Ameren 10-Q 2025-09-30

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 10-Q

OR

(Missouri Corporation)

1901 Chouteau Avenue

St. Louis, Missouri 63103

(314) 621-3222

(Missouri Corporation)

1901 Chouteau Avenue

St. Louis, Missouri 63103

(314) 621-3222

(Illinois Corporation)

10 Richard Mark Way

Collinsville, Illinois 62234

(618) 343-8150

Securities Registered Pursuant to Section 12(b) of the Act:

Indicate by check mark whether each registrant: (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days.

Indicate by check mark whether each registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T (§ 232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit such files).

Indicate by check mark whether each registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act.

Indicate by check mark whether each registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act).

The number of shares outstanding of each registrant’s classes of common stock as of October 31, 2025, was as follows:

This combined Form 10-Q is separately filed by Ameren Corporation, Union Electric Company, and Ameren Illinois Company. Each registrant hereto is filing on its own behalf all of the information contained in this quarterly report that relates to such registrant. Each registrant hereto is not filing any information that does not relate to such registrant, and therefore makes no representation as to any such information.

TABLE OF CONTENTS

GLOSSARY OF TERMS AND ABBREVIATIONS

We use the words “our,” “we” or “us” with respect to certain information that relates to Ameren, Ameren Missouri, and Ameren Illinois, collectively. When appropriate, subsidiaries of Ameren Corporation are named specifically as their various business activities are discussed. Refer to the Form 10-K for a complete listing of glossary terms and abbreviations. Only new or significantly changed terms and abbreviations are included below.

2023 PRP – Preferred Resource Plan, Ameren Missouri’s preferred plan for meeting customers’ projected long-term energy needs, which was filed with the MoPSC in September 2023 as a part of its integrated resource plan.

2025 Change to the 2023 PRP – A change to Ameren Missouri’s 2023 PRP filed with the MoPSC in February 2025 reflecting certain modifications to Ameren Missouri’s preferred plan for meeting customers’ projected long-term energy needs.

Form 10-K – The combined Annual Report on Form 10-K for the year ended December 31, 2024, filed by the Ameren Companies with the SEC.

OBBBA – The One Big Beautiful Bill Act, federal legislation enacted in July 2025.

QTD – Three months ended September 30.

YTD – Nine months ended September 30.

YoY – Compared with the year-ago period.

FORWARD-LOOKING STATEMENTS

Statements in this report not based on historical facts are considered “forward-looking” and, accordingly, involve risks and uncertainties that could cause actual results to differ materially from those discussed. Although such forward-looking statements have been made in good faith and are based on reasonable assumptions, there is no assurance that the expected results will be achieved. These statements include (without limitation) statements as to future expectations, beliefs, plans, projections, strategies, targets, estimates, objectives, events, conditions, and financial performance. In connection with the “safe harbor” provisions of the Private Securities Litigation Reform Act of 1995, we are providing this cautionary statement to identify important factors that could cause actual results to differ materially from those anticipated. The following factors, in addition to those discussed within Risk Factors in the Form 10-K, and elsewhere in this report and in our other filings with the SEC, could cause actual results to differ materially from management expectations suggested in such forward-looking statements:

• regulatory, judicial, or legislative actions, and any changes in regulatory policies and ratemaking determinations that may change regulatory recovery mechanisms, such as those that may result from Ameren Missouri’s request with the MoPSC to modify its existing large primary service tariff, Ameren Illinois’ appeal of the December 2023 and 2024 ICC orders for the MYRP electric distribution service regulatory rate review and June 2024 rehearing order to the Illinois Appellate Court for the Fifth Judicial District, Ameren Illinois’ electric distribution service revenue requirement reconciliation adjustment request filed with the ICC in April 2025, Ameren Illinois’ natural gas delivery service regulatory rate review filed with the ICC in January 2025, and the January and April 2025 appeals of FERC’s October 2024 and March 2025 orders by the MISO transmission owners, including Ameren Missouri, Ameren Illinois, and ATXI;

