<PAGE>   1
 
================================================================================
 
                                 UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549
                            ------------------------
 
   
                                 FORM 10-K/A-2
    
 
(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, 1997
 
                                       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 0-26146
 
                               HNC SOFTWARE INC.
             (EXACT NAME OF REGISTRANT AS SPECIFIED IN ITS CHARTER)
 
<TABLE>
<S>                                              <C>
                    DELAWARE                                        33-0248788
        (STATE OR OTHER JURISDICTION OF                          (I.R.S. EMPLOYER
         INCORPORATION OR ORGANIZATION)                        IDENTIFICATION NO.)
</TABLE>
 
                5930 CORNERSTONE COURT WEST, SAN DIEGO, CA 92121
                    (ADDRESS OF PRINCIPAL EXECUTIVE OFFICES)
 
       REGISTRANT'S TELEPHONE NUMBER, INCLUDING AREA CODE: (619) 546-8877
 
          SECURITIES REGISTERED PURSUANT TO SECTION 12(B) OF THE ACT:
                                      NONE
 
          SECURITIES REGISTERED PURSUANT TO SECTION 12(G) OF THE ACT:
                         COMMON STOCK, $0.001 PAR VALUE
                                (TITLE OF CLASS)
 
     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 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. [ ]
 
     The aggregate market value of the voting stock held by non-affiliates of
the Registrant, based on the closing price as reported on the Nasdaq Stock
Market at January 30, 1998, was approximately $809 million. The number of shares
of the Registrant's Common Stock outstanding at January 30, 1998 was 24,570,578
shares.
 
                      DOCUMENTS INCORPORATED BY REFERENCE
 
     Portions of the Proxy Statement for Registrant's 1998 Annual Meeting of
Stockholders to be filed with the Commission on or before April 30, 1998 are
incorporated by reference in Part III of this Annual Report on Form 10-K. With
the exception of those portions that are specifically incorporated by reference
in this Annual Report on Form 10-K, such Proxy Statement shall not be deemed
filed as part of this Report or incorporated by reference herein.
================================================================================
<PAGE>   2
 
   
ITEM 14. EXHIBITS, FINANCIAL STATEMENT SCHEDULES AND REPORTS ON FORM 8-K
    
 
   
     (a) The following documents are filed as part of this report:
    
 
   
