Ameren AEE · USD

SEGMENT INFORMATIONAmeren has four segments: Ameren Missouri, Ameren Illinois Electric Distribution, Ameren Illinois Natural Gas, and Ameren Transmission. The Ameren Missouri segment includes all of the operations of Ameren Missouri. Ameren Illinois Electric Distribution consists of the electric distribution business of Ameren Illinois. Ameren Illinois Natural Gas consists of the natural gas business of Ameren Illinois. Ameren Transmission primarily consists of the aggregated electric transmission businesses of Ameren Illinois and ATXI. The category called Other primarily includes Ameren (parent) activities and Ameren Services.Ameren Missouri has one segment. Ameren Illinois has three segments: Ameren Illinois Electric Distribution, Ameren Illinois Natural Gas, and Ameren Illinois Transmission. See Note 1 – Summary of Significant Accounting Policies for additional information regarding the operations of Ameren Missouri, Ameren Illinois, and ATXI.Segment operating revenues and a majority of operating expenses are directly recognized and incurred by Ameren Illinois in each Ameren Illinois segment. Common operating expenses, miscellaneous income and expenses, interest charges, and income tax expense are allocated by Ameren Illinois to each Ameren Illinois segment based on certain factors, which primarily relate to the nature of the cost. Additionally, Ameren Illinois Transmission earns revenue from transmission service provided to Ameren Illinois Electric Distribution, other retail electric suppliers, and wholesale customers. The transmission expense for Illinois customers who have elected to purchase their power from Ameren Illinois is recovered through a cost recovery mechanism with no net effect on Ameren Illinois Electric Distribution earnings, as costs are offset by corresponding revenues. Transmission revenues from these transactions are reflected in Ameren Transmission’s and Ameren Illinois Transmission’s operating revenues. An intersegment elimination at Ameren and Ameren Illinois occurs to eliminate these transmission revenues and expenses.The CODMs for Ameren, Ameren Missouri, and Ameren Illinois are the Chief Executive Officer of Ameren, the Group President of Ameren Utilities of Ameren, and the Chief Financial Officer of Ameren. The CODMs use net income to evaluate income generated from the segments to make decisions about resources allocated to each segment and assess segment performance.

COMMITMENTS AND CONTINGENCIESWe are involved in legal, tax, and regulatory proceedings before various courts, regulatory commissions, authorities, and governmental agencies with respect to matters that arise in the ordinary course of business, some of which involve substantial amounts of money. We believe that the final disposition of these proceedings, except as otherwise disclosed in the notes to our financial statements, will not have a material adverse effect on our results of operations, financial position, or liquidity.See also Note 1 – Summary of Significant Accounting Policies, Note 2 – Rate and Regulatory Matters, Note 9 – Callaway Energy Center, Note 13 – Related-party Transactions, and Note 15 – Supplemental Information in this report.Environmental MattersOur electric generation, transmission, and distribution and natural gas distribution and storage operations must comply with a variety of statutes and regulations relating to the protection of the environment and human health and safety, including permitting programs implemented by federal, state, and local authorities. Such environmental laws regulate air emissions; protect water bodies; regulate the handling and disposal of hazardous substances and waste materials; establish siting and land use requirements; and protect against ecological impacts. Complex and lengthy processes are required to obtain and renew approvals, permits, and licenses for new, existing, or modified energy-related facilities. Additionally, the use and handling of various chemicals and hazardous materials require release prevention plans and emergency response procedures.Environmental regulations impact the electric utility industry, and compliance obligations could be costly for Ameren Missouri, which operates coal-fired and natural gas-fired energy centers. Compliance obligations under the Clean Air Act stem from a variety of programs including the NSPS, the MATS, emission allowance programs, the CSAPR, and the National Ambient Air Quality Standards, which are subject to periodic review for certain pollutants. Collectively, these regulations cover a variety of pollutants, such as SO2, particulate matter, NOx, mercury, toxic metals and acid gases, and CO2 emissions, although the scope of covered pollutants can change. To the extent our operations impact surface water bodies, including wetlands, the Clean Water Act requires permitting as well as evaluation of the ecological and biological impact of those operations.

