<PAGE>

                                                                    EXHIBIT 10.6

                Original Plan approved by the Compensation Committee on 11/15/96

        This Amended and Restated Plan approved and ratified by the Compensation
                                                            Committee on 3/22/04

  This Amended and Restated Plan approved and ratified by the Board of Directors
                                                                      on 3/23/04

     This Amended and Restated Plan approved and ratified by the Stockholders on
                                                                         5/18/04
























                              COMERICA INCORPORATED

                              AMENDED AND RESTATED

                             EMPLOYEE STOCK PURCHASE

                                      PLAN

<PAGE>

                              COMERICA INCORPORATED
                              AMENDED AND RESTATED
                          EMPLOYEE STOCK PURCHASE PLAN

                                TABLE OF CONTENTS

<TABLE>
<S>                                                                        <C>
SECTION I - PURPOSE.....................................................    1

SECTION II - DEFINITIONS................................................    1

SECTION III - INTRODUCTION..............................................    4

SECTION IV - PARTICIPATION..............................................    5

SECTION V - CONTRIBUTIONS...............................................    6

SECTION VI - ACQUISITION OF CORPORATION SHARES..........................    9

SECTION VII - RIGHTS WITH RESPECT TO SHARES HELD IN PLAN................    9

SECTION VIII - WITHDRAWALS FROM PLAN....................................    9

SECTION IX - MISCELLANEOUS PROVISIONS...................................   10

SECTION X - EFFECTIVE DATE OF PLAN......................................   12
</TABLE>
<PAGE>

SECTION I - PURPOSE

      The Board of Directors of Comerica Incorporated (the "Corporation")
believes that the interests of the Corporation are served through share
ownership of the Corporation by its employees. Such ownership strengthens the
sense of identity between the Corporation and its employees and furthers a unity
of purpose among the Corporation, its employees and its stockholders. It is the
purpose of this Comerica Incorporated Amended and Restated Employee Stock
Purchase Plan to provide a convenient means through which employees of the
Corporation and its subsidiaries and affiliates may acquire shares in the
Corporation.

SECTION II - DEFINITIONS

      Whenever used in the Plan, the following terms shall have the meanings set
forth below.

      A.    "Account" means an account established for each Participant under
            the Plan to hold Corporation Shares acquired for the Participant's
            account with Payroll Withholding Contributions, Other Permitted
            Contributions, Service Award Contributions, Matching Contributions,
            Share Retention Contributions and/or Reinvested Cash Dividends.

      B.    "Beneficiary(ies)" means the individual(s) to whom the balance of
            the Participant's Account is to be distributed in the event assets
            remain in such Account at the time of the Participant's death, or by
            whom any rights of the Participant, after the Participant's death,
            may be exercised.

      C.    "Beneficiary Designation Form" means the form used to designate the
            Participant's Beneficiary(ies), as such form may be modified by the
            Committee or the Plan Administrator from time to time.

      D.    "Bi-Weekly Base Pay" means the gross amount of cash compensation a
            Participant receives during each bi-weekly pay period, including,
            without limitation, base pay, incentive compensation paid through
            the Management Incentive Plan, or through a specific business unit
            incentive plan, referral awards, ROAR payments, overtime, shift
            differential and commissions, lump sum merit bonuses (effective as
            of January 22, 1999) and/or such other payments as the Committee or
            the Plan Administrator may determine appropriate from time to time
            for such purposes. Bi-Weekly Base Pay shall not include any amount
            which is deferred under the Deferred Compensation Plan(s).

      E.    "Board" means the Board of Directors of Comerica Incorporated.

                                       1
<PAGE>

       F.   "Code" means the Internal Revenue Code of 1986, as amended. All
            references to sections of the Code shall be deemed to refer to any
            successor provisions to such sections.

       G.   "Committee" means the committee appointed by the Board to administer
            the Plan as provided herein. Unless otherwise determined by the
            Board, the Compensation Committee of the Board shall be the
            Committee.

