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ITEM 7.MANAGEMENT’S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS

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.

Below is a summary description of Ameren’s principal subsidiaries – Ameren Missouri, Ameren Illinois, and ATXI. Ameren also has other subsidiaries that conduct other activities, such as providing shared services. A more detailed description can be found in Note 1 – Summary of Significant Accounting Policies under Part II, Item 8, of this report.

•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 in the MISO.

Ameren 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. See Note 16 – Segment Information under Part II, Item 8, of this report for further discussion of Ameren’s and Ameren Illinois’ segments.

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 Missouri’s subsidiaries were created for the ownership of renewable generation projects. Ameren Illinois has no subsidiaries. All tabular dollar amounts are in millions, unless otherwise indicated.

The following discussion should be read in conjunction with the financial statements contained in this 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. Discussion regarding our financial condition and results of operations for the year ended December 31, 2021, including comparisons with the year ended December 31, 2022, is included in Item 7 of our Form 10-K for the year ended December 31, 2022.

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.

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OVERVIEW

Our core strategy is driven by the following three pillars, which allow us to capitalize on opportunities to benefit our customers, communities, shareholders, and the environment:

Rate Base ($ in billions)(a) Regulatory Frameworks(c) Improved Reliability(f)

Segment Regulatory Framework

AmerenTransmission Formula ratemakingAllowed ROE of 10.52%

Key announcements, updates, and regulatory outcomes

In June 2023, the MoPSC issued an order that resulted in an increase of $140 million to Ameren Missouri’s annual revenue requirement for electric retail service. The approved revenue requirement was based on infrastructure investments as of December 31, 2022, and included an extension of the depreciable lives of the Sioux Energy Center’s assets from 2028 to 2030. The order did not explicitly specify an ROE, capital structure, or rate base. The order provides for the continued use of the FAC and trackers for pension and postretirement benefits, uncertain income tax positions, certain excess deferred income taxes, and renewable energy standard compliance costs that the MoPSC previously authorized in earlier electric rate orders, as well as the use of an electric property tax tracker. It also includes a tracker for the utilization of production and investment tax credits or proceeds from the sale of such tax credits allowed under the IRA. The order increased the annualized base level of net energy costs pursuant to the FAC by approximately $40 million from the base level established in the MoPSC’s December 2021 electric rate order. 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 approximate increases in “Depreciation and amortization” of $90 million and “Other income, net”, of $100 million, related to non-service pension and postretirement benefit income, on Ameren’s and Ameren Missouri’s consolidated statements of income. The new rates became effective on July 9, 2023.

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In June 2023, Ameren Missouri filed for CCNs with the MoPSC for four solar generation facilities, including the Split Rail Solar Project (300-MW facility, build-transfer agreement), the Cass County Solar Project (150-MW facility, development-transfer agreement), the Vandalia Solar Project (50-MW facility, self-build), and the Bowling Green Solar Project (50-MW facility, self-build). In February 2024, Ameren Missouri, the MoPSC staff, and the MoOPC filed a nonunanimous stipulation and agreement requesting the MoPSC approve Ameren Missouri’s requests for CCNs for the Split Rail, Vandalia, and Bowling Green solar projects. The stipulation and agreement also requests MoPSC approval of the CCN request for the Cass County Solar Project conditioned upon the facility supporting the Renewable Solutions Program and full subscription of the portion of the program supported by this facility, subject to certain other terms and conditions. The remaining intervenors did not object to the agreement. Ameren Missouri expects a decision by the MoPSC in March 2024. Each project is expected to support Ameren Missouri’s transition to renewable generation and, in addition, the Cass County Solar Project is expected to support Ameren Missouri’s Renewable Solutions Program. In February and April 2023, the MoPSC issued orders approving requested CCNs for the Huck Finn and Boomtown solar projects, respectively.

In August 2023, the MoPSC issued an order approving a nonunanimous stipulation and agreement to extend Ameren Missouri’s MEEIA 2019 program for an additional year through 2024. For 2024, the order approved the establishment of a portfolio of customer energy-efficiency programs and performance incentives that will provide Ameren Missouri an opportunity to earn revenues, including $12 million of performance incentive revenues if Ameren Missouri achieves certain program spending goals. In 2024, Ameren Missouri expects to invest $76 million in energy-efficiency programs. In January 2024, Ameren Missouri filed a proposed customer energy-efficiency plan with the MoPSC under the MEEIA for 2025 through 2027. The proposed plan includes a portfolio of customer energy-efficiency programs, along with the continued use of the MEEIA rider, which allows Ameren Missouri to collect from, or refund to, customers any difference in actual MEEIA program costs and related lost electric margins and the amounts collected from customers. If the plan is approved, Ameren Missouri intends to invest $123 million annually in the proposed customer energy-efficiency programs from 2025 to 2027. In addition, Ameren Missouri requested performance incentives applicable to each plan year to earn revenues by achieving certain customer energy-efficiency savings and target spending goals. If 100% of the goals are achieved, Ameren Missouri would earn performance incentive revenues totaling $56 million over the three-year plan. Ameren Missouri also requested additional performance incentives applicable to each plan year totaling up to $14 million over the three-year plan, if Ameren Missouri exceeds 100% of the goals. Ameren Missouri expects a decision by the MoPSC by October 2024 but cannot predict the ultimate outcome of this regulatory proceeding.

In November 2023, Ameren Missouri petitioned the MoPSC for a financing order to authorize the issuance of securitized utility tariff bonds to finance $519 million of costs related to the planned accelerated retirement of the Rush Island Energy Center, which includes the expected remaining unrecovered net plant balance associated with the facility. Ameren Missouri requested to collect the amounts necessary to repay the bonds over approximately 15 years from the date of bond issuance. In February 2024, the MoPSC staff filed a response to Ameren Missouri’s petition that stated Ameren Missouri’s decision to accelerate the retirement of the Rush Island Energy Center was prudent and largely supported Ameren Missouri’s securitization request. However, the MoPSC staff claimed Ameren Missouri’s prior actions that resulted in the adverse ruling in the NSR and Clean Air Act Litigation discussed in Note 14 – Commitments and Contingencies under Part II, Item 8, of this report, were imprudent and recommended that the impact of those actions on customers be considered in future rate reviews. If Ameren Missouri is not allowed to recover Rush Island Energy Center costs through securitization or if future rate reviews result in revenue reductions based on Ameren Missouri’s prior actions that resulted in the adverse ruling in the NSR and Clean Air Act Litigation, it could have a material adverse effect on the results of operations, financial position, and liquidity of Ameren and Ameren Missouri. Ameren Missouri expects a decision by the MoPSC by the end of June 2024, but cannot predict the ultimate outcome of this regulatory proceeding.

In February 2024, Ameren Missouri filed an update to its Smart Energy Plan with the MoPSC, which includes a five-year capital investment overview with a detailed one-year plan for 2024. The plan is designed to upgrade Ameren Missouri’s electric infrastructure and includes investments that will upgrade the grid and accommodate more renewable energy. Investments under the plan are expected to total approximately $12.4 billion over the five-year period from 2024 through 2028, with expenditures largely recoverable under the PISA. Ameren Missouri’s Smart Energy Plan excludes investments in its natural gas distribution business, as well as removal costs, net of salvage.

In December 2023, the ICC issued an order in Ameren Illinois' MYRP proceeding, approving base rates for electric distribution services for 2024 through 2027 and rejecting Ameren Illinois' Grid Plan, which was addressed as part of the MYRP proceeding. Rate changes consistent with the order became effective in January 2024. The ICC concluded that the proposed Grid Plan did not meet certain statutory requirements and directed Ameren Illinois to file a revised Grid Plan within three months. Ameren Illinois expects to file a revised Grid Plan with the ICC in March 2024, and also expects to file a request to update the associated MYRP revenue requirements for 2024 through 2027 in the first half of 2024. The December 2023 order adopted an alternative methodology to establish a rate base and revenue requirements for the years 2024 through 2027, using the 2022 year-end rate base approved by the ICC in its 2022 electric distribution service revenue requirement reconciliation adjustment order discussed below. This rate base will remain in effect through 2027, unless subsequently changed by the ICC in the rehearing discussed below or if approval of a revised Grid Plan results in an update of each year’s revenue requirement.

In January 2024, Ameren Illinois filed a request for rehearing of the ICC's December 2023 order. The filing contended that the use of the 2022 year-end rate base for each year of the MYRP, until a revised Grid Plan is approved, is unlawful and not in compliance with the CEJA. In addition, the filing requested the ICC revise the order to include an allowed ROE of at least 9.82% for each year of the MYRP and include

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a base level of investments to maintain grid reliability in each year of the MYRP, among other things. In January 2024, the ICC partially denied Ameren Illinois’ rehearing request by denying Ameren Illinois’ request regarding the allowed ROE, and granting Ameren Illinois’ request to consider whether it is appropriate to use the 2022 year-end rate base for each year of the MYRP and to include a base level of investments to maintain grid reliability in each year of the MYRP. Additionally, the scope of the rehearing will include a review of certain operations and maintenance expenses in each year of the MYRP. In February 2024, Ameren Illinois filed its request in the rehearing proceeding, which proposed updated revenue requirements and annual rate base amounts to reflect a base level of investments to maintain grid reliability for 2024 through 2027. An ICC decision in this rehearing is expected by late June 2024. Also, in January 2024, Ameren Illinois filed an appeal of the December 2023 ICC order and the partial denial of Ameren Illinois’ request for rehearing to the Illinois Appellate Court for the Fifth Judicial District. The court is under no deadline to address the appeal. Ameren Illinois cannot predict the ultimate outcome of the revised Grid Plan filing, its request to update the associated MYRP revenue requirements for 2024 through 2027, the rehearing proceeding, or the appeal to the Illinois Appellate Court for the Fifth Judicial District.

The following table presents the approved revenue requirements, ROE, capital structure common equity percentage, and annual rate base in the ICC’s December 2023 order, as well as the proposed revenue requirements and annual rate base amounts in Ameren Illinois’ February 2024 rehearing request filing:

ICC’s December 2023 MYRP Order:

Ameren Illinois’ February 2024 Rehearing Request Filing:

(a)The ROE is under appeal as discussed above.

The approved revenue requirements in the ICC’s December 2023 order represent a cumulative increase of $142 million compared to a cumulative increase of $444 million requested by Ameren Illinois in its revised September 2023 MYRP filing. The ICC’s December 2023 order did not utilize a phase-in provision that is permitted by the CEJA for any initial rate increase.

In November 2023, the ICC issued an order approving Ameren Illinois’ 2022 electric distribution service revenue requirement reconciliation adjustment filing. This order approved a reconciliation adjustment of $110 million, which reflected Ameren Illinois’ actual 2022 recoverable costs, year-end rate base of $3.9 billion, and a capital structure composed of 50% common equity. The approved reconciliation adjustment will be collected from customers in 2024. In addition, Ameren Illinois will file its 2023 electric distribution service revenue requirement reconciliation with the ICC by May 2024, which will reflect its 2023 year-end rate base. The 2023 reconciliation adjustment, if approved by the ICC, will be collected from customers in 2025.

In November 2023, the ICC issued an order in Ameren Illinois’ January 2023 natural gas delivery service regulatory rate review, which resulted in an increase to its annual revenues for natural gas delivery service of $112 million based on a 9.44% allowed ROE, a capital structure composed of 50% common equity, and a rate base of approximately $2.85 billion. The order reflected a reduction of approximately $93 million of planned distribution and transmission capital investments included in Ameren Illinois’ requested revenue increase, which used a 2024 future test year. The new rates became effective on November 28, 2023. In December 2023, Ameren Illinois filed a request for rehearing of the ICC's November 2023 order. The filing requested the ICC revise the order to include an allowed ROE of at least 9.89%, a capital structure composed of 52% common equity, and a reversal of the approximately $93 million reduction of planned distribution and transmission capital investments included in the order, among other things. In January 2024, the ICC denied Ameren Illinois’ rehearing request. Subsequently, in January 2024, Ameren Illinois filed an appeal of the November 2023 ICC order and the January 2024 ICC denial of Ameren Illinois’ request for rehearing to the Illinois Appellate Court for the Fifth Judicial District. The court is under no deadline to address the appeal. Ameren Illinois cannot predict the ultimate outcome of this appeal.

In November 2023, the ICC issued an order in Ameren Illinois’ annual update filing that approved electric customer energy-efficiency rates of $100 million beginning in January 2024, which represents an increase of $24 million from 2023 rates. The order was based on a projected 2024 year-end rate base of $394 million.

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In 2021, the MISO issued a report outlining a preliminary long-range transmission planning roadmap of projects through 2039, which considers the rapidly changing generation mix within MISO resulting from significant additions of renewable generation, actual and expected generation plant closures, and state mandates or goals for clean energy or carbon emissions reductions. In July 2022, the MISO approved the first tranche of projects under the first phase of the roadmap. A portion of these projects were assigned to various utilities, of which Ameren was awarded projects that are estimated to cost approximately $1.8 billion, based on the MISO’s cost estimate. Related to these projects, Ameren expects to begin substation upgrades in 2024 in advance of transmission line construction, which is expected to begin in 2026, with forecasted completion dates near the end of this decade. In 2022 and 2023, the MISO initiated requests for proposals for first tranche competitive bid projects. In October and November 2023, first tranche competitive bid projects were awarded to ATXI and represent a total estimated investment of approximately $0.1 billion. The remaining competitive-bid project is estimated by the MISO to cost approximately $0.6 billion and is expected to be awarded by mid-2024. In February 2024, Ameren Illinois and ATXI filed a request for a CCN with the ICC related to the portion of the MISO long-range transmission projects discussed above that are expected to be constructed within the ICC’s jurisdiction. A decision by the ICC is expected by February 2025.

In February 2023, Ameren’s board of directors increased the quarterly common stock dividend to 63 cents per share, resulting in an annualized equivalent dividend rate of $2.52 per share. In February 2024, Ameren’s board of directors increased the quarterly common stock dividend to 67 cents per share, resulting in an annualized equivalent dividend rate of $2.68 per share.

For further information on the matters discussed above, see Note 2 – Rate and Regulatory Matters under Part II, Item 8, of this report, and the Outlook section below.

