
<PAGE>
 
                                 EXHIBIT 99(b)

             COMPUSA INC. DEFERRED COMPENSATION TRUST (AS AMENDED)
<PAGE>
 
                                  COMPUSA INC.
                          DEFERRED COMPENSATION TRUST
               (Amended and Restated Effective November 1, 1995)

     This Agreement (the "Trust Agreement") is made and entered into as of
November 1, 1995, by and between CompUSA Inc. ("CompUSA") and Wells Fargo Bank,
N.A. (the "Trustee").  This Trust Agreement amends and restates, in its
entirety, the previous trust agreement entered into as of November 1, 1995, by
and between CompUSA and Trustee.


                                R E C I T A L S:

     A.  CompUSA has adopted the CompUSA Inc. Deferred Compensation Plan (the
"Plan"), a non-qualified deferred compensation plan which benefits a select
group of management and highly compensated employees of CompUSA and its
subsidiaries and affiliates (collectively referred to in this Plan as the
"Company").

     B.  Company has incurred or expects to incur liability under the terms of
the Plan with respect to the individuals participating in the Plan.

     C.  Company wishes to establish a trust (the "Trust") and to contribute to
the Trust assets that shall be held therein, subject to the claims of Company's
creditors in the event of Company's Insolvency, as herein defined, until paid to
Plan participants and their beneficiaries in such manner and at such times as
specified in the Plan.

     D.  It is the intention of the parties that the Trust shall constitute an
unfunded arrangement and shall not affect the status of the Plan as an unfunded
plan maintained for the purpose of providing deferred compensation for a select
group of management or highly compensated employees for purposes of Title I of
the Employee Retirement Income Security Act of 1974.

     E.  It is the intention of Company to make contributions to the Trust to
provide itself with a source of funds to assist it in the meeting of its
liabilities under the Plan.

     NOW, THEREFORE, the parties establish the Trust and agree that the Trust
shall be comprised, held and disposed of as follows:

SECTION 1.  ESTABLISHMENT OF TRUST.

     (a) Company hereby deposits with Trustee in trust $100 which shall become
the principal of the Trust to be held, administered and disposed of by Trustee
as provided in this Trust Agreement.

     (b) The Trust hereby established shall be irrevocable.

     (c) The Trust is intended to be a grantor trust, of which Company is the
grantor, within the meaning of subpart E, part I, subchapter J, chapter 1,
subtitle A of the Internal Revenue Code of 1986, as amended (the "Code"), and
shall be construed accordingly.
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     (d) The principal of the Trust and any earnings thereon shall be held
separate and apart from other funds of Company and shall be used exclusively for
the uses and purposes of Plan participants and general creditors as herein set
forth.  Plan participants and their beneficiaries shall have no preferred claim
on, or any beneficial ownership interest in, any assets of the Trust.  Any
rights created under the Plan and this Trust Agreement shall be mere unsecured
contractual rights of Plan participants and their beneficiaries against Company.
Any assets held by the Trust will be subject to the claims of Company's general
creditors under federal and state law in the event of Insolvency, as defined in
Section 3(a) hereof.

SECTION 2.  PAYMENTS TO PLAN PARTICIPANTS AND THEIR BENEFICIARIES.

     (a) Company shall direct the Plan recordkeeper to deliver to Trustee a
schedule (the "Payment Schedule") that indicates the amounts payable in respect
of each Plan participant (and each participant's beneficiaries), that provides a
formula or other instructions acceptable to Trustee for determining the amounts
so payable, the form in which such amounts are to be paid (as provided for or
available under the Plan) and the time of commencement for payment of such
amounts.  Except as otherwise provided herein, Trustee shall make payments to
the Plan participants and their beneficiaries in accordance with the Payment
Schedule.  The Trustee shall make provision for the reporting and withholding of
any federal, state or local taxes that may be required to be withheld with
respect to the terms of the Plan and shall pay amounts withheld to the
appropriate taxing authorities or determine that such amounts have been
reported, withheld and paid by Company.

