuant to such applicable laws and regulations as shall at any time be in
force and as shall require such additional insurance. If the Mortgaged Property
or REO Property is at any time in an area identified in the Federal Register by
the Federal Emergency Management Agency as having special flood hazards and
flood insurance has been made available, the Master Servicer will cause to be
maintained a flood insurance policy in respect thereof. Such flood insurance
shall be in an amount equal to the lesser of (i) the unpaid Principal Balance of
the related Mortgage Loan and (ii) the maximum amount of such insurance
available for the related Mortgaged Property under the national flood insurance
program (assuming that the area in which such Mortgaged Property is located is
participating in such program).

                  In the event that the Master Servicer shall obtain and
maintain a blanket policy with an insurer having a General Policy Rating of
B:III or better in Best's Key Rating Guide (or such other rating that is
comparable to such rating) insuring against hazard losses on all of the Mortgage
Loans, it shall conclusively be deemed to have satisfied its obligations as set
forth in the first two sentences of this Section 3.14, it being understood and
agreed that such policy may contain a deductible clause, in which case the
Master Servicer shall, in the event that there shall not have been maintained on
the related Mortgaged Property or REO Property a policy complying with the first
two sentences of this Section 3.14, and there shall have been one or more losses
which would have been covered by such policy, deposit to the Collection Account
from its own funds the amount not otherwise payable under the blanket policy
because of such deductible clause. In connection with its activities as
administrator and servicer of the Mortgage Loans, the Master Servicer agrees to
prepare and present, on behalf of itself, the Trustee and Certificateholders,
claims under any such blanket policy in a timely fashion in accordance with the
terms of such policy.

                  (b) The Master Servicer shall keep in force during the term of
this Agreement a policy or policies of insurance covering errors and omissions
for failure in the performance of the Master Servicer's obligations under this
Agreement, which policy or policies shall be in such form and amount that would
meet the requirements of Fannie Mae or Freddie Mac if it were the purchaser of
the Mortgage Loans, unless the Master Servicer has obtained a waiver of such
requirements from

                                      -72-

<PAGE>

Fannie Mae or Freddie Mac. The Master Servicer shall provide the Trustee and the
NIMS Insurer, upon request, with copies of such insurance policies and fidelity
bond. The Master Servicer shall also maintain a fidelity bond in the form and
amount that would meet the requirements of Fannie Mae or Freddie Mac, unless the
Master Servicer has obtained a waiver of such requirements from Fannie Mae or
Freddie Mac. The Master Servicer shall be deemed to have complied with this
provision if an Affiliate of the Master Servicer has such errors and omissions
and fidelity bond coverage and, by the terms of such insurance policy or
fidelity bond, the coverage afforded thereunder extends to the Master Servicer.
Any such errors and omissions policy and fidelity bond shall by its terms not be
cancelable without thirty days' prior written notice to the Trustee and the NIMS
Insurer. The Master Servicer shall also cause each Sub-Servicer to maintain a
policy of insurance covering errors and omissions and a fidelity bond which
would meet such requirements.

                  SECTION 3.15.             Enforcement of Due-On-Sale Clauses;
                                            Assumption Agreements.

                  The Master Servicer will, to the extent it has knowledge of
any conveyance or prospective conveyance of any Mortgaged Property by any
Mortgagor (whether by absolute conveyance or by contract of sale, and whether or
not the Mortgagor remains or is to remain liable under the Mortgage Note and/or
the Mortgage), exercise its rights to accelerate the maturity of such Mortgage
Loan under the "due-on-sale" clause, if any, applicable thereto; provided,
however, that the Master Servicer shall not be required to take such action if
in its sole business judgment the Master Servicer believes it is not in the best
interests of the Trust Fund and shall not exercise any such rights if prohibited
by law from doing so. If the Master Servicer reasonably believes it is unable
under applicable law to enforce such "due-on-sale" clause, or if any of the
other conditions set forth in the proviso to the preceding sentence apply, the
Master Servicer will enter into an assumption and modification agreement from or
with the person to whom such property has been conveyed or is proposed to be
conveyed, pursuant to which such person becomes liable under the Mortgage Note
and, to the extent permitted by applicable state law, the Mortgagor remains
liable thereon. The Master Servicer is also authorized to enter into a
substitution of liability agreement with such person, pursuant to which the
original Mortgagor is released from liability and such person is substituted as
the Mortgagor and becomes liable under the Mortgage Note, provided that no such
substitution shall be effective unless such person satisfies the underwriting
criteria of the Master Servicer and has a credit risk rating at least equal to
that of the original Mortgagor. In connection with any assumption or
substitution, the Master Servicer shall apply such underwriting standards and
follow such practices and procedures as shall be normal and usual in its general
mortgage servicing activities and as it applies to other mortgage loans owned
solely by it. The Master Servicer shall not take or enter into any assumption
and modification agreement, however, unless (to the extent practicable in the
circumstances) it shall have received confirmation, in writing, of the continued
effectiveness of any applicable hazard insurance policy. Any fee collected by
the Master Servicer in respect of an assumption, modification or substitution of
liability agreement shall be retained by the Master Servicer as additional
servicing compensation. In connection with any such assumption, no material term
of the Mortgage Note (including but not limited to the related Mortgage Rate and
the amount of the Monthly Payment) may be amended or modified, except as
otherwise required pursuant to the terms thereof. The Master Servicer shall
notify the Trustee that any such substitution, modification or assumption
agreement has been completed by forwarding to the Trustee the executed original
of such substitution, modification or assumption agreement, which document shall
be added to the

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related Mortgage File and shall, for all purposes, be considered a part of such
Mortgage File to the same extent as all other documents and instruments
constituting a part thereof.

                  Notwithstanding the foregoing paragraph or any other provision
of this Agreement, the Master Servicer shall not be deemed to be in default,
breach or any other violation of its obligations hereunder by reason of any
assumption of a Mortgage Loan by operation of law or by the terms of the
Mortgage Note or any assumption which the Master Servicer may be restricted by
law from preventing, for any reason whatever. For purposes of this Section 3.15,
the term "assumption" is deemed to also include a sale (of the Mortgaged
Property) subject to the Mortgage that is not accompanied by an assumption or
substitution of liability agreement.

                  SECTION 3.16.             Realization Upon Defaulted Mortgage
                                            Loans.

                  (a) The Master Servicer shall use its best efforts, in as
practical a time frame as possible and consistent with Servicing Standard, to
foreclose upon or otherwise comparably convert the ownership of properties
securing such of the Mortgage Loans (including, if such is the action to be
taken that results from adherence to the Loss Mitigation Procedures, selling any
such Mortgage Loans other than converting the ownership of the related
properties as provided in Section 3.16(e) below) as come into and continue in
default and as to which no satisfactory arrangements can be made for collection
of delinquent payments pursuant to Section 3.07. The Master Servicer shall be
responsible for all costs and expenses incurred by it in any such proceedings;
provided, however, that such costs and expenses will be recoverable as Servicing
Advances by the Master Servicer as contemplated in Section 3.11 and Section
3.23. The foregoing is subject to the provision that, in any case in which a
Mortgaged Property shall have suffered damage from an Uninsured Cause, the
Master Servicer shall not be required to expend its own funds toward the
restoration of such property unless it shall determine in its discretion that
such restoration will increase the proceeds of liquidation of the related
Mortgage Loan after reimbursement to itself for such expenses.

                  (b) Notwithstanding the foregoing provisions of this Section
3.16 or any other provision of this Agreement, with respect to any Mortgage Loan
as to which the Master Servicer has received actual notice of, or has actual
knowledge of, the presence of any toxic or hazardous substance on the related
Mortgaged Property, the Master Servicer shall not, on behalf of the Trustee,
either (i) obtain title to such Mortgaged Property as a result of or in lieu of
foreclosure or otherwise, or (ii) otherwise acquire possession of, or take any
other action with respect to, such Mortgaged Property, if, as a result of any
such action, the Trustee, the Trust Fund or the Certificateholders would be
considered to hold title to, to be a "mortgagee-in-possession" of, or to be an
"owner" or "operator" of such Mortgaged Property within the meaning of the
Comprehensive Environmental Response, Compensation and Liability Act of 1980, as
amended from time to time, or any comparable law, unless the Master Servicer has
also previously determined, based on its reasonable judgment and a report
prepared by a Person who regularly conducts environmental audits using customary
industry standards, that:

                  (1) such Mortgaged Property is in compliance with applicable
         environmental laws or, if not, that it would be in the best economic
         interest of the Trust Fund to take such actions as are necessary to
         bring the Mortgaged Property into compliance therewith; and

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<PAGE>

                  (2) there are no circumstances present at such Mortgaged
         Property relating to the use, management or disposal of any hazardous
         substances, hazardous materials, hazardous wastes, or petroleum-based
         materials for which investigation, testing, monitoring, containment,
         clean-up or remediation could be required under any federal, state or
         local law or regulation, or that if any such materials are present for
         which such action could be required, that it would be in the best
         economic interest of the Trust Fund to take such actions with respect
         to the affected Mortgaged Property.

                  Notwithstanding the foregoing, if such environmental audit
reveals, or if the Master Servicer has actual knowledge or notice, that such
Mortgaged Property contains such wastes or substances, the Master Servicer shall
not foreclose or accept a deed in lieu of foreclosure without the prior written
consent of the NIMS Insurer.

                  The cost of the environmental audit report contemplated by
this Section 3.16 shall be advanced by the Master Servicer, subject to the
Master Servicer's right to be reimbursed therefor from the Collection Account as
provided in Section 3.11(a)(vii), such right of reimbursement being prior to the
rights of Certificateholders to receive any amount in the Collection Account
received in respect of the affected Mortgage Loan or other Mortgage Loans.

                  If the Master Servicer determines, as described above, that it
is in the best economic interest of the Trust Fund to take such actions as are
necessary to bring any such Mortgaged Property into compliance with applicable
environmental laws, or to take such action with respect to the containment,
clean-up or remediation of hazardous substances, hazardous materials, hazardous
wastes or petroleum-based materials affecting any such Mortgaged Property, then
the Master Servicer shall take such action as it deems to be in the best
economic interest of the Trust Fund; provided that any amounts disbursed by the
Master Servicer pursuant to this Section 3.16(b) shall constitute Servicing
Advances, subject to Section 4.03(d). The cost of any such compliance,
containment, cleanup or remediation shall be advanced by the Master Servicer,
subject to the Master Servicer's right to be reimbursed therefor from the
Collection Account as provided in Section 3.11(a)(iii) and (a)(vii), such right
of reimbursement being prior to the rights of Certificateholders to receive any
amount in the Collection Account received in respect of the affected Mortgage
Loan or other Mortgage Loans.

                  (c)(i) The NIMS Insurer may, at its option, purchase a
Mortgage Loan which has become 90 or more days delinquent or for which the
Master Servicer has accepted a deed in lieu of foreclosure. Prior to purchase
pursuant to this Section 3.16(c)(i), the Master Servicer shall be required to
continue to make Advances pursuant to Section 4.03. The NIMS Insurer shall not
use any procedure in selecting Mortgage Loans to be repurchased which is
materially adverse to the interests of the Certificateholders. The NIMS Insurer
shall purchase such delinquent Mortgage Loan at a price equal to the Purchase
Price of such Mortgage Loan. Any such purchase of a Mortgage Loan pursuant to
this Section 3.16(c)(i) shall be accomplished by remittance to the Master
Servicer for deposit in the Collection Account of the amount of the Purchase
Price. The Trustee shall immediately effectuate the conveyance of such
delinquent Mortgage Loan to the NIMS Insurer to the extent necessary to vest in
the NIMS Insurer title to such Mortgage Loan, including the prompt delivery of
all documentation to the NIMS Insurer.

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<PAGE>

                  (ii) If the Master Servicer Optional Purchase Delinquency
Trigger has been met, the Master Servicer may, at its option, purchase a
Mortgage Loan which has become 90 or more days delinquent or for which the
Master Servicer has accepted a deed in lieu of foreclosure. Prior to purchase
pursuant to this Section 3.16(c)(ii), the Master Servicer shall be required to
continue to make Advances pursuant to Section 4.03. The Master Servicer shall
purchase such delinquent Mortgage Loan at a price equal to the Purchase Price of
such Mortgage Loan. Any such purchase of a Mortgage Loan pursuant to this
Section 3.16(c)(ii) shall be accomplished by deposit in the Collection Account
of the amount of the Purchase Price. The Trustee shall immediately effectuate
the conveyance of such delinquent Mortgage Loan to the Master Servicer to the
extent necessary, including the prompt delivery of all documentation to the
Master Servicer.

                  Notwithstanding the foregoing: (A) the Master Servicer shall
have the option to purchase pursuant to this Section 3.16(c)(ii) only such
delinquent Mortgage Loans having an aggregate Principal Balance such that, if
such delinquent Mortgage Loans were not in the Trust, the Master Servicer
Optional Purchase Delinquency Trigger would not be met; (B) if the Master
Servicer purchases any delinquent Mortgage Loans pursuant to this Section
3.16(c)(ii), it must purchase Mortgage Loans that are delinquent the greatest
number of days before it may purchase any that are delinquent any fewer number
of days; (C) if the Master Servicer purchases some but not all Mortgage Loans
that are delinquent any given number of days, it must purchase Mortgage Loans
having the same delinquency status in the order of lowest Principal Balance to
highest Principal Balance; (D) the Master Servicer may at any time relinquish
its rights to purchase delinquent Mortgage Loans pursuant to this Section
3.16(c)(ii) in writing delivered to the Trustee, and from and after the taking
of such action by the Master Servicer, the provisions of this Section
3.16(c)(ii) shall no longer be of any force or effect.

                  (d) Proceeds received in connection with any Final Recovery
Determination, as well as any recovery resulting from a partial collection of
Insurance Proceeds, Liquidation Proceeds or condemnation proceeds, in respect of
any Mortgage Loan, will be applied in the following order of priority: first, to
unpaid Servicing Fees; second, to reimburse the Master Servicer or any Sub-
Servicer for any related unreimbursed Servicing Advances pursuant to Section
3.11(a)(iii) and Advances pursuant to Section 3.11(a)(ii); third, to accrued and
unpaid interest on the Mortgage Loan, to the date of the Final Recovery
Determination, or to the Due Date prior to the Distribution Date on which such
amounts are to be distributed if not in connection with a Final Recovery
Determination; and fourth, as a recovery of principal of the Mortgage Loan. The
portion of the recovery so allocated to unpaid Servicing Fees shall be
reimbursed to the Master Servicer or any Sub-Servicer pursuant to Section
3.11(a)(iii).

                  SECTION 3.17.             Trustee to Cooperate; Release of
                                            Mortgage Files.

                  (a) Upon the payment in full of any Mortgage Loan, or the
receipt by the Master Servicer of a notification that payment in full shall be
escrowed in a manner customary for such purposes, the Master Servicer shall
deliver to the Trustee, in written (with two executed copies) or electronic
format, a Request for Release in the form of Exhibit E (which certification
shall include a statement to the effect that all amounts received or to be
received in connection with such payment which are required to be deposited in
the Collection Account pursuant to Section 3.10 have been or will be so
deposited) signed by a Servicing Officer (or in a mutually agreeable electronic
format that

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will, in lieu of a signature on its face, originate from a Servicing Officer)
and shall request delivery to it of the Mortgage File. Upon receipt of such
certification and request, the Trustee shall, within three Business Days,
release and send by overnight mail, at the expense of the Master Servicer, the
related Mortgage File to the Master Servicer. The Trustee agrees to indemnify
the Master Servicer, out of its own funds, for any loss, liability or expense
(other than special, indirect, punitive or consequential damages which will not
be paid by the Trustee) incurred by the Master Servicer as a proximate result of
the Trustee's breach of its obligations pursuant to this Section 3.17. No
expenses incurred in connection with any instrument of satisfaction or deed of
reconveyance shall be chargeable to the Collection Account or the Distribution
Account.

                  (b) From time to time and as appropriate for the servicing or
foreclosure of any Mortgage Loan, including, for this purpose, collection under
any insurance policy relating to the Mortgage Loans, the Trustee shall, upon any
request made by or on behalf of the Master Servicer and delivery to the Trustee,
in written (with two executed copies) or electronic format, of a Request for
Release in the form of Exhibit E signed by a Servicing Officer (or in a mutually
agreeable electronic format that will, in lieu of a signature on its face,
originate from a Servicing Officer), release the related Mortgage File to the
Master Servicer within three Business Days, and the Trustee shall, at the
direction of the Master Servicer, execute such documents as shall be necessary
to the prosecution of any such proceedings. Such Request for Release shall
obligate the Master Servicer to return each and every document previously
requested from the Mortgage File to the Trustee when the need therefor by the
Master Servicer no longer exists, unless the Mortgage Loan has been liquidated
and the Liquidation Proceeds relating to the Mortgage Loan have been deposited
in the Collection Account or the Mortgage 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, and the Master Servicer has delivered, or caused to be
delivered, to the Trustee an additional Request for Release certifying as to
such liquidation or action or proceedings. Upon the request of the Trustee, the
Master Servicer shall provide notice to the Trustee of the name and address of
the Person to which such Mortgage File or such document was delivered and the
purpose or purposes of such delivery. Upon receipt of a Request for Release, in
written (with two executed copies) or electronic format, from a Servicing
Officer stating that such Mortgage Loan was liquidated and that all amounts
received or to be received in connection with such liquidation that are required
to be deposited into the Collection Account have been so deposited, or that such
Mortgage Loan has become an REO Property, such Mortgage Loan shall be released
by the Trustee to the Master Servicer or its designee.

                  (c) Upon written certification of a Servicing Officer, the
Trustee shall execute and deliver to the Master Servicer or the Sub-Servicer, as
the case may be, copies of, any 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

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<PAGE>

the Mortgage, except for the termination of such a lien upon completion of the
foreclosure or trustee's sale.

                  SECTION 3.18.             Servicing Compensation.

                  As compensation for the activities of the Master Servicer
hereunder, the Master Servicer shall be entitled to the Servicing Fee with
respect to each Mortgage Loan payable solely from payments of interest in
respect of such Mortgage Loan, subject to Section 3.24. In addition, the Master
Servicer shall be entitled to recover unpaid Servicing Fees out of Insurance
Proceeds, Liquidation Proceeds or condemnation proceeds to the extent permitted
by Section 3.11(a)(iii) and out of amounts derived from the operation and sale
of an REO Property to the extent permitted by Section 3.23. Except as provided
in Section 3.29, the right to receive the Servicing Fee may not be transferred
in whole or in part except in connection with the transfer of all of the Master
Servicer's responsibilities and obligations under this Agreement; provided,
however, that the Master Servicer may pay from the Servicing Fee any amounts due
to a Sub-Servicer pursuant to a Sub-Servicing Agreement entered into under
Section 3.02.

                  Additional servicing compensation in the form of assumption
fees, late payment charges, insufficient funds charges, ancillary income or
otherwise (other than Prepayment Charges) shall be retained by the Master
Servicer only to the extent such fees or charges are received by the Master
Servicer. The Master Servicer shall also be entitled pursuant to Section
3.11(a)(iv) to withdraw from the Collection Account and pursuant to Section
3.23(b) to withdraw from any REO Account, as additional servicing compensation,
interest or other income earned on deposits therein, subject to Section 3.12 and
Section 3.24. The Master Servicer shall be required to pay all expenses incurred
by it in connection with its servicing activities hereunder (including premiums
for the insurance required by Section 3.14, to the extent such premiums are not
paid by the related Mortgagors or by a Sub-Servicer and servicing compensation
of each Sub-Servicer) and shall not be entitled to reimbursement therefor except
as specifically provided herein.

                  The Master Servicer shall be entitled to any Prepayment
Interest Excess, which it may withdraw from the Collection Account pursuant to
Section 3.11(a)(ix).

                  SECTION 3.19.             Reports to the Trustee; Collection
                                            Account Statements.

                  Not later than twenty days after each Distribution Date, the
Master Servicer shall forward to the Trustee, the NIMS Insurer and the Depositor
the most current available bank statement for the Collection Account. Copies of
such statement shall be provided by the Trustee to any Certificateholder and to
any Person identified to the Trustee as a prospective transferee of a
Certificate, upon request at the expense of the requesting party, provided such
statement is delivered by the Master Servicer to the Trustee.

                  SECTION 3.20.             Statement as to Compliance.

                  The Master Servicer will deliver to the Trustee, the NIMS
Insurer and the Depositor not later than February 28th of each calendar year,
commencing in 2004, an Officers' Certificate stating, as to each signatory
thereof, that (i) a review of the activities of the Master Servicer during

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the preceding year and of performance under this Agreement has been made under
such officers' supervision and (ii) to the best of such officers' knowledge,
based on such review, the Master Servicer has fulfilled all of its obligations
under this Agreement throughout such year, or, if there has been a default in
the fulfillment of any such obligation, specifying each such default known to
such officer and the nature and status thereof. Copies of any such statement
shall be provided by the Trustee to any Certificateholder and to any Person
identified to the Trustee as a prospective transferee of a Certificate, upon
request at the expense of the requesting party, provided such statement is
delivered by the Master Servicer to the Trustee.

                  SECTION 3.21.             Independent Public Accountants'
                                            Servicing Report.

                  Not later than February 28th of each calendar year, commencing
in 2004, the Master Servicer, at its expense, shall cause a nationally
recognized firm of independent certified public accountants to furnish to the
Master Servicer a report stating that (i) it has obtained a letter of
representation regarding certain matters from the management of the Master
Servicer which includes an assertion that the Master Servicer has complied with
certain minimum residential mortgage loan servicing standards, identified in the
Uniform Single Attestation Program for Mortgage Bankers established by the
Mortgage Bankers Association of America, with respect to the servicing of
residential mortgage loans during the most recently completed fiscal year and
(ii) on the basis of an examination conducted by such firm in accordance with
standards established by the American Institute of Certified Public Accountants,
such representation is fairly stated in all material respects, subject to such
exceptions and other qualifications that may be appropriate. In rendering its
report such firm may rely, as to matters relating to the direct servicing of
residential mortgage loans by Sub- Servicers, upon comparable reports of firms
of independent certified public accountants rendered on the basis of
examinations conducted in accordance with the same standards (rendered within
one year of such report) with respect to those Sub-Servicers. Immediately upon
receipt of such report, the Master Servicer shall furnish a copy of such report
to the Trustee, the NIMS Insurer and each Rating Agency. Copies of such
statement shall be provided by the Trustee to any Certificateholder upon request
at the Master Servicer's expense, provided that such statement is delivered by
the Master Servicer to the Trustee.

                  SECTION 3.22.             Access to Certain Documentation.

                  The Master Servicer shall provide to the Office of Thrift
Supervision, the FDIC, and any other federal or state banking or insurance
regulatory authority that may exercise authority over any Certificateholder,
access to the documentation regarding the Mortgage Loans required by applicable
laws and regulations. Such access shall be afforded without charge, but only
upon reasonable request and during normal business hours at the offices of the
Master Servicer designated by it. In addition, access to the documentation
regarding the Mortgage Loans will be provided to any Certificateholder, the
Trustee, the NIMS Insurer and to any Person identified to the Master Servicer as
a prospective transferee of a Certificate, upon reasonable request during normal
business hours at the offices of the Master Servicer designated by it at the
expense of the Person requesting such access.

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                  SECTION 3.23.             Title, Management and Disposition of
                                            REO Property.

                  (a) The deed or certificate of sale of any REO Property shall
be taken in the name of the Trustee, or its nominee, in trust for the benefit of
the Certificateholders. The Master Servicer, on behalf of REMIC I, shall sell
any REO Property as soon as practical and in any event no later than the end of
the third full taxable year after the taxable year in which such REMIC acquires
ownership of such REO Property for purposes of Section 860G(a)(8) of the Code or
request from the Internal Revenue Service, no later than 60 days before the day
on which the three-year grace period would otherwise expire, an extension of
such three-year period, unless the Master Servicer shall have delivered to the
Trustee and the NIMS Insurer an Opinion of Counsel acceptable to the NIMS
Insurer and addressed to the Trustee, the NIMS Insurer and the Depositor, to the
effect that the holding by the REMIC of such REO Property subsequent to three
years after its acquisition will not result in the imposition on the REMIC of
taxes on "prohibited transactions" thereof, as defined in Section 860F of the
Code, or cause any of the REMICs created hereunder to fail to qualify as a REMIC
under Federal law at any time that any Certificates are outstanding. The Master
Servicer shall manage, conserve, protect and operate each REO Property for the
Certificateholders solely for the purpose of its prompt disposition and sale in
a manner which does not cause such REO Property to fail to qualify as
"foreclosure property" within the meaning of Section 860G(a)(8) of the Code or
result in the receipt by any of the REMICs created hereunder of any "income from
non-permitted assets" within the meaning of Section 860F(a)(2)(B) of the Code,
or any "net income from foreclosure property" which is subject to taxation under
the REMIC Provisions.

                  (b) The Master Servicer shall separately account for all funds
collected and received in connection with the operation of any REO Property and
shall establish and maintain, or cause to be established and maintained, with
respect to REO Properties an account held in trust for the Trustee for the
benefit of the Certificateholders (the "REO Account"), which shall be an
Eligible Account. The Master Servicer shall be permitted to allow the Collection
Account to serve as the REO Account, subject to separate ledgers for each REO
Property. The Master Servicer shall be entitled to retain or withdraw any
interest income paid on funds deposited in the REO Account.

                  (c) The Master Servicer shall have full power and authority,
subject only to the specific requirements and prohibitions of this Agreement, to
do any and all things in connection with any REO Property as are consistent with
the manner in which the Master Servicer manages and operates similar property
owned by the Master Servicer or any of its Affiliates, all on such terms and for
such period (subject to the requirement of prompt disposition set forth in
Section 3.23(a)) as the Master Servicer deems to be in the best interests of
Certificateholders. In connection therewith, the Master Servicer shall deposit,
or cause to be deposited in the clearing account in which it customarily
deposits payments and collections on mortgage loans in connection with its
mortgage loan servicing activities on a daily basis, and in no event more than
one Business Day after the Master Servicer's receipt thereof, and shall
thereafter deposit in the REO Account, in no event more than two Business Days
after the Master Servicer's receipt thereof, all revenues received by it with
respect to an REO Property and shall withdraw therefrom funds necessary for the
proper operation, management and maintenance of such REO Property including,
without limitation:

                  (i) all insurance premiums due and payable in respect of such
         REO Property;

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<PAGE>

                  (ii) all real estate taxes and assessments in respect of such
         REO Property that may result in the imposition of a lien thereon; and

                  (iii) all costs and expenses necessary to maintain such REO
         Property.

                  To the extent that amounts on deposit in the REO Account with
respect to an REO Property are insufficient for the purposes set forth in
clauses (i) through (iii) above with respect to such REO Property, the Master
Servicer shall advance from its own funds such amount as is necessary for such
purposes if, but only if, the Master Servicer would make such advances if the
Master Servicer owned the REO Property and if in the Master Servicer's judgment,
the payment of such amounts will be recoverable from the rental or sale of the
REO Property.

                  Notwithstanding the foregoing, neither the Master Servicer nor
the Trustee shall:

                  (A) authorize the Trust Fund to enter into, renew or extend
         any New Lease with respect to any REO Property, if the New Lease by its
         terms will give rise to any income that does not constitute Rents from
         Real Property;

                  (B) authorize any amount to be received or accrued under any
         New Lease other than amounts that will constitute Rents from Real
         Property;

                  (C) authorize any construction on any REO Property, other than
         the completion of a building or other improvement thereon, and then
         only if more than ten percent of the construction of such building or
         other improvement was completed before default on the related Mortgage
         Loan became imminent, all within the meaning of Section 856(e)(4)(B) of
         the Code; or

                  (D) authorize any Person to Directly Operate any REO Property
         on any date more than 90 days after its date of acquisition by the
         Trust Fund;

unless, in any such case, the Master Servicer has obtained an Opinion of
Counsel, provided to the Trustee and the NIMS Insurer, to the effect that such
action will not cause such REO Property to fail to qualify as "foreclosure
property" within the meaning of Section 860G(a)(8) of the Code at any time that
it is held by the REMIC, in which case the Master Servicer may take such actions
as are specified in such Opinion of Counsel.

                  The Master Servicer may contract with any Independent
Contractor for the operation and management of any REO Property, provided that:

                  (1) the terms and conditions of any such contract shall not be
         inconsistent herewith;

                  (2) any such contract shall require, or shall be administered
         to require, that the Independent Contractor pay all costs and expenses
         incurred in connection with the operation and management of such REO
         Property, including those listed above and remit all related revenues
         (net of such costs and expenses) to the Master Servicer as soon as
         practicable, but

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<PAGE>

         in no event later than thirty days following the receipt thereof by
         such Independent Contractor;

                  (3) none of the provisions of this Section 3.23(c) relating to
         any such contract or to actions taken through any such Independent
         Contractor shall be deemed to relieve the Master Servicer of any of its
         duties and obligations to the Trustee on behalf of the
         Certificateholders with respect to the operation and management of any
         such REO Property; and

                  (4) the Master Servicer shall be obligated with respect
         thereto to the same extent as if it alone were performing all duties
         and obligations in connection with the operation and management of such
         REO Property.

                  The Master Servicer shall be entitled to enter into any
agreement with any Independent Contractor performing services for it related to
its duties and obligations hereunder for indemnification of the Master Servicer
by such Independent Contractor, and nothing in this Agreement shall be deemed to
limit or modify such indemnification. The Master Servicer shall be solely liable
for all fees owed by it to any such Independent Contractor, irrespective of
whether the Master Servicer's compensation pursuant to Section 3.18 is
sufficient to pay such fees; provided, however, that to the extent that any
payments made by such Independent Contractor would constitute Servicing Advances
if made by the Master Servicer, such amounts shall be reimbursable as Servicing
Advances made by the Master Servicer.

                  (d) In addition to the withdrawals permitted under Section
3.23(c), the Master Servicer may from time to time make withdrawals from the REO
Account for any REO Property: (i) to pay itself or any Sub-Servicer unpaid
Servicing Fees in respect of the related Mortgage Loan; and (ii) to reimburse
itself or any Sub-Servicer for unreimbursed Servicing Advances and Advances made
in respect of such REO Property or the related Mortgage Loan. On the Master
Servicer Remittance Date, the Master Servicer shall withdraw from each REO
Account maintained by it and deposit into the Distribution Account in accordance
with Section 3.10(d)(ii), for distribution on the related Distribution Date in
accordance with Section 4.01, the income from the related REO Property received
during the prior calendar month, net of any withdrawals made pursuant to Section
3.23(c) or this Section 3.23(d).

                  (e) Subject to the time constraints set forth in Section
3.23(a), each REO Disposition shall be carried out by the Master Servicer in a
manner, at such price and upon such terms and conditions as shall be in
conformity with the requirements of the Loss Mitigation Procedures and as shall
be normal and usual in its Servicing Standard.

                  (f) The proceeds from the REO Disposition, net of any amount
required by law to be remitted to the Mortgagor under the related Mortgage Loan
and net of any payment or reimbursement to the Master Servicer or any
Sub-Servicer as provided above, shall be deposited in the Distribution Account
in accordance with Section 3.10(d)(ii) on the Master Servicer Remittance Date in
the month following the receipt thereof for distribution on the related
Distribution Date in accordance with Section 4.01. Any REO Disposition shall be
for cash only (unless changes in the REMIC Provisions made subsequent to the
Startup Day allow a sale for other consideration).

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                  (g) The Master Servicer shall file information returns with
respect to the receipt of mortgage interest received in a trade or business,
reports of foreclosures and abandonments of any Mortgaged Property and
cancellation of indebtedness income with respect to any Mortgaged Property as
required by Sections 6050H, 6050J and 6050P of the Code, respectively. Such
reports shall be in form and substance sufficient to meet the reporting
requirements imposed by such Sections 6050H, 6050J and 6050P of the Code.

                  SECTION 3.24.             Obligations of the Master Servicer
                                            in Respect of Prepayment Interest
                                            Shortfalls.

                  Not later than 1:00 p.m. New York time on each Master Servicer
Remittance Date, the Master Servicer shall remit to the Distribution Account an
amount ("Compensating Interest") equal to the lesser of (A) the aggregate of the
Prepayment Interest Shortfalls for the related Distribution Date and (B) its
aggregate Servicing Fee received in the related Due Period, any interest or
investment income earned on funds deposited in the Collection Account and any
Prepayment Interest Excess earned during the related Prepayment Period. The
Master Servicer shall not have the right to reimbursement for any amounts
remitted to the Trustee in respect of Compensating Interest. Such amounts so
remitted shall be included in the Available Funds and distributed therewith on
the next Distribution Date. The Master Servicer shall not be obligated to pay
Compensating Interest with respect to Relief Act Interest Shortfalls.

                  SECTION 3.25.             [Reserved]

                  SECTION 3.26.             Obligations of the Master Servicer
                                            in Respect of Mortgage Rates and
                                            Monthly Payments.

                  In the event that a shortfall in any collection on or
liability with respect to the Mortgage Loans in the aggregate results from or is
attributable to adjustments to Mortgage Rates, Monthly Payments or Stated
Principal Balances that were made by the Master Servicer in a manner not
consistent with the terms of the related Mortgage Note and this Agreement, the
Master Servicer, upon discovery or receipt of notice thereof, immediately shall
deposit in the Collection Account from its own funds the amount of any such
shortfall and shall indemnify and hold harmless the Trust Fund, the Trustee, the
Depositor and any successor servicer in respect of any such liability. Such
indemnities shall survive the termination or discharge of this Agreement.
Notwithstanding the foregoing, this Section 3.26 shall not limit the ability of
the Master Servicer to seek recovery of any such amounts from the related
Mortgagor under the terms of the related Mortgage Note, as permitted by law.

                  SECTION 3.27.             Solicitations.

                  From and after the Closing Date, the Master Servicer agrees
that it will not take any action or permit or cause any action to be taken by
any of its agents and Affiliates, or by any independent contractors or
independent mortgage brokerage companies on the Master Servicer's behalf, to
personally, by telephone, mail or electronic mail, solicit the Mortgagor under
any Mortgage Loan for the purpose of refinancing such Mortgage Loan; provided,
that the Master Servicer may solicit any Mortgagor for whom the Master Servicer
has received a request for

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verification of mortgage, a request for demand for payoff, a mortgagor initiated
written or verbal communication indicating a desire to prepay the related
Mortgage Loan, another mortgage company has pulled a credit report on the
mortgagor or the mortgagor initiates a title search; provided further, it is
understood and agreed that promotions undertaken by the Master Servicer or any
of its Affiliates which (i) concern optional insurance products or other
additional products or (ii) are directed to the general public at large,
including, without limitation, mass mailings based on commercially acquired
mailing lists, newspaper, radio and television advertisements shall not
constitute solicitation under this Section, nor is the Master Servicer
prohibited from responding to unsolicited requests or inquiries made by a
Mortgagor or an agent of a Mortgagor. Furthermore, the Master Servicer shall be
permitted to include in its monthly statements to borrowers or otherwise,
statements regarding the availability of the Master Servicer's counseling
services with respect to refinancing mortgage loans.

                  SECTION 3.28.             Net WAC Rate Carryover Reserve
                                            Account.

                  No later than the Closing Date, the Trustee shall establish
and maintain with itself a separate, segregated trust account titled, "Net WAC
Rate Carryover Reserve Account, Wells Fargo Bank Minnesota, National
Association, as Trustee, in trust for the registered holders of MASTR Asset
Backed Securities Trust 2003-OPT1, Mortgage Pass-Through Certificates." On the
Closing Date, the Depositor will deposit, or cause to be deposited, into the Net
WAC Rate Carryover Reserve Account $1,000. In addition, the amount deposited in
the Net WAC Rate Carryover Reserve Account shall be increased by any payments
received by the Trustee under the Cap Contract and deposited into the Net WAC
Rate Carryover Reserve Account for the benefit of the Class A-2 Certificates and
the Mezzanine Certificates (other than the Class MF-5 Certificates).

                  On each Distribution Date as to which there is a Net WAC Rate
Carryover Amount payable to the Class A Certificates and/or the Mezzanine
Certificates, the Trustee has been directed by the Class CE Certificateholders
to, and therefore will, deposit into the Net WAC Rate Carryover Reserve Account
the amounts described in Section 4.01(a)(4)(xv), rather than distributing such
amounts to the Class CE Certificateholders. On each such Distribution Date, the
Trustee shall hold all such amounts for the benefit of the Holders of the Class
A Certificates and the Mezzanine Certificates, and will distribute such amounts
to the Holders of the Class A Certificates and/or the Mezzanine Certificates in
the amounts and priorities set forth in Section 4.01(d). If no Net WAC Rate
Carryover Amounts are payable on a Distribution Date, the Trustee shall deposit
into the Net WAC Rate Carryover Reserve Account on behalf of the Class CE
Certificateholders, from amounts otherwise distributable to the Class CE
Certificateholders, an amount such that when added to other amounts already on
deposit in the Net WAC Rate Carryover Reserve Account, the aggregate amount on
deposit therein is equal to $1,000.

                  For federal and state income tax purposes, the Class CE
Certificateholders will be deemed to be the owners of the Net WAC Rate Carryover
Reserve Account and all amounts deposited into the Net WAC Rate Carryover
Reserve Account (other than the initial deposit therein of $1,000) shall be
treated as amounts distributed by REMIC II to the Holders of the Class CE
Certificates. Upon the termination of the Trust Fund, or the payment in full of
the Class A Certificates and the Mezzanine Certificates, all amounts remaining
on deposit in the Net WAC Rate Carryover Reserve Account will be released by the
Trust Fund and distributed to the Class CE

                                      -84-

<PAGE>

Certificateholders or their designees. The Net WAC Rate Carryover Reserve
Account will be part of the Trust Fund but not part of any REMIC and any
payments to the Holders of the Class A Certificates or the Mezzanine
Certificates of Net WAC Rate Carryover Amounts will not be payments with respect
to a "regular interest" in a REMIC within the meaning of Code Section
860(G)(a)(1).

                  By accepting a Class CE Certificate, each Class CE
Certificateholder hereby agrees to direct the Trustee, and the Trustee hereby is
directed, to deposit into the Net WAC Rate Carryover Reserve Account the amounts
described above on each Distribution Date as to which there is any Net WAC Rate
Carryover Amount rather than distributing such amounts to the Class CE
Certificateholders. By accepting a Class CE Certificate, each Class CE
Certificateholder further agrees that such direction is given for good and
valuable consideration, the receipt and sufficiency of which is acknowledged by
such acceptance.

                  At the direction of the Holders of a majority in Percentage
Interest in the Class CE Certificates, the Trustee shall direct any depository
institution maintaining the Net WAC Rate Carryover Reserve Account to invest the
funds in such account in one or more Permitted Investments bearing interest or
sold at a discount, and maturing, unless payable on demand, (i) no later than
the Business Day immediately preceding the date on which such funds are required
to be withdrawn from such account pursuant to this Agreement, if a Person other
than the Trustee or an Affiliate manages or advises such investment, and (ii) no
later than the date on which such funds are required to be withdrawn from such
account pursuant to this Agreement, if the Trustee or an Affiliate manages or
advises such investment. If no investment direction of the Holders of a majority
in Percentage Interest in the Class CE Certificates with respect to the Net WAC
Rate Carryover Reserve Account is received by the Trustee, the Trustee shall
invest the funds in such account in Permitted Investments managed by the Trustee
or an Affiliate of the kind described in clause (vi) of the definition of
Permitted Investments. All income and gain earned upon such investment shall be
deposited into the Net WAC Rate Carryover Reserve Account.

                  For federal tax return and information reporting, the right of
the Class A Certificateholders and the Mezzanine Certificateholders to receive
payments from the Net WAC Rate Carryover Reserve Account in respect of any Net
Wac Rate Carryover Amount shall be assigned a value of zero.

                  SECTION 3.29.             Advance Facility.

                  (a) The Master Servicer and/or the Trustee on behalf of the
Trust Fund, in either case, with the consent of the NIMS Insurer and the Master
Servicer in the case of the Trustee, is hereby authorized to enter into a
facility with any Person which provides that such Person (an "Advancing Person")
may fund Advances and/or Servicing Advances to the Trust Fund under this
Agreement, although no such facility shall reduce or otherwise affect the Master
Servicer's obligation to fund such Advances and/or Servicing Advances. If the
Master Servicer enters into such an Advance Facility pursuant to this Section
3.29, upon reasonable request of the Advancing Person, the Trustee shall execute
a letter of acknowledgment, confirming its receipt of notice of the existence of
such Advance Facility. To the extent that an Advancing Person funds any Advance
or any Servicing Advance and provides the Trustee with notice acknowledged by
the Servicer that such

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<PAGE>

Advancing Person is entitled to reimbursement, such Advancing Person shall be
entitled to receive reimbursement pursuant to this Agreement for such amount to
the extent provided in Section 3.29(b). Such notice from the Advancing Person
must specify the amount of the reimbursement, the Section of this Agreement that
permits the applicable Advance or Servicing Advance to be reimbursed and the
section(s) of the Advance Facility that entitle the Advancing Person to request
reimbursement from the Trustee, rather than the Master Servicer, and include the
Master Servicer's acknowledgment thereto or proof of an Event of Default under
the Advance Facility. The Trustee shall have no duty or liability with respect
to any calculation of any reimbursement to be paid to an Advancing Person and
shall be entitled to rely without independent investigation on the Advancing
Person's notice provided pursuant to this Section 3.29. An Advancing Person
whose obligations hereunder are limited to the funding of Advances and/or
Servicing Advances shall not be required to meet the qualifications of a Master
Servicer or a Sub-Servicer pursuant to Section 6.06 hereof and will not be
deemed to be a Sub-Servicer under this Agreement. If the terms of a facility
proposed to be entered into with an Advancing Person by the Trust Fund would not
materially and adversely affect the interests of any Certificateholder, then the
NIMS Insurer shall not withhold its consent to the Trust Fund's entering such
facility.

                  (b) If an advancing facility is entered into, then the Master
Servicer shall not be permitted to reimburse itself therefor under Section
3.11a(ii), Section 3.11a(iii), Section 3.11a(v), Section 3.11a(vi) Section
3.11a(vii) and Section 4.04(b) prior to the remittance to the Trust Fund, but
instead the Master Servicer shall include such amounts in the applicable
remittance to the Trustee made pursuant to Section 3.10(a). The Trustee is
hereby authorized to pay to the Advancing Person, reimbursements for Advances
and Servicing Advances from the Distribution Account to the same extent the
Master Servicer would have been permitted to reimburse itself for such Advances
and/or Servicing Advances in accordance with Section 3.11a(ii), Section
3.11a(iii), Section 3.11a(v), Section 3.11a(vi), Section 3.11a(vii) or Section
4.04(b), as the case may be, had the Master Servicer itself funded such Advance
or Servicing Advance. The Trustee is hereby authorized to pay directly to the
Advancing Person such portion of the Servicing Fee as the parties to any
advancing facility agree.

                  (c) All Advances and Servicing Advances made pursuant to the
terms of this Agreement shall be deemed made and shall be reimbursed on a "first
in-first out" (FIFO) basis.

                  (d) Any amendment to this Section 3.29 or to any other
provision of this Agreement that may be necessary or appropriate to effect the
terms of an Advance Facility as described generally in this Section 3.29,
including amendments to add provisions relating to a successor master servicer,
may be entered into by the Trustee and the Master Servicer without the consent
of any Certificateholder but with the consent of the NIMS Insurer,
notwithstanding anything to the contrary in this Agreement.

                  SECTION 3.30.             PMI Policy; Claims Under the PMI
                                            Policy.

                  Notwithstanding anything to the contrary elsewhere in this
Article III, the Master Servicer shall not agree to any modification or
assumption of a PMI Mortgage Loan or take any other action with respect to a PMI
Mortgage Loan that could result in denial of coverage under the PMI Policy. The
Master Servicer shall notify the PMI Insurer that the Trustee, on behalf of the

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<PAGE>

Certificateholders, is the Insured, as that term is defined in the PMI Policy,
of each PMI Mortgage Loan. The Master Servicer shall, on behalf of the Trustee,
prepare and file on a timely basis with the PMI Insurer, with a copy to the
Trustee, all claims which may be made under the PMI Policy with respect to the
PMI Mortgage Loans. Consistent with all rights and obligations hereunder, the
Master Servicer shall take all actions required under the PMI Policy as a
condition to the payment of any such claim. Any amount received from the PMI
Insurer with respect to any such PMI Mortgage Loan shall be deposited by the
Master Servicer, no later than two Business Days following receipt thereof, into
the Collection Account.

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<PAGE>

                                   ARTICLE IV

                         PAYMENTS TO CERTIFICATEHOLDERS

                  SECTION 4.01.             Distributions.

                  (a)(1) On each Distribution Date, the following amounts, in
the following order of priority, shall be distributed by REMIC I to REMIC II on
account of the REMIC I Regular Interests or withdrawn from the Distribution
Account and distributed to the holders of the Class R Certificates (in respect
of the Class R-I Interest), as the case may be:

                  (i) (a) to Holders of REMIC I Regular Interest I-LTAA, REMIC I
         Regular Interest I-LTA1, REMIC I Regular Interest I-LTA2, REMIC I
         Regular Interest I-LTM1, REMIC I Regular Interest I-LTM2, REMIC I
         Regular Interest I-LTM3, REMIC I Regular Interest I-LTM4, REMIC I
         Regular Interest I-LTMV5, REMIC I Regular Interest I-LTMF5, REMIC I
         Regular Interest I-LTZZ and REMIC I Regular Interest I-LTP, PRO RATA,
         in an amount equal to (A) the Uncertificated Interest for such
         Distribution Date, plus (B) any amounts in respect thereof remaining
         unpaid from previous Distribution Dates. Amounts payable as
         Uncertificated Interest in respect of REMIC I Regular Interest I-LTZZ
         shall be reduced and deferred when the REMIC I Overcollateralized
         Amount is less than the REMIC I Required Overcollateralization Amount,
         by the lesser of (x) the amount of such difference and (y) the Maximum
         I-LTZZ Uncertificated Interest Deferral Amount and such amount will be
         payable to the Holders of REMIC I Regular Interest I-LTA1, REMIC I
         Regular Interest I-LTA2, REMIC I Regular Interest I-LTM1, REMIC I
         Regular Interest I-LTM2, REMIC I Regular Interest I-LTM3, REMIC Regular
         Interest I-LTM4, REMIC Regular Interest I- LTM5V and REMIC I Regular
         Interest I-LTMF5 in the same proportion as the Overcollateralization
         Deficiency Amount is allocated to the Corresponding Certificates; and

                           (b) to Holders of REMIC I Regular Interest I-LT1SUB,
         REMIC I Regular Interest I-LT1GRP, REMIC I Regular Interest I-LT2SUB,
         REMIC I Regular Interest I- LT2GRP and REMIC I Regular Interest I-LTXX,
         PRO RATA, in an amount equal to (A) the Uncertificated Interest for
         such Distribution Date, plus (B) any amounts in respect thereof
         remaining unpaid from previous Distribution Dates;

                  (ii) second, to the Holders of REMIC I Regular Interests, in
         an amount equal to the remainder of the REMIC I Marker Allocation
         Percentage of Available Funds for such Distribution Date after the
         distributions made pursuant to clause (i) above, allocated as follows:

                           (a) to the Holders of REMIC I Regular Interest I-LTAA
         and REMIC I Regular Interest I-LTP, 98.00% of such remainder (other
         than amounts payable under clause (d) below), until the Uncertificated
         Balance of such REMIC I Regular Interest is reduced to zero, provided,
         however, that REMIC I Regular Interest I-LTP shall not be reduced until
         the Distribution Date immediately following the expiration of the
         latest Prepayment Charge as identified on the Prepayment Charge
         Schedule or any Distribution Date thereafter, at which

                                      -88-

<PAGE>

         point such amount shall be distributed to REMIC I Regular Interest
         I-LTP, until $100 has been distributed pursuant to this clause;

                           (b) to the Holders of REMIC I Regular Interest
         I-LTA1, REMIC I Regular Interest I-LTA2, REMIC I Regular Interest
         I-LTM1, REMIC I Regular Interest I-LTM2, REMIC I Regular Interest
         I-LTM3, REMIC I Regular Interest I-LTM4, REMIC Regular Interest I-LTMV5
         and REMIC I Regular Interest I-LTMF5, 1.00% of such remainder (other
         than amounts payable under clause (d) below), in the same proportion as
         principal payments are allocated to the Corresponding Certificates,
         until the Uncertificated Balances of such REMIC I Regular Interests are
         reduced to zero;

                           (c) to the Holders of REMIC I Regular Interest
         I-LTZZ, 1.00% of such remainder (other than amounts payable under
         clause (d) below), until the Uncertificated Balance of such REMIC I
         Regular Interest is reduced to zero; then

                           (d) any remaining amount to the Holders of the Class
         R Certificates (in respect of the Class R-I Interest);

         provided, however, that (i) 98.00% and (ii) 2.00% of any principal
         payments that are attributable to an Overcollateralization Release
         Amount shall be allocated to Holders of (i) REMIC I Regular Interest
         I-LTAA and REMIC I Regular Interest I-LTP, in that order and (ii) REMIC
         I Regular Interest I-LTZZ, respectively; provided that REMIC I Regular
         Interest I-LTP shall not be reduced until the Distribution Date
         immediately following the expiration of the latest Prepayment Charge as
         identified on the Prepayment Charge Schedule or any Distribution Date
         thereafter, at which point such amount shall be distributed to REMIC I
         Regular Interest I-LTP, until $100 has been distributed pursuant to
         this clause.

                  On each Distribution Date, all amounts representing Prepayment
         Charges in respect of the Mortgage Loans received during the related
         Prepayment Period and any Master Servicer Prepayment Charge Payment
         Amount paid by the Master Servicer during the related Prepayment Period
         will be distributed by REMIC I to the Holders of REMIC I Regular
         Interest I-LTP. The payment of the foregoing amounts to the Holders of
         REMIC I Regular Interest I-LTP shall not reduce the Uncertificated
         Balance thereof.

                  (iii) to the Holders of REMIC I Regular Interests, in an
         amount equal to the remainder of the REMIC I Sub WAC Allocation
         Percentage of Available Funds for such Distribution Date after the
         distributions made pursuant to clause (i) above, allocated so that:

                           distributions of principal shall be deemed to be made
         to the REMIC I Regular Interests first, so as to keep the
         Uncertificated Balance of each REMIC I Regular Interest ending with the
         designation "GRP" equal to 0.01% of the aggregate Stated Principal
         Balance of the Mortgage Loans in the related Loan Group; second, to
         each REMIC I Regular Interest ending with the designation "SUB," so
         that the Uncertificated Balance of each such REMIC I Regular Interest
         is equal to 0.01% of the excess of (x) the aggregate Stated Principal
         Balance of the Mortgage Loans in the related Loan Group over (y) the
         Certificate Principal Balance of the Class A Certificate in the related
         Loan Group (except that if any such excess

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<PAGE>

         is a larger number than in the preceding distribution period, the least
         amount of principal shall be distributed to such REMIC I Regular
         Interests such that the REMIC I Subordinated Balance Ratio is
         maintained); and third, any remaining principal to REMIC I Regular
         Interest I-LTXX.

                  (2)(I) On each Distribution Date, the Trustee shall withdraw
from the Distribution Account that portion of Available Funds for such
Distribution Date consisting of the Group I Interest Remittance Amount for such
Distribution Date, and make the following disbursements and transfers in the
order of priority described below, in each case to the extent of the Group I
Interest Remittance Amount remaining for such Distribution Date:

                  (i) to the Holders of the Class A-1 Certificates, the Monthly
         Interest Distributable Amount and the Unpaid Interest Shortfall Amount,
         if any, for such Certificates for such Distribution Date; and

                  (ii) to the Holders of the Class A-2 Certificates, an amount
         equal to the excess, if any, of (x) the amount required to be
         distributed pursuant to Section 4.01(a)(2)(II)(i) below for such
         Distribution Date over (y) the amount actually distributed pursuant to
         such section from the Group II Interest Remittance Amount.

                  (II) On each Distribution Date the Trustee shall withdraw from
the Distribution Account that portion of Available Funds for such Distribution
Date consisting of the Group II Interest Remittance Amount for such Distribution
Date, and make the following disbursements and transfers in the order of
priority described below, in each case to the extent of the Group II Interest
Remittance Amount remaining for such Distribution Date:

                  (i) to the Holders of the Class A-2 Certificates, the Monthly
         Interest Distributable Amount and the Unpaid Interest Shortfall Amount,
         if any, for such Certificates for such Distribution Date; and

                  (ii) to the Holders of the Class A-1 Certificates, an amount
         equal to the excess, if any, of (x) the amount required to be
         distributed pursuant to Section 4.01(a)(2)(I)(i) above for such
         Distribution Date over (y) the amount actually distributed pursuant to
         such section from the Group I Interest Remittance Amount.

                  (III) On each Distribution Date, following the distributions
made pursuant to Section 4.01(a)(2)(I) and (II) above, the Trustee shall make
the following disbursements and transfers in the order of priority described
below, in each case to the extent of the sum of the Group I Interest Remittance
Amount and the Group II Interest Remittance Amount remaining undistributed for
such Distribution Date:

                  (i) to the Holders of the Class M-1 Certificates, the Monthly
         Interest Distributable Amount allocable to such Certificates;

                  (ii) to the Holders of the Class M-2 Certificates, the Monthly
         Interest Distributable Amount allocable to such Certificates;

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<PAGE>

                  (iii) to the Holders of the Class M-3 Certificates, the
         Monthly Interest Distributable Amount allocable to such Certificates;

                  (iv) to the Holders of the Class M-4 Certificates, the Monthly
         Interest Distributable Amount allocable to such Certificates; and

                  (v) to the Holders of the Class MV-5 Certificates and the
         Class MF-5 Certificates on a PRO RATA basis based on the respective
         Monthly Interest Distributable Amount allocable to such Classes
         Certificates.

                  (3)(I) On each Distribution Date (a) prior to the Stepdown
Date or (b) on which a Trigger Event is in effect, distributions in respect of
principal to the extent of the Group I Principal Distribution Amount shall be
made in the following amounts and order of priority:

                  (i) first, to the Holders of the Class A-1 Certificates, until
         the Certificate Principal Balance thereof has been reduced to zero; and

                  (ii) second, after taking into account the amount distributed
         to the Holders of the Class A-2 Certificates pursuant to Section
         4.01(a)(3)(II)(i) below on such Distribution Date, to the Holders of
         the Class A-2 Certificates, until the Certificate Principal Balance
         thereof has been reduced to zero.

                  (II) On each Distribution Date (a) prior to the Stepdown Date
or (b) on which a Trigger Event is in effect, distributions in respect of
principal to the extent of the Group II Principal Distribution Amount shall be
made in the following amounts and order of priority:

                  (i) first, to the Holders of the Class A-2 Certificates, until
         the Certificate Principal Balance thereof has been reduced to zero; and

                  (ii) second, after taking into account the amount distributed
         to the Holders of the Class A-1 Certificates pursuant to Section
         4.01(a)(3)(I)(i) above on such Distribution Date, to the Holders of the
         Class A-1 Certificates, until the Certificate Principal Balance thereof
         has been reduced to zero.

                  (III) On each Distribution Date (a) prior to the Stepdown Date
or (b) on which a Trigger Event is in effect, distributions in respect of
principal to the extent of the sum of the Group I Principal Distribution Amount
and the Group II Principal Distribution Amount remaining undistributed for such
Distribution Date shall be made in the following amounts and order of priority:

                  (i) first, to the Holders of the Class M-1 Certificates, until
         the Certificate Principal Balance thereof has been reduced to zero;

                  (ii) second, to the Holders of the Class M-2 Certificates,
         until the Certificate Principal Balance thereof has been reduced to
         zero;

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<PAGE>

                  (iii) third, to the Holders of the Class M-3 Certificates,
         until the Certificate Principal Balance thereof has been reduced to
         zero;

                  (iv) fourth, to the Holders of the Class M-4 Certificates,
         until the Certificate Principal Balance thereof has been reduced to
         zero; and

                  (v) fifth, to the Holders of the Class MV-5 Certificates and
         the Class MF-5 Certificates on a PRO RATA basis, based on the
         respective Certificate Principal Balances of such Classes of
         Certificates, until the Certificate Principal Balance of such
         Certificates has been reduced to zero.