         3.  Exhibits
    
 
<TABLE>
<CAPTION>
                     EXHIBIT
                      NUMBER                           DESCRIPTION
                     --------                          -----------
                     <S>       <C>
                      2.01     Agreement and Plan of Reorganization dated as of July 19,
                               1996 by and among the Registrant, HNC Merger Corp. and Risk
                               Data Corporation, as amended. (Incorporated by reference to
                               Exhibit Number 2.01 to Registrant's Current Report on Form
                               8-K filed on September 12, 1996, as amended (the "Risk Data
                               8-K").)
                      2.02     Agreement of Merger dated August 30, 1996 by and between HNC
                               Merger Corp. and Risk Data Corporation. (Incorporated by
                               reference to Exhibit Number 2.02 to the Risk Data 8-K.)
                      2.03     Exchange Agreement dated as of October 25, 1996 by and among
                               the Registrant, Retek Distribution Corporation and the
                               shareholders of Retek Distribution Corporation.
                               (Incorporated by reference to Exhibit Number 2.01 to
                               Registrant's Current Report on Form 8-K filed on December
                               12, 1996 (the "Retek 8-K").)
                      2.04     Form of Option Exchange Agreement between the Registrant and
                               each person who held outstanding options to purchase shares
                               of Retek Distribution Corporation on November 29, 1996.
                               (Incorporated by reference to Exhibit Number 2.02 to the
                               Retek 8-K.)
                      2.05     Agreement and Plan of Reorganization dated as of July 14,
                               1997 by and among the Registrant, FW1 Acquisition Corp.,
                               CompReview, Inc., Robert L. Kaaren and Mishel E. Munnayer,
                               a.k.a. Michael Munayyer, Trustee of the Michael Munayyer
                               Trust dated August 11, 1995. (Pursuant to Item 601(b)(2) of
                               Regulation S-K, certain schedules have been omitted but will
                               be furnished supplementally to the Commission upon request.)
                               (Incorporated by reference to Exhibit Number 2.01 to
                               Registrant's Current Report on Form 8-K filed on December
                               15, 1997 (the "CompReview 8-K").)
                      2.06     Agreement of Merger dated as of November 28, 1997 by and
                               between FW1 Acquisition Corp. and CompReview, Inc.
                               (Incorporated by reference to Exhibit Number 2.02 to the
                               CompReview 8-K.)
                      3(i).01  Registrant's Restated Certificate of Incorporation filed
                               with the Secretary of State of Delaware on June 13, 1996.
                               (Incorporated by reference to Exhibit Number 3(i).04 to
                               Registrant's Quarterly Report on Form 10-Q for the quarter
                               ended June 30, 1996 (the "Second Quarter 1996 10-Q").)
                               Registrant's Bylaws, as amended. (Incorporated by reference
                     3(ii).02  to Exhibit Number 3(ii).05 to the Second Quarter 1996 10-Q.)
                      4.01     Form of Specimen Certificate for Registrant's Common Stock.
                               (Incorporated by reference to Exhibit Number 4.01 to
                               Registrant's Form S-1 Registration Statement, as amended
                               (File No. 33-91932) (the "IPO S-1").)
                      4.02     Third Amended Registration Rights Agreement dated March 10,
                               1993, as amended. (Incorporated by reference to Exhibit
                               Number 4.02 to the IPO S-1.)
                      4.03     Second Waiver and Amendment to Third Amended Registration
                               Rights Agreement. (Incorporated by reference to Exhibit
                               Number 4.03 to Registrant's Form S-1 Registration Statement,
                               as amended (File No. 33-99980) (the "Second S-1").)
                      4.04     Registration Rights Agreement dated as of August 30, 1996 by
                               and among the Registrant and the former shareholders of Risk
                               Data Corporation. (Incorporated by reference to Exhibit
                               Number 4.01 to the Risk Data 8-K.)
</TABLE>
<PAGE>   3
 
