Long-Term Debt And Equity Financings	9 Months Ended
Sep. 30, 2026
Long-Term Debt And Equity Financings [Abstract]
LONG-TERM DEBT AND EQUITY FINANCINGS	LONG-TERM DEBT AND EQUITY FINANCINGS Ameren For the three and nine months ended September 30, 2026, Ameren issued a total of 0.1 million and 0.3 million shares of common stock under its DRPlus and 401(k) plan, and received proceeds of $2 million and $24 million, respectively. As of September 30, 2026, Ameren had a receivable of $6 million related to issuances of common stock under its DRPlus and 401(k) plan. In addition, in the first quarter of 2026, Ameren issued 0.2 million shares of common stock valued at $25 million upon the settlement of stock-based compensation awards. In May 2026, Ameren filed a Form S-3 registration statement with the SEC, registering the offering of 1.9 million shares of its common stock under the DRPlus, which expires in May 2029. Shares of common stock sold under the DRPlus are, at Ameren’s option, newly issued shares, treasury shares, or shares purchased in the open market or in privately negotiated contracts. In August 2026, Ameren, Ameren Missouri, and Ameren Illinois filed a Form S-3 shelf registration statement with the SEC, registering the issuance of an unspecified amount of certain types of securities. This registration statement expires in August 2029. Ameren has entered into an equity distribution sales agreement pursuant to which Ameren may offer and sell from time to time its common stock through an ATM program, which includes the ability to enter into forward sale agreements. In August 2026, Ameren increased the amount of common stock available for sale under the ATM program by $2 billion to a total of $5 billion. There were no shares issued under the ATM program during the nine months ended September 30, 2026. As of September 30, 2026, Ameren had approximately $2 billion of common stock remaining available for sale under the ATM program. Forward sale agreements for 13 million shares outstanding under the ATM program as of September 30, 2026, can be settled at Ameren’s discretion on or prior to dates ranging from January 19, 2028, to March 8, 2028. The initial forward sale price for the agreements ranged from $104.39 to $112.91, with an average initial forward sale price of $109.51. Additionally in May 2025, Ameren entered into forward sale agreements separate from the ATM program with multiple counterparties relating to 6.4 million shares of common stock. The forward sale agreements can be settled at Ameren’s discretion on or prior to January 15, 2027, and the initial forward sale price under these agreements was $91.89 per share. On a settlement date or dates, if Ameren elects to physically settle a forward sale agreement, Ameren will issue shares of common stock to the counterparties at the then-applicable forward sale price. Each initial forward sale price is subject to adjustment based on a floating interest rate factor equal to the overnight bank funding rate less a spread of 75 basis points, and will be subject to decrease on certain dates specified in the forward sale agreements by specified amounts related to expected dividends on shares of the common stock during the term of the forward sale agreements. If the overnight bank funding rate is less than or more than the spread on any day, the interest rate factor will result in a reduction or an increase, respectively, of the forward sale price. The forward sale agreements will be physically settled unless Ameren elects to settle in cash or to net share settle. At September 30, 2026, Ameren could have settled the forward sale agreements with physical delivery of 19.4 million shares of common stock to the respective counterparties in exchange for cash of $2 billion. Alternatively, the forward sale agreements could have also been net settled at September 30, 2026, with the counterparties delivering approximately $80 million of cash or approximately 0.8 million shares of common stock to Ameren. In connection with the forward sale agreements outstanding at September 30, 2026, the various counterparties, or their affiliates, borrowed from third parties and sold 19.4 million shares of common stock. The gross sales price of these shares totaled $2 billion. Ameren does not receive any proceeds from such sales of borrowed shares. The forward sale agreements have been classified as equity transactions. In October 2026, Ameren entered into forward sale agreements under the ATM program for 2.1 million shares of