<PAGE>


                                  FORM 10-K

                     SECURITIES AND EXCHANGE COMMISSION

                        WASHINGTON, D.C.  20549-1004

(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, 1996

                                     OR

[ ]  TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES
     EXCHANGE ACT OF 1934


For the transition period from September 1, 1996 to December 31, 1996

Commission file number   333-53115

                    CS First Boston Mortgage Securities Corp.

            (AS DEPOSITOR UNDER THE POOLING AND SERVICING AGREEMENT,
          DATED AS OF SEPTEMBER 1, 1996, PROVIDING FOR THE ISSUANCE OF
                    ASSOCIATES MANUFACTURED HOUSING CONTRACT
                   PASS-THROUGH CERTIFICATES, SERIES 1996-1)

       -----------------------------------------------------------------
             (Exact name of registrant as specified in its charter)

<TABLE>
<S>                            <C>                       <C>
         Delaware                 333-53115                 13-3320910
      ----------------         ---------------            ---------------
      (State or Other           (Commission                (IRS Employer
      jurisdiction of            File Number)            Identification No.)
      incorporation)
</TABLE>

     CS First Boston Mortgage Securities Corp.
     11 Madison Avenue
     New York, New York                                                 10010
     (Address of principal executive offices)                         (Zip Code)

------------------------------------------------------------

Registrant's telephone number, including area code:             (212) 325-2000

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 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 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
                                           -----         -----
Trust does not have any voting stock.

Trust has not been involved in bankruptcy proceedings during the preceding five
years.

Trust is not reporting as a corporate issuer.


<PAGE>


                                     PART I

Item 1.   Business.

          Not Applicable.

Item 2.   Properties.

          The Associates Manufactured Housing Contract Pass-Through
          Certificates, Series 1996-1 (the "Certificates") were issued pursuant
          to a pooling and servicing agreement, dated as of September 1, 1996
          (the "Agreement"), among CS First Boston Mortgage Securities Corp., as
          depositor (the "Depositor"), Ford Consumer Finance Company, Inc. as
          seller and servicer, and The Chase Manhattan Bank, as trustee (the
          "Trustee").

          The Certificates consist of five classes (each, a "Class") of Senior
          Certificates (respectively, the "Class A-1 Certificates," the "Class
          A-2 Certificates," the "Class A-3 Certificates," the "Class A-4
          Certificates" and the "Class A-5 Certificates," and collectively, the
          "Class A Certificates" or the "Senior Certificates") and four Classes
          of subordinate Certificates (respectively, the "Class M Certificates,"
          the "Class B-1 Certificates," the "Class B-2 Certificates" and the
          "Class R Certificates," and collectively, the "Subordinate
          Certificates"). The Certificates were issued in the amounts (with
          respect to each Class, the "Initial Certificate Principal Balance")
          and bear the pass-through rates (with respect to each Class, the
          "Pass-Through Rate") set forth below:

<TABLE>
<CAPTION>
                                        Initial Certificate     Pass-Through
         Class                           Principal Balance          Rate
         -----                          -------------------     ------------
<S>                                     <C>                     <C>
         Class A-1 Certificates            $215,000,000            6.20%
         Class A-2 Certificates            $147,000,000            6.70%
         Class A-3 Certificates            $137,000,000            7.00%
         Class A-4 Certificates            $ 72,000,000            7.30%
         Class A-5 Certificates            $183,573,000            7.60%
         Class M Certificates              $ 64,414,000            7.90%
         Class B-1 Certificates            $ 69,015,000            8.00%
         Class B-2 Certificates            $ 32,209,764            9.00%
</TABLE>



<PAGE>


         Class R Certificates

         The Associates Manufactured Housing Contract Pass-Through Certificates,
         Series 1996-1 (the "Certificates") represent beneficial interests in a
         trust (the "Trust"), the assets of which consist primarily of
         manufactured housing installment sales contracts and installment loan
         agreements (the "Contracts") originated or purchased by Ford Consumer
         Finance Company, Inc. ("FCFC") in the ordinary course of its business
         and conveyed by FCFC to CS First Boston Mortgage Securities Corp. (the
         "Depositor") and then conveyed by the Depositor to the Trust. Payments
         of principal and interest on the Certificates are distributed to
         Certificateholders on the fifteenth day of each month (or if such day
         is not a Business Day, the immediately succeeding Business Day). The
         rights to receive distributions of interest and principal by the
         holders of (i) the Class M Certificates are subordinated to such rights
         of the Senior Certificateholders, (ii) the Class B Certificates are
         subordinated to such rights of the Class A and Class M
         Certificateholders and (iii) the Class B-2 Certificateholders are
         subordinated to such rights of the Class A, Class M and Class B-1
         Certificateholders.

