Barclays Capital
                                                         5 The North Colonnade
                                                         Canary Wharf
                                                         London E14 4BB

                                                         Tel +44 (0)20 7623 2323

To:           Wells Fargo Bank, N.A. as master servicer on behalf of the Wells
              Fargo Mortgage Backed Securities 2006-16 Trust (such trust, the
              "Issuing Entity") created under the Pooling and Servicing
              Agreement (as defined below)
Attn:         Wells Fargo Bank, N.A.
              9062 Old Annapolis Road
              Columbia, Maryland 21045
              Client Manager - Wells Fargo Mortgage Backed Securities,
              Series 2006-16
              Telephone: 410-884-2000
              Facsimile: 410-715-2380
From:         BARCLAYS BANK PLC (LONDON HEAD OFFICE)
Attn:         5 The North Colonnade
              Canary Wharf
              E14 4BB
              Facsimile: 44(20) 77736461
              Phone: 44(20) 77736810
Date:         October 30, 2006
Reference:    1425591B/1425586B

Dear Sir/Madam,

The purpose of this letter agreement is to confirm the terms and conditions of
the transaction entered into between Wells Fargo Bank, N.A. as master servicer
(the "Master Servicer") under the Pooling and Servicing Agreement (as defined
below) on behalf of the Issuing Entity and Barclays Bank PLC (each a "party" and
together "the parties") on the Trade Date specified below (the "Transaction").
This letter agreement constitutes a "Confirmation" as referred to in the ISDA
Master Agreement specified in paragraph 1 below. In this Confirmation, "Party A"
means Barclays Bank PLC and "Party B" means Wells Fargo Bank, N.A. as Master
Servicer on behalf of the Issuing Entity.

The definitions and provisions contained in the 2000 ISDA Definitions, as
published by the International Swaps and Derivatives Association, Inc. (the
"Definitions"), are incorporated into this Confirmation. In the event of any
inconsistency between the Definitions and this Confirmation, this Confirmation
will govern.

Other capitalized terms used herein (but not otherwise defined) shall have the
meaning specified in that certain Pooling and Servicing Agreement (the "Pooling
and Servicing Agreement"), to be dated as of October 30, 2006, among Wells Fargo
Asset Securities Corporation, as depositor (the "Depositor"), Wells Fargo Bank,
N.A., as Master Servicer and HSBC Bank USA, National Association, as trustee.

1      This Confirmation evidences a complete binding agreement between the
       parties as to the terms of the Transaction to which this Confirmation
       relates. In addition, the parties agree that for the purposes of this
       Transaction, this Confirmation will supplement, form a part of, and be
       subject to an agreement in the form of the 1992 ISDA Master Agreement
       (Multicurrency-Cross Border) as if the parties had executed an agreement
       in such form (but without any Schedule except for the elections noted
       below) on the Trade Date of the Transaction (such agreement, the "Form
       Master Agreement"). In the event of any inconsistency between the
       provisions of the Form Master Agreement and this Confirmation, this
       Confirmation will prevail for the purpose of this Transaction.

       Each party represents to the other party and will be deemed to represent
       to the other party on the date on which it enters into this Transaction
       that (absent a written agreement between the parties that expressly
       imposes affirmative obligations to the contrary for that Transaction):

       (a)    Non-Reliance

              Each party has made its own independent decisions to enter into
              this Transaction and as to whether this Transaction is appropriate
              or proper for it based upon its own judgment and upon advice from
              such advisors as it has deemed necessary. It is not relying on any
              communication (written or oral) of the other party as investment
              advice or as a recommendation to enter into this Transaction; it
              being understood that information and explanations related to the
              terms and conditions of this Transaction shall not be considered
              investment advice or a recommendation to enter into this
              Transaction. Further, such party has not received from the other
              party any assurance or guarantee as to the expected results of
              this Transaction.

       (b)    Evaluation and Understanding

              It is capable of evaluating and understanding (on its own behalf
              or through independent professional advice), and understands and
              accepts, the terms, conditions and risks of this Transaction. It
              is also capable of assuming, and assumes, the financial and other
              risks of this Transaction.

       (c)    Status of Parties

              The other party is not acting as an agent, fiduciary or advisor
              for it in respect of this Transaction.

2      The terms of the particular Transaction to which this Confirmation
       relates are as follows:

 Notional Amount:                    With respect to any Calculation Period the
                                     amount set forth on Schedule A attached
                                     hereto.

 Trade Date:                         October 30, 2006

 Effective Date:                     October 25, 2006

 Termination Date:                   August 25, 2013

 Fixed Amounts:

 Fixed Rate Payer:                   Party B

 Fixed Rate Payer Payment Date:      October 30, 2006

 Fixed Amount:                       USD[_____]

 Floating Amounts:

 Floating Rate Payer:                Party A

 Cap Rate:                           4.4%

 Floating Rate Payer Period          The 25th day of each month of each year,
 End Dates:                          commencing on November 25, 2006, through
                                     and including the Termination Date, subject
                                     to no adjustment.

 Floating Rate Payer Payment Dates:  Early Payment shall be applicable. The
                                     Floating Rate Payer Payment Date shall be
                                     one Business Day prior to each Floating
                                     Rate Payer Period End Date.

 Floating Rate for Initial           To be determined.
 Calculation Period:

 Floating Rate Option:               USD-LIBOR-BBA; provided, however, if the
                                     Floating Rate Option for any Calculation
                                     Period is greater than 8.9% then the
                                     Floating Rate Option for such Calculation
                                     Period shall be deemed to be 8.9%.

 Floating Amount:                    To be determined in accordance with the
                                     following formula: the greater of (i)
                                     (Floating Rate Option - Cap Rate) *
                                     Notional Amount * Floating Rate Day Count
                                     Fraction and (ii) zero.

 Designated Maturity:                1 Month

 Spread:                             None

 Floating Rate Day Count Fraction:   30/360

 Reset Dates:                        The first day of each Calculation Period.

 Business Days for Payments:         New York

 Calculation Agent:                  Party A; provided, however, that if an
                                     Event of Default occurs with respect to
                                     Party A, then Party B shall be entitled to
                                     appoint a financial institution which would
                                     qualify as a Reference Market-Maker to act
                                     as Calculation Agent (such financial
                                     institution subject to Party A's consent).