common stock. The October 2026 forward sales can be settled at Ameren’s discretion in or prior to March 2028. The average forward sale price was initially $99.59 for the October 2026 forward sale agreements. In March 2026, Ameren (parent) issued $400 million of 5.00% senior unsecured notes due May 2036, with interest payable semiannually on May 15 and November 15 of each year, beginning November 15, 2026. Net proceeds from this issuance were used to repay a portion of Ameren’s short-term debt, including short-term debt incurred to refinance $350 million of 3.65% senior unsecured notes that matured in February 2026. In September 2026, Ameren (parent) issued $900 million of junior subordinated notes due March 2057, with interest payable semiannually on March 15 and September 15 of each year, beginning March 15, 2027. Net proceeds from this issuance were used for general corporate purposes, including repayment of short-term debt. The junior subordinated notes will initially pay interest at a fixed annual rate of 6.45% until March 15, 2032. After that date, the interest rate will be reset every five years to the applicable five-year United States Treasury rate plus 1.868%, subject to a minimum rate of 6.45%. In 2026, Ameren (parent) purchased first mortgage bonds issued by Ameren Missouri for $16 million. On a consolidated basis, Ameren (parent)’s repurchase of these first mortgage bonds was accounted for as a debt extinguishment and resulted in a pre-tax gain of $4 million, which is reflected in “Other Income, Net” on Ameren’s consolidated statement of income. Ameren Missouri In February 2026, Ameren Missouri issued $450 million of 4.80% first mortgage bonds due March 2036 and $450 million of 5.55% first mortgage bonds due March 2056. Interest is payable semiannually for both issuances on March 15 and September 15 of each year, beginning September 15, 2026. Net proceeds from the February 2026 issuances were used for capital expenditures and to repay short-term debt. In June 2026, Ameren Missouri issued $500 million of 5.75% first mortgage bonds due September 2056, with interest payable semiannually on March 15 and September 15 of each year, beginning March 15, 2027. Net proceeds from this issuance were used to repay short-term debt. Ameren Missouri received capital contributions totaling $125 million and $550 million, respectively, during the three and nine months ended September 30, 2026. Ameren Illinois In August 2026, Ameren Illinois issued $400 million of 5.50% first mortgage bonds due September 2036, with interest payable semiannually on March 15 and September 15 of each year, beginning March 15, 2027. Net proceeds from this issuance were used to repay short-term debt. ATXI In August 2026, pursuant to a note purchase agreement, ATXI issued $140 million of 5.83% senior unsecured notes due August 2041, with interest payable semiannually on February 6 and August 6 of each year, beginning February 6, 2027, through a private placement offering exempt from registration under the Securities Act of 1933, as amended. Net proceeds from this issuance were used to repay short-term debt. In August 2026, pursuant to a note purchase agreement, ATXI agreed to issue $160 million of 6.24% senior unsecured notes due January 2054, with interest payable semiannually on January 28 and July 28 of each year, beginning July 28, 2027, through a private placement offering exempt from registration under the Securities Act of 1933, as amended. ATXI expects to issue the notes and receive the proceeds in January 2027, which will be used to repay short-term debt. Indenture Provisions and Other Covenants See Note 5 – Long-term Debt and Equity Financings under Part II, Item 8, of the Form 10-K for a description of our indenture provisions and other covenants, as well as restrictions on the payment of dividends. At September 30, 2026, the Ameren Companies were in compliance with the provisions and covenants contained in their indentures and articles of incorporation, as applicable, and ATXI was in compliance with the provisions and covenants contained in its note purchase agreements. Off-balance-sheet Arrangements At September 30, 2026, none of the Ameren Companies had any material off-balance-sheet financing arrangements, other than their investment in unconsolidated variable interest entities, letters of credit, and the forward sale agreements relating to common stock. See Note 1 – Summary of Significant Accounting Policies for further detail concerning variable interest entities.