                  (IV) On each Distribution Date (a) on or after the Stepdown
Date and (b) on which a Trigger Event is not in effect, distributions in respect
of principal to the extent of the Group I Principal Distribution Amount shall be
made in the following amounts and order of priority:

                  (i) first, to the Holders of the Class A-1 Certificates, the
         Class A-1 Principal Distribution Amount until the Certificate Principal
         Balance thereof has been reduced to zero;

                  (ii) second, to the extent of the portion, if any, of the
         Class A-1 Principal Distribution Amount remaining undistributed
         pursuant to Section 4.01(a)(3)(IV)(i) above on such Distribution Date,
         and after taking into account the amount distributed to the Holders of
         the Class A-2 Certificates pursuant to Section 4.01(a)(3)(V)(i) below
         on such Distribution Date, to the Holders of the Class A-2
         Certificates, until the Certificate Principal Balance thereof has been
         reduced to zero; and

                  (iii) third, to the Holders of the Class A-2 Certificates, an
         amount equal to the excess, if any, of (x) the amount required to be
         distributed pursuant to Section 4.01(a)(3)(V)(i) below for such
         Distribution Date over (y) the sum of (A) the amount actually
         distributed pursuant to Section 4.01(a)(3)(V)(i) below from the Group
         II Principal Distribution Amount on such Distribution Date and (B) the
         amount, if any, distributed to the Holders of the Class A-2
         Certificates pursuant to Section 4.01(a)(3)(IV)(ii) above on such
         Distribution Date.

                  (V) On each Distribution Date (a) on or after the Stepdown
Date and (b) on which a Trigger Event is not in effect, distributions in respect
of principal to the extent of the Group II Principal Distribution Amount shall
be made in the following amounts and order of priority:

                  (i) first, to the Holders of the Class A-2 Certificates, the
         Class A-2 Principal Distribution Amount until the Certificate Principal
         Balance thereof has been reduced to zero;

                  (ii) second, to the extent of the portion, if any, of the
         Class A-2 Principal Distribution Amount remaining undistributed
         pursuant to Section 4.01(a)(3)(V)(i) above on such Distribution Date,
         and after taking into account the amount distributed to the Holders of
         the Class A-1 Certificates pursuant to Section 4.01(a)(3)(IV)(i) above
         on such Distribution Date, to the Holders of the Class A-1
         Certificates, until the Certificate Principal Balance thereof has been
         reduced to zero; and

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<PAGE>

                  (iii) third, to the Holders of the Class A-1 Certificates, an
         amount equal to the excess, if any, of (x) the amount required to be
         distributed pursuant to Section 4.01(a)(3)(IV)(i) above for such
         Distribution Date over (y) the sum of (A) the amount actually
         distributed pursuant to Section 4.01(a)(3)(IV)(i) above from the Group
         I Principal Distribution Amount on such Distribution Date and (B) the
         amount, if any, distributed to the Holders of the Class A-1
         Certificates pursuant to Section 4.01(a)(3)(V)(ii) above on such
         Distribution Date.

                  (VI) On each Distribution Date (a) on or after the Stepdown
Date and (b) on which a Trigger Event is not in effect, distributions in respect
of principal to the extent of the sum of the Group I Principal Distribution
Amount and the Group II Principal Distribution Amount remaining undistributed
for such Distribution Date shall be made in the following amounts and order of
priority:

                  (i) first, to the Holders of the Class M-1 Certificates, the
         Class M-1 Principal Distribution Amount until the Certificate Principal
         Balance thereof has been reduced to zero;

                  (ii) second, to the Holders of the Class M-2 Certificates, the
         Class M-2 Principal Distribution Amount until the Certificate Principal
         Balance thereof has been reduced to zero;

                  (iii) third, to the Holders of the Class M-3 Certificates, the
         Class M-3 Principal Distribution Amount until the Certificate Principal
         Balance thereof has been reduced to zero;

                  (iv) fourth, to the Holders of the Class M-4 Certificates, the
         Class M-4 Principal Distribution Amount until the Certificate Principal
         Balance thereof has been reduced to zero; and

                  (v) fifth, to the Holders of the Class MV-5 Certificates and
         the Class MF-5 Certificates, the Class M-5 Principal Distribution
         Amount, on a PRO RATA basis, based on the respective Certificate
         Principal Balances of such Classes of Certificates, until the
         Certificate Principal Balances of such Certificates have been reduced
         to zero.

                  (4) On each Distribution Date, the Net Monthly Excess Cashflow
shall be distributed as follows:

                  (i) to the Holders of the Class or Classes of Certificates
         then entitled to receive distributions in respect of principal, in an
         amount equal to any Extra Principal Distribution Amount, distributable
         to such Holders as part of the Group I Principal Distribution Amount
         and/or the Group II Principal Distribution Amount as described under
         Section 4.01(a)(3) above;

                  (ii) to the Holders of the Class M-1 Certificates, in an
         amount equal to the Unpaid Interest Shortfall Amount allocable to such
         Certificates;

                  (iii) to the Holders of the Class M-1 Certificates, in an
         amount equal to the Allocated Realized Loss Amount allocable to such
         Certificates;

                                      -93-

<PAGE>

                  (iv) to the Holders of the Class M-2 Certificates, in an
         amount equal to the Unpaid Interest Shortfall Amount allocable to such
         Certificates;

                  (v) to the Holders of the Class M-2 Certificates, in an amount
         equal to the Allocated Realized Loss Amount allocable to such
         Certificates;

                  (vi) to the Holders of the Class M-3 Certificates, in an
         amount equal to the Unpaid Interest Shortfall Amount allocable to such
         Certificates;

                  (vii) to the Holders of the Class M-3 Certificates, in an
         amount equal to the Allocated Realized Loss Amount allocable to such
         Certificates;

                  (viii) to the Holders of the Class M-4 Certificates, in an
         amount equal to the Unpaid Interest Shortfall Amount allocable to such
         Certificates;

                  (ix) to the Holders of the Class M-4 Certificates, in an
         amount equal to the Allocated Realized Loss Amount allocable to such
         Certificates;

                  (x) to the Holders of the Class MV-5 Certificates and the
         Class MF-5 Certificates, on a PRO RATA basis, based on the respective
         Unpaid Interest Shortfall Amount allocable to such Classes of
         Certificates;

                  (xi) to the Holders of the Class MV-5 Certificates and the
         Class MF-5 Certificates, on a PRO RATA basis, based on the respective
         Allocated Realized Loss Amount allocable to such Classes of
         Certificates;

                  (xii) to the Net WAC Rate Carryover Reserve Account, the
         amount of any Net WAC Rate Carryover Amount and any other amounts
         required by Section 3.28, after taking into account amounts received
         under the Cap Contract;

                  (xiii) to the Holders of the Class CE Certificates, the
         Monthly Interest Distributable Amount for such Class and any remaining
         Overcollateralization Release Amount for such Distribution Date;

                  (xiv) if such Distribution Date follows the Prepayment Period
         during which occurs the latest date on which a Prepayment Charge may be
         required to be paid in respect of any Mortgage Loans, to the Holders of
         the Class P Certificates, in reduction of the Certificate Principal
         Balance thereof, until the Certificate Principal Balance thereof is
         reduced to zero; and

                  (xv) any remaining amounts to the Holders of the Residual
         Certificates (in respect of the appropriate Class R Interest).

                  Without limiting the provisions of Section 9.01(b), by
acceptance of the Residual Certificates the Holders of the Residual Certificates
agree, and it is the understanding of the parties hereto, that for so long as
any of the notes issued pursuant to the Indenture are outstanding or any

                                      -94-

<PAGE>

amounts are reimbursable or payable to the NIMS Insurer in accordance with the
terms of the Indenture, to pledge their rights to receive any amounts otherwise
distributable to the Holders of the Class R Certificates (and such rights are
hereby assigned and transferred) to the Holders of the Class CE Certificates.

                  (b) On each Distribution Date, after making the distributions
of the Available Funds as set forth above, the Trustee will FIRST, withdraw from
the Net WAC Rate Carryover Reserve Account all income from the investment of
funds in the Net WAC Rate Carryover Reserve Account and distribute such amount
to the Holders of the Class CE Certificates, and SECOND, withdraw from the Net
WAC Rate Carryover Reserve Account, to the extent of amounts remaining on
deposit therein, the amount of any Net WAC Rate Carryover Amount for such
Distribution Date and distribute such amount first, concurrently to the Class
A-1 Certificates and the Class A-2 Certificates, on a PRO RATA basis based on
the Net WAC Rate Carryover Amounts for each such Class, until each such amount
has been distributed in full; second, to the Class M-1 Certificates, third, to
the Class M-2 Certificates, fourth, to the Class M-3 Certificates, fifth, to the
Class M-4 Certificates and sixth, to the Class MV-5 Certificates and the Class
MF-5 Certificates on a PRO RATA basis based on the respective Net WAC Carryover
Amount allocable to each such Class.

                  On each Distribution Date, the Trustee shall withdraw any
amounts then on deposit in the Distribution Account that represent (i)
Prepayment Charges collected by the Master Servicer in connection with the
Principal Prepayment of any of the Mortgage Loans or (ii) any Master Servicer
Prepayment Charge Payment Amount, and shall distribute such amounts to the
Holders of the Class P Certificates. Such distributions shall not be applied to
reduce the Certificate Principal Balance of the Class P Certificates.

                  (c) All distributions made with respect to each Class of
Certificates on each Distribution Date shall be allocated PRO RATA among the
outstanding Certificates in such Class based on their respective Percentage
Interests. Distributions in respect of each Class of Certificates on each
Distribution Date will be made to the Holders of the respective Class of record
on the related Record Date (except as otherwise provided in Section 4.01(e) or
Section 9.01 respecting the final distribution on such Class), based on the
aggregate Percentage Interest represented by their respective Certificates, and
shall be made by wire transfer of immediately available funds to the account of
any such Holder at a bank or other entity having appropriate facilities
therefor, if such Holder shall have so notified the Trustee in writing at least
five Business Days prior to the Record Date immediately prior to such
Distribution Date and is the registered owner of Certificates having an initial
aggregate Certificate Principal Balance or Notional Amount that is in excess of
the lesser of (i) $5,000,000 or (ii) two-thirds of the initial Certificate
Principal Balance or Notional Amount of such Class of Certificates, or otherwise
by check mailed by first class mail to the address of such Holder appearing in
the Certificate Register. The final distribution on each Certificate will be
made in like manner, but only upon presentment and surrender of such Certificate
at the Corporate Trust Office of the Trustee or such other location specified in
the notice to Certificateholders of such final distribution.

                  Each distribution with respect to a Book-Entry Certificate
shall be paid to the Depository, as Holder thereof, and the Depository shall be
responsible for crediting the amount of such distribution to the accounts of its
Depository Participants in accordance with its normal

                                      -95-

<PAGE>

procedures. Each Depository Participant shall be responsible for disbursing such
distribution to the Certificate Owners that it represents and to each indirect
participating brokerage firm (a "brokerage firm" or "indirect participating
firm") for which it acts as agent. Each brokerage firm shall be responsible for
disbursing funds to the Certificate Owners that it represents. None of the
Trustee, the Depositor or the Master Servicer shall have any responsibility
therefor except as otherwise provided by this Agreement or applicable law.

                  (d) The rights of the Certificateholders to receive
distributions in respect of the Certificates, and all interests of the
Certificateholders in such distributions, shall be as set forth in this
Agreement. None of the Holders of any Class of Certificates, the Trustee or the
Master Servicer shall in any way be responsible or liable to the Holders of any
other Class of Certificates in respect of amounts properly previously
distributed on the Certificates.

                  (e) Except as otherwise provided in Section 9.01, whenever the
Trustee expects that the final distribution with respect to any Class of
Certificates will be made on the next Distribution Date, the Trustee shall, no
later than three (3) days before the related Distribution Date, mail to each
Holder on such date of such Class of Certificates a notice to the effect that:

                  (i) the Trustee expects that the final distribution with
         respect to such Class of Certificates will be made on such Distribution
         Date but only upon presentation and surrender of such Certificates at
         the office of the Trustee therein specified, and

                  (ii) no interest shall accrue on such Certificates from and
         after the end of the related Accrual Period.

                  Any funds not distributed to any Holder or Holders of
Certificates of such Class on such Distribution Date because of the failure of
such Holder or Holders to tender their Certificates shall, on such date, be set
aside and held in trust by the Trustee and credited to the account of the
appropriate non-tendering Holder or Holders. If any Certificates as to which
notice has been given pursuant to this Section 4.01(e) shall not have been
surrendered for cancellation within six months after the time specified in such
notice, the Trustee shall mail a second notice to the remaining non-tendering
Certificateholders to surrender their Certificates for cancellation in order to
receive the final distribution with respect thereto. If within one year after
the second notice all such Certificates shall not have been surrendered for
cancellation, the Trustee shall, directly or through an agent, mail a final
notice to the remaining non-tendering Certificateholders concerning surrender of
their Certificates but shall continue to hold any remaining funds for the
benefit of non-tendering Certificateholders. The costs and expenses of
maintaining the funds in trust and of contacting such Certificateholders shall
be paid out of the assets remaining in the Trust Fund. If within one year after
the final notice any such Certificates shall not have been surrendered for
cancellation, the Trustee shall pay to UBS Warburg LLC all such amounts, and all
rights of non-tendering Certificateholders in or to such amounts shall thereupon
cease. No interest shall accrue or be payable to any Certificateholder on any
amount held in trust by the Trustee as a result of such Certificateholder's
failure to surrender its Certificate(s) for final payment thereof in accordance
with this Section 4.01(e). Any such amounts held in trust by the Trustee shall
be held in an Eligible Account and the Trustee may direct any depository
institution maintaining such account to invest the funds in one or more
Permitted Investments. All income and gain realized from the investment of funds
deposited

                                      -96-

<PAGE>

in such accounts held in trust by the Trustee shall be for the benefit of the
Trustee; provided, however, that the Trustee shall deposit in such account the
amount of any loss of principal incurred in respect of any such Permitted
Investment made with funds in such accounts immediately upon the realization of
such loss.

                  (f) Notwithstanding anything to the contrary herein, (i) in no
event shall the Certificate Principal Balance of a Class A Certificate or a
Mezzanine Certificate be reduced more than once in respect of any particular
amount both (a) allocated to such Certificate in respect of Realized Losses
pursuant to Section 4.04 and (b) distributed to the Holder of such Certificate
in reduction of the Certificate Principal Balance thereof pursuant to this
Section 4.01 from Net Monthly Excess Cashflow and (ii) in no event shall the
Uncertificated Balance of a REMIC I Regular Interest be reduced more than once
in respect of any particular amount both (a) allocated to such REMIC I Regular
Interest in respect of Realized Losses pursuant to Section 4.04 and (b)
distributed on such REMIC I Regular Interest in reduction of the Uncertificated
Balance thereof pursuant to this Section 4.01.

                  SECTION 4.02.             Statements to Certificateholders.

                  On each Distribution Date, the Trustee shall prepare and make
available to each Holder of the Regular Certificates and the NIMS Insurer, a
statement as to the distributions made on such Distribution Date setting forth:

                  (i) the amount of the distribution made on such Distribution
         Date to the Holders of the Certificates of each Class allocable to
         principal, and the amount of the distribution made on such Distribution
         Date to the Holders of the Class P Certificates allocable to Prepayment
         Charges and Master Servicer Prepayment Charge Payment Amounts;

                  (ii) the amount of the distribution made on such Distribution
         Date to the Holders of the Certificates of each Class allocable to
         interest;

                  (iii) the aggregate Servicing Fee received by the Master
         Servicer during the related Due Period and such other customary
         information as the Trustee deems necessary or desirable, or which a
         Certificateholder reasonably requests, to enable Certificateholders to
         prepare their tax returns;

                  (iv) the aggregate amount of Advances for such Distribution
         Date;

                  (v) the aggregate Stated Principal Balance of the Mortgage
         Loans and any REO Properties as of the close of business on such
         Distribution Date;

                  (vi) the number, aggregate Principal Balance, weighted average
         remaining term to maturity and weighted average Mortgage Rate of the
         Mortgage Loans as of the related Due Date;

                  (vii) the number and aggregate unpaid principal balance of
         Mortgage Loans (a) delinquent 30 to 59 days, (b) delinquent 60 to 89
         days, (c) delinquent 90 or more days, in

                                      -97-

<PAGE>

         each case, as of the last day of the preceding calendar month, (d) as
         to which foreclosure proceedings have been commenced and (e) with
         respect to which the related Mortgagor has filed for protection under
         applicable bankruptcy laws, with respect to whom bankruptcy proceedings
         are pending or with respect to whom bankruptcy protection is in force;

                  (viii) the total number and cumulative principal balance of
         all REO Properties as of the close of business on the last day of the
         preceding Prepayment Period;

                  (ix) [reserved];

                  (x) the aggregate amount of Principal Prepayments made during
         the related Prepayment Period;

                  (xi) the aggregate amount of Realized Losses incurred during
         the related Prepayment Period and the aggregate amount of Realized
         Losses incurred since the Closing Date;

                  (xii) the aggregate amount of Extraordinary Trust Fund
         Expenses withdrawn from the Collection Account or the Distribution
         Account for such Distribution Date;

                  (xiii) the aggregate Certificate Principal Balance and
         Notional Amount, as applicable, of each Class of Certificates, after
         giving effect to the distributions, and allocations of Realized Losses,
         made on such Distribution Date, separately identifying any reduction
         thereof due to allocations of Realized Losses;

                  (xiv) the Certificate Factor for each such Class of
         Certificates applicable to such Distribution Date;

                  (xv) the Monthly Interest Distributable Amount in respect of
         the Class A Certificates, the Mezzanine Certificates and the Class CE
         Certificates for such Distribution Date and the Unpaid Interest
         Shortfall Amount, if any, with respect to the Class A Certificates and
         the Mezzanine Certificates on such Distribution Date, separately
         identifying any reduction thereof due to allocations of Realized
         Losses, Prepayment Interest Shortfalls and Relief Act Interest
         Shortfalls;

                  (xvi) the aggregate amount of any Prepayment Interest
         Shortfall for such Distribution Date, to the extent not covered by
         payments by the Master Servicer pursuant to Section 3.24;

                  (xvii) the aggregate amount of Relief Act Interest Shortfalls
         for such Distribution Date;

                  (xviii) the Overcollateralization Target Amount,
         Overcollateralized Amount and Overcollateralization Deficiency Amount
         and the Credit Enhancement Percentage for such Distribution Date;

                                      -98-

<PAGE>

                  (xix) the respective Pass-Through Rates applicable to the
         Class A Certificates, the Mezzanine Certificates and the Class CE
         Certificates for such Distribution Date and the Pass-Through Rate
         applicable to the Class A Certificates and the Mezzanine Certificates
         for the immediately succeeding Distribution Date;

                  (xx) [reserved];

                  (xxi) the Aggregate Loss Severity Percentage;

                  (xxii) when the Stepdown Date or Trigger Event has occurred;

                  (xxiii)  the Available Funds;

                  (xxiv) the Net WAC Rate Carryover Amount for the Class A
         Certificates and the Mezzanine Certificates, if any, for such
         Distribution Date, the amount remaining unpaid after reimbursements
         therefor on such Distribution Date and any amounts received under the
         Cap Contract;

                  (xxv) (A) the amount of payments received related to claims
         under the PMI Policy during the related Prepayment Period (and the
         number of Mortgage Loans to which such payments related) and (B) the
         cumulative amount of payments received related to claims under the PMI
         Policy since the Closing Date (and the number of Mortgage Loans to
         which such payments related); and

                  (xxvi) (A) the dollar amount of claims made under the PMI
         Policy that were denied during the Prepayment Period (and the number of
         Mortgage Loans to which such denials related) and (B) the dollar amount
         of the cumulative claims made under the PMI Policy that were denied
         since the Closing Date (and the number of Mortgage Loans to which such
         denials related).

                  The Trustee will make such statement (and, at its option, any
additional files containing the same information in an alternative format)
available each month to Certificateholders, the NIMS Insurer and the Rating
Agencies via the Trustee's internet website. The Trustee's internet website
shall initially be located at "www.ctslink.com". Assistance in using the website
can be obtained by calling the Trustee's customer service desk at (301)
815-6600. Parties that are unable to use the above distribution option are
entitled to have a paper copy mailed to them via first class mail by calling the
customer service desk and indicating such. The Trustee shall have the right to
change the way such statements are distributed in order to make such
distribution more convenient and/or more accessible to the above parties and the
Trustee shall provide timely and adequate notification to all above parties
regarding any such changes. As a condition to access the Trustee's internet
website, the Trustee may require registration and the acceptance of a
disclaimer. The Trustee will not be liable for the dissemination of information
in accordance with this Agreement. The Trustee 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 thereto).

                                      -99-

<PAGE>

                  In the case of information furnished pursuant to subclauses
(i) through (iii) above, the amounts shall be expressed as a dollar amount per
Single Certificate of the relevant Class.

                  Within a reasonable period of time after the end of each
calendar year, the Trustee shall, upon written request, furnish to each Person
who at any time during the calendar year was a Holder of a Regular Certificate
and the NIMS Insurer a statement containing the information set forth in
subclauses (i) through (iii) above, aggregated for such calendar year or
applicable portion thereof during which such person was a Certificateholder.
Such obligation of the Trustee shall be deemed to have been satisfied to the
extent that substantially comparable information shall be provided by the
Trustee pursuant to any requirements of the Code as from time to time are in
force.

                  On each Distribution Date, the Trustee shall forward to the
Depositor, the NIMS Insurer, the Trustee, to each Holder of a Residual
Certificate and to the Master Servicer, a copy of the reports forwarded to the
Regular Certificateholders on such Distribution Date and a statement setting
forth the amounts, if any, actually distributed with respect to the Residual
Certificates, respectively, on such Distribution Date.

                  Within a reasonable period of time after the end of each
calendar year, the Trustee shall furnish to each Person who at any time during
the calendar year was a Holder of a Residual Certificate and the NIMS Insurer a
statement setting forth the amount, if any, actually distributed with respect to
the Residual Certificates, as appropriate, aggregated for such calendar year or
applicable portion thereof during which such Person was a Certificateholder.

                  The Trustee shall, upon request, furnish to each
Certificateholder and the NIMS Insurer, during the term of this Agreement, such
periodic, special, or other reports or information, whether or not provided for
herein, as shall be reasonable with respect to the Certificateholder, or
otherwise with respect to the purposes of this Agreement, all such reports or
information to be provided at the expense of the Certificateholder in accordance
with such reasonable and explicit instructions and directions as the
Certificateholder may provide. For purposes of this Section 4.02, the Trustee's
duties are limited to the extent that the Trustee receives timely reports as
required from the Master Servicer.

                  On each Distribution Date the Trustee shall provide Bloomberg
Financial Markets, L.P. ("Bloomberg") CUSIP level factors for each class of
Certificates as of such Distribution Date, using a format and media mutually
acceptable to the Trustee and Bloomberg.

                  SECTION 4.03.             Remittance Reports; Advances.

                  (a) On the second Business Day following each Determination
Date but in no event later than the earlier of (i) such date which would allow
the indenture trustee to submit a claim to the NIMS Insurer under the Indenture
so as to allow a timely payment by the NIMS Insurer under the insurance policy
related to the notes insured by the NIMS Insurer and (ii) the 20th day of each
month (or if such 20th day is not a Business Day, the preceding Business Day),
the Master Servicer shall deliver to the Trustee and the NIMS Insurer by
telecopy or electronic mail (or by such other means as the Master Servicer and
the Trustee may agree from time to time) a Remittance Report with respect to the
related Distribution Date. On the same date, the Master Servicer shall forward
to the

                                              -100-

<PAGE>

Trustee by overnight mail a computer readable magnetic tape or electronically
transmit (in a format acceptable to the Trustee) a data file containing the
information set forth in such Remittance Report with respect to the related
Distribution Date. Such Remittance Report will include (i) the amount of
Advances to be made by the Master Servicer in respect of the related
Distribution Date, the aggregate amount of Advances outstanding after giving
effect to such Advances, and the aggregate amount of Nonrecoverable Advances in
respect of such Distribution Date and (ii) such other information with respect
to the Mortgage Loans as the Trustee may reasonably require to perform the
calculations necessary to make the distributions contemplated by Section 4.01
and to prepare the statements to Certificateholders contemplated by Section
4.02. The Trustee shall not be responsible to recompute, recalculate or verify
any information provided to it by the Master Servicer.

                  (b) The amount of Advances to be made by the Master Servicer
for any Distribution Date shall equal, subject to Section 4.03(d), the sum of
(i) the aggregate amount of Monthly Payments (with each interest portion thereof
net of the related Servicing Fee), due on the related Due Date in respect of the
Mortgage Loans, which Monthly Payments were delinquent as of the close of
business on the related Determination Date and (ii) with respect to each REO
Property, which REO Property was acquired during or prior to the related
Prepayment Period and as to which REO Property an REO Disposition did not occur
during the related Prepayment Period, an amount equal to the excess, if any, of
the REO Imputed Interest on such REO Property for the most recently ended
calendar month, over the net income from such REO Property transferred to the
Distribution Account pursuant to Section 3.23 for distribution on such
Distribution Date. For purposes of the preceding sentence, the Monthly Payment
on each Balloon Mortgage Loan with a delinquent Balloon Payment is equal to the
assumed monthly payment that would have been due on the related Due Date based
on the original principal amortization schedule for the such Balloon Mortgage
Loan.

                  By 1:00 p.m. New York time on the Master Servicer Remittance
Date, the Master Servicer shall remit in immediately available funds to the
Trustee for deposit in the Distribution Account an amount equal to the aggregate
amount of Advances, if any, to be made in respect of the Mortgage Loans and REO
Properties for the related Distribution Date either (i) from its own funds or
(ii) from the Collection Account, to the extent of funds held therein for future
distribution (in which case it will cause to be made an appropriate entry in the
records of Collection Account that amounts held for future distribution have
been, as permitted by this Section 4.03, used by the Master Servicer in
discharge of any such Advance) or (iii) in the form of any combination of (i)
and (ii) aggregating the total amount of Advances to be made by the Master
Servicer with respect to the Mortgage Loans and REO Properties. Any amounts held
for future distribution and so used shall be appropriately reflected in the
Master Servicer's records and replaced by the Master Servicer by deposit in the
Collection Account on or before any future Master Servicer Remittance Date to
the extent that the Available Funds for the related Distribution Date
(determined without regard to Advances to be made on the Master Servicer
Remittance Date) shall be less than the total amount that would be distributed
to the Certificateholders pursuant to Section 4.01 on such Distribution Date if
such amounts held for future distributions had not been so used to make
Advances. The Trustee will provide notice to the Master Servicer and the NIMS
Insurer by telecopy by the close of business on the third Business Day prior to
the Distribution Date in the event that the amount remitted by the Master
Servicer to the Trustee on such date is less than the Advances required to be
made by the Master Servicer for the related Distribution Date.

                                      -101-

<PAGE>

                  (c) The obligation of the Master Servicer to make such
Advances is mandatory, notwithstanding any other provision of this Agreement but
subject to (d) below, and, with respect to any Mortgage Loan or REO Property,
shall continue until a Final Recovery Determination in connection therewith or
the removal thereof from the Trust Fund pursuant to any applicable provision of
this Agreement, except as otherwise provided in this Section.

                  (d) Notwithstanding anything herein to the contrary, no
Advance or Servicing Advance shall be required to be made hereunder by the
Master Servicer if such Advance or Servicing Advance would, if made, constitute
a Nonrecoverable Advance or Nonrecoverable Servicing Advance, respectively. The
determination by the Master Servicer that it has made a Nonrecoverable Advance
or a Nonrecoverable Servicing Advance or that any proposed Advance or Servicing
Advance, if made, would constitute a Nonrecoverable Advance or Nonrecoverable
Servicing Advance, respectively, shall be evidenced by an Officers' Certificate
of the Master Servicer delivered to the Depositor, the NIMS Insurer and the
Trustee.

                  SECTION 4.04.             Allocation of Realized Losses.

                  (a) Prior to each Determination Date, the Master Servicer
shall determine as to each Mortgage Loan and REO Property: (i) the total amount
of Realized Losses, if any, incurred in connection with any Final Recovery
Determinations made during the related Prepayment Period; and (ii) the
respective portions of such Realized Losses allocable to interest and allocable
to principal. Prior to each Determination Date, the Master Servicer shall also
determine as to each Mortgage Loan: (i) the total amount of Realized Losses, if
any, incurred in connection with any Deficient Valuations made during the
related Prepayment Period; and (ii) the total amount of Realized Losses, if any,
incurred in connection with Debt Service Reductions in respect of Monthly
Payments due during the related Due Period. The information described in the
preceding sentence that is to be supplied by the Master Servicer shall be
evidenced by an Officers' Certificate delivered to the Trustee by the Master
Servicer prior to the Determination Date immediately following the end of the
Prepayment Period during which any such Realized Loss was incurred.

                  (b) All Realized Losses on the Mortgage Loans shall be
allocated by the Trustee on each Distribution Date as follows: first, to Net
Monthly Excess Cashflow; second, to the Class CE Certificates, until the
Certificate Principal Balance thereof has been reduced to zero; third, to the
Class MV-5 Certificates and the Class MF-5 Certificates, on a PRO RATA basis,
based on the respective Certificate Principal Balances of such Classes of
Certificates, until the respective Certificate Principal Balances thereof have
been reduced to zero; fourth, to the Class M-4 Certificates, until the
Certificate Principal Balance thereof has been reduced to zero; fifth, to the
Class M-3 Certificates, until the Certificate Principal Balance thereof has been
reduced to zero; sixth, to the Class M-2 Certificates, until the Certificate
Principal Balance thereof has been reduced to zero; and seventh, to the Class
M-1 Certificates, until the Certificate Principal Balance thereof has been
reduced to zero. All Realized Losses to be allocated to the Certificate
Principal Balances of all Classes on any Distribution Date shall be so allocated
after the actual distributions to be made on such date as provided above. All
references above to the Certificate Principal Balance of any Class of
Certificates shall be to the Certificate Principal Balance of such Class
immediately prior to the relevant Distribution Date, before reduction thereof by
any Realized Losses, in each case to be allocated to such Class of Certificates,
on such Distribution Date.

                                      -102-

<PAGE>

                  Any allocation of Realized Losses to a Mezzanine Certificate
on any Distribution Date shall be made by reducing the Certificate Principal
Balance thereof by the amount so allocated; any allocation of Realized Losses to
a Class CE Certificate shall be made by reducing the amount otherwise payable in
respect thereof pursuant to Section 4.01(d)(xv). No allocations of any Realized
Losses shall be made to the Certificate Principal Balances of the Class A
Certificates or the Class P Certificates.

                  As used herein, an allocation of a Realized Loss on a "PRO
RATA basis" among two or more specified Classes of Certificates means an
allocation on a PRO RATA basis, among the various Classes so specified, to each
such Class of Certificates on the basis of their then outstanding Certificate
Principal Balances prior to giving effect to distributions to be made on such
Distribution Date. All Realized Losses and all other losses allocated to a Class
of Certificates hereunder will be allocated among the Certificates of such Class
in proportion to the Percentage Interests evidenced thereby.

                  (c)(i) The REMIC I Marker Percentage of all Realized Losses on
the Mortgage Loans shall be allocated by the Trustee on each Distribution Date
to the following REMIC I Regular Interests in the specified percentages, as
follows: first, to Uncertificated Interest payable to the REMIC I Regular
Interest I-LTAA and REMIC I Regular Interest I-LTZZ up to an aggregate amount
equal to the REMIC I Interest Loss Allocation Amount, 98% and 2%, respectively;
second, to the Uncertificated Balances of the REMIC I Regular Interest I-LTAA
and REMIC I Regular Interest I- LTZZ up to an aggregate amount equal to the
REMIC I Principal Loss Allocation Amount, 98% and 2%, respectively; third, to
the Uncertificated Balances of REMIC I Regular Interest I-LTAA, REMIC I Regular
Interest I-LTMV5, REMIC Regular Interest I-LTMF5, and REMIC I Regular Interest
I- LTZZ, 98%, 0.50%, 0.50% and 1%, respectively, until the Uncertificated
Balances of REMIC I Regular Interest I-LTMV5 and REMIC I Regular Interest
I-LTMF5 have been reduced to zero; fourth to the Uncertificated Balances of
REMIC I Regular Interest I-LTAA, REMIC I Regular Interest I- LTM4 and REMIC I
Regular Interest I-LTZZ, 98%, 1% and 1%, respectively, until the Uncertificated
Balance of REMIC I Regular Interest I-LTM4 has been reduced to zero; fifth to
the Uncertificated Balances of REMIC I Regular Interest I-LTAA, REMIC I Regular
Interest I-LTM2 and REMIC I Regular Interest I-LTZZ, 98%, 1% and 1%,
respectively, until the Uncertificated Balance of REMIC I Regular Interest
I-LTM2 has been reduced to zero; and sixth to the Uncertificated Balances of
REMIC I Regular Interest I-LTAA, REMIC I Regular Interest I-LTM1 and REMIC I
Regular Interest II-LTZZ, 98%, 1% and 1%, respectively, until the Uncertificated
Balance of REMIC I Regular Interest I-LTM1 has been reduced to zero.

                  (ii) The REMIC I Sub WAC Allocation Percentage of all Realized
Losses shall be applied after all distributions have been made on each
Distribution Date first, so as to keep the Uncertificated Balance of each REMIC
I Regular Interest ending with the designation "GRP" equal to 0.01% of the
aggregate Stated Principal Balance of the Mortgage Loans in the related Loan
Group; second, to each REMIC I Regular Interest ending with the designation
"SUB," so that the Uncertificated Balance of each such REMIC I Regular Interest
is equal to 0.01% of the excess of (x) the aggregate Stated Principal Balance of
the Mortgage Loans in the related Loan Group over (y) the Certificate Principal
Balance of the Class A Certificate in the related Loan Group (except that if any
such excess is a larger number than in the preceding distribution period, the
least amount of Realized Losses shall be applied to such REMIC I Regular
Interests such that the REMIC I Subordinated

                                      -103-

<PAGE>

Balance Ratio is maintained); and third, any remaining Realized Losses shall be
allocated to REMIC I Regular Interest I-LTXX.

                  SECTION 4.05.             Compliance with Withholding
                                            Requirements

                  Notwithstanding any other provision of this Agreement, the
Trustee shall comply with all federal withholding requirements respecting
payments to Certificateholders of interest or original issue discount that the
Trustee reasonably believes are applicable under the Code. The consent of
Certificateholders shall not be required for such withholding. In the event the
Trustee does withhold any amount from interest or original issue discount
payments or advances thereof to any Certificateholder pursuant to federal
withholding requirements, the Trustee shall indicate the amount withheld to such
Certificateholders.

                  SECTION 4.06.             Exchange Commission; Additional
                                            Information.

                  (a) The Trustee and the Master Servicer shall reasonably
cooperate with the Depositor in connection with satisfying the reporting
requirements of the Trust Fund under the Exchange Act. The Trustee shall prepare
and sign on behalf of the Trust Fund any Forms 8-K customary for similar
securities as required by the Exchange Act and the Rules and Regulations of the
Commission thereunder, and the Trustee shall file (via the Commission's
Electronic Data Gathering and Retrieval System) such forms on behalf of the
Trust Fund. The Trustee shall prepare and the Master Servicer shall sign any
Form 10-K which includes as exhibits (i) the Certification (as defined in (b)
below), (ii) the Master Servicer's annual statement of compliance described
under Section 3.20 and (iii) the accountant's report described under Section
3.21 and the Trustee shall file (via the Commission's Electronic Data Gathering
and Retrieval System) such forms on behalf of the Trust Fund. To the extent that
the Commission requires any additional information to be filed pursuant to a
Form 10-K, the Trustee, shall prepare, the Master Servicer shall sign and the
Trustee shall promptly file an amended Form 10-K containing such additional
information. The Trustee shall subject to the provisions of Sections 8.01 and
8.02 hereof, indemnify and hold harmless the Master Servicer and its officers,
directors and Affiliates from and against any losses, damages, penalties, fines,
forfeitures, reasonable and necessary legal fees and related costs, judgments
and other costs and expenses arising out of or based upon third party claims
relating to information included in any Form 10-K provide by the Trustee other
than any losses, damages, penalties, fines, forfeitures, reasonable and
necessary legal fees and related costs arising out of third party claims
relating to information contained in the Certification, the Master Servicer's
annual statement of compliance described under Section 3.20 and the accountant's
report described under Section 3.21 which are included in such Form 10-K.

                  (b) Each Form 8-K shall be filed by the Trustee within 15 days
after each Distribution Date with a copy of the Monthly Statement for such
Distribution Date as an exhibit thereto. Prior to March 31st of each year (or
such earlier date as may be required by the Exchange Act and the Rules and
Regulations of the Commission), the Trustee shall file a Form 10-K, in substance
as required by applicable law or applicable Commission staff's interpretations.
Such Form 10-K shall include as exhibits the Master Servicer's annual statement
of compliance described under Section 3.20 and the accountant's report described
under Section 3.21, in each case to the extent they have been timely delivered
to the Trustee. If they are not so timely delivered, the Trustee shall file an
amended Form 10-K including such documents as exhibits reasonably promptly after
they are delivered to the Trustee. The Trustee shall have no liability with
respect to any failure to properly prepare or file such periodic reports
resulting from or relating to (a) the Trustee's inability or failure to obtain
any information not resulting from its own negligence or willful misconduct or
(b) any inaccuracy in such periodic reports resulting from incorrect information
provided to the Trustee by

                                     -104-

<PAGE>

the Master Servicer in a Remittance Report or otherwise. The Form 10-K shall
also include a certification in the form attached hereto as Exhibit J-1 (the
"Certification"), which shall be signed by the Master Servicer.

                  (c) In addition, the Trustee shall sign a certification (in
the form attached hereto as Exhibit J-2) for the benefit of the Master Servicer
and its officers, directors and Affiliates regarding certain aspects of the
Certification (provided, however, that the Trustee shall not undertake an
analysis of the accountant's report attached as an exhibit to the Form 10-K).
The Trustee's certification shall be delivered to the Master Servicer by no
later than March 15th of each year (or if such day is not a Business Day, the
immediately preceding Business Day) and the Master Servicer shall deliver the
Certification to the Trustee for filing no later than March 25th of each year
(or if such day is not a Business Day, the immediately preceding Business Day).

                  In addition, (i) the Trustee shall, subject to the provisions
of Sections 8.01 and 8.02, indemnify and hold harmless the Depositor and the
Master Servicer and their respective officers, directors and Affiliates from and
against any losses, damages, penalties, fines, forfeitures, reasonable and
necessary legal fees and related costs, judgments and other costs and expenses
arising out of or based upon a breach of the Trustee's obligations under this
Section 4.06(b) or the Trustee's negligence, bad faith or willful misconduct in
connection therewith, and (ii) the Master Servicer shall indemnify and hold
harmless the Depositor, the Trustee and their respective officers, directors and
Affiliates from and against any losses, damages, penalties, fines, forfeitures,
reasonable and necessary legal fees and related costs, judgments and other costs
and expenses arising out of or based upon a breach of the Master Servicer's
obligations under this Section 4.06(b) or the Master Servicer's negligence, bad
faith or willful misconduct in connection therewith. If the indemnification
provided for herein is unavailable or insufficient to hold harmless the
Depositor or the Master Servicer, then (i) the Trustee agrees that it shall
contribute to the amount paid or payable by the Depositor or the Master
Servicer, as applicable, as a result of the losses, claims, damages or
liabilities of the Depositor or the Master Servicer, as applicable, in such
proportion as is appropriate to reflect the relative fault of the or the
Depositor or the Master Servicer, as applicable, on the one hand and the Trustee
on the other in connection with a breach of the Trustee's obligations under this
Section 4.06(b) or the Trustee's negligence, bad faith or willful misconduct in
connection therewith and (ii) the Master Servicer agrees that it shall
contribute to the amount paid or payable by the Depositor or the Trustee, as
applicable, as a result of the losses, claims, damages or liabilities of the
Depositor or the Trustee, as applicable, in such proportion as is appropriate to
reflect the relative fault of the Depositor or the Trustee, as applicable, on
the one hand and the Master Servicer on the other in connection with a breach of
the Master Servicer's obligations under this Section 4.06(b) or the Master
Servicer's negligence, bad faith or willful misconduct in connection therewith.
Notwithstanding any other provision in this Agreement to the contrary, the
Master Servicer shall not have any responsibility or liability to any party
relating to the certification or information prepared, certified or distributed
by the Trustee or any other party other than the Master Servicer unless such
information was derived from erroneous or incomplete information required to be
provided by the Master Servicer under this Agreement.

                  (d) Upon any filing with the Commission pursuant to this
Section 4.06(b), the Trustee shall promptly deliver to the Depositor a copy of
any executed report, statement or information.

                                     -105-

<PAGE>

                  (e) Prior to January 30 of the first year in which the Trustee
is able to do so under applicable law, the Trustee shall file a Form 15
Suspension Notification with respect to the Trust Fund.

                                    ARTICLE V

                                THE CERTIFICATES

                  SECTION 5.01.             The Certificates.

                  (a) The Certificates in the aggregate will represent the
entire beneficial ownership interest in the Mortgage Loans and all other assets
included in REMIC I.

                  The Certificates will be substantially in the forms annexed
hereto as Exhibits A-1 through A-11. The Certificates of each Class will be
issuable in registered form only, in denominations of authorized Percentage
Interests as described in the definition thereof. Each Certificate will share
ratably in all rights of the related Class.

                  Upon original issue, the Certificates shall be executed by the
Trustee and authenticated and delivered by the Trustee to or upon the order of
the Depositor. The Certificates shall be executed by manual or facsimile
signature on behalf of the Trustee by an authorized signatory. Certificates
bearing the manual or facsimile signatures of individuals who were at any time
the proper officers of the Trustee shall bind the Trustee notwithstanding that
such individuals or any of them have ceased to hold such offices prior to the
authentication 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 there appears on such
Certificate a certificate of authentication substantially in the form provided
herein executed by the Trustee by manual signature, and such certificate of
authentication 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.

                  (b) The Class A Certificates and the Mezzanine Certificates
shall initially be issued as one or more Certificates held by the Book-Entry
Custodian or, if appointed to hold such Certificates as provided below, the
Depository and registered in the name of the Depository or its nominee and,
except as provided below, registration of such Certificates may not be
transferred by the Trustee except to another Depository that agrees to hold such
Certificates for the respective Certificate Owners with Ownership Interests
therein. The Certificate Owners shall hold their respective Ownership Interests
in and to such Certificates through the book-entry facilities of the Depository
and, except as provided below, shall not be entitled to definitive, fully
registered Certificates ("Definitive Certificates") in respect of such Ownership
Interests. All transfers by Certificate Owners of their respective Ownership
Interests in the Book-Entry Certificates shall be made in accordance with the
procedures established by the Depository Participant or brokerage firm
representing such Certificate Owner. Each Depository Participant shall only
transfer the Ownership Interests in the Book-Entry Certificates of Certificate
Owners it represents or of brokerage firms for which it acts as agent in
accordance with the Depository's normal procedures. The Trustee is hereby
initially appointed as the Book-Entry Custodian and hereby agrees to act as such
in accordance

                                      -106-

<PAGE>

herewith and in accordance with the agreement that it has with the Depository
authorizing it to act as such. The Book-Entry Custodian may, and, if it is no
longer qualified to act as such, the Book- Entry Custodian shall, appoint, by a
written instrument delivered to the Depositor, the Master Servicer and the
Trustee, any other transfer agent (including the Depository or any successor
Depository) to act as Book-Entry Custodian under such conditions as the
predecessor Book-Entry Custodian and the Depository or any successor Depository
may prescribe, provided that the predecessor Book-Entry Custodian shall not be
relieved of any of its duties or responsibilities by reason of any such
appointment of other than the Depository. If the Trustee resigns or is removed
in accordance with the terms hereof, the Trustee, the successor trustee or, if
it so elects, the Depository shall immediately succeed to its predecessor's
duties as Book-Entry Custodian. The Depositor shall have the right to inspect,
and to obtain copies of, any Certificates held as Book-Entry Certificates by the
Book-Entry Custodian.

                  The Trustee, the Master Servicer and the Depositor may for all
purposes (including the making of payments due on the Book-Entry Certificates)
deal with the Depository as the authorized representative of the Certificate
Owners with respect to the Book-Entry Certificates for the purposes of
exercising the rights of Certificateholders hereunder. The rights of Certificate
Owners with respect to the Book-Entry Certificates shall be limited to those
established by law and agreements between such Certificate Owners and the
Depository Participants and brokerage firms representing such Certificate
Owners. Multiple requests and directions from, and votes of, the Depository as
Holder of the Book-Entry Certificates with respect to any particular matter
shall not be deemed inconsistent if they are made with respect to different
Certificate Owners. The Trustee may establish a reasonable record date in
connection with solicitations of consents from or voting by Certificateholders
and shall give notice to the Depository of such record date.

                  If (i)(A) the Depositor advises the Trustee in writing that
the Depository is no longer willing or able to properly discharge its
responsibilities as Depository, and (B) the Depositor is unable to locate a
qualified successor, (ii) the Depositor at its option advises the Trustee in
writing that it elects to terminate the book-entry system through the Depository
or (iii) after the occurrence of a Master Servicer Event of Default, Certificate
Owners representing in the aggregate not less than 51% of the Ownership
Interests of the Book-Entry Certificates advise the Trustee through the
Depository, in writing, that the continuation of a book-entry system through the
Depository is no longer in the best interests of the Certificate Owners, the
Trustee shall notify all Certificate Owners, through the Depository, of the
occurrence of any such event and of the availability of Definitive Certificates
to Certificate Owners requesting the same. Upon surrender to the Trustee of the
Book- Entry Certificates by the Book-Entry Custodian or the Depository, as
applicable, accompanied by registration instructions from the Depository for
registration of transfer, the Trustee shall cause the Definitive Certificates to
be issued. Such Definitive Certificates will be issued in minimum denominations
of $50,000, except that any beneficial ownership that was represented by a Book-
Entry Certificate in an amount less than $50,000 immediately prior to the
issuance of a Definitive Certificate shall be issued in a minimum denomination
equal to the amount represented by such Book-Entry Certificate. None of the
Depositor, the Master Servicer, the Trustee shall be liable for any delay in the
delivery of such instructions and may conclusively rely on, and shall be
protected in relying on, such instructions. Upon the issuance of Definitive
Certificates all references herein to obligations imposed upon or to be
performed by the Depository shall be deemed to be imposed upon and performed by
the Trustee, to the extent applicable with respect to such Definitive
Certificates,

                                      -107-

<PAGE>

and the Trustee shall recognize the Holders of the Definitive Certificates as
Certificateholders hereunder.

                  SECTION 5.02.             Registration of Transfer and
                                            Exchange of Certificates.

                  (a) The Trustee shall cause to be kept at one of the offices
or agencies to be appointed by the Trustee in accordance with the provisions of
Section 8.11, a Certificate Register for the Certificates in which, subject to
such reasonable regulations as it may prescribe, the Trustee shall provide for
the registration of Certificates and of transfers and exchanges of Certificates
as herein provided.

                  (b) No transfer of any Class CE Certificate, Class P
Certificate or Residual Certificate shall be made unless that transfer is made
pursuant to an effective registration statement under the Securities Act of
1933, as amended (the "1933 Act"), and effective registration or qualification
under applicable state securities laws, or is made in a transaction that does
not require such registration or qualification. In the event that such a
transfer of a Class CE Certificate, Class P Certificate or Residual Certificate
is to be made without registration or qualification (other than in connection
with the initial transfer of any such Certificate by the Depositor to an
affiliate of the Depositor), the Trustee shall require receipt of: (i) if such
transfer is purportedly being made in reliance upon Rule 144A under the 1933
Act, written certifications from the Certificateholder desiring to effect the
transfer and from such Certificateholder's prospective transferee, substantially
in the forms attached hereto as Exhibit F-1; and (ii) in all other cases, an
Opinion of Counsel satisfactory to it that such transfer may be made without
such registration or qualification (which Opinion of Counsel shall not be an
expense of the Trust Fund or of the Depositor, the Trustee, the Master Servicer
in its capacity as such or any Sub-Servicer), together with copies of the
written certification(s) of the Certificateholder desiring to effect the
transfer and/or such Certificateholder's prospective transferee upon which such
Opinion of Counsel is based, if any. None of the Depositor, the Master Servicer
or the Trustee is obligated to register or qualify any such Certificates under
the 1933 Act or any other securities laws or to take any action not otherwise
required under this Agreement to permit the transfer of such Certificates
without registration or qualification. Any Certificateholder desiring to effect
the transfer of any such Certificate shall, and does hereby agree to, indemnify
the Trustee, the Depositor and the Master Servicer 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.

                  (c) No transfer of a Class CE Certificate, Class P Certificate
or Residual Certificate or any interest therein shall be made to any Plan
subject to ERISA or Section 4975 of the Code, any Person acting, directly or
indirectly, on behalf of any such Plan or any Person acquiring such Certificates
with "Plan Assets" of a Plan within the meaning of the Department of Labor
regulation promulgated at 29 C. F. R. ss. 2510.3-101 ("Plan Assets"), as
certified by such transferee in the form of Exhibit G, unless the Depositor, the
Trustee and the Master Servicer are provided with an Opinion of Counsel which
establishes to the satisfaction of the Depositor, the Trustee and the Master
Servicer that the purchase of such Certificates is permissible under applicable
law, will not constitute or result in any prohibited transaction under ERISA or
Section 4975 of the Code and will not subject the Depositor, the Master
Servicer, the NIMS Insurer, the Trustee or the Trust Fund to any obligation or
liability (including obligations or liabilities under ERISA or Section 4975 of
the Code) in addition to those undertaken in this Agreement, which Opinion of
Counsel shall not be an

                                      -108-

<PAGE>

expense of the Depositor, the Master Servicer, the Trustee or the Trust Fund.
Neither an Opinion of Counsel nor any certification will be required in
connection with the initial transfer of any such Certificate by the Depositor to
an affiliate of the Depositor (in which case, the Depositor or any affiliate
thereof shall have deemed to have represented that such affiliate is not a Plan
or a Person investing Plan Assets) and the Trustee shall be entitled to
conclusively rely upon a representation (which, upon the request of the Trustee,
shall be a written representation) from the Depositor of the status of such
transferee as an affiliate of the Depositor.

                  Each beneficial owner of a Mezzanine Certificates or any
interest therein shall be deemed to have represented, by virtue of its
acquisition or holding of that certificate or interest therein, that either (i)
it is not a Plan investor, (ii) it has acquired and is holding such Mezzanine
Certificates in reliance on the Underwriters' Exemption, and that it understands
that there are certain conditions to the availability of the Underwriters'
Exemption, including that the Mezzanine Certificates must be rated, at the time
of purchase, not lower than" BBB-" (or its equivalent) by Fitch, Moody's or S&P
or (iii) (1) it is an insurance company, (2) the source of funds used to acquire
or hold the certificate or interest therein is an "insurance company general
account," as such term is defined in PTCE 95-60, and (3) the conditions in
Sections I and III of PTCE 95-60 have been satisfied.

                  If any Class CE Certificate, Class P Certificate or Residual
Certificate or any interest therein is acquired or held in violation of the
provisions of the preceding paragraph, the next preceding permitted beneficial
owner will be treated as the beneficial owner of that Certificate retroactive to
the date of transfer to the purported beneficial owner. Any purported beneficial
owner whose acquisition or holding of any such Certificate or interest therein
was effected in violation of the provisions of the preceding paragraph shall
indemnify and hold harmless the Depositor, the Master Servicer, the NIMS
Insurer, the Trustee and the Trust Fund from and against any and all
liabilities, claims, costs or expenses incurred by those parties as a result of
that acquisition or holding.

                  (d)(i) Each Person who has or who acquires any Ownership
Interest in a Residual Certificate shall be deemed by the acceptance or
acquisition of such Ownership Interest to have agreed to be bound by the
following provisions and to have irrevocably authorized the Trustee or its
designee under clause (iii)(A) below to deliver payments to a Person other than
such Person and to negotiate the terms of any mandatory sale under clause
(iii)(B) below and to execute all instruments of Transfer and to do all other
things necessary in connection with any such sale. The rights of each Person
acquiring any Ownership Interest in a Residual Certificate are expressly subject
to the following provisions:

                  (A) Each Person holding or acquiring any Ownership Interest in
         a Residual Certificate shall be a Permitted Transferee and shall
         promptly notify the Trustee of any change or impending change in its
         status as a Permitted Transferee.

                  (B) In connection with any proposed Transfer of any Ownership
         Interest in a Residual Certificate, the Trustee shall require delivery
         to it, and shall not register the Transfer of any Residual Certificate
         until its receipt of, an affidavit and agreement (a "Transfer Affidavit
         and Agreement," in the form attached hereto as Exhibit F-2) from the
         proposed

                                      -109-

<PAGE>

         Transferee, in form and substance satisfactory to the Trustee,
         representing and warranting, among other things, that such Transferee
         is a Permitted Transferee, that it is not acquiring its Ownership
         Interest in the Residual Certificate that is the subject of the
         proposed Transfer as a nominee, trustee or agent for any Person that is
         not a Permitted Transferee, that for so long as it retains its
         Ownership Interest in a Residual Certificate, it will endeavor to
         remain a Permitted Transferee, and that it has reviewed the provisions
         of this Section 5.02(d) and agrees to be bound by them.

                  (C) Notwithstanding the delivery of a Transfer Affidavit and
         Agreement by a proposed Transferee under clause (B) above, if a
         Responsible Officer of the Trustee who is assigned to this transaction
         has actual knowledge that the proposed Transferee is not a Permitted
         Transferee, no Transfer of an Ownership Interest in a Residual
         Certificate to such proposed Transferee shall be effected.

                  (D) Each Person holding or acquiring any Ownership Interest in
         a Residual Certificate shall agree (x) to require a Transfer Affidavit
         and Agreement in the form attached hereto as Exhibit F-2 from any other
         Person to whom such Person attempts to transfer its Ownership Interest
         in a Residual Certificate and (y) not to transfer its Ownership
         Interest unless it provides a Transferor Affidavit (in the form
         attached hereto as Exhibit F-2) to the Trustee stating that, among
         other things, it has no actual knowledge that such other Person is not
         a Permitted Transferee.

                  (E) Each Person holding or acquiring an Ownership Interest in
         a Residual Certificate, by purchasing an Ownership Interest in such
         Certificate, agrees to give the Trustee written notice that it is a
         "pass-through interest holder" within the meaning of temporary Treasury
         regulation Section 1.67-3T(a)(2)(i)(A) immediately upon acquiring an
         Ownership Interest in a Residual Certificate, if it is, or is holding
         an Ownership Interest in a Residual Certificate on behalf of, a
         "pass-through interest holder."

                  (ii) The Trustee will register the Transfer of any Residual
Certificate only if it shall have received the Transfer Affidavit and Agreement
and all of such other documents as shall have been reasonably required by the
Trustee as a condition to such registration. In addition, no Transfer of a
Residual Certificate shall be made unless the Trustee shall have received a
representation letter from the Transferee of such Certificate to the effect that
such Transferee is a Permitted Transferee.

                  (iii)(A) If any purported Transferee shall become a Holder of
         a Residual Certificate in violation of the provisions of this Section
         5.02(d), then the last preceding Permitted Transferee shall be
         restored, to the extent permitted by law, to all rights as holder
         thereof retroactive to the date of registration of such Transfer of
         such Residual Certificate. The Trustee shall be under no liability to
         any Person for any registration of Transfer of a Residual Certificate
         that is in fact not permitted by this Section 5.02(d) or for making any
         payments due on such Certificate to the holder thereof or for taking
         any other action with respect to such holder under the provisions of
         this Agreement.