3      Form Master Agreement

       (a)    "Specified Entity" means, in relation to Party A, for the purpose
              of Section 5(a)(v), Section 5(a)(vi), Section 5(a)(vii) and
              Section 5(b)(iv): Not Applicable.

       (b)    "Specified Entity" means, in relation to Party B, for the purpose
              of Section 5(a)(v), Section 5(a)(vi), Section 5(a)(vii) and
              Section 5(b)(iv): Not Applicable.

       (c)    "Specified Transaction" is not applicable to Party A or Party B
              for any purpose, and accordingly, Section 5(a)(v) shall not apply
              to Party A or Party B.

       (d)    The "Breach of Agreement" provisions of Section 5(a)(ii) of the
              Agreement will be inapplicable to Party A and Party B.

       (e)    The "Misrepresentation" provisions of Section 5(a)(v) of the
              Agreement will be inapplicable to Party A and Party B.

       (f)    The "Cross Default" provisions of Section 5(a)(vi) will not apply
              to Party A or Party B.

       (g)    The "Credit Event Upon Merger" provisions of Section 5(b)(iv) of
              the Form Master Agreement will not apply to Party A or to Party B.

       (h)    The "Automatic Early Termination" provision of Section 6(a) of the
              Form Master Agreement will not apply to Party A or to Party B.

       (i)    The Form Master Agreement will be governed by, and construed in
              accordance with, the laws of the State of New York without
              reference to its conflict of laws provisions (except for Sections
              5-1401 and 5-1402 of the New York General Obligations Law).

       (j)    The phrase "Termination Currency" means United States Dollars.

       (k)    For the purpose of Section 6(e) of the Form Master Agreement,
              Market Quotation and Second Method will apply.

4      Recording of Conversations

       Each party to this Transaction acknowledges and agrees to the tape
       (and/or other electronic) recording of conversations between the parties
       to this Transaction whether by one or other or both of the parties or
       their agents.

5      Credit Support Document

       In relation to Party A:   Credit Support Annex dated the date hereof and
                                 duly executed and delivered by Party A and
                                 Party B.

       In relation to Party B:   Not Applicable.

6      Credit Support Provider

       In relation to Party A:   Not Applicable, unless Party A has a person
                                 guarantee its payment obligations under this
                                 Agreement in order to remedy a Ratings Event,
                                 in which event such person shall be a Credit
                                 Support Provider.

       In relation to Party B:   Not Applicable.

7      Account Details

       Account for payments to Party A:

              Correspondent: BARCLAYS BANK PLC NEW YORK
              FEED: 026002574
              Beneficiary: BARCLAYS SWAPS
              Beneficiary Account: 050-01922-8

       Account for payments to Party B:

              Bank: Wells Fargo Bank, N.A.
              ABA#: 121000248
              Account Name: SAS Clearing
              Acct #: 3970771416
              FFC to: 50958601 - Class A-6 Reserve Fund

8      Offices

       The Office of Party A for this Transaction is:

              London

       The Office of Party B for this Transaction is:

              Columbia, MD

9      Additional Provisions

       Fully-Paid Transactions

              Notwithstanding the terms of Sections 5 and 6 of the Form Master
              Agreement, if at any time and so long as Party B shall have
              satisfied in full all its payment and delivery obligations under
              Section 2(a)(i) of the Form Master Agreement and shall at the time
              have no future payment or delivery obligations, whether absolute
              or contingent, under such Section, then unless Party A is required
              pursuant to appropriate proceedings to return to Party B or
              otherwise returns to Party B (upon demand of Party B, or
              otherwise) any portion of any such payment or delivery: (i) the
              occurrence of an event described in Section 5(a) of the Form
              Master Agreement with respect to Party B shall not constitute an
              Event of Default or a Potential Event of Default with respect to
              Party B as the Defaulting Party; and (ii) Party A shall be
              entitled to designate an Early Termination Date pursuant to
              Section 6 of the Form Master Agreement only as a result of the
              occurrence of a Termination Event set forth in (i) either Section
              5(b)(i) or 5(b)(ii) of the Form Master Agreement with respect to
              Party A as the Affected Party or (ii) Section 5(b)(iii) of the
              Form Master Agreement with respect to Party A as the Burdened
              Party.

10     Compliance with Regulation AB

       (a)    Party A acknowledges that for so long as there are reporting
              obligations with respect to this Transaction under Regulation AB,
              the Depositor, acting on behalf of the Issuing Entity, is required
              under Regulation AB under the Securities Act of 1933, as amended,
              and the Securities Exchange Act of 1934, as amended ("Regulation
              AB"), to disclose certain information set forth in Regulation AB
              regarding Party A or its group of affiliated entities, if
              applicable, depending on the aggregate "significance percentage"
              of this Agreement and any other derivative contracts between Party
              A or its group of affiliated entities, if applicable, and Party B,
              as calculated from time to time in accordance with Item 1115 of
              Regulation AB.

       (b)    If the Depositor determines, reasonably and in good faith, that
              the significance percentage of this Agreement has increased to
              eight (8) percent or more but less than eighteen (18) percent,
              then the Depositor may request on the date of such determination
              (or, if such date of determination is not a Business Day, the
              immediately following Business Day) from Party A the same
              information set forth in Item 1115(b)(1) of Regulation AB that
              would have been required if the significance percentage had in
              fact increased to ten (10) percent, along with any necessary
              auditors' consent (such request, a "10% Cap Disclosure Request"
              and such requested information, subject to the last sentence of
              this paragraph, is the "10% Cap Financial Disclosure"). Party B or
              the Depositor shall provide Party A with the calculations and any
              other information reasonably requested by Party A with respect to
              the Depositor's determination that led to the 10% Cap Disclosure
              Request. The parties hereto further agree that the 10% Cap
              Financial Disclosure provided to meet the 10% Cap Disclosure
              Request may be, solely at Party A's option, either the information
              set forth in Item 1115(b)(1) or Item 1115(b)(2) of Regulation AB.

