<PAGE>

                      SECURITIES AND EXCHANGE COMMISSION
                            WASHINGTON, D.C.  20549

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

                                   FORM 10-K

                       FOR ANNUAL AND TRANSITION REPORTS
                    PURSUANT TO SECTIONS 13 OR 15(d) OF THE
                        SECURITIES EXCHANGE ACT OF 1934

 (X)  ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE
                                  ACT OF 1934

                  For the fiscal year ended December 31, 1999

                                       OR

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

                                                333-1092
                     Commission file number:    333-1092-01

                       Banc One Auto Grantor Trust 1996-A
                       ----------------------------------
                   (Issuer with respect to the Certificates)

                             Bank One, Texas, N.A.
                             ---------------------
             (Exact name of registrant as specified in its charter)

               United States                            75-2270994
               -------------                            -----------
      (State or other jurisdiction                   (I.R.S. Employer
    of incorporation or organization)               Identification No.)

                     1717 Main Street, Dallas, Texas 75201
                     --------------------------------------
               (Address of principal executive offices, zip code)

Registrant's telephone number, including area code:  (214) 290-7437
                                                    ---------------

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

     The Registrant has no officer, director or beneficial owner of more than
10% of equity securities to whom Section 16(a) of the Act applies and
consequently Item 405 of Regulation S-K does not apply.

     The Registrant does not have any voting stock, has not been involved in
bankruptcy proceedings during the past five years and is not a corporate
registrant.

     No documents are incorporated by reference into this Form 10-K.

--------------------------------------------------------------------------------
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This Annual Report on Form 10-K is filed in accordance with a no-action letter
dated August 16, 1995 issued by the Office of Chief Counsel, Division of
Corporation Finance of the Securities and Exchange Commission to Bank One,
Texas, N.A., as originator and servicer of Banc One Auto Trust 1995-A.
Consistent with such no-action letter, certain items have been omitted from or
modified in this Annual Report on Form 10-K.


                                     PART I
Item 1.    Business
           --------

           Omitted.

Item 2.    Properties
           ----------

           The property of Banc One Auto Grantor Trust 1996-A (the "Trust")
           consists of certain motor vehicle retail installment sale contracts
           secured by new or used automobiles, vans or light duty trucks.
           Information regarding the property of the Trust and the activities of
           Bank One, Texas, N.A., as servicer (the "Servicer") during the year
           ended December 31, 1999 is contained in (i) the Annual Servicer's
           Certificate filed as Exhibit 99.1 hereto and (ii) the Annual
           Statement prepared by the Servicer and filed as Exhibit 99.2 hereto.

Item 3.    Legal Proceedings
           -----------------

           Nothing to report.

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

           No matters were submitted to a vote of security holders during 1999.


                                    PART II

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

           Investor Certificates (the "Certificates"), are held and delivered in
           book-entry form through the facilities of the Depository Trust
           Company ("DTC"), a clearing agency registered pursuant to the
           provisions of Section 17A of the Securities Exchange Act of 1934, as
           amended. The Certificates are held by Cede & Co, the nominee of DTC.

                                       2
<PAGE>

           The records of DTC indicate that, at December 31, 1999, there were:
           (i) thirty-four (34) DTC Participants holding a position in the 6.10%
           Class A Asset Backed Certificates, Series 1996-A; and (ii) one (1)
           DTC Participant holding a position in the 6.25% Class B Asset Backed
           Certificates, Series 1996-A. There is no established public market in
           which the Certificates are traded.

Item 6.    Selected Financial Data
           -----------------------

           Omitted.

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

           Throughout 1999, BANK ONE CORPORATION ("BANK ONE"), the parent
           corporation of Bank One, Texas, N.A. (the "Bank"), executed project
           plans to assure Year 2000 readiness. These plans included verifying
           the readiness of internal information technology systems and
           equipment, and working with external entities, including customers,
           vendors, utilities and governmental agencies, to verify that they had
           appropriately addressed Year 2000 readiness issues. Specific business
           continuity and event plans were designed to address potential
           disruption and ensure that BANK ONE was positioned to rapidly respond
           to issues.

           BANK ONE had estimated total Year 2000 readiness costs to reach $350
           million over the life of the project, and incurred total costs of
           approximately $343 million.

           BANK ONE had an uneventful transition to the Year 2000. BANK ONE's
           systems, equipment and facilities continued and continue to function
           normally through the transition and into Year 2000. Normal products
           and services of BANK ONE have been available to customers throughout
           such time, and BANK ONE experienced no significant impact from the
           Year 2000 readiness status of external entities. To meet potential
           Year 2000 contingencies and potential liquidity needs, BANK ONE
           increased the value of loans pledged to the Federal Reserve for
           discount window borrowing.

