Ameren Illinois Co

ameren.com

Ameren Illinois Company (AILIH) is a regulated electric and natural gas utility that delivers electricity and natural gas to customers in Illinois. It makes money by collecting rates approved by state regulators, charging customers for the delivery of electricity and natural gas across its distribution network. Ameren Illinois is a wholly owned subsidiary of Ameren Corporation, with all of its common stock held by the parent as of June 30, 2025. The company files separately with the SEC as its own registrant, as disclosed in the combined Form 10-K filed February 18, 2026 for the fiscal year ended December 31, 2025. Its operations span regulated electric distribution and natural gas distribution in Illinois, subject to oversight by the Illinois Commerce Commission. The business also administers customer energy-efficiency programs and manages natural gas supply for distribution, as noted in the FY2025 10-K filing. Capital structure is characteristic of regulated utilities: rate-base driven, capital-intensive, and dependent on constructive regulatory outcomes for returns.