8-K

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the

Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): March 12, 2012

Commission File Number	Exact name of registrant as specified in its charter	IRS Employer Identification No.
1-12869	CONSTELLATION ENERGY GROUP, INC.	52-1964611

100 CONSTELLATION WAY, BALTIMORE, MARYLAND	21202
(Address of principal executive offices)	(Zip Code)

410-470-2800

(Registrant’s telephone number, including area code)

MARYLAND

(State of Incorporation of registrant)

NOT APPLICABLE

(Former name, former address and former fiscal year, if changed since last report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

¨ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

¨ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

¨ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

¨ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Item 5.04  Temporary Suspension of Trading Under Registrant’s Employee Benefit Plans

Activity in the Constellation Energy Group, Inc. (“Constellation”) Stock Fund under the Constellation Employee Savings Plan, the Represented Employee Savings Plan for Nine Mile Point and the Employee Savings Plan for Constellation Energy Nuclear Group, LLC (collectively, the “401(k) Plans”) will be closed for participant transactions from March 12, 2012 until sometime during the week of March 12, 2012. This blackout period is required by the 401(k) Plans’ recordkeeper, T. Rowe Price, in connection with the closing of the previously announced merger (the “Merger”) with Bolt Acquisition Corporation, a Maryland Corporation (“Merger Sub”) and a wholly-owned subsidiary of Exelon Corporation, a Pennsylvania corporation (“Exelon”), in accordance with the Agreement and Plan of Merger, dated as of April 28, 2011, by and among Constellation, Exelon and Merger Sub.

On March 12, 2012, Constellation provided a notice to its directors and executive officers informing them that, during the blackout period, pursuant to Section 306 of the Sarbanes-Oxley Act of 2002, they will be unable to trade in Constellation’s or Exelon’s common stock (or related securities). All dates contained in the attached notice assume the closing will occur on March 12, 2012, but if the closing does not occur on that date, the attached notice will be updated to reflect the actual date of the closing of the merger. During the blackout period and for a two-year period thereafter, information about the actual beginning and ending dates of the blackout period may be obtained, without charge, by contacting prior to the Merger Constellation Energy, Inc., Attention: Corporate Secretary, 100 Constellation Way, Baltimore, MD 21202 (telephone (410) 470-2800), and after the Merger Exelon Corporation, Attention: Corporate Secretary, 10 South Dearborn Street, P.O. Box 805379, Chicago, IL 60680 (telephone (312) 394-7398).

Constellation was unable to provide advance notice of the blackout period due to events that were unforeseeable to, and circumstances that were beyond the reasonable control of, Constellation as determined in writing by the administrator of the 401(k) Plans. A copy of this written determination accompanied the blackout notice provided to Constellation’s directors and executive officers.

A copy of the blackout notice sent to Constellation’s directors and executive officers is attached hereto as Exhibit 99.1 and is incorporated herein by reference.

* * * * *

Item 9.01. Financial Statements and Exhibits

(d) Exhibits

Exhibit No.	Description
99.1	Blackout Notice to Directors and Executive Officers.

SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934 each registrant has duly caused this report to be signed on its behalf by the undersigned, hereunto duly authorized.

	CONSTELLATION ENERGY GROUP, INC.
	(Registrant)
Date: March 12, 2012	/s/ Sean J. Klein
	Sean J. Klein
	Assistant Secretary

EXHIBIT INDEX

Exhibit No.	Description
99.1	Blackout Notice to Directors and Executive Officers.

EX-99.1

Exhibit 99.1

Constellation Energy Group, Inc.

Notice to Directors and Executive Officers

Activity in the Constellation Energy Stock Fund under the Constellation Energy Employee Savings Plan, the Represented Employee Savings Plan for Nine Mile Point and the Employee Savings Plan for Constellation Energy Nuclear Group, LLC (collectively, the “401(k) Plans”) will be closed for participant transactions from March 12, 2012 until sometime during the week of March 12, 2012.

This temporary suspension is required by the 401(k) Plans’ recordkeeper, T. Rowe Price, in connection with the expected closing of the merger with Exelon Corporation on March 12, 2012. This notice is intended to inform you that, pursuant to Section 306 of the Sarbanes-Oxley Act of 2002, during the blackout period you will be unable to trade in Constellation Energy or Exelon common stock (or related securities). Please note that this restriction will not apply to certain trading activities, including (i) the sale of shares to pay taxes upon the grant or vesting of an equity award and (ii) dividend reinvestments. If the closing does not occur by March 12, 2012, you will be provided with updated information regarding the actual date of the closing.

Constellation Energy was unable to provide advance notice of the blackout period due to events that were unforeseeable to, and circumstances that were beyond the reasonable control of, Constellation Energy as determined in writing by the administrator of the 401(k) Plans. A copy of this written determination accompanies this blackout notice.

If you have any questions about this notice or the required trading restriction, including whether the blackout period has begun or ended, you may obtain information, without charge, by contacting prior to the merger Constellation Energy, Inc., Attention: Corporate Secretary, 100 Constellation Way, Baltimore, MD 21202 (telephone (410) 470-2800), and after the merger Exelon Corporation, Attention: Corporate Secretary, 10 South Dearborn Street, P.O. Box 805379, Chicago, IL 60680 (telephone (312) 394-7398).

MEMORANDUM

To whom it may concern:

I understand that generally, pursuant to ERISA Section 101(i), a 30-day advance notice of any blackout period in an individual account plan must be provided. ERISA Section 101(i)(2)(C) provides an exception to the general rule where the timing of blackout is caused by circumstances beyond the reasonable control of the Plan Administrator.

Constellation Energy Group, Inc. and Exelon Corp. entered in the Agreement and Plan of Merger By and Among Exelon Corporation, Bolt Acquisition Corporation and Constellation Energy Group, Inc. dated as of April 28, 2011. The closing of the transaction contemplated by that agreement is contingent on receipt of a series of regulatory approvals projected for late winter or early spring. In anticipation of the pending merger, the Constellation Energy Group, Inc. Employee Savings Plan (the “Plan”) sent a notice to all participants on December 14, 2011, describing the pending transaction, the effects it would have on participant accounts, and stating that a blackout period would occur around the close of this transaction.

I hereby certify in writing, as required by 29 CFR §2520.101-3(b)(2)(ii)(B), that due to the uncertain nature of the date of the close of above-referenced transaction, the Plan was unable to provide 30 days’ notice of the blackout period, which will take effect on the date of the close of the above-referenced transaction, and which will continue for a period of 4 business days.

Further, due to the short duration of the blackout period, the Plan will be unable to provide a written notice to participants before the blackout period expires. The Plan will, however, provide notice posted on the recordkeeper’s participant web site, and an electronic mail message will be sent to all active plan participants through the plan sponsor’s electronic mail system. This notice shall be in the form set forth in 29 CFR §2520.101-3(e) titled, “Model Notice.”

/s/ Marcia B. Behlert 3/9/12

Marcia B. Behlert

Plan Administrator