Ameren is a Fortune 500 company that trades on the New York Stock Exchange under the symbol AEE. Ameren Missouri ranks as the largest electric power provider in Missouri, and Ameren Illinois ranks as Illinois' third largest natural gas distribution operation in total number of customers. Employing more than 9,000 personnel, Ameren powers the quality of life for 2.4 million electric customers and more than 900,000 natural gas customers.