Chicago-based, Exelon Corporation, is a public utility holding company that operates, through its subsidiaries, three business units: Exelon Energy Delivery, which serves over 3.4m electricity customers in Northern Illinois through ComEd, and around 1.5m electricity and 430,000 natural gas customers in Southeastern Pennsylvania through PECO Energy; Exelon Generation, one of the world’s largest power producers and wholesale marketers; and Exelon Enterprises, a collection of businesses that compete across America in the energy supply, infrastructure services, integrated communications, thermal technologies, energy-efficient offerings, turnkey solutions and capital funding industries.