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                                                                 EXHIBIT 10-34-2

                             FIRST AMENDMENT TO THE
                               EXELON CORPORATION
                          EMPLOYEE STOCK PURCHASE PLAN

      The Exelon Corporation Employee Stock Purchase Plan (the "Plan"),
originally established as of June 1, 2001, is hereby amended in the following
respect:

                                        I

      Section 12 of the Plan is amended by deleting the number "5,000,000" from
the first sentence thereof and inserting in its place the number "3,000,000".

                                       II

      Except as herein amended, the Plan shall remain in full force and effect.

      IN WITNESS WHEREOF, Exelon Corporation has caused this instrument to be
executed by its duly authorized officer effective as of March 8, 2002.

                                              EXELON CORPORATION

                                              By:_____________________________
                                                       J. Barry Mitchell
                                                       Treasurer<PAGE>

                                                                   EXHIBIT 10-35

                               PECO Energy Company
                        Supplemental Pension Benefit Plan
                    (As Amended and Restated January 1, 2001)

      PECO Energy Company ("PECO" or the "Company") originally established the
PECO Energy Company Deferred Compensation and Supplemental Pension Benefit Plan
(the "Executive Plan") and the PECO Energy Company Management Group Deferred
Compensation and Supplemental Pension Benefits Plan (the "Management Plan"). The
outstanding shares of PECO have been exchanged with shares of Exelon Corporation
("Exelon"), causing Exelon to become PECO's parent (the "Share Exchange").
Immediately thereafter, Unicom Corporation merged with and into Exelon (the
"Merger"). In connection with the Share Exchange and Merger, Exelon assumed
sponsorship of both the Executive Plan and the Management Plan. Effective
January 1, 2001, the deferred compensation obligations of both the Executive
Plan and the Management Plan were assumed by the [EXELON CORPORATION DEFERRED
COMPENSATION PLAN], and the supplemental pension benefit obligations of the
Executive Plan and the Management Plan were merged to form this plan (the
"Plan").

      The purposes of this Plan are to permit the total pension of certain
management and executive participants in the PECO Energy Company Service Annuity
Plan (the "Service Annuity Plan") to be determined on a basis that is no less
favorable than for all other participants in the Service Annuity Plan, to offset
the impact of deferrals under certain incentive compensation programs on the
pensions of participating employees, and to provide uniform rules and
regulations of plan administration.

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            1. Administration. This Plan shall be administered by the
Compensation Committee (the "Committee") of the Board of Directors of Exelon
(the "Board"). The Committee shall interpret the Plan; make factual
determinations; establish such rules and regulations of plan administration that
it deems appropriate; and appoint an administrator to assist the Committee in
its responsibilities. The Committee's decisions with respect to the
construction, administration and interpretation of the Plan shall be conclusive
and binding, unless otherwise determined by the Board. The cost of the plan
administration shall be paid by Exelon.

            2. Eligibility. Eligibility under the Plan is restricted to key
management and executive employees of Exelon or any of its Subsidiaries (as
defined below) who are selected by the Committee and participate in the Service
Annuity Plan. For purposes of this Plan, "Subsidiary" shall mean a corporation
in which Exelon owns, directly or indirectly, at least 50% of the combined
voting power of all classes of stock entitled to vote.

            3. Supplemental Pension Benefit.

                  (a) (1) Exelon will supplement a participant's monthly pension
or preretirement death benefit payable under the Service Annuity Plan by the
amount which is the difference, if any, between such pension or preretirement
death benefit and the monthly pension or preretirement death benefit which would
have been payable under the Service Annuity Plan as if: (i) the provisions of
the Service Annuity Plan were administered without regard to the maximum benefit
limitations or the maximum compensation limitations imposed under the Internal
Revenue Code of 1986, as amended; (ii) for purposes of calculating the
participant's benefit under Section 3.1(a) (the "2% accrued" formula), the
participant's salary includes in the year payable (whether or not deferred) the
amount of any award under any annual incentive compensation program maintained
by Exelon or the Subsidiary employing the participant; (iii) for purposes of
calculating the participant's benefit under Section 3.1(b) (the "minimum"
formula), the participant's annual base salary includes the amount of any award
under any annual incentive