     (b) The entitlement of a Plan participant or participant's beneficiaries to
benefits under the Plan shall be determined by Company or such party as it shall
designate under the Plan, and any claim for such benefits shall be considered
and reviewed under the procedures set out in the Plan.

     (c) Company may make payments of benefits directly to Plan participants or
their beneficiaries as they become due under the terms of the Plan.  Company
shall notify Trustee of its decision to make payment of benefits directly prior
to the time amounts are payable to participants or their beneficiaries.  In
addition, if the principal of the Trust, and any earnings thereon, are not
sufficient to make payments of benefits in accordance with the terms of the
Plan, Company shall make the balance of each such payment as it falls due.
Trustee shall notify Company where principal and earnings are not sufficient.

     (d) Following a Change in Control, Trustee shall obtain the Payment
Schedule referenced in (a) above directly from the Plan recordkeeper, who is
designated as such immediately prior to the Change in Control.  Trustee may rely
on an opinion of counsel selected by Trustee that a Change in Control has
occurred for purposes of this Trust Agreement.  If the Payment Schedule provided
to Trustee by the Plan recordkeeper indicates that payment of benefits to a
participant is conditioned upon a participant's termination of employment from
the Company, Trustee shall be entitled to rely on an affidavit of termination
executed by the participant or the participant's beneficiary in a form
acceptable to the Trustee as evidence that termination of employment has
occurred.

                                       2
<PAGE>
 
SECTION 3.  TRUSTEE RESPONSIBILITY REGARDING PAYMENTS TO TRUST BENEFICIARY WHEN
            COMPANY IS INSOLVENT.

     (a) Trustee shall cease payment of benefits to Plan participants and their
beneficiaries if Company is Insolvent.  Company shall be considered "Insolvent"
for purposes of this Trust Agreement if (i) Company is unable to pay its debts
as they become due, or (ii) Company is subject to a pending proceeding as a
debtor under the United States Bankruptcy Code.

     (b) At all times during the continuance of the Trust, as provided in
Section 1(d) hereof, the principal and income of the Trust shall be subject to
claims of general creditors of Company under federal and state laws as set forth
below.

          (1) The Board of Directors and the Chief Executive Officer of Company
     shall have the duty to inform Trustee in writing of Company's Insolvency.
     If a person claiming to be a creditor of Company alleges in writing to
     Trustee that Company has become Insolvent, Trustee shall determine whether
     Company is Insolvent and, pending such determination, Trustee shall
     discontinue payment of benefits to Plan participants and their
     beneficiaries.

          (2) Unless Trustee has actual knowledge of Company's Insolvency or has
     received notice from Company of a person claiming to be a creditor alleging
     that Company is Insolvent, Trustee shall have no duty to inquire whether
     Company is Insolvent.  Trustee may in all events rely on such evidence
     concerning Company's solvency as may be furnished to Trustee and that
     provides Trustee with a reasonable basis for making a determination
     concerning Company's solvency.

          (3) If at any time Trustee has determined that Company is Insolvent,
     Trustee shall discontinue payment to Plan participants and their
     beneficiaries and shall hold the assets of the Trust for the benefit of
     Company's general creditors.  Nothing in this Trust Agreement shall in any
     way diminish any rights of Plan participants and their beneficiaries to
     pursue their rights as general creditors of Company with respect to
     benefits due under the Plan or otherwise.

          (4) Trustee shall resume the payment of benefits to Plan participants
     and their beneficiaries in accordance with Section 2 of this Trust
     Agreement only after Trustee has determined that Company is not Insolvent
     (or is no longer Insolvent).

