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Commission File Number 001-16169 333-85496 001-01839 000-16844 001-01910 001-31403 001-01072 001-01405 001-03559 UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON , D.C. 20549 FORM 10 - K > ANNUAL REPORT PURSUANT TO SECTION 13 OR 15 ( d ) OF THE SECURITIES EXCHANGE ACT OF 1934 For the Fiscal Year Ended December 31 , 2020 or TRANSITION REPORT PURSUANT TO SECTION 13 OR 15 ( d ) OF THE SECURITIES EXCHANGE ACT OF 1934 Name of Registrant ; State or Other Jurisdiction of Incorporation ; Address of Principal Executive Offices ; and Telephone Number EXELON CORPORATION ( a Pennsylvania corporation ) 10 South Dearborn Street P.O. Box 805379 Chicago , Illinois 60680-5379 ( 800 ) 483-3220 EXELON GENERATION COMPANY , LLC ( a Pennsylvania limited liability company ) 300 Exelon Way Kennett Square , Pennsylvania 19348-2473 ( 610 ) 765-5959 COMMONWEALTH EDISON COMPANY ( an Illinois corporation ) 440 South LaSalle Street Chicago , Illinois 60605-1028 ( 312 ) 394-4321 PECO ENERGY COMPANY ( a Pennsylvania corporation ) P.O. Box 8699 2301 Market Street Philadelphia , Pennsylvania 19101-8699 ( 215 ) 841-4000 BALTIMORE GAS AND ELECTRIC COMPANY ( a Maryland corporation ) 2 Center Plaza 110 West Fayette Street Baltimore , Maryland 21201-3708 ( 410 ) 234-5000 PEPCO HOLDINGS LLC ( a Delaware limited liability company ) 701 Ninth Street , N.W. Washington , District of Columbia 20068 ( 202 ) 872-2000 POTOMAC ELECTRIC POWER COMPANY ( a District of Columbia and Virginia corporation ) 701 Ninth Street , N.W. Washington , District of Columbia 20068 ( 202 ) 872-2000 DELMARVA POWER & LIGHT COMPANY ( a Delaware and Virginia corporation ) 500 North Wakefield Drive Newark , Delaware 19702 ( 202 ) 872-2000 ATLANTIC CITY ELECTRIC COMPANY ( a New Jersey corporation ) 500 North Wakefield Drive Newark , Delaware 19702 ( 202 ) 872-2000 IRS Employer Identification Number 23-2990190 23-3064219 36-0938600 23-0970240 52-0280210 52-2297449 53-0127880 51-0084283 21-0398280