Earnings

Net income attributable to Ameren common shareholders was $1,152 million, or $4.38 per diluted share, for 2023, and $1,074 million, or $4.14 per diluted share, for 2022. Net income was favorably affected in 2023, compared with 2022, by increased infrastructure investments across all business segments and a higher recognized ROE at Ameren Illinois Electric Distribution as well as increased base rate revenues at Ameren Missouri pursuant to the June 2023 MoPSC electric rate order. Earnings were also favorably affected by decreased other operations and maintenance expenses not subject to formula rates, riders, or trackers, including an increase in the cash surrender value of COLI, at Ameren Missouri and Ameren Illinois Natural Gas. Net income was unfavorably affected in 2023, compared with 2022, by decreased retail sales at Ameren Missouri and Ameren Illinois Natural Gas, primarily due to milder winter and summer temperatures. In addition, lower retail sales volumes, excluding the estimated effects of weather, decreased net income at Ameren Missouri in 2023, compared with 2022. Earnings in 2023, compared to 2022, were also unfavorably affected by increased financing costs at Ameren (parent), Ameren Missouri, and Ameren Illinois Natural Gas, primarily due to higher interest rates on increased levels of short-term borrowings at Ameren (parent), and higher long-term debt balances and higher interest rates on short-term borrowings and long-term debt, partially offset by higher levels of allowance for funds used during construction, at Ameren Missouri and Ameren Illinois Natural Gas.

Liquidity

At December 31, 2023, Ameren, on a consolidated basis, had available liquidity in the form of cash on hand and amounts available under the Credit Agreements of $2.1 billion.

Ameren has an ATM program under which Ameren may offer and sell from time to time common stock, which includes the ability to enter into forward sale agreements, subject to market conditions and other factors. As of December 31, 2023, Ameren had approximately $770 million of common stock available for sale under the ATM program, which takes into account the forward sale agreements in effect as of December 31, 2023. For information regarding long-term debt issuances and maturities, common stock issuances, and outstanding forward sale agreements entered into under the ATM program through the date of this report, see Note 5 – Long-term Debt and Equity Financings under Part II, Item 8, of this report.

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Ameren remains focused on strategic capital allocation. The following chart presents 2023 capital expenditures by segment and the midpoint of projected cumulative capital expenditures for 2024 through 2028 by segment:

Ameren Missouri(a) Ameren Illinois Natural Gas

Ameren Illinois Electric Distribution Ameren Transmission

For 2024 through 2028, Ameren’s cumulative capital expenditures are projected to range from $21.0 billion to $22.8 billion. The following table presents the range of projected spending by segment:

Range (in billions)

Ameren Missouri(a) $ 12.5 – $ 13.5

Ameren Illinois Electric Distribution(b) 2.8 – 3.1

Ameren Illinois Natural Gas(b) 1.8 – 1.9

Ameren Transmission 3.9 – 4.3

(a)Amounts include $3.3 billion of renewable generation investments and $2.7 billion of dispatchable generation investments, which includes $0.9 billion related to coal-fired generation, through 2028, consistent with Ameren Missouri’s 2023 IRP.

(b)Amounts include investments necessary to meet compliance requirements of the CEJA, while continuing to ensure safe and adequate service is maintained. Ameren Illinois’ estimates may be revised as a result of future ICC orders related to its MYRP.

RESULTS OF OPERATIONS

Our results of operations and financial position are affected by many factors. Economic conditions, energy-efficiency investments by our customers and by us, technological advances, distributed generation, and the actions of key customers can significantly affect the demand for our services. Ameren and Ameren Missouri results are also affected by seasonal fluctuations in winter heating and summer cooling demands and by weather conditions, such as storms, as well as by energy center maintenance outages. Additionally, fluctuations in interest rates and conditions in the capital and credit markets affect our cost of borrowing, our pension and postretirement benefits costs, the cash surrender value of COLI, and the asset value of Ameren Missouri’s nuclear decommissioning trust fund. Almost all of Ameren’s revenues are subject to state or federal regulation. This regulation has a material impact on the rates we charge customers for our services. Our results of operations, financial position, and liquidity are affected by our ability to align our overall spending, both operating and capital, with the frameworks established by our regulators. See Note 2 – Rate and Regulatory Matters under Part II, Item 8, of this report for additional information regarding Ameren Missouri’s, Ameren Illinois’, and ATXI’s regulatory frameworks.

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We are observing inflationary pressures on the prices of labor, services, materials, and supplies, as well as high interest rates. Ameren Missouri and Ameren Illinois are generally allowed to pass on to customers prudently incurred costs for fuel, purchased power, and natural gas supply. Additionally, for certain non-commodity cost changes, the use of trackers, riders, formula ratemaking, and future test years, as applicable, mitigates our exposure.

Ameren Missouri principally uses coal and enriched uranium for fuel in its electric operations and purchases natural gas for its customers. Ameren Illinois purchases power and natural gas for its customers. The prices for these commodities can fluctuate significantly because of the global economic and political environment, weather, supply, demand, inflation, and many other factors. We have natural gas cost recovery mechanisms for our Illinois and Missouri natural gas distribution businesses, a purchased power cost recovery mechanism for Ameren Illinois’ electric distribution business, and a FAC for Ameren Missouri’s electric business.

We employ various risk management strategies to reduce our exposure to commodity risk and other risks inherent in our business. The reliability of Ameren Missouri’s energy centers and our transmission and distribution systems and the level and timing of operations and maintenance costs and capital investment are key factors that we seek to manage in order to optimize our results of operations, financial position, and liquidity.

Earnings Summary

The following table presents a summary of Ameren’s earnings for the years ended December 31, 2023 and 2022:

Net income attributable to Ameren common shareholders $ 1,152 $ 1,074

Earnings per common share – diluted 4.38 4.14

Net income attributable to Ameren common shareholders in 2023 increased $78 million, or $0.24 per diluted share, from 2022. The increase was due to net income increases of $56 million, $33 million, and $11 million at Ameren Illinois Electric Distribution, Ameren Transmission, and Ameren Illinois Natural Gas, respectively. The increases in net income were partially offset by a net income decrease of $17 million at Ameren Missouri and an increase in the net loss for activity not reported as part of a segment, primarily at Ameren (parent), of $5 million.

Earnings per share in 2023, compared with 2022, were favorably affected by:

•increased rate base investments at Ameren Transmission and Ameren Illinois Electric Distribution and a higher recognized ROE due to a higher annual average of the monthly yields of the 30-year United States Treasury bonds at Ameren Illinois Electric Distribution, which increased revenues at these segments (25 cents per share);

•increased base rate revenues at Ameren Missouri effective July 9, 2023, pursuant to the June 2023 MoPSC electric rate order, partially offset by the amortization of previously deferred depreciation expense under the PISA and RESRAM, financing costs otherwise recoverable under the PISA and RESRAM, a lower base level of expenses included in trackers, and the net recovery for amounts associated with the reduction in sales volumes resulting from MEEIA programs (12 cents per share);

•decreased other operations and maintenance expenses not subject to formula rates, riders, or trackers, including an increase in the cash surrender value of COLI, primarily at Ameren Missouri and Ameren Illinois Natural Gas (11 cents per share);

•decreased income tax expense not subject to formula rates or riders due, in part, to decreased income tax expense recognized at Ameren (parent) because of changes in the state income taxes apportioned to Missouri and Illinois, reflecting changes in revenues, as well as the effect of favorable market returns on COLI, compared with unfavorable returns in the year-ago period (6 cents per share);

•increased base rate revenues at Ameren Missouri for the inclusion of previously deferred PISA and RESRAM interest charges pursuant to the December 2021 and June 2023 MoPSC electric rate orders effective February 28, 2022, and July 9, 2023, respectively, partially offset by increased interest charges resulting from lower deferrals related to infrastructure investments associated with the PISA and RESRAM (6 cents per share);

•decreased taxes other than income taxes, primarily at Ameren Missouri, largely resulting from employee retention tax credits received under the Coronavirus Aid, Relief, and Economic Security Act in 2023 (3 cents per share);

•increased Ameren Illinois Natural Gas earnings from investments in qualifying infrastructure recovered under the QIP (3 cents per share);

•increased other income, net, largely due to increased non-service cost components of net periodic benefit income not subject to formula rates or trackers (3 cents per share); and

•recovery of previously incurred expenses at Ameren Illinois Electric Distribution (2 cents per share).

Earnings per share in 2023, compared with 2022, were unfavorably affected by:

•decreased retail sales at Ameren Missouri and Ameren Illinois Natural Gas, primarily due to milder winter and summer temperatures as well as lower sales volumes, excluding the estimated effects of weather, in 2023 (estimated at 25 cents per share);

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•increased financing costs at Ameren (parent), Ameren Missouri, and Ameren Illinois Natural Gas, primarily due to higher interest rates on increased levels of short-term borrowings at Ameren (parent), and higher long-term debt balances and higher interest rates on short-term borrowings and long-term debt, partially offset by higher levels of allowance for funds used during construction, at Ameren Missouri and Ameren Illinois Natural Gas (13 cents per share);

•increased weighted-average basic common shares outstanding resulting from issuances of common shares as detailed in Note 5 – Long-term Debt and Equity Financings under Part II, Item 8, of this report (7 cents per share);

•increased depreciation and amortization expenses not recoverable under riders or trackers at Ameren Missouri and Ameren Illinois Natural Gas, primarily due to additional property, plant, and equipment investments (4 cents per share); and

•lower MEEIA 2019 performance incentives recognized at Ameren Missouri (3 cents per share).

The cents per share variances above are presented on the weighted-average basic shares outstanding in 2022 and do not reflect the impact of dilution on earnings per share, unless otherwise noted. The amounts above other than variances related to income taxes have been presented net of income taxes using Ameren’s 2023 blended federal and state statutory tax rate of 26%. For additional details regarding the Ameren Companies’ results of operations, including explanations of Electric and Natural Gas Margins, Other Operations and Maintenance Expenses, Depreciation and Amortization Expenses, Taxes Other Than Income Taxes, Other Income, Net, Interest Charges, and Income Taxes, see the major headings below.

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Below is Ameren’s table of income statement components by segment for the years ended December 31, 2023 and 2022:

Natural gas purchased for resale (79) — (276) — — (355)

Noncontrolling interests – preferred stock dividends (3) (1) — (1) — (5)

Natural gas purchased for resale (104) — (553) — — (657)

Noncontrolling interests – preferred stock dividends (3) (1) — (1) — (5)

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Below is Ameren Illinois’ table of income statement components by segment for the years ended December 31, 2023 and 2022:

Natural gas revenues — 897 — — 897

Natural gas purchased for resale — (276) — — (276)

Natural gas margins — 621 — — 621

Other operations and maintenance expenses (532) (237) (49) — (818)

Taxes other than income taxes (75) (67) (4) — (146)

Preferred stock dividends (1) — (1) — (2)

Net income attributable to common shareholder $ 258 $ 134 $ 215 $ — $ 607

Natural gas purchased for resale — (553) — — (553)

Natural gas margins — 627 — — 627

Other operations and maintenance expenses (580) (253) (49) — (882)

Depreciation and amortization (332) (98) (84) — (514)

Taxes other than income taxes (75) (82) (4) — (161)

Preferred stock dividends (1) — (1) — (2)

Net income attributable to common shareholder $ 202 $ 123 $ 188 $ — $ 513

Margins

Electric margins are defined as electric revenues less fuel and purchased power costs. Natural gas margins are defined as natural gas revenues less natural gas purchased for resale. We consider electric and natural gas margins useful measures to analyze the change in profitability of our electric and natural gas operations between periods. We have included the analysis below as a complement to the financial information we provide in accordance with GAAP. However, these margins may not be a presentation defined under GAAP, and they may not be comparable to other companies’ presentations or more useful than the GAAP information we provide elsewhere in this report.

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Electric Margins

Total by Segment(a) Increase (Decrease) by Segment

Overall Ameren Increase of $66 Million

(a)Includes other/intersegment eliminations of $(32) million and $(25) million in 2023and 2022, respectively.

Natural Gas Margins

Total by Segment(a) Decrease by Segment

Overall Ameren Decrease of $13 Million

(a)Includes other/intersegment eliminations of $(1) million and $(1) million in 2023and 2022, respectively.

Ameren Missouri Ameren Illinois Natural Gas Other/Intersegment Eliminations

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The following table presents the favorable (unfavorable) variations by segment for electric and natural gas margins in 2023, compared with 2022:

Electric and Natural Gas Margins

Electric revenue change:

Base rates (estimate)(b) $ 115 $ 30 $ — $ 62 $ — $ 207

Effect of weather (estimate)(c) (71) — — — — (71)

MEEIA 2019 performance incentives (10) — — — — (10)

Off-system sales, capacity, and FAC revenues, net (226) — — — — (226)

Transmission service charges (9) — — — — (9)

Other 1 (2) — — (7) (8)

Other cost recovery mechanisms(e) (10) (33) — — — (43)

Total electric revenue change $ (155) $ (38) $ — $ 62 $ (11) $ (142)

Fuel and purchased power change:

Effect of weather (estimate)(c) 14 — — — — 14

Effect of higher net energy costs included in base rates (21) — — — — (21)

Transmission service charges 4 — — — — 4

Cost recovery mechanisms – offset in electric revenue(d) (82) 51 — — 4 (27)

Total fuel and purchased power change $ 153 $ 51 $ — $ — $ 4 $ 208

Net change in electric margins $ (2) $ 13 $ — $ 62 $ (7) $ 66

Natural gas revenue change:

Base rates (estimate) $ — $ — $ 6 $ — $ — $ 6

Effect of weather (estimate)(c) (17) — — — — (17)

Sales volume (excluding the estimated effect of weather) — — (4) — — (4)

QIP rider — — 14 — — 14

Other (2) — (4) — — (6)

Other cost recovery mechanisms(e) (1) — (18) — — (19)

Total natural gas revenue change $ (32) $ — $ (283) $ — $ — $ (315)

Natural gas purchased for resale change:

Effect of weather (estimate)(c) $ 13 $ — $ — $ — $ — $ 13

Cost recovery mechanisms – offset in natural gas revenue(d) 12 — 277 — — 289

Total natural gas purchased for resale change $ 25 $ — $ 277 $ — $ — $ 302

Net change in natural gas margins $ (7) $ — $ (6) $ — $ — $ (13)

(a)Includes an increase in transmission electric margins of $56 million in 2023, compared with 2022, at Ameren Illinois.

(b)For Ameren Illinois Electric Distribution and Ameren Transmission, base rates include increases or decreases to operating revenues related to the revenue requirement reconciliation adjustment under formula rates. For Ameren Missouri, base rates exclude an increase for the recovery of lost electric margins resulting from the MEEIA customer energy-efficiency programs and a decrease in base rates for RESRAM. These changes in Ameren Missouri base rates are included in the “Sales volumes and changes in customer usage patterns (excluding the estimated effects of weather and MEEIA)” and “Cost recovery mechanisms - offset in fuel and purchased power” line items, respectively.

(c)Represents the estimated variation resulting primarily from changes in cooling and heating degree days on electric and natural gas demand compared with the prior year; this variation is based on temperature readings from the National Oceanic and Atmospheric Administration weather stations at local airports in our service territories.