       (c)    Upon the occurrence of a 10% Cap Disclosure Request, Party A, at
              its own expense, shall (i) provide the Depositor with the 10% Cap
              Financial Disclosure, (ii) subject to Rating Agency Confirmation,
              secure another entity to replace Party A as party to this
              Agreement on terms substantially similar to this Agreement which
              entity is able to (A) provide the 10% Cap Financial Disclosure and
              (B) provide an indemnity to the Depositor, reasonably satisfactory
              to the Depositor, in relation to the 10% Cap Financial Disclosure
              or (iii) subject to Rating Agency Confirmation, obtain a guaranty
              of Party A's obligations under this Agreement from an affiliate of
              Party A that is able to (A) provide the 10% Cap Financial
              Disclosure, such that disclosure provided in respect of the
              affiliate will, in the judgment of counsel to the Depositor,
              satisfy any disclosure requirements applicable to Party A, and
              cause such affiliate to provide 10% Cap Financial Disclosure and
              (B) provide an indemnity to the Depositor, reasonably satisfactory
              to the Depositor, in relation to the 10% Cap Financial Disclosure.
              Any such 10% Cap Financial Disclosure provided pursuant to this
              paragraph (c) shall be in a form suitable for conversion to the
              format required for filing by the Depositor with the Securities
              and Exchange Commission via the Electronic Data Gathering and
              Retrieval System (EDGAR). If permitted by Regulation AB, any
              required 10% Cap Financial Disclosure may be provided by
              incorporation by reference from reports filed pursuant to the
              Securities Exchange Act.

       (d)    If the Depositor determines, reasonably and in good faith, that
              the significance percentage of this Agreement has increased to
              eighteen (18) percent or more, then the Depositor may request on
              the date of such determination (or, if such date of determination
              is not a Business Day, the immediately following Business Day)
              from Party A the same information set forth in Item 1115(b)(2) of
              Regulation AB that would have been required if the significance
              percentage had in fact increased to twenty (20) percent, along
              with any necessary auditors consent (such request, a "20% Cap
              Disclosure Request" and such requested information is the "20% Cap
              Financial Disclosure"). Party B or the Depositor shall provide
              Party A with the calculations and any other information reasonably
              requested by Party A with respect to the Depositor's determination
              that led to the 20% Cap Disclosure Request.

       (e)    Upon the occurrence of a 20% Cap Disclosure Request, Party A, at
              its own expense, shall (i) provide the Depositor with the 20% Cap
              Financial Disclosure, (ii) subject to Rating Agency Confirmation,
              secure another entity to replace Party A as party to this
              Agreement on terms substantially similar to this Agreement which
              entity is able to (A) provide the 20% Cap Financial Disclosure and
              (B) provide an indemnity to the Depositor, reasonably satisfactory
              to the Depositor, in relation to the 20% Cap Financial Disclosure
              or (iii) subject to Rating Agency Confirmation, obtain a guaranty
              of Party A's obligations under this Agreement from an affiliate of
              Party A that is able to (A) provide the 20% Cap Financial
              Disclosure, such that disclosure provided in respect of the
              affiliate will, in the judgment of counsel to the Depositor,
              satisfy any disclosure requirements applicable to Party A, and
              cause such affiliate to provide 20% Cap Financial Disclosure and
              (B) provide an indemnity to the Depositor, reasonably satisfactory
              to the Depositor, in relation to the 20% Cap Financial Disclosure.
              Any such 20% Cap Financial Disclosure provided pursuant to this
              paragraph (e) shall be in a form suitable for conversion to the
              format required for filing by the Depositor with the Securities
              and Exchange Commission via the Electronic Data Gathering and
              Retrieval System (EDGAR). If permitted by Regulation AB, any
              required 20% Cap Financial Disclosure may be provided by
              incorporation by reference from reports filed pursuant to the
              Securities Exchange Act.

11     Additional Termination Events

       The following Additional Termination Events will apply:

       (a)    a Ratings Event has occurred and Party A has not, within thirty
              (30) days, complied with Section 12 below, then an Additional
              Termination Event shall have occurred with respect to Party A and
              Party A shall be the sole Affected Party with respect to such
              Additional Termination Event.

       (b)    If (A) the Depositor still has a reporting obligation with respect
              to this Transaction pursuant to Regulation AB and (B) Party A has
              not, within 30 days after receipt of a 10% Cap Disclosure Request
              complied with the provisions set forth in clauses (b) and (c) of
              Paragraph 10 above (provided that if the significance percentage
              is 10% or more and less than 20% when the 10% Cap Disclosure
              Request is made or reaches 10% after a 10% Cap Disclosure Request
              has been made to Party A, Party A must comply with the provisions
              set forth in clauses (b) and (c) of Paragraph 10 above within 3
              calendar days of Party A being informed of the significance
              percentage reaching 10% or more), then an Additional Termination
              Event shall have occurred with respect to Party A and Party A
              shall be the sole Affected Party with respect to such Additional
              Termination Event.

       (c)    If (A) the Depositor still has a reporting obligation with respect
              to this Transaction pursuant to Regulation AB and (B) Party A has
              not, within 30 days after receipt of a 20% Cap Disclosure Request
              complied with the provisions set forth in clauses (d) and (e) of
              Paragraph 10 above (provided that if the significance percentage
              is 20% or more when the 20% Cap Disclosure Request is made or
              reaches 20% after a 20% Cap Disclosure Request has been made to
              Party A, Party A must comply with the provisions set forth in
              clauses (d) and (e) of Paragraph 10 above within 3 calendar days
              of Party A being informed of the significance percentage reaching
              20% or more), then an Additional Termination Event shall have
              occurred with respect to Party A and Party A shall be the sole
              Affected Party with respect to such Additional Termination Event.

