QuickLinks -- Click here to rapidly navigate through this document

Exhibit 10(k)

This document constitutes part of a prospectus covering securities that have
been registered under the Securities Act of 1933.

Constellation Energy Group, Inc.
Management Long-Term Incentive Plan
(Plan)

        1.    Objective.    The objective of this Plan is to increase
shareholder value by providing a long-term incentive to reward management level
and other designated employees of Constellation Energy and its Subsidiaries,
whose responsibilities include the continued growth, development, and financial
success of Constellation Energy and its Subsidiaries, for the continued
profitable performance of Constellation Energy and its Subsidiaries. The Plan is
also designed to assist Constellation Energy and its Subsidiaries to retain
talented and motivated management level and other designated employees and to
increase their ownership of Constellation Energy common stock.

        2.    Definitions.    All singular terms defined in this Plan will
include the plural and vice versa. As used herein, the following terms will have
the meaning specified below:

        "Award" means individually or collectively, Restricted Stock, Options,
Performance Units, Stock Appreciation Rights, or Dividend Equivalents granted
under this Plan.

        "Board" means the Board of Directors of Constellation Energy.

        "Book Value" means the book value of a share of Stock determined in
accordance with Constellation Energy's regular accounting practices as of the
last business day of the month immediately preceding the month in which a Stock
Appreciation Right is exercised as provided in Section 10.

        "Constellation Energy" means Constellation Energy Group, Inc., a
Maryland corporation, or its successor, including any "New Company" as provided
in Section 14I.

        "Code" means the Internal Revenue Code of 1986, as amended. Reference in
the Plan to any section of the Code will be deemed to include any amendments or
successor provisions to such section and any regulations promulgated thereunder.

        "Date of Grant" means the date on which the granting of an Award is
authorized by the Plan Administrator or such later date as may be specified by
the Plan Administrator in such authorization.

        "Date of Retirement" means the date of Retirement or Early Retirement.

        "Disability" means the determination that a Participant is "disabled"
under the Constellation Energy disability plan in effect at that time.

        "Dividend Equivalent" means an award granted under Section 11.

        "Early Retirement" means retirement prior to the Normal Retirement Date.

        "Earned Performance Award" means an actual award of a specified number
of Performance Units (or shares of Restricted Stock, as the context requires)
which the Plan Administrator has determined have been earned and are payable
(or, in the case of Restricted Stock, earned and with respect to which
restrictions will lapse) for a particular Performance Period.

        "Eligible Employee" means any person employed by Constellation Energy or
a Subsidiary on a regularly scheduled basis who satisfies all of the
requirements of Section 5.

        "Exercise Period" means the period or periods during which a Stock
Appreciation Right is exercisable as described in Section 10.

        "Fair Market Value" means the average of the highest and lowest price at
which the Stock was sold regular way on the New York Stock Exchange-Composite
Transactions on a specified date.

--------------------------------------------------------------------------------

        "Incentive Stock Option" means an incentive stock option within the
meaning of Section 422 of the Code.

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

        "Normal Retirement Date" is the retirement date as described in the
Pension Plan or a Subsidiary's retirement or pension plan.

        "Option" or "Stock Option" means either a nonqualified stock option or
an incentive stock option granted under Section 8.

        "Option Period" or "Option Periods" means the period or periods during
which an Option is exercisable as described in Section 8.

        "Participant" means an employee of Constellation Energy or a Subsidiary
who has been granted an Award under this Plan.

        "Pension Plan" means the Pension Plan of Constellation Energy
Group, Inc. as may be amended from time to time.

        "Performance-Based" means that in determining the amount of a Restricted
Stock Award payout, the Plan Administrator will take into account the
performance of the Participant, Constellation Energy, one or more Subsidiaries,
or any combination thereof.

        "Performance Period" means a period of time, established by the Plan
Administrator at the time an Award is granted, during which corporate and/or
individual performance is measured.

        "Performance Unit" means a unit of measurement equivalent to such amount
or measure as defined by the Plan Administrator which may include, but is not
limited to, dollars, market value shares, or book value shares.

        "Plan Administrator" means, as set forth in Section 4, the Chief
Executive Officer of Constellation Energy.

        "Restricted Stock" means an Award granted under Section 7.

        "Retirement" means retirement on or after the "Normal Retirement Date"
(as such term is defined in the Pension Plan or a Subsidiary's retirement or
pension plan).

        "Service-Based" means that in determining the amount of a Restricted
Stock Award payout, the Plan Administrator will take into account only the
period of time that the Participant performed services for Constellation Energy
or its Subsidiaries since the Date of Grant.

        "Stock" means the common stock, without par value, of Constellation
Energy.

        "Stock Appreciation Right" means an Award granted under Section 10.

        "Subsidiary(ies)" means any corporation of which 20% or more of its
outstanding voting stock or voting power is beneficially owned, directly or
indirectly, by Constellation Energy.