<TABLE>
<CAPTION>
                     EXHIBIT
                      NUMBER                           DESCRIPTION
                     --------                          -----------
                     <S>       <C>
                      4.05     Registration Rights Agreement dated as of October 25, 1996
                               by and among the Registrant and the former shareholders of
                               Retek Distribution Corporation. (Incorporated by reference
                               to Exhibit Number 4.01 to the Retek 8-K.)
                      4.06     Amendment No. 1 to the Registration Rights Agreement dated
                               as of February 24, 1997 by and between the Registrant and
                               the former shareholders of Retek Distribution Corporation.
                               (Incorporated by reference to Exhibit Number 4.06 to
                               Registrant's Annual Report on Form 10-K, as amended, for the
                               year ended December 31, 1996 (the "1996 10-K").)
                      4.07     Registration Rights Agreement dated as of November 28, 1997
                               by and among the Registrant and the former shareholders of
                               CompReview, Inc. (Incorporated by reference to Exhibit
                               Number 4.01 to the CompReview 8-K.)
                     10.01     Registrant's 1987 Stock Option Plan and related documents.
                               (Incorporated by reference to Exhibit Number 10.01 to the
                               IPO S-1.)(1)
                     10.02     Registrant's 1995 Equity Incentive Plan and related
                               documents, as amended.(1)
                     10.03     Registrant's 1995 Directors Stock Option Plan and related
                               documents. (Incorporated by reference to Exhibit Number
                               10.03 to the IPO S-1.)(1)
                     10.04     Registrant's 1995 Employee Stock Purchase Plan and related
                               documents. (Incorporated by reference to Exhibit Number
                               10.04 to the IPO S-1.)(1)
                     10.05     Registrant's 1998 Stock Option Plan.(1)
                     10.06     Form of Indemnity Agreement entered into by Registrant with
                               each of its directors and executive officers. (Incorporated
                               by reference to Exhibit Number 10.08 to the IPO S-1.)(1)
                     10.07     Office Building Lease dated as of December 1, 1993, as
                               amended effective February 1, 1994 and June 1, 1994, between
                               Registrant and PacCor Partners. (Incorporated by reference
                               to Exhibit Number 10.09 to the IPO S-1.)
                     10.08     Marketing Agreement dated as of June 24, 1993 between
                               Registrant and First Data Resources, Inc. (Incorporated by
                               reference to Exhibit Number 10.11 to the IPO S-1.)(2)
                     10.09     License Agreement dated as of June 24, 1993, as amended
                               October 18, 1993, September 16, 1994 and by letter
                               amendment, with Addendum dated January 21, 1994, as amended
                               February 15, 1995, between Registrant and First Data
                               Resources, Inc. (Incorporated by reference to Exhibit Number
                               10.12 to the IPO S-1.)(2)
                     10.10     Loan and Security Agreement dated as of July 11, 1997,
                               between Registrant and Wells Fargo Bank, National
                               Association. (Incorporated by reference to Exhibit Number
                               10.01 to Registrant's Quarterly Report on Form 10-Q, as
                               amended, for the quarter ended June 30, 1997 (the "Second
                               Quarter 1997 10-Q").)
                     10.11     Office Building Lease dated as of May 30, 1997, between
                               Retek Information Systems, Inc. and Midwest Real Estate
                               Holdings, Inc. (Incorporated by reference to Exhibit Number
                               10.02 to the Second Quarter 1997 10-Q.)
                     10.12     Office Building Lease dated as of June 17, 1996, between
                               Registrant and Williams Properties I, LLC & Williams
                               Properties II, LLC. (Incorporated by reference to Exhibit
                               Number 10.12 to the 1996 10-K.)
                     10.13     Employment Agreement dated as of September 10, 1996, by and
                               between Aptex Software Inc. and Michael A. Thiemann.
                               (Incorporated by reference to Exhibit Number 10.13 to the
                               1996 10-K.)(1)
</TABLE>
<PAGE>   4
 
   
<TABLE>
<CAPTION>
                     EXHIBIT
                      NUMBER                           DESCRIPTION
                     --------                          -----------
                     <S>       <C>
                     10.14     Investors' Rights Agreement dated as of September 10, 1996,
                               by and among Aptex Software Inc., HNC Software Inc. and
                               Michael A. Thiemann. (Incorporated by reference to Exhibit
                               Number 10.14 to the 1996 10-K.)(1)
                     10.15     Restricted Stock Purchase Agreement dated as of September
                               10, 1996, by and between Aptex Software Inc. and Michael
                               Thiemann. (Incorporated by reference to Exhibit Number 10.15
                               to the 1996 10-K.)(1)
                     10.16     Aptex Software Inc.'s 1996 Equity Incentive Plan and related
                               documents. (Incorporated by reference to Exhibit Number
                               10.16 to the 1996 10-K.)(1)
                     10.17     Office Building Lease dated June 17, 1993, between
                               Linsco/Private Ledger Corp. and PacCor Partners and
                               Assignment of such lease to the Registrant.
                     21.01     List of Registrant's subsidiaries.
                     23.01     Consent of Price Waterhouse LLP, Independent Accountants.
                     27.01     Financial Data Schedule (December 31, 1997)
                     *27.02    Restated Financial Data Schedule (September 30, 1997)
                     *27.03    Restated Financial Data Schedule (June 30, 1997)
                     *27.04    Restated Financial Data Schedule (March 31, 1997)
                     *27.05    Restated Financial Data Schedule (December 31, 1996)
                     *27.06    Restated Financial Data Schedule (September 30, 1996)
                     *27.07    Restated Financial Data Schedule (June 30, 1996)
                     *27.08    Restated Financial Data Schedule (March 31, 1996)
                     *27.09    Restated Financial Data Schedule (December 31, 1995)
</TABLE>
    
 
---------------
 
 *  Filed herewith.
 
