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                                                                   EXHIBIT 10.05
 
                               HNC SOFTWARE INC.
 
                             1998 STOCK OPTION PLAN
                          As Adopted February 13, 1998
 
     1. PURPOSE. The purpose of this Plan is to provide incentives to attract,
retain and motivate eligible persons whose present and potential contributions
are important to the success of the Company, its Parent, Subsidiaries and
Affiliates, by offering them an opportunity to participate in the Company's
future performance through awards of Options. Capitalized terms not defined in
the text are defined in Section 21.
 
     2. SHARES SUBJECT TO THE PLAN.
 
     2.1  Number of Shares Available. Subject to Sections 2.2 and 16, the total
number of Shares reserved and available for grant and issuance pursuant to this
Plan will be 1,000,000 Shares plus any Shares that are made available for grant
and issuance under this Plan pursuant to the following sentence. Subject to
Sections 2.2 and 16, Shares that are subject to issuance upon exercise of an
Option but cease to be subject to such Option for any reason other than exercise
of such Option will again be available for grant and issuance in connection with
future Options under this Plan. At all times the Company shall reserve and keep
available a sufficient number of Shares as shall be required to satisfy the
requirements of all outstanding Options granted under this Plan.
 
     2.2  Adjustment of Shares. In the event that the number of outstanding
Shares is changed by a stock dividend, recapitalization, stock split, reverse
stock split, subdivision, combination, reclassification or similar change in the
capital structure of the Company without consideration, then the number of
Shares reserved for issuance under this Plan and the Exercise Prices of and
number of Shares subject to outstanding Options will be proportionately
adjusted, subject to any required action by the Board or the stockholders of the
Company and compliance with applicable securities laws; provided, however, that
fractions of a Share will not be issued but will either be replaced by a cash
payment equal to the Fair Market Value of such fraction of a Share or will be
rounded up to the nearest whole Share, as determined by the Committee.
 
     3. ELIGIBILITY. All Options issued under the Plan shall be nonqualified
stock options. Options may be granted to employees, officers, consultants,
independent contractors and advisors of the Company or any Parent, Subsidiary or
Affiliate of the Company; provided that Options awarded to officers of the
Company or any Parent, Subsidiary or Affiliate of the Company may not exceed 30%
of all Options that are available for grant under the Plan and provided further
that such consultants, independent contractors and advisors render bona fide
services not in connection with the offer and sale of securities in a
capital-raising transaction. No person will be eligible to receive more than
50,000 Shares in any calendar year under this Plan pursuant to the grant of
Options hereunder, other than new employees of the Company or of a Parent,
Subsidiary or Affiliate of the Company who are eligible to receive up to a
maximum of 75,000 Shares in the calendar year in which they commence their
employment. A person may be granted more than one Option under this Plan.
 
     4. ADMINISTRATION.
 
     4.1  Committee Authority. This Plan will be administered by the Committee
or by the Board acting as the Committee. Subject to the general purposes, terms
and conditions of this Plan, and to the direction of the Board, the Committee
will have full power to implement and carry out this Plan. Without limitation,
the Committee will have the authority to:
 
     (a) construe and interpret this Plan, any Stock Option Agreement and any
         other agreement or document executed pursuant to this Plan;
 
     (b) prescribe, amend and rescind rules and regulations relating to this
         Plan;
 
     (c) select persons to receive Options;
 
     (d) determine the form and terms of Options;
 
     (e) determine the number of Shares or other consideration subject to
         Options;
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     (f) determine whether Options will be granted singly, in combination with,
         in tandem with, in replacement of, or as alternatives to, other Options
         under this Plan or any other incentive or compensation plan of the
         Company or any Parent, Subsidiary or Affiliate of the Company;
 
     (g) grant waivers of Plan or Option conditions;
 
     (h) determine the vesting, exercisability and payment of Options;
 
     (i) correct any defect, supply any omission or reconcile any inconsistency
         in this Plan, any Option or any Stock Option Agreement;
 
     (j) determine whether an Option has been earned; and
 
     (k) make all other determinations necessary or advisable for the
         administration of this Plan.
 