       H.   "Corporation" means Comerica Incorporated, a Delaware corporation.
            For purposes of Plan provisions relating to eligibility to
            participate or receive or make contributions, it shall also include
            subsidiaries and affiliates of the Corporation.

       I.   "Corporation Shares" means shares of $5.00 par value common stock of
            the Corporation.

       J.   "Custodian Bank" means Comerica Bank, a Michigan banking
            corporation, or such other institution as may be appointed by the
            Corporation to hold Corporation Shares in Accounts of Participants
            under the Plan.

       K.   "Deferred Compensation Plan(s)" means the 1999 Comerica Incorporated
            Deferred Compensation Plan, together with any and all amendments,
            restatements and/or modifications thereof, and/or the 1999 Comerica
            Incorporated Amended and Restated Common Stock Deferred Incentive
            Award Plan, together with any and all amendments, restatements
            and/or modifications thereof, or any plan adopted by the Corporation
            as a successor to the foregoing.

       L.   "Disability" has the meaning set forth in Section V(D) hereof.

       M.   "Employee" means an individual who renders service to the
            Corporation or one of its subsidiaries or affiliates as a common law
            employee or officer.

       N.   "Exchange Act" means the Securities Exchange Act of 1934, as
            amended.

       O.   "Management Incentive Plan" means the Amended and Restated Comerica
            Incorporated Management Incentive Plan, together with any and all
            amendments, restatements and/or modifications thereof, or any plan
            adopted by the Corporation as a successor to the foregoing.

       P.   "Matching Contribution" means, subject to the limitations of Section
            V(C) hereof, a contribution by the Corporation, the gross amount of
            which shall equal 15% of the aggregate amount of Payroll Withholding
            Contributions, Service Award Contributions and/or Other Permitted
            Contributions made during the previous

                                       2
<PAGE>

            quarter. The Matching Contribution, net of all applicable
            withholding and deductions, shall be used to purchase Corporation
            Shares.

       Q.   "Other Permitted Contribution" means a non-periodic contribution of
            a Participant to the Plan pursuant to guidelines approved by the
            Committee or the Plan Administrator from time to time.

       R.   "Participant" means an Employee or former Employee who has an
            Account under the Plan.

       S.   "Payroll Withholding Contribution" means a contribution of a
            Participant under the Plan equal to the percentage of the
            Participant's gross Bi-Weekly Base Pay such Participant has elected
            to contribute to the Plan; provided, however, that in the event the
            Participant's pay, less all applicable withholding and deductions,
            is less than the amount of his or her elected contribution, the
            contribution shall be reduced so as not to exceed 100% of the
            Participant's net pay. Payroll Withholding Contributions shall be
            withheld by the Corporation and forwarded to the Custodian Bank,
            which shall utilize such contributions to purchase Corporation
            Shares for allocation to the Employee's Account in accordance with
            the provisions of the Plan.

       T.   "Plan" means the Comerica Incorporated Amended and Restated Employee
            Stock Purchase Plan, as set forth herein and as hereinafter amended
            and/or restated from time to time.

       U.   "Plan Administrator" means, unless determined otherwise by the Board
            or the Committee, the Director of Corporate Human Resources (or, if
            no individual is the Director of Corporate Human Resources, then the
            designated acting Director of Corporate Human Resources).

       V.   "Plan Year" means the fiscal year on which the records of the Plan
            are kept, which shall be the calendar year; provided, however, that
            the first Plan Year shall be the period commencing April 1, 1997 and
            ending December 31, 1997.

       W.   "Reinvested Cash Dividends" means cash dividends paid on Corporation
            Shares allocated to a Participant's Account which are utilized to
            purchase additional Corporation Shares for such Participant's
            Account.

       X.   "Retirement" has the meaning set forth in Section V(D) hereof.

       Y.   "Section 16 Insider" means any Participant who is designated by the
            Corporation as a reporting person under Section 16 of the Exchange
            Act.