SHORT-TERM DEBT AND LIQUIDITYThe liquidity needs of the Ameren Companies are supported through the use of available cash, drawings under committed credit agreements, commercial paper issuances, and/or, in the case of Ameren Missouri and Ameren Illinois, short-term affiliate borrowings.Short-Term BorrowingsIn December 2025, the Credit Agreements, which were scheduled to mature in December 2028, were extended and amended. The Credit Agreements now mature in December 2030. The Credit Agreements provide $3.2 billion of credit cumulatively through maturity. The total facility size of the Missouri Credit Agreement and Illinois Credit Agreement is $1.9 billion and $1.3 billion, respectively. The maturity date of each Credit Agreement may be extended for an additional one-year period upon the mutual consent of the respective borrowers and the lenders. Credit available under the agreements is provided by 20 international, national, and regional lenders, with no single lender providing more than $208 million of lending capacity across both agreements in the aggregate.The obligations of each borrower under the respective Credit Agreements to which it is a party are several and not joint. Except under limited circumstances relating to expenses and indemnities, the obligations of Ameren Missouri and Ameren Illinois under the respective Credit Agreements are not guaranteed by Ameren (parent) or any other subsidiary of Ameren. The following table presents the maximum aggregate amount available to each borrower under each facility:MissouriCredit AgreementIllinoisCredit AgreementAmeren (parent)$1,600 $800 Ameren Missouri1,600 (a)Ameren Illinois(a)1,100 (a)Not applicable.The borrowers have the option to seek additional commitments from existing or new lenders to increase the total facility size of the Credit Agreements to a maximum of $2.4 billion for the Missouri Credit Agreement and $1.6 billion for the Illinois Credit Agreement. Ameren (parent) borrowings are due and payable no later than the maturity date of the Credit Agreements. Ameren Missouri and Ameren Illinois borrowings under the applicable Credit Agreement are due and payable no later than the earlier of the maturity date or 364 days after the date of the borrowing.The obligations of the borrowers under the Credit Agreements are unsecured. Loans are available on a revolving basis under each of the Credit Agreements.

LONG-TERM DEBT AND EQUITY FINANCINGSThe following table presents long-term debt outstanding, including maturities due within one year, as of December 31, 2025 and 2024:20252024Ameren (Parent):3.65% Senior unsecured notes due 2026350 350 5.70% Senior unsecured notes due 2026600 600 1.95% Senior unsecured notes due 2027500 500 1.75% Senior unsecured notes due 2028450 450 5.00% Senior unsecured notes due 2029700 700 3.50% Senior unsecured notes due 2031800 800 5.375% Senior unsecured debt due 2035750 — Total long-term debt, gross4,150 3,400 Less: Unamortized discount and premium(3)(3)Less: Unamortized debt issuance costs(16)(14)Less: Maturities due within one year(950)— Long-term debt, net$3,181 $3,383 Ameren Missouri:Bonds and notes:2.95% Senior secured notes due 2027(a)$400 $400 3.50% First mortgage bonds due 2029(b)450 450 2.95% First mortgage bonds due 2030(b)465 465 2.15% First mortgage bonds due 2032(b)525 525 2.90% 1998 Series A bonds due 2033(c)60 60 2.90% 1998 Series B bonds due 2033(c)50 50 2.75% 1998 Series C bonds due 2033(c)50 50 5.20% First mortgage bonds due 2034(b)500 500 5.50% Senior secured notes due 2034(a)184 184 5.25% First mortgage bonds due 2035(b)500 — 5.30% Senior secured notes due 2037(a)300 300 8.45% Senior secured notes due 2039(a)(d)350 350 4.85% Securitized utility tariff bonds due 2039(e)459 476 3.90% Senior secured notes due 2042(a)(d)485 485 3.65% Senior secured notes due 2045(a)400 400 4.00% First mortgage bonds due 2048(b)425 425 3.25% First mortgage bonds due 2049(b)330 330 2.625% First mortgage bonds due 2051(b)550 550 3.90% First mortgage bonds due 2052(b)525 525 5.45% First mortgage bonds due 2053(b)500 500 5.25% First mortgage bonds due 2054(b)350 350 5.125% First mortgage bonds due 2055(b)450 450 Total long-term debt, gross8,308 7,825 Less: Long-term debt – related parties, gross(88)(58)Less: Unamortized discount and premium(15)(17)Less: Unamortized debt issuance costs(62)(62)Less: Maturities due within one year(23)(17)Long-term debt, net$8,120 $7,671 20252024Ameren Illinois:Bonds and notes:3.25% Senior secured notes due 2025(f)— 300 6.125% Senior secured notes due 2028(f)60 60 3.80% First mortgage bonds due 2028(g)430 430 1.55% First mortgage bonds due 2030(g)375 375 3.85% First mortgage bonds due 2032(g)500 500 4.95% First mortgage bonds due 2033(g)500 500 6.70% Senior secured notes due 2036(f)61 61 6.70% Senior secured notes due 2036(f)42 42 4.80% Senior secured notes due 2043(f)280 280 4.

