UNITED STATES
                     SECURITIES AND EXCHANGE COMMISSION
                            WASHINGTON, D.C. 20549

                                  FORM 10-K


  (Mark one)

  /X/ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES
      EXCHANGE ACT OF 1934
      For the fiscal year ended December 31, 2007

      OR


  / / TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES
      EXCHANGE ACT OF 1934
      For the transition period from ____________ to ____________



      Commission file number: 333-140279-11

      Thornburg Mortgage Securities Trust 2007-4
      (exact name of issuing entity as specified in its charter)

      Greenwich Capital Acceptance, Inc. (depositor)
      (exact name of the registrant as specified in its charter)

      Thornburg Mortgage Home Loans, Inc.
      (exact name of the sponsor as specified in its charter)



  Delaware                                06-1199884
  (State or other jurisdiction of         (I.R.S. Employer
  incorporation or organization)          Identification No.)



  600 Steamboat Road
   Greenwich, CT                                06830
  (Address of principal executive             (Zip Code)
  offices)


 Registrant's telephone number, including area code: (203) 625-2700



  Securities registered pursuant to Section 12(b) of the Act:

    NONE.



  Securities registered pursuant to Section 12(g) of the Act:

    NONE.



  Indicate by check mark if the registrant is a well-known seasoned issuer, as
  defined in Rule 405 of the Securities Act.

    Yes ___     No  X



  Indicate by check mark if the registrant is not required to file reports
  pursuant to Section 13 or Section 15(d) of the Act.

    Yes ___     No  X




  Indicate by check mark 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.

    Yes  X      No ___



  Indicate by check mark if disclosure of delinquent filers pursuant to Item
  405 of Regulation S-K (Section 229.405 of this chapter) is not contained
  herein, and will not be contained, to the best of registrant's knowledge, in
  definitive proxy or information statements incorporated by reference in Part
  III of this Form 10-K or any amendment to this Form 10-K.

           X



  Indicate by check mark whether the registrant is a large accelerated filer,
  an accelerated filer, a non-accelerated filer, or a smaller reporting
  company.  See the definitions of "large accelerated filer", "accelerated
  filer" and "smaller reporting company" in Rule 12b-2 of the Exchange Act.

   Large accelerated filer ___
   Accelerated filer ___
   Non-accelerated filer      X
   Smaller reporting company ___

  Indicate by check mark whether the registrant is a shell company (as defined
  in Rule 12b-2 of the Act).

    Yes ___     No  X



  State the aggregate market value of the voting and non-voting common equity
  held by non-affiliates computed by reference to the price at which the
  common equity was last sold, or the average bid and asked price of such
  common equity, as of the last business day of the registrant's most recently
  completed second fiscal quarter.

    Not applicable.



  Indicate by check mark whether the registrant has filed all documents and
  reports required to be filed by Section 12, 13 or 15(d) of the Securities
  Exchange Act of 1934 subsequent to the distribution of securities under a
  plan confirmed by a court.

    Not applicable.



  Indicate the number of shares outstanding of each of the registrant's
  classes of common stock, as of the latest practicable date.

    Not applicable.



  DOCUMENTS INCORPORATED BY REFERENCE

  List hereunder the following documents if incorporated by reference and the
  Part of the Form 10-K (e.g., Part I, Part II, etc.) into which the document
  is incorporated: (1)Any annual report to security holders; (2) Any proxy or
  information statement; and (3)Any prospectus filed pursuant to Rule 424(b)
  or (c) under the Securities Act of 1933. The listed documents should be
  clearly described for identification purposes (e.g., annual report to
  security holders for fiscal year ended December 24, 1980).

    Not applicable.





                                     PART I

  Item 1.      Business.

               Not applicable.


  Item 1A.     Risk Factors.

               Not applicable.


  Item 1B.     Unresolved Staff Comments.

               None.


  Item 2.      Properties.

               Not applicable.


  Item 3.      Legal Proceedings.

               None.


  Item 4.      Submission of Matters to a Vote of Security Holders.

               Not applicable.




                                     PART II

  Item 5.      Market for Registrant's Common Equity, Related Stockholder
               Matters and Issuer Purchases of Equity Securities.

               Not applicable.


  Item 6.      Selected Financial Data.

               Not applicable.


  Item 7.      Management's Discussion and Analysis of Financial Condition and
               Results of Operation.