12     Ratings Event

       If a Ratings Event (as defined below) occurs with respect to Party A (or
       any applicable Credit Support Provider), then Party A shall, at its own
       expense, (i) assign this Transaction within thirty (30) days of such
       Ratings Event to a third party that meets or exceeds, or as to which any
       applicable credit support provider meets or exceeds, the Approved Ratings
       Thresholds (as defined below) on terms substantially similar to this
       Confirmation, which party is approved by Party B, which approval shall
       not be unreasonably withheld, (ii) obtain a guaranty of, or a contingent
       agreement of, another person with the Approval Rating Thresholds to honor
       Party A's obligations under this Agreement, provided that such other
       person is approved by Party B, such approval not to be unreasonably
       withheld, (iii) post collateral under agreements and other instruments
       satisfactory to Fitch Ratings ("Fitch"), Standard & Poor's, a division of
       The McGraw-Hill Companies ("S&P") and Moody's Investor Service, Inc.
       ("Moody's"), which will be sufficient to restore the immediately prior
       ratings of the Certificates, or (iv) establish any other arrangement
       satisfactory to Fitch, S&P and Moody's which will be sufficient to
       restore the immediately prior ratings of the Certificates. For avoidance
       of doubt, a downgrade of the ratings on the Certificates could occur in
       the event that Party A does not post sufficient collateral. For purposes
       of this Transaction, a "Ratings Event" shall occur with respect to Party
       A (or any applicable credit support provider) if its short term unsecured
       and unsubordinated debt rating is withdrawn or reduced below "F1" by
       Fitch, its short term unsecured and unsubordinated debt rating is
       withdrawn or reduced below "A-1" by S&P, or its short-term unsecured
       unsubordinated debt rating is withdrawn or reduced below "P-1" by Moody's
       (including in connection with a merger, consolidation or other similar
       transaction by Party A or any applicable credit support provider) such
       ratings being referred to herein as the "Approved Rating Thresholds,"
       unless, within thirty (30) days hereafter, each of Fitch and Moody's has
       reconfirmed the ratings of the Certificates, as applicable, which was in
       effect immediately prior thereto (such confirmation a "Rating Agency
       Confirmation").

13     Waiver of Right to Trial by Jury

       EACH PARTY HEREBY IRREVOCABLY WAIVES ANY AND ALL RIGHTS TO TRIAL BY JURY
       WITH RESPECT TO ANY LEGAL PROCEEDING ARISING OUT OF OR RELATING TO THIS
       TRANSACTION.

14     Eligible Contract Participant

       Each party represents to the other party that it is an "eligible contract
       participant" as defined in Section 1a(12) of the U.S. Commodity Exchange
       Act, as amended.

15     Multibranch Party

       For purpose of Section 10(c) of the Form Master Agreement: (a) Party A is
       a Multibranch Party; and (b) Party B is not a Multibranch Party.

16     Other provisions

       (d)    Addresses for notices. As set forth on page 1 hereof.

       (e)    For the purpose of Section 13(c) of the Form Master Agreement: (i)
              Party A appoints as its Process Agent, not applicable; and (ii)
              Party B appoints as its Process Agent, not applicable.

       (f)    Section 12(a)(ii) of the Form Master Agreement is deleted in its
              entirety.

       (g)    Documents to be Delivered. For the purpose of Section 4(a) of the
              Form Master Agreement:

<TABLE>
<CAPTION>
 Party required to      Form/Document/Certificate      Date by which to   Covered by Section
  deliver document                                       be delivered     3(d) Representation
  ----------------      -------------------------        ------------     -------------------
<S>                   <C>                             <C>                 <C>
Party A and Party B   A certificate of an             Upon the            Yes
                      authorized officer of the       execution and
                      party, as to the incumbency     delivery of this
                      and authority of the            Confirmation
                      respective officers of the
                      party signing this
                      Confirmation


Party A               Legal opinion satisfactory in   Upon execution      No
                      form and substance to Party B   and delivery of
                      relating to the enforceability  this Confirmation
                      of Party A's obligations under
                      this Agreement

Party B               The Pooling and Servicing       Within 30 days of   Yes
                      Agreement                       October 30, 2006
</TABLE>

       (h)    Limitation of Liability

              It is expressly understood and agreed by the parties hereto that
              (a) this letter agreement is executed and delivered by Wells Fargo
              Bank, N.A., not individually or personally but solely as the
              Master Servicer on behalf of the Issuing Entity, in the exercise
              of the powers and authority conferred and vested in it, (b) the
              representations, undertakings and agreements herein are made on
              the part of the Issuing Entity and intended not as personal
              representations, undertakings and agreements by the Master
              Servicer but are made and intended for the purpose of binding only
              the Issuing Entity, (c) nothing herein contained shall be
              construed as creating any liability on Wells Fargo Bank, N.A.,
              individually or personally, to perform any covenant either
              expressed or implied contained herein, all such liability, if any,
              being expressly waived by the parties who are signatories to this
              letter agreement and by any person claiming by, through or under
              such parties, and (d) under no circumstances shall Wells Fargo
              Bank, N.A. be personally liable for the payment of any
              indebtedness or expenses of the Issuing Entity or be liable for
              the breach or failure of any obligation, representation, warranty
              or covenant made or undertaken under this letter agreement.

       (i)    This letter agreement may be executed in several counterparts,
              each of which shall be deemed an original but all of which
              together shall constitute one and the same instrument.

       (j)    USA PATRIOT Act Notice. Party A hereby notifies Party B that
              pursuant to the requirements of the USA PATRIOT ACT (Title III of
              Pub. L. 107-56 (signed into law October 26, 2001)), as amended
              (the "Act"), it is required to obtain, verify and record
              information that identifies Party B, which information includes
              the name and address of Party B and other information that will
              allow Party A to identify Party B in accordance with the Act.

       (k)    Proceedings

              Party A shall not institute against or cause any other person to
              institute against, or join any other person in instituting
              against, Party B, any bankruptcy, reorganization, arrangement,
              insolvency or liquidation proceedings, or other proceedings under
              any federal or state bankruptcy, dissolution or similar law, for a
              period of one year and one day following indefeasible payment in
              full of the Certificates, provided that nothing herein shall
              preclude, or be deemed to estop Party A from taking any action in
              any case or proceeding voluntarily filed or commenced by or on
              behalf of Party B or in any involuntary case or proceeding after
              it has been commenced.

       (l)    Set-off

              Notwithstanding any provision of this Agreement (other than 2(c)
              and 6(e)) or any other existing or future agreement, each party
              irrevocably waives any and all rights it may have to set-off, net,
              recoup or otherwise withhold or suspend or condition payment or
              performance of any obligation between it and the other party
              hereunder against any obligation between it and the other party
              under any other agreements.

       (m)    Section 1(c)

              For purposes of Section 1(c) of the Form Master Agreement, this
              Transaction shall be the sole Transaction under the Agreement.

       (n)    Transfer and Amendment

              Subject to Part 13 herein, no transfer, amendment, waiver,
              supplement, assignment or other modification of this Transaction
              shall be permitted by either party unless the Rating Agency
              Condition has been satisfied.

                  [remainder of page intentionally left blank]

<PAGE>

The time of dealing will be confirmed by Barclays upon written request. Barclays
is regulated by the Financial Services Authority. Barclays is acting for its own
account in respect of this Transaction.

