<PAGE>
 
                                                                    EXHIBIT 10.4

                              SIEBEL SYSTEMS, INC.
                      EXECUTIVE DEFERRED COMPENSATION PLAN


                               1.   INTRODUCTION
                                    ------------

1.1  ESTABLISHMENT OF PLAN.  Siebel Systems, Inc. hereby establishes the
     Siebel Systems, Inc. Executive Deferred Compensation Plan effective as of
     January 1, 1997.

1.2  PURPOSE OF PLAN.  Siebel has established this Plan to provide select
     executives with the opportunity to defer the receipt of compensation and a
     vehicle through which to do so.  Siebel intends to maintain the Plan
     primarily for the purpose of providing deferred compensation for a select
     group of management or highly compensated employees, within the meaning
     ERISA Section 401(a)(1).  The Plan will be interpreted in a manner that
     comports with these intentions.


                                2.  DEFINITIONS
                                    -----------
                                        
     Definitions are contained in this article and throughout other sections of
the Plan.  The location of a definition is for convenience only and should not
be given any significance.  A word or term defined in this article (or in any
other article) will have the same meaning throughout the Plan unless the context
clearly requires a different meaning.

2.1    BENEFICIARY means the individual(s) or entity designated by a
       Participant, or by the Plan, to receive any benefit payable upon the
       death of a Participant or Beneficiary.

       A Beneficiary designation must be signed by the Participant and delivered
       to the Benefit Committee on such form as specified by the Benefit
       Committee.  In the absence of a valid or effective Beneficiary
       designation, the Beneficiary will be the Participant's surviving spouse,
       or if there is no surviving spouse, the Participant's estate.

2.2    BENEFIT COMMITTEE means one or more individuals appointed by Siebel
       in accordance with Article VII.  The Benefit Committee will serve as the
       "plan administrator" to manage and control the operation and
       administration of the Plan, within the meaning of ERISA Section 3(16)(A).

2.3    BOARD means the Board of Directors of Siebel Systems, Inc.

2.4    BONUS means the compensation paid in accordance with the Siebel
       Executive Incentive Compensation Plan.

2.5    CODE means the Internal Revenue Code of 1986, as amended from time to
       time.

2.6    EDCP Account means a bookkeeping account established for and
       maintained on behalf of a Participant to which deferred compensation
       amounts, and net income (or losses) thereon, are credited.
  
2.7    ELIGIBLE EMPLOYEE means a common law employee of Siebel identified by
       the Benefit Committee as eligible to defer compensation under the Plan
       for a Plan Year, as listed in Appendix A.  The group of Eligible
       Employees for any Plan Year will be limited to, and may be more
       restrictive than, the group of employees who are members of a select
       group of management or highly compensated employees (within the meaning
       ERISA Section 401(a)(1)).  An employee's eligibility to participate in
       the Plan for a given Plan Year does not guarantee continued eligibility
       to participate in any future Plan Year.
<PAGE>
 
     The CEO will identify the initial group of Eligible Employees in Appendix A
before January 1, 1997 and The Benefit Committee may update Appendix A at any
time.

2.8    ERISA means the Employee Retirement Income Security Act of 1974, as
       amended.

2.9    HARDSHIP means an unforeseeable and unanticipated emergency which is
       caused by an event beyond the control of the Participant or Beneficiary,
       and which would result in severe financial hardship to the Participant or
       Beneficiary if a distribution or revocation of a deferral election were
       not permitted.  Hardship conditions will be evaluated in accordance with
       the terms of Treasury Regulations Section 1.457-2(h)(4).  The Benefit
       Committee will have sole discretion to determine whether a Hardship
       condition exists and the Benefit Committee's determination will be final.

2.10   SIEBEL means Siebel Systems, Inc. and any other subsidiary of
       Siebel Systems, Inc. that is the employer of any Eligible Employee, and
       their respective successors.

2.11   INSOLVENT means Siebel is (a) unable to pay its debts as they
       become due, or (b) subject to a pending proceeding as a debtor
       under the U.S. Bankruptcy Code.

2.12   INVESTMENT FUND OR FUNDS means the investment funds designated by
       Benefit Committee as the basis for determining the investment return to
       be allocated to Participants" EDCP Accounts.  The Benefit Committee may
       change the Investment Funds at such times as it deems appropriate.