        "Target Performance Award" means a targeted award of a specified number
of Performance Units (or shares of Restricted Stock, as the context requires)
which may be earned and payable (or, in the case of Restricted Stock, earned and
with respect to which restrictions will lapse) based upon the performance
objectives for a particular Performance Period, all as determined by the Plan
Administrator. The Target Performance Award will be a factor in the Plan
Administrator's ultimate determination of the Earned Performance Award.

        "Termination" means resignation or discharge from employment with
Constellation Energy or any of its Subsidiaries except in the event of death,
Disability, Retirement or Early Retirement.

2

--------------------------------------------------------------------------------

        3.    Effective Date and Duration.

        A.    Effective Date.    The Plan became effective as of February 1,
1998.

        B.    Period for Grants of Awards.    Awards may be made as provided
herein for a period of 10 years after February 1, 1998.

        C.    Grants Outstanding.    Grants outstanding at the effective time of
the share exchange between Constellation Energy and the common stockholders of
Baltimore Gas and Electric Company (BGE) were converted from BGE common
stock-based grants to Constellation Energy common stock-based grants.

        4.    Plan Administration.    The Chief Executive Officer of
Constellation Energy is the Plan Administrator and has sole authority (except as
specified otherwise herein) to determine all questions of interpretation and
application of the Plan, or of the terms and conditions pursuant to which Awards
are granted, exercised or forfeited under the Plan provisions, and, in general,
to make all determinations advisable for the administration of the Plan to
achieve its stated objective. Such determinations shall be final and not subject
to further appeal. The Plan Administrator shall have the power to delegate all
or any part of his/her duties to one or more designees, and to withdraw such
authority, by written designation.

        5.    Eligibility.    Each employee of Constellation Energy who holds a
management level position, and other employees of Constellation Energy and its
Subsidiaries, may be designated by the Plan Administrator as a Participant, from
time to time, with respect to one or more Awards. No employee of Constellation
Energy or its Subsidiaries shall have any right to be granted an Award under
this Plan.

        6.    Grant of Awards and Limitation of Number of Shares Awarded.    The
Plan Administrator may, from time to time, grant Awards to one or more Eligible
Employees, provided that (i) subject to any adjustment pursuant to Section 14H,
the aggregate number of shares of Stock subject to Awards under this Plan may
not exceed three million (3,000,000) shares; (ii) to the extent that an Award
lapses or the rights of the Participant to whom it was granted terminate, any
shares of Stock subject to such Award shall again be available for the grant of
an Award under the Plan; and (iii) shares delivered by Constellation Energy
under the Plan may be authorized and unissued Stock, Stock held in the treasury
of Constellation Energy, or Stock purchased on the open market (including
private purchases) in accordance with applicable securities laws.

        7.    Restricted Stock Awards.

        A.    Grants of Restricted Shares.    One or more shares of Restricted
Stock may be granted to any Eligible Employee. The Restricted Stock will be
issued to the Participant on the Date of Grant without the payment of
consideration by the Participant. The Restricted Stock will be issued either in
the name of the Participant or in an agent account on behalf of one or more
Participants, and will bear a restrictive legend prohibiting sale, transfer,
pledge or hypothecation of the Restricted Stock until the expiration of the
restriction period.

        The Plan Administrator may also impose such other restrictions and
conditions on the Restricted Stock as it deems appropriate, and will designate
the grant as either a Service-Based or Performance-Based Award.

        Upon issuance to the Participant of the Restricted Stock, the
Participant will have the right to vote the Restricted Stock, and subject to the
Plan Administrator's discretion, to receive the cash dividends distributable
with respect to such shares, with such dividends treated as compensation to the
Participant. The Plan Administrator, in his/her sole discretion, may direct the
accumulation and payment of distributable dividends to the Participant at such
times, and in such form and manner, as determined by the Plan Administrator.

3

--------------------------------------------------------------------------------

        B.    Service-Based Award.

        i.    Restriction Period.    At the time a Service-Based Restricted
Stock Award is granted, the Plan Administrator will establish a restriction
period applicable to such Award which will be not less than one year and not
more than ten years. Each Restricted Stock Award may have a different
restriction period, at the discretion of the Plan Administrator.

        ii.    Forfeiture or Payout of Award.    In the event a Participant
ceases employment during a restriction period, a Restricted Stock Award is
subject to forfeiture or payout (i.e., removal of restrictions) as follows:
(a) Termination—the Restricted Stock Award is completely forfeited;
(b) Retirement, Disability or death—payout of the Restricted Stock Award is
prorated for service during the period; or (c) Early Retirement—if at the
Participant's request, the payout or forfeiture of the Restricted Stock Award is
determined at the discretion of the Plan Administrator, or if at Constellation
Energy's request, payout of the Restricted Stock Award is prorated for service
during the period; provided, however, that the Plan Administrator may modify the
above if it determines at his/her sole discretion that special circumstances
warrant such modification.

        Any shares of Restricted Stock which are forfeited will be transferred
to Constellation Energy.

        Upon completion of the restriction period, all Award restrictions will
expire and certificates representing the Award will be issued (the payout)
without the restrictive legend described in Section 7A.