                                       3
<PAGE>

       Z.   "Service Award" means a discretionary award, in the form of a
            Service Award Contribution, made by the Corporation in recognition
            of an Employee's service to the Corporation.

      AA.   "Service Award Contribution" means a discretionary contribution by
            the Corporation to be allocated to a Participant's Account in
            recognition of an Employee's service to the Corporation. The Service
            Award Contribution, net of any applicable withholding and
            deductions, shall be used to purchase Corporation Shares.

      BB.   "Share Retention Contribution" means, subject to fulfillment of the
            requirements in Section V(D) hereof, a contribution by the
            Corporation to be allocated to a Participant's Account in a Plan
            Year equal to 5% of the amount of Payroll Withholding Contributions,
            Service Award Contributions and/or Other Permitted Contributions
            made to such Participant's Account in the first of the two
            immediately preceding Plan Years as set forth in Section V(D). Share
            Retention Contributions shall be utilized to purchase additional
            Corporation Shares for the Participant's Account.

      CC.   "Two-Plan-Year-Period" means the two Plan Years immediately
            preceding the Plan Year in which a Share Retention Contribution is
            made.

SECTION III - INTRODUCTION

      A. Administration. The Plan shall be administered by the Committee;
provided, however, that the Board shall have the authority to exercise any and
all duties and responsibilities assigned to the Committee under the Plan. The
Committee may delegate all or any portion of its responsibilities and powers to
any one or more of its members and may delegate all or any part of its
responsibilities and powers to any person or persons selected by it, including,
without limitation, the Plan Administrator. In addition, unless determined
otherwise by the Board or Committee, the Plan Administrator shall handle the
day-to-day administration of the Plan. The Plan Administrator may employ
accountants, legal counsel and any other experts he or she deems advisable to
assist in the administration of the Plan.

      B. Corporation Shares. The aggregate number of Corporation Shares which
may be purchased, or awarded as Service Award Contributions, under the Plan
shall not exceed 5,000,000.

      C. Adjustments. In the event the number of outstanding Corporation Shares
changes as a result of any stock split, stock dividend, recapitalization,
merger, consolidation, reorganization, combination, or exchange of shares,
split-up, split-off, spin-off, liquidation or other similar change in
capitalization, or any distribution made to holders of Corporation Shares other
than cash dividends, the number of Corporation

                                       4
<PAGE>

Shares that may be purchased, or awarded as Service Award Contributions, under
the Plan shall be automatically adjusted, and the Committee shall be authorized
to make such other equitable adjustments as it deems necessary so that the value
of the interest of the Participants shall not be decreased by reason of the
occurrence of such event. Any such adjustment shall be deemed conclusive and
binding on the Corporation, each Participant, his or her Beneficiaries and all
other interested parties.

      D. Supplements. From time to time, supplements may be attached by
amendment to and form a part of this Plan and shall be given the same effect
that such provision would have if it was incorporated within the basic text of
the Plan. Such supplements may modify or supplement the provisions of the Plan
as they apply to particular groups of Employees or groups of Participants, shall
specify the persons affected by such supplements and shall supersede the other
provisions of the Plan to the extent necessary to eliminate inconsistencies
between the Plan provisions and the provisions of such supplements.

      E. Non-Resident Aliens. With respect to non-resident alien Employees, the
Committee or Plan Administrator may adopt one or more sets of procedures and
provisions, which may be different than those included in this Plan for other
Participants, with each set of procedures and provisions applying to some or all
of such non-resident alien Employees, as determined by the Committee in its sole
discretion or the Plan Administrator in his or her sole discretion, in order to
comply with the applicable laws of the respective jurisdiction(s) in which such
non-resident alien Employees live or work and/or to take into account other
legal, tax, accounting and similar issues arising by virtue of the participation
of such non-resident alien Employees. The adoption of any such procedures and
provisions shall not be deemed an amendment to this Plan.