2.13   PARTICIPANT means a current or former Eligible Employee who has been
       designated by the Benefit Committee as eligible to participate in the
       Plan and who has an EDCP Account Balance.

2.14   PLAN means the Siebel Systems, Inc. Executive Deferred Compensation
       Plan, as set forth in  this document, as amended form time to time.

2.15   PLAN YEAR means the twelve month period from January 1, 1997 through
       December 31, 1997, and each future calendar year.

2.16   RETIREMENT means termination of employment with Siebel at or after age
       55, or upon termination of employment with Siebel due to Disability.
       Disability means a physical or mental impairment which will apparently be
       permanent or of long and indefinite duration. The Benefit Committee will
       determine whether a Participant is disabled and its determination will be
       final.

2.17   SALARY means a Participant's base salary, quarterly regional performance
       payments and commission payment for a Plan Year, and excludes any other
       form of compensation such as bonuses, proceeds from the exercise of stock
       options of stock appreciate rights, severance payments, moving expenses,
       car or other special allowances, or other amounts included in an Eligible
       Employees' taxable Participant's Salary is determined before taking into
       account any reduction in taxable income by salary reduction under Code
       Section 125 or 401(k), or under this Plan.



                              3.   PARTICIPATION
                                   -------------


3.1    PARTICIPATION.   An Eligible Employee may elect to defer the receipt of
       compensation by completing and submitting a deferred compensation
       agreement on such form and in such
<PAGE>
 
       manner as prescribed by the Benefit Committee. Plan Compensation may be
       deferred through three methods, as follows:

       (a)  BONUS DEFERRAL.  An Eligible Employee can elect to defer all, or 
            any whole percentage or dollar amount, of his or her Bonus paid for
            the Plan Year. The minimum Bonus deferral amount is $5,000.

       (b)  INDEPENDENT SALARY DEFERRAL.  In addition to, or instead of, the 
            automatic rechanneling option described in subsection (c) below, an
            Eligible Employee may elect to defer the receipt of up to 100% of
            Salary to the Plan for a Plan Year. Independent salary deferral
            elections must be made in whole percentage increments.

       (c)  AUTOMATIC RECHANNELING OF 401(K) DEFERRALS.  Effective as of 
            January 1, 1997, a Participant may elect an automatic
            rechanneling of 401(k) deferrals to this Plan. An automatic
            rechanneling election for a Plan Year works in tandem with an
            Eligible Employee's 401(k) election so that an Eligible
            Employee can defer an uninterrupted whole percentage of up to
            15% of Salary through the Siebel Systems, Inc. 401(k) Plan and
            this Plan. Under an automatic rechanneling election, and
            Eligible Employee's 401(k) savings percentage converts to an
            EDCP deferred compensation savings election automatically when
            an Eligible Employee reaches the Code Section 402(g) limit or
            is otherwise limited in making 401(k) deferrals.

    An Eligible Employee's election to defer all or a portion of his or her
Bonus or Salary under any available option is unrelated to any election under
another available option.

3.2    PROCEDURES.  An Eligible Employee must file a written deferred 
       compensation agreement with the Benefit Committee electing the amount of
       Bonus and/or Salary deferrals for the Plan Year and agreeing to have his
       or her Bonus and/or Salary reduced by such amount. A deferred
       compensation agreement must be made on such form and in such manner as
       prescribed by the Benefit Committee to be considered a valid deferred
       compensation election for the Plan Year.

3.3    TIMING OF ELECTIONS.  Any Salary deferral election under Section 3.1 (b),
       and/or (c) must be made before the start of the Plan Year to which the
       Bonus or Salary relates. Any Bonus deferral election under Section 3.1
       (a) must be made before the Bonus is due or ascertainable.

       Notwithstanding anything in this Plan to contrary, in the first Plan 
       Year in which a Participant becomes eligible to participate in the Plan,
       the newly eligible Participant may make an election to defer Salary and
       Bonuses payable during the remainder of such Plan Year. Such election may
       be made with respect to Salary payable for services to be performed
       subsequent to the election within 30 days after the date the Participant
       first becomes eligible. The Benefit Committee may specify such deadlines
       and advance notice requirements as it deems necessary to administer the
       Plan in accordance with this Section.

3.4    IRREVOCABLE ELECTIONS.  In general, deferred compensation agreements 
       for a Plan year are irrevocable and cannot be amended by the Participant.
       In the event of an election under Section 3.1 (c) to automatically
       rechannel 401(k) deferrals, the 401(k) deferral election to which the
       automatic rechannel election relates is also irrevocable for the Plan
       Year.