(1) Management contract or compensatory plan or arrangement.
 
   
(2) Confidential treatment has been granted for certain portions of this
    document. Such portions have been omitted from the filing and have been
    filed separately with the Securities and Exchange Commission.
    
   
    
<PAGE>   5
 
                                   SIGNATURES
 
     Pursuant to the requirements of Section 13 or 15(d) of the Securities
Exchange Act of 1934, the Registrant has duly caused this amendment to report to
be signed on its behalf by the undersigned, thereunto duly authorized.
 
   
Date: April 10, 1998                      HNC SOFTWARE INC.
    
 
                                          By:     /s/ RAYMOND V. THOMAS
                                            ------------------------------------
                                                     Raymond V. Thomas
                                                 Vice President, Finance &
                                                        Administration
                                                and Chief Financial Officer
 
     Pursuant to the requirements of the Securities Exchange Act of 1934, this
amendment to report has been signed below by the following persons on behalf of
the Registrant and in the capacities and on the dates indicated.
 
   
<TABLE>
<CAPTION>
                      SIGNATURE                                     TITLE                       DATE
                      ---------                                     -----                       ----
<C>                                                      <S>                             <C>
 
                 /s/ ROBERT L. NORTH                     President and Chief                 April 10, 1998
-----------------------------------------------------    Executive Officer (Principal
                   Robert L. North                       Executive Officer)
 
                /s/ RAYMOND V. THOMAS                    Vice President, Finance &           April 10, 1998
-----------------------------------------------------    Administration and Chief
                  Raymond V. Thomas                      Financial Officer (Principal
                                                         Financial Officer and
                                                         Principal Accounting
                                                         Officer)
 
               /s/ EDWARD K. CHANDLER                    Director                            April 10, 1998
-----------------------------------------------------
                 Edward K. Chandler
 
                 /s/ OLIVER D. CURME                     Director                            April 10, 1998
-----------------------------------------------------
                   Oliver D. Curme
 
                 /s/ THOMAS F. FARB                      Director                            April 10, 1998
-----------------------------------------------------
                   Thomas F. Farb
 
                                                         Director                            April 10, 1998
-----------------------------------------------------
               Charles H. Gaylord, Jr.
</TABLE>
    