     (c) Provided that there are sufficient assets in the Trust, if Trustee
discontinues the payment of benefits from the Trust pursuant to Section 3(b)
hereof and subsequently resumes such payments, the first payment following such
discontinuance shall include the aggregate amount of all payments due to Plan
participants and their beneficiaries under the terms of the Plan for the period
of such discontinuance, less the aggregate amount of any payments made to Plan
participants and their beneficiaries by Company in lieu of the payments provided
for hereunder during any such period of discontinuance.

                                       3
<PAGE>
 
SECTION 4.  PAYMENTS TO COMPANY.

     Except as provided in Section 3 hereof, Company shall have no right or
power to direct Trustee to return to Company or to divert to others any of the
Trust assets before all payments of benefits have been made to Plan participants
and their beneficiaries pursuant to the terms of the Plan, except for the annual
transfer of assets to the CompSavings Plan for Employees of CompUSA Inc.
pursuant to the terms of the Plan.

SECTION 5.  INVESTMENT AUTHORITY.

     (a) Trustee may invest in securities (including stock or rights to acquire
stock) or obligations issued by CompUSA.  All rights associated with assets of
the Trust shall be exercised by Trustee or the person designated by Trustee and
shall in no event be exercisable by or rest with Plan participants except that
voting rights with respect to Trust assets will be exercised by Company.
Company shall have the right at any time and from time to time, in its sole
discretion, to substitute assets of equal fair market value for any asset held
by the Trust.  This right is exercisable by Company in a nonfiduciary capacity
without the approval or consent of any person in a fiduciary capacity.

     (b) Except as provided below, Company shall have all power over and
responsibility for the management, disposition and investment of Trust assets,
and Trustee shall comply with proper written directions of Company concerning
the Trust assets.  Company shall not issue directions in violation of the terms
of this Trust Agreement.  Except as provided in this Trust Agreement, Trustee
shall have no duty or responsibility to review, initiate action or make
recommendations regarding Trust assets and shall retain assets until directed in
writing by Company to dispose of them.

     (c) Company may appoint an investment manager or managers to direct,
control or manage the investment of all or a portion of the Trust assets.
Company shall notify Trustee in writing of the appointment of each investment
manager and the portion of the Trust assets subject to the investment manager's
direction.  If the foregoing conditions are met, the investment manager shall
have the power to manage, acquire, retain or dispose of such portion, and
Trustee shall not be liable for the acts or omissions of the investment manager
or be under an obligation to invest or otherwise manage the portion of the Trust
assets which is subject to the direction of such investment manager.

     (d) Company may also delegate all of its investment authority to Trustee
for all or part of the Trust.  Upon written acceptance of that delegation,
Trustee shall have full power and authority to invest and reinvest the portion
of the Trust so designated by Company in investments of any kind.

     (e) The Trust may hold assets of any kind, including shares of any
registered investment company, whether or not Trustee or any of its affiliates
is an advisor to, or other service provider to, such company and receives
compensation from such company for the services provided.

                                       4
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     (f) The Trust may hold that portion of the Trust Fund as is appropriate,
for the ordinary administration and for the disbursement of funds in cash,
without liability for interest, by depositing the same in any bank (including
deposits which bear a reasonable rate of interest in a bank or similar financial
institution supervised by the United States or a State, even where a bank or
financial institution is Trustee, or is otherwise a fiduciary of the Plan,
including Wells Fargo Bank, National Association), subject to the rules and
regulations governing such deposits, and without regard to the amount of such
deposit.

SECTION 6.  DISPOSITION OF INCOME.

     During the term of the Trust, all income received by the Trust, net of
expenses and taxes, shall be accumulated and reinvested.

SECTION 7.  ACCOUNTING BY TRUSTEE.

     Trustee shall keep accurate and detailed records of all investments,
receipts, disbursements and all other transactions in Trust assets required to
be made, including such specific records as shall be agreed upon in writing
between Company and Trustee.  Within 90 days following the close of each
calendar year and within 90 days after the removal or resignation of Trustee,
Trustee shall deliver to Company a written account of its administration of the
Trust during such year or during the period from the close of the last preceding
year to the date of such removal or resignation setting forth all investments,
receipts, disbursements and other transactions effected by it, including a
description of all securities and investments purchased and sold, with the cost
or net proceeds of such purchases or sales (accrued interest paid or receivable
being shown separately) and showing all cash, securities and other property held
in the Trust at the end of such year or as of the date of such removal or
resignation as the case may be.

