Ameren Corporation NYSE: AEE was create December 31, 1997 by the merger of Missouri's Union Electric Company (formerly NYSE: UEP) and the neighboring Central Illinois Public Service Company (CIPSCO Inc. holding, formerly NYSE: CIP). It is now a holding company for several power companies and energy companies. The company is based in St. Louis, Missouri. Ameren is a portmanteau for "American" and "Energy".