      F. Applicable Law. To the extent not preempted by the laws of the United
States, the laws of the State of Delaware shall be the controlling law in all
matters relating to this Plan.

SECTION IV - PARTICIPATION

      A. Eligibility. Any person who is or becomes an Employee may commence
participation in the Plan as soon as administratively feasible on or subsequent
to such individual's date of hire; provided, however, that for purposes of the
Plan, the Committee or the Plan Administrator may exclude from eligibility
non-resident aliens (or classes of non-resident aliens), if any, if the
requirements of local law, rules or regulations, including without limitation,
the tax, labor, accounting or securities laws, rules, regulations or
consequences, make participation by such non-resident aliens (or class(es) of
non-resident aliens) impractical, as determined by the Committee in its sole
discretion or the Plan Administrator in his or her sole discretion.

                                       5
<PAGE>

      B. Enrollment. Enrollment in the Plan shall be accomplished by such
procedures as are established by the Committee or the Plan Administrator from
time to time. Unless determined otherwise by the Committee or the Plan
Administrator, Payroll Withholding Contributions will commence as of the first
pay period which begins not less than ten days following a Participant's
communication of instructions to commence such contributions. Other Permitted
Contributions will be made as soon as is administratively feasible, as
determined by the Committee or the Plan Administrator, following the
Corporation's receipt of instructions to commence such contributions.

      C. Election Changes. A Participant may increase, decrease, cease or resume
the amount of his or her Payroll Withholding Contributions by communicating
further instructions pursuant to such procedures as are established by the
Committee or the Plan Administrator from time to time. Election changes shall
become effective as soon as administratively feasible after instructions have
been properly communicated. There shall be no limitation on the number of
election changes a Participant may make. A discontinuance of contributions in
and of itself shall not constitute a withdrawal from the Plan.

SECTION V - CONTRIBUTIONS

      A. Payroll Withholding Contributions. Any Payroll Withholding Contribution
shall equal at least 0.5% but not exceed 100% of a Participant's Bi-Weekly Base
Pay, net of all other applicable withholding and deductions. The Corporation
shall remit these contributions to the Custodian Bank promptly.

      B. Other Permitted Contributions. A Participant may make Other Permitted
Contributions in a single sum at such time or times permitted by the Committee
or the Plan Administrator.

      C. Matching Contributions. The Corporation shall make a Matching
Contribution equal to 15% of the Payroll Withholding Contributions, Service
Award Contributions and/or Other Permitted Contributions made by, or on behalf
of, each Participant during any calendar quarter, provided there have been no
withdrawals from the Participant's Account during such quarter. Matching
Contributions will not be made with respect to Share Retention Contributions. In
addition, Matching Contributions will not be made with respect to Payroll
Withholding Contributions, Service Award Contributions and/or Other Permitted
Contributions made during any Plan Year to the extent such contributions exceed
$25,000 in the aggregate. Matching Contributions will be made at or after the
end of each calendar quarter and shall be net of all applicable withholding and
deductions. A Participant shall be eligible to receive a Matching Contribution
with respect to a calendar quarter if there have been no withdrawals during such
quarter, even if the Participant's employment terminated during such quarter for
any reason.

                                       6
<PAGE>

      D. Share Retention Contributions. Subject to the conditions and
limitations of this Section V(D), the Corporation shall allocate Share Retention
Contributions to the Accounts of those Participants who qualify therefor.
Subject to the conditions and limitations of this Section V(D), a Participant
shall qualify for a Share Retention Contribution in a Plan Year if the
Participant is employed on the last day of the relevant Two-Plan-Year-Period,
and if, during such Two-Plan-Year-Period, there has not been a withdrawal of any
of the following:

      i. Payroll Withholding Contributions, Service Award Contributions or Other
      Permitted Contributions made during such period;

      ii. Matching Contributions made during such period;

      iii. Corporation Shares purchased with any contributions referred to in to
      Section V(D)(i) or (ii); or

      iv. Corporation Shares purchased with dividends paid with respect to any
      shares referred to in Section V(D)(iii).