     4.2  Committee Discretion. Any determination made by the Committee with
respect to any Option will be made in its sole discretion at the time of grant
of the Option or, unless in contravention of any express term of this Plan or
Option, at any later time, and such determination will be final and binding on
the Company and on all persons having an interest in any Option under this Plan.
The Committee may delegate to one or more officers of the Company the authority
to grant Options under this Plan.
 
     5. OPTIONS. The Committee may grant Options to eligible persons and will
determine the number of Shares subject to the Option, the Exercise Price of the
Option, the period during which the Option may be exercised, and all other terms
and conditions of the Option, subject to the following:
 
     5.1  Form of Option Grant. Each Option granted under this Plan will be
evidenced by a Stock Option Agreement, which will be in such form and contain
such provisions (which need not be the same for each Participant) as the
Committee may from time to time approve, and which will comply with and be
subject to the terms and conditions of this Plan.
 
     5.2  Date of Grant. The date of grant of an Option will be the date on
which the Committee makes the determination to grant such Option, unless
otherwise specified by the Committee. The Stock Option Agreement and a copy of
this Plan will be delivered to the Participant within a reasonable time after
the granting of the Option.
 
     5.3  Exercise Period. Options will be exercisable within the times or upon
the events determined by the Committee as set forth in the Stock Option
Agreement governing such Option; provided, however, that no Option will be
exercisable after the expiration of ten (10) years from the date the Option is
granted. The Committee also may provide for the exercise of Options to become
exercisable at one time or from time to time, periodically or otherwise, in such
number of Shares or percentage of Shares as the Committee determines.
 
     5.4  Exercise Price. The Exercise Price of an Option will be determined by
the Committee when the Option is granted and may not be less than 100% of the
Fair Market Value of the Shares on the date of grant. Payment for the Shares
purchased may be made in accordance with Section 6 of this Plan.
 
     5.5  Method of Exercise. Options may be exercised only by delivery to the
Company of a written stock option exercise agreement (the "EXERCISE AGREEMENT")
in a form approved by the Committee (which need not be the same for each
Participant), stating the number of Shares being purchased, the restrictions
imposed on the Shares purchased under such Exercise Agreement, if any, and such
representations and agreements regarding Participant's investment intent and
access to information and other matters, if any, as may be required or desirable
by the Company to comply with applicable securities laws, together with payment
in full of the Exercise Price for the number of Shares being purchased.
 
     5.6  Termination. Notwithstanding the exercise periods set forth in the
Stock Option Agreement, exercise of an Option will always be subject to the
following:
 
     (a) If the Participant is Terminated for any reason except death or
         Disability, then the Participant may exercise such Participant's
         Options only to the extent that such Options would have been
         exercisable upon the Termination Date no later than three (3) months
         after the Termination Date (or such
 
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         shorter or longer time period not exceeding five (5) years as may be
         determined by the Committee), but in any event, no later than the
         expiration date of the Options.
 
     (b) If the Participant is Terminated because of Participant's death or
         Disability (or the Participant dies within three (3) months after a
         Termination other than because of Participant's death or disability),
         then Participant's Options may be exercised only to the extent that
         such Options would have been exercisable by Participant on the
         Termination Date and must be exercised by Participant (or Participant's
         legal representative or authorized assignee) no later than twelve (12)
         months after the Termination Date (or such shorter or longer time
         period not exceeding five (5) years as may be determined by the
         Committee), but in any event no later than the expiration date of the
         Options.
 
     5.7  Limitations on Exercise. The Committee may specify a reasonable
minimum number of Shares that may be purchased on any exercise of an Option,
provided that such minimum number will not prevent Participant from exercising
the Option for the full number of Shares for which it is then exercisable.
 
     5.8  Modification, Extension or Renewal. The Committee may modify, extend
or renew outstanding Options and authorize the grant of new Options in
substitution therefor, provided that any such action may not, without the
written consent of a Participant, impair any of such Participant's rights under
any Option previously granted. The Committee may reduce the Exercise Price of
outstanding Options without the consent of Participants affected by a written
notice to them; provided, however, that the Exercise Price may not be reduced
below the minimum Exercise Price that would be permitted under Section 5.4 of
this Plan for Options granted on the date the action is taken to reduce the
Exercise Price.
 