       However, a Participant may request to revoke a deferred compensation 
       agreement in the event of a Hardship. Such request will be made in
       writing on such form and in such manner as prescribed by the Benefit
       Committee. The Benefit Committee may grant such request if and to the
       extent that it determines that the revocation of the election would serve
       to alleviate the Hardship, in a manner consistent with Section 5.1.
<PAGE>
 
       Siebel reserves the right to modify deferred compensation agreements in 
       any case or class of cases to reflect a change in Plan provisions or for
       administrative convenience.

3.5    COMMUNITY AND MARITAL PROPERTY.  The spouse of a participant may have a
       community or marital property interest in the Participant's EDCP Account
       which the spouse may pass to a third party upon his or her death. If it
       is intended that a spouse relinquish his or her community or marital
       property interest in the Participants EDCP Account, the spouse must
       execute a waiver in which he or she clearly states an intention to
       relinquish his or her rights under community or marital property law with
       respect to the EDCP Account. A spouse's mere consent to a Participant's
       designation of a non-spouse Beneficiary is not sufficient to effect such
       a waiver.


                    4.   SIEBEL SYSTEMS, INC. CONTRIBUTIONS
                         ----------------------------------

4.1    401(K) MATCHING CONTRIBUTIONS.  To the extent that an Eligible Employee's
       matching contributions under the Siebel Systems, Inc. 401(k) Plan are
       limited to satisfy the nondiscrimination requirements of Code Sections
       401(k) and 401(m), Siebel will credit each Eligible Employee's EDCP
       account with a corresponding amount. The credited amount will equal an
       amount which, when considered together with the matching contributions
       made to the Siebel Systems, Inc. 401(k) Plan equal the amount in which
       the Eligible Employee would otherwise be entitled under the terms of the
       Siebel Systems, Inc. 401(k) Plan absent the limitations of Code Sections
       401(k) and 401(m).

4.2    DISCRETIONARY CONTRIBUTIONS.  For any Plan Year, Siebel may also elect to
       credit Eligible Employees' EDCP accounts with such amount (if any) as the
       Benefit Committee (in its discretion) may direct be credited for such
       Plan Year. Such direction will include instructions to determine which
       Eligible Employees are entitled to share in such contributions and the
       method of allocation among such Eligible Employees.


                       5.   PARTICIPANT ACCOUNT BALANCES
                            ----------------------------

5.1    ESTABLISHMENT OF ACCOUNTS.  The Benefit Committee will select an
       independent recordkeeper who will establish and maintain an EDCP Account
       on behalf of each Eligible Employee who elects to participate in the Plan
       or for whom Siebel elects to make a contribution. Contributions and net
       income (or losses) will be credited to such accounts in accordance with
       the provisions of this Article.

5.2    BOOKKEEPING ACCOUNTS.  EDCP Accounts will be primarily for accounting
       purposes and will not restrict the operation of the Plan or require
       separate earmarked assets to be allocated to any account. The
       establishment of an EDCP Account will not give any Participant the right
       to receive any asset held by Siebel in connection with the Plan or
       otherwise.

5.3    CREDITING DEFERRED COMPENSATIONS.  Siebel will credit to a Participant's
       EDCP Account the amount of any Bonus or Salary deferred by the
       Participant as soon as administratively possible following the pay period
       to which such Bonus or Salary would have been paid absent a deferred
       compensation agreement.

5.4    CREDITING SIEBEL CONTRIBUTIONS.  Siebel will credit to a Participant's 
       EDCP Account to amount of any matching or discretionary contributions
       made by Siebel as of the date specified by Siebel.

5.5    ESTABLISHMENT OF INVESTMENT FUNDS.  The Benefit Committee will establish
       one or more Investment Funds which will be maintained for the purpose of
       determining the investment 
<PAGE>
 
       return to be credited to a Participant's EDCP Account. The Committee may
       change the number, identity or composition of the Investment Funds from
       time to time.

       Each Participant will indicate the Investment Funds to which
       contributions under Sections 5.3 and 5.4 and any existing EDCP Account
       balance are to be credited. Investment Fund elections must be made at
       such times and in such manner as the Benefit Committee will specify. A
       Participant may change his or her Investment Fund election periodically
       in such manner as the Benefit Committee may specify.