        C.    Performance-Based Award.

        i.    Restriction Period.    At the time a Performance-Based Restricted
Stock Award is granted, the Plan Administrator will establish a restriction
period applicable to such Award which will be not less than one year and not
more than ten years. Each Restricted Stock Award may have a different
restriction period, at the discretion of the Plan Administrator. The Plan
Administrator will also establish a Performance Period.

        ii.    Performance Objectives.    The Plan Administrator will determine,
no later than 90 days after the beginning of each Performance Period, the
performance objectives for each Participant's Target Performance Award and the
number of shares of Restricted Stock for each Target Performance Award that will
be issued on the Date of Grant. Performance objectives may vary from Participant
to Participant and will be based upon such performance criteria or combination
of factors as the Plan Administrator deems appropriate, which may include, but
not be limited to, the performance of the Participant, Constellation Energy, one
or more Subsidiaries, or any combination thereof. Performance Periods may
overlap and Participants may participate simultaneously with respect to
Performance-Based Restricted Stock Awards for which different Performance
Periods are prescribed.

        If, during the course of a Performance Period significant events occur
as determined in the sole discretion of the Plan Administrator, which the Plan
Administrator expects to have a substantial effect on a performance objective
during such period, the Plan Administrator may revise such objective.

        iii.    Forfeiture or Payout of Award.    As soon as practicable after
the end of each Performance Period, the Plan Administrator will determine
whether the performance objectives and other material terms of the Award were
satisfied. The Plan Administrator's determination of all such matters will be
final and conclusive.

        As soon as practicable after the later of (i) the date the Plan
Administrator makes the above determination, or (ii) the completion of the
restriction period, the Plan Administrator will determine the Earned Performance
Award for each Participant. Such determination may result in forfeiture of all
or some shares of Restricted Stock (if Target Performance Award performance
objectives were not

4

--------------------------------------------------------------------------------

attained), or the issuance of additional shares of Stock (if Target Performance
Award performance objectives were exceeded), and will be based upon such factors
as the Plan Administrator determines at his/her sole discretion, but including
the Target Performance Award performance objectives.

        In the event a Participant ceases employment during a restriction
period, the Restricted Stock Award is subject to forfeiture or payout (i.e.,
removal of restrictions) as follows: (a) Termination—the Restricted Stock Award
is completely forfeited; (b) Retirement, Disability or death—payout of the
Restricted Stock Award is prorated taking into account factors including, but
not limited to, service during the period; and the performance of the
Participant during the portion of the Performance Period before employment
ceased; or (c) Early Retirement—if at the Participant's request, the payout or
forfeiture of the Restricted Stock Award is determined at the discretion of the
Plan Administrator, or if at Constellation Energy's request, payout of the
Restricted Stock Award is prorated taking into account factors including, but
not limited to, service during the period and the performance of the Participant
during the portion of the Performance Period before employment ceased; provided,
however, that the Plan Administrator may modify the above if it determines at
his/her sole discretion that special circumstances warrant such modification.

        Any shares of Restricted Stock which are forfeited will be transferred
to Constellation Energy.

        With respect to shares of Restricted Stock for which restrictions lapse,
certificates will be issued (the payout) without the restrictive legend
described in Section 7A. Certificates will also be issued for additional Stock,
if any, awarded to the Participant because Target Performance Award performance
objectives were exceeded.

        D.    Waiver of Section 83(b) Election.    Unless otherwise directed by
the Plan Administrator, as a condition of receiving an Award of Restricted
Stock, a Participant must waive in writing the right to make an election under
Section 83(b) of the Code to report the value of the Restricted Stock as income
on the Date of Grant.

        8.    Stock Options

        A.    Grants of Options.    One or more Options may be granted to any
Eligible Employee on the Date of Grant without the payment of consideration by
the Participant.

        B.    Stock Option Agreement.    Each Option granted under the Plan will
be evidenced by a "Stock Option Agreement" between Constellation Energy and the
Participant containing provisions determined by the Plan Administrator,
including, without limitation, provisions to qualify Incentive Stock Options as
such under Section 422 of the Code if directed by the Plan Administrator at the
Date of Grant; provided, however, that each Incentive Stock Option Agreement
must include the following terms and conditions: (i) that the Options are
exercisable, either in total or in part, with a partial exercise not affecting
the exercisability of the balance of the Option; (ii) every share of Stock
purchased through the exercise of an Option will be paid for in full at the time
of the exercise; (iii) each Option will cease to be exercisable, as to any share
of Stock, at the earliest of (a) the Participant's purchase of the Stock to
which the Option relates, (b) the Participant's exercise of a related Stock
Appreciation Right, or (c) the lapse of the Option; (iv) Options will not be
transferable by the Participant except by Will or the laws of descent and
distribution and will be exercisable during the Participant's lifetime only by
the Participant or by the Participant's guardian or legal representative; and
(v) notwithstanding any other provision, in the event of a public tender for all
or any portion of the Stock or in the event that any proposal to merge or
consolidate Constellation Energy with another company is submitted to the
stockholders of Constellation Energy for a vote, the Plan Administrator, in
his\her sole discretion, may declare any previously granted Option to be
immediately exercisable.