• our ability to control costs and make substantial investments in our businesses, including our ability to recover costs and investments, and to earn our allowed ROEs, within frameworks established by our regulators, while maintaining affordability of services for our customers;

• the effect and duration of Ameren Illinois’ election to utilize MYRPs for electric distribution service ratemaking effective for rates beginning in 2024, including the effect of the reconciliation cap on the electric distribution revenue requirement;

• the effect of Ameren Illinois’ use of the performance-based formula ratemaking framework for its participation in electric energy-efficiency programs, and the related impact of the direct relationship between Ameren Illinois’ ROE and the 30-year United States Treasury bond yields;

• the effect on Ameren Missouri of any customer rate caps or limitations on increasing the electric service revenue requirement pursuant to Ameren Missouri’s election to use the PISA;

• Ameren Missouri’s ability to construct and/or acquire wind, solar, and other renewable energy generation facilities and battery storage, as well as natural gas-fired and nuclear energy centers, extend the operating license for the Callaway Energy Center, retire fossil fuel-fired energy centers, and implement new or existing customer energy-efficiency programs, including any such construction, acquisition, retirement, or implementation in connection with its Smart Energy Plan, preferred resource plan, or emissions reduction goals, and to recover its cost of investment, a related return, and, in the case of customer energy-efficiency programs, any lost electric revenues in a timely manner, each of which is affected by the ability to obtain all necessary regulatory and project approvals, including CCNs from the MoPSC or any other required approvals;

• Ameren Missouri’s ability to earn, utilize, or transfer at a reasonable price federal production and investment tax credits related to renewable energy projects and nuclear energy production; the cost of wind, solar, and other renewable generation and battery storage technologies; and our ability to obtain timely interconnection agreements with the MISO or other RTOs at an acceptable cost for each facility;

• the outcome of the MISO long-range transmission planning process, including changes to planned projects, the ability to secure competitively bid or assigned projects and related approvals, including CCNs from the MoPSC and ICC or any other required approvals, and changes in applicable legislative or regulatory frameworks;

• the inability of our counterparties to meet their obligations with respect to contracts, credit agreements, and financial instruments, including as they relate to the construction and acquisition of electric and natural gas utility infrastructure and the ability of counterparties to complete projects, which is dependent upon the availability of necessary materials and equipment, including those obligations that are affected by supply chain disruptions;

• advancements in energy technologies, including carbon capture, utilization, and sequestration, hydrogen fuel for electric production and energy storage, next generation nuclear, and large-scale long-cycle battery energy storage, and the impact of federal and state energy and economic policies with respect to those technologies;

• the effects of changes in federal, state, or local laws and other domestic or international governmental actions, including monetary, fiscal, foreign trade, and energy policies, foreign trade tariffs, executive orders, or extended federal government shutdowns or defunding;

• the effects of changes in federal, state, or local tax laws or rates; additional regulations, interpretations, amendments, or technical corrections to, or in connection with the OBBBA and the IRA, including the effects of the OBBBA as it relates to construction timelines of solar and wind projects along with the ability to obtain materials for these projects to be eligible for federal production and investment tax credits, and the effects of the IRA as it relates to the 15% minimum tax on adjusted financial statement income; and any challenges to the tax positions taken by the Ameren Companies, as well as resulting effects on customer rates and the recoverability of the minimum tax imposed under the IRA;

• our ability to realize forecasted energy demand from potential new customers, including demand growth dependent on the addition of new data centers and other large primary service customers within our service territories;

• the effects on energy prices and demand for our services resulting from customer growth patterns or usage, including demand from data centers, technological advances, including advances in customer energy efficiency, electric vehicles, electrification of various industries, energy storage, and private generation sources, which generate electricity at the site of consumption and are becoming increasingly cost-competitive;

• the cost and availability of fuel, such as low-sulfur coal, natural gas, and enriched uranium used to produce electricity; the cost and availability of natural gas for distribution and the cost and availability of purchased power, including capacity, zero emission credits, renewable energy credits, and emission allowances; and the level and volatility of future market prices for such commodities and credits;