5.6    CREDITING INVESTMENT RESULTS.  No less frequently than as of the last day
       of each quarter, a Participant's EDCP Account balance will be increased
       or decreased to reflect investment results. EDCP Accounts will be
       credited with the investment return of the Investment Funds in which the
       Participant elected to participate. The credited investment return is
       impounded to reflect the actual performance of the Investment Funds net
       of any investment fees or commissions; however, the Benefit Committee
       reserves the right to calculate the investments return based on the
       Investment Funds' respective rates of return.


                         6.   DISTRIBUTION OF ACCOUNTS
                              ------------------------


6.1    DISTRIBUTIONS IN THE EVENT OF HARDSHIP OR UPON FORFEITURE PENALTY.  Prior
       to a distribution under Sections 6.2 & 6.3 or 6.4, payment of all or a
       portion of a Participant's EDCP Account may be made only in the event of
       Hardship or upon a 10% forfeiture. The amount of any Hardship
       distribution will not exceed the amount required to meet the Hardship,
       including any taxes or penalties due on the distribution. A Participant
       or Beneficiary must submit a written request for a Hardship distribution
       to the Benefit Committee on such form and in such manner as the Benefit
       Committee prescribes, and must certify as to the Hardship condition and
       the severe financial need. The Benefit Committee will have sole
       discretion to determine whether a Hardship exists and to determine the
       appropriate action, if any. In the event of an approved Hardship, a
       Participant will be precluded from deferring compensation for the
       remainder of the Plan Year in which the Hardship occurred and the next
       following Plan Year.

6.2    DISTRIBUTION UPON RETIREMENT OR DISABILITY.   Amounts credited to a
       Participant's EDCP Account will be paid upon Retirement or Disability
       according to the time and manner elected by the Participant. An election
       regarding the time and manner of payment of the Participant's EDCP
       Account balance must be made concurrent with the Participant's election
       to defer compensation under Section 3.1 and cannot subsequently be
       revoked or amended by the Participant, except as provided in Section 6.1.

       (a)  TIME OF PAYMENT.  A Participant's EDCP Account will be paid (or 
            will begin payment) as soon as practicable following a Participant's
            Retirement or Disability, unless the Participant elects to postpone
            such payment for a period of up to 15 months following the
            Participant's termination of employment.

       (b)  MANNER OF PAYMENT.  A Participant's EDCP Account will be paid in a 
            single sum payment unless the Participant has elected to receive the
            distribution of his of her account in 5 substantially equal annual
            installment payment calculated in such method as the Benefit
            Committee prescribes.

6.3    DISTRIBUTION UPON TERMINATION.  The time and manner of distribution of a
       Participant's EDCP Account balance following termination of employment,
       for reasons other than Retirement, Disability or death are governed by
       this Section 6.3.

       (a)  TIME OF PAYMENT.  A Participant's EDCP Account will be paid as soon 
            as practicable following a Participant's termination of employment,
            unless the Participant elects to postpone each payment for a period
            of up to 15 months following the Participant's termination of
            employment.
<PAGE>
 
       (b)  MANNER OF PAYMENT.  Amounts credited to a Participant's EDCP 
            Account will be paid in a single sum payment.

6.4    DISTRIBUTION AT DESIGNATED DATE.  At the time of a Participant's election
       to defer compensation under Section 6.1, a Participant may elect to
       receive a distribution of his or her EDCP Account balance at a specified
       date in the future, provided that such election shall not affect the
       timing of any distribution due to Retirement, Disability or termination
       of employment.

6.5    DISTRIBUTION UPON DEATH.  In the event of the death of a Participant, the
       Participant's Beneficiary will receive the Participant's EDCP Account
       balance in a single sum payment. Any previous election made by the
       Participant regarding installment payments under Section 6.2 will be
       considered null and void. Payment will be made as soon as practicable
       following the Participant's death.

6.6    CASH PAYMENTS ONLY.  All distributions under the Plan will be made in 
       cash by check.



                           7.   PLAN ADMINISTRATION
                                -------------------

7.1    PLAN ADMINISTRATOR.  This Plan will be administered by a Benefit 
       Committee of one or more members, who will be the Plan administrator. The
       Benefit Committee members will be appointed by and serve at the pleasure
       of Compensation Committee of the Board.

