American Electric Power (AEP) is one of the largest electric utilities in the United States. The company operates in Arkansas, Indiana, Kentucky, Louisiana, Michigan, Ohio, Oklahoma, Tennessee, Texas, Virginia, and West Virginia and serves over 5 million customers. The holding company owns the nation's largest electricity transmission system, a network of almost 39,000 miles and has more than 38,000 MW of largely coal-fired generating capacity. AEP also markets and trades electricity, natural gas, and other commodities and has stakes in independent power plants. In addition, the holding company has operations involved with natural gas transportation, storage, and processing, and barge transportation services.