     6. PAYMENT FOR SHARE PURCHASES.
 
     6.1  Payment. Payment for Shares purchased pursuant to this Plan may be
made in cash (by check) or, where expressly approved for the Participant by the
Committee and where permitted by law:
 
     (a) by cancellation of indebtedness of the Company to the Participant;
 
     (b) by surrender of shares that either: (1) have been owned by Participant
         for more than six (6) months and have been paid for within the meaning
         of SEC Rule 144 (and, if such shares were purchased from the Company by
         use of a promissory note, such note has been fully paid with respect to
         such shares); or (2) were obtained by Participant in the public market;
 
     (c) by tender of a full recourse promissory note having such terms as may
         be approved by the Committee and bearing interest at a rate sufficient
         to avoid imputation of income under Sections 483 and 1274 of the Code;
         provided, however, that Participants who are not employees of the
         Company will not be entitled to purchase Shares with a promissory note
         unless the note is adequately secured by collateral other than the
         Shares; provided, further, that the portion of the Exercise Price equal
         to the par value of the Shares, if any, must be paid in cash;
 
     (d) by waiver of compensation due or accrued to the Participant for
         services rendered; provided, further, that the portion of the Exercise
         Price equal to the par value of the Shares, if any, must be paid in
         cash;
 
     (e) provided that a public market for the Company's stock exists:
 
          (1) through a "same day sale" commitment from the Participant and a
     broker-dealer that is a member of the National Association of Securities
     Dealers (an "NASD DEALER") whereby the Participant irrevocably elects to
     exercise the Option and to sell a portion of the Shares so purchased to pay
     for the Exercise Price, and whereby the NASD Dealer irrevocably commits
     upon receipt of such Shares to forward the Exercise Price directly to the
     Company; or
 
          (2) through a "margin" commitment from the Participant and a NASD
     Dealer whereby the Participant irrevocably elects to exercise the Option
     and to pledge the Shares so purchased to the NASD Dealer in a margin
     account as security for a loan from the NASD Dealer in the amount of the
     Exercise Price, and whereby the NASD Dealer irrevocably commits upon
     receipt of such Shares to forward the Exercise Price directly to the
     Company; or
 
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     (f) by any combination of the foregoing.
 
     6.2  Loan Guarantees. The Committee may help the Participant pay for Shares
purchased under this Plan by authorizing a guarantee by the Company of a
third-party loan to the Participant.
 
     7. WITHHOLDING TAXES.
 
     7.1  Withholding Generally. Whenever Shares are to be issued in
satisfaction of Options granted under this Plan, the Company may require the
Participant to remit to the Company an amount sufficient to satisfy federal,
state and local withholding tax requirements prior to the delivery of any
certificate or certificates for such Shares. Whenever, under this Plan, payments
in satisfaction of Options are to be made in cash, such payment will be net of
an amount sufficient to satisfy federal, state, and local withholding tax
requirements.
 
     7.2  Stock Withholding. When, under applicable tax laws, a Participant
incurs tax liability in connection with the exercise or vesting of any Option
that is subject to tax withholding and the Participant is obligated to pay the
Company the amount required to be withheld, the Committee may allow the
Participant to satisfy the minimum withholding tax obligation by electing to
have the Company withhold from the Shares to be issued that number of Shares
having a Fair Market Value equal to the minimum amount required to be withheld,
determined on the date that the amount of tax to be withheld is to be
determined. All elections by a Participant to have Shares withheld for this
purpose will be made in writing in a form acceptable to the Committee.
 
     8. PRIVILEGES OF STOCK OWNERSHIP.
 
     8.1  Voting and Dividends. No Participant will have any of the rights of a
stockholder with respect to any Shares until the Shares are issued to the
Participant. After Shares are issued to the Participant, the Participant will be
a stockholder and have all the rights of a stockholder with respect to such
Shares, including the right to vote and receive all dividends or other
distributions made or paid with respect to such Shares; provided, that the
Participant will have no right to retain such stock dividends or stock
distributions with respect to Shares that are repurchased at the Participant's
original Exercise Price pursuant to Section 10.
 
