- Business
- Ameren Illinois Company (AILIM), a subsidiary of St. Louis-based Ameren Corporation, operates as a regulated utility providing electric transmission, electric distribution, and natural gas distribution services to approximately 1.2 million electric customers and 816,000 natural gas customers across central and southern Illinois, spanning 43,700 square miles in 89 counties. Founded in 1902 and headquartered in Collinsville, Illinois, the company maintains extensive infrastructure including 4,600 miles of electric transmission lines, 46,000 miles of distribution lines, 1,500 electric substations, over 1.3 million power poles, and 18,300 miles of natural gas transmission and distribution mains supported by 12 underground storage fields with 25 billion cubic feet capacity. It delivers safe, reliable energy to residential, commercial, and industrial customers through rate-regulated operations segmented into Ameren Illinois Electric Distribution, Ameren Illinois Natural Gas, and Ameren Illinois Transmission, while investing in smart grid technology, energy efficiency programs offering rebates and incentives for appliances and insulation, and storm-hardening initiatives. Recent developments include the Illinois Commerce Commission's approval of a four-year integrated grid plan under the Climate and Equitable Jobs Act to enhance reliability; a $350 million investment in the Fairport-Denny-Iowa/Missouri Border transmission project for grid reliability and renewable integration; pricing of first mortgage bonds due 2055 and other debt offerings for infrastructure funding; and a $38 million settlement approved in 2025 providing bill credits to residential and small business customers following an electricity price-fixing resolution.