• disruptions in the delivery of fuel, failure of our fuel suppliers to provide adequate quantities or quality of fuel, or lack of adequate inventories of fuel, including nuclear fuel assemblies primarily from the one NRC-licensed supplier of assemblies for Ameren Missouri’s Callaway Energy Center;

• the cost and availability of transmission capacity required for the energy generated by Ameren Missouri’s energy centers or as required to satisfy our energy sales;

• the effectiveness of our risk management strategies and our use of financial and derivative instruments;

• the ability to obtain sufficient insurance, or, in the absence of insurance, the ability to timely recover uninsured losses from our customers;

*•*the impact of cyberattacks and data security risks on us, our suppliers, or other entities on the grid, which could, among other things, result in the loss of operational control of energy centers and electric and natural gas transmission and distribution systems and/or the loss of data, such as customer, employee, financial, and operating system information;

• acts of sabotage, which have increased in frequency and severity within the utility industry, war, terrorism, or other intentionally disruptive acts;

• business, economic, geopolitical, and capital market conditions, including foreign trade tariffs or trade wars, evolving federal regulatory priorities, and the impact of such conditions on interest rates, inflation, and investments;

*•*the impact of inflation or a recession on our customers and suppliers and the related impact on our results of operations, financial position, and liquidity;

• disruptions of the capital and credit markets, deterioration in credit metrics of the Ameren Companies, or other events that may have an adverse effect on the cost or availability of capital, including short-term credit and liquidity, and our ability to access the capital and credit markets on reasonable terms when needed;

• the actions of credit rating agencies and the effects of such actions;

• the impact of weather conditions and other natural conditions on us and our customers, including the impact of system outages and the level of wind and solar resources;

• the construction, installation, performance, and cost recovery of generation, transmission, and distribution assets;

• the ability to maintain system reliability during and after the transition to clean energy generation by Ameren Missouri and the electric utility industry, as well as Ameren Missouri’s ability to meet existing or future generation capacity obligations;

• the effects of failures of electric generation, electric and natural gas transmission or distribution, or natural gas storage facilities systems and equipment, which could result in unanticipated liabilities or unplanned outages;

• the operation of Ameren Missouri’s Callaway Energy Center, including planned and unplanned outages, as well as the ability to recover costs associated with such outages and the impact of such outages on off-system sales and purchased power, among other things;

• Ameren Missouri’s ability to recover the remaining investment and decommissioning costs associated with the retirement of an energy center, as well as the ability to earn a return on that remaining investment and those decommissioning costs;

• the impact of current environmental laws or their interpretation and new, more stringent, or changing requirements and environmental policies, including those related to NSR, CO2, NOx, SO2, and other emissions and discharges, Illinois emission standards, cooling water intake structures, CCR, energy efficiency, and wildlife protection, that could limit, terminate or otherwise modify the operation of certain of Ameren Missouri’s energy centers, increase our operating costs or investment requirements, result in an impairment of our assets, cause us to sell our assets, reduce our customers’ demand for electricity or natural gas, or otherwise have a negative financial effect;

• the impact of complying with renewable energy standards in Missouri and Illinois and with the zero emission standard in Illinois;

• the effectiveness of Ameren Missouri’s customer energy-efficiency programs and the related revenues and performance incentives earned under its MEEIA programs;

• Ameren Illinois’ ability to achieve the performance standards applicable to its electric distribution business and electric customer energy-efficiency goals and the resulting impact on its allowed ROE;

• labor disputes, workforce reductions, our ability to attract and retain professional and skilled-craft employees, changes in future wage and employee benefits costs, including those resulting from changes in discount rates, mortality tables, returns on benefit plan assets, and other assumptions;

• the impact of negative opinions of us or our utility services that our customers, investors, legislators, regulators, creditors, rating agencies, or other stakeholders may have or develop, which could result from a variety of factors, including failures in system reliability, failure to implement our investment plans or to protect sensitive customer information, increases in rates, negative media coverage, or concerns about company policies or practices;

• the impact of adopting new accounting and reporting guidance;

• the effects of strategic initiatives, including mergers, acquisitions, and divestitures;

• legal and administrative proceedings;

• pandemics or other significant global health events, and their impacts on our results of operations, financial position, and liquidity; and

• the impacts of the Russian invasion of Ukraine and conflicts in the Middle East, related sanctions imposed by the United States and other governments, and any broadening of these or other global conflicts, including potential impacts on the cost and availability of fuel, natural gas, enriched uranium, and other commodities, materials, and services.