         As of September 1, 1996, the Contract Pool consisted of 32,582
         contracts having an aggregate principal balance of $920,211,764.40.


<PAGE>


          As of December 31, 1996, the end of the year of the Trust for which
          this Form 10-K Annual Report is being filed, there were 31,644
          contracts with an aggregate value of $887,553,664.57 outstanding.

       The change in the aggregate principal balance of the Contracts between
       September 1, 1996, and December 31, 1996, was due to: (i) scheduled
       principal payments, made by or on behalf of the Obligors on the
       Contracts; and (ii) payment in full of 760 Contracts. There were no
       repurchases of defaulted Contracts pursuant to the Reserve Fund. The net
       loss on Contracts for the period from September 1, 1996, through December
       31, 1996, was $1,314,732.05. The aggregate amount recovered from sales of
       repossessed manufactured homes during the period was $3,189,290.92.

       At December 31, 1996, there were four hundred thirty six (436) accounts
       with an aggregate principal balance of $10,974,907.99 that were 30-59
       days delinquent, one hundred thirty one (131) accounts with an aggregate
       principal balance of $3,446,639.11 that were 60-89 days delinquent, and
       one hundred fifty two (152) accounts with an aggregate principal balance
       of $4,165,673.67 that was 90 or more days delinquent. The foregoing
       delinquent balances represent 1.193%, 0.241%, 0.213% respectively, of the
       outstanding pool balance as of December 31, 1996 (1.647% in total).

       FCFC transferred its manufactured housing finance business, including the
       Contracts and related servicing, to Associates Housing Finance LLC
       (formally, Associates Housing Finance Services, Inc.), a wholly-owned
       subsidiary of Associates First Capital Corporation, effective as of March
       1, 1997.

Item 3.   Legal Proceedings.

          The Registrant knows of no material legal proceedings with respect to
          the Trust, involving the Trust, the Trustee or the Company, as
          Servicer of the Receivables, other than ordinary routine litigation
          incidental to the Trustee's or the Company's servicing duties under
          the Agreement.

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

          No matter was submitted during the period covered by this report to a
          vote of the Certificateholders.


<PAGE>


                                     PART II

Item 5.   Market for Registrant's Common Equity and Related Stockholder
          Matters.

          (a)  CS First Boston, Goldman Sachs & Co. and Morgan Stanley and Co.
               have informed the Company that, while they have been prepared to
               quote prices to institutional investors for the purchase and sale
               of Certificates, to the best of their knowledge, there have been
               only limited sporadic quotations for the purchase and sale of
               Certificates.

          (b)  As of December 31, 1996, there was one (1) Certificateholder of
               record, Cede & Co. as nominee for the Depository Trust Company
               ("DTC").

          (c)  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 8.   Financial Statement and Supplementary Data.

          Not Applicable.

Item 9.   Changes In and Disagreements with Accountants on Accounting and
          Financial Disclosure.

          None.


<PAGE>


                                    PART III

Item 10.  Directors and Executive Officers of the Registrant.

          Not Applicable.

Item 11.  Executive Compensation.

          Not Applicable.

Item 12.  Security Ownership of Certain Beneficial Owners and Management.

          (a)  To the best knowledge of the registrant, as of December 31,
               1996, there was one (1) Certificateholder of record for each
               class of certificates, Cede & Co. as nominee for DTC, whose
               participating members in aggregate owned of record in excess of
               five percent (5%) of the interest represented by the
               certificates, as set forth in the table below.  The Registrant
               has no knowledge of whether any of such participating member of
               DTC is a "Beneficial owner" ( as that term is defined in Rule
               13d-3 under the Securities Exchange Act of 1934), of the
               Certificates held of record.

<TABLE>
<CAPTION>

                       Name and Address           Amount and Nature    Percent
Title of Class                of                         of              of
                       Certificateholder         Certificate Holdings   Class
------------------------------------------------------------------------------
<S>                    <C>                       <C>                   <C>
Associates Manufactured Cede & Co.                4,300                 23.36%
Housing Contract        P.O. Box 20               Certificates
Series 1996-1 6.20%     Bowling Green Station     representing
Asset Backed            New York, NY  10274       $215,000,000.00 <F1>
Certificates,
Class A-1

Associates Manufactured Cede & Co.                2,940                 15.98%
Housing Contract        P.O. Box 20               Certificates
Series 1996-1 6.70%     Bowling Green Station     representing
Asset Backed            New York, NY  10274       $147,000,000.00 <F1>
Certificates,
Class A-2

