What changed in this filing

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Item 7. Management’s Discussion and Analysis

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We believe this per share information helps readers to understand the impact of these factors on Ameren’s earnings per diluted share.

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:

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

Investing in rate-regulated energy infrastructure Enhancing regulatory frameworks and advocating for responsible policies Optimizing operating performance

To capitalize on opportunities to benefit our customers, communities, shareholders, and the environment

To deliver on opportunities to benefit our customers, communities, and shareholders

We invest in rate-regulated energy infrastructure and seek to earn competitive returns on our investments.

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Regulatory Frameworks (c)

Electric Customer Rates (f)

Electric Customer Rates (g)

Segment Regulatory Framework

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Allowed ROE of 9.60%

Missouri Historical test year ratemaking and

Missouri Historical test year ratemaking (f) and

PISA, RESRAM, FAC, MEEIA, PGA

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(d) Ameren Illinois filed appeals of the December 2023 and June 2024 orders, and intends to file an appeal of the December 2024 ICC order, in its MYRP proceeding.

(d) Ameren Illinois filed appeals of the December 2023, June 2024, and December 2024 orders in its MYRP proceeding.

For more information on the MYRP proceeding, see Note 2 – Rate and Regulatory Matters under Part II, Item 8, of this report.

(e) Ameren Illinois’ formula ratemaking framework related to energy-efficiency investments uses an allowed ROE of the annual average of the monthly yields of the 30-year United States Treasury bonds plus 580 basis points, subject to performance standards discussed in Note 2 – Rate and Regulatory Matters under Part II, Item 8, of this report.

(f) Average residential electric prices.

(e) Through 2026, Ameren Illinois’ formula ratemaking framework related to energy-efficiency investments uses an allowed ROE of the annual average of the monthly yields of the 30-year United States Treasury bonds plus 580 basis points, subject to performance standards discussed in Note 2 – Rate and Regulatory Matters under Part II, Item 8, of this report.

(f) Pursuant to the PPRA, Ameren Missouri will be allowed to use a future test year, subject to MoPSC approval, to set natural gas delivery service rates beginning in July 2026.

For more information on the PPRA, see Note 2 – Rate and Regulatory Matters under Part II, Item 8, of this report.

(g) Average residential electric prices in cents per kilowatthour.

Edison Electric Institute, ‘Typical Bills and Average Rates Report’ for the 12 months ended June 30, 2025.

Key announcements, updates, and regulatory outcomes

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 retirement date of 2039, in lieu of installing a flue gas desulfurization system.

Ameren Missouri retired the Rush Island Energy Center on October 15, 2024.

In December 2024, the United States District Court for the Eastern District of Missouri issued an order resolving all outstanding claims in this case.

The order requires Ameren Missouri to fund a program to provide electric buses and charging stations to schools in the metro St.

Louis area and a program to provide air purifiers to eligible Ameren Missouri electric residential customers.

These programs are estimated to cost approximately $64 million.

As of December 31, 2024, Ameren and Ameren Missouri recorded liabilities of $64 million and charges of $59 million in 2024 related to the cost of these programs.

In June 2024, Ameren Missouri filed a request with the MoPSC seeking approval to increase its annual revenues for electric service.

In February 2025, Ameren Missouri filed an updated electric rate increase request seeking approval to increase its annual revenues for electric service by $446 million .

The electric rate increase request is based on a 10.25% ROE, a capital structure composed of 52% common equity, a rate base of $13.9 billion, and a test year ended March 31, 2024, with certain pro-forma adjustments through the true-up date of December 31, 2024.

In February 2025, the MoPSC staff recommended an increase to Ameren Missouri's annual electric service revenues of $384 million based on a 9.74% ROE, a capital structure composed of 52% common equity, and a rate base of $13.9 billion.

The MoPSC proceeding relating to the proposed electric service rate changes will take place over a period of up to 11 months, with a decision by the MoPSC expected by May 2025 and new rates effective by June 2025.

In June 2024, the MoPSC issued a financing order authorizing the issuance of securitized utility tariff bonds by AMF to finance $476 million of costs related to the accelerated retirement of the Rush Island Energy Center, which included the remaining unrecovered net plant balance associated with the facility, among other costs.

Ameren Missouri will collect the amounts necessary to repay the bonds over approximately 15 years from the date of bond issuance.

The securitized tariff bonds were issued in December 2024.

The financing order also included a determination that the decision to retire the Rush Island Energy Center was reasonable and prudent.

The MoPSC did not make a determination regarding the prudency of 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, however, claims regarding such actions could be considered in future regulatory proceedings.

If future regulatory proceedings 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.

In 2024, the MoPSC issued orders approving requested CCNs for the Split Rail, Vandalia, Bowling Green, and Cass County solar projects .

Ameren Missouri acquired the Cass County, Boomtown, and Huck Finn solar projects in June 2024, September 2024, and October 2024, respectively, and placed the assets of the projects, totaling $1 billion, in service in December 2024.

In October 2024, the MoPSC issued an order approving a nonunanimous stipulation and agreement filed by Ameren Missouri, the MoPSC staff, and other intervenors requesting a CCN for the Castle Bluff Natural Gas Project.

The order also includes the use of a post-construction cost deferral related to the project, which allows Ameren Missouri to defer and recover depreciation expense, financing costs, and applicable income taxes incurred from the date the project is placed in service to the date when project costs are reflected in updated base rates as a result of a regulatory rate review.

The period of deferral would be limited to the earlier of the time the project costs are reflected in base rates or six months.

In September 2024, Ameren Missouri filed a request with the MoPSC seeking approval to increase its annual revenues for natural gas delivery service by $40 million.