        C.    Option Price.    The Option price per share of Stock will be set
by the grant, but will be not less than 100% of the Fair Market Value at the
Date of Grant.

5

--------------------------------------------------------------------------------

        D.    Form of Payment.    At the time of the exercise of the Option, the
Option price will be payable in cash or in other shares of Stock or in a
combination of cash and other shares of Stock, in a form and manner as required
by the Plan Administrator in his/her sole discretion. When Stock is used in full
or partial payment of the Option price, it will be valued at the Fair Market
Value on the date the Option is exercised.

        E.    Other Terms and Conditions.    The Option will become exercisable
in such manner and within such Option Period or Periods, not to exceed 10 years
from its Date of Grant, as set forth in the Stock Option Agreement upon payment
in full. Except as otherwise provided in this Plan or in the Stock Option
Agreement, any Option may be exercised in whole or in part at any time.

        F.    Lapse of Option.    An Option will lapse upon the earlier of:
(i) 10 years from the Date of Grant, or (ii) at the expiration of the Option
Period set by the grant. If the Participant ceases employment within the Option
Period and prior to the lapse of the Option, the Option will lapse as follows:
(a) Termination—the Option will lapse on the effective date of the Termination;
or (b) Retirement, Early Retirement, or Disability—the Option will lapse at the
expiration of the Option Period set by the grant; provided, however, that the
Plan Administrator may modify the above if he/she determines in his/her sole
discretion that special circumstances warrant such modification. If the
Participant dies within the Option Period and prior to the lapse of the Option,
the Option will lapse at the expiration of the Option Period set by the grant
unless it is exercised before such time by the Participant's legal
representative(s) or by the person(s) entitled to do so under the Participant's
Will or, if the Participant fails to make testamentary disposition of the Option
or dies intestate, by the person(s) entitled to receive the Option under the
applicable laws of descent and distribution.

        G.    Individual Limitation.    In the case of an Incentive Stock
Option, the aggregate Fair Market Value of the Stock for which Incentive Stock
Options (whether under this Plan or another arrangement) in any calendar year
are first exercisable will not exceed $100,000 with respect to such calendar
year (or such other individual limit as may be in effect under the Code on the
Date of Grant) plus any unused portion of such limit as the Code may permit to
be carried over.

        9.    Performance Units.

        A.    Performance Units.    One or more Performance Units may be earned
by an Eligible Employee based on the achievement of preestablished performance
objectives during a Performance Period.

        B.    Performance Period and Performance Objectives.    The Plan
Administrator will determine a Performance Period and will determine, no later
than 90 days after the beginning of each Performance Period, the performance
objectives for each Participant's Target Performance Award and the number of
Performance Units subject to each Target Performance Award. Performance
objectives may vary from Participant to Participant and will be based upon such
performance criteria or combination of factors as the Plan Administrator deems
appropriate, which may include, but not be limited to, the performance of the
Participant, Constellation Energy, one or more Subsidiaries, or any combination
thereof. Performance Periods may overlap and Participants may participate
simultaneously with respect to Performance Units for which different Performance
Periods are prescribed.

        If during the course of a Performance Period significant events occur as
determined in the sole discretion of the Plan Administrator which the Plan
Administrator expects to have a substantial effect on a performance objective
during such period, the Plan Administrator may revise such objective.

        C.    Forfeiture or Payout of Award.    As soon as practicable after the
end of each Performance Period, the Plan Administrator will determine whether
the performance objectives and other material terms of the Award were satisfied.
The Plan Administrator's determination of all such matters will be final and
conclusive.

6

--------------------------------------------------------------------------------

        As soon as practicable after the date the Plan Administrator makes the
above determination, the Plan Administrator will determine the Earned
Performance Award for each Participant. Such determination may result in an
increase or decrease in the number of Performance Units payable based upon such
Participant's Target Performance Award, and will be based upon such factors as
the Plan Administrator determines in his/her sole discretion, but including the
Target Performance Award performance objectives.

        In the event a Participant ceases employment during a Performance
Period, the Performance Unit Award is subject to forfeiture or payout as
follows: (a) Termination—the Performance Unit Award is completely forfeited;
(b) Retirement, Disability or death—payout of the Performance Unit Award is
prorated taking into account factors including, but not limited to, service and
the performance of the Participant during the portion of the Performance Period
before employment ceased; or (c) Early Retirement—if at the Participant's
request, the payout or forfeiture of the Performance Unit Award is determined at
the discretion of the Plan Administrator, or if at Constellation Energy's
request, payout of the Performance Unit Award is prorated taking into account
factors including, but not limited to, service and the performance of the
Participant during the portion of the Performance Period before employment
ceased; provided, however, that the Plan Administrator may modify the above if
it determines in his/her sole discretion that special circumstances warrant such
modification.

        D.    Form and Timing of Payment.    Each Performance Unit is payable in
cash or shares of Stock or in a combination of cash and Stock, as determined by
the Plan Administrator in his/her sole discretion. Such payment will be made as
soon as practicable after the Earned Performance Award is determined.