New factors emerge from time to time, and it is not possible for management to predict all of such factors, nor can it assess the impact of each such factor on the business or the extent to which any factor, or combination of factors, may cause actual results to differ materially from those contained or implied in any forward-looking statement. Given these uncertainties, undue reliance should not be placed on these forward-looking statements. Except to the extent required by the federal securities laws, we undertake no obligation to update or revise publicly any forward-looking statements to reflect new information or future events.

PART I. FINANCIAL INFORMATION

AMEREN CORPORATION

CONSOLIDATED STATEMENT OF INCOME AND COMPREHENSIVE INCOME

(Unaudited) (In millions, except per share amounts)

The accompanying notes are an integral part of these consolidated financial statements.

AMEREN CORPORATION

CONSOLIDATED BALANCE SHEET

(Unaudited) (In millions, except per share amounts)

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The following discussion should be read in conjunction with the financial statements contained in this Form 10-Q, as well as Management’s Discussion and Analysis of Financial Condition and Results of Operations and Risk Factors contained in the Form 10-K. We intend for this discussion to provide the reader with information that will assist in understanding our financial statements, the changes in certain key items in those financial statements, and the primary factors that accounted for those changes, as well as how certain accounting principles affect our financial statements. The discussion also provides information about the financial results of our business segments to provide a better understanding of how those segments and their results affect the financial condition and results of operations of Ameren as a whole. Also see the Glossary of Terms and Abbreviations at the front of this report and in the Form 10-K.

Ameren, headquartered in St. Louis, Missouri, is a public utility holding company whose primary assets are its equity interests in its subsidiaries. Ameren’s subsidiaries are separate, independent legal entities with separate businesses, assets, and liabilities. Dividends on Ameren’s common stock and the payment of expenses by Ameren depend on distributions made to it by its subsidiaries. Ameren’s principal subsidiaries are listed below. Ameren also has other subsidiaries that conduct other activities, such as providing shared services.

• Ameren Missouri operates a rate-regulated electric generation, transmission, and distribution business and a rate-regulated natural gas distribution business in Missouri.

• Ameren Illinois operates rate-regulated electric transmission, electric distribution, and natural gas distribution businesses in Illinois.

• ATXI operates a FERC rate-regulated electric transmission business within the MISO.

Ameren’s and Ameren Missouri’s financial statements are prepared on a consolidated basis and therefore include the accounts of their majority-owned subsidiaries. All intercompany transactions have been eliminated. Ameren Illinois has no subsidiaries. All tabular dollar amounts are in millions, unless otherwise indicated.

In addition to presenting results of operations and earnings amounts in total, we present certain information in cents per share. These amounts reflect factors that directly affect Ameren’s earnings. We believe this per share information helps readers to understand the impact of these factors on Ameren’s earnings per diluted share.

