AEP is a public utility holding company that generates, transmits, and distributes electricity to customers across multiple states through vertically integrated subsidiaries, as well as through transmission-only and competitive retail operations. The company operates four main business segments: vertically integrated utilities that own generation capacity fueled by coal, natural gas, nuclear, and renewables; transmission and distribution utilities serving retail and competitive markets; a transmission holding company developing significant new transmission infrastructure; and a generation and marketing business that supplies power to industrial, municipal, and rural customers through both retail supply and wholesale commodity trading. AEP's revenues derive from cost-of-service retail rates regulated by state utility commissions, FERC-regulated wholesale rates, and transmission revenue based on formula-rate filings, supplemented by competitive retail and trading operations in deregulated markets.