Ameren is a rate-regulated public utility holding company with three principal operating subsidiaries serving customers in Missouri and Illinois through the generation, transmission, and distribution of electricity, as well as natural gas distribution. The company owns and operates a diversified power generation portfolio including coal, nuclear, renewable energy (hydroelectric, wind, and solar), and natural gas facilities, while its transmission subsidiary operates in the MISO footprint under FERC regulation. Ameren generates revenue through regulated customer rates determined by state public utility commissions and FERC, with recovery mechanisms including annual reconciliations and capital investment trackers, and the company is transitioning its generation mix toward renewables and battery storage while retiring coal plants and planning nuclear expansion to meet long-term customer demand growth.