        10.    Stock Appreciation Rights.

        A.    Grants of Stock Appreciation Rights.    Stock Appreciation Rights
may be granted under the Plan in conjunction with an Option either at the Date
of Grant or by amendment or may be separately granted. Stock Appreciation Rights
will be subject to such terms and conditions not inconsistent with the Plan as
the Plan Administrator may impose.

        B.    Right to Exercise; Exercise Period.    A Stock Appreciation Right
issued pursuant to an Option will be exercisable to the extent the Option is
exercisable; both such Stock Appreciation Right and the Option to which it
relates will not be exercisable during the six months following their respective
Dates of Grant except in the event of the Participant's Disability or death. A
Stock Appreciation Right issued independent of an Option will be exercisable
pursuant to such terms and conditions established in the grant. Notwithstanding
such terms and conditions, in the event of a public tender for all or any
portion of the Stock or in the event that any proposal to merge or consolidate
Constellation Energy with another company is submitted to the stockholders of
Constellation Energy for a vote, the Plan Administrator, in his/her sole
discretion, may declare any previously granted Stock Appreciation Right
immediately exercisable.

        C.    Failure to Exercise.    If on the last day of the Option Period,
in the case of a Stock Appreciation Right granted pursuant to an Option, or the
specified Exercise Period, in the case of a Stock Appreciation Right issued
independent of an Option, the Participant has not exercised a Stock Appreciation
Right, then such Stock Appreciation Right will be deemed to have been exercised
by the Participant on the last day of the Option Period or Exercise Period.

        D.    Payment.    An exercisable Stock Appreciation Right granted
pursuant to an Option will entitle the Participant to surrender unexercised the
Option or any portion thereof to which the Stock Appreciation Right is attached,
and to receive in exchange for the Stock Appreciation Right payment (in cash or
Stock or a combination thereof as described below) equal to either of the
following amounts, determined in the sole discretion of the Plan Administrator
at the Date of Grant: (1) the excess of the Fair Market Value of one share of
Stock at the date of exercise over the Option price,

7

--------------------------------------------------------------------------------

times the number of shares called for by the Stock Appreciation Right (or
portion thereof) which is so surrendered, or (2) the excess of the Book Value of
one share of Stock at the date of exercise over the Book Value of one share of
Stock at the Date of Grant of the related Option, times the number of shares
called for by the Stock Appreciation Right. Upon exercise of a Stock
Appreciation Right not granted pursuant to an Option, the Participant will
receive for each Stock Appreciation Right payment (in cash or Stock or a
combination thereof as described below) equal to either of the following
amounts, determined in the sole discretion of the Plan Administrator at the Date
of Grant: (1) the excess of the Fair Market Value of one share of Stock at the
date of exercise over the Fair Market Value of one share of Stock at the Date of
Grant of the Stock Appreciation Right, times the number of shares called for by
the Stock Appreciation Right, or (2) the excess of the Book Value of one share
of Stock at the date of exercise of the Stock Appreciation Right over the Book
Value of one share of Stock at the Date of Grant of the Stock Appreciation
Right, times the number of shares called for by the Stock Appreciation Right.

        The Plan Administrator may direct the payment in settlement of the Stock
Appreciation Right to be in cash or Stock or a combination thereof.
Alternatively, the Plan Administrator may permit the Participant to elect to
receive cash in full or partial settlement of the Stock Appreciation Right,
provided that (i) the Plan Administrator must consent to or disapprove such
election and (ii) unless the Plan Administrator directs otherwise, the election
and the exercise must be made during the period beginning on the 3rd business
day following the date of public release of quarterly or year-end earnings and
ending on the 12th business day following the date of public release of
quarterly or year-end earnings. The value of the Stock to be received upon
exercise of a Stock Appreciation Right shall be the Fair Market Value of the
Stock on the trading day preceding the date on which the Stock Appreciation
Right is exercised. To the extent that a Stock Appreciation Right issued
pursuant to an Option is exercised, such Option shall be deemed to have been
exercised, and shall not be deemed to have lapsed.

        E.    Nontransferable.    A Stock Appreciation Right will not be
transferable by the Participant except by Will or the laws of descent and
distribution and will be exercisable during the Participant's lifetime only by
the Participant or by the Participant's guardian or legal representative.

        F.    Lapse of a Stock Appreciation Right.    A Stock Appreciation Right
will lapse upon the earlier of: (i) 10 years from the Date of Grant; or (ii) at
the expiration of the Exercise Period as set by the grant. If the Participant
ceases employment within the Exercise Period and prior to the lapse of the Stock
Appreciation Right, the Stock Appreciation Right will lapse as follows:
(a) Termination—the Stock Appreciation Right will lapse on the effective date of
the Termination; or (b) Retirement, Early Retirement, or Disability—the Stock
Appreciation Right will lapse at the expiration of the Exercise Period set by
the grant; provided, however, that the Plan Administrator may modify the above
if he/she determines in his/her sole discretion that special circumstances
warrant such modification. If the Participant dies within the Exercise Period
and prior to the lapse of the Stock Appreciation Right, the Stock Appreciation
Right will lapse at the expiration of the Exercise Period set by the grant
unless it is exercised before such time by the Participant's legal
representative(s) or by the person(s) entitled to do so under the Participant's
Will or, if the Participant fails to make testamentary disposition of the Stock
Appreciation Right or dies intestate, by the person(s) entitled to receive the
Stock Appreciation Right under the applicable laws of descent and distribution.

