EXHIBIT 10 (bb)

AMENDED AND RESTATED  CHANGE IN CONTROL SEVERANCE AGREEMENT

This
amended and restated agreement (the "Agreement") is made as of the 27th day of January, 2006, by and between CONSTELLATION ENERGY GROUP, INC. (the "Company") and John R.
Collins (the "Executive").

WHEREAS,
the Company and the Executive are parties to a Change in Control Severance Agreement dated as of [    ] (the "Original Agreement");

WHEREAS,
the Company and the Executive desire to amend and restate the Original Agreement so that the Original Agreement will be replaced in its entirety with this Agreement;

WHEREAS,
the Company wishes to encourage the orderly succession of management in the event of a Change in Control (as hereinafter defined);

WHEREAS,
the Company desires to maintain a severance benefit for the Executive covering the period from the date of a Change in Control until the end of the twenty-four month
period following the date of a Change in Control, to avoid the loss or the serious distraction of the Executive to the detriment of the Company and its stockholders prior to and during such period
when the Executive's undivided attention and commitment to the needs of the Company would be particularly important; and

WHEREAS,
the Executive desires to devote the Executive's time and energy for the benefit of the Company and its stockholders and not to be distracted as a result of a Change in Control.

NOW,
THEREFORE, the parties agree as follows:

1.Definitions.

1.1Annual Award Amount.The term "Annual Award Amount" means, as of the applicable date of determination, the
average of the two highest annual incentive awards under the Company's annual incentive plan (or the annual incentive plan maintained by a successor Company or a Subsidiary) payable or actually paid
under the terms of such annual incentive plan for the performance year during which the date of determination occurs, and in respect of the last four years to the Executive prior to the date of
determination;provided,however, that (a) if the Executive has not been employed by the Company
or a Subsidiary for a sufficient length of time to have been eligible for payment of at least two annual incentive awards, deemed target award payout shall be used for the one or two years for which
the Executive was not so eligible, except that the maximum payout shall be used for the performance year in which the date of determination occurs; (b) for any year during which an annual
incentive award was paid or is payable to the Executive that was prorated because of less than a year of plan participation, such award shall be annualized, except that for the year in which the date
of determination occurs, the maximum payout shall be used; and (c) for any year during which a guaranteed minimum annual incentive award amount was paid or is payable to the Executive, such
full (not prorated because of less than a full year of plan participation) guaranteed annual incentive amount shall be used for such year.

1.2Board.The term "Board" means the Board of Directors of the Company.

1.3Cause.The term "Cause" means the occurrence of any one or more of the following:



A
termination of the Executive's employment for Cause for purposes of this Agreement shall be effected in accordance with the following procedures. The Company shall give the Executive
written notice ("Notice of Termination for Cause") of its intention to terminate the Executive's employment for Cause, setting forth in reasonable

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detail the specific conduct of the Executive that it considers to constitute Cause and the specific provision(s) of this Agreement on which it relies, and stating the date, time and place of the Board
Meeting for Cause. The "Board Meeting for Cause" means a meeting of the Board at which the Executive's termination for Cause will be considered, that takes place not less than ten (10) and not
more than twenty (20) business days after the Executive receives the Notice of Termination for Cause. The Executive shall be given an opportunity, together with counsel, to be heard at the
Board Meeting for Cause. The Executive's Termination for Cause shall be effective when and if a resolution is duly adopted at the Board Meeting for Cause by a two-thirds vote of the entire
membership of the Board, excluding employee directors, stating that in the good faith opinion of the Board, the Executive is guilty of the conduct described in the Notice of Termination for Cause, and
that conduct constitutes Cause under this Agreement.

Notwithstanding
the foregoing, no event described hereunder shall constitute Cause if such event is a result of an isolated, insubstantial and inadvertent action that is not taken in bad
faith and that is remedied by the Executive within ten (10) days after receipt of the Notice of Termination for Cause by the Executive from the Company.

1.4Change in Control.The term "Change in Control" means the occurrence of any one of the following events:



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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,thatif 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.

