Sec Form 4 Filing - Thayer Jonathan W @ EXELON CORP - 2013-05-01

FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person Thayer Jonathan W 2. Issuer Name and Ticker or Trading Symbol EXELON CORP [ EXC] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner X __ Officer (give title below) _____ Other (specify below) EVP and CFO (Last) (First) (Middle) 10 SOUTH DEARBORN STREET, 54TH FLOOR 3. Date of Earliest Transaction (MM/DD/YY) 05/01/2013 (Street) CHICAGO, IL60603 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) __ X __ Form filed by One Reporting Person _____ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Common Stock 05/01/2013 M( 1 ) 5,542 A $ 30.98 18,143 ( 2 ) D Common Stock 05/01/2013 S( 1 ) 5,542 D $ 37 12,601 D Common Stock- 401k Plan Shares 1,558 ( 3 ) I by 401k Plan

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned ( e.g. , puts, calls, warrants, options, convertible securities) 1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5) 6. Date Exercisable and Expiration Date (MM/DD/YY) 7. Title and Amount of Underlying Securities (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4) Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares NQ Stock Option Granted 05/02/2003 $ 30.98 05/01/2013 M( 1 ) 5,542 ( 4 ) ( 4 ) Common Stock 5,542 ( 4 ) 0 D

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Thayer Jonathan W 10 SOUTH DEARBORN STREET 54TH FLOOR CHICAGO, IL60603 EVP and CFO Signatures Scott N. Peters, Attorney in Fact for Jonathan W. Thayer 05/02/2013 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Exercise and sale made pursuant to a Rule 10b5-1 Sales Plan entered into on February 20, 2013. ( 2 )Balance includes 149 shares acquired on March 8, 2013 through automatic dividend reinvestment. ( 3 )Shares held as of April 30, 2013 in a multi-fund 401(k) Plan to be settled in cash upon the reporting person's termination of employment for any reason on a 1:1 basis. Shares are acquired through regular periodic contributions, company matching contributions, and the automatic reinvestment of dividends. ( 4 )Non qualified employee stock options originally granted by Constellation Energy Group, Inc. ("Constellation") that vested and were converted pursuant to the Agreement and Plan of Merger (the "Merger") between Exelon Corporation ("Exelon"), Bolt Acquisition Corporation and Constellation. Each Constellation option was converted into an option to purchase Exelon common stock at the rate of 0.93 shares of Exelon common stock for each share of Constellation common stock at a strike price equal to the quotient of the original Constellation strike price and 0.93.

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).

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