        11.    Dividend Equivalents.

        A.    Grants of Dividend Equivalents.    Dividend Equivalents may be
granted under the Plan in conjunction with an Option or a separately awarded
Stock Appreciation Right, at the Date of Grant or by amendment, without
consideration by the Participant. Dividend Equivalents may also be granted under
the Plan in conjunction with Performance Units, at any time during the
Performance Period, without consideration by the Participant. Dividend
Equivalents will be granted under a Performance-Based Restricted Stock Award in
conjunction with additional shares of Stock issued if Target Performance Award
performance objectives are exceeded.

8

--------------------------------------------------------------------------------

        B.    Payment.    Each Dividend Equivalent will entitle the Participant
to receive an amount equal to the dividend actually paid with respect to a share
of Stock on each dividend payment date from the Date of Grant to the date the
Dividend Equivalent lapses as set forth in Section 11D. The Plan Administrator,
in his/her sole discretion, may direct the payment of such amount at such times
and in such form and manner as determined by the Plan Administrator.

        C.    Nontransferable.    A Dividend Equivalent will not be transferable
by the Participant.

        D.    Lapse of a Dividend Equivalent.    Each Dividend Equivalent will
lapse on the earlier of (i) the date of the lapse of the related Option or Stock
Appreciation Right; (ii) the date of the exercise of the related Option or Stock
Appreciation Right; (iii) the end of the Performance Period (or if earlier, the
date the Participant ceases employment) of the related Performance Units or
Performance-Based Restricted Stock Award; or (iv) the lapse date established by
the Plan Administrator on the Date of Grant of the Dividend Equivalent.

        12.    Accelerated Award Payout/Exercise.

        A.    Change in Control.    Notwithstanding anything in this Plan
document to the contrary, a Participant is entitled to an accelerated payout or
accelerated Option or Exercise Period (as set forth in Section 12B) with respect
to any previously granted Award, upon the happening of a change in control.

        A change in control for purposes of this Section 12 means the occurrence
of any one of the following events:

        (i)    individuals who, on January 24, 2003, constitute the Board (the
"Incumbent Directors") cease for any reason to constitute at least a majority of
the Board, provided that any person becoming a director subsequent to
January 24, 2003, whose election or nomination for election was approved by a
vote of at least two-thirds of the Incumbent Directors then on the Board (either
by a specific vote or by approval of the proxy statement of Constellation Energy
Group (the "Company") in which such person is named as a nominee for director,
without written objection to such nomination) shall be an Incumbent Director;
provided, however, that no individual initially elected or nominated as a
director of the Company as a result of an actual or threatened election contest
with respect to directors or as a result of any other actual or threatened
solicitation of proxies by or on behalf of any person other than the Board shall
be deemed to be an Incumbent Director;

        (ii)    any "person" (as such term is defined in Section 3(a)(9) of the
Securities Exchange Act of 1934, as amended (the "Exchange Act") and as used in
Sections 13(d)(3) and 14(d)(2) of the Exchange Act) is or becomes a "beneficial
owner" (as defined in Rule 13d-3 under the Exchange Act), directly or
indirectly, of securities of the Company representing 20% or more of the
combined voting power of the Company's then outstanding securities eligible to
vote for the election of the Board (the "Company Voting Securities"); provided,
however, that the event described in this paragraph  (ii) shall not be deemed to
be a Change in Control by virtue of any of the following acquisitions: (A) by
the Company or any corporation with respect to which the Company owns a majority
of the outstanding shares of common stock or has the power to vote or direct the
voting of sufficient securities to elect a majority of the directors (a
"Subsidiary Company"), (B) by any employee benefit plan (or related trust)
sponsored or maintained by the Company or any Subsidiary Company, (C) by any
underwriter temporarily holding securities pursuant to an offering of such
securities, (D) pursuant to a Non-Qualifying Transaction (as defined in
paragraph (iii)), or (E) pursuant to any acquisition by Participant or any group
of persons including Participant (or any entity controlled by Participant or any
group of persons including Participant);

        (iii)    Company shareholder approval of a merger, consolidation,
statutory share exchange or similar form of corporate transaction involving the
Company or any of its Subsidiary Companies,