1.5Effective Date.The term "Effective Date" means the first date during the term of this Agreement on which a
Change in Control occurs provided that the Executive is employed by the Company or a Subsidiary on such date. Anything in this Agreement to the contrary notwithstanding, if the Executive's employment
with the Company or a Subsidiary has terminated for any reason prior to the first date on which a Change in Control occurs, this Agreement shall be null and void as of the date of such termination of
employment;provided,however, that if it is reasonably demonstrated that such termination
(i) was at the request of a third party who has taken steps reasonably calculated to effect a Change in Control, or (ii) otherwise arose in connection with or anticipation of a Change in
Control, then for all purposes of this Agreement the "Effective Date" shall mean the date immediately prior to the date of such termination.

1.6Eligible to Retire.The term "Eligible to Retire" means an Executive who has met the eligibility
requirements for retirement under any Company or Subsidiary supplemental executive non-qualified defined benefit retirement plan in which the Executive participated immediately prior to
the occurrence of a Qualifying Termination.

1.7Good Reason.The term "Good Reason" means, without the Executive's express written consent, the occurrence
after the Effective Date of any one or more of the following:



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The
Executive's right to terminate employment for Good Reason shall not be affected by the Executive's incapacity due to physical or mental illness. The Executive's continued employment
shall not constitute consent to, or a waiver of rights with respect to, any circumstance constituting Good Reason herein;provided, however, a termination
of employment by the Executive for Good Reason for purposes of this Agreement shall be effectuated by giving the Company written
notice ("Notice of Termination for Good Reason") of the termination, at any time during the Protection Period, setting forth in reasonable detail the specific conduct of the Company that constitutes
Good Reason and the specific provision(s) of this Agreement on which the Executive relied. Unless the parties agree otherwise, a termination of employment by the Executive for Good Reason shall be
effective on the thirtieth (30th) day following the date when the Notice of Termination for Good Reason is given, unless the notice sets forth a later date (which date shall in no event
be later than sixty (60) days after the notice is given);provided,however, that no event
described hereunder shall constitute Good Reason if such event is a result of an isolated, insubstantial and inadvertent action that is not taken in bad faith and that is remedied by the Company
within ten (10) days after receipt of the Notice of Termination for Good Reason by the Company from the Executive. If the Company disputes the existence of Good Reason, the burden of proof is
on the Company to establish that Good Reason does not exist. If the Executive continues to provide services to the Company after one of the events giving rise to Good Reason has occurred, it will be
in no way considered a waiver of the Executive's right to terminate his employment at any time during the Protection Period for Good Reason in connection with such event.

1.8Ineligible to Retire.The term "Ineligible to Retire" means an Executive who has not met the eligibility
requirements for retirement under any Company or Subsidiary supplemental executive non-qualified defined benefit retirement plan in which the Executive participated immediately prior to
the occurrence of a Qualifying Termination.

1.9Qualifying Termination.The term "Qualifying Termination" means



1.10Protection Period.The Term "Protection Period" means the two (2) year period commencing on the
Change in Control and ending on the second anniversary of the Change in Control.

1.11Subsidiary.The term "Subsidiary" means 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.

2.Term of Agreement.The term of this Agreement commences on the date hereof and shall continue until the third annual
anniversary of the date hereof;provided,however, that commencing on the date one year after the date
hereof, and on each annual anniversary of such date (such date and each annual anniversary thereof hereinafter referred to as the "Renewal Date"), the term of this Agreement shall be extended
automatically so as to terminate on the third anniversary of such Renewal Date, unless at least 60 days prior to the Renewal Date the Board affirmatively votes not

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to
so extend the term of this Agreement. Notwithstanding the foregoing, upon a Qualifying Termination, the term of this Agreement shall continue until the Company or its successor shall have fully
performed all of its obligations hereunder with respect to the Executive, with no future performance being possible. This Agreement may be terminated at any time by the Board with the written consent
of the Executive. Notwithstanding the foregoing, this Agreement shall automatically terminate upon cessation of Executive's employment with the Company and its Subsidiaries prior to the Effective
Date.