OVERVIEW

Net income attributable to Ameren common shareholders in the three months ended September 30, 2025, was $640 million, or $2.35 per diluted share, compared with $456 million, or $1.70 per diluted share, in the year-ago period. Net income attributable to Ameren common shareholders in the nine months ended September 30, 2025, was $1,204 million, or $4.43 per diluted share, compared with $975 million, or $3.65 per diluted share, in the year-ago period. Net income was favorably affected for the three and nine months ended September 30, 2025, by increased base rate revenues at Ameren Missouri effective June 1, 2025, pursuant to the April 2025 MoPSC electric rate order and decreased tax expense at Ameren Transmission due to the revaluation of excess deferred income tax regulatory liabilities. Earnings were also favorably affected for the three and nine months ended September 30, 2025, by decreased other operations and maintenance expenses not subject to formula rates, riders, or trackers, largely because of the absence in 2025 of an Ameren Missouri charge related to the resolution of outstanding claims in the NSR and Clean Air Act litigation associated with the Rush Island Energy Center. Additionally, earnings were favorably affected for the three and nine months ended September 30, 2025, by increased retail electric sales volumes at Ameren Missouri, primarily due to warmer July temperatures and colder winter temperatures in 2025 and growth in retail electric sales and by the increased deferral of financing costs related to rate base investments at Ameren Missouri, and by increased infrastructure investments at Ameren Transmission and Ameren Illinois Electric Distribution. Net income was unfavorably affected for the three and nine months ended September 30, 2025, by increased financing costs, primarily resulting from higher interest rates on higher debt balances at Ameren (parent) and Ameren Missouri and by increased other operations and maintenance expenses not subject to formula rates, riders, or trackers, excluding a charge related to the NSR and Clean Air Act litigation, primarily due to higher storm costs, higher energy center maintenance expenses, and higher transmission and distribution vegetation management costs.

Ameren’s strategic plan includes investing in rate-regulated energy infrastructure, enhancing regulatory frameworks and advocating for responsible policies, and optimizing operating performance to capitalize on opportunities to benefit our customers, communities, shareholders, and the environment. Ameren remains focused on disciplined cost management and strategic capital allocation. Ameren invested $3.1 billion in its rate-regulated businesses in the nine months ended September 30, 2025.

In April 2025, Missouri Senate Bill 4 was enacted and became effective in August 2025. The law includes certain provisions that affect the regulation of Ameren Missouri’s electric and natural gas businesses. These provisions create modifications to the PISA and integrated resource planning, require electric utilities to submit service tariff schedules for high-demand customers, allow the MoPSC to authorize inclusion of construction work in progress in rate base for new natural gas-fired generation facilities and new generation facilities approved through integrated resource planning, and allow natural gas utilities to file regulatory rate reviews using a future test year, among other things.

In April 2025, the MoPSC issued an order in Ameren Missouri’s 2024 electric service regulatory rate review, approving nonunanimous stipulations and agreements. The order authorizes an increase of $355 million to Ameren Missouri’s annual revenue requirement for electric retail service, effective June 1, 2025. The approved revenue requirement was based on infrastructure investments as of December 31, 2024. The order did not explicitly specify an ROE, capital structure, rate base, or any rate base disallowances. The order provides for the continued use of all existing riders and trackers. The order also changed annualized depreciation, regulatory asset and liability amortization amounts, and the base level of expenses for trackers. On an annualized basis, these changes reflect an increase in “Depreciation and amortization” of approximately $70 million, among other expense changes, on Ameren’s and Ameren Missouri’s consolidated statements of income.

In November 2025, Ameren Missouri updated its May 2025 request with the MoPSC to modify its existing large primary service tariff to require customers requesting 75 MWs or more of demand and who are served at transmission level voltage to comply with additional tariff terms. The additional terms include a service term of 12 years plus a ramp period of up to five years to reach peak demand, minimum demand charges of 80% of contracted capacity, customer exit terms and fees, and customer credit and collateral requirements, among other terms. In addition, new customer programs would be available under this tariff, which allow customers to support renewable generation, battery storage, and/or nuclear generation through incremental payments. A decision by the MoPSC is expected by February 2026.

In June 2025, Ameren Missouri filed for a CCN with the MoPSC to construct the Big Hollow Natural Gas (800-MW facility) and the Big Hollow Battery Energy Storage (400-MW facility) projects. In August 2025, Ameren Missouri filed for a

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There have been no material changes to the quantitative and qualitative disclosures about interest rate risk, credit risk, commodity price risk, investment price risk, and commodity supplier risk included in the Form 10-K. See Item 7A under Part II of the Form 10-K for a more detailed discussion of our market risk.