                                      -110-

<PAGE>

                  (B) If any purported Transferee shall become a holder of a
         Residual Certificate in violation of the restrictions in this Section
         5.02(d) and to the extent that the retroactive restoration of the
         rights of the holder of such Residual Certificate as described in
         clause (iii)(A) above shall be invalid, illegal or unenforceable, then
         the Trustee shall have the right, without notice to the holder or any
         prior holder of such Residual Certificate, to sell such Residual
         Certificate to a purchaser selected by the Trustee on such terms as the
         Trustee may choose. Such purported Transferee shall promptly endorse
         and deliver each Residual Certificate in accordance with the
         instructions of the Trustee. Such purchaser may be the Trustee itself
         or any Affiliate of the Trustee. The proceeds of such sale, net of the
         commissions (which may include commissions payable to the Trustee or
         its Affiliates), expenses and taxes due, if any, will be remitted by
         the Trustee to such purported Transferee. The terms and conditions of
         any sale under this clause (iii)(B) shall be determined in the sole
         discretion of the Trustee, and the Trustee shall not be liable to any
         Person having an Ownership Interest in a Residual Certificate as a
         result of its exercise of such discretion.

                  (iv) The Trustee shall make available to the Internal Revenue
Service and those Persons specified by the REMIC Provisions all information
necessary to compute any tax imposed (A) as a result of the Transfer of an
Ownership Interest in a Residual Certificate to any Person who is a Disqualified
Organization, including the information described in Treasury regulations
sections 1.860D-1(b)(5) and 1.860E-2(a)(5) with respect to the "excess
inclusions" of such Residual Certificate and (B) as a result of any regulated
investment company, real estate investment trust, common Trust, partnership,
trust, estate or organization described in Section 1381 of the Code that holds
an Ownership Interest in a Residual Certificate having as among its record
holders at any time any Person which is a Disqualified Organization. Reasonable
compensation for providing such information may be accepted by the Trustee.

                  (v) The provisions of this Section 5.02(d) set forth prior to
this subsection (v) may be modified, added to or eliminated, provided that there
shall have been delivered to the Trustee and the NIMS Insurer at the expense of
the party seeking to modify, add to or eliminate any such provision the
following:

                  (A) written notification from each Rating Agency to the effect
         that the modification, addition to or elimination of such provisions
         will not cause such Rating Agency to downgrade its then-current ratings
         of any Class of Certificates; and

                  (B) an Opinion of Counsel, in form and substance satisfactory
         to the Trustee and the NIMS Insurer, to the effect that such
         modification of, addition to or elimination of such provisions will not
         cause any Trust REMIC to cease to qualify as a REMIC and will not cause
         any Trust REMIC to be subject to an entity-level tax caused by the
         Transfer of any Residual Certificate to a Person that is not a
         Permitted Transferee or a Person other than the prospective transferee
         to be subject to a REMIC-tax caused by the Transfer of a Residual
         Certificate to a Person that is not a Permitted Transferee.

                  The Trustee shall forward to the NIMS Insurer a copy of the
items delivered to it pursuant to (A) and (B) above.

                                      -111-

<PAGE>

                  (e) Subject to the preceding subsections, upon surrender for
registration of transfer of any Certificate at any office or agency of the
Trustee maintained for such purpose pursuant to Section 8.11, the Trustee shall
execute, authenticate and deliver, in the name of the designated Transferee or
Transferees, one or more new Certificates of the same Class of a like aggregate
Percentage Interest.

                  (f) At the option of the Holder thereof, any Certificate may
be exchanged for other Certificates of the same Class with authorized
denominations and a like aggregate Percentage Interest, upon surrender of such
Certificate to be exchanged at any office or agency of the Trustee maintained
for such purpose pursuant to Section 8.11. Whenever any Certificates are so
surrendered for exchange, the Trustee shall execute, authenticate 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 Trustee) be duly endorsed by, or be accompanied by
a written instrument of transfer in the form satisfactory to the Trustee duly
executed by, the Holder thereof or his attorney duly authorized in writing.

                  (g) No service charge to the Certificateholders shall be made
for any transfer or exchange of Certificates, but the Trustee 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.

                  (h) All Certificates surrendered for transfer and exchange
shall be canceled and destroyed by the Trustee in accordance with its customary
procedures.

                  SECTION 5.03.             Mutilated, Destroyed, Lost or Stolen
                                            Certificates.

                  If (i) any mutilated Certificate is surrendered to the
Trustee, or the Trustee receives evidence to its satisfaction of the
destruction, loss or theft of any Certificate, and (ii) there is delivered to
the Trustee and the NIMS Insurer such security or indemnity as may be required
by it to save it harmless, then, in the absence of actual knowledge by the
Trustee that such Certificate has been acquired by a bona fide purchaser or the
Trustee shall execute, authenticate and deliver, in exchange for or in lieu of
any such mutilated, destroyed, lost or stolen Certificate, a new Certificate of
the same Class and of like denomination and Percentage Interest. Upon the
issuance of any new Certificate under this Section, the Trustee 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 expenses (including the fees
and expenses of the Trustee) connected therewith. Any replacement Certificate
issued pursuant to this Section shall constitute complete and indefeasible
evidence of ownership in the applicable REMIC created hereunder, 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.

                  The Depositor, the Master Servicer, the NIMS Insurer, the
Trustee and any agent of any of them 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

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<PAGE>

purposes whatsoever, and none of the Depositor, the Master Servicer, the NIMS
Insurer, the Trustee or any agent of any of them shall be affected by notice to
the contrary.

                  SECTION 5.05.             Certain Available Information.

                  On or prior to the date of the first sale of any Class CE
Certificate, Class P Certificate or Residual Certificate to an Independent third
party, the Depositor shall provide to the Trustee ten copies of any private
placement memorandum or other disclosure document used by the Depositor in
connection with the offer and sale of such Certificates. In addition, if any
such private placement memorandum or disclosure document is revised, amended or
supplemented at any time following the delivery thereof to the Trustee, the
Depositor promptly shall inform the Trustee of such event and shall deliver to
the Trustee ten copies of the private placement memorandum or disclosure
document, as revised, amended or supplemented. The Trustee shall maintain at its
Corporate Trust Office and shall make available free of charge during normal
business hours for review by any Holder of a Certificate or any Person
identified to the Trustee as a prospective transferee of a Certificate,
originals or copies of the following items: (i) in the case of a Holder or
prospective transferee of a Class CE Certificate, Class P Certificate or
Residual Certificate, the related private placement memorandum or other
disclosure document relating to such Class of Certificates, in the form most
recently provided to the Trustee; and (ii) in all cases, (A) this Agreement and
any amendments hereof entered into pursuant to Section 11.01, (B) all monthly
statements required to be delivered to Certificateholders of the relevant Class
pursuant to Section 4.02 since the Closing Date, and all other notices, reports,
statements and written communications delivered to the Certificateholders of the
relevant Class pursuant to this Agreement since the Closing Date, (C) all
certifications delivered by a Responsible Officer of the Trustee since the
Closing Date pursuant to Section 10.01(h), (D) any and all Officers'
Certificates delivered to the Trustee by the Master Servicer since the Closing
Date to evidence the Master Servicer's determination that any P& I Advance or
Servicing Advance was, or if made, would be a Nonrecoverable Advance or
Nonrecoverable Servicing Advance, respectively, and (E) any and all Officers'
Certificates delivered to the Trustee by the Master Servicer since the Closing
Date pursuant to Section 4.04(a). Copies and mailing of any and all of the
foregoing items will be available from the Trustee upon request at the expense
of the Person requesting the same.

                                      -113-

<PAGE>

                                   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 each shall be liable in
accordance herewith only to the extent of the obligations specifically imposed
by this Agreement upon them in their respective capacities as Depositor and
Master Servicer and undertaken hereunder by the Depositor and the Master
Servicer herein.

                  SECTION 6.02.             Merger or Consolidation of the
                                            Depositor or the Master Servicer.

                  Subject to the following paragraph, the Depositor will keep in
full effect its existence, rights and franchises as a corporation under the laws
of the jurisdiction of its incorporation. Subject to the following paragraph,
the Master Servicer will keep in full effect its existence, rights and
franchises as a corporation under the laws of the jurisdiction of its
incorporation. The Depositor and the Master Servicer each 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.

                  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 the Master Servicer shall be a party, or
any Person succeeding to the business of the Depositor or the Master Servicer,
shall be the successor of the Depositor or the Master Servicer, as the case may
be, 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 the successor or surviving Person to
the Master Servicer shall be qualified to service mortgage loans on behalf of
Fannie Mae or Freddie Mac; and provided further that the Rating Agencies'
ratings of the Class A Certificates, the Class S Certificates and the Mezzanine
Certificates in effect immediately prior to such merger or consolidation will
not be qualified, reduced or withdrawn as a result thereof (as evidenced by a
letter to such effect from the Rating Agencies).

                  SECTION 6.03.             Limitation on Liability of the
                                            Depositor, the Master Servicer and
                                            Others.

                  (a) The Master Servicer (except the Trustee if it is required
to succeed the Master Servicer hereunder) indemnifies and holds the NIMS Insurer
and each Certificateholder harmless against any and all claims, losses,
penalties, fines, forfeitures, reasonable legal fees and related costs,
judgments, and any other costs, fees and expenses that the NIMS Insurer and any
Certificateholder may sustain in any way related to the failure of the Master
Servicer to perform its duties and service the Mortgage Loans in compliance with
the terms of this Agreement. The Master Servicer shall immediately notify the
NIMS Insurer and each Certificateholder if a claim is made that may result

                                      -114-

<PAGE>

in such claims, losses, penalties, fines, forfeitures, legal fees or related
costs, judgments, or any other costs, fees and expenses, and the Master Servicer
shall assume (with the consent of the Trustee) the defense of any such claim and
pay all expenses in connection therewith, including reasonable counsel fees, and
promptly pay, discharge and satisfy any judgment or decree which may be entered
against the NIMS Insurer and/or the Certificateholder in respect of such claim.
The provisions of this Section 6.03 shall survive the termination of this
Agreement and the payment of the outstanding Certificates.

                  (b) None of the Depositor, the NIMS Insurer, the Master
Servicer or any of the directors, officers, employees or agents of the Depositor
or the Master Servicer shall be under any liability to the Trust Fund or the
Certificateholders 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 the Depositor, the
Master Servicer or any such person against any breach of warranties,
representations or covenants made herein, or against any specific liability
imposed on the Master Servicer pursuant hereto, 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 or a breach of a representation or warranty
hereunder or, in the case of the Master Servicer, a breach of the servicing
standard set forth in Section 3.01. The Depositor, the NIMS Insurer and the
Master Servicer and any director, officer, employee or agent of the Depositor,
the NIMS Insurer or the Master Servicer 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. The Depositor, the NIMS Insurer, the
Master Servicer and any director, officer, employee or agent of the Depositor,
the NIMS Insurer or the Master Servicer shall be indemnified and held harmless
by the Trust Fund against any loss, liability or expense incurred in connection
with any legal action relating to this Agreement or the Certificates, other than
any loss, liability or expense relating to any specific Mortgage Loan or
Mortgage Loans (except as any such loss, liability or expense shall be otherwise
reimbursable pursuant to this Agreement) or any loss, liability or expense
incurred by reason of willful misfeasance, bad faith or gross negligence in the
performance of duties hereunder or by reason of reckless disregard of
obligations and duties hereunder. Neither the Depositor, the NIMS Insurer 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 each of the Depositor, the NIMS Insurer and
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. In such event, unless the Depositor or the Master Servicer acts
without the consent of Holders of Certificates entitled to at least 51% of the
Voting Rights, the legal expenses and costs of such action and any liability
resulting therefrom (except any loss, liability or expense incurred by reason of
willful misfeasance, bad faith or gross negligence in the performance of duties
hereunder or by reason of reckless disregard of obligations and duties
hereunder) shall be expenses, costs and liabilities of the Trust Fund, and the
Depositor, the NIMS Insurer and the Master Servicer shall be entitled to be
reimbursed therefor from the Collection Account as and to the extent provided in
Section 3.11, any such right of reimbursement being prior to the rights of the
Certificateholders to receive any amount in the Collection Account.

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<PAGE>

                  SECTION 6.04.             Limitation on Resignation of the
                                            Master Servicer.

                  The Master Servicer shall not resign from the obligations and
duties hereby imposed on it except upon determination that its duties hereunder
are no longer permissible under applicable law. Any such determination pursuant
to the preceding sentence permitting the resignation of the Master Servicer
shall be evidenced by an Opinion of Counsel to such effect obtained at the
expense of the Master Servicer and delivered to the Trustee and the NIMS
Insurer. No resignation of the Master Servicer shall become effective until the
Trustee or a successor servicer acceptable to the NIMS Insurer shall have
assumed the Master Servicer's responsibilities, duties, liabilities (other than
those liabilities arising prior to the appointment of such successor) and
obligations under this Agreement. Any such resignation shall not relieve the
Master Servicer of responsibility for any of the obligations specified in
Sections 7.01 and 7.02 as obligations that survive the resignation or
termination of the Master Servicer.

                  Except as expressly provided herein, the Master Servicer shall
not assign or transfer any of its rights, benefits or privileges hereunder 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 hereunder. The foregoing prohibition on
assignment shall not prohibit the Master Servicer from designating a
Sub-Servicer as payee of any indemnification amount payable to the Master
Servicer hereunder; provided, however, that as provided in Section 3.06 hereof,
no Sub-Servicer shall be a third-party beneficiary hereunder and the parties
hereto shall not be required to recognize any Sub-Servicer as an indemnitee
under this Agreement. If, pursuant to any provision hereof, the duties of the
Master Servicer are transferred to a successor master servicer, the entire
amount of the Servicing Fee and other compensation payable to the Master
Servicer pursuant hereto shall thereafter be payable to such successor master
servicer.

                  SECTION 6.05.             Rights of the Depositor in Respect
                                            of the Master Servicer.

                  The Master Servicer shall afford (and any Sub-Servicing
Agreement shall provide that each Sub-Servicer shall afford) the Depositor, the
NIMS Insurer and the Trustee, upon reasonable notice, during normal business
hours, access to all records maintained by the Master Servicer (and any such
Sub-Servicer) in respect of the Master Servicer's rights and obligations
hereunder and access to officers of the Master Servicer (and those of any such
Sub-Servicer) responsible for such obligations. Upon request, the Master
Servicer shall furnish to the Depositor, the NIMS Insurer and the Trustee its
(and any such Sub-Servicer's) most recent financial statements and such other
information relating to the Master Servicer's capacity to perform its
obligations under this Agreement as it possesses (and that any such Sub-Servicer
possesses). To the extent such information is not otherwise available to the
public, the Depositor, the NIMS Insurer and the Trustee shall not disseminate
any information obtained pursuant to the preceding two sentences without the
Master Servicer's written consent, except as required pursuant to this Agreement
or to the extent that it is appropriate to do so (i) in working with legal
counsel, auditors, taxing authorities or other governmental agencies or (ii)
pursuant to any law, rule, regulation, order, judgment, writ, injunction or
decree of any court or governmental authority having jurisdiction over the
Depositor and the Trustee or the Trust Fund, and in any case, the Depositor, the
NIMS Insurer or the Trustee as the case may be, shall use its best efforts to
assure the confidentiality of any such disseminated non-public information. The
Depositor may, but is not obligated to, enforce the obligations of the Master

                                      -116-

<PAGE>

Servicer under this Agreement and may, but is not obligated to, perform, or
cause a designee to perform, any defaulted obligation of the Master Servicer
under this Agreement or exercise the rights of the Master Servicer under this
Agreement; provided that the Master Servicer shall not be relieved of any of its
obligations under this Agreement by virtue of such performance by the Depositor
or its designee. The Depositor shall not have any responsibility or liability
for any action or failure to act by the Master Servicer and is not obligated to
supervise the performance of the Master Servicer under this Agreement or
otherwise.

                                      -117-

<PAGE>

                                   ARTICLE VII

                                     DEFAULT

                  SECTION 7.01.             Master Servicer Events of Default.

         (a) "Master Servicer Event of Default," wherever used herein, means any
one of the following events:

                  (i) any failure by the Master Servicer to remit to the Trustee
         for distribution to the Certificateholders any payment (other than an
         Advance required to be made from its own funds on any Master Servicer
         Remittance Date pursuant to Section 4.03) required to be made under the
         terms of the Certificates and this Agreement which continues unremedied
         for a period of one Business Day 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 Depositor or the Trustee (in
         which case notice shall be provided by telecopy), or to the Master
         Servicer, the Depositor and the Trustee by the NIMS Insurer or the
         Holders of Certificates entitled to at least 25% of the Voting Rights;
         or

                  (ii) 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 contained in this
         Agreement, or the breach by the Master Servicer of any representation
         and warranty contained in Section 2.05, which continues unremedied for
         a period of 30 days (or if such failure or breach cannot be remedied
         within 30 days, then such remedy shall have been commenced within 30
         days and diligently pursued thereafter; provided, however, that in no
         event shall such failure or breach be allowed to exist for a period of
         greater than 90 days) after the earlier of (i) 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 Depositor, the
         Trustee or to the Master Servicer, the Depositor and the Trustee by the
         NIMS Insurer or the Holders of Certificates entitled to at least 25% of
         the Voting Rights and (ii) actual knowledge of such failure by a
         Servicing Officer of the Master Servicer; or

                  (iii) a decree or order of a court or agency or supervisory
         authority having jurisdiction in the premises in an involuntary case
         under any present or future federal or state bankruptcy, insolvency or
         similar law or the appointment of a conservator or receiver or
         liquidator in any insolvency, readjustment of debt, marshalling of
         assets and liabilities or similar proceeding, 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 or unstayed for a period of 90 days; or

                  (iv) the Master Servicer shall consent to the appointment of a
         conservator or receiver or liquidator in any insolvency, readjustment
         of debt, marshalling of assets and liabilities or similar proceedings
         of or relating to it or of or relating to all or substantially all of
         its property; or

                                      -118-

<PAGE>

                  (v) 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 or reorganization statute, make
         an assignment for the benefit of its creditors, or voluntarily suspend
         payment of its obligations; or

                  (vi) any failure by the Master Servicer of the Delinquency
         Master Servicer Termination Trigger; or

                  (vii) any failure of the Master Servicer to make any Advance
         on any Master Servicer Remittance Date required to be made from its own
         funds pursuant to Section 4.03 which continues unremedied until 5:00
         p.m. New York time on such Master Servicer Remittance Date.

                  If a Master Servicer Event of Default described in clauses (i)
through (vi) of this Section shall occur, then, and in each and every such case,
so long as such Master Servicer Event of Default shall not have been remedied,
the Depositor or the Trustee may, and at the written direction of the Holders of
Certificates entitled to at least 51% of Voting Rights or the NIMS Insurer, the
Trustee shall, by notice in writing to the Master Servicer (and to the Depositor
if given by the Trustee or to the Trustee if given by the Depositor), terminate
all of the rights and obligations of the Master Servicer in its capacity as
Master Servicer under this Agreement, to the extent permitted by law, and in and
to the Mortgage Loans and the proceeds thereof. If a Master Servicer Event of
Default described in clause (vii) hereof shall occur, the Trustee shall, by
notice in writing to the Master Servicer, the Depositor and the NIMS Insurer,
terminate all of the rights and obligations of the Master Servicer in its
capacity as Master Servicer under this Agreement and in and to the Mortgage
Loans and the proceeds thereof. On or after the 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 (other than as a Holder
of any Certificate) or the Mortgage Loans or otherwise, shall pass to and be
vested in the Trustee pursuant to and under this Section, and, without
limitation, the Trustee is hereby authorized and empowered, as attorney-in-fact
or otherwise, to execute and deliver, on behalf of and at the expense of the
Master Servicer, 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 promptly (and in any event no later
than ten Business Days subsequent to such notice) provide the Trustee with all
documents and records requested by it to enable it to assume the Master
Servicer's functions under this Agreement, and to cooperate with the Trustee in
effecting the termination of the Master Servicer's responsibilities and rights
under this Agreement, including, without limitation, the transfer within one
Business Day to the Trustee for administration by it of all cash amounts which
at the time shall be or should have been credited by the Master Servicer to the
Collection Account held by or on behalf of the Master Servicer, the Distribution
Account or any REO Account or Servicing Account held by or on behalf of the
Master Servicer or thereafter be received with respect to the Mortgage Loans or
any REO Property serviced by the Master Servicer (provided, however, that the
Master Servicer shall continue to be entitled to receive all amounts accrued or
owing to it under this Agreement on or prior to the date of such termination,
whether in respect of Advances or otherwise, and shall continue to be entitled
to the benefits of Section 6.03, notwithstanding any such termination, with
respect to events occurring prior to such termination).

                                      -119-

<PAGE>

For purposes of this Section 7.01, the Trustee shall not be deemed to have
knowledge of a Master Servicer Event of Default unless a Responsible Officer of
the Trustee assigned to and working in the Trustee's Corporate Trust Office has
actual knowledge thereof or unless written notice of any event which is in fact
such a Master Servicer Event of Default is received by the Trustee and such
notice references the Certificates, the Trust Fund or this Agreement.

                  SECTION 7.02.             Trustee to Act; Appointment of
                                            Successor.

                  (a)(1) From the time the Master Servicer (and the Trustee, if
notice is sent by the Holders of Certificates entitled to at least 51% of Voting
Rights or the NIMS Insurer) receives a notice of termination, the Trustee (or
such other successor Master Servicer as is acceptable to the NIMS Insurer) 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 all the responsibilities, duties and liabilities relating
thereto and arising thereafter shall be assumed by the Trustee (except for any
representations or warranties of the Master Servicer under this Agreement, the
responsibilities, duties and liabilities contained in Section 2.05 (other than
with respect to Section 2.05(x)) and the obligation to deposit amounts in
respect of losses pursuant to Section 3.12) by the terms and provisions hereof;
provided, however, the Trustee shall immediately assume the Master Servicer's
obligations to make Advances pursuant to Section 4.03; provided, further,
however, that if the Trustee is prohibited by law or regulation from obligating
itself to make advances regarding delinquent mortgage loans, then the Trustee
shall not be obligated to make Advances pursuant to Section 4.03; and provided
further, that any failure to perform such duties or responsibilities caused by
the Master Servicer's failure to provide information required by Section 7.01
shall not be considered a default by the Trustee as successor to the Master
Servicer hereunder. It is understood and acknowledged by the parties hereto that
there will be a period of transition (not to exceed 90 days) before the
transition of servicing obligations is fully effective. As compensation
therefor, the Trustee shall be entitled to the Servicing Fee and all funds
relating to the Mortgage Loans to which the Master Servicer would have been
entitled if it had continued to act hereunder. Notwithstanding the above and
subject to Section 7.02(a)(2) below, the Trustee if it shall be unwilling to so
act, or shall, if it is unable to so act or if it is prohibited by law from
making advances regarding delinquent mortgage loans or if the Holders of
Certificates entitled to at least 51% of the Voting Rights or the NIMS Insurer
so request in writing to the Trustee, promptly appoint or petition a court of
competent jurisdiction to appoint, an established mortgage loan servicing
institution acceptable to each Rating Agency and the NIMS Insurer and having a
net worth of not less than $15,000,000, as the successor to the Master Servicer
under this Agreement in the assumption of all or any part of the
responsibilities, duties or liabilities of the Master Servicer under this
Agreement.

                  Pending appointment of a successor to the Master Servicer
hereunder, unless the Trustee is prohibited by law from so acting, the Trustee
shall act in such capacity as hereinabove provided. In connection with such
appointment and assumption, the successor shall be entitled to receive
compensation out of payments on Mortgage Loans in an amount equal to the
compensation which the Master Servicer would otherwise have received pursuant to
Section 3.18 (or such other compensation as the Trustee and such successor shall
agree, not to exceed the Servicing Fee). The appointment of a successor Master
Servicer shall not affect any liability of the predecessor Master Servicer which
may have arisen under this Agreement prior to its termination as Master Servicer
to pay any deductible under an insurance policy pursuant to Section 3.14 or to
indemnify the NIMS

                                      -120-

<PAGE>

Insurer pursuant to Section 6.03), nor shall any successor Master Servicer be
liable for any acts or omissions of the predecessor Master Servicer or for any
breach by such Master Servicer of any of its representations or warranties
contained herein or in any related document or agreement. The Trustee and such
successor shall take such action, consistent with this Agreement, as shall be
necessary to effectuate any such succession. All Servicing Transfer Costs shall
be paid by the predecessor Master Servicer upon presentation of reasonable
documentation of such costs, and if such predecessor Master Servicer defaults in
its obligation to pay such costs, such costs shall be paid by the successor
Master Servicer or the Trustee (in which case the successor Master Servicer or
the Trustee, as applicable, shall be entitled to reimbursement therefor from the
assets of the Trust Fund pursuant to Section 3.11(b)).

                  (2) No appointment of a successor to the Master Servicer under
this Agreement shall be effective until the assumption by the successor of all
of the Master Servicer's responsibilities, duties and liabilities hereunder. In
connection with such appointment and assumption described herein, the Trustee
may make such arrangements for the compensation of such successor out of
payments on Mortgage Loans as it and such successor shall agree; provided,
however, that no such compensation shall be in excess of that permitted the
Master Servicer as such hereunder. The Depositor, the Trustee and such successor
shall take such action, consistent with this Agreement, as shall be necessary to
effectuate any such succession. Pending appointment of a successor to the Master
Servicer under this Agreement or the Trustee shall act in such capacity as
hereinabove provided.

                  Any successor to the Master Servicer, including the Trustee,
shall during the term of its service as servicer continue to service and
administer the Mortgage Loans for the benefit of Certificateholders, and
maintain in force a policy or policies of insurance covering errors and
omissions in the performance of its obligations as Master Servicer hereunder and
a Fidelity Bond in respect of its officers, employees and agents to the same
extent as the Master Servicer is so required pursuant to Section 3.14.

                  (b)      [Reserved]

                  SECTION 7.03.             Notification to Certificateholders.

                  (a) Upon any termination of the Master Servicer pursuant to
Section 7.01 above or any appointment of a successor to the Master Servicer
pursuant to Section 7.02 above, the Trustee shall give prompt written notice
thereof to Certificateholders and the NIMS Insurer at their respective addresses
appearing in the Certificate Register.

                  (b) Not later than the later of 60 days after the occurrence
of any event, which constitutes or which, with notice or lapse of time or both,
would constitute a Master Servicer Event of Default or five days after a
Responsible Officer of the Trustee becomes aware of the occurrence of such an
event, the Trustee shall transmit by mail to the NIMS Insurer and to all Holders
of Certificates notice of each such occurrence, unless such default or Master
Servicer Event of Default shall have been cured or waived.

                  SECTION 7.04.             Waiver of Master Servicer Events of
                                            Default.

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<PAGE>

                  The Holders representing at least 66% of the Voting Rights
(with the consent of the NIMS Insurer) evidenced by all Classes of Certificates
affected by any default or Master Servicer Event of Default hereunder may waive
such default or Master Servicer Event of Default; provided, however, that a
default or Master Servicer Event of Default under clause (i) or (vii) of Section
7.01 may be waived only by all of the Holders of the Regular Certificates (with
the consent of the NIMS Insurer). Upon any such waiver of a default or Master
Servicer Event of Default, such default or Master Servicer Event of Default
shall cease to exist and shall be deemed to have been remedied for every purpose
hereunder. No such waiver shall extend to any subsequent or other default or
Master Servicer Event of Default or impair any right consequent thereon except
to the extent expressly so waived. Notice of any such waiver shall be given by
the Trustee to the Rating Agencies and the NIMS Insurer.

                  SECTION 7.05.             Survivability of Master Servicer
                                            Liabilities.

                  Notwithstanding anything herein to the contrary, upon
termination of the Master Servicer hereunder, any liabilities of the Master
Servicer which accrued prior to such termination shall survive such termination.

                                      -122-

<PAGE>

                                  ARTICLE VIII

                             CONCERNING THE TRUSTEE

                  SECTION 8.01.             Duties of Trustee

                  The Trustee prior to the occurrence of a Master Servicer Event
of Default and after the curing of all Master Servicer Events of Default which
may have occurred, undertakes to perform such duties and only such duties as are
specifically set forth in this Agreement. During a Master Servicer Event of
Default, the Trustee shall exercise such of the rights and powers vested in it
by this Agreement, and use the same degree of care and skill in their exercise
as a prudent person would exercise or use under the circumstances in the conduct
of such person's own affairs. Any permissive right of the Trustee enumerated in
this Agreement shall not be construed as a duty.

                  The Trustee upon receipt of all resolutions, certificates,
statements, opinions, reports, documents, orders or other instruments furnished
to it, which are specifically required to be furnished pursuant to any provision
of this Agreement, shall examine them to determine whether they conform to the
requirements of this Agreement. If any such instrument is found not to conform
to the requirements of this Agreement in a material manner, it shall take such
action as it deems appropriate to have the instrument corrected, and if the
instrument is not corrected to its satisfaction, it will provide notice thereof
to the Certificateholders and the NIMS Insurer.

                  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 misconduct; provided, however, that:

                  (i) Prior to the occurrence of a Master Servicer Event of
         Default, and after the curing of all such Master Servicer 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 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
         that conform to the requirements of this Agreement;

                  (ii) The Trustee shall not be personally liable for an error
         of judgment made in good faith by a Responsible Officer or Responsible
         Officers of it unless it shall be proved that it was negligent in
         ascertaining the pertinent facts; and

                  (iii) 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 the NIMS Insurer or the
         Holders of Certificates entitled to at least 25% of the Voting Rights
         relating to the time, method and place of conducting any proceeding for
         any remedy available to it or exercising any trust or power conferred
         upon it under this Agreement.

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                  SECTION 8.02.             Certain Matters Affecting the
                                            Trustee

                  (a)      Except as otherwise provided in Section 8.01:

                  (i) The Trustee may request and rely upon and shall be
         protected in acting or refraining from acting upon any resolution,
         Officers'Certificate, certificate of auditors or any other certificate,
         statement, instrument, opinion, report, notice, request, consent,
         order, appraisal, bond or other paper or document reasonably believed
         by it to be genuine and to have been signed or presented by the proper
         party or parties;

                  (ii) The Trustee may consult with counsel and 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 Opinion of Counsel;

                  (iii) The Trustee shall not be under any obligation to
         exercise any of the trusts or powers vested in it by this Agreement or
         to institute, conduct or defend any litigation hereunder or in relation
         hereto at the request, order or direction of any of the
         Certificateholders or the NIMS Insurer, pursuant to the provisions of
         this Agreement, unless such Certificateholders or the NIMS Insurer, as
         applicable, shall have offered to the Trustee reasonable security or
         indemnity against the costs, expenses and liabilities which may be
         incurred therein or thereby; nothing contained herein shall, however,
         relieve the Trustee of the obligation, upon the occurrence of a Master
         Servicer Event of Default (which has not been cured or waived), to
         exercise such of the rights and powers vested in it by this Agreement,
         and to use the same degree of care and skill in their exercise as a
         prudent person would exercise or use under the circumstances in the
         conduct of such person's own affairs;

                  (iv) 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;

                  (v) Prior to the occurrence of a Master Servicer Event of
         Default hereunder and after the curing of all Master Servicer 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, approval, bond or other paper or document, unless
         requested in writing to do so by the NIMS Insurer or the Holders of
         Certificates entitled to at least 25% of the Voting Rights; 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 such Certificateholders, the
         Trustee may require reasonable indemnity against such expense, or
         liability from such Certificateholders or the NIMS Insurer, as
         applicable, as a condition to taking any such action;

                  (vi) 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; and

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<PAGE>

                  (vii) The Trustee shall not be personally liable for any loss
         resulting from the investment of funds held in the Collection Account
         at the direction of the Master Servicer pursuant to Section 3.12.

                  (b) All rights of action under this Agreement or under any of
the Certificates, enforceable by the Trustee, may be enforced by it without the
possession of any of the Certificates, or the production thereof at the trial or
other proceeding relating thereto, and any such suit, action or proceeding
instituted by the Trustee shall be brought in its name for the benefit of all
the Holders of such Certificates, subject to the provisions of this Agreement.

                  (c) The Trustee is hereby directed by the Depositor to execute
and deliver the Cap Contract on behalf of the Trust Fund in the form presented
to it by the Depositor.

                  SECTION 8.03.             Trustee not Liable for Certificates
                                            or Mortgage Loans.

                  The recitals contained herein and in the Certificates (other
than the signature of the Trustee, the authentication of the Trustee on the
Certificates, the acknowledgments of the Trustee contained in Article II and the
representations and warranties of the Trustee in Section 8.12) shall be taken as
the statements of the Depositor and the Trustee shall not assume any
responsibility for their correctness. The Trustee shall not make any
representations or warranties as to the validity or sufficiency of this
Agreement (other than as specifically set forth in Section 8.12) or of the
Certificates (other than the signature of the Trustee, and authentication of the
Trustee on the Certificates) or of any Mortgage Loan or related document. 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 Depositor or the Master Servicer in
respect of the Mortgage Loans or deposited in or withdrawn from the Collection
Account by the Master Servicer, other than any funds held by or on behalf of the
Trustee in accordance with Section 3.10.

                  SECTION 8.04.             Trustee May Own Certificates.

                  The Trustee in its individual capacity or any other capacity
may become the owner or pledgee of Certificates with the same rights it would
have if it were not the Trustee.

                  SECTION 8.05.             Trustee's Fees and Expenses.

                  The Trustee shall be entitled to withdraw from the
Distribution Account, pursuant to Section 3.11(b), on each Distribution Date and
pay to itself the Trustee Fee. The Trustee and any director, officer, employee
or agent of the Trustee, shall be indemnified by the Trust Fund and held
harmless against any loss, liability or expense (not including expenses,
disbursements and advances incurred or made by the Trustee including the
compensation and the expenses and disbursements of its agents and counsel, in
the ordinary course of the Trustee's performance in accordance with the
provisions of this Agreement) incurred by the Trustee arising out of or in
connection with the acceptance or administration of its obligations and duties
under this Agreement up to a limit of $600,000 per calender year, other than any
loss, liability or expense (i) resulting from any breach of the Master
Servicer's obligations in connection with this Agreement, (ii) that constitutes
a specific

                                     -125-

<PAGE>

liability of the Trustee pursuant to Section 10.01(g) or (iii) any loss,
liability or expense incurred by reason of willful misfeasance, bad faith or
negligence in the performance of duties hereunder or by reason of reckless
disregard of obligations and duties hereunder as a result of a breach of the
Trustee's obligations under Article X hereof. The Master Servicer agrees to
indemnify the Trustee, from, and hold it harmless against, any loss, liability
or expense arising in respect of any breach by the Master Servicer of its
obligations in connection with this Agreement. Such indemnity shall survive the
termination or discharge of this Agreement and the resignation or removal of the
Trustee. Any payment hereunder made by the Master Servicer to the Trustee shall
be from the Master Servicer's own funds, without reimbursement from REMIC I
therefor. Notwithstanding anything herein to the contrary, the Trustee shall be
reimbursed from the Trust Fund for all Servicing Transfer Costs without regard
to the annual limitation.

                  SECTION 8.06.             Eligibility Requirements for Trustee

                  The Trustee hereunder shall at all times be a corporation or
an association (other than the Depositor, the Originator, the Seller, the Master
Servicer or any Affiliate of the foregoing) organized and doing business under
the laws of any 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 a member of a bank holding company whose capital and
surplus is at least $50,000,000) and subject to supervision or examination by
federal or state authority. If such corporation or association publishes reports
of conditions 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 conditions 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 8.07.

                  SECTION 8.07.             Resignation and Removal of the
                                            Trustee

                  The Trustee may at any time resign and be discharged from the
trust hereby created by giving written notice thereof to the Depositor, the NIMS
Insurer, the Master Servicer and to the Certificateholders. Upon receiving such
notice of resignation, the Depositor shall promptly appoint a successor trustee
acceptable to the NIMS Insurer by written instrument, in duplicate, which
instrument shall be delivered to the resigning Trustee and to the successor
trustee. A copy of such instrument shall be delivered to the Certificateholders,
the Trustee and the Master Servicer by the Depositor. If no successor trustee
shall have been so 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 8.06 and shall fail to resign after
written request therefor by the Depositor or the NIMS Insurer, or if at any time
the Trustee shall become incapable of acting, or shall be adjudged bankrupt or
insolvent, or a receiver of the Trustee or of its property shall be appointed,
or any public officer shall take charge or control of the Trustee or of its
property or affairs for the purpose of rehabilitation, conservation or
liquidation, then the Depositor or the NIMS Insurer may remove the

                                      -126-

<PAGE>

and appoint a successor trustee acceptable to the NIMS Insurer by written
instrument, in duplicate, which instrument shall be delivered to the Trustee so
removed and to the successor trustee. A copy of such instrument shall be
delivered to the Certificateholders, the Trustee and the Master Servicer by the
Depositor.

                  The Holders of Certificates entitled to at least 51% of the
Voting Rights (or the NIMS Insurer upon failure of the Trustee to perform its
obligations hereunder) may at any time remove the Trustee and appoint a
successor trustee acceptable to the NIMS Insurer 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
Depositor, one complete set to the Trustee so removed and one complete set to
the successor so appointed. A copy of such instrument shall be delivered to the
Certificateholders and the Master Servicer by the Depositor.

                  Any resignation or removal of the Trustee and appointment of a
successor trustee, pursuant to any of the provisions of this Section shall not
become effective until acceptance of appointment by the successor trustee as
provided in Section 8.08. Notwithstanding the foregoing, in the event the
Trustee is unable to continue to perform its obligations pursuant to the terms
of this Agreement prior to the appointment of a successor, the Trustee shall be
obligated to perform such obligations until a new trustee is appointed. Such
performance shall be without prejudice to any claim by a party hereto or
beneficiary hereof resulting from the Trustee's breach of its obligations
hereunder.

                  SECTION 8.08.             Successor Trustee

                  Any successor trustee appointed as provided in Section 8.07
shall execute, acknowledge and deliver to the Depositor, the NIMS Insurer and
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 trustee, without any further act, deed or
conveyance, shall become fully vested with all the rights, powers, duties and
obligations of its predecessor hereunder, with the like effect as if originally
named as trustee herein. The predecessor trustee shall deliver to the successor
trustee all Mortgage Files and related documents and statements to the extent
held by it hereunder, as well as all moneys, held by it hereunder, and the
Depositor and the predecessor trustee 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.

                  No successor trustee shall accept appointment as provided in
this Section unless at the time of such acceptance such successor trustee shall
be eligible under the provisions of Section 8.06 and the appointment of such
successor trustee shall not result in a downgrading of any Class of Certificates
by any Rating Agency, as evidenced by a letter from each Rating Agency.

                  Upon acceptance of appointment by a successor trustee, as
provided in this Section, the Depositor shall mail notice of the succession of
such trustee hereunder to all Holders of Certificates at their addresses as
shown in the Certificate Register. If the Depositor fails to mail such notice
within 10 days after acceptance of appointment by the successor trustee, the
successor trustee shall cause such notice to be mailed at the expense of the
Depositor.

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<PAGE>

                  SECTION 8.09.             Merger or Consolidation of Trustee.

                  Any corporation or association into which either the Trustee
may be merged or converted or with which it may be consolidated or any
corporation or association resulting from any merger, conversion or
consolidation to which the Trustee shall be a party, or any corporation or
association succeeding to the business of the Trustee shall be the successor of
the Trustee hereunder, provided such corporation or association shall be
eligible under the provisions of Section 8.06, 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.

                  SECTION 8.10.             Appointment of Co-Trustee or
                                            Separate Trustee.

                  Notwithstanding any other provisions hereof, at any time, for
the purpose of meeting any legal requirements of any jurisdiction in which any
part of REMIC I or property securing the same may at the time be located, the
Trustee shall have the power and shall execute and deliver all instruments to
appoint one or more Persons approved by the Trustee and the NIMS Insurer to act
as co-trustee or co-trustees, jointly with the Trustee, or separate trustee or
separate trustees, of all or any part of REMIC I, and to vest in such Person or
Persons, in such capacity, such title to REMIC I, or any part thereof, and,
subject to the other provisions of this Section 8.10, such powers, duties,
obligations, rights and trusts as the Trustee may consider necessary or
desirable. Any such co-trustee or separate trustee shall be subject to the
written approval of the NIMS Insurer. If the NIMS Insurer shall not have joined
in such appointment within 15 days after the receipt by it of a request to do
so, the Trustee alone shall have the power to make such appointment. No
co-trustee or separate trustee hereunder shall be required to meet the terms of
eligibility as a successor trustee under Section 8.06 hereunder and no notice to
Holders of Certificates of the appointment of co-trustee(s) or separate
trustee(s) shall be required under Section 8.08 hereof.

                  In the case of any appointment of a co-trustee or separate
trustee pursuant to this Section 8.10 all 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 by the Trustee (whether as
Trustee hereunder or as successor to a defaulting 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 REMIC I or any portion thereof in any such jurisdiction) shall be
exercised and performed by such separate trustee or co-trustee at the direction
of the Trustee.

                  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 or co-trustee shall refer to this Agreement and
the conditions of this Article VIII. Each separate trustee and co-trustee, upon
its acceptance of the trust 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 filed with the
Trustee and a copy thereof given to the NIMS Insurer.

                                      -128-

<PAGE>

                  Any separate trustee or co-trustee 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 or co-trustee.

                  SECTION 8.11.             Appointment of Office or Agency.

                  The Trustee will appoint an office or agency in the City of
Minneapolis, Minnesota where the Certificates may be surrendered for
registration of transfer or exchange, and presented for final distribution, and
where notices and demands to or upon the Trustee in respect of the Certificates
and this Agreement may be served.

                  SECTION 8.12.             Representations and Warranties.

                  The Trustee hereby represents and warrants to the Master
Servicer and the Depositor, as of the Closing Date, that:

                  (i) It is a national banking association duly organized,
         validly existing and in good standing under the laws of the United
         States of America.

                  (ii) The execution and delivery of this Agreement by it, and
         the performance and compliance with the terms of this Agreement by it,
         will not violate its articles of association or bylaws 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 agreement or other instrument to which it is a party or which
         is applicable to it or any of its assets.

                  (iii) It has the full power and authority to enter into and
         consummate all transactions contemplated by this Agreement, has duly
         authorized the execution, delivery and performance of this Agreement,
         and has duly executed and delivered this Agreement.

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

                  (v) It is not in violation of, and its execution and delivery
         of this Agreement and its performance and compliance with the terms of
         this Agreement will not constitute a violation of, any law, any order
         or decree of any court or arbiter, or any order, regulation or demand
         of any federal, state or local governmental or regulatory authority,
         which violation, in its good faith and reasonable judgment, is likely
         to affect materially and adversely either the ability of it to perform
         its obligations under this Agreement or its financial condition.

                                      -129-

<PAGE>

                  (vi) No litigation is pending or, to the best of its
         knowledge, threatened against it, which would prohibit it from entering
         into this Agreement or, in its good faith reasonable judgment, is
         likely to materially and adversely affect either the ability of it to
         perform its obligations under this Agreement or its financial
         condition.

                                      -130-

<PAGE>

                                   ARTICLE IX

                                   TERMINATION

                  SECTION 9.01.             Termination Upon Repurchase or
                                            Liquidation of All Mortgage Loans.

                  (a) Subject to Section 9.02, the respective obligations and
responsibilities under this Agreement of the Depositor, the Master Servicer and
the Trustee (other than the obligations of the Master Servicer to the Trustee
pursuant to Section 8.05 and of the Master Servicer to make remittances to the
Trustee and the Trustee to make payments in respect of the REMIC I Regular
Interests and the Classes of Certificates as hereinafter set forth) shall
terminate upon payment to the Certificateholders and the deposit of all amounts
held by or on behalf of the Trustee and required hereunder to be so paid or
deposited on the Distribution Date coinciding with or following the earlier to
occur of (i) the purchase by the Terminator (as defined below) of all Mortgage
Loans and each REO Property remaining in REMIC I and (ii) the final payment or
other liquidation (or any advance with respect thereto) of the last Mortgage
Loan or REO Property remaining in REMIC I; 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. Subject to Section 3.10 hereof, the purchase by the Terminator of all
Mortgage Loans and each REO Property remaining in REMIC I shall be at a price
(the "Termination Price") equal to the aggregate fair market value of all of the
assets of REMIC I (as determined by the Terminator and the Trustee, as of the
close of business on the third Business Day next preceding the date upon which
notice of any such termination is furnished to Certificateholders pursuant to
the third paragraph of this Section 9.01) plus accrued and unpaid interest
thereon at the weighted average of the Mortgage Rates through the end of the Due
Period preceding the final Distribution Date plus unreimbursed Servicing
Advances, Advances, any unpaid Servicing Fees allocable to such Mortgage Loans
and REO Properties, any accrued and unpaid Net WAC Rate Carryover Amount;
provided, however, such option may only be exercised if (i) the Termination
Price is sufficient to pay all interest accrued on, as well as amounts necessary
to retire the principal balance of, each class of notes issued pursuant to the
Indenture and any remaining amounts owed to the NIMS Insurer on the date such
option is exercised and (ii) the fair market value of the Mortgage Loans and REO
Properties described above is at least equal to the Principal Balance of the
Mortgage Loans (after giving effect to scheduled payments of principal due
during the related Due Period, to the extent received or advanced, and
unscheduled collections of principal received during the related Prepayment
Period) and the appraised value of the REO Properties.

                  (b) The majority holder of the Class CE Certificates (so long
as such holder is not an affiliate of the Seller) or if such majority holder
fails to exercise such right, the Master Servicer (or if the Master Servicer
fails to exercise such right, the NIMS Insurer) shall have the right (the party
exercising such right, the "Terminator"), to purchase all of the Mortgage Loans
and each REO Property remaining in REMIC I pursuant to clause (i) of the
preceding paragraph no later than the Determination Date in the month
immediately preceding the Distribution Date on which the Certificates will be
retired; provided, however, that the Terminator may elect to purchase all of the
Mortgage Loans and each REO Property remaining in REMIC I pursuant to clause (i)
above only

                                      -131-

<PAGE>

if the aggregate Stated Principal Balance of the Mortgage Loans and each REO
Property remaining in the Trust Fund at the time of such election is reduced to
less than 10% of the aggregate Stated Principal Balance of the Mortgage Loans as
of the Cut-off Date. By acceptance of the Residual Certificates, the Holder of
the Residual Certificates agrees for so long as any notes insured by the NIMS
Insurer and secured by all or a portion of the Class CE, Class P or Class R
Certificates are outstanding, in connection with any termination hereunder, to
assign and transfer any amounts in excess of par, and to the extent received in
respect of such termination, to pay any such amounts to the Holders of the Class
CE Certificates.

                  (c) Notice of the liquidation of the Certificates shall be
given promptly by the Trustee by letter to Certificateholders and the NIMS
Insurer mailed (a) in the event such notice is given in connection with the
purchase of the Mortgage Loans and each REO Property by the Terminator, not
earlier than the 10th day and not later than the 20th day of the month next
preceding the month of the final distribution on the Certificates or (b)
otherwise during the month of such final distribution on or before the
Determination Date in such month, in each case specifying (i) the Distribution
Date upon which the Trust Fund will terminate and the final payment in respect
of the REMIC I Regular Interests and the Certificates will be made upon
presentation and surrender of the related Certificates at the office of the
Trustee therein designated, (ii) the amount of any such final payment, (iii)
that no interest shall accrue in respect of the REMIC I Regular Interests or the
Certificates from and after the Accrual Period relating to the final
Distribution Date therefor and (iv) that the Record Date otherwise applicable to
such Distribution Date is not applicable, payments being made only upon
presentation and surrender of the Certificates at the office of the Trustee. In
the event such notice is given in connection with the purchase of all of the
Mortgage Loans and each REO Property remaining in REMIC I by the Terminator, the
Terminator shall deliver to the Trustee for deposit in the Distribution Account
not later than the last Business Day of the month next preceding the month of
the final distribution on the Certificates an amount in immediately available
funds equal to the Termination Price. The Trustee shall remit to the Master
Servicer from such funds deposited in the Distribution Account (i) any amounts
which the Master Servicer would be permitted to withdraw and retain from the
Collection Account pursuant to Section 3.11 and (ii) any other amounts otherwise
payable by the Trustee to the Master Servicer from amounts on deposit in the
Distribution Account pursuant to the terms of this Agreement, in each case prior
to making any final distributions pursuant to Section 10.01(d) below. Upon
certification to the Trustee by the Terminator of the making of such final
deposit, the Trustee shall promptly release to the Terminator the Mortgage Files
for the remaining Mortgage Loans, and the Trustee shall execute all assignments,
endorsements and other instruments necessary to effectuate such transfer.

                  (d) Upon presentation of the Certificates by the
Certificateholders on the final Distribution Date, the Trustee shall distribute
to each Certificateholder so presenting and surrendering its Certificates the
amount otherwise distributable on such Distribution Date in accordance with
Section 4.01 in respect of the Certificates so presented and surrendered. Any
funds not distributed to any Holder or Holders of Certificates being retired on
such Distribution Date because of the failure of such Holder or Holders to
tender their Certificates shall, on such date, be set aside and held in trust
and credited to the account of the appropriate non-tendering Holder or Holders.
If any Certificates as to which notice has been given pursuant to this Section
9.01 shall not have been surrendered for cancellation within six months after
the time specified in such notice, the Trustee shall mail a second notice to the
remaining non-tendering Certificateholders to surrender

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<PAGE>

their Certificates for cancellation in order to receive the final distribution
with respect thereto. If within one year after the second notice all such
Certificates shall not have been surrendered for cancellation, the Trustee
shall, directly or through an agent, mail a final notice to the remaining
non-tendering Certificateholders concerning surrender of their Certificates. The
costs and expenses of maintaining the funds in trust and of contacting such
Certificateholders shall be paid out of the assets remaining in the Trust Fund.
If within one year after the final notice any such Certificates shall not have
been surrendered for cancellation, the Trustee shall pay to UBS Warburg LLC all
such amounts, and all rights of non-tendering Certificateholders in or to such
amounts shall thereupon cease. No interest shall accrue or be payable to any
Certificateholder on any amount held in trust by the Trustee as a result of such
Certificateholder's failure to surrender its Certificate(s) for final payment
thereof in accordance with this Section 9.01. Any such amounts held in trust by
the Trustee shall be held in an Eligible Account and the Trustee may direct any
depository institution maintaining such account to invest the funds in one or
more Permitted Investments. All income and gain realized from the investment of
funds deposited in such accounts held in trust by the Trustee shall be for the
benefit of the Trustee; provided, however, that the Trustee shall deposit in
such account the amount of any loss of principal incurred in respect of any such
Permitted Investment made with funds in such accounts immediately upon the
realization of such loss.

                  Immediately following the deposit of funds in trust hereunder
in respect of the Certificates, the Trust Fund shall terminate.

                  SECTION 9.02.             Additional Termination Requirements.

                  (a) In the event that the Terminator purchases all the
Mortgage Loans and each REO Property or the final payment on or other
liquidation of the last Mortgage Loan or REO Property remaining in REMIC I
pursuant to Section 9.01, the Trust Fund shall be terminated in accordance with
the following additional requirements:

                  (i) The Trustee shall specify the first day in the 90-day
         liquidation period in a statement attached to each Trust REMIC's final
         Tax Return pursuant to Treasury regulation Section 1.860F-1 and shall
         satisfy all requirements of a qualified liquidation under Section 860F
         of the Code and any regulations thereunder, as evidenced by an Opinion
         of Counsel obtained at the expense of the Terminator;

                  (ii) During such 90-day liquidation period and, at or prior to
         the time of making of the final payment on the Certificates, the
         Trustee shall sell all of the assets of REMIC I to the Terminator for
         cash; and

                  (iii) At the time of the making of the final payment on the
         Certificates, the Trustee shall distribute or credit, or cause to be
         distributed or credited, to the Holders of the Residual Certificates
         all cash on hand in the Trust Fund (other than cash retained to meet
         claims), and the Trust Fund shall terminate at that time.

                  (b) At the expense of the requesting Terminator, the Depositor
shall prepare or cause to be prepared the documentation required in connection
with the adoption of a plan of liquidation of each Trust REMIC pursuant to this
Section 9.02.

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                  (c) By their acceptance of Certificates, the Holders thereof
hereby agree to authorize the Trustee to specify the 90-day liquidation period
for each Trust REMIC, which authorization shall be binding upon all successor
Certificateholders.

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                                    ARTICLE X

                                REMIC PROVISIONS

                  SECTION 10.01.            REMIC Administration.

                  (a) The Trustee shall elect to treat each Trust REMIC as a
REMIC under the Code and, if necessary, under applicable state law. Each such
election will be made by the Trustee on Form 1066 or other appropriate federal
tax or information return or any appropriate state return for the taxable year
ending on the last day of the calendar year in which the Certificates are
issued. For the purposes of the REMIC election in respect of REMIC I, the REMIC
I Regular Interests shall be designated as the Regular Interests in REMIC I and
the Class R-I Interest shall be designated as the Residual Interest in REMIC I.
The Class A Certificates, the Mezzanine Certificates, the Class CE Certificates
and the Class P Certificates shall be designated as the Regular Interests in
REMIC II and the Class R-II Interest shall be designated as the Residual
Interest in REMIC II. The Trustee shall not permit the creation of any
"interests" in any Trust REMIC (within the meaning of Section 860G of the Code)
other than the REMIC I Regular Interests and the interests represented by the
Certificates.

                  (b) The Closing Date is hereby designated as the "Startup Day"
of each Trust REMIC within the meaning of Section 860G(a)(9) of the Code.

                  (c) The Trustee shall be reimbursed for any and all expenses
relating to any tax audit of the Trust Fund (including, but not limited to, any
professional fees or any administrative or judicial proceedings with respect to
any Trust REMIC that involve the Internal Revenue Service or state tax
authorities), including the expense of obtaining any tax related Opinion of
Counsel except as specified herein. The Trustee, as agent for each Trust REMIC's
tax matters person shall (i) act on behalf of the Trust Fund in relation to any
tax matter or controversy involving any Trust REMIC and (ii) represent the Trust
Fund in any administrative or judicial proceeding relating to an examination or
audit by any governmental taxing authority with respect thereto. The holder of
the largest Percentage Interest of the Residual Certificates shall be
designated, in the manner provided under Treasury regulations section
1.860F-4(d) and Treasury regulations section 301.6231(a)(7)-1, as the tax
matters person of the related REMIC created hereunder. By their acceptance
thereof, the holder of the largest Percentage Interest of the Residual
Certificates hereby agrees to irrevocably appoint the Trustee or an Affiliate as
its agent to perform all of the duties of the tax matters person for the Trust
Fund.

                  (d) The Trustee shall prepare, sign and file all of the Tax
Returns (including Form 8811, which must be filed within 30 days following the
Closing Date) in respect of each Trust REMIC. The expenses of preparing and
filing such returns shall be borne by the Trustee without any right of
reimbursement therefor.

                  (e) The Trustee shall perform on behalf of each Trust REMIC
all reporting and other tax compliance duties that are the responsibility of
such REMIC under the Code, the REMIC Provisions or other compliance guidance
issued by the Internal Revenue Service or any state or local taxing authority.
Among its other duties, as required by the Code, the REMIC Provisions or other

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<PAGE>

such compliance guidance, the Trustee shall provide (i) to any Transferor of a
Residual Certificate such information as is necessary for the application of any
tax relating to the transfer of a Residual Certificate to any Person who is not
a Permitted Transferee, (ii) to the Certificateholders such information or
reports as are required by the Code or the REMIC Provisions including reports
relating to interest, original issue discount and market discount or premium
(using the Prepayment Assumption as required) and (iii) to the Internal Revenue
Service the name, title, address and telephone number of the person who will
serve as the representative of each Trust REMIC. The Depositor shall provide or
cause to be provided to the Trustee, within ten (10) days after the Closing
Date, all information or data that the Trustee reasonably determines to be
relevant for tax purposes as to the valuations and issue prices of the
Certificates, including, without limitation, the price, yield, prepayment
assumption and projected cash flow of the Certificates.

