American Electric Power Company, Inc. is a public utility holding company, which, through directly and indirectly owned subsidiaries, generates, transmits and distributes electricity, natural gas and other commodities. It is one of the largest integrated utilities in the U.S., serving more than 5.5 million customers in multiple states. Its service area covers Arkansas, Indiana, Kentucky, Louisiana, Michigan, Ohio, Oklahoma, Tennessee, Texas, Virginia and West Virginia. The company mainly operates under the following business segments: Vertically Integrated Utility Operations, Transmission & Distribution Utilities, AEP Transmission Holdco, Generation and Marketing. Its public utility subsidiaries are Appalachian Power Company, Indiana Michigan Power Company, Kentucky Power Company, Kingsport Power Company, Ohio Power Company, Public Service Company of Oklahoma, Southwestern Electric Power Company, AEP Texas Central Company, AEP Texas North Company, Wheeling Power Company, etc.