(a)Evaluation of Disclosure Controls and Procedures

As of September 30, 2025, evaluations were performed under the supervision and with the participation of management, including the principal executive officer and the principal financial officer of each of the Ameren Companies, of the effectiveness of the design and operation of such registrant’s disclosure controls and procedures (as defined in Rules 13a-15(e) and 15d-15(e) of the Exchange Act). Based on those evaluations, as of September 30, 2025, the principal executive officer and the principal financial officer of each of the Ameren Companies concluded that such disclosure controls and procedures are effective to provide assurance that information required to be disclosed in such registrant’s reports filed or submitted under the Exchange Act is recorded, processed, summarized, and reported within the time periods specified in the SEC’s rules and forms and such information is accumulated and communicated to its management, including its principal executive officer and its principal financial officer, to allow timely decisions regarding required disclosure.

(b)Changes in Internal Controls over Financial Reporting

There has been no change in any of the Ameren Companies’ internal control over financial reporting during their most recent fiscal quarter that has materially affected, or is reasonably likely to materially affect, each of their internal control over financial reporting.

PART II. OTHER INFORMATION

ITEM 1. LEGAL PROCEEDINGS.

We are involved in legal and administrative proceedings before various courts and 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 this report, will not have a material adverse effect on our results of operations, financial position, or liquidity. Risk of loss is mitigated, in some cases, by insurance or contractual or statutory indemnification. We believe that we have established appropriate reserves for potential losses. For additional information on material legal and administrative proceedings, see Note 2 – Rate and Regulatory Matters, Note 9 – Commitments and Contingencies, and Note 10 – Callaway Energy Center, under Part I, Item 1, of this report.

Pursuant to Item 103(c)(3)(iii) of Regulation S-K, our policy is to disclose environmental proceedings to which a governmental entity is a party if we reasonably believe such proceedings will result in monetary sanctions of $1 million or more.

For a detailed discussion of our risk factors, see the information disclosed in Part I, Item 1A, of the Form 10-K.

ITEM 2. UNREGISTERED SALES OF EQUITY SECURITIES AND USE OF PROCEEDS.

Ameren Corporation, Ameren Missouri, and Ameren Illinois did not purchase equity securities reportable under Item 703 of Regulation S-K during the period from July 1, 2025, to September 30, 2025.

Insider Adoption or Termination of Trading Arrangements

During the fiscal quarter ended September 30, 2025, none of our directors or officers informed us of the adoption or termination of a “Rule 10b5-1 trading arrangement” or “non-Rule 10b5-1 trading arrangement,” as those terms are defined in Regulation S-K, Item 408, except as follows:

On August 13, 2025, Theresa A. Shaw, Senior Vice President, Finance and Chief Accounting Officer of Ameren, adopted a Rule 10b5-1 trading arrangement that provides for the sale of an aggregate of up to 1,300 shares to be sold in four equal quarterly installments between November 2025 and November 2026, subject to certain price limitations set forth in the trading arrangement. Ms. Shaw’s 10b5-1 trading arrangement will terminate on the earlier of: (i) November 13, 2026; (ii) execution of all trades or expiration of all orders relating to such trades under the Rule 10b5-1 trading arrangement; or (iii) such date as the Rule 10b5-1 trading arrangement is otherwise terminated according to its terms.

The trading arrangement discussed above is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c).

The documents listed below are being filed or have previously been filed on behalf of the Ameren Companies and are incorporated herein by reference from the documents indicated and made a part hereof. Exhibits not identified as previously filed are filed herewith.

The file number references for the Ameren Companies’ filings with the SEC are: Ameren, 1-14756; Ameren Missouri, 1-2967; and Ameren Illinois, 1-3672.

Each registrant hereby undertakes to furnish to the SEC upon request a copy of any long-term debt instrument not listed above that such registrant has not filed as an exhibit pursuant to the exemption provided by Item 601(b)(4)(iii)(A) of Regulation S-K.

SIGNATURES

Pursuant to the requirements of the Exchange Act, each registrant has duly caused this report to be signed on its behalf by the undersigned thereunto duly authorized. The signature for each undersigned company shall be deemed to relate only to matters having reference to such company or its subsidiaries.

Date: November 6, 2025