      Share Retention Contributions will not be made with respect to Matching
Contributions. In addition, Share Retention Contributions will not be made with
respect to Payroll Withholding Contributions, Service Award Contributions and/or
Other Permitted Contributions made during any Plan Year to the extent such
contributions exceed $25,000 in the aggregate. Share Retention Contributions
shall be made as soon as reasonably practicable after the first day of the Plan
Year following a Two-Plan-Year-Period and shall be net of all applicable
withholding and deductions.

      Notwithstanding anything in this Section V(D) to the contrary, a
Participant whose employment terminates by reason of Retirement, death or
Disability prior to the end of a Two-Plan-Year-Period shall be eligible to
receive a Share Retention Contribution with respect to such partial
Two-Plan-Year-Period (consisting of the Plan Year during which the Participant's
employment so terminates and the immediately preceding Plan Year) if and only if
there have been no withdrawals during such period (prior to termination of
employment). The Share Retention Contribution made on behalf of any such
eligible terminated Participant with respect to such period shall be prorated
based on the number of days during the final Plan Year that the Participant was
employed.

      For purposes of this Section V(D), a Participant's employment shall be
considered to have terminated by reason of Retirement if he or she terminates
employment with eligibility for, and elects to commence receipt of, an early or
normal retirement benefit under a tax-qualified defined benefit retirement plan
maintained by the Corporation, and a Participant's employment shall be
considered to have terminated by reason of Disability if he or she terminates
employment with eligibility for,

                                       7
<PAGE>

and is awarded, disability benefits under a long-term disability plan maintained
by the Corporation.(1)

      E. Service Award Contributions. The Corporation may make Service Award
Contributions to the Accounts of those Employees whom it wishes to recognize for
service to the Corporation. Service Award Contributions are made at the
discretion of the Corporation. All Corporation Service Awards related to
Corporation Shares shall be made under this Plan through such Service Award
Contributions.

      F. Assignment of Rights Under the Plan. Unless otherwise determined by the
Committee, a Participant's Account shall not be transferable by a Participant
otherwise than by will or by the laws of intestacy; provided, however, that, a
Participant may, in accordance with Section IX(A) and in the manner established
by the Committee, designate one or more Beneficiaries to exercise the rights of
the Participant and to receive any property payable or distributable with
respect to such Participant's Account upon the death of the Participant. Except
as otherwise set forth in the Plan, during the Participant's lifetime, only the
Participant (or, if permissible under applicable law, the Participant's guardian
or legal representative) may make elections or withdrawals with respect to such
Participant's Account. Unless otherwise determined by the Committee, a
Participant's Account, or rights with respect to such Account, may not be
pledged, alienated, attached or otherwise encumbered, and any purported pledge,
alienation, attachment or encumbrance thereof shall be void and unenforceable
against the Corporation or any of its subsidiaries or affiliates.

-----------------
      (1) Please note that determination of disability and award of disability
benefits may occur retroactively long after the Participant's employment
termination date and after the date that Share Retention Contribution
determinations were otherwise made for the relevant Plan Year.

                                       8
<PAGE>

SECTION VI - ACQUISITION OF CORPORATION SHARES

      A. Application of Current Contributions. As soon as reasonably practicable
following its receipt of Payroll Withholding Contributions, Other Permitted
Contributions, Service Award Contributions, Matching Contributions and/or Share
Retention Contributions, the Custodian Bank shall purchase the maximum number of
Corporation Shares that the funds allocated to each Participant's Account may
purchase at the then-prevailing market prices. Such purchases may be in the open
market or directly from the Corporation. Corporation Shares so acquired shall be
allocated to the relevant Participant's Account.