                  (f) The Trustee shall take such action and shall cause each
Trust REMIC to take such action as shall be necessary to create or maintain the
status thereof as a REMIC under the REMIC Provisions. The Trustee shall not take
any action or cause the Trust Fund to take any action or fail to take (or fail
to cause to be taken) any action that, under the REMIC Provisions, if taken or
not taken, as the case may be, could (i) endanger the status of any Trust REMIC
as a REMIC or (ii) result in the imposition of a tax upon the Trust Fund
(including but not limited to the tax on prohibited transactions as defined in
Section 860F(a)(2) of the Code and the tax on contributions to a REMIC set forth
in Section 860G(d) of the Code) (either such event, an "Adverse REMIC Event")
unless the Trustee and the NIMS Insurer has received an Opinion of Counsel,
addressed to the Trustee (at the expense of the party seeking to take such
action but in no event at the expense of the Trustee) to the effect that the
contemplated action will not, with respect to any Trust REMIC, endanger such
status or result in the imposition of such a tax, nor shall the Master Servicer
take or fail to take any action (whether or not authorized hereunder) as to
which the Trustee and the NIMS Insurer has advised it in writing that it has
received an Opinion of Counsel to the effect that an Adverse REMIC Event could
occur with respect to such action; provided that the Master Servicer may
conclusively rely on such Opinion of Counsel and shall incur no liability for
its action or failure to act in accordance with such Opinion of Counsel. In
addition, prior to taking any action with respect to any Trust REMIC or the
respective assets of each, or causing any Trust REMIC to take any action, which
is not contemplated under the terms of this Agreement, the Master Servicer will
consult with the Trustee, the NIMS Insurer or its designee, in writing, with
respect to whether such action could cause an Adverse REMIC Event to occur with
respect to any Trust REMIC and the Master Servicer shall not take any such
action or cause any Trust REMIC to take any such action as to which the Trustee
or the NIMS Insurer has advised it in writing that an Adverse REMIC Event could
occur; provided that the Master Servicer may conclusively rely on such writing
and shall incur no liability for its action or failure to act in accordance with
such writing. The Trustee or the NIMS Insurer may consult with counsel to make
such written advice, and the cost of same shall be borne by the party seeking to
take the action not permitted by this Agreement, but in no event shall such cost
be an expense of the Trustee. At all times as may be required by the Code, the
Trustee will ensure that substantially all of the assets of REMIC I will consist
of "qualified mortgages" as defined in Section 860G(a)(3) of the Code and
"permitted investments" as defined in Section 860G(a)(5) of the Code, to the
extent such obligations are within the Trustee's control and not otherwise
inconsistent with the terms of this Agreement.

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<PAGE>

                  (g) In the event that any tax is imposed on "prohibited
transactions" of any REMIC created hereunder as defined in Section 860F(a)(2) of
the Code, on the "net income from foreclosure property" of such REMIC as defined
in Section 860G(c) of the Code, on any contributions to any such REMIC after the
Startup Day therefor pursuant to Section 860G(d) of the Code, or any other tax
is imposed by the Code or any applicable provisions of state or local tax laws,
such tax shall be charged (i) to the Trustee pursuant to Section 10.03 hereof,
if such tax arises out of or results from a breach by the Trustee of any of its
obligations under this Article X, (ii) to the Master Servicer pursuant to
Section 10.03 hereof, if such tax arises out of or results from a breach by the
Master Servicer of any of its obligations under Article III or this Article X,
or (iii) against amounts on deposit in the Distribution Account and shall be
paid by withdrawal therefrom.

                  (h) On or before April 15th of each calendar year, commencing
April 15, 2004, the Trustee shall deliver to each Rating Agency and the NIMS
Insurer an Officer's Certificate of the Trustee stating the Trustee's compliance
with this Article X (without regard to any action taken by any party other than
the Trustee).

                  (i) The Trustee shall, for federal income tax purposes,
maintain books and records with respect to each Trust REMIC on a calendar year
and on an accrual basis.

                  (j) Following the Startup Day, neither the Master Servicer nor
the Trustee shall accept any contributions of assets to any Trust REMIC other
than in connection with any Qualified Substitute Mortgage Loan delivered in
accordance with Section 2.03 unless it shall have received an Opinion of Counsel
to the effect that the inclusion of such assets in the Trust Fund will not cause
the related REMIC to fail to qualify as a REMIC at any time that any
Certificates are outstanding or subject such REMIC to any tax under the REMIC
Provisions or other applicable provisions of federal, state and local law or
ordinances.

                  (k) Neither the Trustee nor the Master Servicer shall enter
into any arrangement by which any Trust REMIC will receive a fee or other
compensation for services nor permit either REMIC to receive any income from
assets other than "qualified mortgages" as defined in Section 860G(a)(3) of the
Code or "permitted investments" as defined in Section 860G(a)(5) of the Code.

                  SECTION 10.02.            Prohibited Transactions and
                                            Activities.

                  None of the Depositor, the Master Servicer or the Trustee
shall sell, dispose of or substitute for any of the Mortgage Loans (except in
connection with (i) the foreclosure of a Mortgage Loan, including but not
limited to, the acquisition or sale of a Mortgaged Property acquired by deed in
lieu of foreclosure, (ii) the bankruptcy of REMIC I, (iii) the termination of
REMIC I pursuant to Article IX of this Agreement, (iv) a substitution pursuant
to Article II of this Agreement or (v) a purchase of Mortgage Loans pursuant to
Article II or III of this Agreement), nor acquire any assets for any Trust REMIC
(other than REO Property acquired in respect of a defaulted Mortgage Loan), nor
sell or dispose of any investments in the Collection Account or the Distribution
Account for gain, nor accept any contributions to any Trust REMIC after the
Closing Date (other than a Qualified Substitute Mortgage Loan delivered in
accordance with Section 2.03), unless it has received an Opinion of Counsel,
addressed to the Trustee and the NIMS Insurer (at the expense of the party
seeking to cause such sale, disposition, substitution, acquisition or
contribution but in no event at

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<PAGE>

the expense of the Trustee) that such sale, disposition, substitution,
acquisition or contribution will not (a) affect adversely the status of any
Trust REMIC as a REMIC or (b) cause any Trust REMIC to be subject to a tax on
"prohibited transactions" or "contributions" pursuant to the REMIC Provisions.

                  SECTION 10.03.            Master Servicer and Trustee
                                            Indemnification.

                  (a) In the event that any Trust REMIC fails to qualify as a
REMIC, loses its status as a REMIC, or incurs federal, state or local taxes as a
result of a prohibited transaction or prohibited contribution under the REMIC
Provisions due to (i) the negligent performance by the Trustee of its duties and
obligations set forth herein or (ii) any state, local or franchise taxes imposed
upon the Trust Fund as a result of the location of the Trustee or any
co-trustee, the Trustee shall indemnify the NIMS Insurer and the Trust Fund
against any and all Losses resulting from such negligence, including, without
limitation, any reasonable attorneys' fees imposed on or incurred as a result of
a breach of the Trustee's or any co-trustee's covenants; provided, however, that
the Trustee shall not be liable for any such Losses attributable to the action
or inaction of the Master Servicer, the Depositor or the Holder of such Residual
Certificate, as applicable, nor for any such Losses resulting from
misinformation provided by the Holder of such Residual Certificate on which the
Trustee has relied. The foregoing shall not be deemed to limit or restrict the
rights and remedies of the Holder of such Residual Certificate now or hereafter
existing at law or in equity. Notwithstanding the foregoing, however, in no
event shall the Trustee have any liability (1) for any action or omission that
is taken in accordance with and in compliance with the express terms of, or
which is expressly permitted by the terms of, this Agreement, (2) for any Losses
other than arising out of a negligent performance by the Trustee of its duties
and obligations set forth herein, and (3) for any special or consequential
damages to Certificateholders (in addition to payment of principal and interest
on the Certificates).

                  (b) In the event that any Trust REMIC fails to qualify as a
REMIC, loses its status as a REMIC, or incurs federal, state or local taxes as a
result of a prohibited transaction or prohibited contribution under the REMIC
Provisions due to (i) the negligent performance by the Master Servicer of its
duties and obligations set forth herein or (ii) any state, local or franchise
taxes imposed upon the Trust Fund as a result of the location of the Master
Servicer or any sub-servicer, the Master Servicer shall indemnify the NIMS
Insurer, the Trustee and the Trust Fund against any and all losses, claims,
damages, liabilities or expenses ("Losses") resulting from such negligence,
including, without limitation, any reasonable attorneys' fees imposed on or
incurred as a result of a breach of the Master Servicer's or any sub-servicer's
covenants; provided, however, that the Master Servicer shall not be liable for
any such Losses attributable to the action or inaction of the Trustee, the
Depositor or the Holder of such Residual Certificate, as applicable, nor for any
such Losses resulting from misinformation provided by the Holder of such
Residual Certificate on which the Master Servicer has relied. The foregoing
shall not be deemed to limit or restrict the rights and remedies of the Holder
of such Residual Certificate now or hereafter existing at law or in equity.
Notwithstanding the foregoing, however, in no event shall the Master Servicer
have any liability (1) for any action or omission that is taken in accordance
with and in compliance with the express terms of, or which is expressly
permitted by the terms of, this Agreement, (2) for any Losses other than arising
out of a negligent performance by the Master Servicer of its duties and
obligations set forth

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<PAGE>

herein, and (3) for any special or consequential damages to Certificateholders
(in addition to payment of principal and interest on the Certificates).

                                   ARTICLE XI

                            MISCELLANEOUS PROVISIONS

                  SECTION 11.01.            Amendment.

                  This Agreement may be amended from time to time by the
Depositor, the Master Servicer and the Trustee with the consent of the NIMS
Insurer and without the consent of any of the Certificateholders, (i) to cure
any ambiguity or defect, (ii) to correct, modify or supplement any provisions
herein (including to give effect to the expectations of Certificateholders), or
(iii) to make any other provisions with respect to matters or questions arising
under this Agreement which shall not be inconsistent with the provisions of this
Agreement, provided that such action shall not adversely affect in any material
respect the interests of any Certificateholder as evidenced by either (i) an
Opinion of Counsel delivered to the Master Servicer, the Trustee and the NIMS
Insurer or (ii) confirmation from the Rating Agencies, delivered to the Master
Servicer, the Trustee and the NIMS Insurer, that such amendment will not result
in the reduction or withdrawal of the rating of any outstanding Class of
Certificates. No amendment shall be deemed to adversely affect in any material
respect the interests of any Certificateholder who shall have consented thereto,
and no Opinion of Counsel shall be required to address the effect of any such
amendment on any such consenting Certificateholder.

                  This Agreement may also be amended from time to time by the
Depositor, the Master Servicer, the NIMS Insurer and the Trustee with the
consent of the NIMS Insurer and the Holders of Certificates entitled to at least
66% of the Voting Rights for the purpose of adding any provisions to or changing
in any manner or eliminating any of the provisions of this Agreement or of
modifying in any manner the rights of the Holders of Certificates; 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 interests of the
Holders of any Class of Certificates (as evidenced by either (i) an Opinion of
Counsel delivered to the Trustee and the NIMS Insurer or (ii) confirmation from
the Rating Agencies, delivered to the Master Servicer, the Trustee and the NIMS
Insurer, that such action will not result in the reduction or withdrawal of the
rating of any outstanding Class of Certificates) in a manner, other than as
described in (i), or (iii) modify the consents required by the immediately
preceding clauses (i) and (ii) without the consent of the Holders of all
Certificates then outstanding. Notwithstanding any other provision of this
Agreement, for purposes of the giving or withholding of consents pursuant to
this Section 11.01, Certificates registered in the name of the Depositor or the
Master Servicer or any Affiliate thereof shall be entitled to Voting Rights with
respect to matters affecting such Certificates.

                  Notwithstanding any contrary provision of this Agreement,
neither the Trustee nor the NIMS Insurer shall consent to any amendment to this
Agreement unless it shall have first received an Opinion of Counsel satisfactory
to the NIMS Insurer to the effect that such amendment will not result in the
imposition of any tax on any Trust REMIC pursuant to the REMIC Provisions

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<PAGE>

or cause any Trust REMIC to fail to qualify as a REMIC at any time that any
Certificates are outstanding.

                  Promptly after the execution of any such amendment the Trustee
shall furnish a copy of such amendment to each Certificateholder and the NIMS
Insurer.

                  It shall not be necessary for the consent of
Certificateholders under this Section 11.01 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.

                  The cost of any Opinion of Counsel to be delivered pursuant to
this Section 11.01 shall be borne by the Person seeking the related amendment,
but in no event shall such Opinion of Counsel be an expense of the Trustee.

                  The Trustee may, but shall not be obligated to enter into any
amendment pursuant to this Section that affects its rights, duties and
immunities under this Agreement or otherwise.

                  SECTION 11.02.            Recordation of Agreement;
                                            Counterparts.

                  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 at the expense of the Certificateholders, but
only upon direction of the Trustee 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 11.03.            Limitation on Rights of
                                            Certificateholders.

                  The death or incapacity of any Certificateholder shall not
operate to terminate this Agreement or the Trust, nor entitle such
Certificateholder's legal representatives or heirs to claim an accounting or to
take any action or proceeding in any court for a partition or winding up of the
Trust Fund, nor otherwise affect the rights, obligations and liabilities of the
parties hereto or any of them.

                  No Certificateholder shall have any right to vote (except as
expressly provided for herein) or in any manner otherwise control the operation
and management of the Trust, or the obligations of the parties hereto, nor shall
anything herein set forth, or contained in the terms of any of the Certificates,
be construed so as to constitute the Certificateholders from time to time as

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<PAGE>

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 shall have any right by virtue 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 also the
Holders of Certificates entitled to at least 25% of the Voting Rights 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 costs, expenses
and liabilities to be incurred therein or thereby, and the Trustee, for 15 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 is
understood and intended, and 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 whatsoever by virtue 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 equal,
ratable and common 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 11.04.            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 11.05.            Notices.

                  All directions, demands and notices hereunder shall be in
writing and shall be deemed to have been duly given when received if personally
delivered at or mailed by first class mail, postage prepaid, or by express
delivery service or delivered in any other manner specified herein, to (a) in
the case of the Depositor, 1285 Avenue of the Americas, New York, New York
10019, Attention: Glenn McIntyre (telecopy number (212) 713-2080), or such other
address or telecopy number as may hereafter be furnished to the Master Servicer,
the NIMS Insurer and the Trustee in writing by the Depositor, (b) in the case of
the Master Servicer, 3 Ada, Irvine California 92618, Attention: William O'Neill
(telecopy number: (949) 790-7401), or such other address or telecopy number as
may hereafter be furnished to the Trustee, the NIMS Insurer and the Depositor in
writing by the Master Servicer, (c) in the case of the Trustee, Wells Fargo Bank
Minnesota, National Association, P.O. Box 98, Columbia, Maryland 21046,
Attention: Client Manager--MASTR 2003- OPT1, with a copy to Wells Fargo Bank
Minnesota, National Association, 9062 Old Annapolis Road, Columbia, Maryland
21045-1951, Attention: MASTR Series 2003-OPT1, or such other address or telecopy
number as may hereafter be furnished to the Depositor, the NIMS Insurer and the
Master Servicer in writing by the Trustee, or such other address or telecopy
number as may

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<PAGE>

hereafter be furnished to the Master Servicer, the NIMS Insurer and the
Depositor in writing by the Trustee and (d) in the case of the NIMS Insurer, if
any, as applicable, (i) Radian Insurance Inc., 1601 Market Street, Philadelphia,
Pennsylvania 19103, Attention: General Counsel and (ii) Financial Security
Assurance Inc., 350 Park Avenue, New York, New York 10022, Attn: Transaction
Oversight, or such other address or telecopy number as may hereafter be
furnished to the Master Servicer, the Depositor and the Trustee in writing by
the NIMS Insurer. Any notice required or permitted to be given 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 so
mailed within the time prescribed in this Agreement shall be conclusively
presumed to have been duly given when mailed, whether or not the
Certificateholder receives such notice. A copy of any notice required to be
telecopied hereunder also shall be mailed to the appropriate party in the manner
set forth above.

                  SECTION 11.06.            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 11.07.            Notice to Rating Agencies and the
                                            NIMS Insurer.

                  The Trustee shall use its best efforts promptly to provide
notice to the Rating Agencies and the NIMS Insurer with respect to each of the
following of which it has actual knowledge:

                  1.       Any material change or amendment to this Agreement;

                  2.       The occurrence of any Master Servicer Event of
         Default that has not been cured or waived;

                  3.       The resignation or termination of the Master Servicer
         or the Trustee;

                  4.       The repurchase or substitution of Mortgage Loans
         pursuant to or as contemplated by Section 2.03;

                  5.       The final payment to the Holders of any Class of
         Certificates;

                  6.       Any change in the location of the Collection Account
         or the Distribution Account;

                  7.       Any event that would result in the inability of the
         Trustee to make advances regarding delinquent Mortgage Loans; and

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<PAGE>

                  8.       The filing of any claim under any Master Servicer's
         blanket bond and errors and omissions insurance policy required by
         Section 3.14 or the cancellation or material modification of coverage
         under any such instrument.

                  In addition, the Trustee shall promptly furnish to each Rating
Agency and the NIMS Insurer copies of each report to Certificateholders
described in Section 4.02 and the Master Servicer shall promptly furnish to each
Rating Agency copies of the following:

                  1.       Each annual statement as to compliance described in
         Section 3.20; and

                  2.       Each annual independent public accountants' servicing
         report described in Section 3.21.

                  Any such notice pursuant to this Section 11.07 shall be in
writing and shall be deemed to have been duly given if personally delivered at
or mailed by first class mail, postage prepaid, or by express delivery service
to Fitch Ratings, One State Street, 32nd Floor, New York, New York 10004,
Moody's Investors Service Inc., 99 Church Street, New York, New York 10004 and
Standard & Poor's Ratings Services, a division of the McGraw-Hill Companies,
Inc., 55 Water Street, New York, New York 10007 or such other addresses as the
Rating Agencies may designate in writing to the parties hereto.

                  SECTION 11.08.            Article and Section References.

                  All article and section references used in this Agreement,
unless otherwise provided, are to articles and sections in this Agreement.

                  SECTION 11.09.            Grant of Security Interest.

                  It is the express intent of the parties hereto that the
conveyance of the Mortgage Loans by the Depositor to the Trustee, be, and be
construed as, a sale of the Mortgage Loans by the Depositor and not a pledge of
the Mortgage Loans to secure a debt or other obligation of the Depositor.
However, in the event that, notwithstanding the aforementioned intent of the
parties, the Mortgage Loans are held to be property of the Depositor, then, (a)
it is the express intent of the parties that such conveyance be deemed a pledge
of the Mortgage Loans by the Depositor to the Trustee to secure a debt or other
obligation of the Depositor and (b)(1) this Agreement shall also be deemed to be
a security agreement within the meaning of Articles 8 and 9 of the Uniform
Commercial Code as in effect from time to time in the State of New York; (2) the
conveyance provided for in Section 2.01 hereof shall be deemed to be a grant by
the Depositor to the Trustee of a security interest in all of the Depositor's
right, title and interest in and to the Mortgage Loans and all amounts payable
to the holders of the Mortgage Loans in accordance with the terms thereof and
all proceeds of the conversion, voluntary or involuntary, of the foregoing into
cash, instruments, securities or other property, including without limitation
all amounts, other than investment earnings, from time to time held or invested
in the Collection Account and the Distribution Account, whether in the form of
cash, instruments, securities or other property; (3) the obligations secured by
such security agreement shall be deemed to be all of the Depositor's obligations
under this Agreement, including the obligation to provide to the
Certificateholders the benefits of this Agreement relating

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to the Mortgage Loans and the Trust Fund; and (4) notifications to persons
holding such property, and acknowledgments, receipts or confirmations from
persons holding such property, shall be deemed notifications to, or
acknowledgments, receipts or confirmations from, financial intermediaries,
bailees or agents (as applicable) of the Trustee for the purpose of perfecting
such security interest under applicable law. Accordingly, the Depositor hereby
grants to the Trustee a security interest in the Mortgage Loans and all other
property described in clause (2) of the preceding sentence, for the purpose of
securing to the Trustee the performance by the Depositor of the obligations
described in clause (3) of the preceding sentence. Notwithstanding the
foregoing, the parties hereto intend the conveyance pursuant to Section 2.01 to
be a true, absolute and unconditional sale of the Mortgage Loans and assets
constituting the Trust Fund by the Depositor to the Trustee.

                  SECTION 11.10             Third Party Rights.

                  The NIMs Insurer shall be deemed a third-party beneficiary of
this Agreement to the same extent as if it were a party hereto, and shall have
the right to enforce the provisions of this Agreement.

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<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, in each case as of the day and year first above
written.

                                         MORTGAGE ASSET SECURITIZATION
                                         TRANSACTIONS, INC.,
                                         as Depositor

                                         By:
                                            ------------------------------------
                                         Name:
                                         Title:

                                         By:
                                            ------------------------------------
                                         Name:
                                         Title:

                                         OPTION ONE MORTGAGE CORPORATION
                                         as Master Servicer

                                         By:
                                            ------------------------------------
                                         Name:
                                         Title:

                                         WELLS FARGO BANK MINNESOTA, NATIONAL
                                         ASSOCIATION, as Trustee

                                         By:
                                            ------------------------------------
                                         Name:
                                         Title:

                                      -145-

<PAGE>

STATE OF NEW YORK       )
                        ) ss.:
COUNTY OF NEW YORK      )

                  On the th day of February 2003, before me, a notary public in
and for said State, personally appeared ________________, known to me to be a
________________ of Mortgage Asset Securitization Transactions, Inc., one of the
corporations that executed the within instrument, and also known to me to be the
person who executed it on behalf of said corporation, and acknowledged to me
that such corporation executed the within instrument.

                  IN WITNESS WHEREOF, I have hereunto set my hand and affixed my
official seal the day and year in this certificate first above written.

                                                    ___________________________
                                                            Notary Public

[Notarial Seal]

                                      -146-

<PAGE>

STATE OF ______________         )
                                ) ss.:
COUNTY OF ____________          )

                  On the ____ day of February 2003, before me, a notary public
in and for said State, personally appeared _____________________, known to me to
be __________________ of Option One Mortgage Corporation, one of the
corporations that executed the within instrument, and also known to me to be the
person who executed it on behalf of said corporation, and acknowledged to me
that such corporation executed the within instrument.

                  IN WITNESS WHEREOF, I have hereunto set my hand and affixed my
official seal the day and year in this certificate first above written.

                                                    ___________________________
                                                            Notary Public

[Notarial Seal]

                                      -147-

<PAGE>

STATE OF MINNESOTA                  )
                                    )ss.:
COUNTY OF RAMSEY                    )

                  On the ____ day of February 2003, before me, a notary public
in and for said State, personally appeared ______________, known to me to be a
____________ of Wells Fargo Bank Minnesota, National Association, one of the
corporations that executed the within instrument, and also known to me to be the
person who executed it on behalf of said corporation, and acknowledged to me
that such corporation executed the within instrument.

                  IN WITNESS WHEREOF, I have hereunto set my hand and affixed my
official seal the day and year in this certificate first above written.

                                                    ___________________________
                                                            Notary Public

[Notarial Seal]

                                      -148-

<PAGE>

                                   EXHIBIT A-1

                          FORM OF CLASS A-1 CERTIFICATE

         UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF
         THE DEPOSITORY TRUST COMPANY, A NEW YORK CORPORATION ("DTC"), TO THE
         TRUSTEE OR ITS AGENT FOR REGISTRATION OF TRANSFER, EXCHANGE, OR
         PAYMENT, AND ANY CERTIFICATE ISSUED IS REGISTERED IN THE NAME OF CEDE &
         CO. OR IN SUCH OTHER NAME AS IS REQUESTED BY AN AUTHORIZED
         REPRESENTATIVE OF DTC (AND ANY PAYMENT IS MADE TO CEDE & CO. OR TO SUCH
         OTHER ENTITY AS IS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC),
         ANY TRANSFER, PLEDGE, OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR
         TO ANY PERSON IS WRONGFUL INASMUCH AS THE REGISTERED OWNER HEREOF, CEDE
         & CO., HAS AN INTEREST HEREIN.

         SOLELY FOR U.S. FEDERAL INCOME TAX PURPOSES, THIS CERTIFICATE IS A
         "REGULAR INTEREST" IN A "REAL ESTATE MORTGAGE INVESTMENT CONDUIT," AS
         THOSE TERMS ARE DEFINED, RESPECTIVELY, IN SECTIONS 860G AND 860D OF THE
         INTERNAL REVENUE CODE OF 1986 (THE "CODE").

<TABLE>
<CAPTION>
<S>                                                        <C>
Series: 2003-OPT1                                          Aggregate Certificate Principal Balance of the
                                                           Class A-1 Certificates as of the Issue Date:
Pass-Through Rate: Variable                                $[__]

Cut-off Date and date of Pooling and                       Denomination: $[__]
Servicing Agreement: February 1, 2003
                                                           Master Servicer:  Option One Mortgage
First Distribution Date: March 25, 2003                    Corporation

No. 1                                                      Trustee: Wells Fargo Bank Minnesota,
                                                           National Association

                                                           Issue Date: February [__], 2003

                                                           CUSIP: [___]
</TABLE>

         DISTRIBUTIONS IN REDUCTION OF THE CERTIFICATE PRINCIPAL
         BALANCE OF THIS CERTIFICATE MAY BE MADE MONTHLY AS SET
         FORTH HEREIN. ACCORDINGLY, THE OUTSTANDING CERTIFICATE
         PRINCIPAL BALANCE HEREOF AT ANY TIME MAY BE LESS THAN THE

                                      A-1-1

<PAGE>

         AMOUNT SHOWN ABOVE AS THE DENOMINATION OF THIS
         CERTIFICATE.

                        MORTGAGE PASS-THROUGH CERTIFICATE

evidencing a beneficial ownership interest in a portion of a Trust Fund (the
"Trust Fund") consisting primarily of a pool of conventional one- to
four-family, fixed-rate and adjustable-rate, first and second lien mortgage
loans (the "Mortgage Loans") formed and sold by

                MORTGAGE ASSET SECURITIZATION TRANSACTIONS, INC.

         THIS CERTIFICATE DOES NOT REPRESENT AN OBLIGATION OF OR INTEREST IN
         MORTGAGE ASSET SECURITIZATION TRANSACTIONS, INC., THE MASTER SERVICER,
         THE TRUSTEE OR ANY OF THEIR RESPECTIVE AFFILIATES. NEITHER THIS
         CERTIFICATE NOR THE UNDERLYING MORTGAGE LOANS ARE GUARANTEED BY ANY
         AGENCY OR INSTRUMENTALITY OF THE UNITED STATES.

                  This certifies that Cede & Co. is the registered owner of a
Percentage Interest (obtained by dividing the denomination of this Certificate
by the aggregate Certificate Principal Balance of the Class A-1 Certificates as
of the Issue Date) in that certain beneficial ownership interest evidenced by
all the Class A-1 Certificates in REMIC II created pursuant to a Pooling and
Servicing Agreement, dated as specified above (the "Agreement"), among Mortgage
Asset Securitization Transactions, Inc. (hereinafter called the "Depositor,"
which term includes any successor entity under the Agreement), the Master
Servicer and the Trustee, a summary of certain of the pertinent provisions of
which is set forth hereafter. To the extent not defined herein, the capitalized
terms used herein have the meanings assigned 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, distributions 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 (a "Distribution Date"), commencing on
the First Distribution Date specified above, to the Person in whose name this
Certificate is registered on the Record Date, in an amount equal to the product
of the Percentage Interest evidenced by this Certificate and the amount required
to be distributed to the Holders of Class A-1 Certificates on such Distribution
Date pursuant to the Agreement.

                  All distributions to the Holder of this Certificate under the
Agreement will be made or caused to be made by the Trustee by wire transfer in
immediately available funds to the account of the Person entitled thereto if
such Person shall have so notified the Trustee in writing at least five Business
Days prior to the Record Date immediately prior to such Distribution Date and is
the registered owner of Class A-1 Certificates the aggregate initial Certificate
Principal Balance of which is in excess of the lesser of (i) $5,000,000 or (ii)
two-thirds of the aggregate initial Certificate Principal Balance of the Class A
Certificates, or otherwise by check mailed by first class mail to the address of
the Person entitled thereto, as such name and address shall appear on the
Certificate

                                      A-1-2

<PAGE>

Register. Notwithstanding the above, the final distribution on this Certificate
will be made after due notice by the Trustee of the pendency of such
distribution and only upon presentation and surrender of this Certificate at the
office or agency appointed by the Trustee for that purpose as provided in the
Agreement.

                  The Pass-Through Rate applicable to the calculation of
interest payable with respect to this Certificate on any Distribution Date shall
equal a rate per annum equal to the lesser of (i) the related Formula Rate for
such Distribution Date and (ii) the related Net WAC Pass-Through Rate for such
Distribution Date.

                  This Certificate is one of a duly authorized issue of
Certificates designated as Mortgage Pass-Through Certificates of the Series
specified on the face hereof (herein called the "Certificates") and representing
a Percentage Interest in the Class of Certificates specified on the face hereof
equal to the denomination specified on the face hereof divided by the aggregate
Certificate Principal Balance of the Class of Certificates specified on the face
hereof.

                  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. As provided in the
Agreement, withdrawals from the Collection Account and the Distribution Account
may be made from time to time for purposes other than distributions to
Certificateholders, such purposes including reimbursement of advances made, or
certain expenses incurred, with respect to the Mortgage Loans.

                  The Agreement permits, with certain exceptions therein
provided, the amendment thereof and the modification of the rights and
obligations of the Depositor, the Master Servicer, 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
entitled to at least 66% of the Voting Rights. 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 herefor or in lieu hereof whether or not notation
of such consent is made upon this Certificate. The Agreement also permits the
amendment thereof, in certain limited 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 offices or agencies appointed by the Trustee as provided in
the Agreement, duly endorsed by, or accompanied by an assignment in the form
below or other written instrument of transfer in form satisfactory to the
Trustee duly executed by, the Holder hereof or such Holder's attorney duly
authorized in writing, and thereupon one or more new Certificates of the same
Class in authorized denominations evidencing the same aggregate Percentage
Interest will be issued to the designated transferee or transferees.

                  The Certificates are issuable in fully registered form only
without coupons in Classes and denominations representing Percentage Interests
specified in the Agreement. As provided in the Agreement and subject to certain
limitations therein set forth, the Certificates are exchangeable for new
Certificates of the same Class in authorized denominations evidencing the same
aggregate

                                      A-1-3

<PAGE>

Percentage Interest, as requested by the Holder surrendering the same. No
service charge will be made for any such registration of transfer or exchange of
Certificates, but the Trustee may require payment of a sum sufficient to cover
any tax or other governmental charge that may be imposed in connection with any
transfer or exchange of Certificates.

                  The Depositor, the Master Servicer, the Trustee and any agent
of the Depositor, the Master Servicer or the Trustee may treat the Person in
whose name this Certificate is registered as the owner hereof for all purposes,
and none of the Depositor, the Master Servicer, the Trustee nor any such agent
shall be affected by notice to the contrary.

                  The obligations created by the Agreement and the Trust Fund
created thereby shall terminate upon payment to the Certificateholders of all
amounts held by the Trustee and required to be paid to them pursuant to the
Agreement following the earlier of (i) the final payment or other liquidation
(or any advance with respect thereto) of the last Mortgage Loan and REO Property
remaining in REMIC I and (ii) the purchase by the party designated in the
Agreement at a price determined as provided in the Agreement from REMIC I of all
the Mortgage Loans and all property acquired in respect of such Mortgage Loans.
The Agreement permits, but does not require, the party designated in the
Agreement to purchase from REMIC I all the 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 right will effect early retirement of the
Certificates; however, such right to purchase is subject to the aggregate Stated
Principal Balance of the Mortgage Loans at the time of purchase being less than
10% of the aggregate principal balance of the Mortgage Loans as of the Cut-off
Date.

                  The recitals contained herein shall be taken as statements of
the Depositor and the Trustee assume no responsibility for their correctness.

                  Unless the certificate of authentication hereon has been
executed by the Trustee, by manual signature, this Certificate shall not be
entitled to any benefit under the Agreement or be valid for any purpose.

                                      A-1-4

<PAGE>

                  IN WITNESS WHEREOF, the Trustee has caused this Certificate to
be duly executed.

Dated: February __, 2003
                                            MASTR ASSET BACKED SECURITIES
                                             TRUST 2003-OPT1

                                            WELLS FARGO BANK MINNESOTA,
                                             NATIONAL ASSOCIATION, not in its
                                             individual capacity, but solely as
                                             Trustee

                                            By:______________________________
                                                    Authorized Officer

                          CERTIFICATE OF AUTHENTICATION
                          -----------------------------

         This is one of the Certificates referred to in the within-mentioned
Agreement.

                                            WELLS FARGO BANK MINNESOTA,
                                            NATIONAL ASSOCIATION, as Trustee

                                            By:______________________________
                                                    Authorized Signatory

                                      A-1-5

<PAGE>

                                  ABBREVIATIONS
                                  -------------

The following abbreviations, when used in the inscription on the face of this
instrument, shall be construed as though they were written out in full according
to applicable laws or regulations:

TEN COM - as tenants in common                     UNIF GIFT MIN ACT - Custodian

TEN ENT - as tenants by the entireties             (Cust) (Minor) under
                                                            Uniform Gifts
JT TEN - as joint tenants with right                        to Minors Act
         if survivorship and not as                 _______________
          tenants in common                            (State)

         Additional abbreviations may also be used though not in the above list.

                                   ASSIGNMENT
                                   ----------

                  FOR VALUE RECEIVED, the undersigned hereby sell(s), assign(s)
and transfer(s) unto ___________________________________________________________
________________________________________________________________________________
________________________________________________________________________________
(Please print or typewrite name, address including postal zip code, and Taxpayer
Identification Number of assignee) a Percentage Interest equal to ____%
evidenced by the within Mortgage Pass- Through Certificates and hereby
authorize(s) the registration of transfer of such interest to assignee on the
Certificate Register of the Trust Fund.

         I (we) further direct the Trustee to issue a new Certificate of a like
Percentage Interest and Class to the above named assignee and deliver such
Certificate to the following address:
______________________________________________________________________________
______________________________________________________________________________.

Dated:

                                           _____________________________________
                                           Signature by or on behalf of assignor

                                           _____________________________________
                                           Signature Guaranteed

                                      A-1-6

<PAGE>

                            DISTRIBUTION INSTRUCTIONS

         The assignee should include the following for purposes of distribution:

         Distributions shall be made, 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.

                                      A-1-7

<PAGE>

                                   EXHIBIT A-2
                                   -----------

                          FORM OF CLASS A-2 CERTIFICATE

         UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF
         THE DEPOSITORY TRUST COMPANY, A NEW YORK CORPORATION ("DTC"), TO THE
         TRUSTEE OR ITS AGENT FOR REGISTRATION OF TRANSFER, EXCHANGE, OR
         PAYMENT, AND ANY CERTIFICATE ISSUED IS REGISTERED IN THE NAME OF CEDE &
         CO. OR IN SUCH OTHER NAME AS IS REQUESTED BY AN AUTHORIZED
         REPRESENTATIVE OF DTC (AND ANY PAYMENT IS MADE TO CEDE & CO. OR TO SUCH
         OTHER ENTITY AS IS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC),
         ANY TRANSFER, PLEDGE, OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR
         TO ANY PERSON IS WRONGFUL INASMUCH AS THE REGISTERED OWNER HEREOF, CEDE
         & CO., HAS AN INTEREST HEREIN.

         SOLELY FOR U.S. FEDERAL INCOME TAX PURPOSES, THIS CERTIFICATE IS A
         "REGULAR INTEREST" IN A "REAL ESTATE MORTGAGE INVESTMENT CONDUIT," AS
         THOSE TERMS ARE DEFINED, RESPECTIVELY, IN SECTIONS 860G AND 860D OF THE
         INTERNAL REVENUE CODE OF 1986 (THE "CODE").

<TABLE>
<CAPTION>
<S>                                                        <C>
Series:  2003-OPT1                                         Aggregate Certificate Principal Balance of the
                                                           Class A-2 Certificates as of the Issue Date:
Pass-Through Rate: Variable                                $[___]

Cut-off Date and date of Pooling and                       Denomination: $[___]
Servicing Agreement: February 1, 2003
                                                           Master Servicer:  Option One Mortgage
First Distribution Date: March 25, 2003                    Corporation

No. 1                                                      Trustee: Wells Fargo Bank Minnesota,
                                                           National Association

                                                           Issue Date: February [__], 2003

                                                           CUSIP: [___]
</TABLE>

         DISTRIBUTIONS IN REDUCTION OF THE CERTIFICATE PRINCIPAL BALANCE OF THIS
         CERTIFICATE MAY BE MADE MONTHLY AS SET FORTH HEREIN. ACCORDINGLY, THE
         OUTSTANDING CERTIFICATE PRINCIPAL BALANCE HEREOF AT ANY TIME MAY BE
         LESS THAN THE AMOUNT SHOWN ABOVE AS THE DENOMINATION OF THIS
         CERTIFICATE.

                                      A-1-8

<PAGE>

                        MORTGAGE PASS-THROUGH CERTIFICATE

evidencing a beneficial ownership interest in a portion of a Trust Fund (the
"Trust Fund") consisting primarily of a pool of conventional one- to
four-family, fixed-rate and adjustable-rate, first and second lien mortgage
loans (the "Mortgage Loans") formed and sold by

                MORTGAGE ASSET SECURITIZATION TRANSACTIONS, INC.

         THIS CERTIFICATE DOES NOT REPRESENT AN OBLIGATION OF OR INTEREST IN
         MORTGAGE ASSET SECURITIZATION TRANSACTIONS, INC., THE MASTER SERVICER,
         THE TRUSTEE OR ANY OF THEIR RESPECTIVE AFFILIATES. NEITHER THIS
         CERTIFICATE NOR THE UNDERLYING MORTGAGE LOANS ARE GUARANTEED BY ANY
         AGENCY OR INSTRUMENTALITY OF THE UNITED STATES.

                  This certifies that Cede & Co. is the registered owner of a
Percentage Interest (obtained by dividing the denomination of this Certificate
by the aggregate Certificate Principal Balance of the Class A-2 Certificates as
of the Issue Date) in that certain beneficial ownership interest evidenced by
all the Class A-2 Certificates in REMIC II created pursuant to a Pooling and
Servicing Agreement, dated as specified above (the "Agreement"), among Mortgage
Asset Securitization Transactions, Inc. (hereinafter called the "Depositor,"
which term includes any successor entity under the Agreement), the Master
Servicer and the Trustee, a summary of certain of the pertinent provisions of
which is set forth hereafter. To the extent not defined herein, the capitalized
terms used herein have the meanings assigned 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, distributions 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 (a "Distribution Date"), commencing on
the First Distribution Date specified above, to the Person in whose name this
Certificate is registered on the Record Date, in an amount equal to the product
of the Percentage Interest evidenced by this Certificate and the amount required
to be distributed to the Holders of Class A-2 Certificates on such Distribution
Date pursuant to the Agreement.

                  All distributions to the Holder of this Certificate under the
Agreement will be made or caused to be made by the Trustee by wire transfer in
immediately available funds to the account of the Person entitled thereto if
such Person shall have so notified the Trustee in writing at least five Business
Days prior to the Record Date immediately prior to such Distribution Date and is
the registered owner of Class A-2 Certificates the aggregate initial Certificate
Principal Balance of which is in excess of the lesser of (i) $5,000,000 or (ii)
two-thirds of the aggregate initial Certificate Principal Balance of the Class A
Certificates, or otherwise by check mailed by first class mail 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 by the Trustee of the pendency of such
distribution and only upon presentation and surrender

                                      A-1-9

<PAGE>

of this Certificate at the office or agency appointed by the Trustee for that
purpose as provided in the Agreement.

                  The Pass-Through Rate applicable to the calculation of
interest payable with respect to this Certificate on any Distribution Date shall
equal a rate per annum equal to the lesser of (i) the related Formula Rate for
such Distribution Date and (ii) the related Net WAC Pass-Through Rate for such
Distribution Date.

                  This Certificate is one of a duly authorized issue of
Certificates designated as Mortgage Pass-Through Certificates of the Series
specified on the face hereof (herein called the "Certificates") and representing
a Percentage Interest in the Class of Certificates specified on the face hereof
equal to the denomination specified on the face hereof divided by the aggregate
Certificate Principal Balance of the Class of Certificates specified on the face
hereof.

                  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. As provided in the
Agreement, withdrawals from the Collection Account and the Distribution Account
may be made from time to time for purposes other than distributions to
Certificateholders, such purposes including reimbursement of advances made, or
certain expenses incurred, with respect to the Mortgage Loans.

                  The Agreement permits, with certain exceptions therein
provided, the amendment thereof and the modification of the rights and
obligations of the Depositor, the Master Servicer, 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
entitled to at least 66% of the Voting Rights. 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 herefor or in lieu hereof whether or not notation
of such consent is made upon this Certificate. The Agreement also permits the
amendment thereof, in certain limited 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 offices or agencies appointed by the Trustee as provided in
the Agreement, duly endorsed by, or accompanied by an assignment in the form
below or other written instrument of transfer in form satisfactory to the
Trustee duly executed by, the Holder hereof or such Holder's attorney duly
authorized in writing, and thereupon one or more new Certificates of the same
Class in authorized denominations evidencing the same aggregate Percentage
Interest will be issued to the designated transferee or transferees.

                  The Certificates are issuable in fully registered form only
without coupons in Classes and denominations representing Percentage Interests
specified in the Agreement. As provided in the Agreement and subject to certain
limitations therein set forth, the Certificates are exchangeable for new
Certificates of the same Class in authorized denominations evidencing the same
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
of Certificates, but the Trustee may require

                                     A-1-10

<PAGE>

payment of a sum sufficient to cover any tax or other governmental charge that
may be imposed in connection with any transfer or exchange of Certificates.

                  The Depositor, the Master Servicer, the Trustee and any agent
of the Depositor, the Master Servicer or the Trustee may treat the Person in
whose name this Certificate is registered as the owner hereof for all purposes,
and none of the Depositor, the Master Servicer, the Trustee nor any such agent
shall be affected by notice to the contrary.

                  The obligations created by the Agreement and the Trust Fund
created thereby shall terminate upon payment to the Certificateholders of all
amounts held by the Trustee and required to be paid to them pursuant to the
Agreement following the earlier of (i) the final payment or other liquidation
(or any advance with respect thereto) of the last Mortgage Loan and REO Property
remaining in REMIC I and (ii) the purchase by the party designated in the
Agreement at a price determined as provided in the Agreement from REMIC I of all
the Mortgage Loans and all property acquired in respect of such Mortgage Loans.
The Agreement permits, but does not require, the party designated in the
Agreement to purchase from REMIC I all the 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 right will effect early retirement of the
Certificates; however, such right to purchase is subject to the aggregate Stated
Principal Balance of the Mortgage Loans at the time of purchase being less than
10% of the aggregate principal balance of the Mortgage Loans as of the Cut-off
Date.

                  The recitals contained herein shall be taken as statements of
the Depositor and the Trustee assume no responsibility for their correctness.

                  Unless the certificate of authentication hereon has been
executed by the Trustee, by manual signature, this Certificate shall not be
entitled to any benefit under the Agreement or be valid for any purpose.

                                     A-1-11

<PAGE>

                  IN WITNESS WHEREOF, the Trustee has caused this Certificate to
be duly executed.

Dated: February __, 2003
                                            MASTR ASSET BACKED SECURITIES
                                             TRUST 2003-OPT1

                                            WELLS FARGO BANK MINNESOTA,
                                             NATIONAL ASSOCIATION, not in its
                                             individual capacity, but solely as
                                             Trustee

                                            By:______________________________
                                                    Authorized Officer

                          CERTIFICATE OF AUTHENTICATION
                          -----------------------------

         This is one of the Certificates referred to in the within-mentioned
Agreement.

                                            WELLS FARGO BANK MINNESOTA,
                                            NATIONAL ASSOCIATION, as Trustee

                                            By:______________________________
                                                    Authorized Signatory

                                      A-1-12

<PAGE>

                                  ABBREVIATIONS
                                  -------------

The following abbreviations, when used in the inscription on the face of this
instrument, shall be construed as though they were written out in full according
to applicable laws or regulations:

TEN COM - as tenants in common                     UNIF GIFT MIN ACT - Custodian

TEN ENT - as tenants by the entireties             (Cust) (Minor) under
                                                            Uniform Gifts
JT TEN - as joint tenants with right                        to Minors Act
         if survivorship and not as                 _______________
          tenants in common                            (State)

         Additional abbreviations may also be used though not in the above list.

                                   ASSIGNMENT
                                   ----------

                  FOR VALUE RECEIVED, the undersigned hereby sell(s), assign(s)
and transfer(s) unto ___________________________________________________________
________________________________________________________________________________
________________________________________________________________________________
(Please print or typewrite name, address including postal zip code, and Taxpayer
Identification Number of assignee) a Percentage Interest equal to ____%
evidenced by the within Mortgage Pass- Through Certificates and hereby
authorize(s) the registration of transfer of such interest to assignee on the
Certificate Register of the Trust Fund.

         I (we) further direct the Trustee to issue a new Certificate of a like
Percentage Interest and Class to the above named assignee and deliver such
Certificate to the following address:
______________________________________________________________________________
______________________________________________________________________________.

Dated:

                                           _____________________________________
                                           Signature by or on behalf of assignor

                                           _____________________________________
                                           Signature Guaranteed

                                      A-1-13

<PAGE>

                            DISTRIBUTION INSTRUCTIONS

         The assignee should include the following for purposes of distribution:

         Distributions shall be made, 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.

                                     A-1-14

<PAGE>

                                   EXHIBIT A-3
                                   -----------

                          FORM OF CLASS M-1 CERTIFICATE

         UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF
         THE DEPOSITORY TRUST COMPANY, A NEW YORK CORPORATION ("DTC"), TO THE
         TRUSTEE OR ITS AGENT FOR REGISTRATION OF TRANSFER, EXCHANGE, OR
         PAYMENT, AND ANY CERTIFICATE ISSUED IS REGISTERED IN THE NAME OF CEDE &
         CO. OR IN SUCH OTHER NAME AS IS REQUESTED BY AN AUTHORIZED
         REPRESENTATIVE OF DTC (AND ANY PAYMENT IS MADE TO CEDE & CO. OR TO SUCH
         OTHER ENTITY AS IS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC),
         ANY TRANSFER, PLEDGE, OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR
         TO ANY PERSON IS WRONGFUL INASMUCH AS THE REGISTERED OWNER HEREOF, CEDE
         & CO., HAS AN INTEREST HEREIN.

         SOLELY FOR U.S. FEDERAL INCOME TAX PURPOSES, THIS CERTIFICATE IS A
         "REGULAR INTEREST" IN A "REAL ESTATE MORTGAGE INVESTMENT CONDUIT," AS
         THOSE TERMS ARE DEFINED, RESPECTIVELY, IN SECTIONS 860G AND 860D OF THE
         INTERNAL REVENUE CODE OF 1986 (THE "CODE").

         THIS CERTIFICATE IS SUBORDINATE TO THE CLASS A-1 CERTIFICATES AND THE
         CLASS A-2 CERTIFICATES TO THE EXTENT DESCRIBED IN THE POOLING AND
         SERVICING AGREEMENT REFERRED TO HEREIN.

         NO TRANSFER OF THIS CERTIFICATE TO AN EMPLOYEE BENEFIT PLAN OR OTHER
         RETIREMENT ARRANGEMENT SUBJECT TO THE EMPLOYEE RETIREMENT INCOME
         SECURITY ACT OF 1974, AS AMENDED, OR THE CODE WILL BE REGISTERED EXCEPT
         IN COMPLIANCE WITH THE PROCEDURES DESCRIBED HEREIN.

                                      A-2-1

<PAGE>

<TABLE>
<CAPTION>
<S>                                                        <C>
Series:  2003-OPT1                                         Aggregate Certificate Principal Balance of the
                                                           Class M-1 Certificates as of the Issue Date:
Pass-Through Rate: Variable                                $[____]

Cut-off Date and date of Pooling and                       Denomination: $[____]
Servicing Agreement: February 1, 2003
                                                           Master Servicer:  Option One Mortgage
First Distribution Date: March 25, 2003                    Corporation

No. 1                                                      Trustee: Wells Fargo Bank Minnesota,
                                                           National Association

                                                           Issue Date: February [__], 2003

                                                           CUSIP: [____]
</TABLE>

         DISTRIBUTIONS IN REDUCTION OF THE CERTIFICATE PRINCIPAL BALANCE OF THIS
         CERTIFICATE MAY BE MADE MONTHLY AS SET FORTH HEREIN. ACCORDINGLY, THE
         OUTSTANDING CERTIFICATE PRINCIPAL BALANCE HEREOF AT ANY TIME MAY BE
         LESS THAN THE AMOUNT SHOWN ABOVE AS THE DENOMINATION OF THIS
         CERTIFICATE.

                                      A-2-2

<PAGE>

                        MORTGAGE PASS-THROUGH CERTIFICATE

evidencing a beneficial ownership interest in a portion of a Trust Fund (the
"Trust Fund") consisting primarily of a pool of conventional one- to
four-family, fixed-rate and adjustable-rate, first and second lien mortgage
loans (the "Mortgage Loans") formed and sold by

                MORTGAGE ASSET SECURITIZATION TRANSACTIONS, INC.

         THIS CERTIFICATE DOES NOT REPRESENT AN OBLIGATION OF OR INTEREST IN
         MORTGAGE ASSET SECURITIZATION TRANSACTIONS, INC., THE MASTER SERVICER,
         THE TRUSTEE OR ANY OF THEIR RESPECTIVE AFFILIATES. NEITHER THIS
         CERTIFICATE NOR THE UNDERLYING MORTGAGE LOANS ARE GUARANTEED BY ANY
         AGENCY OR INSTRUMENTALITY OF THE UNITED STATES.

                  This certifies that Cede & Co. is the registered owner of a
Percentage Interest (obtained by dividing the denomination of this Certificate
by the aggregate Certificate Principal Balance of the Class M-1 Certificates as
of the Issue Date) in that certain beneficial ownership interest evidenced by
all the Class M-1 Certificates in REMIC II created pursuant to a Pooling and
Servicing Agreement, dated as specified above (the "Agreement"), among Mortgage
Asset Securitization Transactions, Inc. (hereinafter called the "Depositor,"
which term includes any successor entity under the Agreement), the Master
Servicer and the Trustee, a summary of certain of the pertinent provisions of
which is set forth hereafter. To the extent not defined herein, the capitalized
terms used herein have the meanings assigned 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, distributions 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 (a "Distribution Date"), commencing on
the First Distribution Date specified above, to the Person in whose name this
Certificate is registered on the Record Date, in an amount equal to the product
of the Percentage Interest evidenced by this Certificate and the amount required
to be distributed to the Holders of Class M-1 Certificates on such Distribution
Date pursuant to the Agreement.

                  All distributions to the Holder of this Certificate under the
Agreement will be made or caused to be made by the Trustee by wire transfer in
immediately available funds to the account of the Person entitled thereto if
such Person shall have so notified the Trustee in writing at least five Business
Days prior to the Record Date immediately prior to such Distribution Date and is
the registered owner of Class M-1 Certificates the aggregate initial Certificate
Principal Balance of which is in excess of the lesser of (i) $5,000,000 or (ii)
two-thirds of the aggregate initial Certificate Principal Balance of the Class
M-1 Certificates, or otherwise by check mailed by first class mail 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 by the Trustee of the pendency of
such distribution and only upon presentation and surrender

                                      A-2-3

<PAGE>

of this Certificate at the office or agency appointed by the Trustee for that
purpose as provided in the Agreement.

                  The Pass-Through Rate applicable to the calculation of
interest payable with respect to this Certificate on any Distribution Date shall
equal a rate per annum equal to the lesser of (i) the related Formula Rate for
such Distribution Date and (ii) the related Net WAC Pass-Through Rate for such
Distribution Date.

                  This Certificate is one of a duly authorized issue of
Certificates designated as Mortgage Pass-Through Certificates of the Series
specified on the face hereof (herein called the "Certificates") and representing
a Percentage Interest in the Class of Certificates specified on the face hereof
equal to the denomination specified on the face hereof divided by the aggregate
Certificate Principal Balance of the Class of Certificates specified on the face
hereof.

                  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. As provided in the
Agreement, withdrawals from the Collection Account and the Distribution Account
may be made from time to time for purposes other than distributions to
Certificateholders, such purposes including reimbursement of advances made, or
certain expenses incurred, with respect to the Mortgage Loans.

                  The Agreement permits, with certain exceptions therein
provided, the amendment thereof and the modification of the rights and
obligations of the Depositor, the Master Servicer, 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
entitled to at least 66% of the Voting Rights. 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 herefor or in lieu hereof whether or not notation
of such consent is made upon this Certificate. The Agreement also permits the
amendment thereof, in certain limited 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 offices or agencies appointed by the Trustee as provided in
the Agreement, duly endorsed by, or accompanied by an assignment in the form
below or other written instrument of transfer in form satisfactory to the
Trustee duly executed by, the Holder hereof or such Holder's attorney duly
authorized in writing, and thereupon one or more new Certificates of the same
Class in authorized denominations evidencing the same aggregate Percentage
Interest will be issued to the designated transferee or transferees.

                  No transfer of this Certificate to a Plan subject to ERISA or
Section 4975 of the Code, any Person acting, directly or indirectly, on behalf
of any such Plan or any Person using "Plan Assets" to acquire this Certificate
shall be made except in accordance with Section 5.02(c) of the Agreement.

                                      A-2-4

<PAGE>

                  The Certificates are issuable in fully registered form only
without coupons in Classes and denominations representing Percentage Interests
specified in the Agreement. As provided in the Agreement and subject to certain
limitations therein set forth, the Certificates are exchangeable for new
Certificates of the same Class in authorized denominations evidencing the same
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
of Certificates, but the Trustee may require payment of a sum sufficient to
cover any tax or other governmental charge that may be imposed in connection
with any transfer or exchange of Certificates.

                  The Depositor, the Master Servicer, the Trustee and any agent
of the Depositor, the Master Servicer or the Trustee may treat the Person in
whose name this Certificate is registered as the owner hereof for all purposes,
and none of the Depositor, the Master Servicer, the Trustee nor any such agent
shall be affected by notice to the contrary.

                  The obligations created by the Agreement and the Trust Fund
created thereby shall terminate upon payment to the Certificateholders of all
amounts held by the Trustee and required to be paid to them pursuant to the
Agreement following the earlier of (i) the final payment or other liquidation
(or any advance with respect thereto) of the last Mortgage Loan and REO Property
remaining in REMIC I and (ii) the purchase by the party designated in the
Agreement at a price determined as provided in the Agreement from REMIC I of all
the Mortgage Loans and all property acquired in respect of such Mortgage Loans.
The Agreement permits, but does not require, the party designated in the
Agreement to purchase from REMIC I all the 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 right will effect early retirement of the
Certificates; however, such right to purchase is subject to the aggregate Stated
Principal Balance of the Mortgage Loans at the time of purchase being less than
10% of the aggregate principal balance of the Mortgage Loans as of the Cut-off
Date.

                  The recitals contained herein shall be taken as statements of
the Depositor and the Trustee assume no responsibility for their correctness.

                  Unless the certificate of authentication hereon has been
executed by the Trustee, by manual signature, this Certificate shall not be
entitled to any benefit under the Agreement or be valid for any purpose.

                                      A-2-5

<PAGE>

                  IN WITNESS WHEREOF, the Trustee has caused this Certificate to
be duly executed.

Dated: February __, 2003
                                            MASTR ASSET BACKED SECURITIES
                                             TRUST 2003-OPT1

                                            WELLS FARGO BANK MINNESOTA,
                                             NATIONAL ASSOCIATION, not in its
                                             individual capacity, but solely as
                                             Trustee

                                            By:______________________________
                                                    Authorized Officer

                          CERTIFICATE OF AUTHENTICATION
                          -----------------------------

         This is one of the Certificates referred to in the within-mentioned
Agreement.

                                            WELLS FARGO BANK MINNESOTA,
                                            NATIONAL ASSOCIATION, as Trustee

                                            By:______________________________
                                                    Authorized Signatory

                                      A-2-6

<PAGE>

                                  ABBREVIATIONS
                                  -------------

The following abbreviations, when used in the inscription on the face of this
instrument, shall be construed as though they were written out in full according
to applicable laws or regulations:

TEN COM - as tenants in common                     UNIF GIFT MIN ACT - Custodian

TEN ENT - as tenants by the entireties             (Cust) (Minor) under
                                                            Uniform Gifts
JT TEN - as joint tenants with right                        to Minors Act
         if survivorship and not as                 _______________
          tenants in common                            (State)

         Additional abbreviations may also be used though not in the above list.

