Constellation is a leading competitive retail supplier of power, natural gas and energy products and services for homes and businesses across the continental United States. Constellation's family of retail businesses serves approximately 2.2 million residential, public sector and business customers, including more than two-thirds of the Fortune 100. Baltimore-based Constellation is a subsidiary of Exelon Corporation (EXC), the nation's leading competitive energy provider, with 2015 revenues of approximately $34.5 billion, and more than 32,700 megawatts of owned capacity comprising one of the nation's cleanest and lowest-cost power generation fleets.