      B. Reinvested Cash Dividends. Any cash dividends paid on Corporation
Shares allocated to any Participant's Account shall be utilized by the Custodian
Bank to purchase additional Corporation Shares at prices and in the manner
specified above.

      C. Book Entry. Unless otherwise determined by the Committee or the Plan
Administrator, Corporation Shares held under the Plan shall be held in book
entry form, and the Custodian Bank or its nominee shall be identified as the
owner thereof while such Corporation Shares remain in the Plan.

SECTION VII - RIGHTS WITH RESPECT TO SHARES HELD IN PLAN

      All rights accruing to an owner of record of Corporation Shares shall
belong to and be vested in the Participant for whose Account such Corporation
Shares are being held by the Custodian Bank, including, without limitation, the
right to receive all dividends payable in respect of such Corporation Shares,
the right to receive all notices of stockholders' meetings, the right to vote
and the right to tender or refrain from tendering such Corporation Shares in
response to a tender offer.

SECTION VIII - WITHDRAWALS FROM PLAN

      A. In-Service Withdrawals. A Participant may withdraw all or any portion
of the balance of his or her Account from the Plan during the Participant's
employment. Unless determined otherwise by the Committee or the Plan
Administrator, if the value of the Participant's Account at the time the
in-service withdrawal is requested is less than the value of ten Corporation
Shares at such time, distribution will be made to the Participant in cash.
Otherwise, the Participant may elect to receive a distribution in the form of
cash or Corporation Shares. Any brokerage commissions incurred in connection
with the sale of Corporation Shares to facilitate a distribution shall be
charged to the Participant's Account. A Participant shall not be entitled to
receive a Matching Contribution with respect to any Payroll Withholding
Contributions, Service Award Contributions and/or Other Permitted Contributions
made during a calendar quarter if the Participant has made an in-service
withdrawal during such quarter.

                                       9
<PAGE>

      B. Termination Withdrawals. A Participant or his or her Beneficiary(ies)
must submit an application to withdraw the balance of his or her account not
later than ninety days after the Participant's employment terminates due to
death, Disability, Retirement, voluntary resignation, involuntary dismissal or
any other reason, or within ninety days after the Participant or his or her
legal representative receives notice that the Plan has terminated. A withdrawal
application will be provided to the Participant or Beneficiary(ies) upon the
occurrence of any of the aforementioned circumstances. The application must be
returned to the Custodian Bank within ninety days of receipt. If the Custodian
Bank does not receive a withdrawal application by the specified deadline, it
will distribute the balance of the Participant's Account to the Participant or
his or her legal representative in the form of whole Corporation Shares
registered in the Participant's name; provided, however, that unless determined
otherwise by the Committee or the Plan Administrator, if the value of the
Participant's Account on the date of distribution is less than the value of ten
Corporation Shares at such time, the distribution will be made in cash. If the
Custodian Bank receives a withdrawal application by the specified deadline and
the value of the Participant's Account at the time the termination withdrawal is
requested is less than the value of ten Corporation Shares at such time, then
unless determined otherwise by the Committee or the Plan Administrator, the
distribution will be made in cash. Otherwise, the Participant or his or her
Beneficiary(ies) may elect to receive a distribution in the form of cash or
Corporation Shares.

      C. Fractional Shares and Brokerage Commissions. In all cases, cash will be
paid in lieu of fractional Corporation Shares. Any brokerage commissions
incurred in connection with the sale of Corporation Shares to facilitate a
distribution will be charged to the Participant's Account.

      D. Special Rule Applicable To Section 16 Insiders. Except as otherwise
determined by the Committee, a Section 16 Insider shall not be permitted to
receive a cash distribution from the Plan, if, within the previous six months,
he or she (or any other person whose transactions are attributed to the Section
16 Insider under Section 16 of the Exchange Act) either (i) acquired Corporation
Shares in the open market or pursuant to a private transaction; or (ii) made an
election under the Plan (or under any other Plan sponsored by the Corporation)
that resulted in an acquisition of equity securities of the Corporation within
the meaning of that term under Section 16 of the Exchange Act. The Committee or
Plan Administrator may make such other rules as are necessary to comply with
Section 16 of the Exchange Act, as amended from time to time.