7.2    AMENDMENT OR TERMINATION.  The Compensation Committee of the Board may
       amend all or any provision of this Plan, and may terminate the Plan in
       its entirety, at any time and for any reason. No amendment or termination
       of the Plan will reduce any Participant's EDCP Account balance as of the
       effective date of such amendment or termination.

7.3    ADMINISTRATION OF THE PLAN.  The Benefit Committee will have the sole
       discretionary authority to control and mange the operation and
       administration of the Plan and have all powers, authority and discretion
       necessary or appropriate to carry out the Plan provisions, and to
       interpret and apply the terms of the Plan and determine questions of fact
       in the particular cases or circumstances. All decisions, determinations
       and interpretations of the Benefit Committee will be binding on all
       interested parties, subject to the claims and appeal procedure described
       in Section 7.5 and will be given the maximum deference allowed by law.
       The Benefit Committee may delegate in writing its responsibilities as it
       sees fit.

       Committee members who are Participants will abstain from voting on any
       Plan matters that relate primarily to themselves or that would cause them
       to be in constructive receipt of amounts credited to their EDCP Accounts.
       The Compensation Committee of the Board will identify temporary
       replacement of the Benefit Committee in the event that all members must
       abstain from voting.

7.4    INDEMNIFICATION.  Siebel Systems, Inc. will and hereby does indemnify and
       hold harmless any of it s employees, officers, directors or member of the
       Benefit Committee who have fiduciary or administrative responsibilities 
       with respect to the 
<PAGE>
 
       Plan from and against any and all losses, claims, damages, expenses and
       liabilities (including reasonable attorney's fees and amounts paid, with
       the approval of the Board, in settlement of any claim) arising our of or
       resulting from the implementation of a duty, act or decision with respect
       to the Plan, so long as such duty, act or decision does not involve gross
       negligence or willful misconduct on the part of any such individual.



7.5    CLAIMS, INQUIRIES AND APPEALS.

       (a)  Any application for benefits, inquiries about the Plan or inquiries 
            about present or future rights under the Plan must be submitted to
            the Benefit Committee at:

                EDCP Benefit Committee
                Siebel Systems, Inc.
                1855 South Grant Street
                San Mateo,  CA 94115



       (b)  In the event that any application for benefits is denied in whole 
            or in part, the Benefit Committee must notify the applicant, in
            writing, of the denial of the application, and of the applicant's
            right to review the denial. The written notice of denial will be set
            forth in a manner designed to be understood by the individual, and
            will include specific reasons for the denial, specific references to
            the Plan provision upon which the denial is based, a description of
            any information or material that the Benefit Committee needs to
            complete the review and an explanation of the Plan's review
            procedure.

            This written notice will be given to the individual within 90 days
            after the Benefit Committee receives the application, unless special
            circumstances require an extension of time, in which case, the
            Benefit Committee has up to an additional 90 days for processing the
            application. If an extension of time for processing is required,
            written notice of the extension will be furnished to the applicant
            before the end of the initial 90-day period.

            This notice of extension will describe the special circumstances
            necessitating the additional time and the date by which the Benefit
            Committee is to render its decision on the application. If written
            notice of denial of the application for benefits is not furnished
            within the specified time, the application shall be deemed to be
            denied. The applicant will then be permitted to appeal the denial in
            accordance with the review procedure described below.

       (c)  Any person (or the person's authorized representative) for whom an
            application for benefits is denied (or deemed denied), in whole or
            in part, may appeal the denial by submitting a request for a review
            to the Benefit Committee within 60 days after the application is
            denied (or deemed denied). The Benefit Committee will give the
            applicant (or his or her 
<PAGE>
 
            representative) an opportunity to review pertinent documents in
            preparing a request for a review. A request for a review shall be in
            writing and shall be addressed to:

                EDCP Benefit Committee/Appeals
                Siebel Systems, Inc.
                1855 South Grant Street
                San Mateo,  CA  94115


       A request for review must set forth all of the grounds on which it is
       based, all facts in support of the request and any other matters that the
       applicant feels are pertinent. The Benefit Committee may require the
       applicant to submit additional facts, documents or other material as it
       may find necessary or appropriate in making its review.

