Ameren Illinois Company, D/B/A Ameren Illinois, et al. v. FERC

D.C. Cir. No. 20-1277, et al. Ameren Companies’ recovery of the costs of certain “Materials & Supplies” inventories in their cost-of-service formula rates for interstate electric transmission service.  Midcontinent Ind. Sys. Operator, Inc. & Ameren Ill. Co., Order Accepting Formula Rate Revisions, 171 FERC ¶ 61,090 (2020), reh’g denied by operation of law, 172 FERC ¶ 61,009 (2020); Midcontinent Ind. Sys. Operator, Inc. & Ameren Transmission Co. of Ill., Letter Order, 171 FERC ¶ 61,141 (2020), reh’g denied by operation of law, 172 FERC ¶ 61,010 (2020); Midcontinent Ind. Sys. Operator, Inc. & Union Elec. Co., Letter Order, 171 FERC ¶ 61,140 (2020), reh’g denied by operation of law, 172 FERC ¶ 62,028 (2020); Midcontinent Indep. Sys. Operator, Inc. & Ameren Ill. Co., order on reh’g, 173 FERC ¶ 61,034 (2020).  Order on formal challenge to certain inputs to Ameren Illinois’ formula rate.  Ameren Illinois Co., 174 FERC ¶ 61,209 (2021), order on reh’g, 177 FERC ¶ 61,107 (Nov. 18, 2021).