INCOME TAXESIRAThe IRA was enacted in August 2022, and includes various income tax provisions, among other things. The law extends federal production and investment tax credits for projects beginning construction through 2024 and allows for a 10% adder to the production and investment tax credits for siting projects at existing energy communities as defined in the law, which includes sites previously used for coal-fired generation. The law also creates production and investment tax credits for projects beginning construction after 2024. The production and investment tax credits will apply to renewable energy production and investments, along with certain nuclear energy production. See the OBBBA below for additional information on revisions to the production and investment tax credits. The law allows for transferability, subject to revisions made by the OBBBA discussed below, to an unrelated party for cash of up to 100% of certain tax credits generated after 2022. In addition, the law imposes a 15% minimum tax on adjusted financial statement income, as defined in the law, for corporations whose average annual adjusted financial statement income exceeds $1 billion for three consecutive preceding tax years. Once a corporation exceeds this three-year average annual adjusted financial statement income threshold, it will be subject to the minimum tax for all future tax years. Additional regulations, interpretations, amendments, or technical corrections to or in connection with the IRA have been and are expected to be issued by the IRS or United States Department of Treasury, which may impact the timing of when the 15% minimum tax becomes applicable for Ameren.OBBBAThe OBBBA was enacted in July 2025 and includes various income tax provisions, among other things. The OBBBA modified provisions of the IRA related to production and investment tax credits. The new law maintains production and investment tax credits for solar and wind projects that begin construction within one year of the OBBBA’s enactment and are placed in-service by the end of 2030. Projects that begin construction after one year from enactment of the OBBBA but are placed in service by the end of 2027 also remain eligible. The law provides investment tax credits for battery storage projects that begin construction by the end of 2033, which phase out by the end of 2035.

STOCK-BASED COMPENSATIONThe 2022 Omnibus Incentive Compensation Plan is Ameren’s long-term incentive plan available for eligible employees and directors. It provides for a maximum of 8.8 million common shares to be available for grant to eligible employees and directors. At December 31, 2025, there were 7.3 million common shares remaining for grant. Awards may be restricted stock, restricted stock units, stock options (incentive stock options and nonqualified stock options), stock appreciation rights, performance awards, cash-based awards and other stock-based awards. Ameren used newly issued shares to fulfill its stock-based compensation obligations for 2025, 2024, and 2023, and intends to use newly issued shares to fulfill its stock-based compensation obligations for 2026.The following table summarizes Ameren’s outstanding performance share unit and restricted stock unit activity for the year ended December 31, 2025:Performance Share Units –Market Condition(a)Performance Share Units – Performance Condition(b)Restricted Stock UnitsShareUnitsWeighted-average Fair Value per Share UnitShareUnitsWeighted-average Fair Value per Share UnitStockUnitsWeighted-average Fair Value per Stock UnitOutstanding at January 1, 2025(c)808,950 $77.73 120,997 $79.09 395,520 $79.73 Granted245,464 123.19 40,408 96.66 132,931 97.33 Forfeitures(80,469)87.56 (13,337)82.09 (47,305)83.77 Dividend equivalents(d)22,947 87.13 3,452 82.34 10,968 82.72 Vested and distributed(217,017)92.75 (34,980)87.85 (119,601)87.95 Outstanding at December 31, 2025(c)779,875 $87.12 116,540 $82.31 372,513 $82.95 (a)The exact number of shares issued pursuant to a share unit varies from 0% to 200% of the target award, depending on actual company performance relative to the specified market conditions. Compensation cost on nonforfeited awards is recognized regardless of whether Ameren achieves the specified market conditions.(b)The exact number of shares issued pursuant to a share unit varies from 0% to 200% of the target award, depending on actual company performance relative to the performance goals. Compensation cost is recognized ratably over the requisite service period only for awards for which it is probable that the performance condition will be satisfied.(c)Outstanding awards include awards that vest on a pro-rata basis due to attainment of retirement eligibility by employees, but have not yet been distributed.