SECTION 8.  RESPONSIBILITY OF TRUSTEE.

     (a) Trustee shall act with the care, skill, prudence and diligence under
the circumstances then prevailing that a prudent person acting in like capacity
and familiar with such matters would use in the conduct of an enterprise of a
like character and with like aims; provided that Trustee shall incur no
liability to any person for any action taken pursuant to a direction, request or
approval given by Company which is contemplated by, and in conformity with, the
terms of the Plan or this Trust Agreement and is given in writing by Company.
In the event of a dispute between Company and a party, Trustee may apply to a
court of competent jurisdiction to resolve the dispute.

     (b) If Trustee undertakes or defends any litigation arising in connection
with the Trust, Company agrees to indemnify Trustee against Trustee's costs,
expenses and liabilities (including without limitation attorneys' fees and
expenses) relating thereto and to be primarily liable for such payments.  If
Company does not pay such costs, expenses and liabilities in a reasonably timely
manner, Trustee may obtain payment from the Trust.

     (c) Trustee may consult with legal counsel (who may also be counsel for
Company generally) with respect to any of its duties or obligations hereunder.

                                       5
<PAGE>
 
     (d) Trustee may hire agents, accountants, actuaries, investment advisors,
financial consultants or other professionals to assist in it performing any of
its duties or obligations hereunder.

     (e) Trustee shall have, without exclusion, all powers conferred on trustees
by applicable law unless expressly provided otherwise herein; provided that if
an insurance policy is held as an asset of the Trust, Trustee shall have no
power to name a beneficiary of the policy other than the Trust, to assign the
policy (as distinct from conversion of the policy to a different form) other
than to a successor trustee or to loan to any person the proceeds of any
borrowing against such policy.

     (f) Notwithstanding any powers granted to Trustee pursuant to this Trust
Agreement or to applicable law, Trustee shall not have any power that could give
the Trust the objective of carrying on a business and dividing the gains
therefrom within the meaning of Section 301.7701-2 of the Procedure and
Administrative Regulations promulgated pursuant to the Code.

SECTION 9.  COMPENSATION AND EXPENSES OF TRUSTEE.

     Company shall pay all administrative and Trustee's fees and expenses.  If
not so paid, the fees and expenses shall be paid from the Trust.

SECTION 10.  RESIGNATION AND REMOVAL OF TRUSTEE.

     (a) Trustee may resign at any time by written notice to Company, which
shall be effective 90 days after receipt of such notice unless Company and
Trustee agree otherwise.

     (b) Trustee may be removed by Company on 90 days notice or upon shorter
notice accepted by Trustee.

     (c) Upon resignation or removal of Trustee and appointment of a successor
trustee, all assets shall subsequently be transferred to a successor trustee.
The transfer shall be completed within 90 days after receipt of notice of
resignation, removal or transfer unless Company extends the time limit.

     (d) If Trustee resigns or is removed, a successor shall be appointed in
accordance with Section 11 hereof by the effective date of resignation or
removal under paragraph (a) or (b) of this section.  If no such appointment has
been made, Trustee may apply to a court of competent jurisdiction for
appointment of a successor or for instructions.  All expenses of Trustee in
connection with the proceeding shall be allowed as administrative expenses of
the Trust.

     (e) If Trustee resigns or is removed within two years after a Change in
Control, Trustee shall select a successor trustee in accordance with the
provisions of Section 11(b) hereof prior to the effective date of Trustee's
resignation or removal.

                                       6
<PAGE>
 
SECTION 11.  APPOINTMENT OF SUCCESSOR.