                                   ASSIGNMENT
                                   ----------

                  FOR VALUE RECEIVED, the undersigned hereby sell(s), assign(s)
and transfer(s) unto ___________________________________________________________
________________________________________________________________________________
________________________________________________________________________________
(Please print or typewrite name, address including postal zip code, and Taxpayer
Identification Number of assignee) a Percentage Interest equal to ____%
evidenced by the within Mortgage Pass- Through Certificates and hereby
authorize(s) the registration of transfer of such interest to assignee on the
Certificate Register of the Trust Fund.

         I (we) further direct the Trustee to issue a new Certificate of a like
Percentage Interest and Class to the above named assignee and deliver such
Certificate to the following address:
______________________________________________________________________________
______________________________________________________________________________.

Dated:

                                           _____________________________________
                                           Signature by or on behalf of assignor

                                           _____________________________________
                                           Signature Guaranteed

                                      A-2-7

<PAGE>

                            DISTRIBUTION INSTRUCTIONS

         The assignee should include the following for purposes of distribution:

         Distributions shall be made, 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.

                                      A-2-8

<PAGE>

                                   EXHIBIT A-4
                                   -----------

                          FORM OF CLASS M-2 CERTIFICATE

         UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF
         THE DEPOSITORY TRUST COMPANY, A NEW YORK CORPORATION ("DTC"), TO THE
         TRUSTEE OR ITS AGENT FOR REGISTRATION OF TRANSFER, EXCHANGE, OR
         PAYMENT, AND ANY CERTIFICATE ISSUED IS REGISTERED IN THE NAME OF CEDE &
         CO. OR IN SUCH OTHER NAME AS IS REQUESTED BY AN AUTHORIZED
         REPRESENTATIVE OF DTC (AND ANY PAYMENT IS MADE TO CEDE & CO. OR TO SUCH
         OTHER ENTITY AS IS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC),
         ANY TRANSFER, PLEDGE, OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR
         TO ANY PERSON IS WRONGFUL INASMUCH AS THE REGISTERED OWNER HEREOF, CEDE
         & CO., HAS AN INTEREST HEREIN.

         SOLELY FOR U.S. FEDERAL INCOME TAX PURPOSES, THIS CERTIFICATE IS A
         "REGULAR INTEREST" IN A "REAL ESTATE MORTGAGE INVESTMENT CONDUIT," AS
         THOSE TERMS ARE DEFINED, RESPECTIVELY, IN SECTIONS 860G AND 860D OF THE
         INTERNAL REVENUE CODE OF 1986 (THE "CODE").

         THIS CERTIFICATE IS SUBORDINATE TO THE CLASS A-1 CERTIFICATES, THE
         CLASS A-2 CERTIFICATES AND THE CLASS M-1 CERTIFICATES TO THE EXTENT
         DESCRIBED IN THE POOLING AND SERVICING AGREEMENT REFERRED TO HEREIN.

         NO TRANSFER OF THIS CERTIFICATE TO AN EMPLOYEE BENEFIT PLAN OR OTHER
         RETIREMENT ARRANGEMENT SUBJECT TO THE EMPLOYEE RETIREMENT INCOME
         SECURITY ACT OF 1974, AS AMENDED, OR THE CODE WILL BE REGISTERED EXCEPT
         IN COMPLIANCE WITH THE PROCEDURES DESCRIBED HEREIN.

                                      A-3-1

<PAGE>

<TABLE>
<CAPTION>
<S>                                                        <C>
Series:  2003-OPT1                                         Aggregate Certificate Principal Balance of the
                                                           Class M-2 Certificates as of the Issue Date:
Pass-Through Rate: Variable                                $[____]

Cut-off Date and date of Pooling and                       Denomination: $[____]
Servicing Agreement: February 1, 2003
                                                           Master Servicer:  Option One Mortgage
First Distribution Date: March 25, 2003                    Corporation

No. 1                                                      Trustee: Wells Fargo Bank Minnesota,
                                                           National Association

                                                           Issue Date: February [__], 2003

                                                           CUSIP: [____]
</TABLE>

         DISTRIBUTIONS IN REDUCTION OF THE CERTIFICATE PRINCIPAL BALANCE OF THIS
         CERTIFICATE MAY BE MADE MONTHLY AS SET FORTH HEREIN. ACCORDINGLY, THE
         OUTSTANDING CERTIFICATE PRINCIPAL BALANCE HEREOF AT ANY TIME MAY BE
         LESS THAN THE AMOUNT SHOWN ABOVE AS THE DENOMINATION OF THIS
         CERTIFICATE.

                                      A-3-2

<PAGE>

                        MORTGAGE PASS-THROUGH CERTIFICATE

evidencing a beneficial ownership interest in a portion of a Trust Fund (the
"Trust Fund") consisting primarily of a pool of conventional one- to
four-family, fixed-rate and adjustable-rate, first and second lien mortgage
loans (the "Mortgage Loans") formed and sold by

                MORTGAGE ASSET SECURITIZATION TRANSACTIONS, INC.

         THIS CERTIFICATE DOES NOT REPRESENT AN OBLIGATION OF OR INTEREST IN
         MORTGAGE ASSET SECURITIZATION TRANSACTIONS, INC., THE MASTER SERVICER,
         THE TRUSTEE OR ANY OF THEIR RESPECTIVE AFFILIATES. NEITHER THIS
         CERTIFICATE NOR THE UNDERLYING MORTGAGE LOANS ARE GUARANTEED BY ANY
         AGENCY OR INSTRUMENTALITY OF THE UNITED STATES.

                  This certifies that Cede & Co. is the registered owner of a
Percentage Interest (obtained by dividing the denomination of this Certificate
by the aggregate Certificate Principal Balance of the Class M-2 Certificates as
of the Issue Date) in that certain beneficial ownership interest evidenced by
all the Class M-2 Certificates in REMIC II created pursuant to a Pooling and
Servicing Agreement, dated as specified above (the "Agreement"), among Mortgage
Asset Securitization Transactions, Inc. (hereinafter called the "Depositor,"
which term includes any successor entity under the Agreement), the Master
Servicer and the Trustee, a summary of certain of the pertinent provisions of
which is set forth hereafter. To the extent not defined herein, the capitalized
terms used herein have the meanings assigned 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, distributions 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 (a "Distribution Date"), commencing on
the First Distribution Date specified above, to the Person in whose name this
Certificate is registered on the Record Date, in an amount equal to the product
of the Percentage Interest evidenced by this Certificate and the amount required
to be distributed to the Holders of Class M-2 Certificates on such Distribution
Date pursuant to the Agreement.

                  All distributions to the Holder of this Certificate under the
Agreement will be made or caused to be made by the Trustee by wire transfer in
immediately available funds to the account of the Person entitled thereto if
such Person shall have so notified the Trustee in writing at least five Business
Days prior to the Record Date immediately prior to such Distribution Date and is
the registered owner of Class M-2 Certificates the aggregate initial Certificate
Principal Balance of which is in excess of the lesser of (i) $5,000,000 or (ii)
two-thirds of the aggregate initial Certificate Principal Balance of the Class
M-2 Certificates, or otherwise by check mailed by first class mail 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 by the Trustee of the pendency of
such distribution and only upon presentation and surrender

                                      A-3-3

<PAGE>

of this Certificate at the office or agency appointed by the Trustee for that
purpose as provided in the Agreement.

                  The Pass-Through Rate applicable to the calculation of
interest payable with respect to this Certificate on any Distribution Date shall
equal a rate per annum equal to the lesser of (i) the related Formula Rate for
such Distribution Date and (ii) the related Net WAC Pass-Through Rate for such
Distribution Date.

                  This Certificate is one of a duly authorized issue of
Certificates designated as Mortgage Pass-Through Certificates of the Series
specified on the face hereof (herein called the "Certificates") and representing
a Percentage Interest in the Class of Certificates specified on the face hereof
equal to the denomination specified on the face hereof divided by the aggregate
Certificate Principal Balance of the Class of Certificates specified on the face
hereof.

                  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. As provided in the
Agreement, withdrawals from the Collection Account and the Distribution Account
may be made from time to time for purposes other than distributions to
Certificateholders, such purposes including reimbursement of advances made, or
certain expenses incurred, with respect to the Mortgage Loans.

                  The Agreement permits, with certain exceptions therein
provided, the amendment thereof and the modification of the rights and
obligations of the Depositor, the Master Servicer, 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
entitled to at least 66% of the Voting Rights. 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 herefor or in lieu hereof whether or not notation
of such consent is made upon this Certificate. The Agreement also permits the
amendment thereof, in certain limited 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 offices or agencies appointed by the Trustee as provided in
the Agreement, duly endorsed by, or accompanied by an assignment in the form
below or other written instrument of transfer in form satisfactory to the
Trustee duly executed by, the Holder hereof or such Holder's attorney duly
authorized in writing, and thereupon one or more new Certificates of the same
Class in authorized denominations evidencing the same aggregate Percentage
Interest will be issued to the designated transferee or transferees.

                  No transfer of this Certificate to a Plan subject to ERISA or
Section 4975 of the Code, any Person acting, directly or indirectly, on behalf
of any such Plan or any Person using "Plan Assets" to acquire this Certificate
shall be made except in accordance with Section 5.02(c) of the Agreement.

                                      A-3-4

<PAGE>

                  The Certificates are issuable in fully registered form only
without coupons in Classes and denominations representing Percentage Interests
specified in the Agreement. As provided in the Agreement and subject to certain
limitations therein set forth, the Certificates are exchangeable for new
Certificates of the same Class in authorized denominations evidencing the same
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
of Certificates, but the Trustee may require payment of a sum sufficient to
cover any tax or other governmental charge that may be imposed in connection
with any transfer or exchange of Certificates.

                  The Depositor, the Master Servicer, the Trustee and any agent
of the Depositor, the Master Servicer or the Trustee may treat the Person in
whose name this Certificate is registered as the owner hereof for all purposes,
and none of the Depositor, the Master Servicer, the Trustee nor any such agent
shall be affected by notice to the contrary.

                  The obligations created by the Agreement and the Trust Fund
created thereby shall terminate upon payment to the Certificateholders of all
amounts held by the Trustee and required to be paid to them pursuant to the
Agreement following the earlier of (i) the final payment or other liquidation
(or any advance with respect thereto) of the last Mortgage Loan and REO Property
remaining in REMIC I and (ii) the purchase by the party designated in the
Agreement at a price determined as provided in the Agreement from REMIC I of all
the Mortgage Loans and all property acquired in respect of such Mortgage Loans.
The Agreement permits, but does not require, the party designated in the
Agreement to purchase from REMIC I all the 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 right will effect early retirement of the
Certificates; however, such right to purchase is subject to the aggregate Stated
Principal Balance of the Mortgage Loans at the time of purchase being less than
10% of the aggregate principal balance of the Mortgage Loans as of the Cut-off
Date.

                  The recitals contained herein shall be taken as statements of
the Depositor and the Trustee assume no responsibility for their correctness.

                  Unless the certificate of authentication hereon has been
executed by the Trustee, by manual signature, this Certificate shall not be
entitled to any benefit under the Agreement or be valid for any purpose.

                                      A-3-5

<PAGE>

                  IN WITNESS WHEREOF, the Trustee has caused this Certificate to
be duly executed.

Dated: February __, 2003
                                            MASTR ASSET BACKED SECURITIES
                                             TRUST 2003-OPT1

                                            WELLS FARGO BANK MINNESOTA,
                                             NATIONAL ASSOCIATION, not in its
                                             individual capacity, but solely as
                                             Trustee

                                            By:______________________________
                                                    Authorized Officer

                          CERTIFICATE OF AUTHENTICATION
                          -----------------------------

         This is one of the Certificates referred to in the within-mentioned
Agreement.

                                            WELLS FARGO BANK MINNESOTA,
                                            NATIONAL ASSOCIATION, as Trustee

                                            By:______________________________
                                                    Authorized Signatory

                                      A-3-6

<PAGE>

                                  ABBREVIATIONS
                                  -------------

The following abbreviations, when used in the inscription on the face of this
instrument, shall be construed as though they were written out in full according
to applicable laws or regulations:

TEN COM - as tenants in common                     UNIF GIFT MIN ACT - Custodian

TEN ENT - as tenants by the entireties             (Cust) (Minor) under
                                                            Uniform Gifts
JT TEN - as joint tenants with right                        to Minors Act
         if survivorship and not as                 _______________
          tenants in common                            (State)

         Additional abbreviations may also be used though not in the above list.

                                   ASSIGNMENT
                                   ----------

                  FOR VALUE RECEIVED, the undersigned hereby sell(s), assign(s)
and transfer(s) unto ___________________________________________________________
________________________________________________________________________________
________________________________________________________________________________
(Please print or typewrite name, address including postal zip code, and Taxpayer
Identification Number of assignee) a Percentage Interest equal to ____%
evidenced by the within Mortgage Pass- Through Certificates and hereby
authorize(s) the registration of transfer of such interest to assignee on the
Certificate Register of the Trust Fund.

         I (we) further direct the Trustee to issue a new Certificate of a like
Percentage Interest and Class to the above named assignee and deliver such
Certificate to the following address:
______________________________________________________________________________
______________________________________________________________________________.

Dated:

                                           _____________________________________
                                           Signature by or on behalf of assignor

                                           _____________________________________
                                           Signature Guaranteed

                                      A-3-7

<PAGE>

                            DISTRIBUTION INSTRUCTIONS

         The assignee should include the following for purposes of distribution:

         Distributions shall be made, 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.

                                      A-3-8

<PAGE>

                                   EXHIBIT A-5
                                   -----------

                          FORM OF CLASS M-3 CERTIFICATE

         UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF
         THE DEPOSITORY TRUST COMPANY, A NEW YORK CORPORATION ("DTC"), TO THE
         TRUSTEE OR ITS AGENT FOR REGISTRATION OF TRANSFER, EXCHANGE, OR
         PAYMENT, AND ANY CERTIFICATE ISSUED IS REGISTERED IN THE NAME OF CEDE &
         CO. OR IN SUCH OTHER NAME AS IS REQUESTED BY AN AUTHORIZED
         REPRESENTATIVE OF DTC (AND ANY PAYMENT IS MADE TO CEDE & CO. OR TO SUCH
         OTHER ENTITY AS IS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC),
         ANY TRANSFER, PLEDGE, OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR
         TO ANY PERSON IS WRONGFUL INASMUCH AS THE REGISTERED OWNER HEREOF, CEDE
         & CO., HAS AN INTEREST HEREIN.

         SOLELY FOR U.S. FEDERAL INCOME TAX PURPOSES, THIS CERTIFICATE IS A
         "REGULAR INTEREST" IN A "REAL ESTATE MORTGAGE INVESTMENT CONDUIT," AS
         THOSE TERMS ARE DEFINED, RESPECTIVELY, IN SECTIONS 860G AND 860D OF THE
         INTERNAL REVENUE CODE OF 1986 (THE "CODE").

         THIS CERTIFICATE IS SUBORDINATE TO THE CLASS A-1 CERTIFICATES, THE
         CLASS A-2 CERTIFICATES, THE CLASS M-1 CERTIFICATES AND THE CLASS M-2
         CERTIFICATES TO THE EXTENT DESCRIBED IN THE POOLING AND SERVICING
         AGREEMENT REFERRED TO HEREIN.

         NO TRANSFER OF THIS CERTIFICATE TO AN EMPLOYEE BENEFIT PLAN OR OTHER
         RETIREMENT ARRANGEMENT SUBJECT TO THE EMPLOYEE RETIREMENT INCOME
         SECURITY ACT OF 1974, AS AMENDED, OR THE CODE WILL BE REGISTERED EXCEPT
         IN COMPLIANCE WITH THE PROCEDURES DESCRIBED HEREIN.

                                      A-4-1

<PAGE>

<TABLE>
<CAPTION>
<S>                                                        <C>
Series:  2003-OPT1                                         Aggregate Certificate Principal Balance of the
                                                           Class M-3 Certificates as of the Issue Date:
Pass-Through Rate: Variable                                $[___]

Cut-off Date and date of Pooling and                       Denomination: $[____]
Servicing Agreement: February 1, 2003
                                                           Master Servicer:  Option One Mortgage
First Distribution Date: March 25, 2003                    Corporation

No. 1                                                      Trustee: Wells Fargo Bank Minnesota,
                                                           National Association

                                                           Issue Date: February [__], 2003

                                                           CUSIP: [____]
</TABLE>

         DISTRIBUTIONS IN REDUCTION OF THE CERTIFICATE PRINCIPAL BALANCE OF THIS
         CERTIFICATE MAY BE MADE MONTHLY AS SET FORTH HEREIN. ACCORDINGLY, THE
         OUTSTANDING CERTIFICATE PRINCIPAL BALANCE HEREOF AT ANY TIME MAY BE
         LESS THAN THE AMOUNT SHOWN ABOVE AS THE DENOMINATION OF THIS
         CERTIFICATE.

                                      A-4-2

<PAGE>

                        MORTGAGE PASS-THROUGH CERTIFICATE

evidencing a beneficial ownership interest in a portion of a Trust Fund (the
"Trust Fund") consisting primarily of a pool of conventional one- to
four-family, fixed-rate and adjustable-rate, first and second lien mortgage
loans (the "Mortgage Loans") formed and sold by

                MORTGAGE ASSET SECURITIZATION TRANSACTIONS, INC.

         THIS CERTIFICATE DOES NOT REPRESENT AN OBLIGATION OF OR INTEREST IN
         MORTGAGE ASSET SECURITIZATION TRANSACTIONS, INC., THE MASTER SERVICER,
         THE TRUSTEE OR ANY OF THEIR RESPECTIVE AFFILIATES. NEITHER THIS
         CERTIFICATE NOR THE UNDERLYING MORTGAGE LOANS ARE GUARANTEED BY ANY
         AGENCY OR INSTRUMENTALITY OF THE UNITED STATES.

                  This certifies that Cede & Co. is the registered owner of a
Percentage Interest (obtained by dividing the denomination of this Certificate
by the aggregate Certificate Principal Balance of the Class M-3 Certificates as
of the Issue Date) in that certain beneficial ownership interest evidenced by
all the Class M-3 Certificates in REMIC II created pursuant to a Pooling and
Servicing Agreement, dated as specified above (the "Agreement"), among Mortgage
Asset Securitization Transactions, Inc. (hereinafter called the "Depositor,"
which term includes any successor entity under the Agreement), the Master
Servicer and the Trustee, a summary of certain of the pertinent provisions of
which is set forth hereafter. To the extent not defined herein, the capitalized
terms used herein have the meanings assigned 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, distributions 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 (a "Distribution Date"), commencing on
the First Distribution Date specified above, to the Person in whose name this
Certificate is registered on the Record Date, in an amount equal to the product
of the Percentage Interest evidenced by this Certificate and the amount required
to be distributed to the Holders of Class M-3 Certificates on such Distribution
Date pursuant to the Agreement.

                  All distributions to the Holder of this Certificate under the
Agreement will be made or caused to be made by the Trustee by wire transfer in
immediately available funds to the account of the Person entitled thereto if
such Person shall have so notified the Trustee in writing at least five Business
Days prior to the Record Date immediately prior to such Distribution Date and is
the registered owner of Class M-3 Certificates the aggregate initial Certificate
Principal Balance of which is in excess of the lesser of (i) $5,000,000 or (ii)
two-thirds of the aggregate initial Certificate Principal Balance of the Class
M-3 Certificates, or otherwise by check mailed by first class mail 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 by the Trustee of the pendency of
such distribution and only upon presentation and surrender

                                      A-4-3

<PAGE>

of this Certificate at the office or agency appointed by the Trustee for that
purpose as provided in the Agreement.

                  The Pass-Through Rate applicable to the calculation of
interest payable with respect to this Certificate on any Distribution Date shall
equal a rate per annum equal to the lesser of (i) the related Formula Rate for
such Distribution Date and (ii) the related Net WAC Pass-Through Rate for such
Distribution Date.

                  This Certificate is one of a duly authorized issue of
Certificates designated as Mortgage Pass-Through Certificates of the Series
specified on the face hereof (herein called the "Certificates") and representing
a Percentage Interest in the Class of Certificates specified on the face hereof
equal to the denomination specified on the face hereof divided by the aggregate
Certificate Principal Balance of the Class of Certificates specified on the face
hereof.

                  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. As provided in the
Agreement, withdrawals from the Collection Account and the Distribution Account
may be made from time to time for purposes other than distributions to
Certificateholders, such purposes including reimbursement of advances made, or
certain expenses incurred, with respect to the Mortgage Loans.

                  The Agreement permits, with certain exceptions therein
provided, the amendment thereof and the modification of the rights and
obligations of the Depositor, the Master Servicer, 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
entitled to at least 66% of the Voting Rights. 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 herefor or in lieu hereof whether or not notation
of such consent is made upon this Certificate. The Agreement also permits the
amendment thereof, in certain limited 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 offices or agencies appointed by the Trustee as provided in
the Agreement, duly endorsed by, or accompanied by an assignment in the form
below or other written instrument of transfer in form satisfactory to the
Trustee duly executed by, the Holder hereof or such Holder's attorney duly
authorized in writing, and thereupon one or more new Certificates of the same
Class in authorized denominations evidencing the same aggregate Percentage
Interest will be issued to the designated transferee or transferees.

                  No transfer of this Certificate to a Plan subject to ERISA or
Section 4975 of the Code, any Person acting, directly or indirectly, on behalf
of any such Plan or any Person using "Plan Assets" to acquire this Certificate
shall be made except in accordance with Section 5.02(c) of the Agreement.

                                      A-4-4

<PAGE>

                  The Certificates are issuable in fully registered form only
without coupons in Classes and denominations representing Percentage Interests
specified in the Agreement. As provided in the Agreement and subject to certain
limitations therein set forth, the Certificates are exchangeable for new
Certificates of the same Class in authorized denominations evidencing the same
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
of Certificates, but the Trustee may require payment of a sum sufficient to
cover any tax or other governmental charge that may be imposed in connection
with any transfer or exchange of Certificates.

                  The Depositor, the Master Servicer, the Trustee and any agent
of the Depositor, the Master Servicer or the Trustee may treat the Person in
whose name this Certificate is registered as the owner hereof for all purposes,
and none of the Depositor, the Master Servicer, the Trustee nor any such agent
shall be affected by notice to the contrary.

                  The obligations created by the Agreement and the Trust Fund
created thereby shall terminate upon payment to the Certificateholders of all
amounts held by the Trustee and required to be paid to them pursuant to the
Agreement following the earlier of (i) the final payment or other liquidation
(or any advance with respect thereto) of the last Mortgage Loan and REO Property
remaining in REMIC I and (ii) the purchase by the party designated in the
Agreement at a price determined as provided in the Agreement from REMIC I of all
the Mortgage Loans and all property acquired in respect of such Mortgage Loans.
The Agreement permits, but does not require, the party designated in the
Agreement to purchase from REMIC I all the 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 right will effect early retirement of the
Certificates; however, such right to purchase is subject to the aggregate Stated
Principal Balance of the Mortgage Loans at the time of purchase being less than
10% of the aggregate principal balance of the Mortgage Loans as of the Cut-off
Date.

                  The recitals contained herein shall be taken as statements of
the Depositor and the Trustee assume no responsibility for their correctness.

                  Unless the certificate of authentication hereon has been
executed by the Trustee, by manual signature, this Certificate shall not be
entitled to any benefit under the Agreement or be valid for any purpose.

                                      A-4-5

<PAGE>

                  IN WITNESS WHEREOF, the Trustee has caused this Certificate to
be duly executed.

Dated: February __, 2003
                                            MASTR ASSET BACKED SECURITIES
                                             TRUST 2003-OPT1

                                            WELLS FARGO BANK MINNESOTA,
                                             NATIONAL ASSOCIATION, not in its
                                             individual capacity, but solely as
                                             Trustee

                                            By:______________________________
                                                    Authorized Officer

                          CERTIFICATE OF AUTHENTICATION
                          -----------------------------

         This is one of the Certificates referred to in the within-mentioned
Agreement.

                                            WELLS FARGO BANK MINNESOTA,
                                            NATIONAL ASSOCIATION, as Trustee

                                            By:______________________________
                                                    Authorized Signatory

                                      A-4-6

<PAGE>

                                  ABBREVIATIONS
                                  -------------

The following abbreviations, when used in the inscription on the face of this
instrument, shall be construed as though they were written out in full according
to applicable laws or regulations:

TEN COM - as tenants in common                     UNIF GIFT MIN ACT - Custodian

TEN ENT - as tenants by the entireties             (Cust) (Minor) under
                                                            Uniform Gifts
JT TEN - as joint tenants with right                        to Minors Act
         if survivorship and not as                 _______________
          tenants in common                            (State)

         Additional abbreviations may also be used though not in the above list.

                                   ASSIGNMENT
                                   ----------

                  FOR VALUE RECEIVED, the undersigned hereby sell(s), assign(s)
and transfer(s) unto ___________________________________________________________
________________________________________________________________________________
________________________________________________________________________________
(Please print or typewrite name, address including postal zip code, and Taxpayer
Identification Number of assignee) a Percentage Interest equal to ____%
evidenced by the within Mortgage Pass- Through Certificates and hereby
authorize(s) the registration of transfer of such interest to assignee on the
Certificate Register of the Trust Fund.

         I (we) further direct the Trustee to issue a new Certificate of a like
Percentage Interest and Class to the above named assignee and deliver such
Certificate to the following address:
______________________________________________________________________________
______________________________________________________________________________.

Dated:

                                           _____________________________________
                                           Signature by or on behalf of assignor

                                           _____________________________________
                                           Signature Guaranteed

                                      A-4-7

<PAGE>

                            DISTRIBUTION INSTRUCTIONS

         The assignee should include the following for purposes of distribution:

         Distributions shall be made, 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.

                                      A-4-8

<PAGE>

                                   EXHIBIT A-6
                                   -----------

                          FORM OF CLASS M-4 CERTIFICATE

         UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF
         THE DEPOSITORY TRUST COMPANY, A NEW YORK CORPORATION ("DTC"), TO THE
         TRUSTEE OR ITS AGENT FOR REGISTRATION OF TRANSFER, EXCHANGE, OR
         PAYMENT, AND ANY CERTIFICATE ISSUED IS REGISTERED IN THE NAME OF CEDE &
         CO. OR IN SUCH OTHER NAME AS IS REQUESTED BY AN AUTHORIZED
         REPRESENTATIVE OF DTC (AND ANY PAYMENT IS MADE TO CEDE & CO. OR TO SUCH
         OTHER ENTITY AS IS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC),
         ANY TRANSFER, PLEDGE, OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR
         TO ANY PERSON IS WRONGFUL INASMUCH AS THE REGISTERED OWNER HEREOF, CEDE
         & CO., HAS AN INTEREST HEREIN.

         SOLELY FOR U.S. FEDERAL INCOME TAX PURPOSES, THIS CERTIFICATE IS A
         "REGULAR INTEREST" IN A "REAL ESTATE MORTGAGE INVESTMENT CONDUIT," AS
         THOSE TERMS ARE DEFINED, RESPECTIVELY, IN SECTIONS 860G AND 860D OF THE
         INTERNAL REVENUE CODE OF 1986 (THE "CODE").

         THIS CERTIFICATE IS SUBORDINATE TO THE CLASS A-1 CERTIFICATES, THE
         CLASS A-2 CERTIFICATES, THE CLASS M-1 CERTIFICATES, THE CLASS M-2
         CERTIFICATES AND THE CLASS M-3 CERTIFICATES TO THE EXTENT DESCRIBED IN
         THE POOLING AND SERVICING AGREEMENT REFERRED TO HEREIN.

         NO TRANSFER OF THIS CERTIFICATE TO AN EMPLOYEE BENEFIT PLAN OR OTHER
         RETIREMENT ARRANGEMENT SUBJECT TO THE EMPLOYEE RETIREMENT INCOME
         SECURITY ACT OF 1974, AS AMENDED, OR THE CODE WILL BE REGISTERED EXCEPT
         IN COMPLIANCE WITH THE PROCEDURES DESCRIBED HEREIN.

                                      A-5-1

<PAGE>

<TABLE>
<CAPTION>
<S>                                                        <C>
Series:  2003-OPT1                                         Aggregate Certificate Principal Balance of the
                                                           Class M-4 Certificates as of the Issue Date:
Pass-Through Rate: Variable                                $[____]

Cut-off Date and date of Pooling and                       Denomination: $[____]
Servicing Agreement: February 1, 2003
                                                           Master Servicer:  Option One Mortgage
First Distribution Date: March 25, 2003                    Corporation

No. 1                                                      Trustee: Wells Fargo Bank Minnesota,
                                                           National Association

                                                           Issue Date: February [__], 2003

                                                           CUSIP: [___]
</TABLE>

         DISTRIBUTIONS IN REDUCTION OF THE CERTIFICATE PRINCIPAL BALANCE OF THIS
         CERTIFICATE MAY BE MADE MONTHLY AS SET FORTH HEREIN. ACCORDINGLY, THE
         OUTSTANDING CERTIFICATE PRINCIPAL BALANCE HEREOF AT ANY TIME MAY BE
         LESS THAN THE AMOUNT SHOWN ABOVE AS THE DENOMINATION OF THIS
         CERTIFICATE.

                                      A-5-2

<PAGE>

                        MORTGAGE PASS-THROUGH CERTIFICATE

evidencing a beneficial ownership interest in a portion of a Trust Fund (the
"Trust Fund") consisting primarily of a pool of conventional one- to
four-family, fixed-rate and adjustable-rate, first and second lien mortgage
loans (the "Mortgage Loans") formed and sold by

                MORTGAGE ASSET SECURITIZATION TRANSACTIONS, INC.

         THIS CERTIFICATE DOES NOT REPRESENT AN OBLIGATION OF OR INTEREST IN
         MORTGAGE ASSET SECURITIZATION TRANSACTIONS, INC., THE MASTER SERVICER,
         THE TRUSTEE OR ANY OF THEIR RESPECTIVE AFFILIATES. NEITHER THIS
         CERTIFICATE NOR THE UNDERLYING MORTGAGE LOANS ARE GUARANTEED BY ANY
         AGENCY OR INSTRUMENTALITY OF THE UNITED STATES.

                  This certifies that Cede & Co. is the registered owner of a
Percentage Interest (obtained by dividing the denomination of this Certificate
by the aggregate Certificate Principal Balance of the Class M-4 Certificates as
of the Issue Date) in that certain beneficial ownership interest evidenced by
all the Class M-4 Certificates in REMIC II created pursuant to a Pooling and
Servicing Agreement, dated as specified above (the "Agreement"), among Mortgage
Asset Securitization Transactions, Inc. (hereinafter called the "Depositor,"
which term includes any successor entity under the Agreement), the Master
Servicer and the Trustee, a summary of certain of the pertinent provisions of
which is set forth hereafter. To the extent not defined herein, the capitalized
terms used herein have the meanings assigned 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, distributions 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 (a "Distribution Date"), commencing on
the First Distribution Date specified above, to the Person in whose name this
Certificate is registered on the Record Date, in an amount equal to the product
of the Percentage Interest evidenced by this Certificate and the amount required
to be distributed to the Holders of Class M-4 Certificates on such Distribution
Date pursuant to the Agreement.

                  All distributions to the Holder of this Certificate under the
Agreement will be made or caused to be made by the Trustee by wire transfer in
immediately available funds to the account of the Person entitled thereto if
such Person shall have so notified the Trustee in writing at least five Business
Days prior to the Record Date immediately prior to such Distribution Date and is
the registered owner of Class M-4 Certificates the aggregate initial Certificate
Principal Balance of which is in excess of the lesser of (i) $5,000,000 or (ii)
two-thirds of the aggregate initial Certificate Principal Balance of the Class
M-4 Certificates, or otherwise by check mailed by first class mail 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 by the Trustee of the pendency of
such distribution and only upon presentation and surrender

                                      A-5-3

<PAGE>

of this Certificate at the office or agency appointed by the Trustee for that
purpose as provided in the Agreement.

                  The Pass-Through Rate applicable to the calculation of
interest payable with respect to this Certificate on any Distribution Date shall
equal a rate per annum equal to the lesser of (i) the related Formula Rate for
such Distribution Date and (ii) the related Net WAC Pass-Through Rate for such
Distribution Date.

                  This Certificate is one of a duly authorized issue of
Certificates designated as Mortgage Pass-Through Certificates of the Series
specified on the face hereof (herein called the "Certificates") and representing
a Percentage Interest in the Class of Certificates specified on the face hereof
equal to the denomination specified on the face hereof divided by the aggregate
Certificate Principal Balance of the Class of Certificates specified on the face
hereof.

                  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. As provided in the
Agreement, withdrawals from the Collection Account and the Distribution Account
may be made from time to time for purposes other than distributions to
Certificateholders, such purposes including reimbursement of advances made, or
certain expenses incurred, with respect to the Mortgage Loans.

                  The Agreement permits, with certain exceptions therein
provided, the amendment thereof and the modification of the rights and
obligations of the Depositor, the Master Servicer, the Trustee, 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 entitled to at least 66% of the Voting Rights. 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 herefor or in lieu hereof whether or not
notation of such consent is made upon this Certificate. The Agreement also
permits the amendment thereof, in certain limited 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 offices or agencies appointed by the Trustee as provided in
the Agreement, duly endorsed by, or accompanied by an assignment in the form
below or other written instrument of transfer in form satisfactory to the
Trustee duly executed by, the Holder hereof or such Holder's attorney duly
authorized in writing, and thereupon one or more new Certificates of the same
Class in authorized denominations evidencing the same aggregate Percentage
Interest will be issued to the designated transferee or transferees.

                  No transfer of this Certificate to a Plan subject to ERISA or
Section 4975 of the Code, any Person acting, directly or indirectly, on behalf
of any such Plan or any Person using "Plan Assets" to acquire this Certificate
shall be made except in accordance with Section 5.02(c) of the Agreement.

                                      A-5-4

<PAGE>

                  The Certificates are issuable in fully registered form only
without coupons in Classes and denominations representing Percentage Interests
specified in the Agreement. As provided in the Agreement and subject to certain
limitations therein set forth, the Certificates are exchangeable for new
Certificates of the same Class in authorized denominations evidencing the same
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
of Certificates, but the Trustee may require payment of a sum sufficient to
cover any tax or other governmental charge that may be imposed in connection
with any transfer or exchange of Certificates.

                  The Depositor, the Master Servicer, the Trustee and any agent
of the Depositor, the Master Servicer or the Trustee may treat the Person in
whose name this Certificate is registered as the owner hereof for all purposes,
and none of the Depositor, the Master Servicer, the Trustee nor any such agent
shall be affected by notice to the contrary.

                  The obligations created by the Agreement and the Trust Fund
created thereby shall terminate upon payment to the Certificateholders of all
amounts held by the Trustee and required to be paid to them pursuant to the
Agreement following the earlier of (i) the final payment or other liquidation
(or any advance with respect thereto) of the last Mortgage Loan and REO Property
remaining in REMIC I and (ii) the purchase by the party designated in the
Agreement at a price determined as provided in the Agreement from REMIC I of all
the Mortgage Loans and all property acquired in respect of such Mortgage Loans.
The Agreement permits, but does not require, the party designated in the
Agreement to purchase from REMIC I all the 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 right will effect early retirement of the
Certificates; however, such right to purchase is subject to the aggregate Stated
Principal Balance of the Mortgage Loans at the time of purchase being less than
10% of the aggregate principal balance of the Mortgage Loans as of the Cut-off
Date.

                  The recitals contained herein shall be taken as statements of
the Depositor and the Trustee assume no responsibility for their correctness.

                  Unless the certificate of authentication hereon has been
executed by the Trustee, by manual signature, this Certificate shall not be
entitled to any benefit under the Agreement or be valid for any purpose.

                                      A-5-5

<PAGE>

                  IN WITNESS WHEREOF, the Trustee has caused this Certificate to
be duly executed.

Dated: February __, 2003
                                            MASTR ASSET BACKED SECURITIES
                                             TRUST 2003-OPT1

                                            WELLS FARGO BANK MINNESOTA,
                                             NATIONAL ASSOCIATION, not in its
                                             individual capacity, but solely as
                                             Trustee

                                            By:______________________________
                                                    Authorized Officer

                          CERTIFICATE OF AUTHENTICATION
                          -----------------------------

         This is one of the Certificates referred to in the within-mentioned
Agreement.

                                            WELLS FARGO BANK MINNESOTA,
                                            NATIONAL ASSOCIATION, as Trustee

                                            By:______________________________
                                                    Authorized Signatory

                                      A-5-6

<PAGE>

                                  ABBREVIATIONS
                                  -------------

The following abbreviations, when used in the inscription on the face of this
instrument, shall be construed as though they were written out in full according
to applicable laws or regulations:

TEN COM - as tenants in common                     UNIF GIFT MIN ACT - Custodian

TEN ENT - as tenants by the entireties             (Cust) (Minor) under
                                                            Uniform Gifts
JT TEN - as joint tenants with right                        to Minors Act
         if survivorship and not as                 _______________
          tenants in common                            (State)

         Additional abbreviations may also be used though not in the above list.

                                   ASSIGNMENT
                                   ----------

                  FOR VALUE RECEIVED, the undersigned hereby sell(s), assign(s)
and transfer(s) unto ___________________________________________________________
________________________________________________________________________________
________________________________________________________________________________
(Please print or typewrite name, address including postal zip code, and Taxpayer
Identification Number of assignee) a Percentage Interest equal to ____%
evidenced by the within Mortgage Pass- Through Certificates and hereby
authorize(s) the registration of transfer of such interest to assignee on the
Certificate Register of the Trust Fund.

         I (we) further direct the Trustee to issue a new Certificate of a like
Percentage Interest and Class to the above named assignee and deliver such
Certificate to the following address:
______________________________________________________________________________
______________________________________________________________________________.

Dated:

                                           _____________________________________
                                           Signature by or on behalf of assignor

                                           _____________________________________
                                           Signature Guaranteed

                                      A-5-7

<PAGE>

                            DISTRIBUTION INSTRUCTIONS

         The assignee should include the following for purposes of distribution:

         Distributions shall be made, 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.

                                      A-5-8

<PAGE>

                                   EXHIBIT A-7
                                   -----------

                         FORM OF CLASS MV-5 CERTIFICATE

         UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF
         THE DEPOSITORY TRUST COMPANY, A NEW YORK CORPORATION ("DTC"), TO THE
         TRUSTEE OR ITS AGENT FOR REGISTRATION OF TRANSFER, EXCHANGE, OR
         PAYMENT, AND ANY CERTIFICATE ISSUED IS REGISTERED IN THE NAME OF CEDE &
         CO. OR IN SUCH OTHER NAME AS IS REQUESTED BY AN AUTHORIZED
         REPRESENTATIVE OF DTC (AND ANY PAYMENT IS MADE TO CEDE & CO. OR TO SUCH
         OTHER ENTITY AS IS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC),
         ANY TRANSFER, PLEDGE, OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR
         TO ANY PERSON IS WRONGFUL INASMUCH AS THE REGISTERED OWNER HEREOF, CEDE
         & CO., HAS AN INTEREST HEREIN.

         SOLELY FOR U.S. FEDERAL INCOME TAX PURPOSES, THIS CERTIFICATE IS A
         "REGULAR INTEREST" IN A "REAL ESTATE MORTGAGE INVESTMENT CONDUIT," AS
         THOSE TERMS ARE DEFINED, RESPECTIVELY, IN SECTIONS 860G AND 860D OF THE
         INTERNAL REVENUE CODE OF 1986 (THE "CODE").

         THIS CERTIFICATE IS SUBORDINATE TO THE CLASS A-1 CERTIFICATES, THE
         CLASS A-2 CERTIFICATES, THE CLASS M-1 CERTIFICATES, THE CLASS M-2
         CERTIFICATES, THE CLASS M-3 CERTIFICATES AND THE CLASS M-4 CERTIFICATES
         TO THE EXTENT DESCRIBED IN THE POOLING AND SERVICING AGREEMENT REFERRED
         TO HEREIN.

         NO TRANSFER OF THIS CERTIFICATE TO AN EMPLOYEE BENEFIT PLAN OR OTHER
         RETIREMENT ARRANGEMENT SUBJECT TO THE EMPLOYEE RETIREMENT INCOME
         SECURITY ACT OF 1974, AS AMENDED, OR THE CODE WILL BE REGISTERED EXCEPT
         IN COMPLIANCE WITH THE PROCEDURES DESCRIBED HEREIN.

                                      A-5-9

<PAGE>

<TABLE>
<CAPTION>
<S>                                                        <C>
Series:  2003-OPT1                                         Aggregate Certificate Principal Balance of the
                                                           Class MV-5 Certificates as of the Issue Date:
Pass-Through Rate: [___]%                                  $[____]

Cut-off Date and date of Pooling and                       Denomination: $[____]
Servicing Agreement: February 1, 2003
                                                           Master Servicer:  Option One Mortgage
First Distribution Date: March 25, 2003                    Corporation

No. 1                                                      Trustee: Wells Fargo Bank Minnesota,
                                                           National Association

                                                           Issue Date: February [__], 2003

                                                           CUSIP: [___]
</TABLE>

         DISTRIBUTIONS IN REDUCTION OF THE CERTIFICATE PRINCIPAL BALANCE OF THIS
         CERTIFICATE MAY BE MADE MONTHLY AS SET FORTH HEREIN. ACCORDINGLY, THE
         OUTSTANDING CERTIFICATE PRINCIPAL BALANCE HEREOF AT ANY TIME MAY BE
         LESS THAN THE AMOUNT SHOWN ABOVE AS THE DENOMINATION OF THIS
         CERTIFICATE.

                                     A-5-10

<PAGE>

                        MORTGAGE PASS-THROUGH CERTIFICATE

evidencing a beneficial ownership interest in a portion of a Trust Fund (the
"Trust Fund") consisting primarily of a pool of conventional one- to
four-family, fixed-rate and adjustable-rate, first and second lien mortgage
loans (the "Mortgage Loans") formed and sold by

                MORTGAGE ASSET SECURITIZATION TRANSACTIONS, INC.

         THIS CERTIFICATE DOES NOT REPRESENT AN OBLIGATION OF OR INTEREST IN
         MORTGAGE ASSET SECURITIZATION TRANSACTIONS, INC., THE MASTER SERVICER,
         THE TRUSTEE OR ANY OF THEIR RESPECTIVE AFFILIATES. NEITHER THIS
         CERTIFICATE NOR THE UNDERLYING MORTGAGE LOANS ARE GUARANTEED BY ANY
         AGENCY OR INSTRUMENTALITY OF THE UNITED STATES.

                  This certifies that Cede & Co. is the registered owner of a
Percentage Interest (obtained by dividing the denomination of this Certificate
by the aggregate Certificate Principal Balance of the Class MV-5 Certificates as
of the Issue Date) in that certain beneficial ownership interest evidenced by
all the Class MV-5 Certificates in REMIC II created pursuant to a Pooling and
Servicing Agreement, dated as specified above (the "Agreement"), among Mortgage
Asset Securitization Transactions, Inc. (hereinafter called the "Depositor,"
which term includes any successor entity under the Agreement), the Master
Servicer and the Trustee, a summary of certain of the pertinent provisions of
which is set forth hereafter. To the extent not defined herein, the capitalized
terms used herein have the meanings assigned 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, distributions 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 (a "Distribution Date"), commencing on
the First Distribution Date specified above, to the Person in whose name this
Certificate is registered on the Record Date, in an amount equal to the product
of the Percentage Interest evidenced by this Certificate and the amount required
to be distributed to the Holders of Class MV-5 Certificates on such Distribution
Date pursuant to the Agreement.

                  All distributions to the Holder of this Certificate under the
Agreement will be made or caused to be made by the Trustee by wire transfer in
immediately available funds to the account of the Person entitled thereto if
such Person shall have so notified the Trustee in writing at least five Business
Days prior to the Record Date immediately prior to such Distribution Date and is
the registered owner of Class MV-5 Certificates the aggregate initial
Certificate Principal Balance of which is in excess of the lesser of (i)
$5,000,000 or (ii) two-thirds of the aggregate initial Certificate Principal
Balance of the Class MV-5 Certificates, or otherwise by check mailed by first
class mail 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 by the
Trustee of the pendency of such distribution and only upon presentation and
surrender

                                     A-5-11

<PAGE>

of this Certificate at the office or agency appointed by the Trustee for that
purpose as provided in the Agreement.

                  The Pass-Through Rate applicable to the calculation of
interest payable with respect to this Certificate on any Distribution Date shall
equal a rate per annum equal to the lesser of (x)(i) [___]% per annum on each
Distribution Date on or prior to the Optional Termination Date and (ii) [___]%
per annum on each Distribution Date after the Optional Termination Date and (y)
the Net WAC Rate for such Distribution Date.

                  This Certificate is one of a duly authorized issue of
Certificates designated as Mortgage Pass-Through Certificates of the Series
specified on the face hereof (herein called the "Certificates") and representing
a Percentage Interest in the Class of Certificates specified on the face hereof
equal to the denomination specified on the face hereof divided by the aggregate
Certificate Principal Balance of the Class of Certificates specified on the face
hereof.

                  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. As provided in the
Agreement, withdrawals from the Collection Account and the Distribution Account
may be made from time to time for purposes other than distributions to
Certificateholders, such purposes including reimbursement of advances made, or
certain expenses incurred, with respect to the Mortgage Loans.

                  The Agreement permits, with certain exceptions therein
provided, the amendment thereof and the modification of the rights and
obligations of the Depositor, the Master Servicer, the Trustee, 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 entitled to at least 66% of the Voting Rights. 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 herefor or in lieu hereof whether or not
notation of such consent is made upon this Certificate. The Agreement also
permits the amendment thereof, in certain limited 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 offices or agencies appointed by the Trustee as provided in
the Agreement, duly endorsed by, or accompanied by an assignment in the form
below or other written instrument of transfer in form satisfactory to the
Trustee duly executed by, the Holder hereof or such Holder's attorney duly
authorized in writing, and thereupon one or more new Certificates of the same
Class in authorized denominations evidencing the same aggregate Percentage
Interest will be issued to the designated transferee or transferees.

                  No transfer of this Certificate to a Plan subject to ERISA or
Section 4975 of the Code, any Person acting, directly or indirectly, on behalf
of any such Plan or any Person using "Plan Assets" to acquire this Certificate
shall be made except in accordance with Section 5.02(c) of the Agreement.

                                     A-5-12

<PAGE>

                  The Certificates are issuable in fully registered form only
without coupons in Classes and denominations representing Percentage Interests
specified in the Agreement. As provided in the Agreement and subject to certain
limitations therein set forth, the Certificates are exchangeable for new
Certificates of the same Class in authorized denominations evidencing the same
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
of Certificates, but the Trustee may require payment of a sum sufficient to
cover any tax or other governmental charge that may be imposed in connection
with any transfer or exchange of Certificates.

                  The Depositor, the Master Servicer, the Trustee and any agent
of the Depositor, the Master Servicer or the Trustee may treat the Person in
whose name this Certificate is registered as the owner hereof for all purposes,
and none of the Depositor, the Master Servicer, the Trustee nor any such agent
shall be affected by notice to the contrary.

                  The obligations created by the Agreement and the Trust Fund
created thereby shall terminate upon payment to the Certificateholders of all
amounts held by the Trustee and required to be paid to them pursuant to the
Agreement following the earlier of (i) the final payment or other liquidation
(or any advance with respect thereto) of the last Mortgage Loan and REO Property
remaining in REMIC I and (ii) the purchase by the party designated in the
Agreement at a price determined as provided in the Agreement from REMIC I of all
the Mortgage Loans and all property acquired in respect of such Mortgage Loans.
The Agreement permits, but does not require, the party designated in the
Agreement to purchase from REMIC I all the 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 right will effect early retirement of the
Certificates; however, such right to purchase is subject to the aggregate Stated
Principal Balance of the Mortgage Loans at the time of purchase being less than
10% of the aggregate principal balance of the Mortgage Loans as of the Cut-off
Date.

                  The recitals contained herein shall be taken as statements of
the Depositor and the Trustee assume no responsibility for their correctness.

                  Unless the certificate of authentication hereon has been
executed by the Trustee, by manual signature, this Certificate shall not be
entitled to any benefit under the Agreement or be valid for any purpose.

                                     A-5-13

<PAGE>

                  IN WITNESS WHEREOF, the Trustee has caused this Certificate to
be duly executed.

Dated: February __, 2003
                                            MASTR ASSET BACKED SECURITIES
                                             TRUST 2003-OPT1

                                            WELLS FARGO BANK MINNESOTA,
                                             NATIONAL ASSOCIATION, not in its
                                             individual capacity, but solely as
                                             Trustee

                                            By:______________________________
                                                    Authorized Officer

                          CERTIFICATE OF AUTHENTICATION
                          -----------------------------

         This is one of the Certificates referred to in the within-mentioned
Agreement.

                                            WELLS FARGO BANK MINNESOTA,
                                            NATIONAL ASSOCIATION, as Trustee

                                            By:______________________________
                                                    Authorized Signatory

                                      A-5-14

<PAGE>

                                  ABBREVIATIONS
                                  -------------

The following abbreviations, when used in the inscription on the face of this
instrument, shall be construed as though they were written out in full according
to applicable laws or regulations:

TEN COM - as tenants in common                     UNIF GIFT MIN ACT - Custodian

TEN ENT - as tenants by the entireties             (Cust) (Minor) under
                                                            Uniform Gifts
JT TEN - as joint tenants with right                        to Minors Act
         if survivorship and not as                 _______________
          tenants in common                            (State)

         Additional abbreviations may also be used though not in the above list.

                                   ASSIGNMENT
                                   ----------

                  FOR VALUE RECEIVED, the undersigned hereby sell(s), assign(s)
and transfer(s) unto ___________________________________________________________
________________________________________________________________________________
________________________________________________________________________________
(Please print or typewrite name, address including postal zip code, and Taxpayer
Identification Number of assignee) a Percentage Interest equal to ____%
evidenced by the within Mortgage Pass- Through Certificates and hereby
authorize(s) the registration of transfer of such interest to assignee on the
Certificate Register of the Trust Fund.

         I (we) further direct the Trustee to issue a new Certificate of a like
Percentage Interest and Class to the above named assignee and deliver such
Certificate to the following address:
______________________________________________________________________________
______________________________________________________________________________.

Dated:

                                           _____________________________________
                                           Signature by or on behalf of assignor

                                           _____________________________________
                                           Signature Guaranteed

                                      A-5-15

<PAGE>

                            DISTRIBUTION INSTRUCTIONS

         The assignee should include the following for purposes of distribution:

         Distributions shall be made, 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.

                                     A-5-16

<PAGE>

                                   EXHIBIT A-8
                                   -----------

                         FORM OF CLASS MF-5 CERTIFICATE

         UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF
         THE DEPOSITORY TRUST COMPANY, A NEW YORK CORPORATION ("DTC"), TO THE
         TRUSTEE OR ITS AGENT FOR REGISTRATION OF TRANSFER, EXCHANGE, OR
         PAYMENT, AND ANY CERTIFICATE ISSUED IS REGISTERED IN THE NAME OF CEDE &
         CO. OR IN SUCH OTHER NAME AS IS REQUESTED BY AN AUTHORIZED
         REPRESENTATIVE OF DTC (AND ANY PAYMENT IS MADE TO CEDE & CO. OR TO SUCH
         OTHER ENTITY AS IS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC),
         ANY TRANSFER, PLEDGE, OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR
         TO ANY PERSON IS WRONGFUL INASMUCH AS THE REGISTERED OWNER HEREOF, CEDE
         & CO., HAS AN INTEREST HEREIN.

         SOLELY FOR U.S. FEDERAL INCOME TAX PURPOSES, THIS CERTIFICATE IS A
         "REGULAR INTEREST" IN A "REAL ESTATE MORTGAGE INVESTMENT CONDUIT," AS
         THOSE TERMS ARE DEFINED, RESPECTIVELY, IN SECTIONS 860G AND 860D OF THE
         INTERNAL REVENUE CODE OF 1986 (THE "CODE").

         THIS CERTIFICATE IS SUBORDINATE TO THE CLASS A-1 CERTIFICATES, THE
         CLASS A-2 CERTIFICATES, THE CLASS M-1 CERTIFICATES, THE CLASS M-2
         CERTIFICATES, THE CLASS M-3 CERTIFICATES AND THE CLASS M-4 CERTIFICATES
         TO THE EXTENT DESCRIBED IN THE POOLING AND SERVICING AGREEMENT REFERRED
         TO HEREIN.

         NO TRANSFER OF THIS CERTIFICATE TO AN EMPLOYEE BENEFIT PLAN OR OTHER
         RETIREMENT ARRANGEMENT SUBJECT TO THE EMPLOYEE RETIREMENT INCOME
         SECURITY ACT OF 1974, AS AMENDED, OR THE CODE WILL BE REGISTERED EXCEPT
         IN COMPLIANCE WITH THE PROCEDURES DESCRIBED HEREIN.

                                     A-5-17

<PAGE>

<TABLE>
<CAPTION>
<S>                                                        <C>
Series:  2003-OPT1                                         Aggregate Certificate Principal Balance of the
                                                           Class MF-5 Certificates as of the Issue Date:
Pass-Through Rate: [___]%                                  $[____]

Cut-off Date and date of Pooling and                       Denomination: $[____]
Servicing Agreement: February 1, 2003
                                                           Master Servicer:  Option One Mortgage
First Distribution Date: March 25, 2003                    Corporation

No. 1                                                      Trustee: Wells Fargo Bank Minnesota,
                                                           National Association

                                                           Issue Date: February [__], 2003

                                                           CUSIP: [___]
</TABLE>

         DISTRIBUTIONS IN REDUCTION OF THE CERTIFICATE PRINCIPAL BALANCE OF THIS
         CERTIFICATE MAY BE MADE MONTHLY AS SET FORTH HEREIN. ACCORDINGLY, THE
         OUTSTANDING CERTIFICATE PRINCIPAL BALANCE HEREOF AT ANY TIME MAY BE
         LESS THAN THE AMOUNT SHOWN ABOVE AS THE DENOMINATION OF THIS
         CERTIFICATE.

                                     A-5-18

<PAGE>

                        MORTGAGE PASS-THROUGH CERTIFICATE

evidencing a beneficial ownership interest in a portion of a Trust Fund (the
"Trust Fund") consisting primarily of a pool of conventional one- to
four-family, fixed-rate and adjustable-rate, first and second lien mortgage
loans (the "Mortgage Loans") formed and sold by

                MORTGAGE ASSET SECURITIZATION TRANSACTIONS, INC.

         THIS CERTIFICATE DOES NOT REPRESENT AN OBLIGATION OF OR INTEREST IN
         MORTGAGE ASSET SECURITIZATION TRANSACTIONS, INC., THE MASTER SERVICER,
         THE TRUSTEE OR ANY OF THEIR RESPECTIVE AFFILIATES. NEITHER THIS
         CERTIFICATE NOR THE UNDERLYING MORTGAGE LOANS ARE GUARANTEED BY ANY
         AGENCY OR INSTRUMENTALITY OF THE UNITED STATES.

                  This certifies that Cede & Co. is the registered owner of a
Percentage Interest (obtained by dividing the denomination of this Certificate
by the aggregate Certificate Principal Balance of the Class MF-5 Certificates as
of the Issue Date) in that certain beneficial ownership interest evidenced by
all the Class MF-5 Certificates in REMIC II created pursuant to a Pooling and
Servicing Agreement, dated as specified above (the "Agreement"), among Mortgage
Asset Securitization Transactions, Inc. (hereinafter called the "Depositor,"
which term includes any successor entity under the Agreement), the Master
Servicer and the Trustee, a summary of certain of the pertinent provisions of
which is set forth hereafter. To the extent not defined herein, the capitalized
terms used herein have the meanings assigned 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, distributions 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 (a "Distribution Date"), commencing on
the First Distribution Date specified above, to the Person in whose name this
Certificate is registered on the Record Date, in an amount equal to the product
of the Percentage Interest evidenced by this Certificate and the amount required
to be distributed to the Holders of Class MF-5 Certificates on such Distribution
Date pursuant to the Agreement.

