Ameren

Ameren Corporation is an American power company created December 31, 1997, by the merger of Union Electric Company of St. Louis, Missouri and the neighboring Central Illinois Public Service Company of Springfield, Illinois. It is now a holding company for several power companies and energy companies. The company is based in St. Louis, with 2.4 million electric, and 900,000 natural gas customers across 64,000 square miles in central and eastern Missouri and the southern four-fifths of Illinois by area.