Exelon Corporation is an American Fortune 100 energy company headquartered in Chicago, Illinois and incorporated in Pennsylvania.[2] It generates revenues of approximately $33.5 billion and employs approximately 33,400 people.[3] Exelon is the largest electric parent company in the United States by revenue, the largest regulated electric utility in the United States with approximately 10 million customers, and was formerly the largest operator of nuclear power plants in the United States and the largest non-governmental operator of nuclear power plants in the world until the generation sources were spun off into an independent company, Constellation Energy, in 2022.[4][5]
Exelon was created in October 2000 by the merger of PECO Energy Company of Philadelphia and Unicom Corp of Chicago, which owned Commonwealth Edison.[6] Exelon operates regulated utilities in Illinois, Pennsylvania, Maryland, Delaware, New Jersey, and Washington, DC. In October 2009, Exelon had full or majority ownership of 23 nuclear reactors in 14 nuclear power plants.[7][8] Exelon has operations and business activities in 48 states, the District of Columbia and Canada, and was formerly the largest competitive U.S. power generator with approximately 35,500 megawatts of owned capacity until the 2022 company separation.[3][9] Exelon merged with Constellation Energy in March 2012 and acquired Pepco Holdings in March 2016.[10][11] Exelon consists of six regulated utilities, Commonwealth Edison (Illinois), PECO Energy Company (Pennsylvania), Baltimore Gas and Electric (Maryland), Delmarva Power & Light (Delaware and Maryland), Atlantic City Electric (New Jersey), and Potomac Electric Power Company (Washington, DC and Maryland).[4][12]