PECO, formerly the Philadelphia Electric Company, is an energy company founded in 1881 and incorporated in 1929. It became part of Exelon Corporation in 2000 when it merged with Commonwealth Edison's holding company Unicom Corp.

Exelon Corporation is a public utility headquartered in Chicago, and incorporated in Pennsylvania. Exelon is the largest electric parent company in the United States by revenue and is the largest regulated electric utility in the United States with approximately 10 million customers. The company is ranked 99th on the Fortune 500.