What is "exelon"

Exelon Corporation is an American Fortune 150 (#111 in 2015) energy company headquartered in the Chase Tower in the Chicago Loop area of Chicago, Illinois, United States with revenues of approximately $34.5 billion and employing approximately 34,000 employees. Exelon is the largest electric holding company in the United States by revenue, the largest regulated utility in the United States with approximately 10 million customers, and is also the largest operator of nuclear power plants in the United States. It was created in October 2000 by the merger of PECO Energy Company and Unicom, of Philadelphia and Chicago respectively. Unicom owned Commonwealth Edison. Exelon operates regulated utilities in Illinois, Pennsylvania, Maryland, Delaware, New Jersey, and Washington, DC. In October 2009, Exelon had full or majority ownership of 17 nuclear reactors in 10 nuclear power plants. Exelon has operations and business activities in 47 states, the District of Columbia and Canada and is the largest competitive U.S. power generator with approximately 35,000 megawatts of owned capacity. Exelon merged with Constellation Energy Group in March 2012 and acquired Pepco Holdings in March 2016. Exelon consists of eight main operating subsidiaries with Exelon Generation, a deregulated energy generator, Constellation, a deregulated competitive energy supplier, and six regulated utilities, Commonwealth Edison (Illinois), Philadelphia Electric 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).