               Not applicable.


  Item 7A.     Quantitative and Qualitative Disclosures About Market Risk.

               Not applicable.


  Item 8.      Financial Statements and Supplementary Data.

               Not applicable.


  Item 9.      Changes in and Disagreements With Accountants on Accounting and
               Financial Disclosure.

               Not applicable.


  Item 9A.     Controls and Procedures.

               Not applicable.


  Item 9A(T).  Controls and Procedures.

               Not applicable.


  Item 9B.     Other Information.

               None.




                                    PART III

  Item 10.     Directors, Executive Officers and Corporate Governance.

               Not applicable.


  Item 11.     Executive Compensation.

               Not applicable.


  Item 12.     Security Ownership of Certain Beneficial Owners and Management
               and Related Stockholder Matters.

               Not applicable.


  Item 13.     Certain Relationships and Related Transactions, and Director
               Independence.

               Not applicable.


  Item 14.     Principal Accounting Fees and Services.

               Not applicable.




  ADDITIONAL DISCLOSURE ITEMS PURSUANT TO GENERAL INSTRUCTION J


Item 1112(b) of Regulation AB, Significant Obligor Financial Information.

No single obligor represents 10% or more of the pool assets held by the issuing
entity.



Item 1114(b)(2) of Regulation AB, Significant Enhancement  Provider Financial
Information.

No entity or group of affiliated entities provides any external credit
enhancement or other support for the certificates within this transaction as
described under Item 1114 (a) of Regulation AB.



Item 1115(b) of Regulation AB, Certain Derivatives Instruments (Financial
Information).

No entity or group of affiliated entities provides any derivative instruments or
other support for the certificates within this transaction as described under
Item 1115 of Regulation AB.



Item 1117 of Regulation AB, Legal Proceedings.

The information regarding this Item has been previously filed in a 424(b)(5)
filing dated August 31, 2007.



Item 1119 of Regulation AB, Affiliations and Certain Relationships and Related
Transactions.

Information required by item 1119 has been omitted from this annual
report on Form 10-K because it is materially the same information as has been
provided previously in a prospectus timely filed pursuant to Rule 424
promulgated under the Securities Act of 1933 under the same Central Index Key
(CIK) code as this annual report on Form 10-K.



Item 1122 of Regulation AB, Compliance with Applicable Servicing Criteria.

The reports on assessment of compliance with the servicing criteria for
asset-backed securities are attached hereto under Item 15.

               LaSalle Bank National Association's ("LaSalle") Report on
          Assessment of Compliance with Servicing Criteria for 2007 (the
          "2007 Assessment") attached to this Report on Form 10-K describes
          in Appendix B the following material instance of noncompliance
          related to investor reporting:

               "1122(d)(3)(i)(A) and (B) - During the Reporting Period, certain
          monthly investor or remittance reports were not prepared in
          accordance with the terms set forth in the transaction agreements
          and certain investor reports did not provide the information
          calculated in accordance with the terms specified in the
          transaction agreements for which certain individual errors may or
          may not have been material."

               The investor reporting errors identified on LaSalle's 2007
          Assessment as material instances of noncompliance (the "Investor
          Reporting Errors") included, for example, revised delinquency, REO,
          foreclosure, repurchase, payoff or modified loan counts, category
          indicators and/or balances. The conclusion that the Investor
          Reporting Errors amounted to a material instance of noncompliance
          was based primarily on the aggregate number of errors as opposed to
          the materiality of any one error.

             The Investor Reporting Errors were generally caused by human
          error resulting primarily from high volume monthly data processing
          demands that had to be addressed within constricted time frames
          with less than a full complement of operational staff. Between the
          fourth quarter of the Reporting Period and the date of the 2007
          Assessment, LaSalle has employed additional operational staff to
          accommodate the high volume of monthly investor reporting
          requirements and minimize the risk of the Investor Reporting Errors
          recurring. Other necessary controls are in place to minimize the
          risk of such errors.

               With respect to the specific pool assets and asset-backed
          securities related to the Investor Reporting Errors, the errors did
          not have, and are not reasonable likely in the future to have, any
          material impact or effect on pool asset performance, servicing of
          the pool assets and payments or expected payments on the
          mortgage-backed securities.



Item 1123 of Regulation AB, Servicer Compliance Statement.

The servicer compliance statements are attached hereto under Item 15.



