Ameren Missouri files request with state regulators to adjust rates next summerST. LOUIS, July 1, 2024 /PRNewswire/ -- On June 28, Ameren Missouri filed with the Missouri Public Service Commission (PSC) a request to adjust its electric base rates next summer. The new rates would take effect in mid-2025 to recover the costs of major electric system upgrades as well as cleaner electricity generation investments to ensure the system remains reliable and resilient for customers. "The grid and generation upgrade ...