9

--------------------------------------------------------------------------------

whether for such transaction or the issuance of securities in the transaction (a
"Business Combination"), unless immediately following such Business Combination:
(A) more than 60% of the total voting power of (x) the corporation resulting
from such Business Combination (the "Surviving Corporation"), or (y) if
applicable, the ultimate parent corporation that directly or indirectly has
beneficial ownership of at least 95% of the voting securities eligible to elect
directors of the Surviving Corporation (the "Parent Corporation"), is
represented by Company Voting Securities that were outstanding immediately prior
to such Business Combination (or, if applicable, is represented by shares into
which such Company Voting Securities were converted pursuant to such Business
Combination), and such voting power among the holders thereof is in
substantially the same proportion as the voting power of such Company Voting
Securities among the holders thereof immediately prior to the Business
Combination, (B) no person (other than any employee benefit plan (or related
trust) sponsored or maintained by the Surviving Corporation or the Parent
Corporation), is or becomes the beneficial owner, directly or indirectly, of 20%
or more of the total voting power of the outstanding voting securities eligible
to elect directors of the Parent Corporation (or, if there is no Parent
Corporation, the Surviving Corporation) and (C) at least a majority of the
members of the board of directors of the Parent Corporation (or, if there is no
Parent Corporation, the Surviving Corporation) following the consummation of the
Business Combination were Incumbent Directors at the time of the Board's
approval of the execution of the initial agreement providing for such Business
Combination (any Business Combination which satisfies all of the criteria
specified in (A), (B), and (C) above shall be deemed to be a "Non-Qualifying
Transaction"); or

        (iv)    the stockholders of the Company approve a plan of complete
liquidation or dissolution of the Company, or the consummation of a sale of all
or substantially all of the Company's assets.

Notwithstanding the foregoing, a Change in Control of the Company shall not be
deemed to occur solely because any person acquires beneficial ownership of more
than 20% of the Company Voting Securities as a result of the acquisition of
Company Voting Securities by the Company which reduces the number of Company
Voting Securities outstanding; provided, that if after such acquisition by the
Company such person becomes the beneficial owner of additional Company Voting
Securities that increases the percentage of outstanding Company Voting
Securities beneficially owned by such person, a Change in Control of the Company
shall then occur.

        B.    Amount of Award Subject to Accelerated Payout/Option
Period/Exercise Period.    The amount of a Participant's previously granted
Award that will be paid or exercisable upon the happening of a change in control
will be determined as follows:

        Restricted Stock Awards.    The Participant will be entitled to an
accelerated Award payout, and the amount of the payout will be based on the
number of shares of Restricted Stock that were issued on the Date of Grant,
prorated based on the number of months of the restriction period that have
elapsed as of the payout date. Also, with respect to Performance-Based
Restricted Stock Awards, in determining the amount of the payout, maximum
performance achievement will be assumed.

        Stock Option Awards and Stock Appreciation Rights.    Any previously
granted Stock Option Awards or Stock Appreciation Rights will be immediately
exercisable.

        Performance Units.    The Participant will be entitled to an accelerated
Award payout, and the amount of the payout will be based on the number of
Performance Units subject to the Target Performance Award as established on the
Date of Grant, prorated based on the number of months of the Performance Period
that have elapsed as of the payout date, and assuming that maximum performance
was achieved.

        C.    Timing of Accelerated Payout/Option Period/Exercise Period.    The
accelerated payout set forth in Section 12B will be made in cash within 30 days
after the date of the change in control. The

10

--------------------------------------------------------------------------------

accelerated Option Period/Exercise Period set forth in Section 12B will begin on
the date of the change in control, and applicable payments will be in cash. When
Stock is related to the Award, the amount of cash will be determined based on
the Fair Market Value of Stock on the payout or exercise date, whichever is
applicable.

        13.    Amendment of Plan.

        The Plan Administrator may at any time and from time to time alter,
amend, suspend or terminate the Plan in whole or in part, except no such action
may be taken without the consent of the Participant to whom any Award was
previously granted, which adversely affects the rights of such Participant
concerning such Award, except as such termination or amendment of the Plan is
required by statute, or rules and regulations promulgated thereunder.

        14.    Miscellaneous Provisions.

        A.    Nontransferability.    No benefit provided under this Plan shall
be subject to alienation or assignment by a Participant (or by any person
entitled to such benefit pursuant to the terms of this Plan), nor shall it be
subject to attachment or other legal process except (i) to the extent
specifically mandated and directed by applicable state or federal statute,
(ii) as requested by the Participant (or by any person entitled to such benefit
pursuant to the terms of this Plan), and approved by the Plan Administrator, to
satisfy income tax withholding, and (iii) as requested by the Participant and
approved by the Plan Administrator, to members of the Participant's family, or a
trust established by the Participant for the benefit of family members.

        B.    No Employment Right.    Participation in this Plan shall not
constitute a contract of employment between Constellation Energy or any
Subsidiary and any person and shall not be deemed to be consideration for, or a
condition of, continued employment of any person.

        C.    Tax Withholding.    Constellation Energy or a Subsidiary may
withhold any applicable federal, state or local taxes at such time and upon such
terms and conditions as required by law or determined by Constellation Energy or
a Subsidiary. Subject to compliance with any requirements of applicable law, the
Plan Administrator may permit or require a Participant to have any portion of
any withholding or other taxes payable in respect to a distribution of Stock
satisfied through the payment of cash by the Participant to Constellation Energy
or a Subsidiary, the retention by Constellation Energy or a Subsidiary of shares
of Stock, or delivery of previously owned shares of the Participant's Stock,
having a Fair Market Value equal to the withholding amount.