(d)Electric and natural gas revenue changes are offset by corresponding changes in “Fuel,” “Purchased power,” and “Natural gas purchased for resale” on the statement of income, resulting in no change to electric and natural gas margins. Activity in Other/Intersegment Eliminations represents the elimination of related-party transactions between Ameren Missouri, Ameren Illinois, and ATXI, as well as Ameren Transmission revenue from transmission services provided to Ameren Illinois Electric Distribution. See Note 13 – Related-party Transactions and Note 16 – Segment Information under Part II, Item 8, of this report for additional information on intersegment eliminations.

(e)Offsetting expense increases or decreases are reflected in “Other operations and maintenance,” “Depreciation and amortization,” or in “Taxes other than income taxes” within the “Operating Expenses” section of the statement of income. These items have no overall impact on earnings.

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Ameren

Ameren’s electric margins increased $66 million, or 1%, in 2023, compared with 2022, because of increased margins at Ameren Transmission and Ameren Illinois Electric Distribution, as discussed below. Ameren’s natural gas margins decreased $13 million, or 2%, between years because of decreased margins at Ameren Missouri and Ameren Illinois Natural Gas, as discussed below.

Ameren Transmission

Ameren Transmission’s margins increased $62 million, or 10%, in 2023, compared with 2022. Base rate revenues were favorably affected by higher recoverable expenses (+$38 million) and increased capital investment (+$24 million), as evidenced by a 10% increase in rate base used to calculate the revenue requirement.

Ameren Missouri

Ameren Missouri’s electric margins were comparable between years. Revenues associated with “Cost recovery mechanisms – offset in fuel and purchased power” increased $82 million in 2023, compared with 2022, due to increased revenue related to the amortization of costs previously deferred under the FAC that were reflected in customer rates. The changes to “Cost recovery mechanisms - offset in fuel and purchased power” are fully offset by “Cost recovery mechanisms - offset in electric revenue,” in the table above, and result in no impact to margins. Ameren Missouri’s 5% exposure to net energy cost variances under the FAC is reflected within “Off-system sales, capacity, and FAC revenues, net” and “Energy costs (excluding the estimated effect of weather)”.

The following items had an unfavorable effect on Ameren Missouri’s electric margins in 2023, compared with 2022:

•Winter temperatures were warmer as heating degree days decreased 22% while spring and summer temperatures were milder as cooling degree days decreased 3%. The aggregate effect of weather decreased margins by an estimated $57 million. The change in margins due to weather is the sum of the “Effect of weather (estimate)” on electric revenues (-$71 million) and the “Effect of weather (estimate)” on fuel and purchased power (+$14 million) in the table above.

•Excluding the estimated effects of weather and the MEEIA customer energy-efficiency programs, electric revenues decreased an estimated $27 million resulting from a decrease in retail sales volumes, due, in part, to customer outages resulting from major storms experienced throughout the service territory in July and August 2023, partially offset by an increase in customer demand charge revenues and an increase in the average retail price per kilowatthour related to changes in customer usage patterns.

•MEEIA 2019 performance incentives decreased revenues $10 million as performance incentives for program years 2021 and 2022 were recognized in 2022, whereas the performance incentive for program year 2023 was recognized in 2023.

•Revenues associated with other cost recovery mechanisms decreased $10 million, primarily due to a decrease in RESRAM revenues, partially offset by an increase in excise taxes and recoverable MEEIA program costs.

•Transmission service charge revenues decreased $9 million, primarily due to lower revenues related to reactive power.

The following items had a favorable effect on Ameren Missouri’s electric margins in 2023, compared with 2022:

•Higher electric base rates, excluding the change in base rates for the MEEIA customer energy-efficiency programs and the RESRAM, resulting from the June 2023 MoPSC electric rate order effective July 9, 2023, partially offset by higher net energy costs included in base rates, increased margins an estimated $57 million. A similar effect resulting from the December 2021 MoPSC electric rate order effective February 28, 2022, increased margins an estimated $37 million. The change in electric base rates is the sum of the change in “Base rates (estimate)” (+$115 million) and the “Effect of higher net energy costs included in base rates” (-$21 million) in the table above.

•Ameren Missouri’s electric margins increased $12 million due to its 5% exposure to net energy cost variances under the FAC. The change in net energy costs is the sum of “Off-system sales, capacity and FAC revenues, net” (-$226 million) and “Energy costs (excluding the estimated effect of weather)” (+$238 million) in the table above. Revenues decreased primarily due to lower off-system sales volumes (-$108 million) related to reduced generation at the Rush Island Energy Center, lower capacity prices (-$101 million) set by the annual MISO auction in April 2023, and lower market prices for energy (-$11 million). Energy costs decreased primarily due to lower fuel costs (+$130 million), lower purchased power costs (+$98 million), and lower capacity costs (+$95 million), partially offset by decreased deferral of expenses under the FAC (-$90 million).

•Transmission service charge expenses decreased $4 million, primarily due to a decrease in charges related to transmission network upgrades.

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Ameren Missouri’s natural gas margins decreased $7 million, or 8%, in 2023, compared with 2022.Purchased gas costs decreased $12 million in 2023, compared with 2022, due to lower commodity prices and decreased amortization of deferred natural gas costs related to the extremely cold weather in mid-February 2021.The decreased purchased gas costs are fully offset by a decrease in natural gas revenues under the PGA, resulting in no impact to margin. The decrease in purchased gas cost is reflected in “Cost recovery mechanisms – offset in natural gas revenue” and the associated recoveries from customers is reflected in “Cost recovery mechanisms – offset in natural gas purchased for resale” in the table above. Margins decreased $4 million due to warmer winter temperatures as heating degree days decreased 22%. The change in margins due to weather is the sum of the “Effect of weather (estimate)” on natural gas revenues (-$17 million) and the “Effect of weather (estimate)” on natural gas purchased for resale (+$13 million) in the table above.

Ameren Illinois

Ameren Illinois’ electric margins increased $69 million, or 4%, in 2023, compared with 2022, driven by increased margins at Ameren Illinois Transmission and Ameren Illinois Electric Distribution. Ameren Illinois Natural Gas’ margins decreased $6 million, or 1%, between years.

Ameren Illinois Electric Distribution

Ameren Illinois Electric Distribution’s margins increased $13 million, or 1%, in 2023, compared with 2022. Purchased power costs decreased $51 million in 2023, compared with 2022, primarily due to decreased energy prices (-$54 million), which largely reflect the results of IPA procurement events, and lower volumes due to decreased sales (-$39 million), partially offset by increased revenues related to the amortization of costs previously deferred under riders (+$28 million) and higher costs due to higher capacity prices (+$9 million). The decreased purchased power costs are fully offset by a decrease in electric revenues under the cost recovery mechanisms for purchased power, resulting in no impact to margin. The decrease in purchased power cost is reflected in “Cost recovery mechanisms – offset in electric revenue” and the associated recoveries from customers is reflected in “Cost recovery mechanisms – offset in fuel and purchased power” in the table above.

The following items had a favorable effect on Ameren Illinois Electric Distribution’s margins in 2023, compared with 2022:

•The impact from base rates (+$30 million) increased due to a higher recognized ROE (+$21 million), as evidenced by an increase of 98 basis points in the annual average of the monthly yields of the 30-year United States Treasury bonds, and increased capital investment (+$15 million), as evidenced by a 9% increase in year-end rate base, partially offset by lower recoverable non-purchased power expenses (-$4 million), and the results from 2021 and 2022 revenue requirement reconciliation adjustment true-ups recognized in the subsequent year (-$2 million).

•Revenues associated with customer energy-efficiency program investments increased $18 million due to the recovery of program expenses (+$12 million), increased investment (+$2 million), higher recognized ROE under formula ratemaking (+$2 million), and the results from the 2022 revenue requirement reconciliation adjustment true-up recognized in 2023 (+$2 million).

Revenues associated with other cost recovery mechanisms decreased $33 million in 2023, compared with 2022, primarily due to a lower amount of bad debt costs included in customer rates pursuant to the associated rider.

Ameren Illinois Natural Gas

Ameren Illinois Natural Gas’ margins decreased $6 million, or 1%, in 2023, compared with 2022. Purchased gas costs decreased $277 million in 2023, compared with 2022, primarily due to lower amortization of natural gas costs that were previously deferred under the PGA and lower natural gas prices in 2023. Deferred natural gas costs related to the extremely cold weather in mid-February 2021 were fully recovered from customers by the end of 2022. The decreased purchased natural gas costs are fully offset by a decrease in natural gas revenues under the PGA, resulting in no impact to margin. The decrease in purchased gas cost is reflected in “Cost recovery mechanisms – offset in natural gas revenue” and the associated recoveries from customers is reflected in “Cost recovery mechanisms – offset in natural gas purchased for resale” in the table above.

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The following items had an unfavorable effect on Ameren Illinois Natural Gas’ margins in 2023, compared with 2022:

•Revenues associated with other cost recovery mechanisms decreased $18 million, primarily due to decreased revenues for excise taxes.

•Revenues decreased $4 million primarily due to lower sales volumes related to large commercial, industrial, and transportation customers, and lower capacity revenues. Revenues from sales to large commercial, industrial, and transportation customers are excluded from the VBA. See Note 2 - Rate and Regulatory Matters under Part II, Item 8, of this report for additional information regarding the VBA.

•Other miscellaneous revenues decreased $4 million primarily related to the refund of over-recovered costs associated with the COVID-19 pandemic, beginning in April 2023.

The following items had a favorable effect on Ameren Illinois Natural Gas’ margins in 2023, compared with 2022:

•Revenues increased $14 million due to additional investment in natural gas infrastructure under the QIP.

•Revenues increased $6 million due to higher natural gas base rates as a result of the natural gas rate order effective November 28, 2023.

See Note 2 – Rate and Regulatory Matters under Part II, Item 8, of this report for additional information regarding the QIP and 2023 Natural Gas Delivery Service Rate Order.

Ameren Illinois Transmission

Ameren Illinois Transmission’s electric margins increased $56 million, or 13%, in 2023, compared with 2022. Base rate revenues were favorably affected by increased capital investment (+$25 million), as evidenced by a 15% increase in rate base used to calculate the revenue requirement, and higher recoverable expenses (+$31 million).

Other Operations and Maintenance Expenses

Total by Segment(a) Increase (Decrease) by Segment

Overall Ameren Decrease of $71 Million

(a)Includes $60 million and $60 million at Ameren Transmission in 2023 and 2022, respectively, and other/intersegment eliminations of $34 million and $16 million in 2023and 2022, respectively.

Ameren Missouri Ameren Illinois Natural Gas Other/Intersegment Eliminations

Ameren Illinois Electric Distribution Ameren Transmission

Ameren

Other operations and maintenance expenses at Ameren decreased $71 million in 2023, compared with 2022. In addition to changes by segment as discussed below, other operations and maintenance expenses increased $18 million in 2023 for activity not reported as part of a

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segment, as reflected in “Other/Intersegment Eliminations” above, primarily because of an increase in the elimination of the non-service cost component of net periodic benefit income at Ameren Services. The non-service cost component of net periodic benefit cost or income at Ameren Services is allocated to the segments and primarily included in the segments’ other operations and maintenance expenses. Other operations and maintenance expenses were comparable at Ameren Transmission between periods.

Ameren Missouri

The $25 million decrease in Ameren Missouri’s other operations and maintenance expenses in 2023, compared with 2022, was primarily due to the following items:

•The cash surrender value of COLI increased $21 million. The effect of changes in the cash surrender value of COLI resulted in gains of $7 million in 2023, compared with losses of $14 million in 2022.

•The recognition of regulatory assets for previously expensed costs approved for recovery pursuant to the June 2023 MoPSC rate order decreased other operations and maintenance expenses $14 million.

•Renewable development costs decreased $9 million, as the MoPSC order approving CCNs for the Boomtown and Huck Finn solar projects in the first half of 2023 led to increased capitalization of renewable development costs pursuant to anticipated recovery from customers.

•Energy center operating and maintenance costs decreased $3 million, primarily because of the retirement of the Meramec Energy Center in December 2022, partially offset by increased costs related to maintenance outages at other energy centers.

The following items partially offset the above decreases in other operations and maintenance expenses between years:

•Transmission and distribution storm-related costs increased $7 million because of the major storms experienced throughout the service territory in July and August 2023.

•Transmission and distribution expenditures, excluding storm costs, increased $7 million, primarily because of increased inspection and vegetation management expenditures.

•MEEIA customer energy-efficiency program spend increased $3 million, as approved by the MoPSC.

Ameren Illinois

Other operations and maintenance expenses decreased $64 million at Ameren Illinois in 2023, compared with 2022, as discussed below. Other operations and maintenance expenses were comparable at Ameren Illinois Transmission between 2023 and 2022.

Ameren Illinois Electric Distribution

The $48 million decrease in Ameren Illinois Electric Distribution’s other operations and maintenance expenses in 2023, compared with 2022, was primarily due to the following items:

•Bad debt costs decreased $43 million primarily because of a lower amount of costs recovered from customers pursuant to the associated rider.

•The cash surrender value of COLI increased $10 million in 2023, primarily because of favorable market returns, compared with unfavorable market returns in 2022.

•Pension and benefit costs decreased $8 million, primarily related to decreased pension service costs due to changes in actuarial assumptions.

The following items partially offset the above decreases in other operations and maintenance expenses between years:

•Amortization of regulatory assets associated with customer energy-efficiency investments under formula ratemaking increased $9 million.

•Amortization of previously deferred storm-related costs and costs related to major storm activity in 2023, increased $6 million.

Ameren Illinois Natural Gas

Other operations and maintenance costs decreased $16 million in 2023, compared with 2022, in part, because of a $5 million increase in the cash surrender value of COLI. In 2023, the effect of changes in the cash surrender value of COLI resulted in a gain of $2 million, compared with a loss of $3 million in 2022. Other operations and maintenance expenses also decreased $5 million in 2023 because of a decline in required environmental remediation work. Additionally, other operations and maintenance expenses decreased $4 million, primarily related to labor overhead costs.

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Depreciation and Amortization

Total by Segment(a) Increase by Segment

Overall Ameren Increase of $98 Million

(a)Includes other/intersegment eliminations of $7 million and $4 million in 2023 and 2022, respectively.

Ameren Missouri Ameren Illinois Natural Gas Other/Intersegment Eliminations

Ameren Illinois Electric Distribution Ameren Transmission

The $98 million, $51 million, and $42 million increases in depreciation and amortization expenses in 2023, compared with 2022, at Ameren, Ameren Missouri, and Ameren Illinois, respectively, were primarily due to additional property, plant, and equipment across their respective segments.