     8.2  Financial Statements. The Company will provide financial statements to
each Participant prior to such Participant's purchase of Shares under this Plan,
and to each Participant annually during the period such Participant has Options
outstanding; provided, however, the Company will not be required to provide such
financial statements to Participants whose services in connection with the
Company assure them access to equivalent information.
 
     9. TRANSFERABILITY. Options granted under this Plan, and any interest
therein, will not be transferable or assignable by Participant, and may not be
made subject to execution, attachment or similar process, otherwise than by will
or by the laws of descent and distribution or as consistent with the specific
Plan and Stock Option Agreement provisions relating thereto. During the lifetime
of the Participant an Option will be exercisable only by the Participant, and
any elections with respect to an Option, may be made only by the Participant.
 
     10. RESTRICTIONS ON SHARES. At the discretion of the Committee, the Company
may reserve to itself and/or its assignee(s) in the Stock Option Agreement a
right to repurchase a portion of or all unvested Shares previously received upon
exercise of an Option and held by a Participant following such Participant's
Termination at any time within ninety (90) days after the later of Participant's
Termination Date and the date Participant purchases Shares under this Plan, for
cash and/or cancellation of purchase money indebtedness, at the Participant's
Exercise Price.
 
     11. CERTIFICATES. All certificates for Shares or other securities delivered
under this Plan will be subject to such stock transfer orders, legends and other
restrictions as the Committee may deem necessary or advisable, including
restrictions under any applicable federal, state or foreign securities law, or
any rules, regulations and other requirements of the SEC or any stock exchange
or automated quotation system upon which the Shares may be listed or quoted.
 
     12. ESCROW; PLEDGE OF SHARES. To enforce any restrictions on a
Participant's Shares, the Committee may require the Participant to deposit all
certificates representing Shares, together with stock powers or other
 
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instruments of transfer approved by the Committee, appropriately endorsed in
blank, with the Company or an agent designated by the Company to hold in escrow
until such restrictions have lapsed or terminated, and the Committee may cause a
legend or legends referencing such restrictions to be placed on the
certificates. Any Participant who is permitted to execute a promissory note as
partial or full consideration for the purchase of Shares under this Plan will be
required to pledge and deposit with the Company all or part of the Shares so
purchased as collateral to secure the payment of Participant's obligation to the
Company under the promissory note; provided, however, that the Committee may
require or accept other or additional forms of collateral to secure the payment
of such obligation and, in any event, the Company will have full recourse
against the Participant under the promissory note notwithstanding any pledge of
the Participant's Shares or other collateral. In connection with any pledge of
the Shares, Participant will be required to execute and deliver a written pledge
agreement in such form as the Committee will from time to time approve. The
Shares purchased with the promissory note may be released from the pledge on a
pro rata basis as the promissory note is paid.
 
     13. EXCHANGE AND BUYOUT OF OPTIONS. The Committee may, at any time or from
time to time, authorize the Company, with the consent of the respective
Participants, to issue new Options in exchange for the surrender and
cancellation of any or all outstanding Options. The Committee may at any time
buy from a Participant an Option previously granted with payment in cash, Shares
or other consideration, based on such terms and conditions as the Committee and
the Participant may agree.
 
     14. SECURITIES LAW AND OTHER REGULATORY COMPLIANCE. An Option will not be
effective unless such Option is in compliance with all applicable federal and
state securities laws, rules and regulations of any governmental body, and the
requirements of any stock exchange or automated quotation system upon which the
Shares may then be listed or quoted, as they are in effect on the date of grant
of the Option and also on the date of exercise or other issuance.
Notwithstanding any other provision in this Plan, the Company will have no
obligation to issue or deliver certificates for Shares under this Plan prior to:
(a) obtaining any approvals from governmental agencies that the Company
determines are necessary or advisable; and/or (b) completion of any registration
or other qualification of such Shares under any state or federal law or ruling
of any governmental body that the Company determines to be necessary or
advisable. The Company will be under no obligation to register the Shares with
the SEC or to effect compliance with the registration, qualification or listing
requirements of any state securities laws, stock exchange or automated quotation
system, and the Company will have no liability for any inability or failure to
do so.
 