 
                                       61
<PAGE>   6
 
                                 EXHIBIT INDEX
 
<TABLE>
<CAPTION>
EXHIBIT
 NUMBER                          EXHIBIT TITLE
--------                         -------------
<C>       <S>
    2.01  Agreement and Plan of Reorganization dated as of July 19,
          1996 by and among the Registrant, HNC Merger Corp. and Risk
          Data Corporation, as amended. (Incorporated by reference to
          Exhibit Number 2.01 to Registrant's Current Report on Form
          8-K filed on September 12, 1996, as amended (the "Risk Data
          8-K").).....................................................
    2.02  Agreement of Merger dated August 30, 1996 by and between HNC
          Merger Corp. and Risk Data Corporation. (Incorporated by
          reference to Exhibit Number 2.02 to the Risk Data 8-K.).....
    2.03  Exchange Agreement dated as of October 25, 1996 by and among
          the Registrant, Retek Distribution Corporation and the
          shareholders of Retek Distribution Corporation.
          (Incorporated by reference to Exhibit Number 2.01 to
          Registrant's Current Report on Form 8-K filed on December
          12, 1996 (the "Retek 8-K").)................................
    2.04  Form of Option Exchange Agreement between the Registrant and
          each person who held outstanding options to purchase shares
          of Retek Distribution Corporation on November 29, 1996.
          (Incorporated by reference to Exhibit Number 2.02 to the
          Retek 8-K.).................................................
    2.05  Agreement and Plan of Reorganization dated as of July 14,
          1997 by and among the Registrant, FW1 Acquisition Corp.,
          CompReview, Inc., Robert L. Kaaren and Mishel E. Munnayer,
          a.k.a. Michael Munayyer, Trustee of the Michael Munayyer
          Trust dated August 11, 1995. (Pursuant to Item 601(b)(2) of
          Regulation S-K, certain schedules have been omitted but will
          be furnished supplementally to the Commission upon request.)
          (Incorporated by reference to Exhibit Number 2.01 to
          Registrant's Current Report on Form 8-K filed on December
          15, 1997 (the "CompReview 8-K").)...........................
    2.06  Agreement of Merger dated as of November 28, 1997 by and
          between FW1 Acquisition Corp. and CompReview, Inc.
          (Incorporated by reference to Exhibit Number 2.02 to the
          CompReview 8-K.)............................................
 3(i).01  Registrant's Restated Certificate of Incorporation filed
          with the Secretary of State of Delaware on June 13, 1996.
          (Incorporated by reference to Exhibit Number 3(i).04 to
          Registrant's Quarterly Report on Form 10-Q for the quarter
          ended June 30, 1996 (the "Second Quarter 1996 10-Q").)......
3(ii).02  Registrant's Bylaws, as amended. (Incorporated by reference
          to Exhibit Number 3(ii).05 to the Second Quarter 1996
          10-Q.)......................................................
    4.01  Form of Specimen Certificate for Registrant's Common Stock.
          (Incorporated by reference to Exhibit Number 4.01 to
          Registrant's Form S-1 Registration Statement, as amended
          (File No. 33-91932) (the "IPO S-1").).......................
    4.02  Third Amended Registration Rights Agreement dated March 10,
          1993, as amended. (Incorporated by reference to Exhibit
          Number 4.02 to the IPO S-1.)................................
    4.03  Second Waiver and Amendment to Third Amended Registration
          Rights Agreement. (Incorporated by reference to Exhibit
          Number 4.03 to Registrant's Form S-1 Registration Statement,
          as amended (File No. 33-99980) (the "Second S-1").).........
    4.04  Registration Rights Agreement dated as of August 30, 1996 by
          and among the Registrant and the former shareholders of Risk
          Data Corporation. (Incorporated by reference to Exhibit
          Number 4.01 to the Risk Data 8-K.)..........................
    4.05  Registration Rights Agreement dated as of October 25, 1996
          by and among the Registrant and the former shareholders of
          Retek Distribution Corporation. (Incorporated by reference
          to Exhibit Number 4.01 to the Retek 8-K.)...................
    4.06  Amendment No. 1 to the Registration Rights Agreement dated
          as of February 24, 1997 by and between the Registrant and
          the former shareholders of Retek Distribution Corporation.
          (Incorporated by reference to Exhibit Number 4.06 to
          Registrant's Annual Report on Form 10-K, as amended, for the
          year ended December 31, 1996 (the "1996 10-K").)............
    4.07  Registration Rights Agreement dated as of November 28, 1997
          by and among the Registrant and the former shareholders of
          CompReview, Inc. (Incorporated by reference to Exhibit
          Number 4.01 to the CompReview 8-K.).........................
   10.01  Registrant's 1987 Stock Option Plan and related documents.
          (Incorporated by reference to Exhibit Number 10.01 to the
          IPO S-1.)(1)................................................
   10.02  Registrant's 1995 Equity Incentive Plan and related
          documents, as amended.(1)...................................
   10.03  Registrant's 1995 Directors Stock Option Plan and related
          documents. (Incorporated by reference to Exhibit Number
          10.03 to the IPO S-1.)(1)...................................
</TABLE>
<PAGE>   7
 
   
<TABLE>
<CAPTION>
EXHIBIT
 NUMBER                          EXHIBIT TITLE
--------                         -------------
<C>       <S>
   10.04  Registrant's 1995 Employee Stock Purchase Plan and related
          documents. (Incorporated by reference to Exhibit Number
          10.04 to the IPO S-1.)(1)...................................
    