For the three and nine months ended September 30, 2026, Ameren issued a total of 0.1 million and 0.3 million shares of common stock under its DRPlus and 401(k) plan, and received proceeds of $2 million and $24 million, respectively. As of September 30, 2026, Ameren had a receivable of $6 million related to issuances of common stock under its DRPlus and 401(k) plan. In addition, in the first quarter of 2026, Ameren issued 0.2 million shares of common stock valued at $25 million upon the settlement of stock-based compensation awards.

In May 2026, Ameren filed a Form S-3 registration statement with the SEC, registering the offering of 1.9 million shares of its common stock under the DRPlus, which expires in May 2029. Shares of common stock sold under the DRPlus are, at Ameren’s option, newly issued shares, treasury shares, or shares purchased in the open market or in privately negotiated contracts.

Ameren has entered into an equity distribution sales agreement pursuant to which Ameren may offer and sell from time to time its common stock through an ATM program, which includes the ability to enter into forward sale agreements. In August 2026, Ameren increased the amount of common stock available for sale under the ATM program by $2 billion to a total of $5 billion. There were no shares issued under the ATM program during the nine months ended September 30, 2026. As of September 30, 2026, Ameren had approximately $2 billion of common stock remaining available for sale under the ATM program.

Forward sale agreements for 13 million shares outstanding under the ATM program as of September 30, 2026, can be settled at Ameren’s discretion on or prior to dates ranging from January 19, 2028, to March 8, 2028. The initial forward sale price for the agreements ranged from $104.39 to $112.91, with an average initial forward sale price of $109.51. Additionally in May 2025, Ameren entered into forward sale agreements separate from the ATM program with multiple counterparties relating to 6.4 million shares of common stock. The forward sale agreements can be settled at Ameren’s discretion on or prior to January 15, 2027, and the initial forward sale price under these agreements was $91.89 per share. On a settlement date or dates, if Ameren elects to physically settle a forward sale agreement, Ameren will issue shares of common stock to the counterparties at the then-applicable forward sale price. Each initial forward sale price is subject to adjustment based on a floating interest rate factor equal to the overnight bank funding rate less a spread of 75 basis points, and will be subject to decrease on certain dates specified in the forward sale agreements by specified amounts related to expected dividends on shares of the common stock during the term of the forward sale agreements. If the overnight bank funding rate is less than or more than the spread on any day, the interest rate factor will result in a reduction or an increase, respectively, of the forward sale price. The forward sale agreements will be physically settled unless Ameren elects to settle in cash or to net share settle.

At September 30, 2026, Ameren could have settled the forward sale agreements with physical delivery of 19.4 million shares of common stock to the respective counterparties in exchange for cash of $2 billion. Alternatively, the forward sale agreements could have also been net settled at September 30, 2026, with the counterparties delivering approximately $80 million of cash or approximately 0.8 million shares of common stock to Ameren. In connection with the forward sale agreements outstanding at September 30, 2026, the various counterparties, or their affiliates, borrowed from third parties and sold 19.4 million shares of common stock. The gross sales price of these shares totaled $2 billion. Ameren does not receive any proceeds from such sales of borrowed shares. The forward sale agreements have been classified as equity transactions.

In March 2026, Ameren (parent) issued $400 million of 5.00% senior unsecured notes due May 2036, with interest payable semiannually on May 15 and November 15 of each year, beginning November 15, 2026. Net proceeds from this issuance were used to repay a portion of Ameren’s short-term debt, including short-term debt incurred to refinance $350 million of 3.65% senior unsecured notes that matured in February 2026.

In September 2026, Ameren (parent) issued $900 million of junior subordinated notes due March 2057, with interest payable semiannually on March 15 and September 15 of each year, beginning March 15, 2027. Net proceeds from this issuance were used for general corporate purposes, including repayment of short-term debt. The junior subordinated notes will initially pay interest at a fixed annual rate of 6.45% until March 15, 2032. After that date, the interest rate will be reset every five years to the applicable five-year United States Treasury rate plus 1.868%, subject to a minimum rate of 6.45%.

In 2026, Ameren (parent) purchased first mortgage bonds issued by Ameren Missouri for $16 million. On a consolidated basis, Ameren (parent)’s repurchase of these first mortgage bonds was accounted for as a debt extinguishment and resulted in a pre-tax gain of $4 million, which is reflected in “Other Income, Net” on Ameren’s consolidated statement of income.

In February 2026, Ameren Missouri issued $450 million of 4.80% first mortgage bonds due March 2036 and $450 million of 5.55% first mortgage bonds due March 2056. Interest is payable semiannually for both issuances on March 15 and September 15 of each year, beginning September 15, 2026. Net proceeds from the February 2026 issuances were used for capital expenditures and to repay short-term debt.

In August 2026, pursuant to a note purchase agreement, ATXI issued $140 million of 5.83% senior unsecured notes due August 2041, with interest payable semiannually on February 6 and August 6 of each year, beginning February 6, 2027, through a private placement offering exempt from registration under the Securities Act of 1933, as amended. Net proceeds from this issuance were used to repay short-term debt.

In August 2026, pursuant to a note purchase agreement, ATXI agreed to issue $160 million of 6.24% senior unsecured notes due January 2054, with interest payable semiannually on January 28 and July 28 of each year, beginning July 28, 2027, through a private placement offering exempt from registration under the Securities Act of 1933, as amended. ATXI expects to issue the notes and receive the proceeds in January 2027, which will be used to repay short-term debt.

See Note 5 – Long-term Debt and Equity Financings under Part II, Item 8, of the Form 10-K for a description of our indenture provisions and other covenants, as well as restrictions on the payment of dividends. At September 30, 2026, the Ameren Companies were in compliance with the provisions and covenants contained in their indentures and articles of incorporation, as applicable, and ATXI was in compliance with the provisions and covenants contained in its note purchase agreements.

At September 30, 2026, none of the Ameren Companies had any material off-balance-sheet financing arrangements, other than their investment in unconsolidated variable interest entities, letters of credit, and the forward sale agreements relating to common stock. See Note 1 – Summary of Significant Accounting Policies for further detail concerning variable interest entities.