     15. NO OBLIGATION TO EMPLOY. Nothing in this Plan or any Option granted
under this Plan will confer or be deemed to confer on any Participant any right
to continue in the employ of, or to continue any other relationship with, the
Company or any Parent, Subsidiary or Affiliate of the Company or limit in any
way the right of the Company or any Parent, Subsidiary or Affiliate of the
Company to terminate Participant's employment or other relationship at any time,
with or without cause.
 
     16. CORPORATE TRANSACTIONS.
 
     16.1  Assumption or Replacement of Options by Successor. In the event of
(a) a dissolution or liquidation of the Company, (b) a merger or consolidation
in which the Company is not the surviving corporation (other than a merger or
consolidation with a wholly-owned subsidiary, a reincorporation of the Company
in a different jurisdiction, or other transaction in which there is no
substantial change in the stockholders of the Company or their relative stock
holdings and the Options granted under this Plan are assumed, converted or
replaced by the successor corporation, which assumption will be binding on all
Participants), (c) a merger in which the Company is the surviving corporation
but after which the stockholders of the Company (other than any stockholder
which merges (or which owns or controls another corporation which merges) with
the Company in such merger) cease to own their shares or other equity interests
in the Company, (d) the sale of substantially all of the assets of the Company,
or (e) any other transaction which qualifies as a "corporate transaction" under
Section 424(a) of the Code wherein the stockholders of the Company give up all
of their equity interest in the Company (except for the acquisition, sale or
transfer of all or substantially all of the outstanding shares of the Company
from or by the stockholders of the Company), any or all outstanding Options may
be assumed, converted or replaced by the successor
 
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corporation (if any), which assumption, conversion or replacement will be
binding on all Participants. In the alternative, the successor corporation may
substitute equivalent Options or provide substantially similar consideration to
Participants as was provided to stockholders (after taking into account the
existing provisions of the Options). The successor corporation may also issue,
in place of outstanding Shares of the Company held by the Participant,
substantially similar shares or other property subject to repurchase
restrictions no less favorable to the Participant. In the event such successor
corporation (if any) refuses to assume or substitute Options, as provided above,
pursuant to a transaction described in this Subsection 16.1, such Options will
expire on such transaction at such time and on such conditions as the Board will
determine.
 
     16.2  Other Treatment of Options. Subject to any greater rights granted to
Participants under the foregoing provisions of this Section 16, in the event of
the occurrence of any transaction described in Section 16.1, any outstanding
Options will be treated as provided in the applicable agreement or plan of
merger, consolidation, dissolution, liquidation, sale of assets or other
"corporate transaction."
 
     16.3  Assumption of Options by the Company. The Company, from time to time,
also may substitute or assume outstanding options granted by another company,
whether in connection with an acquisition of such other company or otherwise, by
either; (a) granting an Option under this Plan in substitution of such other
company's option; or (b) assuming such option as if it had been granted under
this Plan if the terms of such assumed option could be applied to an Option
granted under this Plan. Such substitution or assumption will be permissible if
the holder of the substituted or assumed option would have been eligible to be
granted an Option under this Plan if the other company had applied the rules of
this Plan to such grant. In the event the Company assumes an option granted by
another company, the terms and conditions of such option will remain unchanged
(except that the exercise price and the number and nature of Shares issuable
upon exercise of any such option will be adjusted appropriately pursuant to
Section 424(a) of the Code). In the event the Company elects to grant a new
Option rather than assuming an existing option, such new Option may be granted
with a similarly adjusted Exercise Price.
 
     17. ADOPTION AND EFFECTIVE DATE. This Plan will become effective on the
date that it is adopted by the Board (the "EFFECTIVE DATE").
 
     18. TERM OF PLAN. Unless earlier terminated as provided herein, this Plan
will terminate ten (10) years from the Effective Date.
 
     19. AMENDMENT OR TERMINATION OF PLAN. The Board may at any time terminate
or amend this Plan in any respect, including without limitation amendment of any
form of Stock Option Agreement or instrument to be executed pursuant to this
Plan; provided, however, that no amendments may be made to outstanding Options
without the consent of the Participant.
 
     20. NONEXCLUSIVITY OF THE PLAN. Neither the adoption of this Plan by the
Board nor any provision of this Plan will be construed as creating any
limitations on the power of the Board to adopt such additional compensation
arrangements as it may deem desirable, including, without limitation, the
granting of stock options otherwise than under this Plan, and such arrangements
may be either generally applicable or applicable only in specific cases.
 