In addition, Ameren’s and Ameren Missouri’s depreciation and amortization expenses were affected by the following, which include the effect of the additional investments in property, plant, and equipment:

•Increased depreciation and amortization of $51 million, due to the inclusion in base rates of amounts previously deferred under the PISA and RESRAM effective February 28, 2022, and July 9, 2023, pursuant to the December 2021 and June 2023 MoPSC electric rate orders, respectively.

•Depreciation and amortization rate changes pursuant to the electric rate orders noted above, which increased depreciation and amortization expenses by $17 million.

•Increased depreciation and amortization of $6 million, primarily because of electric system capital additions not eligible for deferral under PISA and RESRAM.

•The higher deferral, net of amortization of prior-period deferrals, pursuant to a tracker related to certain excess deferred income taxes, which decreased depreciation and amortization by $17 million.

•Depreciation and amortization expenses reflected a deferral to a regulatory asset of depreciation and amortization expenses pursuant to PISA and RESRAM. The amount of depreciation and amortization expenses included in base rates for PISA and RESRAM deferrals was updated when new customer rates became effective on February 28, 2022, pursuant to the December 2021 MoPSC electric rate order, which incorporated deferrals through September 30, 2021; and when new customer rates became effective July 9, 2023, pursuant to the June 2023 MoPSC electric rate order, which incorporated deferrals through December 31, 2022. The effect of higher deferrals, net of amortization of prior-period deferrals, decreased depreciation and amortization expenses by $5 million.

•The higher net under-recovery of RESRAM eligible expenses decreased depreciation and amortization expenses by $3 million.

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Taxes Other Than Income Taxes

Total by Segment(a) Increase (Decrease) by Segment

Overall Ameren Decrease of $17 Million

(a)Includes $8 million and $9 million at Ameren Transmission in 2023 and 2022, respectively, and other/intersegment eliminations of $12 million and $10 million in 2023and2022, respectively.

Ameren Missouri Ameren Illinois Natural Gas Other/Intersegment Eliminations

Ameren Illinois Electric Distribution Ameren Transmission

Taxes other than income taxes decreased $17 million in 2023, compared with 2022, largely because of a $14 million decrease in excise taxes at Ameren Illinois Natural Gas, primarily resulting from decreased sales revenues. Taxes other than income taxes also decreased $6 million and $2 million in 2023, at Ameren Missouri and Ameren Illinois, respectively, because of employee retention tax credits received under the Coronavirus Aid, Relief, and Economic Security Act. The decreases in taxes other than income taxes at Ameren Missouri were partially offset by a $4 million increase in excise taxes, primarily related to increased retail electric rates pursuant to the June 2023 MoPSC electric rate order.

See Excise Taxes in Note 15 – Supplemental Information under Part II, Item 8, of this report for additional information.

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Other Income, Net

Total by Segment Increase by Segment

Overall Ameren Increase of $122 Million

Ameren Missouri Ameren Illinois Natural Gas Other/Intersegment Eliminations

Ameren Illinois Electric Distribution Ameren Transmission

See Note 6 – Other Income, Net under Part II, Item 8, of this report for additional information. See Note 10 – Retirement Benefits under Part II, Item 8, of this report for more information on the non-service cost components of net periodic benefit income.

Ameren

Other income, net, increased $122 million in 2023, compared with 2022. In addition to changes discussed below, other income, net, increased $26 million, primarily because of a $30 million increase in the non-service cost component of net periodic benefit income for activity not reported as part of a segment, partially offset by a $3 million increase in charitable contributions.

Ameren Transmission

Other income, net, increased $11 million in 2023, compared with 2022, largely because of a $5 million increase in the allowance for equity funds used during construction, primarily resulting from a higher average monthly equity-to-debt ratio at ATXI, and higher average construction work in progress balances. Other income, net, also increased $3 million because of an increase in the non-service cost component of net periodic benefit income.

Ameren Missouri

Other income, net, increased $31 million in 2023, compared with 2022, primarily because of a $42 million increase in the non-service cost component of net periodic benefit income pursuant to the June 2023 MoPSC electric rate order, which reflected the effect of such increase in electric service rates effective July 9, 2023. Other income, net, also increased $6 million because of higher allowance for equity funds used during construction, resulting from higher average construction work in progress balances. Additionally, other income, net increased $6 million because of higher interest income on under-recovered asset balances associated with regulatory recovery mechanisms. These increases in other income, net, were partially offset by a decrease of $23 million in interest income on industrial development revenue bonds, as these bonds were settled in December 2022 and January 2023. See Note 5 – Long-term Debt and Equity Financings under Part II, Item 8, of this report for additional information on the termination of the financing obligation agreements related to the investments in industrial development revenue bonds.

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Ameren Illinois

Other income, net, increased $60 million in 2023, compared with 2022, primarily because of increases in the non-service cost component of net periodic benefit income of $26 million, $11 million, and $3 million at Ameren Illinois Electric Distribution, Ameren Illinois Natural Gas, and Ameren Illinois Transmission, respectively. Other income, net, also increased $13 million at Ameren Illinois Electric Distribution because of higher interest income on under-recovered balances associated with regulatory recovery mechanisms.

Interest Charges

Total by Segment Increase by Segment

Overall Ameren Increase of $80 Million

Ameren Missouri Ameren Illinois Natural Gas Other/Intersegment Eliminations

Ameren Illinois Electric Distribution Ameren Transmission

Interest charges increased $80 million in 2023, compared with 2022, primarily because of the following items:

See Note 4 – Short-term Debt and Liquidity under Part II, Item 8, of this report and the Long-term Debt and Equity section below for additional information on short-term borrowings and long-term debt, respectively, discussed below. See Note 5 – Long-term Debt and Equity Financings under Part II, Item 8, of this report for additional information on the termination of the financing obligation agreement discussed below.

Ameren

Interest charges increased $80 million in 2023, compared with 2022. In addition to changes by segments discussed below, interest charges increased $28 million for activity not reported as part of a segment, primarily because of a $23 million increase related to higher interest rates on increased levels of short-term borrowings at Ameren (parent). Interest charges for activity not reported as part of a segment also increased $5 million because of issuances of long-term debt at Ameren (parent) in November and December 2023.

Ameren Transmission

Interest charges increased $12 million in 2023, compared with 2022, primarily because of issuances of long-term debt in August and November 2022 and May 2023, which collectively increased interest charges by $17 million. The increases in 2023 were partially offset by a $8 million reduction to interest charges because of an increase in the borrowed funds capitalized as part of the allowance for funds used during construction, primarily due to increased average construction work in progress balances and a higher applicable borrowing rate.

Ameren Missouri

Interest charges increased $14 million in 2023, compared with 2022. The following items increased interest charges between years:

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•Issuances of long-term debt in April 2022 and March 2023 collectively increased interest charges by $27 million.

•Interest charges increased $11 million because of higher interest rates on increased levels of short-term borrowings.

•Interest charges reflected a deferral to a regulatory asset of interest charges pursuant to PISA and RESRAM. The amount of PISA and RESRAM deferrals included in base rates was updated when new customer rates became effective on February 28, 2022, pursuant to the December 2021 MoPSC electric rate order, which incorporated deferrals through September 30, 2021, and when new customer rates became effective July 9, 2023, pursuant to the June 2023 MoPSC electric rate order, which incorporated deferrals through December 31, 2022. Lower deferrals in 2023, due to the inclusion in base rates of interest associated with certain property, plant, and equipment previously deferred under the PISA and RESRAM, increased interest charges by $9 million.

The following items partially offset the above increases in interest charges between years:

•Interest charges decreased $23 million, primarily due to the termination of a financing obligation agreement related to the CT energy center in Audrain County. The decreases in interest charges associated with this agreement are offset by decreases in interest income on related industrial development revenue bonds, as discussed above.

•Interest charges decreased $14 million because of an increase in the borrowed funds capitalized as part of the allowance for funds used during construction, primarily due to higher average construction work in progress balances and a higher applicable borrowing rate.

Ameren Illinois

Interest charges increased $36 million in 2023, compared with 2022, primarily because of the issuances of long-term debt in 2022 and 2023. Issuances of long-term debt at Ameren Illinois in August and November 2022 and May 2023 collectively increased interest charges by $19 million at Ameren Illinois Electric Distribution, by $15 million at Ameren Illinois Transmission, and $12 million at Ameren Illinois Natural Gas. The increases in 2023 were partially offset by a $4 million reduction to interest charges at Ameren Illinois Transmission because of an increase in the borrowed funds capitalized as part of the allowance for funds used during construction, primarily due to higher average construction work in progress balances and a higher applicable borrowing rate.

Income Taxes

The following table presents effective income tax rates for the years ended December 31, 2023and 2022:

Ameren Missouri (2)% (2)%

Ameren Illinois 26% 26%

Ameren Illinois Electric Distribution 24% 25%

Ameren Illinois Natural Gas 27% 27%

Ameren Illinois Transmission 26% 26%

Ameren Transmission 26% 26%

See Note 12 – Income Taxes under Part II, Item 8, of this report for information regarding reconciliations of effective income tax rates for Ameren, Ameren Missouri, and Ameren Illinois.

LIQUIDITY AND CAPITAL RESOURCES

Collections from our tariff-based revenues are our principal source of cash provided by operating activities. A diversified retail customer mix, primarily consisting of rate-regulated residential, commercial, and industrial customers, provides us with a reasonably predictable source of cash. In addition to using cash provided by operating activities, we use 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 to support normal operations and temporary capital requirements. We may reduce our short-term borrowings with cash provided by operations or, at our discretion, with long-term borrowings, or, in the case of Ameren Missouri and Ameren Illinois, with capital contributions from Ameren (parent). In addition, to support a portion of its fuel requirements for generation, Ameren Missouri has entered into various long-term commitments to meet these requirements. Ameren Missouri and Ameren Illinois also have entered into various long-term commitments for purchased power and natural gas for distribution. Ameren’s, Ameren Missouri’s, and Ameren Illinois’ estimated minimum purchase obligations associated with these commitments totaled $2.3 billion, $1.1 billion, and, $1.2 billion, respectively, which include $0.9 billion, $0.4 billion, and, $0.6 billion, respectively, in 2024.

We expect to make significant capital expenditures over the next five years, as discussed in the Capital Expenditures sections below, supported by a combination of long-term debt and equity, as we invest in our electric and natural gas utility infrastructure to support overall system reliability, grid modernization, renewable energy target requirements, environmental compliance, and other improvements. For additional information about our long-term debt outstanding, including maturities due within one year, and the applicable interest rates, see

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Note 5 – Long-term Debt and Equity Financings under Part II, Item 8, of this report. As part of its funding plan for capital expenditures, Ameren is using newly issued shares of common stock to satisfy requirements under the DRPlus and employee benefit plans and expects to continue to do so through at least 2028. Additionally, Ameren has an ATM program under which Ameren may offer and sell from time to time common stock, which includes the ability to enter into forward sale agreements, subject to market conditions and other factors. During 2023, Ameren issued a total of 3.2 million shares of common stock and received aggregate proceeds of $299 million under the ATM program. As of December 31, 2023, Ameren had multiple forward sale agreements that could be settled under the ATM program with various counterparties relating to 2.9 million shares of common stock. Ameren expects to settle approximately $230 million of the forward sale agreements with physical delivery of 2.9 million shares of common stock by December 31, 2024. Including issuances under the DRPlus and employee benefit plans, Ameren plans to issue approximately $300 million of equity in 2024 and approximately $600 million of equity each year from 2025 to 2028. As of December 31, 2023, Ameren had approximately $770 million of common stock available for sale under the ATM program, which takes into account the forward sale agreements in effect as of December 31, 2023. Ameren expects its equity to total capitalization to support solid investment-grade credit ratings. See Note 5 – Long-term Debt and Equity Financings under Part II, Item 8, of this report for additional information on the ATM program, including the forward sale agreements under the ATM program relating to common stock.

The following table presents net cash provided by (used in) operating, investing, and financing activities for the years ended December 31, 2023 and 2022:

(a) Both Ameren and Ameren Illinois’ cash provided by operating activities included cash outflows of $123 million and $104 million for the FEJA electric energy-efficiency rider and $9 million and $5 million for the customer generation rebate program in 2023 and 2022, respectively.

Cash Flows from Operating Activities

Our cash provided by operating activities is affected by fluctuations of trade accounts receivable, inventories, and accounts and wages payable, among other things, as well as the unique regulatory environment for each of our businesses. Substantially all expenditures related to fuel, purchased power, and natural gas purchased for resale are recovered from customers through rate adjustment mechanisms, which may be adjusted without a traditional regulatory rate review, subject to prudence reviews. Similar regulatory mechanisms exist for certain other operating expenses that can also affect the timing of cash provided by operating activities. The timing of cash payments for costs recoverable under our regulatory mechanisms differs from the recovery period of those costs. Additionally, the seasonality of our electric and natural gas businesses, primarily caused by seasonal customer rates and changes in customer demand due to weather, significantly affects the amount and timing of our cash provided by operating activities. See Note 2 – Rate and Regulatory Matters under Part II, Item 8, of this report for more information about our regulatory frameworks.

As a result of the significant increase in customer demand and prices for natural gas and electricity experienced in mid-February 2021 due to extremely cold weather, Ameren Missouri and Ameren Illinois had under-recovered costs for the month of February 2021 under their PGA clauses and, for Ameren Missouri, under the FAC (Ameren Missouri - PGA $53 million, FAC $50 million; Ameren Illinois - PGA $221 million). Ameren Missouri’s PGA under-recovery is being collected from customers over 36 months beginning November 2021, pursuant to an October 2021 MoPSC order, and the FAC under-recovery was collected over eight months beginning October 2021. Ameren Illinois collected the PGA under-recovery over 18 months beginning April 2021.

Ameren

Ameren’s cash provided by operating activities increased $301 million in 2023, compared with 2022. The following items contributed to the increase:

•A $372 million increase in customer collections, primarily from base rate increases effective February 28, 2022, and July 9, 2023, pursuant to Ameren Missouri’s December 2021 and June 2023 MoPSC electric rate orders, respectively, electric transmission rate base growth, and an increase attributable to non-PGA regulatory mechanisms, partially offset by a decrease under Ameren Illinois’ PGA resulting from the 2022 recovery of costs for the mid-February 2021 weather event discussed above.

•A $211 million decrease in net collateral posted with counterparties, primarily due to changes in the market prices of power, natural gas, and other fuels.

•A $66 million decrease in the cost of natural gas held in storage, primarily at Ameren Illinois, because of lower commodity prices.

