CIPSCO Incorporated has two first tier subsidiaries: Central Illinois Public Service Company, an investment subsidiary, and Central Illinois Public Service Company, an electric and gas public utility. CIPSCO Investment Company manages nonutility investments and provides investment management services for affiliates. Central Illinois Public Service Company markets electricty and natural gas in central and southern Illinois. It generates, transmits and distributes electricty and, through interchange agreements with other utility systems, purchases and sells power on a firm basis, in emergency situations or when economical to do so. CIPSCO also sells and distributes natural gas which it purchases from natural gas producers and other suppliers and transports natural gas purchased by end-users directly from suppliers. Electric operations accounted for 81% of 1996 revenues; gas operations, 17% and investments, 2%.