           On an ongoing basis, BANK ONE will continue to monitor its systems,
           equipment and facilities throughout 2000 and beyond.

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

           Omitted.

Item 8.    Financial Statements and Supplementary Data
           -------------------------------------------

           Omitted.

                                       3
<PAGE>

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

           None.


                                    PART III

Item 10.   Directors and Executive Officers of the Registrant
           --------------------------------------------------

           Omitted.

Item 11.   Executive Compensation
           ----------------------

           Omitted.

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

           At December 31, 1999, the Certificates were registered in the name of
           Cede & Co., as nominee of DTC. The records of DTC indicate that, at
           December 31, 1999, there were four (4) DTC Participants holding
           positions in excess of five (5) percent of any class of outstanding
           Certificates. Such persons are described in the table below:

<TABLE>
<CAPTION>
                                                              Amount and Nature of
                             Name and Address of              Beneficial Ownership      Percent
  Title of Class              Beneficial Owners                     $(000's)            of Class
  --------------              -----------------                     --------            --------
<S>                         <C>                               <C>                       <C>
6.10% Class A                Bank of New York (The)                 $102,249              19.92%
Asset Backed                 925 Patterson Plank Road
Certificates,                Secaucus, NJ 07094
Series 1996-A
                             Chase Manhattan Bank                   $220,135              42.88%
                             4 New York Plaza
                             13th Floor
                             New York, NY 10004

                             State Street Bank & Trust Company       $41,030               7.99%
                             Global Corp. Action Unit JAB 5NW
                             1776 Heritage Dr.
                             No. Quincy, MA  02171
</TABLE>

                                       4
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<TABLE>
<S>                 <C>                                     <C>                        <C>
6.25% Class B           Chase Manhattan Bank                    $24,187                 100.00%
Asset Backed            4 New York Plaza
Certificates,           13th Floor
Series 1996-A           New York, NY 10004
</TABLE>

Item 13.  Certain Relationships and Related Transactions
          ----------------------------------------------

          None.


                                    PART IV

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

          (b)  Reports on Form 8-K

               (i)  Reports on Form 8-K containing the monthly statements and
                    other information reflecting the Trust's activities:
<TABLE>
<CAPTION>


                    Dated:                Items Reported:
                    ------                ---------------
                    <S>                   <C>

                    February 16, 1999     5 and 7
                    March 15, 1999        5 and 7
                    April 15, 1999        5 and 7
                    May 17, 1999          5 and 7
                    June 15, 1999         5 and 7
                    July 15, 1999         5 and 7
                    August 16, 1999       5 and 7
                    September 15, 1999    5 and 7
                    October 15, 1999      5 and 7
                    November 15, 1999     5 and 7
                    December 15, 1999     5 and 7
                    January 18, 2000      5 and 7
</TABLE>
          (c)  Exhibits.  The following documents are filed as part of this
               Annual Report on Form 10-K.

               99.1  Annual Servicer's Certificate
               99.2  Annual Statement
               99.3  Independent Accountants' Report of Arthur Anderson LLP on
                     Management's Assertions

                                       5
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                                   SIGNATURE


     Pursuant to the requirements of Section 13 or 15(d) of the Securities
Exchange Act of 1934, the Registrant has duly caused this report to be signed on
its behalf by the undersigned, thereunto duly authorized.


Date:  March 24, 2000

                         Banc One Auto Grantor Trust 1996-A

                         By:  Bank One, Texas, N.A., as Servicer, on
                              behalf of the Trust

                         By:  /s/ Tracie H. Klein
                              ________________________________
                         Name:  Tracie H. Klein
                         Title: Vice President


SUPPLEMENTAL INFORMATION TO BE FURNISHED WITH REPORTS FILED PURSUANT TO SECTION
15(d) OF THE ACT BY REGISTRANTS WHICH HAVE NOT REGISTERED SECURITIES PURSUANT TO
SECTION 12 OF THE ACT.

No annual report, proxy statement, form of proxy or other proxy soliciting
material has been sent to Certificateholders during the period covered by this
Annual Report on Form 10-K and the Registrant does not intend to furnish such
materials to Certificateholders subsequent to the filing of this report.

                                       6
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                               INDEX OF EXHIBITS



Exhibit    Description                                  Page
-------    -----------                                  -----

99.1       Annual Servicer's Certificate                    8

99.2       Annual Statement                                 9

99.3       Independent Accountants' Report of           10-11
           Arthur Andersen LLP on Management's
           Assertions

                                       7