The following items partially offset the increase in Ameren’s cash from operating activities between periods:

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•A $70 million increase in interest payments, primarily due to an increase in the average outstanding debt and an increase in interest rates. This $70 million increase in interest payments includes a $24 million decrease in interest payments from financing obligations at Ameren Missouri that were settled in December 2022 and January 2023. See Note 5 – Long-term Debt and Equity Financings under Part II, Item 8, of this report for additional information on the termination of the financing obligation agreements.

•A $65 million increase in coal inventory levels at Ameren Missouri, primarily due to fewer transportation delays and less coal burned in 2023 as a result of decreased generation volumes, which were affected by reduced generation at the Rush Island Energy Center, lower market prices for capacity and energy, and decreased retail load because of warmer winter and milder spring and summer temperatures.

•A $35 million increase in labor costs and payments to contractors primarily due to major storm restoration costs, primarily at Ameren Illinois, due to major storms in late June, July, and August 2023.

•A $25 million decrease due to the timing of payments for accounts payable and prepaid expenses.

•A $25 million decrease due to the timing of payments received from the DOE for the annual reimbursement of spent nuclear fuel storage and related costs.

•A $24 million decrease in interest collections on industrial revenue bonds at Ameren Missouri, as these bonds were settled in December 2022 and January 2023. See Note 5 – Long-term Debt and Equity Financings under Part II, Item 8, of this report for additional information on the termination of the financing obligation agreements related to the investments in industrial development revenue bonds.

•A $23 million increase in workers’ compensation payments at Ameren Illinois.

•An $11 million increase in property tax payments at Ameren Missouri, primarily due to higher assessed property tax values.

Ameren Missouri

Ameren Missouri’s cash provided by operating activities increased $211 million in 2023, compared with 2022. The following items contributed to the increase:

•A $239 million increase in customer collections, primarily from base rate increases effective February 28, 2022, and July 9, 2023, pursuant to the December 2021 and June 2023 MoPSC electric rate orders, respectively, and an increase attributable to regulatory mechanisms.

•A $131 million decrease in net collateral posted with counterparties, primarily due to changes in the market prices of power, natural gas, and other fuels.

•A $5 million decrease in interest payments, primarily due to a $24 million decrease in interest payments from financing obligations that were settled in December 2022 and January 2023. See Note 5 – Long-term Debt and Equity Financings under Part II, Item 8, of this report for additional information on the termination of the financing obligation agreements, partially offset by an increase in interest payments due to an increase in the average outstanding debt and an increase in interest rates.

The following items partially offset the increase in Ameren Missouri’s cash from operating activities between periods:

•A $65 million increase in coal inventory levels, primarily due to fewer transportation delays and less coal burned in 2023 as a result of decreased generation volumes, which were affected by reduced generation at the Rush Island Energy Center, lower market prices for capacity and energy, and decreased retail load because of warmer winter and milder spring and summer temperatures.

•A $25 million decrease due to the timing of payments received from the DOE for the annual reimbursement of spent nuclear fuel storage and related costs.

•A $24 million decrease in interest collections on industrial revenue bonds, as these bonds were settled in December 2022 and January 2023. See Note 5 – Long-term Debt and Equity Financings under Part II, Item 8, of this report for additional information on the termination of the financing obligation agreements related to the investments in industrial development revenue bonds.

•A $16 million decrease due to the timing of payments for accounts payable and prepaid expenses.

•An $11 million increase in property tax payments, primarily due to higher assessed property tax values.

•A $7 million increase in major storm restoration costs, primarily due to major storms in July and August 2023.

Ameren Illinois

Ameren Illinois’ cash provided by operating activities increased $50 million in 2023, compared with 2022. The following items contributed to the increase:

•A $145 million increase in customer collections, primarily from electric transmission rate base growth and an increase attributable to non-PGA regulatory recovery mechanisms, partially offset by a decrease under the PGA resulting from the recovery in 2022 of costs for the mid-February 2021 weather event discussed above.

•An $83 million decrease in net collateral posted with counterparties, primarily due to changes in the market prices of power and natural gas.

•A $63 million decrease in the cost of natural gas held in storage because of lower commodity prices.

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The following items partially offset the increase in Ameren Illinois’ cash from operating activities between periods:

•A $79 million decrease resulting from income tax payments to Ameren (parent) pursuant to the tax allocation agreement, primarily due to higher taxable income in 2023.

•A $64 million decrease due to the timing of payments for accounts payable and prepaid expenses.

•A $43 million increase in interest payments, primarily due to an increase in the average outstanding debt and an increase in interest rates.

•A $28 million increase in labor costs and payments to contractors primarily due to major storm restoration costs due to major storms in late June, July, and August 2023.

•A $23 million increase in workers’ compensation payments.

Cash Flows from Investing Activities

Ameren’s cash used in investing activities increased $428 million during 2023, compared with 2022, primarily as a result of a $246 million increase in capital expenditures, largely resulting from increased storm-related expenditures at Ameren Missouri and Ameren Illinois and electric transmission upgrades at ATXI. ATXI’s capital expenditures increased $56 million. Also, cash used in investing activities increased at Ameren Missouri, due to increased nuclear fuel expenditures of $145 million and the absence of receipt of $21 million in insurance proceeds in 2022 for the Callaway Energy Center’s generator.

Ameren Missouri’s cash used in investing activities increased $257 million during 2023, compared with 2022, primarily due to increased nuclear fuel expenditures for future refuels of $174 million in 2023 compared to $29 million in 2022. Also, cash used in investing activities increased $70 million as a result of increased capital expenditures, largely resulting from an increase in storm-related expenditures of $58 million. In addition, cash used in investing activities increased due to the absence of receipt of $21 million in insurance proceeds in 2022 for the Callaway Energy Center’s generator.

Ameren Illinois’ cash used in investing activities increased $131 million during 2023, compared with 2022, due to an increase in capital expenditures, largely resulting from increased storm-related expenditures of $103 million.

Capital Expenditures

The following charts present our capital expenditures for the years ended December 31, 2023 and 2022:

Ameren Illinois Electric Distribution Ameren Illinois Transmission

(a)Includes Other capital expenditures of $(18) million and $(9) million for the years ended December 31, 2023 and 2022, respectively, which includes amounts for the elimination of intercompany transfers.

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Ameren’s 2023 capital expenditures consisted of expenditures made by its subsidiaries, including $124 million by ATXI and other electric transmission subsidiaries. Ameren Illinois Natural Gas capital expenditures for 2023 included $165 million related to natural gas projects eligible for QIP recovery. Ameren’s 2022 capital expenditures consisted of expenditures made by its subsidiaries, including $69 million by ATXI and other electric transmission subsidiaries. Ameren Illinois Natural Gas capital expenditures for 2022 included $183 million related to natural gas projects eligible for QIP recovery. In both years, other capital expenditures were made principally to maintain, upgrade, and improve the reliability of the transmission and distribution systems of Ameren Missouri and Ameren Illinois by investing in substation upgrades, energy center projects, and smart-grid technology. Additionally, the Ameren Companies invested in various software projects.

The following table presents Ameren’s estimate of capital expenditures that will be incurred from 2024 through 2028, including construction expenditures, allowance for funds used during construction, and expenditures for compliance with existing environmental regulations:

Ameren Missouri’s estimated capital expenditures include transmission, distribution, grid modernization, and generation-related investments, including $3.3 billion of renewable generation investments and $2.7 billion of dispatchable generation investments through 2028, consistent with Ameren Missouri’s 2023 IRP, as well as expenditures for compliance with environmental regulations. Capital expenditures related to coal-fired generation of approximately $0.9 billion are included in Ameren Missouri’s estimated capital expenditures through 2028. Ameren Illinois’ estimated capital expenditures are primarily for electric and natural gas transmission and distribution-related investments, including investmentsto meet compliance requirements of the CEJA, while continuing to ensure safe and adequate service is maintained. Ameren Illinois’ estimates may be revised as a result of future ICC orders related to its MYRP.

Ameren Missouri continually reviews its generation portfolio and expected power needs. As a result, Ameren Missouri could modify its plan for generation capacity, the type of generation asset technology that will be employed, and whether capacity or power may be purchased, among other changes. Additionally, we continually review the reliability of our transmission and distribution systems, expected capacity needs, and opportunities for transmission investments within and outside our service territories. The timing and amount of investments could vary because of changes in expected capacity, the condition of transmission and distribution systems, future rate orders, and our ability and willingness to pursue transmission investments, as well as our ability to obtain necessary regulatory approvals, among other factors. Any changes in future generation, transmission, or distribution needs could result in significant changes in capital expenditures or losses, which could be material. Compliance with environmental regulations could also have significant impacts on the level of capital expenditures.

Environmental Capital Expenditures

Ameren Missouri will continue to incur costs to comply with federal and state regulations, including those requiring the reduction of SO2, NOx, and mercury emissions from its coal-fired energy centers, compliance with the CCR Rule, and potential modifications to cooling water

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intake structures at existing power plants under Clean Water Act rules. See Note 14 – Commitments and Contingencies under Part II, Item 8, of this report for a discussion of existing and proposed environmental laws that affect, or may affect, our facilities and capital expenditures to comply with such laws.

Cash Flows from Financing Activities

Cash provided by, or used in, financing activities is a result of our financing needs, which depend on the level of cash provided by operating activities, the level of cash used in investing activities, the level of dividends, and our long-term debt maturities, among other things.

Ameren’s cash provided by financing activities increased $122 million during 2023, compared with 2022. During 2023, Ameren utilized net proceeds of $2.3 billion of long-term debt for general corporate purposes, for capital expenditures, to repay then-outstanding short-term debt, and to repay $100 million of maturities of long-term debt. Ameren also repaid net commercial paper borrowings totaling $533 million. In addition, Ameren utilized aggregate cash proceeds of $346 million from the issuance of common stock under the ATM program, the DRPlus, and the 401(k) plan, and cash provided by operating activities to fund, in part, capital expenditures. In comparison, in 2022, Ameren utilized proceeds from the issuance of $1.5 billion of long-term debt to repay then-outstanding short-term debt, for capital expenditures, and to repay $505 million of maturities of long-term debt. Ameren also received aggregate cash proceeds of $333 million from the issuance of common stock under the ATM program, the DRPlus, and the 401(k) plan, and $522 million from net commercial paper issuances. These proceeds were used to fund, in part, capital expenditures. During 2023, Ameren paid common stock dividends of $662 million, compared with $610 million in dividend payments in 2022.

Ameren Missouri’s cash provided by financing activities increased $38 million during 2023, compared with 2022. During 2023, Ameren Missouri utilized net proceeds of $499 million from the issuance of long-term debt for capital expenditures and to repay then-outstanding short-term debt. Ameren Missouri also repaid net commercial paper borrowings totaling $159 million. In addition, Ameren Missouri utilized net proceeds of $306 million from money pool borrowings along with cash provided by operating activities to fund, in part, capital expenditures. In comparison, in 2022, Ameren Missouri utilized net proceeds of $524 million from the issuance of long-term debt to repay then-outstanding short-term debt and for capital expenditures. Ameren Missouri also utilized proceeds from net commercial paper issuances of $164 million along with cash provided by operating activities to fund, in part, capital expenditures. During 2023, Ameren Missouri paid common stock dividends of $9 million, compared with $46 million in dividend payments in 2022.

Ameren Illinois’ cash provided by financing activities increased $66 million during 2023, compared with 2022. During 2023, Ameren Illinois utilized net proceeds of $498 million from the issuance of long-term debt to repay then-outstanding short-term debt and $100 million of long-term debt maturities. In addition, Ameren Illinois utilized proceeds from net commercial paper issuances of $102 million, proceeds of $135 million from money pool borrowings, and capital contributions from Ameren (parent) of $91 million along with cash provided by operating activities to fund, in part, capital expenditures. In comparison, in 2022, Ameren Illinois utilized net proceeds of $848 million from the issuance of long-term debt to repay $400 million of maturities of long-term debt and to repay a portion of then-outstanding short-term debt. Additionally, the proceeds from the issuance of long-term debt, proceeds from net commercial paper issuances of $161 million, capital contributions from Ameren (parent) of $15 million, and cash provided by operating activities were used to fund, in part, capital expenditures. During 2023, Ameren Illinois paid common stock dividends of $41 million.

Credit Facility Borrowings and Liquidity

The liquidity needs of the Ameren Companies are typically 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. See Note 4 – Short-term Debt and Liquidity under Part II, Item 8, of this report for additional information on credit agreements, commercial paper issuances, Ameren’s money pool arrangements and related borrowings, and relevant interest rates.

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The following table presents Ameren’s consolidated net available liquidity as of December 31, 2023:

Ameren (parent) and Ameren Missouri(a):

Missouri Credit Agreement – borrowing capacity $ 1,400

Less: Ameren Missouri commercial paper outstanding 170

Less: Letters of credit 2

Missouri Credit Agreement – subtotal 1,228

Ameren (parent) and Ameren Illinois(b):

Illinois Credit Agreement – borrowing capacity 1,200

Less: Ameren Illinois commercial paper outstanding 366

Illinois Credit Agreement – subtotal 834

Cash and cash equivalents 25

Net available liquidity $ 2,087

(a) The maximum aggregate amount available to both Ameren (parent) and Ameren Missouri under the Missouri Credit Agreement is $1 billion.

(b) The maximum aggregate amount available to Ameren (parent) and Ameren Illinois under the Illinois Credit Agreement is $700 million and $1 billion, respectively.

The Credit Agreements, among other things, provide $2.6 billion of credit until maturity in December 2027. See Note 4 – Short-term Debt and Liquidity under Part II, Item 8, of this report for additional information on the Credit Agreements. During the year ended December 31, 2023, Ameren (parent), Ameren Missouri, and Ameren Illinois each issued commercial paper. Borrowings under the Credit Agreements and commercial paper issuances are based upon available interest rates at that time of the borrowing or issuance.

Ameren has a money pool agreement with and among its utility subsidiaries to coordinate and to provide for certain short-term cash and working capital requirements. As short-term capital needs arise, and based on availability of funding sources, Ameren Missouri and Ameren Illinois will access funds from the utility money pool, the Credit Agreements, or the commercial paper programs depending on which option has the lowest interest rates.

The issuance of short-term debt securities by Ameren’s utility subsidiaries is subject to FERC approval under the Federal Power Act. In January 2023, the FERC issued orders authorizing Ameren Missouri, Ameren Illinois, and ATXI to issue up to $1 billion, $1 billion, and $300 million, respectively, of short-term debt securities through January 2025.

The Ameren Companies continually evaluate the adequacy and appropriateness of their liquidity arrangements for changing business conditions. When business conditions warrant, changes may be made to existing credit agreements or to other short-term borrowing arrangements, or other arrangements may be made.