                               Part IV

  Item 15. Exhibits, Financial Statement Schedules.

  (a) Exhibits.

  (4.1) Pooling and Servicing Agreement, dated as of August 1, 2007, among
  Greenwich Capital Acceptance, Inc., as Depositor, LaSalle Bank National
  Association, as Trustee and Custodian, Thornburg Mortgage Home Loans, Inc.,
  as Seller and Wells Fargo Bank, N.A., as Master Servicer and Securities
  Administrator, originally filed on Form 8K on September 14, 2007, Commission
  File Number 333-140279-11, CIK Number 0001409686.

  (10.1) Incorporated by reference as Exhibit (4.1).

  (31) Rule 13a-14(d)/15d-14(d) Certification.

  (33) Reports on assessment of compliance with servicing criteria for
  asset-backed securities.


    <TABLE>
    
      <c>

    33.1 Cenlar, FSB as Sub-Servicer for Thornburg Mortgage Home Loans Inc.
    33.2 LaSalle Bank, National Association as Trustee and as Custodian
    33.3 Wells Fargo Bank, N.A. as Master Servicer and Securities Administrator

    </TABLE>


  (34) Attestation reports on assessment of compliance with servicing criteria
  for asset-backed securities.


    <TABLE>
    
      <c>

    34.1 Cenlar, FSB as Sub-Servicer for Thornburg Mortgage Home Loans Inc.
    34.2 LaSalle Bank, National Association as Trustee and as Custodian
    34.3 Wells Fargo Bank, N.A. as Master Servicer and Securities Administrator

    </TABLE>


   (35) Servicer compliance statement.


    <TABLE>
    
       <c>

    35.1 Cenlar, FSB as Sub-Servicer for Thornburg Mortgage Home Loans Inc.
    35.2 Thornburg Mortgage Home Loans Inc. as Servicer
    35.3 Wells Fargo Bank, N.A. as Master Servicer and Securities Administrator

    </TABLE>


   (b) Exhibits identified in paragraph (a) above.

   (c) Not applicable.



                          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.


   Thornburg Mortgage Securities Trust 2007-4
   (Issuing Entity)

   Wells Fargo Bank, N.A.
   (Master Servicer)

   /s/ Kristen Ann Cronin
   Kristen Ann Cronin, Vice President
   (Senior Officer in charge of the servicing function of Wells Fargo Bank,
    N.A., in its capacity as Master Servicer)


    Date:   March 27, 2008



  Exhibit Index

  Exhibit No.


   (4.1) Pooling and Servicing Agreement, dated as of August 1, 2007, among
   Greenwich Capital Acceptance, Inc., as Depositor, LaSalle Bank National
   Association, as Trustee and Custodian, Thornburg Mortgage Home Loans, Inc.,
   as Seller and Wells Fargo Bank, N.A., as Master Servicer and Securities
   Administrator, originally filed on Form 8K on September 14, 2007,
   Commission File Number 333-140279-11, CIK Number 0001409686.

   (10.1) Incorporated by reference as Exhibit (4.1).

   (31) Rule 13a-14(d)/15d-14(d) Certification.

   (33) Reports on assessment of compliance with servicing criteria for
   asset-backed securities.


    <TABLE>

    
      <c>
    33.1 Cenlar, FSB as Sub-Servicer for Thornburg Mortgage Home Loans Inc.
    33.2 LaSalle Bank, National Association as Trustee and as Custodian
    33.3 Wells Fargo Bank, N.A. as Master Servicer and Securities Administrator

    </TABLE>

   (34) Attestation reports on assessment of compliance with servicing
   criteria for asset-backed securities.


    <TABLE>

    
      <c>
    34.1 Cenlar, FSB as Sub-Servicer for Thornburg Mortgage Home Loans Inc.
    34.2 LaSalle Bank, National Association as Trustee and as Custodian
    34.3 Wells Fargo Bank, N.A. as Master Servicer and Securities Administrator

    </TABLE>

   (35) Servicer compliance statement.


    <TABLE>

    
       <c>
    35.1 Cenlar, FSB as Sub-Servicer for Thornburg Mortgage Home Loans Inc.
    35.2 Thornburg Mortgage Home Loans Inc. as Servicer
    35.3 Wells Fargo Bank, N.A. as Master Servicer and Securities Administrator

    </TABLE>