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compensation program maintained by Exelon or the Subsidiary employing the
participant, whether paid currently or deferred, and in either case imputed
ratably over the months worked by the participant in the year earned; and (iv)
for purposes of both benefit formulas under the Service Annuity Plan, the
participant's salary had not been reduced (whether before or after the Effective
Date) in connection with a deferral of cash compensation. In addition, for any
participant whose compensation is established by the Board, such supplemental
benefit will also reflect the following adjustment: for purposes of calculating
the participant's benefit under Section 3.1(b) (the "minimum" formula), the
participant's annual base salary shall include the amount of any award under
PECO's prior Incentive Compensation Plan, whether paid currently or deferred,
and in either case imputed ratably over the months worked by the participant in
the year earned. Except as otherwise determined by the Committee, or as
otherwise elected by the participant under this Paragraph, supplemental pension
and death benefits will be in the same form and paid to the employee (or on his
or her behalf, to his or her beneficiaries) in the same manner as payment of
retirement and death benefits under the Service Annuity Plan. This supplement
shall also reflect to the appropriate extent any post-retirement benefit
increases with respect to benefits under the Service Annuity Plan. The
supplemental benefit payable under this Plan for any participant identified in
an Appendix to this Plan shall be made in the manner set forth herein with such
adjustments as are described in such Appendix.

            (2) (A) In addition to the supplement described in Paragraph
3(a)(1), Exelon will supplement the monthly pension or preretirement death
benefit payable

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under the Service Annuity Plan to an `eligible participant' (as defined below)
by the amount which is the difference between (i) the sum of such pension or
preretirement death benefit, if any, and the supplement payable under Paragraph
3(a)(1), if any, and (ii) the monthly pension or preretirement death benefit
which would be payable under the Service Annuity Plan if: (x) for purposes of
Sections 3.1(a) and 3.1(b), such participant's aggregate compensation and annual
base salary included the amount described in Section 5.1(b) of the participant's
change in control agreement and was determined without regard to the maximum
benefit limitations or the maximum compensation limitations imposed under
sections 415 and 401(a)(17), respectively, of the Internal Revenue Code of 1986,
as amended; provided, however, that such amount will be taken into account as if
it was earned by the participant uniformly over the `severance period' (as
defined below), and (y) for purposes of Section 3.1(b) and Articles IV and V,
such participant is deemed to have attained the age he will attain as of the
last day of the severance period and completed the number of years (for both
vesting and benefit accrual purposes) he would otherwise have completed as of
the last day of the severance period.

                  (B) Except as otherwise determined by the Committee, or as
otherwise elected by the participant under this Paragraph, supplemental pension
and death benefits will be in the same form and paid to the participant (or on
his or her behalf, to his or her beneficiaries) in the same manner as payment of
retirement and death benefits under the Service Annuity Plan. Notwithstanding
the preceding sentence, an eligible participant may receive the supplement
described in Paragraph 3(a)(2) immediately upon his termination of employment in
the form of a lump sum or in any other payment form available under the Service
Annuity Plan. This supplement will also reflect to the appropriate extent any
post-retirement benefit increases with respect to benefits under the Service
Annuity Plan.

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                  (C) For purposes of this Paragraph 3(a)(2), the following
definitions will apply:

            'Eligible participant' means a participant who has entered into a
            change in control agreement with PECO in contemplation of the merger
            between PECO and Unicom Corporation (i) whose employment is
            terminated by PECO during the Employment Period for a reason other
            than Cause or Disability, or (ii) who terminates his employment
            during the Employment Period for Good Reason (as those terms are
            defined in the applicable change in control agreement).

            'Severance Period' equals (i) in the case of a senior officer of
            PECO, 36 months, (ii) in the case of a vice president other than a
            senior officer of PECO, 24 months, and (iii) in the case of an
            eligible participant in compensation band D or above, other than a
            senior officer or vice president of PECO, 18 months.