Please confirm that the foregoing correctly sets forth all the terms and
conditions of our agreement with respect to the Transaction by responding within
three (3) Business Days by promptly signing in the space provided below and both
(i) faxing the signed copy to Incoming Transaction Documentation, Barclays
Capital Global OTC Transaction Documentation & Management, Global Operations,
Fax +(44) 20-7773-6810/6857, Tel +(44) 20-7773-6901/6904/6965, and (ii) mailing
the signed copy to Barclays Bank PLC, 5 The North Colonnade, Canary Wharf,
London E14 4BB, Attention of Incoming Transaction Documentation, Barclays
Capital Global OTC Transaction Documentation & Management, Global Operation.
Your failure to respond within such period shall not affect the validity or
enforceability of the Transaction against you. This facsimile shall be the only
documentation in respect of the Transaction and accordingly no hard copy
versions of this Confirmation for this Transaction shall be provided unless the
Counterparty requests.

For and on behalf of             For and on behalf of
BARCLAYS BANK PLC                Wells Fargo Bank, N.A., not individually but
                                 solely as master servicer under the Pooling and
                                 Servicing Agreement on behalf of Wells Fargo
                                 Mortgage Backed Securities 2006-16 Trust

/s/ Jason Hatley                 /s/ Jennifer L. Richardson
-----------------------------    -----------------------------
Name: Jason Hatley               Name: Jennifer L. Richardson
Title: Authorized Signatory      Title: Vice President
Date: October 30, 2006           Date: October 30, 2006

Barclays Bank PLC and its Affiliates, including Barclays Capital Inc., may share
with each other information, including non-public credit information, concerning
its clients and prospective clients. If you do not want such information to be
shared, you must write to the Director of Compliance, Barclays Bank PLC, 200
Park Avenue, New York, NY 10166.

<PAGE>

Schedule A to the Confirmation dated as of October 30, 2006
Reference: 1425591B/1425586B

     From and including         To but excluding          Notional Amount (USD):
     ------------------         ----------------          ----------------------

           10/25/2006                 11/25/2006            12,400,000.00
           11/25/2006                 12/25/2006            12,400,000.00
           12/25/2006                  1/25/2007            12,400,000.00
            1/25/2007                  2/25/2007            12,400,000.00
            2/25/2007                  3/25/2007            12,400,000.00
            3/25/2007                  4/25/2007            12,400,000.00
            4/25/2007                  5/25/2007            12,400,000.00
            5/25/2007                  6/25/2007            12,400,000.00
            6/25/2007                  7/25/2007            12,400,000.00
            7/25/2007                  8/25/2007            12,400,000.00
            8/25/2007                  9/25/2007            12,400,000.00
            9/25/2007                 10/25/2007            12,400,000.00
           10/25/2007                 11/25/2007             8,771,410.99
           11/25/2007                 12/25/2007             8,500,801.37
           12/25/2007                  1/25/2008             8,235,194.18
            1/25/2008                  2/25/2008             7,974,529.13
            2/25/2008                  3/25/2008             7,718,747.68
            3/25/2008                  4/25/2008             7,467,792.98
            4/25/2008                  5/25/2008             7,221,609.89
            5/25/2008                  6/25/2008             6,980,144.83
            6/25/2008                  7/25/2008             6,743,345.81
            7/25/2008                  8/25/2008             6,511,444.09
            8/25/2008                  9/25/2008             6,284,661.98
            9/25/2008                 10/25/2008             6,062,924.88
           10/25/2008                 11/25/2008             5,846,159.16
           11/25/2008                 12/25/2008             5,634,292.13
           12/25/2008                  1/25/2009             5,427,252.06
            1/25/2009                  2/25/2009             5,224,968.15
            2/25/2009                  3/25/2009             5,027,370.53
            3/25/2009                  4/25/2009             4,834,390.22
            4/25/2009                  5/25/2009             4,645,959.17
            5/25/2009                  6/25/2009             4,462,010.19
            6/25/2009                  7/25/2009             4,282,476.98
            7/25/2009                  8/25/2009             4,107,294.11
            8/25/2009                  9/25/2009             3,936,397.00
            9/25/2009                 10/25/2009             3,769,721.90
           10/25/2009                 11/25/2009             3,607,205.93
           11/25/2009                 12/25/2009             3,448,787.01
           12/25/2009                  1/25/2010             3,294,403.86
            1/25/2010                  2/25/2010             3,143,996.04
            2/25/2010                  3/25/2010             2,997,503.87
            3/25/2010                  4/25/2010             2,854,868.47
            4/25/2010                  5/25/2010             2,716,031.74
            5/25/2010                  6/25/2010             2,580,936.32
            6/25/2010                  7/25/2010             2,449,525.63
            7/25/2010                  8/25/2010             2,321,743.82
            8/25/2010                  9/25/2010             2,197,535.77
            9/25/2010                 10/25/2010             2,076,847.12
           10/25/2010                 11/25/2010             1,959,624.18
           11/25/2010                 12/25/2010             1,845,813.99
           12/25/2010                  1/25/2011             1,735,364.31
            1/25/2011                  2/25/2011             1,628,223.57
            2/25/2011                  3/25/2011             1,524,340.87
            3/25/2011                  4/25/2011             1,423,666.00
            4/25/2011                  5/25/2011             1,326,149.42
            5/25/2011                  6/25/2011             1,231,742.23
            6/25/2011                  7/25/2011             1,140,396.20
            7/25/2011                  8/25/2011             1,052,063.71
            8/25/2011                  9/25/2011              966,697.81
            9/25/2011                 10/25/2011              884,252.14
           10/25/2011                 11/25/2011              804,680.98
           11/25/2011                 12/25/2011              730,816.67
           12/25/2011                  1/25/2012              659,712.70
            1/25/2012                  2/25/2012              591,937.27
            2/25/2012                  3/25/2012              528,220.81
            3/25/2012                  4/25/2012              468,478.61
            4/25/2012                  5/25/2012              412,627.48
            5/25/2012                  6/25/2012              360,585.69
            6/25/2012                  7/25/2012              312,272.99
            7/25/2012                  8/25/2012              267,610.54
            8/25/2012                  9/25/2012              226,520.94
            9/25/2012                 10/25/2012              188,928.13
           10/25/2012                 11/25/2012              154,757.45
           11/25/2012                 12/25/2012              125,359.06
           12/25/2012                  1/25/2013              99,210.50
            1/25/2013                  2/25/2013              76,241.31
            2/25/2013                  3/25/2013              56,382.32
            3/25/2013                  4/25/2013              39,565.58
            4/25/2013                  5/25/2013              25,724.41
            5/25/2013                  6/25/2013              14,793.27
            6/25/2013                  7/25/2013               6,707.86
            7/25/2013                  8/25/2013               1,405.01

<PAGE>

                                     ISDA(R)

              International Swaps and Derivatives Association, Inc.