                  All distributions to the Holder of this Certificate under the
Agreement will be made or caused to be made by the Trustee by wire transfer in
immediately available funds to the account of the Person entitled thereto if
such Person shall have so notified the Trustee in writing at least five Business
Days prior to the Record Date immediately prior to such Distribution Date and is
the registered owner of Class MF-5 Certificates the aggregate initial
Certificate Principal Balance of which is in excess of the lesser of (i)
$5,000,000 or (ii) two-thirds of the aggregate initial Certificate Principal
Balance of the Class MF-5 Certificates, or otherwise by check mailed by first
class mail 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 by the
Trustee of the pendency of such distribution and only upon presentation and
surrender

                                     A-5-19

<PAGE>

of this Certificate at the office or agency appointed by the Trustee for that
purpose as provided in the Agreement.

                  The Pass-Through Rate applicable to the calculation of
interest payable with respect to this Certificate on any Distribution Date shall
equal a rate per annum equal to the lesser of (x)(i) [___]% per annum on each
Distribution Date on or prior to the Optional Termination Date and (ii) [___]%
per annum on each Distribution Date after the Optional Termination Date and (y)
the Net WAC Rate for such Distribution Date.

                  This Certificate is one of a duly authorized issue of
Certificates designated as Mortgage Pass-Through Certificates of the Series
specified on the face hereof (herein called the "Certificates") and representing
a Percentage Interest in the Class of Certificates specified on the face hereof
equal to the denomination specified on the face hereof divided by the aggregate
Certificate Principal Balance of the Class of Certificates specified on the face
hereof.

                  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. As provided in the
Agreement, withdrawals from the Collection Account and the Distribution Account
may be made from time to time for purposes other than distributions to
Certificateholders, such purposes including reimbursement of advances made, or
certain expenses incurred, with respect to the Mortgage Loans.

                  The Agreement permits, with certain exceptions therein
provided, the amendment thereof and the modification of the rights and
obligations of the Depositor, the Master Servicer, the Trustee, 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 entitled to at least 66% of the Voting Rights. 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 herefor or in lieu hereof whether or not
notation of such consent is made upon this Certificate. The Agreement also
permits the amendment thereof, in certain limited 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 offices or agencies appointed by the Trustee as provided in
the Agreement, duly endorsed by, or accompanied by an assignment in the form
below or other written instrument of transfer in form satisfactory to the
Trustee duly executed by, the Holder hereof or such Holder's attorney duly
authorized in writing, and thereupon one or more new Certificates of the same
Class in authorized denominations evidencing the same aggregate Percentage
Interest will be issued to the designated transferee or transferees.

                  No transfer of this Certificate to a Plan subject to ERISA or
Section 4975 of the Code, any Person acting, directly or indirectly, on behalf
of any such Plan or any Person using "Plan Assets" to acquire this Certificate
shall be made except in accordance with Section 5.02(c) of the Agreement.

                                     A-5-20

<PAGE>

                  The Certificates are issuable in fully registered form only
without coupons in Classes and denominations representing Percentage Interests
specified in the Agreement. As provided in the Agreement and subject to certain
limitations therein set forth, the Certificates are exchangeable for new
Certificates of the same Class in authorized denominations evidencing the same
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
of Certificates, but the Trustee may require payment of a sum sufficient to
cover any tax or other governmental charge that may be imposed in connection
with any transfer or exchange of Certificates.

                  The Depositor, the Master Servicer, the Trustee and any agent
of the Depositor, the Master Servicer or the Trustee may treat the Person in
whose name this Certificate is registered as the owner hereof for all purposes,
and none of the Depositor, the Master Servicer, the Trustee nor any such agent
shall be affected by notice to the contrary.

                  The obligations created by the Agreement and the Trust Fund
created thereby shall terminate upon payment to the Certificateholders of all
amounts held by the Trustee and required to be paid to them pursuant to the
Agreement following the earlier of (i) the final payment or other liquidation
(or any advance with respect thereto) of the last Mortgage Loan and REO Property
remaining in REMIC I and (ii) the purchase by the party designated in the
Agreement at a price determined as provided in the Agreement from REMIC I of all
the Mortgage Loans and all property acquired in respect of such Mortgage Loans.
The Agreement permits, but does not require, the party designated in the
Agreement to purchase from REMIC I all the 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 right will effect early retirement of the
Certificates; however, such right to purchase is subject to the aggregate Stated
Principal Balance of the Mortgage Loans at the time of purchase being less than
10% of the aggregate principal balance of the Mortgage Loans as of the Cut-off
Date.

                  The recitals contained herein shall be taken as statements of
the Depositor and the Trustee assume no responsibility for their correctness.

                  Unless the certificate of authentication hereon has been
executed by the Trustee, by manual signature, this Certificate shall not be
entitled to any benefit under the Agreement or be valid for any purpose.

                                     A-5-21

<PAGE>

                  IN WITNESS WHEREOF, the Trustee has caused this Certificate to
be duly executed.

Dated: February __, 2003
                                            MASTR ASSET BACKED SECURITIES
                                             TRUST 2003-OPT1

                                            WELLS FARGO BANK MINNESOTA,
                                             NATIONAL ASSOCIATION, not in its
                                             individual capacity, but solely as
                                             Trustee

                                            By:______________________________
                                                    Authorized Officer

                          CERTIFICATE OF AUTHENTICATION
                          -----------------------------

         This is one of the Certificates referred to in the within-mentioned
Agreement.

                                            WELLS FARGO BANK MINNESOTA,
                                            NATIONAL ASSOCIATION, as Trustee

                                            By:______________________________
                                                    Authorized Signatory

                                      A-5-22

<PAGE>

                                  ABBREVIATIONS
                                  -------------

The following abbreviations, when used in the inscription on the face of this
instrument, shall be construed as though they were written out in full according
to applicable laws or regulations:

TEN COM - as tenants in common                     UNIF GIFT MIN ACT - Custodian

TEN ENT - as tenants by the entireties             (Cust) (Minor) under
                                                            Uniform Gifts
JT TEN - as joint tenants with right                        to Minors Act
         if survivorship and not as                 _______________
          tenants in common                            (State)

         Additional abbreviations may also be used though not in the above list.

                                   ASSIGNMENT
                                   ----------

                  FOR VALUE RECEIVED, the undersigned hereby sell(s), assign(s)
and transfer(s) unto ___________________________________________________________
________________________________________________________________________________
________________________________________________________________________________
(Please print or typewrite name, address including postal zip code, and Taxpayer
Identification Number of assignee) a Percentage Interest equal to ____%
evidenced by the within Mortgage Pass- Through Certificates and hereby
authorize(s) the registration of transfer of such interest to assignee on the
Certificate Register of the Trust Fund.

         I (we) further direct the Trustee to issue a new Certificate of a like
Percentage Interest and Class to the above named assignee and deliver such
Certificate to the following address:
______________________________________________________________________________
______________________________________________________________________________.

Dated:

                                           _____________________________________
                                           Signature by or on behalf of assignor

                                           _____________________________________
                                           Signature Guaranteed

                                      A-5-23

<PAGE>

                            DISTRIBUTION INSTRUCTIONS

         The assignee should include the following for purposes of distribution:

         Distributions shall be made, 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.

                                     A-5-24

<PAGE>

                                   EXHIBIT A-9
                                   -----------

                          FORM OF CLASS CE CERTIFICATE

         SOLELY FOR U.S. FEDERAL INCOME TAX PURPOSES, THIS CERTIFICATE IS A
         "REGULAR INTEREST" IN A "REAL ESTATE MORTGAGE INVESTMENT CONDUIT," AS
         THOSE TERMS ARE DEFINED, RESPECTIVELY, IN SECTIONS 860G AND 860D OF THE
         INTERNAL REVENUE CODE OF 1986 (THE "CODE").

         THIS CERTIFICATE IS SUBORDINATE TO THE CLASS A-1 CERTIFICATES, THE
         CLASS A-2 CERTIFICATES, THE CLASS M-1 CERTIFICATES, THE CLASS M-2
         CERTIFICATES, THE CLASS M-3 CERTIFICATES, THE CLASS M-4 CERTIFICATES,
         THE CLASS MV-5 CERTIFICATES AND THE CLASS MF-5 CERTIFICATES TO THE
         EXTENT DESCRIBED IN THE POOLING AND SERVICING 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 THAT 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.

         NO TRANSFER OF THIS CERTIFICATE TO AN EMPLOYEE BENEFIT PLAN OR OTHER
         RETIREMENT ARRANGEMENT SUBJECT TO THE EMPLOYEE RETIREMENT INCOME
         SECURITY ACT OF 1974, AS AMENDED, OR THE CODE WILL BE REGISTERED EXCEPT
         IN COMPLIANCE WITH THE PROCEDURES DESCRIBED HEREIN.

                                     A-5-25

<PAGE>

<TABLE>
<CAPTION>
<S>                                                        <C>
Series 2003-OPT1                                           Aggregate Certificate Principal Balance of the
                                                           Class CE Certificates as of the Issue Date:
Pass-Through Rate: Variable                                $[____]

Cut-off Date and date of Pooling and                       Denomination: $[____]
Servicing Agreement: February 1, 2003
                                                           Master Servicer:  Option One Mortgage
First Distribution Date: March 25, 2003                    Corporation

No. 1                                                      Trustee: Wells Fargo Bank Minnesota,
                                                           National Association
Aggregate Notional Amount of the Class
CE Certificates as of the Issue Date: $[_____]             Issue Date: February [__], 2003

Notional Amount: $[____]
</TABLE>

         DISTRIBUTIONS IN REDUCTION OF THE CERTIFICATE PRINCIPAL BALANCE OF THIS
         CERTIFICATE MAY BE MADE MONTHLY AS SET FORTH HEREIN. ACCORDINGLY, THE
         OUTSTANDING CERTIFICATE PRINCIPAL BALANCE HEREOF AT ANY TIME MAY BE
         LESS THAN THE AMOUNT SHOWN ABOVE AS THE DENOMINATION OF THIS
         CERTIFICATE.

                                     A-5-26

<PAGE>

                        MORTGAGE PASS-THROUGH CERTIFICATE

evidencing a beneficial ownership interest in a portion of a Trust Fund (the
"Trust Fund") consisting primarily of a pool of conventional one- to
four-family, fixed-rate and adjustable-rate, first and second lien mortgage
loans (the "Mortgage Loans") formed and sold by

                MORTGAGE ASSET SECURITIZATION TRANSACTIONS, INC.

         THIS CERTIFICATE DOES NOT REPRESENT AN OBLIGATION OF OR INTEREST IN
         MORTGAGE ASSET SECURITIZATION TRANSACTIONS, INC., THE MASTER SERVICER,
         THE TRUSTEE OR ANY OF THEIR RESPECTIVE AFFILIATES. NEITHER THIS
         CERTIFICATE NOR THE UNDERLYING MORTGAGE LOANS ARE GUARANTEED BY ANY
         AGENCY OR INSTRUMENTALITY OF THE UNITED STATES.

                  This certifies that [_______] is the registered owner of a
Percentage Interest (obtained by dividing the denomination of this Certificate
by the aggregate Certificate Principal Balance of the Class CE Certificates as
of the Issue Date) in that certain beneficial ownership interest evidenced by
all the Class CE Certificates in REMIC II created pursuant to a Pooling and
Servicing Agreement, dated as specified above (the "Agreement"), among Mortgage
Asset Securitization Transactions, Inc. (hereinafter called the "Depositor,"
which term includes any successor entity under the Agreement), the Master
Servicer and the Trustee, a summary of certain of the pertinent provisions of
which is set forth hereafter. To the extent not defined herein, the capitalized
terms used herein have the meanings assigned 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, distributions 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 (a "Distribution Date"), commencing on
the First Distribution Date specified above, to the Person in whose name this
Certificate is registered on the Record Date, in an amount equal to the product
of the Percentage Interest evidenced by this Certificate and the amount required
to be distributed to the Holders of Class CE Certificates on such Distribution
Date pursuant to the Agreement.

                  All distributions to the Holder of this Certificate under the
Agreement will be made or caused to be made by the Trustee by wire transfer in
immediately available funds to the account of the Person entitled thereto if
such Person shall have so notified the Trustee in writing at least five Business
Days prior to the Record Date immediately prior to such Distribution Date and is
the registered owner of Class CE Certificates the aggregate initial Certificate
Principal Balance of which is in excess of the lesser of (i) $5,000,000 or (ii)
two-thirds of the aggregate initial Certificate Principal Balance of the Class
CE Certificates, or otherwise by check mailed by first class mail 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 by the Trustee of the pendency of such
distribution and only upon presentation and surrender of this Certificate at the
office or agency appointed by the Trustee for that purpose as provided in the
Agreement.

                                     A-5-27

<PAGE>

                  This Certificate is one of a duly authorized issue of
Certificates designated as Mortgage Pass-Through Certificates of the Series
specified on the face hereof (herein called the "Certificates") and representing
a Percentage Interest in the Class of Certificates specified on the face hereof
equal to the denomination specified on the face hereof divided by the aggregate
Certificate Principal Balance of the Class of Certificates specified on the face
hereof.

                  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. As provided in the
Agreement, withdrawals from the Collection Account and the Distribution Account
may be made from time to time for purposes other than distributions to
Certificateholders, such purposes including reimbursement of advances made, or
certain expenses incurred, with respect to the Mortgage Loans.

                  The Agreement permits, with certain exceptions therein
provided, the amendment thereof and the modification of the rights and
obligations of the Depositor, the Master Servicer, 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
entitled to at least 66% of the Voting Rights. 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 herefor or in lieu hereof whether or not notation
of such consent is made upon this Certificate. The Agreement also permits the
amendment thereof, in certain limited 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 offices or agencies appointed by the Trustee as provided in
the Agreement, duly endorsed by, or accompanied by an assignment in the form
below or other written instrument of transfer in form satisfactory to the
Trustee duly executed by, the Holder hereof or such Holder's attorney duly
authorized in writing, and thereupon one or more new Certificates of the same
Class in authorized denominations evidencing the same aggregate Percentage
Interest will be issued to the designated transferee or transferees.

                  No transfer of this Certificate shall be made unless the
transfer is made pursuant to an effective registration statement under the
Securities Act of 1933, as amended (the "1933 Act"), and an effective
registration or qualification under applicable state securities laws, or is made
in a transaction that does not require such registration or qualification. In
the event that such a transfer of this Certificate is to be made without
registration or qualification, the Trustee shall require receipt of (i) if such
transfer is purportedly being made in reliance upon Rule 144A under the 1933
Act, written certifications from the Holder of the Certificate desiring to
effect the transfer, and from such Holder's prospective transferee,
substantially in the forms attached to the Agreement as Exhibit F-1, and (ii) in
all other cases, an Opinion of Counsel satisfactory to it that such transfer may
be made without such registration or qualification (which Opinion of Counsel
shall not be an expense of the Trust Fund or of the Depositor, the Trustee or
the Master Servicer in their respective capacities as such), together with
copies of the written certification(s) of the Holder of the Certificate desiring
to effect the transfer and/or such Holder's prospective transferee upon which
such Opinion of Counsel is based. None of the Depositor or the Trustee is
obligated to register or qualify the Class of

                                     A-5-28

<PAGE>

Certificates specified on the face hereof under the 1933 Act or any other
securities law or to take any action not otherwise required under the Agreement
to permit the transfer of such Certificates without registration or
qualification. Any Holder desiring to effect a transfer of this Certificate
shall be required to indemnify the Trustee, the Depositor and the Master
Servicer 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.

                  No transfer of this Certificate to a Plan subject to ERISA or
Section 4975 of the Code, any Person acting, directly or indirectly, on behalf
of any such Plan or any Person using "Plan Assets" to acquire this Certificate
shall be made except in accordance with Section 5.02(c) of the Agreement.

                  The Certificates are issuable in fully registered form only
without coupons in Classes and denominations representing Percentage Interests
specified in the Agreement. As provided in the Agreement and subject to certain
limitations therein set forth, the Certificates are exchangeable for new
Certificates of the same Class in authorized denominations evidencing the same
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
of Certificates, but the Trustee may require payment of a sum sufficient to
cover any tax or other governmental charge that may be imposed in connection
with any transfer or exchange of Certificates.

                  The Depositor, the Master Servicer, the Trustee and any agent
of the Depositor, the Master Servicer or the Trustee may treat the Person in
whose name this Certificate is registered as the owner hereof for all purposes,
and none of the Depositor, the Master Servicer, the Trustee nor any such agent
shall be affected by notice to the contrary.

                  The obligations created by the Agreement and the Trust Fund
created thereby shall terminate upon payment to the Certificateholders of all
amounts held by the Trustee and required to be paid to them pursuant to the
Agreement following the earlier of (i) the final payment or other liquidation
(or any advance with respect thereto) of the last Mortgage Loan and REO Property
remaining in REMIC I and (ii) the purchase by the party designated in the
Agreement at a price determined as provided in the Agreement from REMIC I of all
the Mortgage Loans and all property acquired in respect of such Mortgage Loans.
The Agreement permits, but does not require, the party designated in the
Agreement to purchase from REMIC I all the 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 right will effect early retirement of the
Certificates; however, such right to purchase is subject to the aggregate Stated
Principal Balance of the Mortgage Loans at the time of purchase being less than
10% of the aggregate principal balance of the Mortgage Loans as of the Cut-off
Date.

                  The recitals contained herein shall be taken as statements of
the Depositor and the Trustee assume no responsibility for their correctness.

                  Unless the certificate of authentication hereon has been
executed by the Trustee, by manual signature, this Certificate shall not be
entitled to any benefit under the Agreement or be valid for any purpose.

                                     A-5-29

<PAGE>

                  IN WITNESS WHEREOF, the Trustee has caused this Certificate to
be duly executed.

Dated: February __, 2003
                                            MASTR ASSET BACKED SECURITIES
                                             TRUST 2003-OPT1

                                            WELLS FARGO BANK MINNESOTA,
                                             NATIONAL ASSOCIATION, not in its
                                             individual capacity, but solely as
                                             Trustee

                                            By:______________________________
                                                    Authorized Officer

                          CERTIFICATE OF AUTHENTICATION
                          -----------------------------

         This is one of the Certificates referred to in the within-mentioned
Agreement.

                                            WELLS FARGO BANK MINNESOTA,
                                            NATIONAL ASSOCIATION, as Trustee

                                            By:______________________________
                                                    Authorized Signatory

                                      A-5-30

<PAGE>

                                  ABBREVIATIONS
                                  -------------

The following abbreviations, when used in the inscription on the face of this
instrument, shall be construed as though they were written out in full according
to applicable laws or regulations:

TEN COM - as tenants in common                     UNIF GIFT MIN ACT - Custodian

TEN ENT - as tenants by the entireties             (Cust) (Minor) under
                                                            Uniform Gifts
JT TEN - as joint tenants with right                        to Minors Act
         if survivorship and not as                 _______________
          tenants in common                            (State)

         Additional abbreviations may also be used though not in the above list.

                                   ASSIGNMENT
                                   ----------

                  FOR VALUE RECEIVED, the undersigned hereby sell(s), assign(s)
and transfer(s) unto ___________________________________________________________
________________________________________________________________________________
________________________________________________________________________________
(Please print or typewrite name, address including postal zip code, and Taxpayer
Identification Number of assignee) a Percentage Interest equal to ____%
evidenced by the within Mortgage Pass- Through Certificates and hereby
authorize(s) the registration of transfer of such interest to assignee on the
Certificate Register of the Trust Fund.

         I (we) further direct the Trustee to issue a new Certificate of a like
Percentage Interest and Class to the above named assignee and deliver such
Certificate to the following address:
______________________________________________________________________________
______________________________________________________________________________.

Dated:

                                           _____________________________________
                                           Signature by or on behalf of assignor

                                           _____________________________________
                                           Signature Guaranteed

                                      A-5-31

<PAGE>

                            DISTRIBUTION INSTRUCTIONS

         The assignee should include the following for purposes of distribution:

         Distributions shall be made, 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.

                                     A-5-32

<PAGE>

                                  EXHIBIT A-10
                                  ------------

                           FORM OF CLASS P CERTIFICATE

         SOLELY FOR U.S. FEDERAL INCOME TAX PURPOSES, THIS CERTIFICATE IS A
         "REGULAR INTEREST" IN A "REAL ESTATE MORTGAGE INVESTMENT CONDUIT," AS
         THOSE TERMS ARE DEFINED, RESPECTIVELY, IN SECTIONS 860G AND 860D OF THE
         INTERNAL REVENUE CODE OF 1986 (THE "CODE").

         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 THAT 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.

         NO TRANSFER OF THIS CERTIFICATE TO AN EMPLOYEE BENEFIT PLAN OR OTHER
         RETIREMENT ARRANGEMENT SUBJECT TO THE EMPLOYEE RETIREMENT INCOME
         SECURITY ACT OF 1974, AS AMENDED, OR THE CODE WILL BE REGISTERED EXCEPT
         IN COMPLIANCE WITH THE PROCEDURES DESCRIBED HEREIN.

                                      A-6-1

<PAGE>

<TABLE>
<CAPTION>
<S>                                                        <C>
Series:  2003-OPT1                                         Aggregate Certificate Principal Balance of the
                                                           Class P Certificates as of the Issue Date:
Cut-off Date and date of Pooling and                       $100.00
Servicing Agreement: February 1, 2003
                                                           Denomination: $100.00
First Distribution Date: March 25, 2003
                                                           Master Servicer:  Option One Mortgage
No. 1                                                      Corporation

                                                           Trustee: Wells Fargo Bank Minnesota,
                                                           National Association

                                                           Issue Date: February [__], 2003
</TABLE>

                  DISTRIBUTIONS IN REDUCTION OF THE CERTIFICATE PRINCIPAL
                  BALANCE OF THIS CERTIFICATE MAY BE MADE MONTHLY AS SET FORTH
                  HEREIN. ACCORDINGLY, THE OUTSTANDING CERTIFICATE PRINCIPAL
                  BALANCE HEREOF AT ANY TIME MAY BE LESS THAN THE AMOUNT SHOWN
                  ABOVE AS THE DENOMINATION OF THIS CERTIFICATE.

                                      A-6-2

<PAGE>

                        MORTGAGE PASS-THROUGH CERTIFICATE

evidencing a beneficial ownership interest in a portion of a Trust Fund (the
"Trust Fund") consisting primarily of a pool of conventional one- to
four-family, fixed-rate and adjustable-rate, first and second lien mortgage
loans (the "Mortgage Loans") formed and sold by

                MORTGAGE ASSET SECURITIZATION TRANSACTIONS, INC.

         THIS CERTIFICATE DOES NOT REPRESENT AN OBLIGATION OF OR INTEREST IN
         MORTGAGE ASSET SECURITIZATION TRANSACTIONS, INC., THE MASTER SERVICER,
         THE TRUSTEE OR ANY OF THEIR RESPECTIVE AFFILIATES. NEITHER THIS
         CERTIFICATE NOR THE UNDERLYING MORTGAGE LOANS ARE GUARANTEED BY ANY
         AGENCY OR INSTRUMENTALITY OF THE UNITED STATES.

                  This certifies that [_______] is the registered owner of a
Percentage Interest (obtained by dividing the denomination of this Certificate
by the aggregate Certificate Principal Balance of the Class P Certificates as of
the Issue Date) in that certain beneficial ownership interest evidenced by all
the Class P Certificates in REMIC II created pursuant to a Pooling and Servicing
Agreement, dated as specified above (the "Agreement"), among Mortgage Asset
Securitization Transactions, Inc. (hereinafter called the "Depositor," which
term includes any successor entity under the Agreement), the Master Servicer and
the Trustee, a summary of certain of the pertinent provisions of which is set
forth hereafter. To the extent not defined herein, the capitalized terms used
herein have the meanings assigned 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, distributions 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 (a "Distribution Date"), commencing on
the First Distribution Date specified above, to the Person in whose name this
Certificate is registered on the Record Date, in an amount equal to the product
of the Percentage Interest evidenced by this Certificate and the amount required
to be distributed to the Holders of Class P Certificates on such Distribution
Date pursuant to the Agreement.

                  All distributions to the Holder of this Certificate under the
Agreement will be made or caused to be made by the Trustee by wire transfer in
immediately available funds to the account of the Person entitled thereto if
such Person shall have so notified the Trustee in writing at least five Business
Days prior to the Record Date immediately prior to such Distribution Date and is
the registered owner of Class P Certificates the aggregate initial Certificate
Principal Balance of which is in excess of the lesser of (i) $5,000,000 or (ii)
two-thirds of the aggregate initial Certificate Principal Balance of the Class P
Certificates, or otherwise by check mailed by first class mail 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 by the Trustee of the pendency of such
distribution and only upon presentation and surrender of this Certificate at the
office or agency appointed by the Trustee for that purpose as provided in the
Agreement.

                                      A-6-3

<PAGE>

                  This Certificate is one of a duly authorized issue of
Certificates designated as Mortgage Pass-Through Certificates of the Series
specified on the face hereof (herein called the "Certificates") and representing
a Percentage Interest in the Class of Certificates specified on the face hereof
equal to the denomination specified on the face hereof divided by the aggregate
Certificate Principal Balance of the Class of Certificates specified on the face
hereof.

                  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. As provided in the
Agreement, withdrawals from the Collection Account and the Distribution Account
may be made from time to time for purposes other than distributions to
Certificateholders, such purposes including reimbursement of advances made, or
certain expenses incurred, with respect to the Mortgage Loans.

                  The Agreement permits, with certain exceptions therein
provided, the amendment thereof and the modification of the rights and
obligations of the Depositor, the Master Servicer, 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
entitled to at least 66% of the Voting Rights. 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 herefor or in lieu hereof whether or not notation
of such consent is made upon this Certificate. The Agreement also permits the
amendment thereof, in certain limited 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 offices or agencies appointed by the Trustee as provided in
the Agreement, duly endorsed by, or accompanied by an assignment in the form
below or other written instrument of transfer in form satisfactory to the
Trustee duly executed by, the Holder hereof or such Holder's attorney duly
authorized in writing, and thereupon one or more new Certificates of the same
Class in authorized denominations evidencing the same aggregate Percentage
Interest will be issued to the designated transferee or transferees.

                  No transfer of this Certificate shall be made unless the
transfer is made pursuant to an effective registration statement under the
Securities Act of 1933, as amended (the "1933 Act"), and an effective
registration or qualification under applicable state securities laws, or is made
in a transaction that does not require such registration or qualification. In
the event that such a transfer of this Certificate is to be made without
registration or qualification, the Trustee shall require receipt of (i) if such
transfer is purportedly being made in reliance upon Rule 144A under the 1933
Act, written certifications from the Holder of the Certificate desiring to
effect the transfer, and from such Holder's prospective transferee,
substantially in the forms attached to the Agreement as Exhibit F-1, and (ii) in
all other cases, an Opinion of Counsel satisfactory to it that such transfer may
be made without such registration or qualification (which Opinion of Counsel
shall not be an expense of the Trust Fund or of the Depositor, the Trustee or
the Master Servicer in their respective capacities as such), together with
copies of the written certification(s) of the Holder of the Certificate desiring
to effect the transfer and/or such Holder's prospective transferee upon which
such Opinion of Counsel is based. None of the Depositor or the Trustee is
obligated to register or qualify the Class of

                                      A-6-4

<PAGE>

Certificates specified on the face hereof under the 1933 Act or any other
securities law or to take any action not otherwise required under the Agreement
to permit the transfer of such Certificates without registration or
qualification. Any Holder desiring to effect a transfer of this Certificate
shall be required to indemnify the Trustee, the Depositor and the Master
Servicer 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.

                  No transfer of this Certificate to a Plan subject to ERISA or
Section 4975 of the Code, any Person acting, directly or indirectly, on behalf
of any such Plan or any Person using "Plan Assets" to acquire this Certificate
shall be made except in accordance with Section 5.02(c) of the Agreement.

                  The Certificates are issuable in fully registered form only
without coupons in Classes and denominations representing Percentage Interests
specified in the Agreement. As provided in the Agreement and subject to certain
limitations therein set forth, the Certificates are exchangeable for new
Certificates of the same Class in authorized denominations evidencing the same
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
of Certificates, but the Trustee may require payment of a sum sufficient to
cover any tax or other governmental charge that may be imposed in connection
with any transfer or exchange of Certificates.

                  The Depositor, the Master Servicer, the Trustee and any agent
of the Depositor, the Master Servicer or the Trustee may treat the Person in
whose name this Certificate is registered as the owner hereof for all purposes,
and none of the Depositor, the Master Servicer, the Trustee nor any such agent
shall be affected by notice to the contrary.

                  The obligations created by the Agreement and the Trust Fund
created thereby shall terminate upon payment to the Certificateholders of all
amounts held by the Trustee and required to be paid to them pursuant to the
Agreement following the earlier of (i) the final payment or other liquidation
(or any advance with respect thereto) of the last Mortgage Loan and REO Property
remaining in REMIC I and (ii) the purchase by the party designated in the
Agreement at a price determined as provided in the Agreement from REMIC I of all
the Mortgage Loans and all property acquired in respect of such Mortgage Loans.
The Agreement permits, but does not require, the party designated in the
Agreement to purchase from REMIC I all the 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 right will effect early retirement of the
Certificates; however, such right to purchase is subject to the aggregate Stated
Principal Balance of the Mortgage Loans at the time of purchase being less than
10% of the aggregate principal balance of the Mortgage Loans as of the Cut-off
Date.

                  The recitals contained herein shall be taken as statements of
the Depositor and the Trustee assume no responsibility for their correctness.

                  Unless the certificate of authentication hereon has been
executed by the Trustee, by manual signature, this Certificate shall not be
entitled to any benefit under the Agreement or be valid for any purpose.

                                      A-6-5

<PAGE>

                  IN WITNESS WHEREOF, the Trustee has caused this Certificate to
be duly executed.

Dated: February __, 2003
                                            MASTR ASSET BACKED SECURITIES
                                             TRUST 2003-OPT1

                                            WELLS FARGO BANK MINNESOTA,
                                             NATIONAL ASSOCIATION, not in its
                                             individual capacity, but solely as
                                             Trustee

                                            By:______________________________
                                                    Authorized Officer

                          CERTIFICATE OF AUTHENTICATION
                          -----------------------------

         This is one of the Certificates referred to in the within-mentioned
Agreement.

                                            WELLS FARGO BANK MINNESOTA,
                                            NATIONAL ASSOCIATION, as Trustee

                                            By:______________________________
                                                    Authorized Signatory

                                      A-6-6

<PAGE>

                                  ABBREVIATIONS
                                  -------------

The following abbreviations, when used in the inscription on the face of this
instrument, shall be construed as though they were written out in full according
to applicable laws or regulations:

TEN COM - as tenants in common                     UNIF GIFT MIN ACT - Custodian

TEN ENT - as tenants by the entireties             (Cust) (Minor) under
                                                            Uniform Gifts
JT TEN - as joint tenants with right                        to Minors Act
         if survivorship and not as                 _______________
          tenants in common                            (State)

         Additional abbreviations may also be used though not in the above list.

                                   ASSIGNMENT
                                   ----------

                  FOR VALUE RECEIVED, the undersigned hereby sell(s), assign(s)
and transfer(s) unto ___________________________________________________________
________________________________________________________________________________
________________________________________________________________________________
(Please print or typewrite name, address including postal zip code, and Taxpayer
Identification Number of assignee) a Percentage Interest equal to ____%
evidenced by the within Mortgage Pass- Through Certificates and hereby
authorize(s) the registration of transfer of such interest to assignee on the
Certificate Register of the Trust Fund.

         I (we) further direct the Trustee to issue a new Certificate of a like
Percentage Interest and Class to the above named assignee and deliver such
Certificate to the following address:
______________________________________________________________________________
______________________________________________________________________________.

Dated:

                                           _____________________________________
                                           Signature by or on behalf of assignor

                                           _____________________________________
                                           Signature Guaranteed

                                      A-6-7

<PAGE>

                            DISTRIBUTION INSTRUCTIONS

         The assignee should include the following for purposes of distribution:

         Distributions shall be made, 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.

                                      A-6-8

<PAGE>

                                  EXHIBIT A-11
                                  ------------

                           FORM OF CLASS R CERTIFICATE

         THIS CERTIFICATE MAY NOT BE TRANSFERRED TO A NON-UNITED STATES PERSON.

         SOLELY FOR U.S. FEDERAL INCOME TAX PURPOSES, THIS CERTIFICATE IS A
         "RESIDUAL INTEREST" IN A "REAL ESTATE MORTGAGE INVESTMENT CONDUIT"
         ("REMIC"), AS THOSE TERMS ARE DEFINED, RESPECTIVELY, IN SECTIONS 860G
         AND 860D OF THE INTERNAL REVENUE CODE OF 1986 (THE "CODE").

         ANY RESALE, TRANSFER OR OTHER DISPOSITION OF THIS CERTIFICATE MAY BE
         MADE ONLY IN ACCORDANCE WITH THE PROVISIONS OF SECTION 5.02 OF THE
         POOLING AND SERVICING 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 THAT 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.

         NO TRANSFER OF THIS CERTIFICATE TO AN EMPLOYEE BENEFIT PLAN OR OTHER
         RETIREMENT ARRANGEMENT SUBJECT TO THE EMPLOYEE RETIREMENT INCOME
         SECURITY ACT OF 1974, AS AMENDED, OR THE CODE WILL BE REGISTERED EXCEPT
         IN COMPLIANCE WITH THE PROCEDURES DESCRIBED HEREIN.

         ANY RESALE, TRANSFER OR OTHER DISPOSITION OF THIS CERTIFICATE MAY BE
         MADE ONLY IF THE PROPOSED TRANSFEREE PROVIDES (I) AN AFFIDAVIT TO THE
         TRUSTEE THAT (A) SUCH TRANSFEREE IS NOT (1) THE UNITED STATES OR ANY
         POSSESSION THEREOF, ANY STATE OR POLITICAL SUBDIVISION THEREOF, ANY
         FOREIGN GOVERNMENT, ANY INTERNATIONAL ORGANIZATION, OR ANY AGENCY OR
         INSTRUMENTALITY OF ANY OF THE FOREGOING, (2) ANY ORGANIZATION (OTHER
         THAN A COOPERATIVE DESCRIBED IN SECTION 521 OF THE CODE) THAT IS EXEMPT
         FROM THE TAX IMPOSED BY CHAPTER 1 OF THE CODE UNLESS SUCH ORGANIZATION
         IS SUBJECT TO THE TAX IMPOSED BY SECTION 511 OF THE CODE, (3) ANY
         ORGANIZATION DESCRIBED IN SECTION 1381(A)(2)(C) OF THE CODE (ANY SUCH
         PERSON DESCRIBED IN THE FOREGOING CLAUSES (1), (2) OR

                                      A-7-1

<PAGE>

         (3) SHALL HEREINAFTER BE REFERRED TO AS A "DISQUALIFIED ORGANIZATION")
         OR (4) AN AGENT OF A DISQUALIFIED ORGANIZATION AND (B) NO PURPOSE OF
         SUCH TRANSFER IS TO IMPEDE THE ASSESSMENT OR COLLECTION OF TAX, AND
         (II) SUCH TRANSFEREE SATISFIES CERTAIN ADDITIONAL CONDITIONS RELATING
         TO THE FINANCIAL CONDITION OF THE PROPOSED TRANSFEREE. NOTWITHSTANDING
         THE REGISTRATION IN THE CERTIFICATE REGISTER OF ANY TRANSFER, SALE OR
         OTHER DISPOSITION OF THIS CERTIFICATE TO A DISQUALIFIED ORGANIZATION OR
         AN AGENT OF A DISQUALIFIED ORGANIZATION, SUCH REGISTRATION SHALL BE
         DEEMED TO BE OF NO LEGAL FORCE OR EFFECT WHATSOEVER AND SUCH PERSON
         SHALL NOT BE DEEMED TO BE A CERTIFICATEHOLDER FOR ANY PURPOSE
         HEREUNDER, INCLUDING, BUT NOT LIMITED TO, THE RECEIPT OF DISTRIBUTIONS
         ON THIS CERTIFICATE. EACH HOLDER OF THIS CERTIFICATE BY ACCEPTANCE
         HEREOF SHALL BE DEEMED TO HAVE CONSENTED TO THE PROVISIONS OF THIS
         PARAGRAPH AND THE PROVISIONS OF SECTION 5.02(D) OF THE POOLING AND
         SERVICING AGREEMENT REFERRED TO HEREIN. ANY PERSON THAT IS A
         DISQUALIFIED ORGANIZATION IS PROHIBITED FROM ACQUIRING BENEFICIAL
         OWNERSHIP OF THIS CERTIFICATE.

<TABLE>
<CAPTION>
<S>                                                        <C>
Series:  2003-OPT1                                         Aggregate Percentage Interest of the Class R
                                                           Certificates as of the Issue Date: 100.00%
Cut-off Date and date of Pooling and
Servicing Agreement: February 1, 2003                      Master Servicer:  Option One Mortgage
                                                           Corporation
First Distribution Date: March 25, 2003
                                                           Trustee: Wells Fargo Bank Minnesota,
No.1                                                       National Association

                                                           Issue Date: February [__], 2003
</TABLE>

                                      A-7-2

<PAGE>

                        MORTGAGE PASS-THROUGH CERTIFICATE

evidencing a beneficial ownership interest in a portion of a Trust Fund (the
"Trust Fund") consisting primarily of a pool of conventional one- to
four-family, fixed-rate and adjustable-rate, first and second lien mortgage
loans (the "Mortgage Loans") formed and sold by

                MORTGAGE ASSET SECURITIZATION TRANSACTIONS, INC.

         THIS CERTIFICATE DOES NOT REPRESENT AN OBLIGATION OF OR INTEREST IN
         MORTGAGE ASSET SECURITIZATION TRANSACTIONS, INC., THE MASTER SERVICER,
         THE TRUSTEE OR ANY OF THEIR RESPECTIVE AFFILIATES. NEITHER THIS
         CERTIFICATE NOR THE UNDERLYING MORTGAGE LOANS ARE GUARANTEED BY ANY
         AGENCY OR INSTRUMENTALITY OF THE UNITED STATES.

                  This certifies that [_______] is the registered owner of a
Percentage Interest (as specified above) in that certain beneficial ownership
interest evidenced by all the Certificates of the Class to which this
Certificate belongs created pursuant to a Pooling and Servicing Agreement, dated
as specified above (the "Agreement"), among Mortgage Asset Securitization
Transactions, Inc. (hereinafter called the "Depositor," which term includes any
successor entity under the Agreement), the Master Servicer and the Trustee, a
summary of certain of the pertinent provisions of which is set forth hereafter.
To the extent not defined herein, the capitalized terms used herein have the
meanings assigned 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, distributions 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 (a "Distribution Date"), commencing on
the First Distribution Date specified above, to the Person in whose name this
Certificate is registered on the Record Date, in an amount equal to the product
of the Percentage Interest evidenced by this Certificate and the amount required
to be distributed to the Holders of Class R Certificates on such Distribution
Date pursuant to the Agreement.

                  All distributions to the Holder of this Certificate under the
Agreement will be made or caused to be made by the Trustee by wire transfer in
immediately available funds to the account of the Person entitled thereto if
such Person shall have so notified the Trustee in writing at least five Business
Days prior to the Record Date immediately prior to such Distribution Date and is
the registered owner of Class R Certificates the aggregate initial Certificate
Principal Balance of which is in excess of the lesser of (i) $5,000,000 or (ii)
two-thirds of the aggregate initial Certificate Principal Balance of the Class R
Certificates, or otherwise by check mailed by first class mail 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 by the Trustee of the pendency of such
distribution and only upon presentation and surrender of this Certificate at the
office or agency appointed by the Trustee for that purpose as provided in the
Agreement.

                                      A-7-3

<PAGE>

                  This Certificate is one of a duly authorized issue of
Certificates designated as Mortgage Pass-Through Certificates of the Series
specified on the face hereof (herein called the "Certificates") and representing
a Percentage Interest in the Class of Certificates specified on the face hereof.

                  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. As provided in the
Agreement, withdrawals from the Collection Account and the Distribution Account
may be made from time to time for purposes other than distributions to
Certificateholders, such purposes including reimbursement of advances made, or
certain expenses incurred, with respect to the Mortgage Loans.

                  The Agreement permits, with certain exceptions therein
provided, the amendment thereof and the modification of the rights and
obligations of the Depositor, the Master Servicer, the Trustee 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 entitled to at least 66% of the Voting Rights. 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 herefor or in lieu hereof whether or not
notation of such consent is made upon this Certificate. The Agreement also
permits the amendment thereof, in certain limited 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 offices or agencies appointed by the Trustee as provided in
the Agreement, duly endorsed by, or accompanied by an assignment in the form
below or other written instrument of transfer in form satisfactory to the
Trustee duly executed by, the Holder hereof or such Holder's attorney duly
authorized in writing, and thereupon one or more new Certificates of the same
Class in authorized denominations evidencing the same aggregate Percentage
Interest will be issued to the designated transferee or transferees.

                  No transfer of this Certificate shall be made unless the
transfer is made pursuant to an effective registration statement under the
Securities Act of 1933, as amended (the "1933 Act"), and an effective
registration or qualification under applicable state securities laws, or is made
in a transaction that does not require such registration or qualification. In
the event that such a transfer of this Certificate is to be made without
registration or qualification, the Trustee shall require receipt of (i) if such
transfer is purportedly being made in reliance upon Rule 144A under the 1933
Act, written certifications from the Holder of the Certificate desiring to
effect the transfer, and from such Holder's prospective transferee,
substantially in the forms attached to the Agreement as Exhibit F-1, and (ii) in
all other cases, an Opinion of Counsel satisfactory to it that such transfer may
be made without such registration or qualification (which Opinion of Counsel
shall not be an expense of the Trust Fund or of the Depositor, the Trustee or
the Master Servicer in their respective capacities as such), together with
copies of the written certification(s) of the Holder of the Certificate desiring
to effect the transfer and/or such Holder's prospective transferee upon which
such Opinion of Counsel is based. Neither the Depositor nor the Trustee is
obligated to register or qualify the Class of

                                      A-7-4

<PAGE>

Certificates specified on the face hereof under the 1933 Act or any other
securities law or to take any action not otherwise required under the Agreement
to permit the transfer of such Certificates without registration or
qualification. Any Holder desiring to effect a transfer of this Certificate
shall be required to indemnify the Trustee, the Depositor and the Master
Servicer 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.

                  No transfer of this Certificate to a Plan subject to ERISA or
Section 4975 of the Code, any Person acting, directly or indirectly, on behalf
of any such Plan or any Person using "Plan Assets" to acquire this Certificate
shall be made except in accordance with Section 5.02(c) of the Agreement.

                  The Certificates are issuable in fully registered form only
without coupons in Classes and denominations representing Percentage Interests
specified in the Agreement. As provided in the Agreement and subject to certain
limitations therein set forth, the Certificates are exchangeable for new
Certificates of the same Class in authorized denominations evidencing the same
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
of Certificates, but the Trustee may require payment of a sum sufficient to
cover any tax or other governmental charge that may be imposed in connection
with any transfer or exchange of Certificates.

                  Prior to registration of any transfer, sale or other
disposition of this Certificate, the proposed transferee shall provide to the
Trustee (i) an affidavit to the effect that such transferee is any Person other
than a Disqualified Organization or the agent (including a broker, nominee or
middleman) of a Disqualified Organization, and (ii) a certificate that
acknowledges that (A) the Class R Certificates have been designated as a
residual interest in a REMIC, (B) it will include in its income a PRO RATA share
of the net income of the Trust Fund and that such income may be an "excess
inclusion," as defined in the Code, that, with certain exceptions, cannot be
offset by other losses or benefits from any tax exemption, and (C) it expects to
have the financial means to satisfy all of its tax obligations including those
relating to holding the Class R Certificates. Notwithstanding the registration
in the Certificate Register of any transfer, sale or other disposition of this
Certificate to a Disqualified Organization or an agent (including a broker,
nominee or middleman) of a Disqualified Organization, such registration shall be
deemed to be of no legal force or effect whatsoever and such Person shall not be
deemed to be a Certificateholder for any purpose, including, but not limited to,
the receipt of distributions in respect of this Certificate.

                  The Holder of this Certificate, by its acceptance hereof,
shall be deemed to have consented to the provisions of Section 5.02 of the
Agreement and to any amendment of the Agreement deemed necessary by counsel of
the Depositor to ensure that the transfer of this Certificate to any Person
other than a Permitted Transferee or any other Person will not cause the Trust
Fund to cease to qualify as a REMIC or cause the imposition of a tax upon the
REMIC.

                  The Depositor, the Master Servicer, the Trustee and any agent
of the Depositor, the Master Servicer or the Trustee may treat the Person in
whose name this Certificate is registered as the owner hereof for all purposes,
and none of the Depositor, the Master Servicer, the Trustee nor any such agent
shall be affected by notice to the contrary.

                                      A-7-5

<PAGE>

                  The obligations created by the Agreement and the Trust Fund
created thereby shall terminate upon payment to the Certificateholders of all
amounts held by the Trustee and required to be paid to them pursuant to the
Agreement following the earlier of (i) the final payment or other liquidation
(or any advance with respect thereto) of the last Mortgage Loan and REO Property
remaining in REMIC I and (ii) the purchase by the party designated in the
Agreement at a price determined as provided in the Agreement from REMIC I of all
the Mortgage Loans and all property acquired in respect of such Mortgage Loans.
The Agreement permits, but does not require, the party designated in the
Agreement to purchase from REMIC I all the 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 right will effect early retirement of the
Certificates; however, such right to purchase is subject to the aggregate Stated
Principal Balance of the Mortgage Loans at the time of purchase being less than
10% of the aggregate principal balance of the Mortgage Loans as of the Cut-off
Date.

                  The recitals contained herein shall be taken as statements of
the Depositor and the Trustee assumes no responsibility for their correctness.

                  Unless the certificate of authentication hereon has been
executed by the Trustee, by manual signature, this Certificate shall not be
entitled to any benefit under the Agreement or be valid for any purpose.

                                      A-7-6

<PAGE>

                  IN WITNESS WHEREOF, the Trustee has caused this Certificate to
be duly executed.

Dated: February __, 2003
                                            MASTR ASSET BACKED SECURITIES
                                             TRUST 2003-OPT1

                                            WELLS FARGO BANK MINNESOTA,
                                             NATIONAL ASSOCIATION, not in its
                                             individual capacity, but solely as
                                             Trustee

                                            By:______________________________
                                                    Authorized Officer

                          CERTIFICATE OF AUTHENTICATION
                          -----------------------------

         This is one of the Certificates referred to in the within-mentioned
Agreement.

                                            WELLS FARGO BANK MINNESOTA,
                                            NATIONAL ASSOCIATION, as Trustee

                                            By:______________________________
                                                    Authorized Signatory

                                      A-7-7

<PAGE>

                                  ABBREVIATIONS
                                  -------------

The following abbreviations, when used in the inscription on the face of this
instrument, shall be construed as though they were written out in full according
to applicable laws or regulations:

TEN COM - as tenants in common                     UNIF GIFT MIN ACT - Custodian

TEN ENT - as tenants by the entireties             (Cust) (Minor) under
                                                            Uniform Gifts
JT TEN - as joint tenants with right                        to Minors Act
         if survivorship and not as                 _______________
          tenants in common                            (State)

         Additional abbreviations may also be used though not in the above list.

                                   ASSIGNMENT
                                   ----------

                  FOR VALUE RECEIVED, the undersigned hereby sell(s), assign(s)
and transfer(s) unto ___________________________________________________________
________________________________________________________________________________
________________________________________________________________________________
(Please print or typewrite name, address including postal zip code, and Taxpayer
Identification Number of assignee) a Percentage Interest equal to ____%
evidenced by the within Mortgage Pass- Through Certificates and hereby
authorize(s) the registration of transfer of such interest to assignee on the
Certificate Register of the Trust Fund.

         I (we) further direct the Trustee to issue a new Certificate of a like
Percentage Interest and Class to the above named assignee and deliver such
Certificate to the following address:
______________________________________________________________________________
______________________________________________________________________________.

Dated:

                                           _____________________________________
                                           Signature by or on behalf of assignor

                                           _____________________________________
                                           Signature Guaranteed

                                      A-7-8

<PAGE>

                            DISTRIBUTION INSTRUCTIONS

         The assignee should include the following for purposes of distribution:

         Distributions shall be made, 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.

                                      A-7-9

<PAGE>

                                    EXHIBIT B
                                    ---------

                                   [Reserved]

                                       B-1

<PAGE>

                                   EXHIBIT C-1
                                   -----------

                     FORM OF TRUSTEE'S INITIAL CERTIFICATION

                                                              [Date]

Mortgage Asset Securitization Transactions, Inc.
1285 Avenue of the Americas
New York, New York 10019

Option One Mortgage Corporation
3 Ada
Irvine, California 92618

                  Re:      Pooling and Servicing Agreement, dated as of February
                           1, 2003, among Mortgage Asset Securitization
                           Transactions, Inc., Option One Mortgage Corporation
                           and Wells Fargo Bank Minnesota, National Association,
                           Mortgage Pass-Through Certificates, Series 2003-OPT1
                           -----------------------------------------------------

Ladies and Gentlemen:

         Attached is the Trustee's preliminary exception report delivered in
accordance with Section 2.02 of the referenced Pooling and Servicing Agreement
(the "Pooling and Servicing Agreement"). Capitalized terms used but not
otherwise defined herein shall have the meanings set forth in the Pooling and
Servicing Agreement.

         The Trustee has made no independent examination of any documents
contained in each Mortgage File beyond the review specifically required in the
Pooling and Servicing Agreement. The Trustee makes no representations as to (i)
the validity, legality, sufficiency, enforceability or genuineness of any of the
documents contained in the Mortgage File pertaining to the Mortgage Loans
identified on the Mortgage Loan Schedule, (ii) the collectability, insurability,
effectiveness or suitability of any such Mortgage Loan or (iii) whether any
Mortgage File included any of the documents specified in clause (vi) of Section
2.01 of the Pooling and Servicing Agreement.

                                      C-1-1

<PAGE>

                  Capitalized words and phrases used herein shall have the
respective meanings assigned to them in the Pooling and Servicing Agreement.
This Certificate is qualified in all respects by the terms of said Pooling and
Servicing Agreement.

                                                   WELLS FARGO BANK MINNESOTA,
                                                    NATIONAL ASSOCIATION

                                                   By:__________________________
                                                   Name:
                                                   Title:

                                      C-1-2

<PAGE>

                                   EXHIBIT C-2
                                   -----------

                      FORM OF TRUSTEE'S FINAL CERTIFICATION

                                                        [Date]

Mortgage Asset Securitization Transactions, Inc.
1285 Avenue of the Americas
New York, New York 10019

Option One Mortgage Corporation
3 Ada
Irvine, California 92618

                  Re:      Pooling and Servicing Agreement, dated as of February
                           1, 2003, among Mortgage Asset Securitization
                           Transactions, Inc., Option One Mortgage Corporation
                           and Wells Fargo Bank Minnesota, National Association,
                           Mortgage Pass-Through Certificates, Series 2003-OPT1
                           -----------------------------------------------------

Ladies and Gentlemen:

         In accordance with Section 2.02 of the Pooling and Servicing Agreement,
the undersigned, as Trustee, hereby certifies that as to each Mortgage Loan
listed in the Mortgage Loan Schedule (other than any Mortgage loan paid in full
or listed on Schedule I hereto) it (or its custodian) has received the
applicable documents listed in Section 2.01 of the Pooling and Servicing
Agreement.

         The undersigned hereby certifies that as to each Mortgage Loan
identified on the Mortgage Loan Schedule, other than any Mortgage Loan listed on
Schedule I hereto, it has reviewed the documents listed above and has determined
that each such document appears to be complete and, based on an examination of
such documents, the information set forth in the Mortgage Loan Schedule is
correct.

         The Trustee has made no independent examination of any documents
contained in each Mortgage File beyond the review specifically required in the
Pooling and Servicing Agreement. The Trustee makes no representations as to (i)
the validity, legality, sufficiency, enforceability or genuineness of any of the
documents contained in the Mortgage File pertaining to the Mortgage Loans
identified on the Mortgage Loan Schedule, (ii) the collectability, insurability,
effectiveness or suitability of any such Mortgage Loan or (iii) whether any
Mortgage File included any of the documents specified in clause (vi) of Section
2.01 of the Pooling and Servicing Agreement.

                                      C-2-1

<PAGE>

                  Capitalized words and phrases used herein shall have the
respective meanings assigned to them in the Pooling and Servicing Agreement.
This Certificate is qualified in all respects by the terms of said Pooling and
Servicing Agreement.

                                                    WELLS FARGO BANK MINNESOTA,
                                                     NATIONAL ASSOCIATION

                                                    By:_________________________
                                                    Name:
                                                    Title:

                                      C-2-2

<PAGE>

                                   EXHIBIT C-3

                        FORM OF RECEIPT OF MORTGAGE NOTE

Mortgage Asset Securitization Transactions, Inc.
1285 Avenue of the Americas
New York, New York 10019

Option One Mortgage Acceptance Corporation
3 Ada
Irvine, California 92618

                  Re:      Pooling and Servicing Agreement, dated as of February
                           1, 2003, among Mortgage Asset Securitization
                           Transactions, Inc., Option One Mortgage Corporation
                           and Wells Fargo Bank Minnesota, National Association,
                           Mortgage Pass-Through Certificates, Series 2003-OPT1
                           -----------------------------------------------------

Ladies and Gentlemen:

         Pursuant to Section 2.01 of the Pooling and Servicing Agreement, dated
as of February 1, 2003, among Mortgage Asset Securitization Transactions, Inc.
as Depositor, Option One Mortgage Corporation as Master Servicer and Wells Fargo
Bank Minnesota, National Association. as Trustee (the "Trustee"), we hereby
acknowledge the receipt of the original Mortgage Notes (a copy of which is
attached hereto as Exhibit 1) with any exceptions thereto listed on Exhibit 2.

                                        WELLS FARGO BANK MINNESOTA, NATIONAL
                                        ASSOCIATION,
                                        as Trustee

                                        By:_______________________________
                                        Name:
                                        Title:

                                      C-2-3

<PAGE>

                                    EXHIBIT D
                                    ---------

                    FORM OF MORTGAGE LOAN PURCHASE AGREEMENT

                                       D-1

<PAGE>

                        MORTGAGE LOAN PURCHASE AGREEMENT

                  This is a Mortgage Loan Purchase Agreement (this "Agreement"),
dated February 24, 2003, among UBS Warburg Real Estate Securities Inc., a
Delaware corporation (the "Seller"), Mortgage Asset Securitization Transactions,
Inc., a Delaware corporation (the "Purchaser") and Option One Mortgage
Corporation, a California corporation (the "Originator").

                              Preliminary Statement
                              ---------------------

                  The Seller intends to sell the Mortgage Loans (as hereinafter
identified) and the Cap Contract and all of the Seller rights under the PMI
Policy to the Purchaser on the terms and subject to the conditions set forth in
this Agreement. The Purchaser intends to deposit the Mortgage Loans into a
mortgage pool comprising the Trust Fund. The Trust Fund will be evidenced by a
single series of mortgage pass-through certificates designated as Series
2003-OPT1 (the "Certificates"). The Certificates will consist of eleven classes
of certificates. The Certificates will be issued pursuant to a Pooling and
Servicing Agreement for Series 2003-OPT1, dated as of February 1, 2003 (the
"Pooling and Servicing Agreement"), among the Depositor as depositor, the
Originator as master servicer (in such capacity, the "Master Servicer") and
Wells Fargo Bank Minnesota, National Association as trustee (the "Trustee").
Capitalized terms used but not defined herein shall have the meanings set forth
in the Pooling and Servicing Agreement.

                  The parties hereto agree as follows:

                  SECTION 1. AGREEMENT TO PURCHASE. The Seller agrees to sell
and the Purchaser agrees to purchase, on or before February 27, 2003 (the
"Closing Date"), (i) certain fixed-rate and adjustable-rate conventional, one-
to four-family, residential mortgage loans (the "Mortgage Loans"), having an
aggregate principal balance as of the close of business on February 1, 2003,
(the "Cut-off Date") of approximately $1,464,001,447.20 (the "Closing Balance"),
after giving effect to all payments due on the Mortgage Loans on or before the
Cut-off Date, whether or not received including the right to any Prepayment
Charges payable by the related Mortgagors in connection with any Principal
Prepayments on the Mortgage Loans and (ii) the Seller's rights under the PMI
Policy.