            (b) (1) In any calendar year before the year of retirement but in no
event less than ninety days prior to retirement, a participant, while employed
by Exelon or any of its Subsidiaries, may elect to receive the present value of
all or a portion (in increments of 25%) of the supplemental retirement benefit
payable to the participant under Paragraph 3(a) in a lump sum at retirement;
provided, however, that no such election shall accelerate the commencement of
benefits. Notwithstanding the foregoing, however, a participant who retires from
employment with Exelon or any of its Subsidiaries under any early retirement
incentive arrangement or non-recurring reduction

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in force (including, but not limited to, the 1990 Special Retirement and Service
Completion Plan, the 1993 Nuclear Voluntary Retirement Incentive Plan, the 1993
Nuclear Voluntary Separation Plan, the 1993 Nuclear Involuntary Separation Plan,
the 1994 Voluntary Retirement Incentive Plan, the 1994 Voluntary Separation
Incentive Plan, and the 1998 Workforce Reduction Program) may, prior to
separation from service with Exelon or any of its Subsidiaries, make a one-time
irrevocable election to receive a lump sum distribution of the present value of
all or a portion of the supplemental retirement benefit payable to the
participant under Paragraph 3(a) in accordance with the terms of such
arrangement or reduction in force and, if such election is approved by Exelon,
receive such a distribution upon his or her retirement.

            (2) The present value of amounts payable in a lump sum pursuant to
this Paragraph 3(b) will be actuarially determined by discounting the expected
stream of annuity payments (based upon the life expectancy of the participant
and, if applicable, the life expectancy of the participant's beneficiary as
provided under the Contingent Annuity Option of the Service Annuity Plan,
determined as of the date of payment under the mortality table used in the most
recent actuarial analysis of the Service Annuity Plan) at a rate equivalent to
the Pension Benefit Guaranty Corporation (PBGC) Immediate Annuity Rate in effect
on January 1 of the year of retirement; provided, however, that a lump sum
payable pursuant to a lump sum election made prior to June 1, 1993 (even if such
election was later modified to apply to a lesser portion of the amount payable)
shall be valued using the PBGC Immediate Annuity Rate in effect during the month
in which the election is made, if the use of such rate would result in a larger
lump sum payment. Such calculation shall reflect the Contingent Annuity Option
benefit under

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the Service Annuity Plan if the participant otherwise satisfies the conditions
for that benefit, but shall not reflect any possible post-retirement benefit
increases; provided, however, that, if the participant's Contingent Annuity
Option election under the Service Annuity Plan is not irrevocable at the time
the lump sum payment is made hereunder, the participant will receive an initial
lump sum payment reflecting the Contingent Annuity Option resulting in the
smallest lump sum payment from the Plan and, at age 65 (or at the participant's
death, if earlier), a payment will be made to the participant (or his or her
beneficiary) equal to the balance due the participant (which shall be the
present value of the difference between the value of the total pension payable
to the participant or beneficiary at such time over the sum of the value of
benefits payable to the participant or beneficiary under the Service Annuity
Plan and the lump sum previously paid, taking into account the Contingent
Annuity Option then in effect, the Contingent Annuity Option in effect between
retirement and age 65, and increases in benefit payable under the Service
Annuity Plan due to adjustment of Internal Revenue Code limitations, and
reflecting the interest rate used to calculate the prior lump sum). The specific
calculation methodology and manner of payment, which will be made in a manner
acceptable to the Committee, will be applied in a uniform, non-discriminatory
fashion.

            (c) (1) A participant may elect to have supplemental death benefits
under Paragraph 3(a) paid to such beneficiary or beneficiaries as the
participant may designate in writing, in the manner specified by the Committee.
A change in beneficiary designation may be made at any time until the
participant's death, notwithstanding that the form and amount of the benefit may
be fixed upon the participant's termination of employment with Exelon or any of
its Subsidiaries or other inter vivos determining event.

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In the absence of a written beneficiary designation, death benefits will be paid
to the beneficiary or beneficiaries entitled to the participant's survivor and
death benefits under the Service Annuity Plan.

            (2) Should a participant who has made a lump sum election as
described in Paragraph 3(b)(1) prior to June 1, 1993 die between the time such
election is made and the date payments are scheduled to begin, the present value
of supplemental death benefits payable to the participant's beneficiary under
Paragraph 3(a) shall be paid in a lump sum to the participant's beneficiary as
soon as administratively practicable following the participant's death;
provided, however, that the participant has not made a contrary election
pursuant to the following sentence. In accordance with procedures prescribed by
the Committee, a participant (including a participant described in the preceding
sentence), while employed by Exelon or any of its Subsidiaries, may elect, or
revoke or change a prior election, to have the present value of all or a portion
of the supplemental death benefits payable to the participant's beneficiary
under Paragraph 3(a) paid to the beneficiary in a lump sum as soon as
administratively practicable following the participant's death; provided,
however, that such election, or revocation or change, will not be effective
unless made in any calendar year prior to the year in which the participant dies
and at least ninety (90) days prior to the date of such participant's death.