        D.    Fractional Shares.    Any fractional shares concerning Awards
shall be eliminated at the time of payment or payout by rounding down for
fractions of less than one-half and rounding up for fractions of equal to or
more than one-half. No cash settlements shall be made with respect to fractional
shares eliminated by rounding.

        E.    Government and Other Regulations.    The obligation of
Constellation Energy to make payment of Awards in Stock or otherwise shall be
subject to all applicable laws, rules, and regulations, and to such approvals by
any government agencies as may be required. Constellation Energy shall be under
no obligation to register under the Securities Act of 1933, as amended ("Act"),
any of the shares of Stock issued, delivered or paid in settlement under the
Plan. If Stock awarded under the Plan may in certain circumstances be exempt
from registration under the Act, Constellation Energy may restrict its transfer
in such manner as it deems advisable to ensure such exempt status. The Plan is
not subject to any provisions of the Employee Retirement Income Security Act of
1974.

        F.    Indemnification.    The Plan Administrator (and his/her
designees), and Constellation Energy's Chairman of the Board, and President and
all other employees of Constellation Energy or its Subsidiaries whose assigned
duties include matters under the Plan, shall be indemnified by Constellation
Energy or its Subsidiaries or from proceeds under insurance policies purchased
by

11

--------------------------------------------------------------------------------

Constellation Energy or its Subsidiaries against any and all liabilities arising
by reason of any act or failure to act made in good faith pursuant to the
provisions of the Plan, including expenses reasonably incurred in the defense of
any related claim.

        G.    Changes in Capital Structure.    In the event of any change in the
outstanding shares of Stock by reason of any stock dividend or split,
recapitalization, combination or exchange of shares or other similar changes in
the Stock, then appropriate adjustments shall be made in the shares of Stock
theretofore awarded to the Participants and in the aggregate number of shares of
Stock which may be awarded pursuant to the Plan. Such adjustments shall be
conclusive and binding for all purposes. Additional shares of Stock issued as
the result of any such change shall bear the same restrictions as the shares of
Stock to which they relate.

        H.    Constellation Energy Successors.    In the event Constellation
Energy becomes a party to a merger, consolidation, sale of substantially all of
its assets or any other corporate reorganization in which Constellation Energy
will not be the surviving corporation or in which the holders of the Stock will
receive securities of another corporation (in any such case, the "New Company"),
then the New Company shall assume the rights and obligations of Constellation
Energy under this Plan.

        I.    Governing Law.    All matters relating to the Plan or to Awards
granted hereunder shall be governed by the laws of the State of Maryland,
without regard to the principles of conflict of laws.

        J.    Relationship to Other Benefits.    Any Awards under this Plan are
not considered compensation for purposes of determining benefits under any
pension, profit sharing, or other retirement or welfare plan, or for any other
general employee benefit program.

        K.    Expenses.    The expenses of administering the Plan shall be borne
by Constellation Energy and its Subsidiaries.

        L.    Titles and Headings.    The titles and headings of the sections in
the Plan are for convenience of reference only, and in the event of any
conflict, the text of the Plan, rather than such titles or headings, shall
control.

This document constitutes part of a prospectus covering securities that have
been registered under the Securities Act of 1933.

        You may obtain without charge, upon written or oral request, a copy of
documents incorporated by reference in the Registration Statement on file with
the Securities and Exchange Commission pertaining to the securities offered
under the Management Long-Term Incentive Plan. In addition you may obtain,
without charge, upon written or oral request, a copy of documents that are
required to be delivered under Rule 428(b) of the Securities Act including our
annual report to shareholders or annual report on Form 10-K and a copy of the
documents that comprise the prospectus.

        To make a request for any of these documents, you may telephone or
write:

Kathleen A. Chagnon
Corporate Secretary
750 East Pratt Street
18th Floor
Baltimore, Maryland 21202
(410) 783-3600

12

--------------------------------------------------------------------------------

Management Long-Term Incentive Plan
Appendix

Additional Information

        The Plan is not subject to any provisions of the Employee Retirement
Income Security Act of 1974, and the Plan is not qualified under Section 401(a)
of the Internal Revenue Code.

        Participants may obtain additional information about the Plan by
contacting:

Director—Compensation
Constellation Energy Group, Inc.
750 East Pratt Street
5th Floor
Baltimore, MD 21201-2437
(410) 783-2844

        After each grant is made, participants will be furnished with
information about the amount of the grant. At least annually, participants will
be furnished with information about their outstanding grants.

        In general, grants subject to restrictions are taxable to participants
when the restrictions lapse, and deductible by Constellation Energy at such
time, based on the fair market value of the awards when the restrictions lapse.
Grants not subject to restrictions are taxable/deductible at fair market value
on the grant date. Additionally, options are subject to other special tax
provisions.

13

--------------------------------------------------------------------------------

QuickLinks

Constellation Energy Group, Inc. Management Long-Term Incentive Plan (Plan)