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Long-term Debt and Equity

The following table presents Ameren’s issuances (net of any issuance premiums or discounts) of long-term debt and equity, as well as redemptions and maturities of long-term debt for the years ended December 31, 2023 and 2022. For additional information related to the terms and uses of these issuances and effective registration statements, and Ameren’s forward sale agreements relating to common stock, see Note 5 – Long-term Debt and Equity Financings under Part II, Item 8, of this report. For information on capital contributions received by Ameren Missouri and Ameren Illinois from Ameren (parent), see Note 13 – Related-party Transactions under Part II, Item 8, of this report.

Month Issued, Redeemed, Repurchased, or Matured 2023 2022

Issuances of Long-term Debt

Ameren:

5.70% Senior unsecured notes due 2026 November $ 599 $ —

5.00% Senior unsecured notes due 2029 December 699 —

Ameren Missouri:

Ameren Illinois:

5.90% First mortgage bonds due 2052(a) November — 349

ATXI:

2.96% Senior unsecured notes Series B due 2052 August — 95

Total Ameren long-term debt issuances $ 2,295 $ 1,467

Issuances of Common Stock

Ameren:

DRPlus and 401(k)(b)(c) Various $ 47 $ 41

Total Ameren common stock issuances(e) $ 346 $ 333

Maturities of Long-term Debt

Ameren Missouri:

Audrain County agreement (Audrain County CT) due 2023 January $ 240 $ —

City of Bowling Green financing obligation (Peno Creek CT) December — 8

Ameren Illinois:

2.70% Senior secured notes due 2022 September — 400

ATXI:

3.43% Senior unsecured notes due 2050 August — 50

Total long-term debt redemptions, repurchases, and maturities $ 340 $ 505

(a) Ameren Missouri and Ameren Illinois intend to allocate an amount equal to the net proceeds to sustainability projects meeting certain eligibility criteria.

(b) Ameren issued a total of 0.6 million and 0.5 million shares of common stock under its DRPlus and 401(k) plan in 2023 and 2022, respectively.

(d) Ameren issued 3.2 million and 3.4 million shares of common stock under the ATM program in 2023 and 2022, respectively.

(e) Excludes 0.5 million and 0.4 million shares of common stock valued at $40 million and $31 million issued for no cash consideration in connection with stock-based compensation in 2023 and 2022, respectively.

In January 2024, Ameren Missouri issued $350 million of 5.25% first mortgage bonds due January 2054, with interest payable semiannually on January 15 and July 15 of each year, beginning July 15, 2024. Net proceeds from this issuance were used for capital expenditures and to repay short-term debt.

The Ameren Companies may sell securities registered under their effective registration statements if market conditions and capital requirements warrant such sales. Any offer and sale will be made only by means of a prospectus that meets the requirements of the Securities Act of 1933 and the rules and regulations thereunder.

Indebtedness Provisions and Other Covenants

At December 31, 2023, the Ameren Companies were in compliance with the provisions and covenants contained within their credit agreements, indentures, and articles of incorporation, as applicable, and ATXI was in compliance with the provisions and covenants contained in its note purchase agreements. See Note 4 – Short-term Debt and Liquidity and Note 5 – Long-term Debt and Equity Financings

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under Part II, Item 8, of this report for a discussion of covenants and provisions (and applicable cross-default provisions) contained in our credit agreements, certain of the Ameren Companies’ indentures and articles of incorporation, and ATXI’s note purchase agreements.

We consider access to short-term and long-term capital and credit markets to be a significant source of funding for capital requirements not satisfied by cash provided by our operating activities. Inability to raise capital on reasonable terms, particularly during times of uncertainty in the capital and credit markets, could negatively affect our ability to maintain and expand our businesses. After assessing its current operating performance, liquidity, and credit ratings (see Credit Ratings below), Ameren, Ameren Missouri, and Ameren Illinois each believes that it will continue to have access to the capital and credit markets on reasonable terms. However, events beyond Ameren’s, Ameren Missouri’s, and Ameren Illinois’ control may create uncertainty in the capital and credit markets or make access to the capital and credit markets uncertain or limited. Such events could increase our cost of capital and adversely affect our ability to access the capital and credit markets.

Dividends

Ameren paid to its shareholders common stock dividends totaling $662 million, or $2.52 per share, in 2023 and $610 million, or $2.36 per share, in 2022. The amount and timing of dividends payable on Ameren’s common stock are within the sole discretion of Ameren’s board of directors. Ameren’s board of directors has not set specific targets or payout parameters when declaring common stock dividends, but it considers various factors, including Ameren’s overall payout ratio, payout ratios of our peers, projected cash flow and potential future cash flow requirements, historical earnings and cash flow, projected earnings, impacts of regulatory orders or legislation, and other key business considerations. Ameren expects its dividend payout ratio to be between 55% and 65% of earnings over the next few years. On February 9, 2024, the board of directors of Ameren declared a quarterly dividend on Ameren’s common stock of 67 cents per share, payable on March 29, 2024, to shareholders of record on March 13, 2024.

Certain of our financial agreements and corporate organizational documents contain covenants and conditions that, among other things, restrict the Ameren Companies’ payment of dividends in certain circumstances.

Ameren Illinois’ articles of incorporation require its dividend payments on common stock to be based on ratios of common stock to total capitalization and other provisions with respect to certain operating expenses and accumulations of earned surplus. Additionally, Ameren has committed to the FERC to maintain a minimum of 30% equity in the capital structure at Ameren Illinois.

Ameren Missouri and Ameren Illinois, as well as certain other nonregistrant Ameren subsidiaries, are subject to Section 305(a) of the Federal Power Act, which makes it unlawful for any officer or director of a public utility, as defined in the Federal Power Act, to participate in the making or paying of any dividend from any funds “properly included in capital account.” The FERC has consistently interpreted the provision to allow dividends to be paid as long as (1) the source of the dividends is clearly disclosed, (2) the dividends are not excessive, and (3) there is no self-dealing on the part of corporate officials. At a minimum, Ameren believes that dividends can be paid by its subsidiaries that are public utilities from net income and from retained earnings. In addition, under Illinois law, Ameren Illinois and ATXI may not pay any dividend on their respective stock unless, among other things, their respective earnings and earned surplus are sufficient to declare and pay a dividend after provisions are made for reasonable and proper reserves, or unless Ameren Illinois or ATXI has specific authorization from the ICC.

At December 31, 2023, the amount of restricted net assets of Ameren’s subsidiaries that may not be distributed to Ameren in the form of a loan or dividend was $4.6 billion.

The following table presents common stock dividends declared and paid by Ameren Corporation to its common shareholders and by Ameren subsidiaries to their parent, Ameren:

Ameren Missouri 9 46

Ameren Illinois 41 —

Ameren Missouri and Ameren Illinois each have issued preferred stock, which provide for cumulative dividends. Each company’s board of directors considers the declaration of preferred stock dividends to shareholders of record on a certain date, stating the date on which the dividend is payable and the amount to be paid. See Note 5 – Long-term Debt and Equity Financings under Part II, Item 8, of this report for further detail concerning the preferred stock issuances.

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Credit Ratings

Our credit ratings affect our liquidity, our access to the capital and credit markets and credit markets, our cost of borrowing under our credit facilities and our commercial paper programs, and our collateral posting requirements under commodity contracts.

The following table presents the principal credit ratings of the Ameren Companies by Moody’s and S&P effective on the date of this report:

Moody’s S&P

Ameren:

Issuer/corporate credit rating Baa1 BBB+

Senior unsecured debt Baa1 BBB

Commercial paper P-2 A-2

Ameren Missouri:

Issuer/corporate credit rating Baa1 BBB+

Senior debt A2 A

Senior unsecured debt Baa1 Not Rated

Commercial paper P-2 A-2

Ameren Illinois:

Issuer/corporate credit rating A3 BBB+

Senior debt A1 A

Senior unsecured debt A3 BBB+

Commercial paper P-2 A-2

ATXI:

Issuer credit rating A2 Not Rated

Senior unsecured debt A2 Not Rated

A credit rating is not a recommendation to buy, sell, or hold securities. It should be evaluated independently of any other rating. Ratings are subject to revision or withdrawal at any time by the rating organization.

Collateral Postings

Any weakening of our credit ratings may reduce access to capital and trigger additional collateral postings and prepayments. Such changes may also increase the cost of borrowing, resulting in an adverse effect on earnings. Cash collateral postings and prepayments made with external parties, including postings related to exchange-traded contracts, were immaterial, and cash collateral posted by external parties were $53 million for Ameren and Ameren Illinois at December 31, 2023. A sub-investment-grade issuer or senior unsecured debt rating (below “Baa3” from Moody’s or below “BBB-” from S&P) at December 31, 2023, could have resulted in Ameren, Ameren Missouri, or Ameren Illinois being required to post additional collateral or other assurances for certain trade and contractual obligations amounting to $685 million, $604 million, and $81 million, respectively.

Changes in commodity prices could trigger additional collateral postings and prepayments. Based on credit ratings at December 31, 2023, if market prices were 15% higher or lower than December 31, 2023 levels in the next 12 months and 20% higher or lower thereafter through the end of the term of the commodity contracts, then Ameren, Ameren Missouri, or Ameren Illinois could be required to post an immaterial amount, compared to each company’s liquidity, of collateral or provide other assurances for certain trade and contractual obligations.

Environmental Matters

Our 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 address air emissions; discharges to water bodies; the storage, handling and disposal of hazardous substances and waste materials; siting and land use requirements; and potential ecological impacts. See Note 14 – Commitments and Contingencies under Part II, Item 8, of this report for a discussion of existing and proposed environmental laws, including those that relate to climate change, that affect, or may affect, our facilities, operations, and capital expenditures to comply with such laws. The individual or combined effects of compliance with existing and new environmental regulations could result in significant capital expenditures, increased operating costs, or the closure or alteration of operations at some of Ameren Missouri’s energy centers.

Additionally, international agreements could lead to future federal or state legislation or regulations. In 2015, the United Nations Framework Convention on Climate Change reached consensus among approximately 190 nations on an agreement, known as the Paris

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Agreement, that establishes a framework for greenhouse gas mitigation actions by all countries, with a goal of holding the increase in global average temperature to below 2 degrees Celsius above pre-industrial levels and an aspiration to limit the increase to 1.5 degrees Celsius. The Biden administration made a policy commitment regarding a reduction in greenhouse gas emissions for the United States, but rulemaking to achieve such reductions has not yet been implemented. Actions taken to implement the Paris Agreement could result in future additional greenhouse gas reduction requirements in the United States. In addition, the EPA has announced plans to implement new climate change programs, including potential regulation of greenhouse gas emissions from the utility industry.

We provide information regarding our sustainability initiatives through our website, including in our annual sustainability report, our responses to the annual climate change and water surveys conducted by CDP, and a sustainability investor presentation. In addition, we issue an annual report in accordance with the Edison Electric Institute’s (EEI) and American Gas Association’s (AGA) ESG and sustainability-related reporting program. We also issue a periodic climate risk report and a report on our management of CCR. Additionally, we have posted a Task Force on Climate-related Financial Disclosures (TCFD) and Sustainability Accounting Standards Board (SASB) mapping of sustainability data. The reports may be updated at any time. The information on Ameren’s website, including the reports and documents mentioned in this paragraph, is not incorporated by reference into this report.

OUTLOOK

Below are some key trends, events, and uncertainties that may reasonably affect our results of operations, financial condition, or liquidity, as well as our ability to achieve strategic and financial objectives, for 2024 and beyond. For additional information regarding recent rate orders, lawsuits, and pending requests filed with state and federal regulatory commissions, including those discussed below, see Note 2 – Rate and Regulatory Matters under Part II, Item 8, of this report.

Operations

•We are observing inflationary pressures on the prices of labor, services, materials, and supplies, as well as high interest rates. Ameren Missouri and Ameren Illinois are generally allowed to pass on to customers prudently incurred costs for fuel, purchased power, and natural gas supply. Additionally, for certain non-commodity cost changes, the use of trackers, riders, formula ratemaking, and future test years, as applicable, mitigates our exposure. The inflationary pressures and high interest rates could impact our ability to control costs and/or 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 rates that are affordable to our customers. In addition, these inflationary pressures and high interest rates could adversely affect our customers’ usage of, or payment for, our services.

•The PISA permits Ameren Missouri to defer and recover 85% of the depreciation expense for investments in qualifying property, plant, and equipment placed in service and not included in base rates. Investments not eligible for recovery under the PISA include amounts related to new nuclear and natural gas generating units and service to new customer premises. Additionally, the PISA permits Ameren Missouri to earn a return at the applicable WACC on rate base that incorporates those qualifying investments, as well as changes in total accumulated depreciation excluding retirements and plant-related deferred income taxes since the previous regulatory rate review. The regulatory asset for accumulated PISA deferrals also earns a return at the applicable WACC until added to rate base prospectively. Ameren Missouri recognizes an offset to “Interest Charges” on its consolidated statement of income for its carrying cost of debt relating to each return allowed under the PISA, with the difference between the applicable WACC and its carrying cost of debt recognized in revenues when recovery of PISA deferrals is reflected in customer rates. Approved PISA deferrals are recovered over a period of 20 years following a regulatory rate review. Additionally, under the RESRAM, Ameren Missouri is permitted to recover the 15% of depreciation expense not recovered under the PISA, and earn a return at the applicable WACC for investments in renewable generation plant placed in service to comply with Missouri’s renewable energy standard. Accumulated RESRAM deferrals earn carrying costs at short-term interest rates. The PISA and the RESRAM mitigate the effects of regulatory lag between regulatory rate reviews. Those investments not eligible for recovery under the PISA and the remaining 15% of certain property, plant, and equipment placed in service, unless eligible for recovery under the RESRAM, remain subject to regulatory lag. Pursuant to a Missouri law that became effective in August 2022, Ameren Missouri’s PISA election was extended through 2028 and an additional extension through 2033 is allowed if requested by Ameren Missouri and approved by the MoPSC, among other things.

•In June 2023, the MoPSC issued an order that resulted in an increase of $140 million to Ameren Missouri’s annual revenue requirement for electric retail service. The order increased the annualized base level of net energy costs pursuant to the FAC by approximately $40 million from the base level established in the MoPSC’s December 2021 electric rate order. 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 approximate increases in “Depreciation and amortization” of $90 million and “Other income, net”, of $100 million, related to non-service pension and postretirement benefit income, on Ameren’s and Ameren Missouri’s consolidated statements of income. The new rates became effective on July 9, 2023. As a result of this order, Ameren Missouri expects a year-over-year increase to 2024 earnings, compared to 2023, of approximately $22 million ($11 million, $8 million, and $3 million expected in the first, second, and third quarter, respectively).