     (a) If Trustee resigns or is removed in accordance with Section 10(a) or
(b) hereof, Company may appoint any third party, such as a bank trust department
or other party that may be granted corporate trustee powers under state law, as
a successor to replace Trustee upon resignation or removal.  The appointment
shall be effective when accepted in writing by the new trustee who shall have
all of the rights and powers of the former Trustee including ownership rights in
the Trust assets.  The former Trustee shall execute any instrument necessary or
reasonably requested by Company or the successor trustee to evidence the
transfer.

     (b) If Trustee resigns or is removed pursuant to the provisions of Section
10(e) hereof and selects a successor trustee, Trustee may appoint any third
party such as a bank trust department or other party that may be granted
corporate trustee powers under state law as a successor trustee.   The
appointment of a successor trustee shall be effective when accepted in writing
by the new trustee.  The new trustee shall have all the rights and powers of the
former Trustee including ownership rights in Trust assets.  The former Trustee
shall execute any instrument necessary or reasonably requested by the successor
trustee to evidence the transfer.

     (c) The successor trustee need not examine the records and acts of any
prior Trustee and may retain or dispose of existing Trust assets subject to
Sections 7 and 8 hereof.  The successor trustee shall not be responsible for and
Company shall indemnify and defend the successor trustee from any claim or
liability resulting from any action or inaction of any prior Trustee or from any
other past event or any condition existing at the time it becomes successor
trustee.

SECTION 12.  AMENDMENT OR TERMINATION.

     (a) This Trust Agreement may be amended by a written instrument executed by
Trustee and Company.  Notwithstanding the foregoing, no such amendment shall
conflict with the terms of the Plan or shall make the Trust revocable after it
has become irrevocable in accordance with Section 1(b) hereof.

     (b) The Trust shall not terminate until the date on which Plan participants
and their beneficiaries are no longer entitled to benefits pursuant to the terms
of the Plan.  Upon termination of the Trust, any assets remaining in the Trust
shall be returned to Company.

SECTION 13.  MISCELLANEOUS.

     (a) Any provision of this Trust Agreement prohibited by law shall be
ineffective to the extent of any such prohibition without invalidating the
remaining provisions hereof.

     (b) Benefits payable to Plan participants and their beneficiaries from the
Trust may not be anticipated, assigned (either at law or in equity), alienated,
pledged, encumbered or subjected to attachment, garnishment, levy, execution or
other legal or equitable process.

     (c) The Trust shall be governed by the laws of California, and this Trust
Agreement shall be construed in accordance with the laws of California.

                                       7
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     (d) For purposes of this Trust Agreement, a Change in Control will be
deemed to have occurred in the event any Person (other than a Person meeting the
requirements of clauses (i) and (ii) of Rule 13d-1(b)(1) or its successors
promulgated under the Securities Exchange Act of 1934, as amended) meets the
requirements for becoming an Acquiring Person, whether or not a Distribution
Date occurs or the Rights are redeemed by CompUSA, as those terms are defined in
the Rights Agreement between CompUSA and Bank One, Texas, N.A., dated as of
April 29, 1994.

     (e) Each company participating in the Plan other than CompUSA is a
participating employer.  By adopting the Plan and Trust Agreement, each
participating employer agrees to all of the terms of the Trust Agreement and
further agrees that CompUSA (or its delegate) shall have the exclusive authority
as the "Company" for purposes of the provisions of this Trust Agreement
respecting the administration, interpretation and amendment of this Trust
Agreement.  Each such participating employer may terminate its participation in
the Trust at any time.

SECTION 14.  EFFECTIVE DATE.

     The effective date of the Trust and this Trust Agreement shall be
 November 1, 1995.


Wells Fargo Bank, N.A.                    CompUSA Inc.



By  /s/ Jane McKeever                     By  /s/ Mel McCall
  --------------------------                -------------------------- 



By  /s/ Kathryn R. Reid
  --------------------------            

 

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