       (d)  The Benefit Committee will act on each request for review within 
            60 days after receipt of the request, unless special circumstances
            require an extension of time (not to exceed an additional 60 days),
            for processing the request for a review. If an extension for review
            is required, written notice of the extension will be furnished to
            the applicant within the initial 60-day period. The Benefit
            Committee will give prompt, written notice of its decision to the
            applicant. In the event that the Benefit Committee confirms the
            denial of the application for benefits in whole or in part, the
            notice will outline, in a manner calculated to be understood by the
            applicant, the specific Plan provisions upon which the decision is
            based. If written notice of the Benefit Committee's decision is not
            given to the applicant within the time prescribed in this Subsection
            (d), the application will be deemed denied on review.

       (e)  The Benefit Committee will establish rules and procedures, 
            consistent with the Plan and with ERISA, as may be necessary and
            appropriate in carrying out its responsibilities in reviewing
            benefit claims. The Benefit Committee may require an applicant who
            wishes to submit additional information in connection with an appeal
            from the denial (or deemed denial) of benefits to do so at the
            applicant's own expense.

       (f)  No legal action for benefits under the Plan may be brought until the
            claimant (i) has submitted a written application for benefits in
            accordance with the procedures described by Sections 7.5(a) above,
            (ii) has been notified by the Benefit Committee that the application
            is denied (or the application in accordance with the appeal
            procedure described in Section 7.5 (c) above and (iv) has been
            notified in writing that the Benefit Committee has denied the appeal
            (or the appeal is deemed to be denied due to the Benefit Committee's
            failure to take any action on the claim within the time prescribed
            by Section 7.5 (d) above).


                              8.   MISCELLANEOUS
                                   -------------

8.1    FUNDING.  Participant deferrals pursuant to Article 3 and Siebel
       Contributions pursuant to Article 4, and any earnings therein, will be
       held in trust by an independent third party trustee selected by the
       Compensation committee of the Board, and as such are earmarked to pay
       benefits under the terms of the Plan. The Benefit Committee will direct
       Siebel to make 
<PAGE>
 
       periodic contributions to the trust at such times and in such amounts as
       the Benefit Committee deems appropriate.

       Trust assets can not be diverted to, or used for, any other purpose
       except payments to Participants and Beneficiaries under the terms of the
       Plan or, if Siebel is Insolvent, to Siebel's creditors. Participants and
       Beneficiaries will have no right against Siebel with respect to the
       payment of any portion of the Participant's EDCP Account, except as a
       general unsecured creditor of Siebel.

8.2    NONALIENATION. No benefit or interest of any Participant of Beneficiary
       under this Plan will be subject to any manner of assignment, alienation,
       anticipation, sale transfer, pledge or encumbrance, whether voluntary or
       involuntary. However, the Benefit Committee will honor a court order
       regarding the payment of alimony or other support payments, or the
       establishment of community property or other marital property rights, to
       the extent required by law. Prior to distribution to a Participant or
       Beneficiary, no EDCP Account balance will be in any manner subject to the
       debts, contracts, liabilities, engagements or torts of the Participant
       for Beneficiary. Assets held in trust to fund this Plan may, however, be
       diverted to pay Siebel creditors, if Siebel is Insolvent.

8.3    LIMITATION OF RIGHTS.  Nothing in this Plan will be construed to give a
       Participant the right to continue in the employ of Siebel Systems, Inc.
       at any particular position or to interfere with the right of Siebel to
       discharge, lay off or discipline a Participant at any time and for any
       reason, or to give Siebel the right to require any Participant to remain
       in its employ or to interfere with the Participant's right to terminate
       his employment.

       The fact that a participant is designated as an Eligible Employee who is
       eligible to defer compensation for a given Plan Year will not in any way
       assure his or her continued eligibility to defer compensation for any
       subsequent Plan Year.

8.4    GOVERNING LAW.  To the extent that state law applies, the provisions of
       this Plan will be construed, enforced and administered in accordance with
       the laws of the State of California, except to the extent preempted by
       ERISA.

    IN WITNESS WHEREOF, by its duly authorized officer, Siebel Systems, Inc. has
executed this Plan on the date indicated below.

Siebel Systems, Inc.
<PAGE>
 
                     EXECUTIVE DEFERRED COMPENSATION PLAN


                                  Appendix A

    For the 1997 Plan Year, the following select group of management or highly
compensated employees will be eligible to participate in the Siebel Systems,
Inc. Executive Deferred Compensation Plan:


    All Vice Presidents, Senior Vice Presidents, Executive Vice Presidents, and
the Chief Executive Officer of Siebel Systems, Incorporated.