                  SECTION 2. MORTGAGE LOAN SCHEDULE. The Purchaser and the
Seller have agreed upon which of the mortgage loans owned by the Seller are to
be purchased by the Purchaser pursuant to this Agreement and the Seller will
prepare or cause to be prepared on or prior to the Closing Date a final schedule
(the "Closing Schedule") that shall describe such Mortgage Loans and set forth
all of the Mortgage Loans to be purchased under this Agreement, including the
Prepayment Charges. The Closing Schedule will conform to the requirements set
forth in this Agreement and to the definitions of "Mortgage Loan Schedule" and
"Prepayment Charge Schedule" under the Pooling and Servicing Agreement. The
Closing Schedule shall be used as the Mortgage Loan Schedule and Prepayment
Charge Schedule under the Pooling and Servicing Agreement.

<PAGE>

                  SECTION 3.        CONSIDERATION.

                  (a) In consideration for the Mortgage Loans to be purchased
hereunder, the Purchaser shall, as described in Section 8, pay to or upon the
order of the Seller in immediately available funds an amount (the "Purchase
Price") equal to the net sale proceeds of the Certificates.

                  (b) The Purchaser or any assignee, transferee or designee of
the Purchaser shall be entitled to all scheduled payments of principal due after
the Cut-off Date, all other payments of principal due and collected after the
Cut-off Date, and all payments of interest on the Mortgage Loans allocable to
the period after the Cut-off Date. All scheduled payments of principal and
interest due on or before the Cut-off Date and collected after the Cut-off Date
shall belong to the Seller.

                  (c) Pursuant to the Pooling and Servicing Agreement, the
Purchaser will assign all of its right, title and interest in and to the
Mortgage Loans, together with its rights under this Agreement, to the Trustee
for the benefit of the Certificateholders.

                  SECTION 4.        TRANSFER OF THE MORTGAGE LOANS.

                  (a) POSSESSION OF MORTGAGE FILES. The Seller does hereby sell,
transfer, assign, set over and convey to the Purchaser, without recourse but
subject to the terms of this Agreement, all of its right, title and interest in,
to and under the Mortgage Loans, including the related Prepayment Charges and
the Seller's rights under the PMI Policy. The contents of each Mortgage File not
delivered to the Purchaser or to any assignee, transferee or designee of the
Purchaser on or prior to the Closing Date are and shall be held in trust by the
Seller for the benefit of the Purchaser or any assignee, transferee or designee
of the Purchaser. Upon the sale of the Mortgage Loans, the ownership of each
Mortgage Note, the related Mortgage and the other contents of the related
Mortgage File is vested in the Purchaser and the ownership of all records and
documents with respect to the related Mortgage Loan prepared by or that come
into the possession of the Seller on or after the Closing Date shall immediately
vest in the Purchaser and shall be delivered immediately to the Purchaser or as
otherwise directed by the Purchaser.

                  (b) DELIVERY OF MORTGAGE LOAN DOCUMENTS. The Seller will, on
or prior to the Closing Date, deliver or cause to be delivered to the Purchaser
or any assignee, transferee or designee of the Purchaser each of the following
documents for each Mortgage Loan:

                  (i) the original Mortgage Note, endorsed in blank or in the
         following form: "Pay to the order of Wells Fargo Bank Minnesota,
         National Association, as Trustee under the applicable agreement,
         without recourse," with all prior and intervening endorsements showing
         a complete chain of endorsement from the originator to the Person so
         endorsing to the Trustee;

                  (ii) the original Mortgage with evidence of recording thereon,
         and the original recorded power of attorney, if the Mortgage was
         executed pursuant to a power of attorney, with evidence of recording
         thereon;

                  (iii) an original Assignment in blank;

                                       -2-

<PAGE>

                  (iv) the original recorded Assignment or Assignments showing a
         complete chain of assignment from the originator to the Person
         assigning the Mortgage to the Trustee as contemplated by the
         immediately preceding clause (iii);

                  (v) the original or copies of each assumption, modification,
         written assurance or substitution agreement, if any; and

                  (vi) the original lender's title insurance policy, together
         with all endorsements or riders that were issued with or subsequent to
         the issuance of such policy, insuring the priority of the Mortgage as a
         first lien on the Mortgaged Property represented therein as a fee
         interest vested in the Mortgagor, or in the event such original title
         policy is unavailable, a written commitment or uniform binder or
         preliminary report of title issued by the title insurance or escrow
         company.

                  With respect to a maximum of approximately 2.0% of the
Mortgage Loans, by outstanding principal balance of the Mortgage Loans as of the
Cut-off Date, if any original Mortgage Note referred to in Section 4(b)(i) above
cannot be located, the obligations of the Seller to deliver such documents shall
be deemed to be satisfied upon delivery to the Purchaser of a photocopy of such
Mortgage Note, if available, with a lost note affidavit substantially in the
form of Exhibit K to the Pooling and Servicing Agreement. If any of the original
Mortgage Notes for which a lost note affidavit was delivered to the Purchaser is
subsequently located, such original Mortgage Note shall be delivered to the
Purchaser within three Business Days.

                  The Originator shall promptly (within sixty Business Days
following the later of the Closing Date and the date of receipt by the
Originator of the recording information for a Mortgage, but in no event later
than ninety days following the Closing Date) submit or cause to be submitted for
recording, at no expense to the Purchaser, in the appropriate public office for
real property records, each Assignment referred to in Section 4(b)(iii) and (iv)
above and in connection therewith, the Originator shall execute each original
Assignment in the following form: "Wells Fargo Bank Minnesota, National
Association, as Trustee under the applicable agreement." In the event that any
such Assignment is lost or returned unrecorded because of a defect therein, the
Originator shall promptly prepare or cause to be prepared a substitute
Assignment or cure or cause to be cured such defect, as the case may be, and
thereafter cause each such Assignment to be duly recorded.

                  Notwithstanding the foregoing, the Assignments of Mortgage
shall not be required to be submitted for recording (except with respect to any
Mortgage Loan located in Maryland) unless such failure to record would result in
a withdrawal or a downgrading by any Rating Agency of the rating on any Class of
Certificates; provided, however, each Assignment shall be submitted for
recording by the Originator, in the manner described above, at no expense to the
Purchaser, upon the earliest to occur of: (i) reasonable direction by the
Holders of Certificates entitled to at least 25% of the Voting Rights or the
NIMS Insurer, (ii) the occurrence of a Master Servicer Event of Default, (iii)
the occurrence of a bankruptcy, insolvency or foreclosure relating to the
Originator, (iv) the occurrence of a servicing transfer as described in Section
7.02 of the Pooling and Servicing Agreement, (v) upon receipt of notice from the
Master Servicer, the occurrence of a bankruptcy, insolvency or foreclosure
relating to the Mortgagor under the related Mortgage and (vi) upon receipt of
notice from the Master Servicer, any Mortgage Loan that is 90 days or more
delinquent. Upon

                                       -3-

<PAGE>

the occurrence of one of the events set forth in the immediately preceding
sentence, the Originator shall deliver such Assignments for recording as
provided above, promptly and in any event within 30 days following receipt of
notice by the Originator.

                  If any of the documents referred to in Sections 4(b)(ii),
(iii) or (iv) above has, as of the Closing Date, been submitted for recording
but either (x) has not been returned from the applicable public recording office
or (y) has been lost or such public recording office has retained the original
of such document, the obligations of the Seller to deliver such documents shall
be deemed to be satisfied upon (1) delivery to the Purchaser of a copy of each
such document certified by the Originator in the case of (x) above or the
applicable public recording office in the case of (y) above to be a true and
complete copy of the original that was submitted for recording and (2) if such
copy is certified by the Originator, delivery to the Purchaser promptly upon
receipt thereof of either the original or a copy of such document certified by
the applicable public recording office to be a true and complete copy of the
original. Notice shall be provided to the Trustee and the Rating Agencies by the
Originator if delivery pursuant to clause (2) above will be made more than 180
days after the Closing Date.

                  If the original lender's title insurance policy was not
delivered pursuant to Section 4(b)(vi) above, the Seller shall deliver or cause
to be delivered to the Purchaser, promptly after receipt thereof, the original
lender's title insurance policy. The Seller shall deliver or cause to be
delivered to the Purchaser promptly upon receipt thereof any other original
documents constituting a part of a Mortgage File received with respect to any
Mortgage Loan, including, but not limited to, any original documents evidencing
an assumption or modification of any Mortgage Loan.

                  Each original document relating to a Mortgage Loan which is
not delivered to the Purchaser or its assignee, transferee or designee, if held
by the Seller, shall be so held for the benefit of the Purchaser, its assignee,
transferee or designee.

                  (c) ACCEPTANCE OF MORTGAGE LOANS. The documents delivered
pursuant to Section 4(b) hereof shall be reviewed by the Purchaser or any
assignee, transferee or designee of the Purchaser at any time before or after
the Closing Date (and with respect to each document permitted to be delivered
after the Closing Date, within seven days of its delivery) to ascertain that all
required documents have been executed and received and that such documents
relate to the Mortgage Loans identified on the Mortgage Loan Schedule.

                  (d) TRANSFER OF INTEREST IN AGREEMENTS. The Purchaser has the
right to assign its interest under this Agreement, in whole or in part, to the
Trustee, as may be required to effect the purposes of the Pooling and Servicing
Agreement, without the consent of the Seller, and the assignee shall succeed to
the rights and obligations hereunder of the Purchaser. Any expense reasonably
incurred by or on behalf of the Purchaser or the Trustee in connection with
enforcing any obligations of the Seller under this Agreement will be promptly
reimbursed by the Seller.

                  (e) EXAMINATION OF MORTGAGE FILES. Prior to the Closing Date,
the Seller shall either (i) deliver in escrow to the Purchaser, or to any
assignee, transferee or designee of the Purchaser for examination, the Mortgage
File pertaining to each Mortgage Loan or (ii) make such Mortgage Files available
to the Purchaser or to any assignee, transferee or designee of the Purchaser

                                       -4-

<PAGE>

for examination. Such examination may be made by the Purchaser or the Trustee,
and their respective designees, upon reasonable notice to the Seller during
normal business hours before the Closing Date and within 60 days after the
Closing Date. If any such person makes such examination prior to the Closing
Date and identifies any Mortgage Loans that do not conform to the requirements
of the Purchaser as described in this Agreement, such Mortgage Loans shall be
deleted from the Closing Schedule. The Purchaser may, at its option and without
notice to the Seller, purchase all or part of the Mortgage Loans without
conducting any partial or complete examination. The fact that the Purchaser or
any person has conducted or has failed to conduct any partial or complete
examination of the Mortgage Files shall not affect the rights of the Purchaser
or any assignee, transferee or designee of the Purchaser to demand repurchase or
other relief as provided herein or under the Pooling and Servicing Agreement.

                  SECTION 5.        REPRESENTATIONS, WARRANTIES AND COVENANTS OF
                                    THE SELLER AND THE ORIGINATOR.

                  (a) The Seller hereby represents and warrants to the
Originator and the Purchaser, as of the date hereof and as of the Closing Date,
and covenants, that:

                  (i) The Seller is duly organized, validly existing and in good
standing as a corporation under the laws of the State of Delaware with full
corporate power and authority to conduct its business as presently conducted by
it to the extent material to the consummation of the transactions contemplated
herein. The Seller has the full corporate power and authority to own the
Mortgage Loans and to transfer and convey the Mortgage Loans to the Purchaser
and has the full corporate power and authority to execute and deliver, engage in
the transactions contemplated by, and perform and observe the terms and
conditions of this Agreement.

                  (ii) The Seller has duly authorized the execution, delivery
and performance of this Agreement, has duly executed and delivered this
Agreement, and this Agreement, assuming due authorization, execution and
delivery by the Originator and the Purchaser, constitutes a legal, valid and
binding obligation of the Seller, enforceable against it in accordance with its
terms except as the enforceability thereof may be limited by bankruptcy,
insolvency or reorganization or by general principles of equity.

                  (iii) The execution, delivery and performance of this
Agreement by the Seller (x) does not conflict and will not conflict with, does
not breach and will not result in a breach of and does not constitute and will
not constitute a default (or an event, which with notice or lapse of time or
both, would constitute a default) under (A) any terms or provisions of the
articles of incorporation or by-laws of the Seller, (B) any term or provision of
any material agreement, contract, instrument or indenture, to which the Seller
is a party or by which the Seller or any of its property is bound or (C) any
law, rule, regulation, order, judgment, writ, injunction or decree of any court
or governmental authority having jurisdiction over the Seller or any of its
property and (y) does not create or impose and will not result in the creation
or imposition of any lien, charge or encumbrance which would have a material
adverse effect upon the Mortgage Loans or any documents or instruments
evidencing or securing the Mortgage Loans.

                                       -5-

<PAGE>

                  (iv) No consent, approval, authorization or order of,
registration or filing with, or notice on behalf of the Seller to any
governmental authority or court is required, under federal laws or the laws of
the State of Delaware, for the execution, delivery and performance by the Seller
of, or compliance by the Seller with, this Agreement or the consummation by the
Seller of any other transaction contemplated hereby and by the Pooling and
Servicing Agreement; provided, however, that the Seller makes no representation
or warranty regarding federal or state securities laws in connection with the
sale or distribution of the Certificates.

                  (v) This Agreement does not contain any untrue statement of
material fact or omit to state a material fact necessary to make the statements
contained herein not misleading. The written statements, reports and other
documents prepared and furnished or to be prepared and furnished by the Seller
pursuant to this Agreement or in connection with the transactions contemplated
hereby taken in the aggregate do not contain any untrue statement of material
fact or omit to state a material fact necessary to make the statements contained
therein not misleading.

                  (vi) The Seller is not in violation of, and the execution and
delivery of this Agreement by the Seller and its performance and compliance with
the terms of this Agreement will not constitute a violation with respect to, any
order or decree of any court or any order or regulation of any federal, state,
municipal or governmental agency having jurisdiction over the Seller or its
assets, which violation might have consequences that would materially and
adversely affect the condition (financial or otherwise) or the operation of the
Seller or its assets or might have consequences that would materially and
adversely affect the performance of its obligations and duties hereunder.

                  (vii) The Seller does not believe, nor does it have any reason
or cause to believe, that it cannot perform each and every covenant contained in
this Agreement.

                  (viii) Immediately prior to the sale of the Mortgage Loans to
the Purchaser as herein contemplated, the Seller will be the owner of the
related Mortgage and the indebtedness evidenced by the related Mortgage Note,
and, upon the payment to the Seller of the Purchase Price, the Purchaser shall
have good and marketable title to each Mortgage Loan, each related Mortgage Note
and the related Mortgage Files with respect thereto free and clear of all liens,
pledges, charges, claims security interests, participations and other
encumbrances.

                  (ix) There are no actions or proceedings against, or
investigations known to it of, the Seller before any court, administrative or
other tribunal (A) that might prohibit its entering into this Agreement, (B)
seeking to prevent the sale of the Mortgage Loans by the Seller or the
consummation of the transactions contemplated by this Agreement or (C) that
might prohibit or materially and adversely affect the performance by the Seller
of its obligations under, or validity or enforceability of, this Agreement.

                  (x) The consummation of the transactions contemplated by this
Agreement are in the ordinary course of business of the Seller, and the
transfer, assignment and conveyance of the Mortgage Notes and the Mortgages by
the Seller are not subject to the bulk transfer or any similar statutory
provisions.

                                       -6-

<PAGE>

                  (xi) The Seller has not dealt with any broker, investment
banker, agent or other person, except for the Purchaser or any of its
affiliates, that may be entitled to any commission or compensation in connection
with the sale of the Mortgage Loans (except that an entity that previously
financed the Seller's ownership of the Mortgage Loans may be entitled to a fee
to release its security interest in the Mortgage Loans, which fee shall have
been paid and which security interest shall have been released on or prior to
the Closing Date).

                  (xii) There is no litigation currently pending or, to the best
of the Seller's knowledge without independent investigation, threatened against
the Seller that would reasonably be expected to adversely affect the transfer of
the Mortgage Loans, the issuance of the Certificates or the execution, delivery,
performance or enforceability of this Agreement, or that would result in a
material adverse change in the financial condition of the Seller.

                  (xiii) As of the Closing Date, the Seller has no knowledge of
any circumstances or condition with respect to the Mortgaged Property, the
Mortgagor, the Mortgagor's credit standing or the Mortgage that can reasonably
be expected to cause the Mortgage Loan to be an unacceptable investment, cause
the Mortgage Loan to become delinquent, or adversely affect the value of the
Mortgage Loan.

                  (xiv) As of the Closing Date, the Mortgaged Property is
lawfully occupied under applicable law; 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, have been made or
obtained from the appropriate authorities.

                  (xv) As of the Closing Date, the Mortgaged Property is in
compliance with all applicable environmental laws pertaining to environmental
hazards including, without limitation, asbestos, and neither the Originator nor
any related seller of the Mortgage Loan nor, to the Originator's knowledge and
the knowledge of any related seller of the Mortgage Loan, the related Mortgagor,
has received any notice of any violation or potential violation of such law.

                  (xvi) As of the Closing Date, there are no delinquent taxes,
ground rents, water charges, sewer rents, assessments, insurance premiums,
leasehold payments, including assessments payable in future installments or
other outstanding charges affecting the related Mortgaged Property

                  (b) The Originator hereby represents and warrants to the
Seller and the Purchaser, as of the date hereof and as of the Closing Date, and
covenants, that:

                  (i) The Originator is duly organized, validly existing and in
good standing as a corporation under the laws of the State of California with
full corporate power and authority to conduct its business as presently
conducted by it to the extent material to the consummation of the transactions
contemplated herein. The Originator has the full corporate power and authority
to execute and deliver, engage in the transactions contemplated by, and perform
and observe the terms and conditions of this Agreement.

                                       -7-

<PAGE>

                  (ii) The Originator has duly authorized the execution,
delivery and performance of this Agreement, has duly executed and delivered this
Agreement, and this Agreement, assuming due authorization, execution and
delivery by the Seller and the Purchaser, constitutes a legal, valid and binding
obligation of the Originator, enforceable against it in accordance with its
terms except as enforceability thereof may be limited by bankruptcy, insolvency
or reorganization or by general principles of equity.

                  (iii) The execution, delivery and performance of this
Agreement by the Originator (x) does not conflict and will not conflict with,
does not breach and will not result in a breach of and does not constitute and
will not constitute a default (or an event, which with notice or lapse of time
or both, would constitute a default) under (A) any terms or provisions of the
articles of incorporation or by-laws of the Originator, (B) any term or
provision of any material agreement, contract, instrument or indenture, to which
the Originator is a party or by which the Originator or any of its property is
bound or (C) any law, rule, regulation, order, judgment, writ, injunction or
decree of any court or governmental authority having jurisdiction over the
Originator or any of its property and (y) does not create or impose and will not
result in the creation or imposition of any lien, charge or encumbrance which
would have a material adverse effect upon the Mortgage Loans or any documents or
instruments evidencing or securing the Mortgage Loans.

                  (iv) No consent, approval, authorization or order of,
registration or filing with, or notice on behalf of the Originator to any
governmental authority or court is required, under federal laws or the laws of
the State of California, for the execution, delivery and performance by the
Originator of, or compliance by the Originator with, this Agreement or the
consummation by the Originator of any other transaction contemplated hereby and
by the Pooling and Servicing Agreement; provided, however, that the Originator
makes no representation or warranty regarding federal or state securities laws
in connection with the sale or distribution of the Certificates.

                  (v) In this Agreement, the Originator has not made any untrue
statement of material fact or omit to state a material fact necessary to make
the statements contained herein not misleading. The written statements, reports
and other documents prepared and furnished or to be prepared and furnished by
the Originator pursuant to this Agreement or in connection with the transactions
contemplated hereby taken in the aggregate do not contain any untrue statement
of material fact or omit to state a material fact necessary to make the
statements contained therein not misleading.

                  (vi) The Originator is not in violation of, and the execution
and delivery of this Agreement by the Originator and its performance and
compliance with the terms of this Agreement will not constitute a violation with
respect to, any order or decree of any court or any order or regulation of any
federal, state, municipal or governmental agency having jurisdiction over the
Originator or its assets, which violation might have consequences that would
materially and adversely affect the condition (financial or otherwise) or the
operation of the Originator or its assets or might have consequences that would
materially and adversely affect the performance of its obligations and duties
hereunder.

                  (vii) The Originator does not believe, nor does it have any
reason or cause to believe, that it cannot perform each and every covenant
contained in this Agreement.

                                       -8-

<PAGE>

                  (viii) There are no actions or proceedings against, or
investigations known to it of, the Originator before any court, administrative
or other tribunal (A) that might prohibit its entering into this Agreement, (B)
seeking to void the sale of the Mortgage Loans by the Originator or any related
seller or the consummation of the transactions contemplated by this Agreement or
(C) that might prohibit or materially and adversely affect the performance by
the Originator of its obligations under, or validity or enforceability of, this
Agreement.

                  (ix)     [Reserved].

                  (x) There is no litigation currently pending or, to the best
of the Originator's knowledge without independent investigation, threatened
against the Originator or any related seller that would reasonably be expected
to adversely affect the transfer of the Mortgage Loans, the issuance of the
Certificates or the execution, delivery, performance or enforceability of this
Agreement, or that would result in a material adverse change in the financial
condition of the Originator.

                  SECTION 6.        REPRESENTATIONS AND WARRANTIES OF THE
                                    ORIGINATOR RELATING TO THE MORTGAGE LOANS.

                  The Originator hereby represents and warrants to the Purchaser
that as to each Mortgage Loan as of the Closing Date:

                  (i) The information set forth in the Mortgage Loan Schedule is
         complete, true and correct;

                  (ii)     [Reserved];

                  (iii) Except with respect to [__]% of the Group I Mortgage
Loans by outstanding principal balance of such group, all payments required to
be made up to the close of business on December 31, 2002 for such Mortgage Loan
under the terms of the Mortgage Note have been made and except with respect to
[__]% of the Group I Mortgage Loans by outstanding principal balance of such
group, all payments required to be made up to the close of business on January
31, 2003 for such Mortgage Loan under the terms of the Mortgage Note have been
made; the Originator has not advanced funds, or induced, solicited or knowingly
received any advance of funds from a party other than the owner of the related
Mortgaged Property, directly or indirectly, for the payment of any amount
required by the Note or Mortgage; and there has been no delinquency, exclusive
of any period of grace, in any payment by the Mortgagor thereunder during the
last twelve months;

                  (iv) At the time of its sale of the Mortgage Loan, there were
no delinquent taxes, ground rents, water charges, sewer rents, assessments,
insurance premiums, leasehold payments, including assessments payable in future
installments or other outstanding charges affecting the related Mortgaged
Property;

                  (v) The terms of the Mortgage Note and the Mortgage have not
been impaired, waived, altered or modified in any respect, except by written
instruments, recorded in the applicable

                                       -9-

<PAGE>

public recording office if necessary to maintain the lien priority of the
Mortgage, and which have been delivered to the Purchaser; the substance of any
such waiver, alteration or modification has been approved by the title insurer,
to the extent required by the related policy, and is reflected on the Mortgage
Loan Schedule. No instrument of waiver, alteration or modification has been
executed, and no Mortgagor has been released, in whole or in part, except in
connection with an assumption agreement approved by the title insurer, to the
extent required by the policy, and which assumption agreement has been delivered
to the Purchaser and the terms of which are reflected in the Mortgage Loan
Schedule;

                  (vi) The Mortgage Note and the Mortgage are not 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 and the
Mortgage or the exercise of any right thereunder, render the Mortgage
unenforceable, in whole or in part, or subject 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. Except with respect to [__]% of the Group I Mortgage Loans and
[__]% of the Group II Mortgage Loans by outstanding principal balance of each
such group, no Mortgagor was a debtor in any state or federal bankruptcy or
insolvency proceeding at the time the Mortgage Loan was originated or as of the
Closing Date;

                  (vii) All buildings upon the Mortgaged Property are insured by
an insurer acceptable to Fannie Mae against loss by fire, hazards of extended
coverage and such other hazards as are customary in the area where the Mortgaged
Property is located, pursuant to insurance policies conforming to the
requirements of the Pooling and Servicing Agreement. All such insurance policies
contain a standard mortgagee clause naming the Originator, its successors and
assigns as mortgagee and all premiums thereon have been paid. If the Mortgaged
Property is in an area identified on a Flood Hazard Map or Flood Insurance Rate
Map issued by the Federal Emergency Management Agency as having special flood
hazards (and such flood insurance has been made available) a flood insurance
policy meeting the requirements of the current guidelines of the Federal
Insurance Administration is in effect which policy conforms to the requirements
of Fannie Mae and Freddie Mac and is insured by a qualified insurer. The
Mortgage obligates the Mortgagor thereunder to maintain all such insurance at
the Mortgagor's cost and expense, and on the Mortgagor's failure to do so,
authorizes the holder of the Mortgage to maintain such insurance at the
Mortgagor's cost and expense and to seek reimbursement therefor from the
Mortgagor. No prior holder of the related Mortgage, including any related seller
of the Mortgage Loan, has done, by act or omission, anything which would impair
the coverage of such insurance policies;

                  (viii) Any and all requirements of any federal, state or local
law including, without limitation, usury, truth in lending, real estate
settlement procedures, consumer credit protection; equal credit opportunity,
fair housing or disclosure laws applicable to the origination and servicing of
loans of a type similar to the Mortgage Loans have been complied with and the
Originator shall maintain in its possession available for inspection, and shall
deliver to the Purchaser, upon reasonable request, evidence of compliance with
all such requirements;

                  (ix) The Mortgage has not been satisfied, cancelled,
subordinated or rescinded, in whole or in part, and the Mortgaged Property has
not been released from the lien of the Mortgage,

                                      -10-

<PAGE>

in whole or in part, nor has any instrument been executed that would effect any
such satisfaction, cancellation, subordination, rescission or release;

                  (x) The Mortgage is a valid, existing, enforceable and
perfected first or second lien on the Mortgaged Property, including all
improvements on the Mortgaged Property 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 the
public record as of the date of recording being acceptable to mortgage lending
institutions generally and specifically referred to in the lender's title
insurance policy delivered to the Originator and which do not adversely affect
the Value of the Mortgaged Property, (c) other matters to which like properties
are commonly subject which do not materially interfere with the benefits of the
security intended to be provided by the Mortgage or the use, enjoyment, value or
marketability of the related Mortgaged Property and (d) in the case of any
second lien Mortgage Loan, the first lien on the related Mortgaged Property. Any
security agreement, chattel mortgage or equivalent document related to and
delivered in connection with the Mortgage Loan establishes and creates a valid,
existing and enforceable first or second lien and first or second priority
security interest on the property described therein and the Originator and any
related seller of the Mortgage Loan had full right to sell and assign the same
to the Seller. The Mortgaged Property was not, as of the date of origination of
the Mortgage Loan, subject to a mortgage, deed of trust, deed to secure debt or
other security instrument creating a lien subordinate to the lien of the
Mortgage;

                  (xi) The Mortgage Note and the related Mortgage are genuine
and each is the legal, valid and binding obligation of the maker thereof,
enforceable in accordance with its terms;

                  (xii) All parties to the Note and the Mortgage had legal
capacity to enter into the Mortgage Loan and to execute and deliver the Mortgage
Note and the Mortgage, and the Mortgage Note and the Mortgage have been duly and
properly executed by such parties. The Mortgagor is a natural person;

                  (xiii) The proceeds of the Mortgage Loan have been fully
disbursed to or for the account of the Mortgagor and there is no obligation for
the Mortgagee to advance additional funds thereunder and any and all
requirements as to completion of any on-site or off-site improvement and as to
disbursements of any escrow funds therefor have been complied with. All costs,
fees and expenses incurred in making or closing the Loan and the recording of
the Mortgage have been paid, and the Mortgagor is not entitled to any refund of
any amounts paid or due to the Mortgagee pursuant to the Mortgage Note or
Mortgage;

                  (xiv) At the time of its sale of the Mortgage Loan, the
Originator was the sole legal, beneficial and equitable owner of the Mortgage
Note and the Mortgage and had full right to transfer and sell the Mortgage Loan
free and clear of any encumbrance, equity, lien, pledge, charge, claim or
security interest;

                  (xv) All parties which had any interest in the Mortgage Loan,
whether as mortgagee, assignee or otherwise, are (or, during the period in which
they held and disposed of such interest, were) in compliance with any and all
applicable "doing business" and licensing requirements of the laws of the state
wherein the Mortgaged Property is located;

                                      -11-

<PAGE>

                  (xvi) The Mortgage Loan is covered by an ALTA lender's title
insurance policy (which, in the case of an Adjustable-Rate Mortgage Loan has an
adjustable rate mortgage endorsement in the form of ALTA 6.0 or 6.1) or with
respect to any Mortgage Loan for which the related Mortgaged Property is located
in California a CLTA lender's title insurance policy, or other generally
acceptable form of policy or insurance acceptable to Fannie Mae and Freddie Mac,
issued by a title insurer acceptable to Fannie Mae and Freddie Mac and qualified
to do business in the jurisdiction where the Mortgaged Property is located,
insuring (subject to the exceptions contained in (x)(a) and (b) above) the
Originator, its successors and assigns as to the first or second priority lien
of the Mortgage in the original principal amount of the Mortgage Loan and, with
respect to any Adjustable-Rate Mortgage Loan, against any loss by reason of the
invalidity or unenforceability of the lien resulting from the provisions of the
Mortgage providing for adjustment in the Mortgage Rate and Monthly Payment.
Additionally, such lender's title insurance policy affirmatively insures ingress
and egress to and from the Mortgaged Property, and against encroachments by or
upon the Mortgaged Property or any interest therein. The Originator is the sole
insured of such lender's title insurance policy, and such lender's title
insurance policy is in full force and effect and will be in full force and
effect upon the consummation of the transactions contemplated by this Agreement.
No claims have been made under such lender's title insurance policy, and no
prior holder of the related Mortgage including the Originator, has done, by act
or omission, anything which would impair the coverage of such lender's title
insurance policy;

                  (xvii) There is no default, breach, violation or event of
acceleration existing under the Mortgage Note or the Mortgage 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, and neither the Originator nor any related seller of the Mortgage
Loan, has waived any default, breach, violation or event of acceleration;

                  (xviii) There are no mechanics' or similar liens or claims
which have been filed for work, labor or material (and no rights are outstanding
that under law could give rise to such lien) affecting the related Mortgaged
Property which are or may be liens prior to, or equal or coordinate with, the
lien of the related Mortgage;

                  (xix) All improvements which were considered in determining
the Value of the related Mortgaged Property lay wholly within the boundaries and
building restriction lines of the Mortgaged Property, and no improvements on
adjoining properties encroach upon the Mortgaged Property unless otherwise
disclosed and are affirmatively insured by the title insurance policy referred
to in (xvi) above;

                  (xx) The Mortgage Loan was originated by the Originator or by
a savings and loan association, a savings bank, a commercial bank or similar
banking institution which is supervised and examined by a federal or state
authority, or by a mortgagee approved as such by the Secretary of HUD;

                  (xxi) Principal payments on the Mortgage Loan shall commence
(with respect to any newly originated Mortgage Loans) or commenced no more than
two months after the proceeds of the Mortgage Loan were disbursed. The Mortgage
Loan bears interest at the Mortgage Rate. With respect to each Mortgage Loan,
the Mortgage Note is payable on the related Due Date in

                                      -12-

<PAGE>

Monthly Payments, which, (A) in the case of a Fixed-Rate Mortgage Loan, are
sufficient to fully amortize the original principal balance over the original
term thereof and to pay interest at the related Mortgage Rate, (B) in the case
of an Adjustable-Rate Mortgage Loan, are changed on each Adjustment Date, and in
any case, are sufficient to fully amortize the original principal balance over
the original term thereof and to pay interest at the related Mortgage Rate and
(C) in the case of a Balloon Loan, are based on a fifteen (15) or thirty (30)
year amortization schedule, as applicable, as set forth in the related Mortgage
Note and Mortgage Loan Schedule, and a final monthly payment substantially
greater than the preceding monthly payment which is sufficient to amortize the
remaining principal balance of the Balloon Loan and to pay interest at the
related Mortgage Rate. The Mortgage Note does not permit negative amortization;

                  (xxii) The Mortgaged Property is free of material damage and
waste and there is no proceeding pending, or to the best of the Originator's or
any related seller's knowledge threatened, for the total or partial condemnation
thereof;

                  (xxiii) The Mortgage and related Mortgage Note contain
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 provided thereby, including, (a) in the
case of a Mortgage designated as a deed of trust, by trustee's sale, and (b)
otherwise by judicial foreclosure. Upon default by a Mortgagor on a Mortgage
Loan and foreclosure on, or trustee's sale of, the Mortgaged Property pursuant
to the proper procedures, the holder of the Mortgage Loan will be able to
deliver good and merchantable title to the Mortgaged Property. The Mortgaged
Property has not been subject to any bankruptcy proceeding or foreclosure
proceeding and the Mortgagor has not filed for protection under applicable
bankruptcy laws. There is no homestead or other exemption available to the
Mortgagor which would interfere with the right to sell the Mortgaged Property at
a trustee's sale or the right to foreclose the Mortgage. The Mortgagor has not
notified the Originator or any related seller of the Mortgage Loans and neither
the Originator nor any related seller of the Mortgage Loans has any knowledge of
any relief requested or allowed to the Mortgagor under the Soldiers and Sailors
Civil Relief Act of 1940;

                  (xxiv) The Mortgage Loan was underwritten in accordance with
the underwriting standards of the Originator in effect at the time the Mortgage
Loan was originated. The Mortgage Note, the Mortgage and all other documents
contained in the Mortgage File are on Fannie Mae or Freddie Mac uniform
instruments or are on forms acceptable to Fannie Mae or Freddie Mac or to
prudent mortgage lenders that regularly originate or purchase mortgage loans
comparable to the Mortgage Loans for sale to prudent investors in the secondary
market that invest in mortgage loans such as the Mortgage Loans;

                  (xxv) The Mortgage Note is not and has not been secured by any
collateral except the lien of the corresponding Mortgage and the security
interest of any applicable security agreement or chattel mortgage referred to in
(x) or (xi) above;

                  (xxvi) The Mortgage File contains an appraisal of the related
Mortgaged Property signed prior to the approval of the Mortgage Loan application
by a qualified appraiser, duly appointed by the Originator who had no interest,
direct or indirect in the Mortgaged Property or in any loan made on the security
thereof, and whose compensation is not affected by the approval or

                                      -13-

<PAGE>

disapproval of the Mortgage Loan, and the appraisal and appraiser both satisfy
the requirements of Fannie Mae or Freddie Mac and Title XI of the Financial
Institutions Reform, Recovery, and Enforcement Act of 1989 and the regulations
promulgated thereunder, all as in effect on the date the Mortgage Loan was
originated;

                  (xxvii) In the event the Mortgage constitutes a deed of trust,
a trustee, duly qualified under applicable law to serve as such, has been
properly designated and currently so serves and is named in the Mortgage, and no
fees or expenses are or will become payable by the Purchaser to the trustee
under the deed of trust, except in connection with a trustee's sale after
default by the Mortgagor;

                  (xxviii) No Mortgage Loan contains provisions pursuant to
which Monthly Payments are (a) paid or partially paid with funds deposited in
any separate account established by the Originator, the Mortgagor, or anyone on
behalf of the Mortgagor, (b) paid by any source other than the Mortgagor or (c)
except with respect to buydown Mortgage Loans, contains any other similar
provisions which may constitute a buydown provision. The Mortgage Loan is not a
graduated payment loan and the Mortgage Loan does not have a shared appreciation
or other contingent interest feature;

                  (xxix) The Mortgagor has executed a statement to the effect
that the Mortgagor has received all disclosure materials required by applicable
law with respect to the making of fixed rate mortgage loans in the case of
Fixed-Rate Mortgage Loans, and adjustable rate mortgage loans in the case of
Adjustable-Rate Mortgage Loans and rescission materials with respect to
Refinanced Mortgage Loans, and such statement is and will remain in the Mortgage
File;

                  (xxx) No Mortgage Loan was made in connection with (a) the
construction or rehabilitation of a Mortgaged Property or (b) facilitating the
trade-in or exchange of a Mortgaged Property;

                  (xxxi) At the time of its sale of the Mortgage Loan, neither
the Originator nor any related seller of the Mortgage Loans has any knowledge of
any circumstances or condition with respect to the Mortgaged Property, the
Mortgagor, the Mortgagor's credit standing or the Mortgage that can reasonably
be expected to cause the Mortgage Loan to be an unacceptable investment, cause
the Mortgage Loan to become delinquent, or adversely affect the value of the
Mortgage Loan;

                  (xxxii) No Mortgage Loan had a Loan-to-Value Ratio at
origination in excess of 100%;

                  (xxxiii) At the time of its sale of the Mortgage Loans, the
Mortgaged Property was lawfully occupied under applicable law; 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,
have been made or obtained from the appropriate authorities;

                  (xxxiv) No error, omission, misrepresentation, negligence,
fraud or similar occurrence with respect to a Mortgage Loan has taken place on
the part of the Originator or any

                                      -14-

<PAGE>

related seller of the Mortgage Loan, or to the best of the Originator's
knowledge, the Mortgagor, the appraiser, any builder, or any developer, or any
other party involved in the origination of the Mortgage Loan or in the
application of any insurance in relation to such Mortgage Loan;

                  (xxxv) Except for the blank for the name of the assignee, the
Assignment of Mortgage is in recordable form and is acceptable for recording
under the laws of the jurisdiction in which the Mortgaged Property is located;

                  (xxxvi) Any principal advances made to the Mortgagor prior to
the Cut-off Date have been consolidated with the outstanding principal amount
secured by the Mortgage, and the secured principal amount, as consolidated,
bears a single interest rate and single repayment term. The lien of the Mortgage
securing the consolidated principal amount is expressly insured as having first
or second lien priority by a title insurance policy, an endorsement to the
policy insuring the mortgagee's consolidated interest or by other title evidence
acceptable to Fannie Mae and Freddie Mac. The consolidated principal amount does
not exceed the original principal amount of the Mortgage Loan;

                  (xxxvii) Except with respect to each Mortgage Loan identified
as a Balloon Loan on the Mortgage Loan Schedule, no Mortgage Loan has a balloon
payment feature;

                  (xxxviii) If the Residential Dwelling on the Mortgaged
Property is a condominium unit or unit in a planned unit development (other than
a DE MINIMIS planned unit development) such condominium or planned unit
development project meets the eligibility requirements of Fannie Mae;

                  (xxxix) Each Mortgage Loan constitutes a qualified mortgage
under Section 860(a)(3)(A) of the Code and Treasury Regulations Section
1.860G-2(a)(1);

                  (xl) None of the Mortgage Loans are classified as (a) "high
cost" loans under the Home Ownership and Equity Protection Act of 1994, or (b)
"high cost," "threshold," or "predatory" loans under any other applicable state,
federal or local law;

                  (xli) None of the proceeds of the Mortgage Loan were used to
finance single- premium credit life or disability insurance policies or any
comparable insurance;

                  (xlii) Interest on each Mortgage Loan is calculated on the
basis of a 360-day year consisting of twelve 30-day months;

                  (xliii) At the time of its sale of the Mortgage Loan, the
Mortgaged Property was in compliance with all applicable environmental laws
pertaining to environmental hazards including, without limitation, asbestos, and
neither the Originator nor any related seller of the Mortgage Loan nor, to the
Originator's knowledge and the knowledge of any related seller of the Mortgage
Loan, the related Mortgagor, has received any notice of any violation or
potential violation of such law;

                  (xliv) None of the Mortgage Loans are buydown Mortgage Loans;

                                      -15-

<PAGE>

                  (xlv) Any Mortgaged Property that is considered manufactured
housing is legally classified as real property, is permanently affixed to a
foundation and assumes the characteristics of site-built housing and otherwise
conforms to the requirements of Fannie Mae and Freddie Mac;

                  (xlvi) With respect to each Mortgage Loan secured in whole or
in part by the interest of the Mortgagor as a lessee under a ground lease of a
Mortgaged Property (a "Ground Lease") the real property securing such Mortgage
Loan is located in a jurisdiction in which the use of leasehold estates for
residential properties is a widely-accepted practice and (a) such Ground Lease
is valid, in good standing, and in full force and effect; (b) the lessee is not
in default under any provision of the lease; (c) the term of the Ground Lease
exceeds the maturity date of the related Mortgage Loan by at least ten years;
(d) the mortgagee under the Mortgage Loan is given at least 30 days' notice of
any default and an opportunity to cure any defaults under the Ground Lease or to
take over the Mortgagor's rights under the Ground Lease; (e) the Ground Lease
does not contain any default provisions that could give rise to forfeiture or
termination of the Ground Lease except for the non- payment of the Ground lease
rents; and (f) the Ground Lease provides that the leasehold can be transferred,
mortgaged and sublet an unlimited number of times either without restriction or
on payment of a reasonable fee and delivery of reasonable documentation to the
lessor;

                  (xlvii) The Mortgage contains an enforceable provision for the
acceleration of the payment of the unpaid principal balance of the Loan in the
event that the Mortgaged Property is sold or transferred without the prior
written consent of the mortgagee thereunder;

                  (xlviii) The Mortgage Loan complies with all applicable
consumer credit statutes and regulations, including, without limitation, the
respective Uniform Consumer Credit Code laws in effect in Colorado, Idaho,
Indiana, Iowa, Kansas, Maine, Oklahoma, South Carolina, Utah and Wyoming, has
been originated by a properly licensed entity, and in all other respects,
complies with all of the material requirements of any such applicable laws;

                  (xlix) For any Mortgage Loan originated prior to October 1,
2002 that is subject to a Prepayment Charge, such Prepayment Charge does not
extend beyond five years after the date of origination. For any Mortgage Loan
originated on or following October 1, 2002 that is subject to a Prepayment
Charge, such Prepayment Charge does not extend beyond three years after the date
of origination;

                  (l) No Group I Mortgage Loan secured by a Mortgaged Property
located in Georgia was originated on or after October 1, 2002.

                  (li) None of the Group II Mortgage Loans are subject to the
Georgia Fair Lending Act (the "GEORGIA ACT").

                  (lii) The Originator has complied with all applicable
anti-money laundering laws and regulations, including without limitation the USA
Patriot Act of 2001 (collectively, the "Anti- Money Laundering Laws"); the
Originator has established an anti-money laundering compliance program as
required by the Anti-Money Laundering Laws, has conducted the requisite due
diligence in connection with the origination of each Loan for purposes of the
Anti-Money Laundering Laws, including with respect to the legitimacy of the
applicable Mortgagor and the origin of the assets used

                                      -16-

<PAGE>

by the said Mortgagor to purchase the property in question, and maintains, and
will maintain, sufficient information to identify the applicable Mortgagor for
purposes of the Anti-Money Laundering Laws.

                  SECTION 7.        REPURCHASE OBLIGATION FOR DEFECTIVE
                                    DOCUMENTATION AND FOR BREACH OF
                                    REPRESENTATION AND WARRANTY.

                  (a) The representations and warranties contained in Section 6
shall not be impaired by any review and examination of loan files or other
documents evidencing or relating to the Mortgage Loans or any failure on the
part of the Seller or the Purchaser to review or examine such documents and
shall inure to the benefit of any assignee, transferee or designee of the
Purchaser, including the Trustee for the benefit of holders of the Certificates.
Other than with respect to the representation and warranty contained in Section
6(xxxiv), with respect to the representations and warranties contained herein as
to which the Originator has no knowledge, if it is discovered that the substance
of any such representation and warranty was inaccurate as of the date such
representation and warranty was made or deemed to be made, and such inaccuracy
materially and adversely affects the value of the related Mortgage Loan or the
interest therein of the Purchaser or the Purchaser's assignee, transferee or
designee, then notwithstanding the lack of knowledge by the Originator with
respect to the substance of such representation and warranty being inaccurate at
the time the representation and warranty was made, the Originator shall take
such action described in the following paragraph in respect of such Mortgage
Loan.

                  Upon discovery by the Seller, the Purchaser or any assignee,
transferee or designee of the Purchaser of any materially defective document in,
or that any material document was not transferred by the Seller (as listed on
the Trustee's Initial Certification) as part of any Mortgage File, or of a
breach of any of the representations and warranties contained in Section 6 that
materially and adversely affects the value of any Mortgage Loan or the interest
therein of the Purchaser or the Purchaser's assignee, transferee or designee,
the party discovering such breach shall give prompt written notice to the
Originator and the Seller; provided, that a breach of the representations and
warranties made in Section 6(xl), (xli), (xlix), (l) and (li) shall be deemed to
materially and adversely affects the value of any Mortgage Loan or the interest
therein of the Certificateholders. Within sixty (60) days of its discovery or
its receipt of notice of any such missing documentation that was not transferred
by the Seller as described above, or of materially defective documentation, or
of any such breach of a representation and warranty, the Originator or the
Seller, as applicable, promptly shall deliver such missing document or cure such
defect or breach in all material respects or, in the event the Originator or the
Seller, as applicable, cannot deliver such missing document or cannot cure such
defect or breach, the Originator or the Seller, as applicable, shall, within
ninety (90) days of its discovery or receipt of notice, either (i) repurchase
the affected Mortgage Loan at the Purchase Price or (ii) pursuant to the
provisions of the Pooling and Servicing Agreement, cause the removal of such
Mortgage Loan from the Trust Fund and substitute one or more Qualified
Substitute Mortgage Loans. The Originator or the Seller, as applicable, shall
amend the Closing Schedule to reflect the withdrawal of such Mortgage Loan from
the terms of this Agreement and the Pooling and Servicing Agreement. The
Originator or the Seller, as applicable, shall deliver to the Purchaser such
amended Closing Schedule and shall deliver such other documents as are required
by this Agreement or the Pooling and Servicing Agreement within five (5) days of
any such amendment. Any repurchase pursuant to this Section 7(a) shall be
accomplished by transfer to an account designated by the

                                      -17-

<PAGE>

Purchaser of the amount of the Purchase Price in accordance with Section 2.03 of
the Pooling and Servicing Agreement. Any repurchase required by this Section
shall be made in a manner consistent with Section 2.03 of the Pooling and
Servicing Agreement.

                  Notwithstanding the foregoing, to the extent a representation
or warranty of the Seller regarding the Mortgage Loans has been breached and the
circumstance constituting the breach also constitutes a breach of a like
representation or warranty given by the Originator as of an earlier date, the
Purchaser's remedy hereunder shall be solely against the Originator and not the
Seller.

                  (b) It is understood and agreed that the obligations of the
Originator or the Seller, as applicable, set forth in this Section 7 to cure or
repurchase a defective Mortgage Loan constitute the sole remedies of the
Purchaser against the Originator or the Seller, as applicable, respecting a
missing document or a breach of the representations and warranties contained in
Section 6.

                  SECTION 8. CLOSING; PAYMENT FOR THE MORTGAGE LOANS. The
closing of the purchase and sale of the Mortgage Loans shall be held at the New
York City office of Thacher Proffitt & Wood at 10:00 a.m. New York City time on
the Closing Date.

                  The closing shall be subject to each of the following
conditions:

                  (a) All of the representations and warranties of the Seller
         under this Agreement shall be true and correct in all material respects
         as of the date as of which they are made and no event shall have
         occurred which, with notice or the passage of time, would constitute a
         default under this Agreement;

                  (b) All of the representations and warranties of the
         Originator under this Agreement shall be true and correct in all
         material respects as of the date as of which they are made and no event
         shall have occurred which, with notice or the passage of time, would
         constitute a default under this Agreement;

                  (c) The Purchaser shall have received, or the attorneys of the
         Purchaser shall have received in escrow (to be released from escrow at
         the time of closing), all Closing Documents as specified in Section 9
         of this Agreement, in such forms as are agreed upon and acceptable to
         the Purchaser, duly executed by all signatories other than the
         Purchaser as required pursuant to the respective terms thereof;

                  (d) The Seller shall have delivered or caused to be delivered
         and released to the Purchaser or to its designee, all documents
         (including without limitation, the Mortgage Loans) required to be so
         delivered by the Purchaser pursuant to Section 2.01 of the Pooling and
         Servicing Agreement; and

                  (e) All other terms and conditions of this Agreement and the
         Pooling and Servicing Agreement shall have been complied with.

                  Subject to the foregoing conditions, the Purchaser shall
deliver or cause to be delivered to the Seller on the Closing Date, against
delivery and release by the Seller to the Trustee

                                      -18-

<PAGE>

of all documents required pursuant to the Pooling and Servicing Agreement, the
Purchase Price for the Mortgage Loans as specified in Section 3 of this
Agreement.

                  SECTION 9. CLOSING DOCUMENTS. Without limiting the generality
of Section 8 hereof, the closing shall be subject to delivery of each of the
following documents:

                  (a) A Secretary's Certificate of the Seller, dated the Closing
         Date, in form satisfactory to and upon which the Originator, the
         Purchaser and UBS Warburg LLC (the "Underwriter") may rely, and
         attached thereto copies of the certificate of incorporation, by- laws
         and certificate of good standing of the Seller under the laws of
         Delaware;

                  (b) An Opinion of Counsel of the Seller, dated the Closing
         Date, in form satisfactory to and addressed to the Underwriter;

                  (c) An Officer's Certificate of the Originator, dated the
         Closing Date, in form satisfactory to and upon which the Seller, the
         Purchaser and the Underwriter may rely, and attached thereto copies of
         the certificate of incorporation, by-laws and certificate of good
         standing of the Originator under the laws of its state of
         incorporation;

                  (d) An opinion of Counsel of the Originator, dated the Closing
         Date, in form satisfactory to and addressed to the Underwriter;

                  (e) Such opinions of counsel as the Rating Agencies or the
         Trustee may request in connection with the sale of the Mortgage Loans
         by the Seller to the Purchaser or the Seller's execution and delivery
         of, or performance under, this Agreement;

                  (f) A letter from Deloitte & Touche LLP, certified public
         accountants, to the effect that they have performed certain specified
         procedures as a result of which they determined that certain
         information of an accounting, financial or statistical nature set forth
         in the Prospectus Supplement contained under the captions
         "Summary--Mortgage Loans," "Risk Factors," (to the extent of
         information concerning the Mortgage Loans contained therein) and
         "Description of the Mortgage Loans" agrees with the records of the
         Originator;

                  (g) Such further information, certificates, opinions and
         documents as the Purchaser or the Underwriter may reasonably request.

                  SECTION 10. COSTS. The Seller shall pay (or shall reimburse
the Purchaser or any other Person to the extent that the Purchaser or such other
Person shall pay) the fees and expenses of the Seller's accountants and
attorneys and the costs and expenses incurred in connection with obtaining the
documents referred to in Sections 9(a), 9(b), 9(e) and 9(f), the costs and
expenses of printing (or otherwise reproducing) and delivering this Agreement,
the Pooling and Servicing Agreement, the Certificates, the prospectus and
Prospectus Supplement, and any private placement memorandum relating to the
Certificates and other related documents, the initial fees, costs and expenses
of the Trustee, the fees and expenses of the Purchaser's counsel in connection
with the preparation of all documents relating to the securitization of the
Mortgage Loans, the filing fee charged by the Securities and Exchange Commission
for registration of the Certificates and the fees

                                      -19-

<PAGE>

charged by any rating agency to rate the Certificates. All other costs and
expenses in connection with the transactions contemplated hereunder shall be
borne by the party incurring such expense.

                  SECTION 11. [RESERVED].

                  SECTION 12. INDEMNIFICATION. The Originator shall indemnify
and hold harmless each of (i) the Purchaser, (ii) the Underwriter, (iii) the
Person, if any, to which the Purchaser assigns its rights in and to a Mortgage
Loan and each of their respective successors and assigns and (iv) each person,
if any, who controls the Purchaser within the meaning of Section 15 of the
Securities Act of 1933, as amended (the "1933 Act") ((i) through (iv)
collectively, the "Indemnified Party") against any and all losses, claims,
expenses, damages or liabilities to which the Indemnified Party may become
subject, under the 1933 Act or otherwise, insofar as such losses, claims,
expenses, damages or liabilities (or actions in respect thereof) arise out of or
are based upon (a) any untrue statement or alleged untrue statement of any
material fact contained in the Prospectus Supplement or any private placement
memorandum relating to the offering by the Purchaser or an affiliate thereof, of
the Class CE Certificates or the Class P Certificates, or the omission or the
alleged omission to state therein the material fact necessary in order to make
the statements therein not misleading, in each case to the extent, but only to
the extent, that such untrue statement or alleged untrue statement or omission
or alleged omission was made in reliance upon and in conformity with (i)
information furnished in writing to the Purchaser or any of its affiliates by
the Originator or any of its affiliates specifically for use therein, which
shall include, with respect to the Prospectus Supplement, the information set
forth under the captions "Summary--Mortgage Loans," "Risk Factors," (to the
extent of information concerning the Mortgage Loans contained therein),
"Description of the Mortgage Loans," "Underwriting Standards of Option One
Mortgage Corporation" and "The Master Servicer" and, with respect to any private
placement memorandum, any information of a comparable nature, or (ii) the data
files containing information with respect to the Mortgage Loans as transmitted
by modem to the Purchaser by the Originator or any of its affiliates (as such
transmitted information may have been amended in writing by the Originator or
any of its affiliates with the written consent of the Purchaser subsequent to
such transmission), (b) any representation, warranty or covenant made by the
Originator or any affiliate of the Originator herein or in the Pooling and
Servicing Agreement, on which the Purchaser has relied, being, or alleged to be,
untrue or incorrect or (c) any updated collateral information provided by the
Underwriter to a purchaser of the Certificates derived from the data contained
in clause (ii) and any current collateral tape obtained from the Originator or
an affiliate of the Originator, including the current loan balances of the
Mortgage Loans; provided, however, that to the extent that any such losses,
claims, expenses, damages or liabilities to which the Indemnified Party may
become subject arise out of or are based upon both (1) statements, omissions,
representations, warranties or covenants of the Originator described in clause
(a), (b) or (c) above and (2) any other factual basis, the Originator shall
indemnify and hold harmless the Indemnified Party only to the extent that the
losses, claims, expenses, damages, or liabilities of the person or persons
asserting the claim are determined to rise from or be based upon matters set
forth in clause (1) above and do not result from the gross negligence or willful
misconduct of such Indemnified Party. This indemnity shall be in addition to any
liability that the Originator may otherwise have.

                  SECTION 13. MANDATORY DELIVERY; GRANT OF SECURITY INTEREST.
The sale and delivery on the Closing Date of the Mortgage Loans described on the
Mortgage Loan Schedule in accordance with the terms and conditions of this
Agreement is mandatory. It is specifically understood and

                                      -20-

<PAGE>

agreed that each Mortgage Loan is unique and identifiable on the date hereof and
that an award of money damages would be insufficient to compensate the Purchaser
for the losses and damages incurred by the Purchaser in the event of the
Seller's failure to deliver the Mortgage Loans on or before the Closing Date.
The Seller hereby grants to the Purchaser a lien on and a continuing security
interest in the Seller's interest in each Mortgage Loan and each document and
instrument evidencing each such Mortgage Loan to secure the performance by the
Seller of its obligation hereunder, and the Seller agrees that it holds such
Mortgage Loans in custody for the Purchaser, subject to the Purchaser's (i)
right, prior to the Closing Date, to reject any Mortgage Loan to the extent
permitted by this Agreement, and (ii) obligation to deliver or cause to be
delivered the consideration for the Mortgage Loans pursuant to Section 8 hereof.
Any Mortgage Loans rejected by the Purchaser shall concurrently therewith be
released from the security interest created hereby. All rights and remedies of
the Purchaser under this Agreement are distinct from, and cumulative with, any
other rights or remedies under this Agreement or afforded by law or equity and
all such rights and remedies may be exercised concurrently, independently or
successively.