3.Severance Benefits for an Executive Ineligible to Retire.Upon the occurrence of a Qualifying Termination with respect to
an Executive who is Ineligible to Retire:



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4.Severance Benefits for an Executive Eligible to Retire.Upon the occurrence of a Qualifying
Termination with respect to an Executive who is Eligible to Retire:



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5.Grant of Replacement Options upon a Change in Control.Some or all of the outstanding options to purchase common stock of
the Company outstanding under the Company's equity compensation plans (the "Equity Plans") as of the occurrence of a Change in Control will be cashed-out in accordance with the terms of
the applicable plans in connection with any Change in Control (the "Cashed-Out Options"). As soon as practicable following the occurrence of a Change in Control, the Company shall, subject
to shareholder approval, cause the applicable committee or committees administering the Equity Plans to grant the Executive additional stock options (the "Replacement Options") to purchase common
stock of the Company (or, if the Company is not the surviving entity in connection with a Change in Control, common stock of the surviving entity). The Replacement Options will
(i) be granted on substantially the same terms and conditions as the Cashed-Out Options (including provisions related to the term), (ii) have an exercise price equal to the
greater of (A) the fair market value of the underlying common stock at the time of grant and (B) the exercise price of the Cashed-Out Options to which they relate, as
adjusted to take into account the transaction or transactions that resulted in the Change in Control, (iii) relate to the same number of shares as the Cashed-Out Options (as
adjusted to take into account the transaction or transactions that resulted in the Change in Control), (iv) vest in accordance with the terms of the schedule of the Cashed-Out
Options to which they relate (excluding any vesting that occurs as a result of such Change in Control and, for purposes of determining the vesting schedule, the Replacement Options will be deemed to
have been granted at the time of grant of the Cashed-Out Options to which they relate), and (v) will remain exercisable for the same period as the Cashed-Out Options
would have been exercisable had they not been terminated. The Replacement Options shall vest in full as of a Qualifying Termination. Notwithstanding anything to the contrary set forth herein, the
Replacement Options will not vest in connection with a subsequent transaction (the "Subsequent Transaction") following the Change in Control in which such Replacement Options were granted (the
"Initial Change in Control") that would constitute a Change in Control if such Subsequent Transaction merely increases the percentage ownership of common stock of the Company held by the person or
entity whose initial acquisition of common stock of the Company triggered the Initial Change in Control.

6.Non-Exclusivity of Rights.Nothing in this Agreement shall prevent or limit the Executive's continuing or
future participation in any plan, program, policy or practice provided by the Company or a successor company or a Subsidiary (whichever is the Executive's employer) for which the Executive may
qualify, nor shall anything in this Agreement limit or otherwise affect such rights as the Executive may have under any contract or agreement with the Company or a successor Company or such
Subsidiary. However, if the Executive receives severance benefits under this Agreement, the Executive is not also entitled to any benefit under any other severance plan, program, arrangement or
agreement maintained by the Company or a Subsidiary. Vested benefits and other amounts that the Executive is otherwise entitled to receive under any incentive compensation (including, but not limited
to any restricted stock or stock option agreements), deferred compensation and other benefit programs listed in Section 1.7(d), life insurance coverage, or any other plan, policy, practice or
program of, or any contract or agreement with, the Company or a successor Company or such Subsidiary on or after the date of the Qualifying Termination shall be payable in accordance with the terms of
each such plan, policy, practice, program, contract or agreement, as the case may be, except as explicitly modified by this Agreement.

7.Full Settlement.The Company's obligation to make the payments provided for in, and otherwise to perform its obligations
under, this Agreement shall not be affected by any set-off, counterclaim, recoupment, defense or other claim, right or action that the Company may have against the Executive or others. In
no event shall the Executive be obligated to seek other employment or take any other action by way of mitigation of the amounts payable to the Executive under any of the provisions of this Agreement
and, such amounts shall not be reduced, regardless of whether the Executive obtains other employment.

8.Certain Additional Payments by the Company.



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9.Certain Additional Agreements under Section 409A.



10.Amendment of Agreement.This Agreement may be amended at any time by the Board with the written consent of the Executive.

11.Construction.Wherever any words are used herein in the masculine gender they shall be construed as though they were also
used in the feminine gender in all cases where they would so apply, and wherever any words are used herein in the singular form, they shall be construed as though they were also used in the plural
form in all cases where they would so apply.

12.Governing Law.This Agreement shall be governed by the laws of Maryland.