The Ameren Companies have identified cybersecurity as an enterprise risk, which is managed through Ameren's integrated enterprise risk management program. The program is designed to continuously assess risk and evaluate the likelihood and probability of impact to determine the appropriate risk tolerance and risk management strategies that inform our cybersecurity policies, investments, practices, controls, and countermeasures. The program is a comprehensive, consistently applied management framework that is designed to ensure all forms of material risk and opportunity are identified, reported, and managed in an effective manner overseen by the risk management steering committee. The risk management steering committee, which is composed of executive management and senior-level Ameren officers, with Ameren board of directors’ oversight, oversees and governs Ameren's enterprise risk management processes, which include the identification, assessment, mitigation, and monitoring of risks including strategic, operational, and cybersecurity risks.Ameren's board of directors maintains a standing committee, the Cybersecurity and Digital Technology Committee, which is focused on the oversight of Ameren's cybersecurity and digital technology risks. The committee has primary responsibility for oversight of cybersecurity and digital technology risk management, including the programs, policies, procedures, processes, controls and safeguards for digital technology, information security, prevention and detection of cybersecurity incidents or data breaches, legislative and regulatory compliance, and cybersecurity and digital technology matters as they relate to crisis preparedness, incident response plans, and disaster recovery and business continuity capabilities. The committee receives regular updates from the Chief Information Security Officer, the Chief Digital and Information Officer, executive management, and other members of senior management who collectively maintain the responsibility for both the execution and ongoing management of Ameren’s cybersecurity program and respective initiatives. The Cybersecurity and Digital Technology Committee regularly reports on its activities to Ameren’s board of directors, including reviewing and advising Ameren’s board of directors of any developments it believes should be considered.

OTHER INCOME, NETThe following table presents the components of “Other Income, Net” in the Ameren Companies’ statements of income for the years ended December 31, 2025, 2024, and 2023:202520242023Ameren:Other Income, NetAllowance for equity funds used during construction$88 $76 $54 Other interest income41 41 33 Non-service cost components of net periodic benefit income(a)247 304 295 Miscellaneous income17 9 7 Gain on extinguishment of debt(b)8 16 — Earnings (losses) related to equity method investments(19)(4)1 Donations(12)(5)(24)Miscellaneous expense(23)(20)(18)Total Other Income, Net$347 $417 $348 Ameren Missouri:Other Income, NetAllowance for equity funds used during construction$56 $58 $30 Other interest income9 8 11 Non-service cost components of net periodic benefit income(a)126 139 97 Miscellaneous income6 4 3 Donations(7)(2)(2)Miscellaneous expense(10)(11)(9)Total Other Income, Net$180 $196 $130 Ameren Illinois:Other Income, NetAllowance for equity funds used during construction$30 $17 $19 Other Interest income32 32 21 Non-service cost components of net periodic benefit income81 105 124 Miscellaneous income9 4 4 Donations(5)(3)(4)Miscellaneous expense(11)(8)(8)Total Other Income, Net$136 $147 $156 (a)For the years ended December 31, 2025, 2024, and 2023, the non-service cost components of net periodic benefit income were adjusted by amounts deferred of $(53) million, $(41) million, and $27 million, respectively, due to a regulatory tracking mechanism for the difference between the level of such costs incurred by Ameren Missouri under GAAP and the level of such costs included in rates. See Note 10 – Retirement Benefits for additional information.(b)See Note 5 – Long-term Debt and Equity Financings for additional information on Ameren (parent)’s repurchase of Ameren Missouri’s senior secured notes and first mortgage bonds and Ameren Illinois’ first mortgage bonds that were accounted for as a debt extinguishment.