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•In 2018, the MoPSC issued an order approving Ameren Missouri’s MEEIA 2019 plan. The plan includes a portfolio of customer energy-efficiency and demand response programs through December 2024. Ameren Missouri intends to invest approximately $420 million over the life of the plan, including $76 million in 2024. The plan includes the continued use of the MEEIA rider, which allows Ameren Missouri to collect from, or refund to, customers any difference in actual MEEIA program costs and related lost electric margins and the amounts collected from customers. In addition, the plan includes a performance incentive that provides Ameren Missouri an opportunity to earn revenues by achieving certain customer energy-efficiency goals. If the target program spending goal is achieved for 2024, the performance incentive would result in revenues of $12 million in 2024.

•In January 2024, Ameren Missouri filed a proposed customer energy-efficiency plan with the MoPSC under the MEEIA. This filing proposed a three-year plan, which includes a portfolio of customer energy-efficiency programs, along with the continued use of the MEEIA rider discussed above. If the plan is approved, Ameren Missouri intends to invest $123 million annually in the proposed customer energy-efficiency programs from 2025 to 2027. In addition, Ameren Missouri requested performance incentives applicable to each plan year to earn revenues by achieving certain customer energy-efficiency savings and target spending goals. If 100% of the goals are achieved, Ameren Missouri would earn performance incentive revenues totaling $56 million over the three-year plan. Ameren Missouri also requested additional performance incentives applicable to each plan year totaling up to $14 million over the three-year plan, if Ameren Missouri exceeds 100% of the goals. Ameren Missouri expects a decision by the MoPSC by October 2024 but cannot predict the ultimate outcome of this regulatory proceeding.

•Ameren Illinois and ATXI use a forward-looking rate calculation with an annual revenue requirement reconciliation for each company’s electric transmission business. Based on expected rate base and the currently allowed 10.52% ROE, which includes a 50-basis-point incentive adder for participation in an RTO, the revenue requirements that will be included in 2024 rates for Ameren Illinois’ and ATXI’s electric transmission businesses are $549 million and $223 million, respectively. These revenue requirements represent increases in Ameren Illinois’ and ATXI’s revenue requirements of $73 million and $29 million, respectively, from the revenue requirements reflected in 2023 rates, primarily due to higher expected rate base. These rates will affect Ameren Illinois’ and ATXI’s cash receipts during 2024, but will not determine their respective electric transmission service operating revenues, which will instead be based on 2024 actual recoverable costs, rate base, and a return on rate base at the applicable WACC as calculated under the FERC formula ratemaking framework.

•The allowed base ROE for FERC-regulated transmission rates previously charged under the MISO tariff has been the subject of pending proceedings since 2013. Depending on the outcome of the proceedings, the transmission rates charged during previous periods and the currently effective rates may be subject to change and refund. In March 2020, the FERC issued a Notice of Proposed Rulemaking on its transmission incentives policy, which increased the incentive ROE for participation in an RTO to 100 basis points from the current 50 basis points and revised the parameters for awarding incentives, while limiting the overall incentives to a cap of 250 basis points, among other things. In April 2021, the FERC issued a Supplemental Notice of Proposed Rulemaking, which proposed to modify the Notice of Proposed Rulemaking’s incentive for participation in an RTO by limiting this incentive for utilities that join an RTO to 50 basis points and only allowing them to earn the incentive for three years, among other things. If this proposal is included in a final rule, Ameren Illinois and ATXI would no longer be eligible for the 50 basis point RTO incentive adder, prospectively. The FERC is under no deadline to issue a final rule on this matter. Ameren is unable to predict the ultimate impact of any changes to the FERC’s incentives policy, or any further order on base ROE. A 50-basis-point change in the FERC-allowed ROE would affect Ameren’s and Ameren Illinois’ annual net income by an estimated $16 million and $11 million, respectively, based on each company’s 2024 projected rate base.

•Pursuant to December 2022 and March 2021 ICC orders, Ameren Illinois used the IEIMA formula framework to establish annual electric distribution service rates effective through 2023, and will reconcile the related revenue requirement for customer rates established for 2023. As such, Ameren Illinois’ 2023 revenues reflected actual recoverable costs, year-end rate base, and a return at the applicable WACC, with the ROE component based on the annual average of the monthly yields of the 30-year United States Treasury bonds plus 580 basis points. By law, the decoupling provisions extend beyond 2023, which ensures that Ameren Illinois’ electric distribution revenues authorized in a regulatory rate review are not affected by changes in sales volumes. In November 2023, the ICC issued an order approving Ameren Illinois’ 2022 electric distribution service revenue requirement reconciliation adjustment filing. This order approved a reconciliation adjustment of $110 million. The approved reconciliation adjustment will be collected from customers in 2024. In addition, Ameren Illinois will file its 2023 electric distribution service revenue requirement reconciliation with the ICC by May 2024, which will reflect its 2023 year-end rate base. The 2023 reconciliation adjustment, if approved by the ICC, will be collected from customers in 2025.

•Pursuant to the CEJA, which was enacted in September 2021, Ameren Illinois may file an MYRP with the ICC to establish base rates for electric distribution service to be charged to customers for each calendar year of a four-year period. The base rates for a particular calendar year are based on forecasted recoverable costs and an ICC-determined ROE applied to Ameren Illinois’ forecasted average annual rate base using a forecasted capital structure, with a common equity ratio of up to 50% being deemed prudent and reasonable by law and a higher equity ratio requiring specific ICC approval. The ROE determined by the ICC for each calendar year of the four-year period is subject to annual adjustments based on certain performance incentives and penalties. An MYRP allows Ameren Illinois to

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reconcile electric distribution service rates to its actual revenue requirement on an annual basis, subject to a reconciliation cap and adjustments to the ROE. If a given year’s revenue amount collected from customers varies from the approved revenue requirement, an adjustment is made to electric operating revenues with an offset to a regulatory asset or liability to reflect that year’s actual revenue requirement, independent of actual sales volumes. The regulatory balance is then collected from, or refunded to, customers within two years from the end of the applicable annual period. Ameren Illinois’ existing riders will remain effective under the MYRP discussed below, and will continue to remain effective beyond 2027 whether it elects to file an MYRP or a traditional regulatory rate review. Additionally, electric distribution service revenues continue to be decoupled from sales volumes under either election.

•In December 2023, the ICC issued an order in Ameren Illinois' MYRP proceeding, approving revenue requirements for electric distribution service for 2024, 2025, 2026, and 2027 of $1,162 million, $1,210 million, $1,242 million, and $1,255 million, respectively. These revenue requirements were established under an alternative methodology which used Ameren Illinois’ previously approved 2022 year-end rate base since the order rejected the Grid Plan that was filed by Ameren Illinois as a part of the MYRP proceeding. The ICC concluded that the proposed Grid Plan did not meet certain statutory requirements and directed Ameren Illinois to file a revised Grid Plan within three months. Ameren Illinois expects to file a revised Grid Plan with the ICC in March 2024, and also expects to file a request to update the associated MYRP revenue requirements for 2024 through 2027 in the first half of 2024. The 2022 year-end rate base will remain in effect through 2027, unless subsequently changed by the ICC in the rehearing discussed below or if approval of a revised Grid Plan results in an update of each year’s revenue requirement. The approved revenue requirements in the ICC’s December 2023 order represent a cumulative increase of $142 million compared to a cumulative increase of $444 million requested by Ameren Illinois in its revised September 2023 MYRP filing. The ICC’s December 2023 order did not utilize a phase-in provision that is permitted by the CEJA for any initial rate increase. In January 2024, Ameren Illinois filed a request for rehearing of the ICC's December 2023 order. The filing contended that the use of the 2022 year-end rate base for each year of the MYRP, until a revised Grid Plan is approved, is unlawful and not in compliance with the CEJA. In addition, the filing requested the ICC revise the order to include an allowed ROE of at least 9.82% for each year of the MYRP and include a base level of investments to maintain grid reliability in each year of the MYRP, among other things. In January 2024, the ICC partially denied Ameren Illinois’ rehearing request by denying Ameren Illinois’ request regarding the allowed ROE, and granting Ameren Illinois’ request to consider whether it is appropriate to use the 2022 year-end rate base for each year of the MYRP and to include a base level of investments to maintain grid reliability in each year of the MYRP. Additionally, the scope of the rehearing will include a review of certain operations and maintenance expenses in each year of the MYRP. In February 2024, Ameren Illinois filed its request in the rehearing proceeding, which proposed updated revenue requirements of $1,214 million, $1,300 million, $1,371 million, and $1,420 million, for 2024, 2025, 2026, and 2027, respectively. An ICC decision in this rehearing is expected by late June 2024. Also, in January 2024, Ameren Illinois filed an appeal of the December 2023 ICC order and the partial denial of Ameren Illinois’ request for rehearing to the Illinois Appellate Court for the Fifth Judicial District. The court is under no deadline to address the appeal. Ameren Illinois cannot predict the ultimate outcome of the revised Grid Plan filing, its request to update the associated MYRP revenue requirements for 2024 through 2027, the rehearing proceeding, or the appeal to the Illinois Appellate Court for the Fifth Judicial District. Ameren Illinois intends to take prudent steps to align its 2024 operations with the ICC order, while continuing to ensure safe and adequate service is maintained. This will include significant reductions to Ameren Illinois’ capital expenditure and operations and maintenance expense plans.

•Pursuant to Illinois law, Ameren Illinois’ electric energy-efficiency investments are deferred as a regulatory asset and earn a return at the applicable WACC, with the ROE component based on the annual average of the monthly yields of the 30-year United States Treasury bonds plus 580 basis points. The allowed ROE on electric energy-efficiency investments can be increased or decreased by up to 200 basis points, depending on the achievement of annual energy savings goals. While the ICC has approved a plan for Ameren Illinois to invest approximately $120 million per year in electric energy-efficiency programs through 2025, the ICC has the ability to reduce the amount of electric energy-efficiency savings goals in future program years if there are insufficient cost-effective programs available, which could reduce the investments in electric energy-efficiency programs. The electric energy-efficiency program investments and the return on those investments are collected from customers through a rider.

•In November 2023, the ICC issued an order in Ameren Illinois’ January 2023 natural gas delivery service regulatory rate review, which resulted in an increase to its annual revenues for natural gas delivery service of $112 million. The new rates became effective on November 28, 2023. In December 2023, Ameren Illinois filed a request for rehearing with the ICC to revise the approved ROE and capital structure common equity percentage, and reverse an approximately $93 million reduction of planned distribution and transmission capital investments included in the order, among other things. In January 2024, the ICC denied Ameren Illinois’ rehearing request. Subsequently, in January 2024, Ameren Illinois filed an appeal of the November 2023 ICC order and the January 2024 ICC denial of Ameren Illinois’ request for rehearing to the Illinois Appellate Court for the Fifth Judicial District. The court is under no deadline to address the appeal. Ameren Illinois cannot predict the ultimate outcome of this appeal.

•The ICC’s November 2023 natural gas delivery service rate order also required Ameren Illinois to submit a plan outlining how it expects to comply with new PHMSA rules for natural gas transmission pipelines, including proposing a capital expenditures plan necessary to meet the new rules. In February 2024, Ameren Illinois filed its plan with the ICC, which included its proposal of natural gas transmission capital expenditures necessary to achieve compliance with the PHMSA rules. The plan includes delays to certain natural gas

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transmission capital expenditures from 2024 to subsequent years to align with the November 2023 ICC order. The ICC is under no obligation to issue an order regarding Ameren Illinois’ plan.

•The November 2023 order also directed the ICC staff to develop a plan for a future of gas proceeding. All of the Illinois natural gas utilities subject to ICC regulation will be included in this proceeding, which will explore issues involved with decarbonization of the natural gas distribution system in light of the state of Illinois’ goal of economy-wide 100% clean energy by 2050, pursuant to the CEJA. Some of the issues expected to be addressed include the mitigation of any natural gas distribution stranded assets, the role of energy efficiency in decarbonization, and the associated impacts of natural gas decarbonization to the electric distribution system, among others.

•Ameren Missouri’s next refueling and maintenance outage at its Callaway energy center is scheduled for the spring of 2025. During a scheduled refueling, which occurs every 18 months, maintenance expenses are deferred as a regulatory asset and amortized until the completion of the next refueling and maintenance outage. During an outage, depending on the availability of its other generation sources and the market prices for power, Ameren Missouri’s purchased power costs may increase and the amount of excess power available for sale may decrease versus non-outage years. Changes in purchased power costs and excess power available for sale are included in the FAC, which results in limited impacts to earnings. In addition, Ameren Missouri may incur increased non-nuclear energy center maintenance costs in non-outage years.

•In September 2023, the United States District Court for the Eastern District of Missouri granted Ameren Missouri’s request to modify a September 2019 remedy order issued by the district court in order to allow the retirement of the Rush Island Energy Center in advance of its previously expected useful life in lieu of installing a flue gas desulfurization system. In its amended remedy order, the district court established an October 15, 2024 retirement date and, in the interim, authorized Ameren Missouri to operate the energy center as directed by the MISO. The MISO designated the energy center as a system support resource in 2022 and concluded that certain reliability mitigation measures, including transmission upgrades, should occur before the energy center is retired. The Rush Island Energy Center began operating as a system support resource on September 1, 2022. In 2023, the MISO extended the system support resource designation through August 2024, and in September 2023, an agreement between Ameren Missouri and the MISO was approved by the FERC that results in the Rush Island Energy Center only operating during peak demand times and emergencies. The system support resource designation and the related agreement are subject to annual renewal and revision. Construction activities are underway for the transmission upgrades approved by the MISO, with the majority of the upgrades expected to be completed in the fall of 2024. Ameren Missouri expects to complete the last of the upgrades by mid-2025. For additional information on the NSR and Clean Air Act litigation, see Note 14 – Commitments and Contingencies under Part II, Item 8, of this report. As part of the assessment of any potential future abandonment loss, consideration will be given to rate and securitization orders issued by the MoPSC to Ameren Missouri and to orders issued to other Missouri utilities with similar facts. See below for information regarding Ameren Missouri’s petition filed with the MoPSC requesting the securitization of costs associated with the planned accelerated retirement of the Rush Island Energy Center.

•Pursuant to Illinois law, Ameren Missouri's natural gas-fired energy centers in Illinois are subject to annual limits on emissions, including CO2 and NOx. Further reductions to emissions limits will become effective between 2030 and 2040, resulting in the closure of the Venice Energy Center by the end of 2029. The reductions could also limit the operations of Ameren Missouri's four other natural gas-fired energy centers located in the state of Illinois, and will result in their closure by 2040. These energy centers are utilized to support peak loads. Subject to conditions in the CEJA, these energy centers may be allowed to exceed the emissions limits in order to maintain reliability of electric utility service.