                              CREDIT SUPPORT ANNEX

                                     to the

                    ISDA Master Agreement deemed entered into

                          dated as of October 30, 2006

                                     between


       BARCLAYS BANK PLC                  WELLS FARGO BANK, N.A., not
                                          individually but solely as master
                                          servicer under the Pooling and
                                          Servicing Agreement on behalf of Wells
                                          Fargo Mortgage Backed Securities
                                          2006-16 Trust

.................................   and  ........................................
         ("Party A")                                ("Party B")

This Annex supplements, forms part of, and is subject to, the above-referenced
Agreement, is part of its Schedule and is a Credit Support Document under this
Agreement with respect to each party.

Paragraph 13.

(a)     Security Interest for "Obligations". The term "Obligations" as used in
        this Annex includes the following additional obligations:

                With respect to Party A: None.

                With respect to Party B: None.

(b)     Credit Support Obligations.

        (i)     Delivery Amount, Return Amount and Credit Support Amount.

                (A)     "Delivery Amount" has the meaning specified in Paragraph
                        3(a) , except that the words "upon a demand made by the
                        Secured Party on or promptly following a Valuation Date"
                        shall be deleted and replaced with the words "not later
                        than the close of business on the next Local Business
                        Day following a Valuation Date"; and

                (B)     "Return Amount" has the meaning specified in Paragraph
                        3(b).

                (C)     "Credit Support Amount". shall not have the meaning
                        specified in Paragraph 3(b) and, instead, will have the
                        following meaning:

                        "Credit Support Amount" means, (a) for any Valuation
                        Date on which a Ratings Event (as defined in the
                        Agreement) has occurred and is continuing and Party A
                        has not otherwise complied with Section 12 of this
                        Agreement, the Secured Party's Modified Exposure for
                        that Valuation Date.

        (ii)    Eligible Credit Support. On any date, the following items will
                qualify as "Eligible Credit Support" for each party:

<TABLE>
<CAPTION>
                                                                               Valuation
                                                                               Percentage
                                                                               ----------
<S>     <C>                                                                    <C>
(A)     cash in U.S Dollars                                                    100%

(B)     negotiable debt obligations issued after 18 July 1984 by the U.S.      98.0%
        Treasury Department having a residual maturity on such
        date of less than 1 year (with local and foreign currency
        issuer ratings of Moody's Aa2 and S&P AA or above)

(C)     negotiable debt obligations issued after 18 July 1984 by               To be agreed
        the U.S. Treasury Department having a                                  between Party A
        residual maturity on such date equal to or                             and Party B with
        greater than 1 year but less than 5 years                              the approval of
        (with local and foreign currency issuer                                the Rating
        ratings of Moody's Aa2 and S&P AA or above)                            Agencies

(D)     negotiable debt obligations issued after l8 July 1984 by               To be agreed
        the U.S. Treasury Department having a                                  between Party A
        residual maturity on such date equal to or                             and Party B with
        greater than 5 years but less than 10                                  the approval of
        years (with local and foreign currency                                 the Rating
        issuer ratings of Moody's Aa2 and S&P AA or above)                     Agencies

(E)     negotiable debt obligations of the Government National Mortgage        To be agreed
        Association, the Federal National Mortgage                             between Party A
        Association, the Federal Home Loan Mortgage                            and Party B with
        Corporation, the Student Loan Marketing Association                    the approval of
        or a Federal Home Loan Bank (all entities rated                        the Rating
        Moody's Aal and S&P AA+ or above) with a residual                      Agencies
        maturity on such date equal to or greater than 1
        year but less than 3 years.

(F)     negotiable debt obligations of the Government National Mortgage        To be agreed
        Association, the Federal National Mortgage                             between Party A
        Association, the Federal Home Loan Mortgage                            and Party B with
        Corporation, the Student Loan Marketing Association                    the approval of
        or a Federal Home Loan Bank (all entries rated                         the Rating
        Moody's Aa 1 and S&P AA+ or above) with a residual                     Agencies
        maturity on such date equal to or greater than 3
        years but less than 5 years.

(G)     negotiable debt obligations of the Government National Mortgage        To be agreed
        Association, the Federal National Mortgage                             between Party A
        Association, the Federal Home Loan Mortgage                            and Party B with
        Corporation, the Student Loan Marketing Association                    the approval of
        or a Federal Home Loan Bank (all entries rated                         the Rating
        Moody's Aal and S&P AA+ or above) with a residual                      Agencies
        maturity on such date equal to or greater than 5
        years but less than 7 years.

(H)     negotiable debt obligations of the Government National Mortgage        To be agreed
        Association, the Federal National Mortgage                             between Party A
        Association, the Federal Home Loan Mortgage                            and Party B with
        Corporation, the Student Loan Marketing Association                    the approval of
        or a Federal Home Loan Bank (all entries rated                         the Rating
        Moody's Aal and S&P AA+ or above) with a residual                      Agencies
        maturity on such date equal to or greater than 7
        years but less than 10 years.
</TABLE>

        For the avoidance of doubt, where negotiable debt obligations are rated
        by only one of the above relevant rating agencies, the rating applied
        will be based on the rating of that agency. Notwithstanding the
        foregoing, the Eligible Collateral referenced above may only be posted
        if S&P has assigned a rating to such Eligible Collateral.

        Where the ratings of the relevant agencies differ with respect to the
        same negotiable debt obligation, the lower of the ratings shall apply.

        In addition, upon a Ratings Event, Party A shall agree the Valuation
        Percentage in relation to (C) through (H) above with the relevant rating
        agency, which shall be S&P, Moody's and Fitch (to the extent such
        ratings agency has provided a rating for the underlying Certificates);
        provided, however, that if Party A is required to post collateral in
        accordance with the terms of this Agreement it shall post only (A) and
        (B) above until such time as the Valuation Percentages are agreed.