                  Notwithstanding the foregoing, if on the Closing Date, each of
the conditions set forth in Section 8 hereof shall have been satisfied and the
Purchaser shall not have paid or caused to be paid the Purchase Price, or any
such condition shall not have been waived or satisfied and the Purchaser
determines not to pay or cause to be paid the Purchase Price, the Purchaser
shall immediately effect the re-delivery of the Mortgage Loans, if delivery to
the Purchaser has occurred, and the security interest created by this Section 12
shall be deemed to have been released.

                  SECTION 14. NOTICES. All demands, notices and communications
hereunder shall be in writing and shall be deemed to have been duly given if
personally delivered to or mailed by registered mail, postage prepaid, or
transmitted by fax and, receipt of which is confirmed by telephone, if to the
Purchaser, addressed to the Purchaser at 1285 Avenue of the Americas, New York,
New York 10019, facsimile number (212) 713-7999, Attention: Glenn McIntyre, or
such other address as may hereafter be furnished to the Seller and the
Originator in writing by the Purchaser; if to the Seller, addressed to the
Seller at 1285 Avenue of the Americas, New York, New York 10019, facsimile
number (212) 713-7999, Attention: Glenn McIntyre, or to such other address as
the Seller may designate in writing to the Purchaser and the Originator; and if
to the Originator, addressed to Option One Mortgage Corporation at 3 Ada,
Irvine, California 92612, fax (949) 790- 7540, Attention: William O'Neill, or
such other address as may hereafter be furnished to the Seller and the Purchaser
in writing by the Originator.

                  SECTION 15. SEVERABILITY OF PROVISIONS. Any part, provision,
representation or warranty of this Agreement that is prohibited or that is held
to be void or unenforceable shall be ineffective to the extent of such
prohibition or unenforceability without invalidating the remaining provisions
hereof. Any part, provision, representation or warranty of this Agreement that
is prohibited or unenforceable or is held to be void or unenforceable in any
jurisdiction shall, as to such jurisdiction, be ineffective to the extent of
such prohibition or unenforceability without invalidating the remaining
provisions hereof, and any such prohibition or unenforceability in any
jurisdiction as to any Mortgage Loan shall not invalidate or render
unenforceable such provision in any other jurisdiction. To the extent permitted
by applicable law, the parties hereto waive any provision of law which prohibits
or renders void or unenforceable any provision hereof.

                                      -21-

<PAGE>

                  SECTION 16. AGREEMENT OF PARTIES. The Originator, the Seller
and the Purchaser each agree to execute and deliver such instruments and take
such actions as either of the others may, from time to time, reasonably request
in order to effectuate the purpose and to carry out the terms of this Agreement
and the Pooling and Servicing Agreement.

                  SECTION 17. SURVIVAL. (a) The Seller agrees that the
representations, warranties and agreements made by it herein and in any
certificate or other instrument delivered pursuant hereto shall be deemed to be
relied upon by the Purchaser, notwithstanding any investigation heretofore or
hereafter made by the Purchaser or on its behalf, and that the representations,
warranties and agreements made by the Seller herein or in any such certificate
or other instrument shall survive the delivery of and payment for the Mortgage
Loans and shall continue in full force and effect, notwithstanding any
restrictive or qualified endorsement on the Mortgage Notes and notwithstanding
subsequent termination of this Agreement, the Pooling and Servicing Agreement or
the Trust Fund. (b) the Originator agrees that the representations, warranties
and agreements made by it herein and in any certificate or other instrument
delivered pursuant hereto shall be deemed to be relied upon by the Seller and
the Purchaser notwithstanding any investigation heretofore or hereafter made by
the Seller or the Purchaser or on the behalf of either of them, and that the
representations, warranties and agreements made by the Originator herein or in
any such certificate shall continue in full force and effect, notwithstanding
subsequent termination of this Agreement, the Pooling and Servicing Agreement or
the Trust Fund.

                  SECTION 18. GOVERNING LAW. THIS AGREEMENT AND THE RIGHTS,
DUTIES, OBLIGATIONS AND RESPONSIBILITIES OF THE PARTIES HERETO SHALL BE GOVERNED
BY AND CONSTRUED IN ACCORDANCE WITH THE LAWS (OTHER THAN THE CHOICE OF LAW
PROVISIONS THEREIN) AND DECISIONS OF THE STATE OF NEW YORK. THE PARTIES HERETO
INTEND THAT THE PROVISIONS OF SECTION 5-1401 OF THE NEW YORK GENERAL OBLIGATIONS
LAW SHALL APPLY TO THIS AGREEMENT.

                  SECTION 19. MISCELLANEOUS. This Agreement may be executed in
two or more counterparts, each of which when so executed and delivered shall be
an original, but all of which together shall constitute one and the same
instrument. This Agreement shall inure to the benefit of and be binding upon the
parties hereto and their respective successors and assigns. This Agreement
supersedes all prior agreements and understandings relating to the subject
matter hereof. Neither this Agreement nor any term hereof may be changed,
waived, discharged or terminated orally, but only by an instrument in writing
signed by the party against whom enforcement of the change, waiver, discharge or
termination is sought. The headings in this Agreement are for purposes of
reference only and shall not limit or otherwise affect the meaning hereof.

                  It is the express intent of the parties hereto that the
conveyance of the Mortgage Loans by the Seller to the Purchaser as provided in
Section 4 hereof be, and be construed as, a sale of the Mortgage Loans by the
Seller to the Purchaser and not as a pledge of the Mortgage Loans by the Seller
to the Purchaser to secure a debt or other obligation of the Seller. However, in
the event that, notwithstanding the aforementioned intent of the parties, the
Mortgage Loans are held to be property of the Seller, then (a) it is the express
intent of the parties that such conveyance be deemed a pledge of the Mortgage
Loans by the Seller to the Purchaser to secure a debt or other obligation of the
Seller and (b) (1) this Agreement shall also be deemed to be a security
agreement within the meaning of

                                      -22-

<PAGE>

Articles 8 and 9 of the New York Uniform Commercial Code; (2) the conveyance
provided for in Section 4 hereof shall be deemed to be a grant by the Seller to
the Purchaser of a security interest in all of the Seller's right, title and
interest in and to the Mortgage Loans and all amounts payable to the holders of
the Mortgage Loans in accordance with the terms thereof and all proceeds of the
conversion, voluntary or involuntary, of the foregoing into cash, instruments,
securities or other property, including without limitation all amounts, other
than investment earnings, from time to time held or invested in the Collection
Account whether in the form of cash, instruments, securities or other property;
(3) the possession by the Purchaser or its agent of Mortgage Notes, the related
Mortgages and such other items of property that constitute instruments, money,
negotiable documents or chattel paper shall be deemed to be "possession" by the
secured party for purposes of perfecting the security interest pursuant to the
New York Uniform Commercial Code; and (4) notifications to persons holding such
property and acknowledgments, receipts or confirmations from persons holding
such property shall be deemed notifications to, or acknowledgments, receipts or
confirmations from, financial intermediaries, bailees or agents (as applicable)
of the Purchaser for the purpose of perfecting such security interest under
applicable law. Any assignment of the interest of the Purchaser pursuant to
Section 4(d) hereof shall also be deemed to be an assignment of any security
interest created hereby. The Seller and the Purchaser shall, to the extent
consistent with this Agreement, take such actions as may be necessary to ensure
that, if this Agreement were deemed to create a security interest in the
Mortgage Loans, such security interest would be deemed to be a perfected
security interest of first priority under applicable law and will be maintained
as such throughout the term of this Agreement and the Pooling and Servicing
Agreement.

                  The NIMS Insurer, if any, shall be a third party beneficiary
hereof and may enforce the terms hereof as if a party hereto.

                                      -23-

<PAGE>

                  IN WITNESS WHEREOF, the Originator, the Purchaser and the
Seller have caused their names to be signed by their respective officers
thereunto duly authorized as of the date first above written.

                                         MORTGAGE ASSET SECURITIZATION
                                         TRANSACTIONS, INC.

                                         By:________________________________
                                         Name:
                                         Title:

                                         By:________________________________
                                         Name:
                                         Title:

                                         UBS WARBURG REAL ESTATE SECURITIES INC.

                                         By:________________________________
                                         Name:
                                         Title:

                                         By:________________________________
                                         Name:
                                         Title:

                                         OPTION ONE MORTGAGE CORPORATION

                                         By:________________________________
                                         Name:
                                         Title:

<PAGE>

                                    EXHIBIT E
                                    ---------

                        REQUEST FOR RELEASE OF DOCUMENTS

To:      Wells Fargo Bank Minnesota, National Association,
         1015 10th Avenue S.E.
         Minneapolis, MN 55414
         Attn: Inventory Control

                  Re:      Pooling and Servicing Agreement, dated as of February
                           1, 2003, among Mortgage Asset Securitization
                           Transactions, Inc., Option One Mortgage Corporation
                           and Wells Fargo Bank Minnesota, National Association,
                           Mortgage Pass-Through Certificates, Series 2003-OPT1
                           -----------------------------------------------------

         In connection with the administration of the Mortgage Loans held by you
as Trustee pursuant to the above-captioned Pooling and Servicing Agreement, we
request the release, and hereby acknowledge receipt of the Trustee's Mortgage
File Or 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:

Address to which Trustee should
deliver the Trustee's Mortgage File:

                                      E-1-1

<PAGE>

                                By:__________________________________
                                         (authorized signer)

                                Issuer:__________________________________

                                Address:__________________________________

                                Date:__________________________________

Trustee
-------

Wells Fargo Bank Minnesota, National Association
                Please acknowledge the execution of the above request by your
                signature and date below:

                _____________________                       ___________
                Signature                                   Date

                Documents returned to Trustee:

                _____________________                       ___________
                Trustee                                     Date

                                      E-1-2

<PAGE>

                                   EXHIBIT F-1
                                   -----------

                    FORM OF TRANSFEROR REPRESENTATION LETTER

                                                        [Date]

Wells Fargo Bank Minnesota, National Association
9062 Old Annapolis Road
Columbia, Maryland 21045-1951

                  Re:      MASTR Asset Backed Securities Trust, Series
                           2003-OPT1, Mortgage Pass-Through Certificates, Class
                           ___, representing a ___% Class ___ Percentage
                           Interest
                           ----------------------------------------------------

Ladies and Gentlemen:

                  In connection with the transfer by ________________ (the
"Transferor") to ________________ (the "Transferee") of the captioned mortgage
pass-through certificates (the "Certificates"), the Transferor hereby certifies
as follows:

                  Neither the Transferor nor anyone acting on its behalf has (a)
offered, pledged, sold, disposed of or otherwise transferred any Certificate,
any interest in any Certificate or any other similar security to any person in
any manner, (b) has solicited any offer to buy or to accept a pledge,
disposition or other transfer of any Certificate, any interest in any
Certificate or any other similar security from any person in any manner, (c) has
otherwise approached or negotiated with respect to any Certificate, any interest
in any Certificate or any other similar security with any person in any manner,
(d) has made any general solicitation by means of general advertising or in any
other manner, (e) has taken any other action, that (in the case of each of
subclauses (a) through (e) above) would constitute a distribution of the
Certificates under the Securities Act of 1933, as amended (the "1933 Act"), or
would render the disposition of any Certificate a violation of Section 5 of the
1933 Act or any state securities law or would require registration or
qualification pursuant thereto. The Transferor will not act, nor has it
authorized or will it authorize any person to act, in any manner set forth in
the foregoing sentence with respect to any Certificate. The Transferor will not
sell or otherwise transfer any of the Certificates, except in compliance with
the provisions of that certain Pooling and Servicing Agreement, dated as of
February 1, 2003, among Mortgage Asset Securitization Transactions, Inc. as
Depositor, Option One Mortgage Corporation as Master Servicer and Wells Fargo
Bank Minnesota, National Association as Trustee (the "Pooling and Servicing
Agreement"), pursuant to which Pooling and Servicing Agreement the Certificates
were issued.

                                      F-1-1

<PAGE>

                  Capitalized terms used but not defined herein shall have the
meanings assigned thereto in the Pooling and Servicing Agreement.

                                                    Very truly yours,

                                                    [Transferor]

                                                    By:_________________________
                                                    Name:
                                                    Title:

                                      F-1-2

<PAGE>

                    FORM OF TRANSFEREE REPRESENTATION LETTER

                                                          [Date]

Wells Fargo Bank Minnesota, National Association
9062 Old Annapolis Road
Columbia, Maryland 21045-1951

                  Re:      MASTR Asset Backed Securities Trust, Series
                           2003-OPT1, Mortgage Pass-Through Certificates, Class
                           ___, representing a ___% Class ___ Percentage
                           Interest
                           ----------------------------------------------------

Ladies and Gentlemen:

                  In connection with the purchase from ______________________
(the "Transferor") on the date hereof of the captioned trust certificates (the
"Certificates"), _______________ (the "Transferee") hereby certifies as follows:

                  1. The Transferee is a "qualified institutional buyer" as that
term is defined in Rule 144A ("Rule 144A") under the Securities Act of 1933 (the
"1933 Act") and has completed either of the forms of certification to that
effect attached hereto as Annex 1 or Annex 2. The Transferee is aware that the
sale to it is being made in reliance on Rule 144A. The Transferee is acquiring
the Certificates for its own account or for the account of a qualified
institutional buyer, and understands that such Certificate may be resold,
pledged or transferred only (i) to a person reasonably believed to be a
qualified institutional buyer that purchases for its own account or for the
account of a qualified institutional buyer to whom notice is given that the
resale, pledge or transfer is being made in reliance on Rule 144A, or (ii)
pursuant to another exemption from registration under the 1933 Act.

                  2. The Transferee has been furnished with all information
regarding (a) the Certificates and distributions thereon, (b) the nature,
performance and servicing of the Mortgage Loans, (c) the Pooling and Servicing
Agreement referred to below, and (d) any credit enhancement mechanism associated
with the Certificates, that it has requested.

                  All capitalized terms used but not otherwise defined herein
have the respective meanings assigned thereto in the Pooling and Servicing
Agreement, dated as of February 1, 2003, among Mortgage Asset Securitization
Transactions, Inc. as Depositor, Option One Mortgage Corporation as Master
Servicer and Wells Fargo Bank Minnesota, National Association as Trustee,
pursuant to which the Certificates were issued.

                                                        [TRANSFEREE]

                                                        By:_____________________
                                                        Name:
                                                        Title:

                                      F-1-3

<PAGE>

                                                          ANNEX 1 TO EXHIBIT F-1
                                                          ----------------------

            QUALIFIED INSTITUTIONAL BUYER STATUS UNDER SEC RULE 144A
            --------------------------------------------------------

          [For Transferees Other Than Registered Investment Companies]

                  The undersigned hereby certifies as follows to [name of
Transferor] (the "Transferor") and Wells Fargo Bank Minnesota, National
Association, as Trustee, with respect to the mortgage pass-through certificates
(the "Certificates") described in the Transferee Certificate to which this
certification relates and to which this certification is an Annex:

                  1. As indicated below, the undersigned is the President, Chief
Financial Officer, Senior Vice President or other executive officer of the
entity purchasing the Certificates (the "Transferee").

                  2. In connection with purchases by the Transferee, the
Transferee is a "qualified institutional buyer" as that term is defined in Rule
144A under the Securities Act of 1933 ("Rule 144A") because (i) the Transferee
owned and/or invested on a discretionary basis $______________________1 in
securities (except for the excluded securities referred to below) as of the end
of the Transferee's most recent fiscal year (such amount being calculated in
accordance with Rule 144A) and (ii) the Transferee satisfies the criteria in the
category marked below.

         ___ CORPORATION, ETC. The Transferee is a corporation (other than a
bank, savings and loan association or similar institution), Massachusetts or
similar business trust, partnership, or any organization described in Section
501(c)(3) of the Internal Revenue Code of 1986.

         ___ BANK. The Transferee (a) is a national bank or banking institution
organized under the laws of any State, territory or the District of Columbia,
the business of which is substantially confined to banking and is supervised by
the State or territorial banking commission or similar official or is a foreign
bank or equivalent institution, and (b) has an audited net worth of at least
$25,000,000 as demonstrated in its latest annual financial statements, a copy of
which is attached hereto.

         ___ SAVINGS AND LOAN. The Transferee (a) is a savings and loan
association, building and loan association, cooperative bank, homestead
association or similar institution, which is supervised and examined by a State
or Federal authority having supervision over any such institutions or is a
foreign savings and loan association or equivalent institution and (b) has an
audited net worth of at least

         ___ BROKER-DEALER. The Transferee is a dealer registered pursuant to
Section 15 of the Securities Exchange Act of 1934.

--------

1        Transferee must own and/or invest on a discretionary basis at least
         $100,000,000 in securities unless Transferee is a dealer, and, in that
         case, Transferee must own and/or invest on a discretionary basis at
         least $10,000,000 in securities. $25,000,000 as demonstrated in its
         latest annual financial statements, A COPY OF WHICH IS ATTACHED HERETO.

                                      F-1-4

<PAGE>

         ___ INSURANCE COMPANY. The Transferee is an insurance company whose
primary and predominant business activity is the writing of insurance or the
reinsuring of risks underwritten by insurance companies and which is subject to
supervision by the insurance commissioner or a similar official or agency of a
State, territory or the District of Columbia.

         ___ STATE OR LOCAL PLAN. The Transferee is a plan established and
maintained by a State, its political subdivisions, or any agency or
instrumentality of the State or its political subdivisions, for the benefit of
its employees.

         ___ ERISA PLAN. The Transferee is an employee benefit plan within the
meaning of Title I of the Employee Retirement Income Security Act of 1974.

         ___ INVESTMENT ADVISOR. The Transferee is an investment advisor
registered under the Investment Advisers Act of 1940.

                  3. The term "SECURITIES" as used herein DOES NOT INCLUDE (i)
securities of issuers that are affiliated with the Transferee, (ii) securities
that are part of an unsold allotment to or subscription by the Transferee, if
the Transferee is a dealer, (iii) securities issued or guaranteed by the U.S. or
any instrumentality thereof, (iv) bank deposit notes and certificates of
deposit, (v) loan participations, (vi) repurchase agreements, (vii) securities
owned but subject to a repurchase agreement and (viii) currency, interest rate
and commodity swaps.

                  4. For purposes of determining the aggregate amount of
securities owned and/or invested on a discretionary basis by the Transferee, the
Transferee used the cost of such securities to the Transferee and did not
include any of the securities referred to in the preceding paragraph. Further,
in determining such aggregate amount, the Transferee may have included
securities owned by subsidiaries of the Transferee, but only if such
subsidiaries are consolidated with the Transferee in its financial statements
prepared in accordance with generally accepted accounting principles and if the
investments of such subsidiaries are managed under the Transferee's direction.
However, such securities were not included if the Transferee is a
majority-owned, consolidated subsidiary of another enterprise and the Transferee
is not itself a reporting company under the Securities Exchange Act of 1934.

                  5. The Transferee acknowledges that it is familiar with Rule
144A and understands that the Transferor and other parties related to the
Certificates are relying and will continue to rely on the statements made herein
because one or more sales to the Transferee may be in reliance on Rule 144A.

         ___      ___      Will the Transferee be purchasing the Certificates
         Yes      No       only for the Transferee's own account?

                  6. If the answer to the foregoing question is "no", the
Transferee agrees that, in connection with any purchase of securities sold to
the Transferee for the account of a third party (including any separate account)
in reliance on Rule 144A, the Transferee will only purchase for the account of a
third party that at the time is a "qualified institutional buyer" within the
meaning of Rule 144A. In addition, the Transferee agrees that the Transferee
will not purchase securities for a third

                                      F-1-5

<PAGE>

party unless the Transferee has obtained a current representation letter from
such third party or taken other appropriate steps contemplated by Rule 144A to
conclude that such third party independently meets the definition of "qualified
institutional buyer" set forth in Rule 144A.

                  7. The Transferee will notify each of the parties to which
this certification is made of any changes in the information and conclusions
herein. Until such notice is given, the Transferee's purchase of the
Certificates will constitute a reaffirmation of this certification as of the
date of such purchase. In addition, if the Transferee is a bank or savings and
loan as provided above, the Transferee agrees that it will furnish to such
parties updated annual financial statements promptly after they become
available.

Dated:

                                           ____________________________________
                                           Print Name of Transferee

                                           By:_________________________________
                                           Name:
                                           Title:

                                      F-1-6

<PAGE>

                                                          ANNEX 2 TO EXHIBIT F-1
                                                          ----------------------

            QUALIFIED INSTITUTIONAL BUYER STATUS UNDER SEC RULE 144A
            --------------------------------------------------------

           [For Transferees That Are Registered Investment Companies]

                  The undersigned hereby certifies as follows to [name of
Transferor] (the "Transferor") and Wells Fargo Bank Minnesota, National
Association, as Trustee, with respect to the mortgage pass- through certificates
(the "Certificates") described in the Transferee Certificate to which this
certification relates and to which this certification is an Annex:

                  1. As indicated below, the undersigned is the President, Chief
Financial Officer or Senior Vice President of the entity purchasing the
Certificates (the "Transferee") or, if the Transferee is a "qualified
institutional buyer" as that term is defined in Rule 144A under the Securities
Act of 1933 ("Rule 144A") because the Transferee is part of a Family of
Investment Companies (as defined below), is such an officer of the investment
adviser (the "Adviser").

                  2. In connection with purchases by the Transferee, the
Transferee is a "qualified institutional buyer" as defined in Rule 144A because
(i) the Transferee is an investment company registered under the Investment
Company Act of 1940, and (ii) as marked below, the Transferee alone, or the
Transferee's Family of Investment Companies, owned at least $100,000,000 in
securities (other than the excluded securities referred to below) as of the end
of the Transferee's most recent fiscal year. For purposes of determining the
amount of securities owned by the Transferee or the Transferee's Family of
Investment Companies, the cost of such securities was used.

         ____              The Transferee owned $___________________ in
                           securities (other than the excluded securities
                           referred to below) as of the end of the Transferee's
                           most recent fiscal year (such amount being calculated
                           in accordance with Rule 144A).

         ____              The Transferee is part of a Family of Investment
                           Companies which owned in the aggregate
                           $______________ in securities (other than the
                           excluded securities referred to below) as of the end
                           of the Transferee's most recent fiscal year (such
                           amount being calculated in accordance with Rule
                           144A).

                  3. The term "FAMILY OF INVESTMENT COMPANIES" as used herein
means two or more registered investment companies (or series thereof) that have
the same investment adviser or investment advisers that are affiliated (by
virtue of being majority owned subsidiaries of the same parent or because one
investment adviser is a majority owned subsidiary of the other).

                  4. The term "SECURITIES" as used herein does not include (i)
securities of issuers that are affiliated with the Transferee or are part of the
Transferee's Family of Investment Companies, (ii) securities issued or
guaranteed by the U.S. or any instrumentality thereof, (iii) bank deposit notes
and certificates of deposit, (iv) loan participations, (v) repurchase
agreements, (vi) securities owned but subject to a repurchase agreement and
(vii) currency, interest rate and commodity swaps.

                                      F-1-7

<PAGE>

                  5. The Transferee is familiar with Rule 144A and understands
that the parties to which this certification is being made are relying and will
continue to rely on the statements made herein because one or more sales to the
Transferee will be in reliance on Rule 144A. In addition, the Transferee will
only purchase for the Transferee's own account.

                  6. The undersigned will notify the parties to which this
certification is made of any changes in the information and conclusions herein.
Until such notice, the Transferee's purchase of the Certificates will constitute
a reaffirmation of this certification by the undersigned as of the date of such
purchase.

Dated:

                                           ___________________________________
                                           Print Name of Transferee or Advisor

                                           By:________________________________
                                           Name:
                                           Title:

                                           IF AN ADVISER:

                                           ___________________________________
                                           Print Name of Transferee

                                      F-1-8

<PAGE>

                    FORM OF TRANSFEREE REPRESENTATION LETTER
                    ----------------------------------------

                  The undersigned hereby certifies on behalf of the purchaser
named below (the "Purchaser") as follows:

                  1.  I am an executive officer of the Purchaser.

                  2. The Purchaser is a "qualified institutional buyer", as
defined in Rule 144A, ("Rule 144A") under the Securities Act of 1933, as
amended.

                  3. As of the date specified below (which is not earlier than
the last day of the Purchaser's most recent fiscal year), the amount of
"securities", computed for purposes of Rule 144A, owned and invested on a
discretionary basis by the Purchaser was in excess of $100,000,000.

                                                    Name of Purchaser

                                                    __________________________

                                                    By:_________________________
                                                    Name:
                                                    Title:

Date of this certificate:

Date of information provided in paragraph 3

                                      F-1-9

<PAGE>

                                   EXHIBIT F-2
                                   -----------

                    FORM OF TRANSFER AFFIDAVIT AND AGREEMENT

STATE OF NEW YORK                   )

COUNTY OF NEW YORK                  )

                  __________________________, being duly sworn, deposes,
represents and warrants as follows:

                  1. I am a ______________________ of __________________________
(the "Owner") a corporation duly organized and existing under the laws of
______________, the record owner of MASTR Asset Backed Securities Trust, Series
2003-OPT1, Mortgage Pass-Through Certificates, Class R Certificates, (the "Class
R Certificates"), on behalf of whom I make this affidavit and agreement.
Capitalized terms used but not defined herein have the respective meanings
assigned thereto in the Pooling and Servicing Agreement pursuant to which the
Class R Certificates were issued.

                  2. The Owner (i) is and will be a "Permitted Transferee" as of
____________, 20__ and (ii) is acquiring the Class R Certificates for its own
account or for the account of another Owner from which it has received an
affidavit in substantially the same form as this affidavit. A "Permitted
Transferee" is any person other than a "disqualified organization" or a
possession of the United States. For this purpose, a "disqualified organization"
means the United States, any state or political subdivision thereof, any agency
or instrumentality of any of the foregoing (other than an instrumentality all of
the activities of which are subject to tax and, except for the Federal Home Loan
Mortgage Corporation, a majority of whose board of directors is not selected by
any such governmental entity) or any foreign government, international
organization or any agency or instrumentality of such foreign government or
organization, any rural electric or telephone cooperative, or any organization
(other than certain farmers' cooperatives) that is generally exempt from federal
income tax unless such organization is subject to the tax on unrelated business
taxable income.

                  3. The Owner is aware (i) of the tax that would be imposed on
transfers of the Class R Certificates to disqualified organizations under the
Internal Revenue Code of 1986 that applies to all transfers of the Class R
Certificates after March 31, 1988; (ii) that such tax would be on the transferor
or, if such transfer is through an agent (which person includes a broker,
nominee or middleman) for a non-Permitted Transferee, on the agent; (iii) that
the person otherwise liable for the tax shall be relieved of liability for the
tax if the transferee furnishes to such person an affidavit that the transferee
is a Permitted Transferee and, at the time of transfer, such person does not
have actual knowledge that the affidavit is false; and (iv) that each of the
Class R Certificates may be a "noneconomic residual interest" within the meaning
of proposed Treasury regulations promulgated under 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 is to impede the assessment or collection of tax.

                                      F-2-1

<PAGE>

                  4. The Owner is aware of the tax imposed on a "pass-through
entity" holding the Class R Certificates if, at any time during the taxable year
of the pass-through entity, a non-Permitted Transferee is the record holder of
an interest in such entity. (For this purpose, a "pass-through entity" includes
a regulated investment company, a real estate investment trust or common trust
fund, a partnership, trust or estate, and certain cooperatives.)

                  5. The Owner is aware that the Trustee will not register the
transfer of any Class R Certificate unless the transferee, or the transferee's
agent, delivers to the Trustee, among other things, an affidavit in
substantially the same form as this affidavit. The Owner expressly agrees that
it will not consummate any such transfer if it knows or believes that any of the
representations contained in such affidavit and agreement are false.

                  6. The Owner consents to any additional restrictions or
arrangements that shall be deemed necessary upon advice of counsel to constitute
a reasonable arrangement to ensure that the Class R Certificates will only be
owned, directly or indirectly, by an Owner that is a Permitted Transferee.

                  7. The Owner's taxpayer identification number is
_________________.

                  8. The Owner has reviewed the restrictions set forth on the
face of the Class R Certificates and the provisions of Section 5.02(d) of the
Pooling and Servicing Agreement under which the Class R Certificates were issued
(in particular, clauses (iii)(A) and (iii)(B) of Section 5.02(d) which authorize
the Trustee to deliver payments to a person other than the Owner and negotiate a
mandatory sale by the Trustee in the event that the Owner holds such Certificate
in violation of Section 5.02(d)); and that the Owner expressly agrees to be
bound by and to comply with such restrictions and provisions.

                  9. The Owner is not acquiring and will not transfer the Class
R Certificates in order to impede the assessment or collection of any tax.

                  10. The Owner anticipates that it will, so long as it holds
the Class R Certificates, have sufficient assets to pay any taxes owed by the
holder of such Class R Certificates, and hereby represents to and for the
benefit of the person from whom it acquired the Class R Certificates that the
Owner intends to pay taxes associated with holding such Class R Certificates as
they become due, fully understanding that it may incur tax liabilities in excess
of any cash flows generated by the Class R Certificates.

                  11. The Owner has no present knowledge that it may become
insolvent or subject to a bankruptcy proceeding for so long as it holds the
Class R Certificates.

                  12. The Owner has no present knowledge or expectation that it
will be unable to pay any United States taxes owed by it so long as any of the
Certificates remain outstanding.

                  13. The Owner is not acquiring the Class R Certificates with
the intent to transfer the Class R Certificates to any person or entity that
will not have sufficient assets to pay any taxes

                                      F-2-2

<PAGE>

owed by the holder of such Class R Certificates, or that may become insolvent or
subject to a bankruptcy proceeding, for so long as the Class R Certificates
remain outstanding.

                  14. The Owner will, in connection with any transfer that it
makes of the Class R Certificates, obtain from its transferee the
representations required by Section 5.02(d) of the Pooling and Servicing
Agreement under which the Class R Certificate were issued and will not
consummate any such transfer if it knows, or knows facts that should lead it to
believe, that any such representations are false.

                  15. The Owner will, in connection with any transfer that it
makes of the Class R Certificates, deliver to the Trustee an affidavit, which
represents and warrants that it is not transferring the Class R Certificates to
impede the assessment or collection of any tax and that it has no actual
knowledge that the proposed transferee: (i) has insufficient assets to pay any
taxes owed by such transferee as holder of the Class R Certificates; (ii) may
become insolvent or subject to a bankruptcy proceeding for so long as the Class
R Certificates remains outstanding; and (iii) is not a "Permitted Transferee".

                  16. The Owner is a citizen or resident of the United States, a
corporation, partnership or other entity created or organized in, or under the
laws of, the United States or any political subdivision thereof, or an estate or
trust whose income from sources without the United States may be included in
gross income for United States federal income tax purposes regardless of its
connection with the conduct of a trade or business within the United States.

                  17. The Owner of the Class R Certificate, hereby agrees that
in the event that the Trust Fund created by the Pooling and Servicing Agreement
is terminated pursuant to Section 9.01 thereof, the undersigned shall assign and
transfer to the Holders of the Class CE Certificates (with respect to a
termination of REMIC I) any amounts in excess of par received in connection with
such termination. Accordingly, in the event of such termination, the Trustee is
hereby authorized to withhold any such amounts in excess of par and to pay such
amounts directly to the Holders of the Class CE Certificates. This agreement
shall bind and be enforceable against any successor, transferee or assigned of
the undersigned in the Class R Certificate. In connection with any transfer of
the Class R Certificate, the Owner shall obtain an agreement substantially
similar to this clause from any subsequent owner.

                                      F-2-3

<PAGE>

                  IN WITNESS WHEREOF, the Owner has caused this instrument to be
executed on its behalf, pursuant to the authority of its Board of Directors, by
its [Vice] President, attested by its [Assistant] Secretary, this ____ day of
__________, 20__.

                                                    [OWNER]

                                                    By:_________________________
                                                    Name:
                                                    Title:   [Vice] President

ATTEST:

By:_________________________________
Name:
Title:    [Assistant] Secretary

                  Personally appeared before me the above-named , known or
proved to me to be the same person who executed the foregoing instrument and to
be a [Vice] President of the Owner, 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 Owner.

                  Subscribed and sworn before me this ____ day of __________,
20___.

                                                   ____________________________
                                                            Notary Public

                                                   County of __________________
                                                   State of ___________________

                                                   My Commission expires:

                                      F-2-4

<PAGE>

                          FORM OF TRANSFEROR AFFIDAVIT
                          ----------------------------

STATE OF NEW YORK                   )

COUNTY OF NEW YORK                  )

                  __________________________, being duly sworn, deposes,
represents and warrants as follows:

                  1. I am a ____________________ of ____________________________
(the "Owner"), a corporation duly organized and existing under the laws of
______________, on behalf of whom I make this affidavit.

                  2. The Owner is not transferring the Class R Certificates (the
"Residual Certificates") to impede the assessment or collection of any tax.

                  3. The Owner has no actual knowledge that the Person that is
the proposed transferee (the "Purchaser") of the Residual Certificates: (i) has
insufficient assets to pay any taxes owed by such proposed transferee as holder
of the Residual Certificates; (ii) may become insolvent or subject to a
bankruptcy proceeding for so long as the Residual Certificates remain
outstanding and (iii) is not a Permitted Transferee.

                  4. The Owner understands that the Purchaser has delivered to
the Trustee a transfer affidavit and agreement in the form attached to the
Pooling and Servicing Agreement as Exhibit F-2. The Owner does not know or
believe that any representation contained therein is false.

                  5. At the time of transfer, the Owner has conducted a
reasonable investigation of the financial condition of the Purchaser as
contemplated by Treasury Regulations Section 1.860E-1(c)(4)(i) and, as a result
of that investigation, the Owner has determined that the Purchaser has
historically paid its debts as they became due and has found no significant
evidence to indicate that the Purchaser will not continue to pay its debts as
they become due in the future. The Owner understands that the transfer of a
Residual Certificate may not be respected for United States income tax purposes
(and the Owner may continue to be liable for United States income taxes
associated therewith) unless the Owner has conducted such an investigation.

                  6. Capitalized terms not otherwise defined herein shall have
the meanings ascribed to them in the Pooling and Servicing Agreement.

                                     F-2-5

<PAGE>

                  IN WITNESS WHEREOF, the Owner has caused this instrument to be
executed on its behalf, pursuant to the authority of its Board of Directors, by
its [Vice] President, attested by its [Assistant] Secretary, this ____ day of
___________, 20__.

                                                 [OWNER]

                                                 By:____________________________
                                                 Name:
                                                 Title:     [Vice] President

ATTEST:

By:______________________________
Name:
Title:   [Assistant] Secretary

                  Personally appeared before me the above-named , known or
proved to me to be the same person who executed the foregoing instrument and to
be a [Vice] President of the Owner, 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 Owner.

                  Subscribed and sworn before me this ____ day of __________,
20___.

                                                    ____________________________
                                                             Notary Public

                                                    County of __________________
                                                    State of ___________________

                                                    My Commission expires:

                                      F-2-6

<PAGE>

                                    EXHIBIT G
                                    ---------

            FORM OF CERTIFICATION WITH RESPECT TO ERISA AND THE CODE

                                                  _____________, 20__

Mortgage Asset Securitization Transactions, Inc.
1285 Avenue of the Americas
New York, New York 10019

Option One Mortgage Corporation
3 Ada
Irvine, California 92612

Wells Fargo Bank Minnesota, National Association
9062 Old Annapolis Road
Columbia, Maryland 21045-1951

                  Re:      MASTR Asset Backed Securities Trust, Series
                           2003-OPT1, Mortgage Pass-Through Certificates, Class
                           ___
                           ----------------------------------------------------

Dear Sirs:

                  _______________________ (the "Transferee") intends to acquire
from _____________________ (the "Transferor") $____________ Initial Certificate
Principal Balance of MASTR Asset Backed Securities Trust, Series 2003-OPT1,
Mortgage Pass-Through Certificates, Class [CE] [P] [R](the "Certificates"),
issued pursuant to a Pooling and Servicing Agreement (the "Pooling and Servicing
Agreement") dated as of February 1, 2003, among Mortgage Asset Securitization
Transactions, Inc. as depositor (the "Depositor"), Option One Mortgage
Corporation as master servicer (the "Master Servicer") and Wells Fargo Bank
Minnesota, National Association as trustee (the "Trustee"). Capitalized terms
used herein and not otherwise defined shall have the meanings assigned thereto
in the Pooling and Servicing Agreement. The Transferee hereby certifies,
represents and warrants to, and covenants with the Depositor, the Trustee and
the Master Servicer that:

         The Certificates (i) are not being acquired by, and will not be
transferred to, any employee benefit plan within the meaning of section 3(3) of
the Employee Retirement Income Security Act of 1974, as amended ("ERISA"), or
other retirement arrangement, including individual retirement accounts and
annuities, Keogh plans and bank collective investment funds and insurance
company general or separate accounts in which such plans, accounts or
arrangements are invested, that is subject to Section 406 of ERISA or Section
4975 of the Internal Revenue Code of 1986 (the "Code") (any of the foregoing, a
"Plan"), (ii) are not being acquired with "plan assets" of a Plan within the
meaning of the Department of Labor ("DOL") regulation, 29 C.F.R.ss.2510.3-101,
and (iii) will not be transferred to any entity that is deemed to be investing
in plan assets within the meaning of the DOL regulation at 29 C.F.R.ss.
2510.3-101.

                                       G-1

<PAGE>

                                                   Very truly yours,

                                                   _____________________________

                                                   By:__________________________
                                                   Name:
                                                   Title:

                                       G-2

<PAGE>

                                    EXHIBIT H

                     FORM OF REPORT PURSUANT TO SECTION 4.06

================================================================================

                       SECURITIES AND EXCHANGE COMMISSION

                             Washington, D.C. 20549

                                    Form 10-K

                                  Annual Report

                     Pursuant to Section 13 or 15(d) of the
                 Securities Exchange Act of 1934 (Fee Required)

                     For fiscal year ended ________________

                       Commission file number: 333-_______

                MORTGAGE ASSET SECURITIZATION TRANSACTIONS, INC.
            (as depositor under the Pooling and Servicing Agreement,
           dated as of February 1, 2003, providing for the issuance of
              Mortgage Pass-Through Certificates, Series 2003-OPT1)

                Mortgage Asset Securitization Transactions, Inc.
                ------------------------------------------------

             (Exact name of registrant as specified in its charter)
--------------------------------------------------------------------------------

           Delaware                                     [__]
           --------                                     ----
(State or Other Jurisdiction                            (I.R.S. Employer
of Incorporation)                                       Identification Number)

1285 Avenue of the Americas
New York, New York 10019                                10019
------------------------                                -----
(Address of Principal Executive Offices)                (Zip Code)

Registrant's telephone number, including area code: [___]
                                                    -----

================================================================================

                                       H-1

<PAGE>

Securities registered pursuant to Section 12(b) of the Act:

None

Securities registered pursuant to Section 12(g) of the Act:

None

Indicate whether the Registrant: (1) has filed all reports required to be filed
by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the
preceding 12 months (or for such shorter period that the registrant was required
to file such reports), and (2) has been subject to such filing requirements for
the past 90 days.

                                                         X YES       No
                                                        ---       ---
Item 1.  Business:

Not applicable

Item 2.  Properties:

Not applicable

Item 3.  Legal Proceedings:

None

Item 4.  Submission of Matters to a Vote of Security-Holders

None

Item 5.  Market for Registrant's Common Equity and Related Stockholder Matters

To the best knowledge of the registrant there is no established public trading
market for the certificates.

There are approximately _____ holders of record as of the end of the reporting
year.

Item 6.  Selected Financial Data.

Not applicable.

Item 7. Management's Discussion and Analysis of Financial Condition and Results
of Operations

Not applicable

                                       H-2

<PAGE>

Item 8.  Financial Statements and Supplementary Data.

Not applicable.

Item 9. Changes in and Disagreements With Accountants on Accounting and
Financial Disclosure

None

Item 10.

Not applicable

Item 11.  Executive Compensation

Not applicable

Item 12.  Security Ownership of Certain Beneficial Owners and Management

Not applicable

Item 13.  Certain Relationships and Related Transactions

Not applicable

Item 14.  Exhibits, Financial Statement Schedules, and Reports on Form 8-K

         a)       The company filed on Form 8-K, separately for each
                  distribution date, the distribution of funds related to the
                  trust for each of the following distribution dates:

                           Distribution Date               Form 8-K Filing Date
                           -----------------               --------------------
                           _________________               ________________
                           _________________               ________________
                           _________________               ________________

         b)       99.1     Annual Report of Independent Public Accountants' as
                           to master servicing activities or servicing
                           activities, as applicable

                           (a) Option One Mortgage Corporation, as Master
                           Servicer

                  99.2     Annual Statement of Compliance with obligations under
                           the Pooling and Servicing Agreement or servicing
                           agreement, as applicable, of:

                           (a) Option One Mortgage Corporation, as Master
                           Servicer

                                       H-3

<PAGE>

Such document (i) is not filed herewith since such document was not received by
the Reporting Person at least three business days prior to the due date of this
report; and (ii) will be included in an amendment to this report on Form 10-K/A
to be filed within 30 days of the Reporting Person's receipt of such document.

                                   Signatures

                  Pursuant to the requirements of Section 13 or 15(d) of the
Securities Exchange Act of 1934, the registrant has duly caused this report to
be signed on its behalf by the undersigned thereunto duly authorized.

Date: ___________

                                              Mortgage Asset Securitization
                                              Transactions, Inc., by Wells Fargo
                                              Bank Minnesota, National
                                              Association, as Trustee for MASTR
                                              Asset Backed Securities Trust,
                                              Series 2003- OPT1, Mortgage
                                              Pass-Through Certificates.

                                              By:_______________________________
                                              Name:
                                              Title:
                                              Company:

                                       H-4

<PAGE>

                                    EXHIBIT I

                          FORM OF LOST NOTE AFFIDAVIT

                              Loan #: ____________
                             Borrower: _____________

                               LOST NOTE AFFIDAVIT

                  I, as ____________________ of ______________________, a
_______________ corporation am authorized to make this Affidavit on behalf of
_____________________ (the "Seller"). In connection with the administration of
the Mortgage Loans held by ____________________, a _________________ corporation
as Seller on behalf of Mortgage Asset Securitization Transactions, Inc. (the
"Purchaser"), _____________________ (the "Deponent"), being duly sworn, deposes
and says that:

         1.       The Seller's address is:  _____________________
                                            _____________________
                                            _____________________

         2.       The Seller previously delivered to the Purchaser a signed
                  Initial Certification with respect to such Mortgage and/or
                  Assignment of Mortgage;

         3.       Such Mortgage Note and/or Assignment of Mortgage was assigned
                  or sold to the Purchaser by ________________________, a
                  ____________ corporation pursuant to the terms and provisions
                  of a Mortgage Loan Purchase Agreement dated as of __________
                  __, _____;

         4.       Such Mortgage Note and/or Assignment of Mortgage is not
                  outstanding pursuant to a request for release of Documents;

         5.       Aforesaid Mortgage Note and/or Assignment of Mortgage (the
                  "Original") has been lost;

         6.       Deponent has made or caused to be made a diligent search for
                  the Original and has been unable to find or recover same;

         7.       The Seller was the Seller of the Original at the time of the
                  loss; and

         8.       Deponent agrees that, if said Original should ever come into
                  Seller's possession, custody or power, Seller will immediately
                  and without consideration surrender the Original to the
                  Purchaser.

         9.       Attached hereto is a true and correct copy of (i) the Note,
                  endorsed in blank by the Mortgagee and (ii) the Mortgage or
                  Deed of Trust (strike one) which

                                       I-1

<PAGE>

                  secures the Note, which Mortgage or Deed of Trust is recorded
                  in the county where the property is located.

         10.      Deponent hereby agrees that the Seller (a) shall indemnify and
                  hold harmless the Purchaser, its successors and assigns,
                  against any loss, liability or damage, including reasonable
                  attorney's fees, resulting from the unavailability of any
                  Notes, including but not limited to any loss, liability or
                  damage arising from (i) any false statement contained in this
                  Affidavit, (ii) any claim of any party that has already
                  purchased a mortgage loan evidenced by the Lost Note or any
                  interest in such mortgage loan, (iii) any claim of any
                  borrower with respect to the existence of terms of a mortgage
                  loan evidenced by the Lost Note on the related property to the
                  fact that the mortgage loan is not evidenced by an original
                  note and (iv) the issuance of a new instrument in lieu thereof
                  (items (i) through (iv) above hereinafter referred to as the
                  "Losses") and (b) if required by any Rating Agency in
                  connection with placing such Lost Note into a Pass-Through
                  Transfer, shall obtain a surety from an insurer acceptable to
                  the applicable Rating Agency to cover any Losses with respect
                  to such Lost Note.

         11.      This Affidavit is intended to be relied upon by the Purchaser,
                  its successors and assigns. _____________________, a
                  ______________ corporation represents and warrants that is has
                  the authority to perform its obligations under this Affidavit
                  of Lost Note.

Executed this ____ day, of ___________ ______.

                                                     SELLER

                                                     By:______________________
                                                     Name:
                                                     Title:

                  On this _____ day of ________, _____, before me appeared
_________________ to me personally known, who being duly sworn did say that he
is the _____________________ of ____________________ a ______________
corporation and that said Affidavit of Lost Note was signed and sealed on behalf
of such corporation and said acknowledged this instrument to be the free act and
deed of said corporation.

                                           Signature:

                                           [Seal]

                                       I-2

<PAGE>

                                   EXHIBIT J-1

            FORM CERTIFICATION TO BE PROVIDED BY THE MASTER SERVICER
                                 WITH FORM 10-K

                  Re:      MASTR Asset Backed Securities Trust 2003-OPT1
                           Mortgage Pass Through Certificates, Series 2003-OPT1

                  I, _______________, the senior officer of Option One Mortgage
Corporation, certify that:

                  l. I have reviewed this annual report on Form 10-K, and all
reports on Form 8-K containing distribution and servicing reports filed in
respect of periods included in the year covered by this annual report, of
Mortgage Asset Securitization Transactions, Inc. (the "Registrant");

                  2. Based on my knowledge, the information in these reports,
taken as a whole, does 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 as of
the last day of the period covered by this annual report;

                  3. Based on my knowledge, the distribution information and the
servicing information required to be provided to the Trustee by the Master
Servicer under the Pooling and Servicing Agreement is included in these reports;

                  4. I am responsible for reviewing the activities performed by
the Master Servicer under the Pooling and Servicing Agreement and based upon my
knowledge and the annual compliance review required under the Pooling and
Servicing Agreement, and except as disclosed in the reports, the Master Servicer
has fulfilled its obligations under the Pooling and Servicing Agreement; and

                  5. The reports disclose all significant deficiencies relating
to the Master Servicer's compliance with the minimum servicing standards based
upon the report provided by an independent public accountant, after conducting a
review in compliance with the Uniform Single Attestation Program for Mortgage
Bankers or similar procedure, as set forth in the Pooling and Servicing
Agreement that is included in these reports.

                  In giving the certifications above, I have reasonably relied
on information provided to me by the following unaffiliated parties: Wells Fargo
Bank Minnesota, National Association.

                  Capitalized terms used but not defined herein have the
meanings ascribed to them in the Pooling and Servicing Agreement, dated February
1, 2003 (the "Pooling and Servicing Agreement"), among the Registrant as
depositor, Option One Mortgage Corporation as master servicer and Wells Fargo
Bank Minnesota, National Association as trustee.

                                       J-1

<PAGE>

                                       OPTION ONE MORTGAGE CORPORATION

                                       By:____________________________________
                                       Name:
                                       Title:
                                       Date:

                                       J-2

<PAGE>

                                   EXHIBIT J-2

        FORM OF CERTIFICATION TO BE PROVIDED TO DEPOSITOR BY THE TRUSTEE

                  Re:      MASTR Asset Backed Securities Trust 2003-OPT1
                           Mortgage Pass Through Certificates, Series 2003-OPT1

                  I, [identify the certifying individual], a [title] of Wells
Fargo Bank Minnesota, National Association, as Trustee, hereby certify to
Mortgage Asset Securitization Transactions, Inc. (the "Depositor"), and its
officers, directors and affiliates, and with the knowledge and intent that they
will rely upon this certification, that:

                  1. I have reviewed the annual report on Form 10-K for the
fiscal year [___], and all reports on Form 8-K containing distribution reports
filed in respect of periods included in the year covered by that annual report,
of the Depositor relating to the above-referenced trust;

                  2. Based on my knowledge, the information in these
distribution reports prepared by the Trustee, taken as a whole, does 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 as of the last day of the period
covered by that annual report; and

                  3. Based on my knowledge, the distribution information
required to be provided by the Trustee under the Pooling and Servicing Agreement
is included in these distribution reports.

                  Capitalized terms used but not defined herein have the
meanings ascribed to them in the Pooling and Servicing Agreement, dated February
1, 2003 (the "Pooling and Servicing Agreement"), among the Depositor as
depositor, Option One Mortgage Corporation as master servicer and Wells Fargo
Bank Minnesota, National Association as trustee.

                                         WELLS FARGO BANK MINNESOTA, NATIONAL
                                         ASSOCIATION, as Trustee

                                         By:__________________________________
                                         Name:
                                         Title:
                                         Date:

                                       J-3

<PAGE>

                                    EXHIBIT K
                                    ---------

                           LOSS MITIGATION PROCEDURES

                                       K-1

<PAGE>

                                   Schedule 1

                             MORTGAGE LOAN SCHEDULE

                                [FILED BY PAPER]

                                  Schedule 1-1

<PAGE>

                                   Schedule 2

                         SCHEDULE OF PREPAYMENT CHARGES

                             Available Upon Request

                                  Schedule 2-1

<PAGE>

                                   Schedule 3

                               PMI Mortgage Loans

                             Available Upon Request

                                  Schedule 2-2Exhibit 4.(b)

                                                             Executed in 6 Parts
                                                            Counterpart No. (  )

                              NATIONAL EQUITY TRUST

                        S&P 500 STRATEGY TRUST SERIES 20

                            REFERENCE TRUST AGREEMENT

      This Reference Trust Agreement dated April 2, 2003 among Prudential
Investment Management Services LLC, as Depositor, Prudential Securities
Incorporated, as Portfolio Supervisor, and The Bank of New York, as Trustee,
sets forth certain provisions in full and incorporates other provisions by
reference to the document entitled "National Equity Trust, Trust Indenture and
Agreement" (the "Basic Agreement") dated February 2, 2000. Such provisions as
are set forth in full herein and such provisions as are incorporated by
reference constitute a single instrument (the "Indenture").

                                WITNESSETH THAT:

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

                                    Part I.

                     STANDARD TERMS AND CONDITIONS OF TRUST

      Subject to the provisions of Part II hereof, all the provisions contained
in the Basic Agreement are herein incorporated by reference in their entirety
and shall be deemed to be a part of this instrument as fully and to the same
extent as though said provisions had been set forth in full in this instrument.

      A. Article I, entitled "Definitions," shall be amended as follows:

      (i) Section 1.01-Definitions shall be amended to add the following
definition at the end thereof:

<PAGE>

                                       -2-

      "Portfolio Supervisor" of the Trust shall have the meaning assigned to it
in Part II of the Reference Trust Agreement.

      B. Article III, entitled "Administration of Trust," shall be amended as
follows:

      (i) The third paragraph of Section 3.05-Distribution shall be amended by
deleting any reference to Depositor and replacing it with Portfolio Supervisor.

      (ii) Section 3.14-Deferred Sales Charge shall be amended to add the
following sentences at the end thereof:

      "References to Deferred Sales Charge in this Trust Indenture and Agreement
      shall include any Creation and Development Fee indicated in the prospectus
      for a Trust. The Creation and Development Fee shall be payable on each
      date so designated and in an amount determined as specified in the
      prospectus for a Trust."

      C. Article VIII, entitled "Depositor," shall be amended as follows:

      (i) Section 8.07-Compensation shall be amended by deleting any reference
to Depositor and replacing it with Portfolio Supervisor.

      D. Article IX, entitled "Additional Covenants; Miscellaneous Provisions,"
shall be amended as follows:

      (i) The first sentence of Section 9.05 - Written Notice shall be amended
by deleting the language "Prudential Securities Incorporated at One Seaport
Plaza, New York, New York 10292" and replacing it with "Prudential Investment
Management LLC at 100 Mulberry Street, Gateway Center Three, Newark, New Jersey
07102".

<PAGE>

                                       -3-

                                    Part II.

                      SPECIAL TERMS AND CONDITIONS OF TRUST

      The following special terms and conditions are hereby agreed to:

      A. The Trust is denominated National Equity Trust, S&P 500 Strategy Trust
Series 20.

      B. The Units of the Trust shall be subject to a deferred sales charge.

      C. The publicly traded stocks listed in Schedule A hereto are those which,
subject to the terms of this Indenture, have been or are to be deposited in
Trust under this Indenture as of the date hereof.

      D. The term "Depositor" shall mean Prudential Investment Management
Services LLC.

      E. The term "Portfolio Supervisor" shall mean Prudential Securities
Incorporated.

      F. The aggregate number of Units referred to in Sections 2.03 and 9.01 of
the Basic Agreement is 125,000 as of the date hereof.

      G. A Unit of the Trust is hereby declared initially equal to 1/125,000th
of the Trust.

      H. The term "First Settlement Date" shall mean April 8, 2003.

      I. The terms "Computation Day" and "Record Date" mean on the tenth day of
June 2003, September 2003, December 2003, and March 2004.

      J. The term "Distribution Date" shall mean on the twenty-fifth day of June
2003, September 2003, December 2003, and March 2004.

      K. The term "Termination Date" shall mean July 6, 2004.

      L. The Trustee's Annual Fee shall be $.90 (per 1,000 Units) for 49,999,999
and below Units outstanding, $.84 (per 1,000 Units) for 50,000,000 to 99,999,999
Units outstanding, $.78 (per 1,000 Units) for 100,000,000 to 199,999,999 Units
outstanding, and $.66 (per 1,000 Units) for Units in excess of 200,000,000
Units. In calculating the Trustee's annual fee, the fee applicable to the number
of units outstanding shall apply to all units outstanding.

      M. The Portfolio Supervisor's portfolio supervisory service fee shall be
$.15 per 1,000 Units.

               [Signatures and acknowledgments on separate pages]

<PAGE>

                                       -4-

The Schedule of Portfolio Securities in Part A of the prospectus included in
this Registration Statement for National Equity Trust, S&P 500 Strategy Trust
Series 20 is hereby incorporated by reference herein as Schedule A hereto.

<PAGE>

                                            PRUDENTIAL INVESTMENT MANAGEMENT
                                            SERVICES LLC,
                                            (Depositor)

                                            By /s/ Richard R. Hoffmann
                                               ---------------------------
                                               Richard R. Hoffmann
                                               Vice President

                                            PRUDENTIAL SECURITIES INCORPORATED
                                            (Portfolio Supervisor)

                                            By /s/ Richard R. Hoffmann
                                               ---------------------------
                                               Richard R. Hoffmann
                                               Vice President

<PAGE>

                                            THE BANK OF NEW YORK
                                            Trustee

                                            By: /s/ Brian Aarons
                                               ---------------------------
                                               Brian Aarons
                                              Title: Vice President

(SEAL)

ATTEST:

By: /s/ Dorothy Alencastro
    ------------------------------
        Dorothy Alencastro
        Title: Assistant Vice President

STATE OF NEW YORK      )
                         : ss.:
COUNTY OF NEW YORK     )

      I, Emanuel Lytle, Jr., a Notary Public in and for the said County in the
state aforesaid, do hereby certify that Brian Aarons and Dorothy Alencastro
personally known to me to be the same persons whose names are subscribed to the
foregoing instrument and personally known to me to be a Vice President and
Assistant Vice President, respectively of The Bank of New York, appeared before
me this day in person, and acknowledged that they signed, sealed with a
corporate seal of The Bank of New York, and delivered the said instrument as
their free and voluntary act as such Vice President and Assistant Vice
President, respectively, and as the free and voluntary act of The Bank of New
York, for the uses and purposes therein set forth.

      GIVEN, under my hand and notarial seal this 2nd day of April, 2003.

                                            /s/ Emanuel Lytle, Jr.
                                            ---------------------------------
                                            Emanuel Lytle, Jr.
                                            Notary Public

(SEAL)

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