•Ameren Missouri and Ameren Illinois continue to make infrastructure investments and expect to seek increases to electric and natural gas rates to recover the cost of investments and earn an adequate return. Ameren Missouri and Ameren Illinois will also seek new, or to maintain existing, regulatory and legislative solutions to address regulatory lag and to support investment in their utility infrastructure for the benefit of their customers. Ameren Missouri and Ameren Illinois continue to face cost recovery pressures, including limited economic growth in their service territories, increasing inflation, higher cost of debt, customer conservation efforts, the impacts of additional customer energy-efficiency programs, and increased customer use of increasingly cost-effective advancements in innovative energy technologies, including private generation and energy storage. However, we expect the decreased demand to be offset by increased demand resulting from increased electrification of the economy, including in the transportation sector, and as a means to address economy-wide CO2 emission concerns. We expect that increased investments, including expected future investments for environmental compliance, system reliability improvements, and new generation sources, will result in rate base and revenue growth but also higher depreciation and financing costs.

Liquidity and Capital Resources

•In September 2023, Ameren Missouri filed its 2023 IRP with the MoPSC, which includes Ameren Missouri’s preferred plan for meeting customers’ projected long-term energy needs in a manner that maintains system reliability and customer affordability while transitioning to clean energy generation in an environmentally responsible manner. In connection with this plan, Ameren is continuing to target net-zero carbon emissions by 2045, as well as a 60% reduction by 2030 and an 85% reduction by 2040 based on 2005 levels. Ameren’s

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goals include both direct emissions from operations (scope 1), as well as electricity usage at Ameren buildings (scope 2), including other greenhouse gas emissions of methane, nitrous oxide, and sulfur hexafluoride. Achieving these goals will be dependent on a variety of factors, including cost-effective advancements in innovative clean energy technologies and constructive federal and state energy and economic policies. The preferred plan includes, among other things, the following:

•adding an 800-MW natural gas-fired simple-cycle energy center by 2027 and an additional 1,200-MW natural gas-fired combined-cycle energy center by 2033;

•adding 2,800 MWs of renewable generation by 2030, which includes the solar generation facilities discussed below, and an additional 1,900 MWs by 2036;

•adding 400 MWs of battery storage by 2030 and an additional 400 MWs by 2035;

•adding 1,200 MWs of other clean dispatchable generation resources by 2040 and an additional 1,200 MWs by 2043;

•retiring all of Ameren Missouri’s coal-fired energy centers by 2042;

•accelerating the retirement date of the Rush Island coal-fired energy center from 2025 to 2024;

•extending the retirement date of the Sioux coal-fired energy center from 2030 to 2032 to ensure reliability during the transition to clean energy generation, which is subject to the approval of a change in depreciable lives of the energy center’s assets by the MoPSC;

•retiring 1,800 MWs of Ameren Missouri’s natural gas-fired energy centers by 2040 to comply with Illinois law;

•the continued implementation of customer energy-efficiency and demand response programs; and

•the expectation that Ameren Missouri will seek and receive NRC approval for an extension of the operating license for the Callaway Energy Center beyond its current 2044 expiration date.

Expected capital expenditures through 2028 related to the facilities discussed above are included in Ameren’s and Ameren Missouri’s expected capital investments discussed below. Ameren Missouri’s plan could be affected by, among other factors: Ameren Missouri’s ability to obtain CCNs from the MoPSC, and any other required approvals for the addition of renewable resources or natural gas-fired generation, retirement of energy centers, and new or continued customer energy-efficiency programs; the ability to enter into agreements for renewable or natural gas-fired generation and acquire or construct that generation at a reasonable cost; the ability of suppliers, contractors, and developers to meet contractual commitments and timely complete projects, which is dependent upon the availability of necessary labor, materials, and equipment, geopolitical conflict, or government actions, among other things; changes in the scope and timing of projects; the ability to qualify for, and use or transfer, federal production or investment tax credits; the cost of wind, solar, and other renewable generation and battery storage technologies; the cost of natural gas or hydrogen CT technologies; the ability to maintain system reliability during and after the transition to clean energy generation; new and/or changes in environmental regulations, including those related to CO2 and other greenhouse gas emissions; energy prices and demand; Ameren Missouri’s ability to obtain necessary rights-of-way, easements, and transmission interconnection agreements at an acceptable cost and in a timely fashion; the ability to earn an adequate return on invested capital; and the ability to raise capital on reasonable terms. The next integrated resource plan is expected to be filed in September 2026.

•Pursuant to Missouri law, in November 2023, Ameren Missouri petitioned the MoPSC for a financing order to authorize the issuance of securitized utility tariff bonds to finance $519 million of costs related to the planned accelerated retirement of the Rush Island Energy Center, which includes the expected remaining unrecovered net plant balance associated with the facility. Ameren Missouri requested to collect the amounts necessary to repay the bonds over approximately 15 years from the date of bond issuance. In February 2024, the MoPSC staff filed a response to Ameren Missouri’s petition that stated Ameren Missouri’s decision to accelerate the retirement of the Rush Island Energy Center was prudent and largely supported Ameren Missouri’s securitization request. However, the MoPSC staff claimed Ameren Missouri’s prior actions that resulted in the adverse ruling in the NSR and Clean Air Act Litigation discussed in Note 14 – Commitments and Contingencies under Part II, Item 8, of this report, were imprudent and recommended that the impact of those actions on customers be considered in future rate reviews. If Ameren Missouri is not allowed to recover Rush Island Energy Center costs through securitization or if future rate reviews result in revenue reductions based on Ameren Missouri’s prior actions that resulted in the adverse ruling in the NSR and Clean Air Act Litigation, it could have a material adverse effect on the results of operations, financial position, and liquidity of Ameren and Ameren Missouri. Ameren Missouri expects a decision by the MoPSC by the end of June 2024, but cannot predict the ultimate outcome of this regulatory proceeding.

•During 2022 and 2023, Ameren Missouri, and certain subsidiaries of Ameren Missouri, entered into agreements to acquire and/or construct various solar generation facilities, with various regulatory approvals pending. All of the solar generation facilities are aligned with the 2023 IRP discussed above, and expected capital expenditures related to these facilities are included in Ameren’s and Ameren Missouri’s expected capital investments discussed below.

•Ameren Missouri's 2023 IRP targets cleaner and more diverse sources of energy generation, including solar generation. While rights to acquire build-transfer solar facilities and supplies for development-transfer and self-build solar facilities discussed above were secured through agreements, supply chain disruptions, including solar panel shortages and increasing material costs as a result of government tariffs and other factors, could affect the costs, as well as the timing, of these projects and other solar generation projects. The supply of

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solar panel components to the United States was significantly disrupted as a result of an investigation conducted by the United States Department of Commerce that concluded in August 2023 and found that exporters and producers of solar panel components from four Southeast Asian countries, with several exceptions, have been circumventing tariffs imposed on imports from China. As a result of the investigation, importers and exporters may submit certain certifications to the United States Department of Commerce to avoid the imposition of increased tariffs. Failure to submit the applicable certifications, or denial of the submitted certifications by the United States Department of Commerce, could result in increased tariffs on solar panel components that were subject to the investigation and entered the United States on or after April 1, 2022. Additionally, certain solar panel components from China have been subject to detention by the United States Customs and Border Protection Agency as a result of the Uyghur Forced Labor Prevention Act that became effective in June 2022. Also, in June 2022, President Biden took executive action to temporarily lift certain tariffs on solar panel components imported from the four Southeast Asian countries investigated by the United States Department of Commerce for 24 months in order to allow the United States access to a sufficient supply of solar panel components. Any future tariffs or actions by the United States Customs and Border Protection Agency could affect the cost and the availability of solar panel components and the timing and amount of Ameren Missouri's estimated capital expenditures associated with solar generation investments.

•Through 2028, we expect to make significant capital expenditures to improve our electric and natural gas utility infrastructure, with a major portion directed to our transmission and distribution systems. We estimate that we will invest up to $22.8 billion (Ameren Missouri – up to $13.5 billion; Ameren Illinois – up to $7.6 billion; ATXI – up to $1.7 billion) of capital expenditures during the period from 2024 through 2028. Ameren’s and Ameren Missouri’s estimates include $3.3 billion of renewable generation investments and $2.7 billion of dispatchable generation investments through 2028, consistent with Ameren Missouri’s 2023 IRP. Ameren’s and Ameren Illinois’ estimates include investments necessary to meet compliance requirements of the CEJA, while continuing to ensure safe and adequate service is maintained. Ameren Illinois’ estimates may be revised as a result of future ICC orders related to its MYRP.

•In 2021, the MISO issued a report outlining a preliminary long-range transmission planning roadmap of projects through 2039, which considers the rapidly changing generation mix within MISO resulting from significant additions of renewable generation, actual and expected generation plant closures, and state mandates or goals for clean energy or carbon emissions reductions. In July 2022, the MISO approved the first tranche of projects under the first phase of the roadmap. A portion of these projects were assigned to various utilities, of which Ameren was awarded projects that are estimated to cost approximately $1.8 billion, based on the MISO’s cost estimate. Related to these projects, Ameren expects to begin substation upgrades in 2024 in advance of transmission line construction, which is expected to begin in 2026, with forecasted completion dates near the end of this decade. In October 2023, the FERC issued an order that approved transmission rate incentives relating to the projects assigned to Ameren. The incentives will allow construction work in progress to be included in rate base for projects constructed by ATXI, thereby improving the timeliness of cash recovery, and would allow recovery of prudently incurred costs, subject to FERC approval, for any portion of the projects if they are abandoned for reasons beyond the control of Ameren. As a result of the order, ATXI will not capitalize allowance for funds used during construction on the related projects. In 2022 and 2023, the MISO initiated requests for proposals for first tranche competitive bid projects. In October and November 2023, first tranche competitive bid projects were awarded to ATXI and represent a total estimated investment of approximately $0.1 billion. The remaining competitive-bid project is estimated by the MISO to cost approximately $0.6 billion and is expected to be awarded by mid-2024. In February 2024, Ameren Illinois and ATXI filed a request for a CCN with the ICC related to the portion of the MISO long-range transmission projects discussed above that are expected to be constructed within the ICC’s jurisdiction. A decision by the ICC is expected by February 2025. In November 2022, the MISO released plans for a second tranche of projects and began the process of identifying a list of projects for consideration under this tranche. Ameren expects the second tranche of projects to be approved in the first half of 2024. In July 2022, a group of industrial customers filed a complaint with the FERC, challenging provisions of a MISO tariff that exclude regional transmission projects from the MISO’s competitive bid process based on state laws related to the right of first refusal, which provide an incumbent utility the right to build, maintain, and own transmission lines located within its service territory. The complaint seeks to require MISO to revise its tariff to prohibit the application of state laws related to the right of first refusal in the MISO’s long-range transmission planning and require projects to be bid on a competitive basis, to the maximum extent possible. It also is asking for refunds related to any costs under the tariff that would not comply with the sought-after revisions. The FERC is under no deadline to issue an order in this proceeding.

•In July 2022, an Illinois law prohibiting the state’s oversight of certain electric utilities’ choice of RTO membership ceased to be effective. Given the change in law and the high prices resulting from the MISO’s April 2022 capacity auction, the ICC issued an order requiring Ameren Illinois to perform a cost-benefit study of continued participation in the MISO compared to participation in PJM Interconnection LLC, another RTO. In July 2023, Ameren Illinois filed its cost-benefit study with the ICC. The cost-benefit study examined the impacts of participation in each RTO, including reliability, resiliency, affordability, and environmental impacts, among other things, for a period of five to 10 years beginning June 2024. The study concluded that continued participation in the MISO was prudent and more cost-beneficial than participation in PJM Interconnection LLC. In January 2024, the ICC staff submitted a report recommending the ICC not take any action with regard to changing Ameren Illinois’ RTO membership. The ICC is under no obligation to issue an order related to the cost-benefit study.

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•Environmental regulations, including those related to CO2 emissions, or other actions taken by the EPA or state regulators, or requirements that may result from the NSR and Clean Air Act Litigation, could result in significant increases in capital expenditures and operating costs. Regulations can be reviewed and repealed, and replacement or alternative regulations can be proposed or adopted by the current federal administration, including the EPA. See Note 14 – Commitments and Contingencies under Part II, Item 8, of this report, for additional information on environmental matters, including the NSR and Clean Air Act litigation. The ultimate implementation of any of these new regulations, as well as the timing of any such implementation, is uncertain. However, the individual or combined effects of existing and new environmental regulations could result in significant capital expenditures, increased operating costs, or the closure or alteration of some of Ameren Missouri’s coal and natural gas-fired energy centers. Ameren Missouri’s capital expenditures are subject to MoPSC prudence reviews, which could result in cost disallowances, as well as regulatory lag. The cost of Ameren Illinois’ purchased power and natural gas purchased for resale could increase. However, Ameren Illinois expects that these costs would be recovered from customers with no material adverse effect on its results of operations, financial position, or liquidity. Ameren’s and Ameren Missouri’s earnings could benefit from increased investment to comply with environmental regulations if those investments are reflected and recovered on a timely basis in customer rates.

•The Ameren Companies have multiyear credit agreements that cumulatively provide $2.6 billion of credit through December 2027, subject to a 364-day repayment term for Ameren Missouri and Ameren Illinois, with the option to seek incremental commitments to increase the cumulative credit provided to $3.2 billion. See Note 4 – Short-term Debt and Liquidity under Part II, Item 8, of this report for additional information regarding the Credit Agreements. See Note 5 – Long-term Debt and Equity Financings under Part II, Item 8, of this report for outstanding forward sale agreements under the ATM, long-term debt issuances through the date of this report, and maturities of long-term debt from 2024 to 2028 and beyond at Ameren (parent), Ameren Missouri, Ameren Illinois, and ATXI. The use of cash provided by operating activities and short-term borrowings to fund capital expenditures and other long-term investments at the Ameren Companies frequently results in a working capital deficit, defined as current liabilities exceeding current assets, as was the case at December 31, 2023, for Ameren, Ameren Missouri, and Ameren Illinois. Ameren, Ameren Missouri, and Ameren Illinois each believe that their liquidity is adequate given their respective expected operating cash flows, capital expenditures, and financing plans, and expect to continue to have access to the capital and credit markets on reasonable terms when needed. However, there can be no assurance that significant changes in economic conditions, disruptions in the capital and credit markets, or other unforeseen events will not materially affect their ability to execute their expected operating, capital, or financing plans.

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AEE · 10-K · period ended 2023-12-31

ITEM 7.MANAGEMENT’S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS

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AEE · 10-K · period ended 2023-12-31

ITEM 7.MANAGEMENT’S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS

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