Associates Manufactured Cede & Co.                2,740                 14.89%
Housing Contract        P.O. Box 20               Certificates
Series 1996-1 7.00%     Bowling Green Station     representing
Asset Backed            New York, NY  10274       $137,000,000.00 <F1>
Certificates,
Class A-3
</TABLE>


<PAGE>

<TABLE>
<S>                    <C>                       <C>                   <C>
Associates Manufactured Cede & Co.                1,440                  7.82%
Housing Contract        P.O. Box 20               Certificates
Series 1996-1 7.30%     Bowling Green Station     representing
Asset Backed            New York, NY  10274       $72,000,000.00  <F1>
Certificates,
Class A-4

Associates Manufactured Cede & Co.                3,672                 19.95%
Housing Contract        P.O. Box 20               Certificates
Series 1996-1 7.60%     Bowling Green Station     representing
Asset Backed            New York, NY  10274       $183,573,000.00 <F1>
Certificates,
Class A-5

Associates Manufactured Cede & Co.                1,288                  7.00%
Housing Contract        P.O. Box 20               Certificates
Series 1996-1 7.90%     Bowling Green Station     representing
Asset Backed            New York, NY  10274       $64,414,000.00  <F1>
Certificates,
Class M

Associates Manufactured Cede & Co.                1,380                  7.50%
Housing Contract        P.O. Box 20               Certificates
Series 1996-1 8.00%     Bowling Green Station     representing
Asset Backed            New York, NY  10274       $69,015,000.00  <F1>
Certificates,
Class B-1

Associates Manufactured Cede & Co.                644                    3.50%
Housing Contract        P.O. Box 20               Certificates
Series 1996-1 9.00%     Bowling Green Station     representing
Asset Backed            New York, NY  10274       $32,209,764.40  <F1>
Certificates,
Class B-2
</TABLE>

[FN]

 <F1>  Each Certificate represented $50,000 on date of issuance and $48,225.50
       as of December 31, 1996. As of December 31, 1996, the aggregate
       outstanding principal amount of Certificates was $887,553,664.57.

</FN>

          (b)  Not Applicable.

          (c)  Not Applicable.


<PAGE>



Item 13.  Certain Relationships and Related Transactions.

          (a)  The Registrant knows of no transaction or series of similar
               transactions during the period from inception (September 1,
               1996) through December 31, 1996, or any currently proposed
               transaction or series of similar transactions to which the
               Trustee or the Trust has been or will be a party, involving an
               amount exceeding $60,000 and in which any Certificateholder or
               any beneficial owner, in either case, who owns more than five
               percent of the interest represented by the Certificates, or any
               member of the immediate family of any Certificateholder of
               beneficial owner, had or will have a direct or indirect
               material interest.


          (b)  Not Applicable.

          (c)  Not Applicable.

                                     PART IV

Item 14.  Exhibits, Financial Statement Schedules, and Reports on Form 8-K.

          (a)  The attached report of Coopers & Lybrand L.L.P. regarding the
               servicing activities of the Company, prepared pursuant to ARTICLE
               XIII, Section 13.11. of the Standard Terms and Conditions of the
               Agreement, is filed as Exhibit 99.

          (b)  In its request for a no-action letter (which letter was issued by
               the Commission on September 19, 1991), Associates Housing Finance
               Services Inc., on behalf of the Registrant, proposed to
               include herein as an exhibit the Annual Report required to be
               issued following the end of each calendar year by the Trustee
               regarding distributions made to Certificateholders in the prior
               year. The Registrant files herewith as Exhibit 19(b) the
               Trustee's Report for December 1996 as part of the annual report
               for the calendar year 1996 pursuant to ARTICLE XIV, Section 14.11
               of the Standard Terms and Conditions of the Agreement is filed as
               part of this Report.

          (c)  Servicer's Certificate for December 1996 is filed as Exhibit
               19(a).


<PAGE>


                                   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.

                                   Associates Manufactured Housing Contract
                                   Pass-Through Certificates, Series 1996-1

                                   By: CS First Boston Mortgage Securities Corp.

Date: June 17, 1999                    By:  /s/ William S. Pitofsky
                                            ----------------------
                                         Name: William S. Pitofsky
                                         Title: Attorney-in-fact


<PAGE>


                                INDEX TO EXHIBITS

 <TABLE>
 <CAPTION>
                                                                  SEQUENTIALLY
 EXHIBIT                                                            NUMBERED
 NUMBER                    EXHIBIT                                    PAGE
 -----------------------------------------------------------------------------
 <S>     <C>                                                      <C>
 19(a)    Servicer's Certificate for December, 1996
 19(b)    Trustee's Report
 99       Report of Independent Public Accountants




</TABLE>