13.Dispute Resolution.The parties agree that any disputes, claims, complaints or causes of action of any type or kind
(including but not limited to any disputes relating in any way to this Agreement) which the parties may have

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between
themselves shall be resolved by final and binding arbitration using a single arbitrator from the American Arbitration Association pursuant to its then existing commercial arbitration rules.
The arbitration proceedings shall be conducted in Baltimore, Maryland, unless the parties mutually agree in writing to a different location. Prior to presiding over any such dispute, any arbitrator
shall be required to consent in writing that he or she shall reach a final decision within four (4) months after a claim has been filed and within sixty (60) days after final submission.
Any award rendered in the arbitration may be enforced in any court of competent jurisdiction. Pending the resolution of any such claim or dispute, the Executive (and his beneficiaries) shall continue
to receive all payments and benefits due under this Agreement or otherwise, except to the extent that the arbitrators otherwise provide.

14.Successors and Assigns.



15.Director & Officer Insurance and Indemnification.During the Protection Period and, upon a Qualifying Termination,
for so long thereafter as the Executive could be subject to liability, the Company shall keep in place a directors' and officers' liability insurance policy (or policies) providing comprehensive
coverage to the Executive for claims relating to the Executive's service as an employee, officer, or director of the Company, on terms and conditions no less favorable to the Executive (e.g., with
respect to scope, amounts and deductibles) provided to then-existing officers and directors of the Company. The Company shall indemnify the Executive to the fullest extent permitted by the
general laws of the State of Maryland and shall provide indemnification expenses in advance to the extent permitted thereby. The Company will follow the procedures required by applicable law in
determining persons eligible for indemnification and in making indemnification payments and advances. The indemnification and advance of expenses provided by the Company pursuant to this Agreement
shall not be deemed exclusive of any other rights to which the Executive may be entitled under any law (common or statutory), or any agreement, vote of stockholders or disinterested directors or other
provision that is consistent with law, both as to action in his official capacity and as to action in another capacity while holding office or while employed or acting as agent for the Company, shall
continue in respect of all events occurring while the Executive was a director of or employed by the Company after the Executive has ceased to be a director of or employed by the Company, and shall
inure to the benefit of the estate, heirs, executors and administrators of the Executive.

16.Reimbursement of Legal Fees.The Company will pay all reasonable fees and expenses, if any, (including, without
limitation, legal fees and expenses) that are incurred by the Executive to enforce this Agreement and that result from a breach of this Agreement by the Company.

17.Notice.Any notices, requests, demands, or other communications provided for by this Agreement shall be sufficient if in
writing and if sent by registered or certified mail to the Executive at the last address the Executive has filed in writing with the Company, or in the case of the Company, to its principal offices.

18.Severability.The invalidity or unenforceability of any provision of this Agreement shall not affect the validity or
enforceability of any other provision of this Agreement. If any provision of this Agreement shall be held invalid or unenforceable in part, the remaining portion of such provision, together with all
other provisions of this Agreement, shall remain valid and enforceable and continue in full force and effect to the fullest extent consistent with law.

19.Withholding.Notwithstanding any other provision of this Agreement, the Company may withhold from amounts payable under
this Agreement all federal, state, local and foreign taxes that are required to be withheld by applicable laws or regulations.

20.Entire Agreement.Unless otherwise specifically provided in this Agreement, the Executive and the Company acknowledge that
this Agreement supersedes any other agreement between them or between the Executive and the Company or a Subsidiary, concerning the subject matter hereof.

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21.Alienability.The rights and benefits of the Executive under this Agreement may not be anticipated, alienated or subject
to attachment, garnishment, levy, execution or other legal or equitable process except as required by law. Any attempt by the Executive to anticipate, alienate, assign, sell, transfer, pledge,
encumber or charge the same shall be void. Payments hereunder shall not be considered assets of the Executive in the event of insolvency or bankruptcy.

22.Counterparts.This Agreement may be executed in several counterparts, each of which shall be deemed an original, and said
counterparts shall constitute but one and the same instrument.

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IN WITNESS WHEREOF, the Executive has hereunto set the Executive's hand and, pursuant to the authorization of the Board, the Company has caused this Agreement to be executed in its name
on its behalf, all as of the day and year first above written.

| |  | CONSTELLATION ENERGY GROUP, INC. 
| |  | ---------------------------------
| |  | By:                              
| |  | /s/JOHN R. COLLINSJohn R. Collins

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