Exelon Corporation, incorporated on February 4, 1999, is a utility services holding company. The company, through its subsidiary, Exelon Generation Company, LLC (Generation), is engaged in the energy generation business. The company, through its subsidiaries, Commonwealth Edison Company (ComEd), PECO Energy Company (PECO), Baltimore Gas and Electric Company (BGE), Pepco Holdings LLC (PHI), Potomac Electric Power Company (Pepco), Delmarva Power & Light Company (DPL) and Atlantic City Electric Company (ACE), is engaged in the energy delivery businesses. The company operates through 12 Segments: Generation's six Segments: Mid-Atlantic, Midwest, New England, New York, ERCOT and Other Power Regions; ComEd; PECO; BGE, and PHI's three utility Segments: Pepco, DPL, and ACE. Generation, ComEd, PECO, BGE, Pepco, DPL and ACE participate in energy markets that are administered by regional transmission organizations (RTOs) and independent system operators (ISOs).