American Electric Power (AEP) takes its slice of the US power pie out of Middle America. The holding company is one of the largest power generators and distributors in the US. AEP owns the nation's largest electricity transmission system, a network of more than 40,000 miles. It also has 223,000 miles of distribution lines. Its electric utilities have 5.4 million customers in 11 states and have about 31,000 MW of largely coal-fired generating capacity. AEP is a top wholesale energy company; it markets electricity in the US. To raise cash, in 2015 the company sold its commercial barging operations that transported liquids, coal, and dry bulk commodities on the Ohio, Illinois, and lower Mississippi Rivers.