   
   10.05  Registrant's 1998 Stock Option Plan.(1).....................
   10.06  Form of Indemnity Agreement entered into by Registrant with
          each of its directors and executive officers. (Incorporated
          by reference to Exhibit Number 10.08 to the IPO S-1.)(1)....
   10.07  Office Building Lease dated as of December 1, 1993, as
          amended effective February 1, 1994 and June 1, 1994, between
          Registrant and PacCor Partners. (Incorporated by reference
          to Exhibit Number 10.09 to the IPO S-1.)....................
   10.08  Marketing Agreement dated as of June 24, 1993 between
          Registrant and First Data Resources, Inc. (Incorporated by
          reference to Exhibit Number 10.11 to the IPO S-1.)(2).......
   10.09  License Agreement dated as of June 24, 1993, as amended
          October 18, 1993, September 16, 1994 and by letter
          amendment, with Addendum dated January 21, 1994, as amended
          February 15, 1995, between Registrant and First Data
          Resources, Inc. (Incorporated by reference to Exhibit Number
          10.12 to the IPO S-1.)(2)...................................
   10.10  Loan and Security Agreement dated as of July 11, 1997,
          between Registrant and Wells Fargo Bank, National
          Association. (Incorporated by reference to Exhibit Number
          10.01 to Registrant's Quarterly Report on Form 10-Q, as
          amended, for the quarter ended June 30, 1997 (the "Second
          Quarter 1997 10-Q"))........................................
   10.11  Office Building Lease dated as of May 30, 1997, between
          Retek Information Systems, Inc. and Midwest Real Estate
          Holdings, Inc. (Incorporated by reference to Exhibit Number
          10.02 to the Second Quarter 1997 10-Q.).....................
   10.12  Office Building Lease dated as of June 17, 1996, between
          Registrant and Williams Properties I, LLC & Williams
          Properties II, LLC. (Incorporated by reference to Exhibit
          Number 10.12 to the 1996 10-K.).............................
   10.13  Employment Agreement dated as of September 10, 1996, by and
          between Aptex Software Inc. and Michael A. Thiemann.
          (Incorporated by reference to Exhibit Number 10.13 to the
          1996 10-K.)(1)..............................................
   10.14  Investors' Rights Agreement dated as of September 10, 1996,
          by and among Aptex Software Inc., HNC Software Inc. and
          Michael A. Thiemann. (Incorporated by reference to Exhibit
          Number 10.14 to the 1996 10-K.)(1)..........................
   10.15  Restricted Stock Purchase Agreement dated as of September
          10, 1996, by and between Aptex Software Inc. and Michael
          Thiemann. (Incorporated by reference to Exhibit Number 10.15
          to the 1996 10-K.)(1).......................................
   10.16  Aptex Software Inc.'s 1996 Equity Incentive Plan and related
          documents. (Incorporated by reference to Exhibit Number
          10.16 to the 1996 10-K.)(1).................................
    
   
   10.17  Office Building Lease dated June 17, 1993, between
          Linsco/Private Ledger Corp. and PacCor Partners and
          Assignment of such lease to the Registrant..................
    
   
   21.01  List of Registrant's subsidiaries...........................
    
   
   23.01  Consent of Price Waterhouse LLP, Independent Accountants....
    
   
   27.01  Financial Data Schedule (December 31, 1997).................
  *27.02  Restated Financial Data Schedule (September 30, 1997).......
  *27.03  Restated Financial Data Schedule (June 30, 1997)............
  *27.04  Restated Financial Data Schedule (March 31, 1997)...........
  *27.05  Restated Financial Data Schedule (December 31, 1996)........
  *27.06  Restated Financial Data Schedule (September 30, 1996).......
  *27.07  Restated Financial Data Schedule (June 30, 1996)............
  *27.08  Restated Financial Data Schedule (March 31, 1996)...........
  *27.09  Restated Financial Data Schedule (December 31, 1995)........
</TABLE>
    
 
---------------
 
 *  Filed herewith.
 
(1) Management contract or compensatory plan or arrangement.
 
(2) Confidential treatment has been granted for certain portions of this
    document. Such portions have been omitted from the filing and have been
    filed separately with the Securities and Exchange Commission.