SECTION IX - MISCELLANEOUS PROVISIONS

      A. Designation of Beneficiary. Upon becoming a Participant of the Plan,
each Participant shall submit to Comerica Incorporated, Human Resources -
Compensation, 411 West Lafayette, MC 3122, Detroit, MI 48226 (or to such other
unit

                                       10
<PAGE>

or person as designated by the Committee from time to time) a Beneficiary
Designation Form designating one or more Beneficiaries to whom the balance of
the Participant's Account is to be distributed in the event assets remain in
such Account at the time of the Participant's death, or by whom any rights of
the Participant, after the Participant's death, may be exercised. A Beneficiary
Designation Form will be effective only if it is signed by the Participant and
submitted before the Participant's death. Any subsequent Beneficiary Designation
Form properly submitted will supersede any previous Beneficiary Designation Form
so submitted. If a Participant designates a spouse as a Beneficiary, such
designation shall automatically terminate and be of no effect following the
divorce of the Participant and such individual, unless ratified in writing
post-divorce.

      If the primary Beneficiary shall predecease the Participant or the primary
Beneficiary and the Participant die in a common disaster under such
circumstances that it is impossible to determine who survived the other, the
balance of the Participant's Account shall be distributed to the alternate
Beneficiary(ies) who survive(s) the Participant in accordance with this Plan. If
there are no alternate Beneficiaries living or in existence at the date of the
Participant's death, or if the Participant has not submitted a valid Beneficiary
Designation Form to the Corporation, the balance of the Participant's Account
shall be distributed in accordance with the terms of the Plan to the legal
representative for the benefit of the Participant's estate.

      The Corporation reserves the right to distribute the balance of a
Participant's Account to his or her estate notwithstanding the designation of a
Beneficiary, if the Corporation is unable to locate the Beneficiary, a dispute
arises among Beneficiaries or under any other circumstances the Corporation
deems appropriate.

      B. Withholding of Taxes. The Corporation shall withhold from any amounts
payable to the Participant all Federal, state, city, or other taxes and/or other
amounts as legally required by reason of Participant's participation in this
Plan.

      C. Expenses. All charges of the Custodian Bank, the cost of maintenance of
the Accounts of Participants, the purchase of Corporation Shares, and the cost
of transferring Corporation Shares to the Participants and Beneficiaries shall
be borne by the Corporation; provided, however, that brokerage charges involved
in the sale of Corporation Shares, if any, shall be charged to the relevant
Participant's Account.

      D. Compliance With Legal Requirements. The Corporation shall be bound by
all applicable laws in operating this Plan and shall administer and interpret
this Plan in accordance with legal requirements.

      E. Amendment, Term and Termination. The Committee reserves the right to
amend and/or restate the Plan at any time or to terminate the Plan. The Plan
shall continue indefinitely until terminated by the Committee.

                                       11
<PAGE>

SECTION X - EFFECTIVE DATE OF PLAN

      This Plan will be effective as of June 30, 2003, subject to approval by at
least a majority of the outstanding shares of common stock of the Corporation
present and having voting power at the meeting at which this Plan is put to a
vote.

                                       12
<PAGE>

                                               COMERICA INCORPORATED

                                               By: /s/ James E. Lake
                                                  ------------------
                                               James E. Lake
                                               Its: Senior Vice President and
                                               Director of Human Resources

Comerica Bank, as Custodian Bank, hereby signifies the acceptance of its
responsibilities contained herein.

                                               COMERICA BANK AS CUSTODIAN BANK

                                               By: /s/ Cheryl A. Derezinski
                                                  -------------------------
                                               Cheryl A. Derezinski
                                               Its: Senior Vice President

                                       13