            (3) The present value of amounts payable in a lump sum pursuant to
Paragraph 3(c)(2) will be actuarially determined by discounting the expected
stream of annuity payments (based upon the beneficiary's life expectancy
determined as of the date of payment under the mortality table used in the most
recent actuarial analysis of the Service Annuity Plan) at a rate equivalent to
the Pension Benefit Guaranty Corporation

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      (PBGC) Immediate Annuity Rate in effect on January 1 of the year of the
      participant's death; provided, however, that a lump sum payable to the
      beneficiary of a participant who made a lump sum election under this
      Paragraph 3 prior to June 1, 1993 (even if such election was later
      modified, or revoked and reinstated, with respect to the participant's
      beneficiary) shall be valued using the PBGC Immediate Annuity Rate in
      effect during the month such election was made, if the use of such rate
      would result in a larger lump sum payment.

            4. Amendment or Discontinuance. The Plan may be altered, amended,
suspended, or terminated at any time by the Compensation Committee of Exelon.

            5. No Right to Continued Employment. The Plan shall not confer upon
any person any right to be continued in the employment of Exelon or any of its
Subsidiaries.

            6. Governing Law. The Plan shall be governed by the law of the
Commonwealth of Pennsylvania.

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                                   APPENDIX A

            Exelon shall supplement the monthly pension or preretirement death
benefit payable under the Service Annuity Plan to Edward G. Bauer ("Bauer") and
William F. Thompson ("Thompson") or their beneficiaries as follows: The amount
of the supplement payable to each shall be the difference, if any, between such
pension or preretirement death benefit and the monthly pension or preretirement
death benefit which would have been payable to him under the Service Annuity
Plan if, in the case of Bauer seven additional years, and in the case of
Thompson, six additional years, of past service credits had been credited
thereunder and were used to calculate his benefits. This supplement shall be
paid under the Plan, and shall also reflect to the appropriate extent any
post-retirement benefit increases granted with respect to benefits under the
Service Annuity Plan. Supplemental pension and death benefits will be paid in
the same form to Bauer and Thompson (or on their behalf, to their beneficiaries)
in the same manner as payment of retirement and death benefits under the Service
Annuity Plan, except the Committee may, in its sole discretion, accelerate the
payment of benefits to a beneficiary. In all other respects, the terms of the
Plan shall govern Bauer's and Thompson's benefits provided hereunder.

                                      A-1
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                                   APPENDIX B

            Exelon shall supplement the monthly pension or preretirement death
benefit payable under the Service Annuity Plan to Corbin A. McNeill, Jr. in the
following manner:

            1. If Mr. McNeill's employment with Exelon or any of its
Subsidiaries terminates after he has nonforfeitable rights to a pension payable
under the Service Annuity Plan, Exelon will supplement Mr. McNeill's pension or,
in the case of a pre-retirement death benefit, Mr. McNeill's beneficiary's
pension, by the additional amount which would be payable under the Service
Annuity Plan if Mr. McNeill's service for purposes of calculating benefits is
increased by twenty additional years.

            2. Payments authorized under this Resolution shall be in the form
and manner provided under Paragraph 3 of the Plan, including any post-retirement
benefit increases and settlement options otherwise applicable to payments
thereunder.

            3. In all other respects, the Plan shall govern Mr. McNeill's
benefit provided hereunder.

                                      C-1
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                                   APPENDIX C

            Exelon shall supplement the monthly pension or preretirement death
benefit payable under the Service Annuity Plan to Joseph A. Carter and James W.
Durham in the following manner:

            1. If the employment of Mr. Carter or Mr. Durham with Exelon or any
of its subsidiaries terminates after he has nonforfeitable rights to a pension
payable under the Service Annuity Plan, Exelon will supplement the individual's
pension or, in the case of the pre-retirement death benefit, the individual's
beneficiary pension, by the additional amount which would be payable under the
Service Annuity Plan if the individual's service for purposes of calculating
benefits were supplemented by an additional year of service for each completed
year of service, to a maximum of 10 additional years of service.

            2. Payments authorized under this Appendix shall be in the form and
manner provided under Paragraph 3 of the Plan, including any post-retirement
benefit increases and settlement options otherwise applicable to payments
thereunder.