        (iii)   Other Eligible Support. Such Other Eligible Support as the
                Pledgor may designate; provided, at the expense of the Pledgor,
                the prior written consent of the relevant rating agency, which
                shall be S&P, Moody's and Fitch (to the extent such ratings
                agency has provided a rating for the underlying Certificates)),
                shall have been obtained. For the avoidance of doubt there are
                no items which qualify as Other Eligible Support as of the date
                of this Annex.

        (iv)    Thresholds.

                (A)     "Independent Amount" means zero.

                (B)     "Threshold" means for Party A:

                        1.      infinity, unless (i) a Ratings Event occurs and
                                is continuing and (ii) Party A has not otherwise
                                complied with Section 12 of this Agreement, then
                                its Threshold shall be zero, or

                        2.      in the event that Party A has otherwise complied
                                with Section 12 of this Agreement, its Threshold
                                shall continue to be infinity.

                        "Threshold" means, for Party B: infinity

                (C)     "Minimum Transfer Amount" means USD 100,000, provided,
                        however, with respect to the Secured Party at any time
                        when the Secured Party is a Defaulting Party, "Minimum
                        Transfer Amount" means zero.

                (D)     Rounding: The Delivery Amount and the Return Amount will
                        not be rounded.

(c)     Valuation and Timing.

        (i)     "Valuation Agent" means Party A. The valuation agent's
                calculations shall be made in accordance with market practices
                using commonly accepted third party sources such as Bloomberg or
                Reuters.

        (ii)    "Valuation Date" means each Local Business Day which, if treated
                as a Valuation Date, would result in a Delivery Amount or Return
                Amount.

        (iii)   "Valuation Time" means the close of business in the city of the
                Valuation Agent on the Local Business Day before the Valuation
                Date or date of calculation, as applicable, provided that the
                calculations of Value and Exposure will be made as of
                approximately the same time on the same date.

        (iv)    "Notification Time" means 11:00 a.m., New York time, on a Local
                Business Day.

(d)     Conditions Precedent and Secured Party's Rights and Remedies. The
        following Termination Event will be a "Specified Condition" for the
        party specified (that party being the Affected Party if the Termination
        Event occurs with respect to that party): None.

(e)     Substitution.

        (i)     "Substitution Date" has the meaning specified in Paragraph
                4(d)(ii).

        (ii)    Consent. The Pledgor is not required to obtain the Secured
                Party's consent for any substitution purusant to Paragraph 4(d).

(f)     Dispute Resolution.

        (i)     "Resolution Time" means 1:00 p.m. New York time on the Local
                Business Day following the date on which the notice of the
                dispute is given under Paragraph 5.

                Value. For the purpose of Paragraphs 5(i)(C) and 5(ii), on any
                date, the Value of Eligible Credit Support will be calculated as
                follows:

                For Eligible Credit Support comprised of cash, the amount of
                such cash.

                For Eligible Collateral comprising securities; the sum of (a)(x)
                the last bid price on such date for such securities on the
                principal national securities exchange on which such securities
                are listed, multiplied by the applicable Valuation Percentage or
                (y) where any such securities are not listed on a national
                securities exchange, the bid price for such securities quoted as
                at the close of business on such date by any principal market
                maker for such securities chosen by the Valuation Agent,
                multiplied by the applicable Valuation Percentage or (z) if no
                such bid price is listed or quoted for such date, the last bid
                price listed or quoted (as the case may be), as of the day next
                preceding such date on which such prices were available;
                multiplied by the applicable Valuation Percentage; plus (b) the
                accrued interest on such securities (except to the extent that
                such interest shall have been paid to the Pledgor pursuant to
                Paragraph 6(d)(ii) or included in the applicable price referred
                to in subparagraph (a) above) as of such date.

        (ii)    Alternative. The provisions of Paragraph 5 will apply; provided
                that the obligation of the appropriate party to deliver the
                undisputed amount to the other party will not arise prior to the
                time that would otherwise have applied to the Transfer pursuant
                to, or deemed made, under Paragraph 3 if no dispute had arisen.

(g)     Holding and Using Posted Collateral.

        (i)     Eligibility to Hold Posted Collateral; Custodians.

                Party B is not and will not be entitled to hold Posted
                Collateral. Party B's Custodian will be entitled to hold Posted
                Collateral pursuant to Paragraph 6(b); provided that the
                Custodian for Party B shall be the same banking institution that
                acts as Master Servicer for the Certificates (as defined in the
                Pooling and Servicing Agreement) for Party B.

                Initially, the Custodian for Party B is : Wells Fargo Bank, N.A.

        (ii)    Use of Posted Collateral. The provisions of Paragraph 6(c) will
                not apply to Party B; therefore, Party B will not have any of
                the rights specified in Paragraph 6(c)(i) or 6 (c)(ii);
                provided, however, that the Trustee shall invest Cash Posted
                Credit Support in such investments as designated by Party A,
                with losses (net of gains) incurred in respect of such
                investments to be for the account of Party A.

(h)     Distributions and Interest Amount.

        (i)     Interest Rate. The "Interest Rate" will be the rate earned on
                Cash Posted Credit Support pursuant to clause (g)(ii) above.

        (ii)    Transfer of Interest Amount. The Transfer of the Interest Amount
                will be made on each Distribution Date.

        (iii)   Alternative to Interest Amount. The provisions of Paragraph
                6(d)(ii) will not apply.

(i)     Additional Representation(s).

                There are no additional representations by either party.

(j)     Other Eligible Support and Other Posted Support.

        (i)     "Value" with respect to Other Eligible Support and Other Posted
                Support shall have such meaning as the parties shall agree in
                writing from time to time.

        (ii)    "Transfer" with respect to Other Eligible Support and Other
                Posted Support shall have such meaning as the parties shall
                agree in writing from time to time.

(k)     Demands and Notices.

        All demands, specifications and notices under this Annex will be made
        pursuant to the Notices Section of this Agreement, save that any demand,
        specification or notice:

        (i)     shall be given to or made at the following addresses:

        If to Party A:

                    5 The North Colonnade
                    Canary Wharf
                    London E14 4BB, England
                    Attention: Swaps Documentation
                    Facsimile No.: 0207-773-6857/6858
                    Telephone No.: 0207-773-6915/6904

        with a copy to:

                    General Counsel's Office
                    200 Park Avenue
                    New York, N.Y. 10166

        Notices to Party A shall not be deemed effective unless delivered to the
        London address set forth above.