     21. DEFINITIONS. As used in this Plan, the following terms will have the
following meanings:
 
     "AFFILIATE" means any corporation that directly, or indirectly through one
or more intermediaries, controls or is controlled by, or is under common control
with, another corporation, where "control" (including the terms "controlled by"
and "under common control with") means the possession, direct or indirect, of
the power to cause the direction of the management and policies of the
corporation, whether through the ownership of voting securities, by contract or
otherwise.
 
     "BOARD" means the Board of Directors of the Company.
 
     "CODE" means the Internal Revenue Code of 1986, as amended.
 
     "COMMITTEE" means the committee appointed by the Board to administer this
Plan, or if no such committee is appointed, the Board.
 
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     "COMPANY" means HNC Software Inc., a corporation organized under the laws
of the State of Delaware, or any successor corporation.
 
     "DISABILITY" means a disability, whether temporary or permanent, partial or
total, within the meaning of Section 22(e)(3) of the Code, as determined by the
Committee.
 
     "EXERCISE PRICE" means the price at which a holder of an Option may
purchase the Shares issuable upon exercise of the Option.
 
     "FAIR MARKET VALUE" means, as of any date, the value of a share of the
Company's Common Stock determined as follows:
 
     (a) if such Common Stock is then quoted on the Nasdaq National Market, its
         closing price on the Nasdaq National Market on the date of
         determination (if such day is a trading day) as reported in The Wall
         Street Journal, and, if such date of determination is not a trading
         day, then on the last trading day prior to the date of determination;
 
     (b) if such Common Stock is publicly traded and is then listed on a
         national securities exchange, its closing price on the last trading day
         prior to the date of determination on the principal national securities
         exchange on which the Common Stock is listed or admitted to trading as
         reported in The Wall Street Journal;
 
     (c) if such Common Stock is publicly traded but is not quoted on the Nasdaq
         National Market nor listed or admitted to trading on a national
         securities exchange, the average of the closing bid and asked prices on
         the last trading day prior to the date of determination as reported in
         The Wall Street Journal; or
 
     (d) if none of the foregoing is applicable, by the Committee in good faith.
 
     "OPTION" means an award of a nonqualified stock option to purchase Shares
pursuant to Section 5.
 
     "PARENT" means any corporation (other than the Company) in an unbroken
chain of corporations ending with the Company, if at the time of the granting of
an Option under this Plan, each of such corporations other than the Company owns
stock possessing 50% or more of the total combined voting power of all classes
of stock in one of the other corporations in such chain.
 
     "PARTICIPANT" means a person who receives an Option under this Plan.
 
     "PLAN" means this HNC Software Inc. 1998 Stock Option Plan, as amended from
time to time.
 
     "SEC" means the Securities and Exchange Commission.
 
     "SHARES" means shares of the Company's Common Stock reserved for issuance
under this Plan, as adjusted pursuant to Sections 2 and 16, and any successor
security.
 
     "STOCK OPTION AGREEMENT" means, with respect to each Option, the signed
written agreement between the Company and the Participant setting forth the
terms and conditions of the Option.
 
     "SUBSIDIARY" means any corporation (other than the Company) in an unbroken
chain of corporations beginning with the Company if, at the time of granting of
the Option, each of the corporations other than the last corporation in the
unbroken chain owns stock possessing 50% or more of the total combined voting
power of all classes of stock in one of the other corporations in such chain.
 
     "TERMINATION" or "TERMINATED" means, for purposes of this Plan with respect
to a Participant, that the Participant has for any reason ceased to provide
services as an employee, officer, consultant, independent contractor or advisor
to the Company or a Parent, Subsidiary or Affiliate of the Company, except in
the case of sick leave, military leave, or any other leave of absence approved
by the Committee, provided that such leave is for a period of not more than
ninety (90) days, or reinstatement upon the expiration of such leave is
guaranteed by contract or statute. The Committee will have sole discretion to
determine whether a Participant has ceased to provide services and the effective
date on which the Participant ceased to provide services (the "TERMINATION
DATE").
 
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