            3. In all other respects, the Plan shall govern Mr. Carter's and Mr.
Durham's benefits provided hereunder.

                                      D-1
<PAGE>

                                   APPENDIX D

            Exelon shall supplement the monthly pension or preretirement death
benefit payable under the Service Annuity Plan to William J. Kaschub and
Gwendolyn S. King in the following manner:

            1. If the employment of Mr. Kaschub or Ms. King with Exelon or any
of its Subsidiaries terminates after the individual has nonforfeitable rights to
a pension payable under the Service Annuity Plan, Exelon will supplement the
individual's pension or, in the case of the pre-retirement death benefit, the
pension of the individual's beneficiary, by the additional amount which would be
payable under the Service Annuity Plan if the individual's service for purposes
of calculating benefits were supplemented by an additional year of service for
each completed year of service, to a maximum of 10 additional years of service.

            2. Payments authorized under this resolution shall be in the form
and manner provided under Paragraph 3 of the Plan, including any post-retirement
benefit increases and settlement options otherwise applicable to payments
thereunder.

            3. In all other respects, the Plan shall remain in full force and
effect as to Mr. Kaschub and Ms. King's benefits provided hereunder.

                                      B-1
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                                   APPENDIX E

            Exelon shall supplement the monthly pension or preretirement death
benefit payable under the Service Annuity Plan to William L. Bardeen in the
following manner:

            1. If Mr. Bardeen's employment with Exelon or any of its
subsidiaries terminates after he has nonforfeitable rights to a pension payable
under the Service Annuity Plan, Exelon will supplement Mr. Bardeen's pension or,
in the case of a pre-retirement death benefit, the pension of Mr. Bardeen's
beneficiary, by the additional amount which would be payable under the Service
Annuity Plan if Mr. Bardeen's service for purposes of calculating benefits is
increased by twenty additional years.

            2. Payments authorized under this Resolution shall be in the form
and manner provided under Paragraph 3 of the Plan, including any post-retirement
benefit increases and settlement options otherwise applicable to payments
thereunder.

            3. In all other respects, the Plan shall govern Mr. Bardeen's
benefits provided hereunder.

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                                   APPENDIX F

            Exelon shall supplement the monthly pension or preretirement death
benefit payable under the Service Annuity Plan to Gregory A. Cucchi in the
following manner:

            1. If Mr. Cucchi's employment with Exelon or any of its subsidiaries
terminates after he has nonforfeitable rights to a pension payable under the
Service Annuity Plan, Exelon will supplement Mr. Cucchi's pension or, in the
case of a pre-retirement death benefit, the pension of Mr. Cucchi's beneficiary,
by the additional amount which would be payable under the Service Annuity Plan
if Mr. Cucchi's service for purposes of calculating benefits included Mr.
Cucchi's service as Chief Executive Officer of Exelon Infrastructure Services,
Inc.

            2. Payments authorized under this Resolution shall be in the form
and manner provided under Paragraph 3 of the Plan, including any post-retirement
benefit increases and settlement options otherwise applicable to payments
thereunder.

            3. In all other respects, the Plan shall govern Mr. Cucchi's
benefits provided hereunder.

                                      F-2
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                                   APPENDIX G

            Exelon shall supplement the monthly pension or preretirement death
benefit payable under the Service Annuity Plan to James W. Langenbach in the
following manner:

            1. If Mr. Langenbach's employment with Exelon or any of its
subsidiaries terminates before he becomes eligible for a vested pension from the
Service Annuity Plan, Exelon will supplement Mr. Langenbach's pension or, in the
case of a pre-retirement death benefit, the pension of Mr. Langenbach's
beneficiary, by the additional amount which would be payable under the Service
Annuity Plan if Mr. Langenbach had been credited with eligibility and vesting
service (but not benefit accrual service) under the Service Annuity Plan for
such service credited to him under the GPU Companies Employee Pension Plan
immediately prior to the date he began employment with PECO.

            2. Payments authorized under this Resolution shall be in the form
and manner provided under Paragraph 3 of the Plan, including any post-retirement
benefit increases and settlement options otherwise applicable to payments
thereunder.

            3. In all other respects, the Plan shall govern Mr. Langenbach
benefits provided hereunder.

                                      F-3

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