        If to Party B:

               Wells Fargo Bank, N.A.
               9062 Old Annapolis Road
               Columbia, Maryland 21045
               Attn: Client Manager - WFMBS 2006-16
               Facsimile: 410-715-2380
               Telephone: 410-884-2000

        or at such other address as the relevant party may from time to time
        designate by giving notice (in accordance with the terms of this
        paragraph) to the other party;

        (ii)    shall (unless otherwise stated in this Annex) be deemed to be
                effective at the time such notice is actually received unless
                such notice is received on a day which is not a Local Business
                Day or after the Notification Time on any Local Business Day in
                which event such notice shall be deemed to be effective on the
                next succeeding Local Business Day.

(l)     Address for Transfers.

        Party B: To be notified by Party B to Party A at the time of the request
        for Transfer.

(m)     Other Provisions.

        (i)     Additional Definitions. As used in this Annex:

                "Local Business Day" means: (i) any day on which commercial
                banks are open for business (including dealings in foreign
                exchange and foreign currency deposits) in London, New York and
                the location of the Trustee, and (ii) in relation to a Transfer
                of Eligible Credit Support, a day on which the clearance system
                agreed between the parties for the delivery of Eligible Credit
                Support is open for acceptance and execution of settlement
                instructions (or in the case of a Transfer of Cash or other
                Eligible Credit Support for which delivery is contemplated by
                other means, a day on which commercial banks are open for
                business (including dealings for foreign exchange and foreign
                deposits) in New York and such other places as the parties shall
                agree).

        (ii)    Holding Collateral. The Secured Party shall cause any Custodian
                appointed hereunder to open and maintain a segregated account
                and to hold, record and identify all the Posted Collateral in
                such segregated account and, subject to Paragraph 8(a), such
                Posted Collateral shall at all times be and remain the property
                of the Pledgor and shall at no time constitute the property of,
                or be commingled with the property of, the Secured Party or the
                Custodian.

        (iii)   Agreement as to Single Secured Party and Pledgor. Party A and
                Party B agree that, notwithstanding anything to the contrary in
                this Annex, (a) the term "Secured Party" as used in this Annex
                means only Party B, (b) the term "Pledgor" as used in this Annex
                means only Party A, (c) only Party A makes the pledge and grant
                in Paragraph 2, the acknowledgement in the final sentence of
                Paragraph 8(a) and the representations in Paragraph 9 and (d)
                Party A shall have no obligations under this Annex other than
                during a Collateral Requirement Period.

        (iv)    Form of Annex. The parties hereby agree that the text of the
                body of this Annex is intended to be the printed form of ISDA
                Credit Support Annex (Bilateral Form - ISDA Agreements Subject
                to New York Law version) as published and copyrighted by the
                International Swaps and Derivatives Association, Inc.

        (v)     Exposure. The Parties agree that in the event of a Ratings Event
                relating to an action taken by S&P, the Valuation Agent shall
                internally verify its calculation of the Secured Party's
                Exposure by reporting its calculation thereof to S&P on a weekly
                basis. In addition, in the case where the long term
                unubordinated and unsecured debt of Party A ceases to be rated
                at least BBB+ by S&P, the Valuation Agent shall externally
                verify its calculation of the Secured Party's Exposure by
                seeking two quotations from Reference Market-makers at the end
                of each month (such quotations being for amounts payable as
                described in the definition of "Market Quotations" in the
                Agreement where the date on which such quotations are sought is
                the Early Termination Date and the Transaction entered into
                pursuant to the Agreement is the only Termination Transaction).
                In the case where external verification of the Exposure
                calculation is required, the Valuation Agent must (i) obtain at
                least two such quotations (ii) may not obtain the quotations
                referred to above from the same Reference Market-maker in excess
                of four times during any 12 month period. Furthermore, the
                Exposure valuations should reflect the higher of two bids from
                Reference Market-makers that would be eligible and willing to
                provide the market quotation in the absence of the current
                provider and (iii) must submit to S&P the two bids provided by
                external parties. The collateral requirement should be based on
                the greater of the internal and external verifications. In the
                event the verification procedures set forth above indicate that
                there is a deficiency in the amount of Eligible Collateral that
                has been posted to the Secured Party, the Pledgor shall post the
                amount of Eligible Collateral necessary to cure such deficiency
                to the Secured Party within three Local Business Days.

        (vi)    Expenses. Notwithstanding Paragraph 10, the Pledgor will be
                responsible for, and will reimburse the Secured Party for, all
                transfer and other taxes and other costs involved in the
                transfer of Eligible Collateral.

        (vii)   Additional Definitions. As used in this Annex:

                "Ratings Event" means a "Ratings Event" (as defined in the
                Agreement).

                "Modified Exposure" means, for any Valuation Date, an amount
                equal to the greater of (a) the sum of Secured Party's Exposure
                for that Valuation Date plus the Notional Volatility Buffer and
                (b) zero.

                "Notional Volatility Buffer" as determined by the Valuation
                Agent for any date, means the outstanding Notional Amount of the
                Transaction on such date multiplied by the relevant percentage
                for such date as set out in the table below on such date.

                                  Less than or
                                  equal to 5      Less than or equal to
                                  years to        10 years but greater
                                  Termination     than 5 years to
        Party A S&P Rating on     Date of the     Termination Date of
        such date                 Transaction     the Transaction
        ---------------------     ------------    ---------------------

        Short Term Rating of A-2  3.25%           4.00%

        Short Term Rating of A-3  4.00%           5.00%

        Long Term Rating of BB+   4.50%           5.75%
        or lower

<PAGE>

        IN WITNESS WHEREOF, the parties have executed this Annex by their duly
authorized representatives as of the date of the Agreement.

     BARCLAYS BANK PLC                  WELLS FARGO BANK, N.A., not individually
                                        but solely as master servicer under the
                                        Pooling and Servicing Agreement on
                                        behalf of Wells Fargo Mortgage Backed
                                        Securities 2006-16 Trust

By:  /s/ LeeLee Panno                   By: /s/ Jennifer L. Richardson
     -----------------------------          -----------------------------
     Name: LeeLee Panno                     Name: Jennifer L. Richardson
     Title: Assoc. Director                 Title: Vice President
     Date: October 27, 2006                 Date: October 30, 2006