The natural gas rate increase request is based on a 10.25% ROE, a capital structure composed of 52% common equity, a rate base of $531 million, and a test year ended March 31, 2024, with certain pro-forma adjustments expected through the true-up date of December 31, 2024.

The MoPSC proceeding relating to the proposed natural gas delivery service rate changes will take place over a period of up to 11 months, with a decision by the MoPSC expected by August 2025 and new rates effective by September 2025.

In November 2024, the MoPSC issued an order approving a nonunanimous stipulation and agreement for Ameren Missouri’s MEEIA 2025 plan, which includes a portfolio of customer energy-efficiency and demand response programs, along with the continued use of the MEEIA rider, which allows Ameren Missouri to collect from customers its actual MEEIA program costs, related lost electric revenues, and performance incentives.

Ameren Missouri intends to invest $51 million annually in 2025 and 2026 and $22 million in 2027 for customer energy-efficiency and demand response programs.

In addition, the order approved performance incentives applicable to each plan year to earn revenues by achieving certain spending and demand response goals.

If 100% of the goals are achieved in 2025, 2026, and 2027, Ameren Missouri would earn performance incentive revenues of $5 million, $5 million, and $2 million, respectively.

The PPRA became effective in August 2025.

The law includes certain provisions that affect the regulation of Ameren Missouri’s electric and natural gas businesses.

These provisions create modifications to the PISA and integrated resource planning, require electric utilities to submit service tariff schedules for certain large load customers, allow the MoPSC to authorize inclusion of construction work in progress in rate base for new natural gas-fired generation facilities and new generation facilities approved through integrated resource planning, and allow natural gas utilities to file regulatory rate reviews using a future test year, among other things.

In April 2025, the MoPSC issued an order in Ameren Missouri’s 2024 electric service regulatory rate review, approving nonunanimous stipulations and agreements.

The order authorized an increase of $355 million to Ameren Missouri’s annual revenue requirement for electric retail service, effective June 1, 2025.

The approved revenue requirement was based on infrastructure investments as of December 31, 2024.

The order did not explicitly specify an ROE, capital structure, rate base, or any rate base disallowances.

The order provides for the continued use of all existing riders and trackers.

The order also changed annualized depreciation, regulatory asset and liability amortization amounts, and the base level of expenses for trackers.

On an annualized basis, these changes reflect an increase in “Depreciation and amortization” of approximately $70 million, among other expense changes, on Ameren’s and Ameren Missouri’s consolidated statements of income.

In July 2025, the MoPSC issued an order in Ameren Missouri’s 2024 natural gas delivery service regulatory rate review, approving a unanimous stipulation and agreement.

The order authorized an increase of $32 million to Ameren Missouri’s annual revenue requirement for natural gas delivery service, effective September 1, 2025.

The order did not explicitly specify an ROE, capital structure, rate base, or any rate base disallowances.

The order provides for the continued use of all of Ameren Missouri’s existing riders and trackers.

In November 2025, the MoPSC approved Ameren Missouri’s request to modify its existing large primary service tariff to require customers requesting 75 MWs or more of demand and who are served at transmission level voltage to comply with additional tariff terms.

The additional terms include a service term of 12 years plus a ramp period of up to five years to reach peak demand, minimum demand charges of 80% of contracted capacity, customer exit terms and fees, and customer credit and collateral requirements, among other terms.

In addition, new customer programs would be available under this tariff, which allow customers to support renewable generation, battery storage, and/or nuclear generation through incremental payments.

The MoPSC order also includes an earnings sharing mechanism that would apply if Ameren Missouri’s earned ROE for a calendar year exceeds 9.74%, which can be adjusted by the MoPSC in future electric rate orders.

If this were to occur, Ameren Missouri would defer 65% of the return in excess of the 9.74% ROE to a regulatory liability, which would be returned to retail electric customers in a future rate review.

In addition, if large load customer revenues were reduced in a calendar year due to certain events, as determined by the MoPSC, Ameren Missouri may defer a portion of the reduced revenues to a regulatory asset to be included in its revenue requirement in the next electric rate review.

In February 2026, Ameren Missouri executed electric service agreements with large load customers consistent with the tariff terms discussed above, representing 2.2 gigawatts of demand.

Ameren and Ameren Missouri do not expect a material impact to their results of operations, financial position, or liquidity in 2026 related to these agreements.

In August 2025, Ameren Missouri filed for a CCN to construct the Reform Solar Project (250-MW facility).

Ameren Missouri expects a decision by the MoPSC in the first half of 2026.

In February 2026, the MoPSC issued an order approving a nonunanimous stipulation and agreement related to a requested CCN for the Big Hollow Natural Gas (800-MW facility) and the Big Hollow Battery Energy Storage (400-MW facility) projects.

Also in February 2026, Ameren Missouri acquired the Split Rail Solar Project, which includes solar panels, project design, land rights, and engineering, procurement, and construction agreements, for approximately $600 million, and took over construction management of the project, which is expected to be placed in-service in the second quarter of 2026.

In February 2026, 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 2026.

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Investments under the plan are expected to total approximately $20.8 billion over the five-year period from 2026 through 2030, with expenditures largely recoverable under the PISA.

Ameren Missouri’s Smart Energy Plan includes approximately $1 billion in capital expenditures that may be necessary to comply with regulations issued by the EPA in 2024 relating to CO 2 emissions and MATS, if such regulations are not revised or overturned.

See Note 14 – Commitments and Contingencies under Part II, Item 8, of this report, for additional information on the EPA regulations.

The Smart Energy Plan excludes investments in its natural gas distribution business, as well as removal costs, net of salvage.

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, and Ameren Illinois filed an appeal with the Illinois Appellate Court for the Fifth Judicial District.

In January 2025, the appellate court ruled on the appeal filed by Ameren Illinois.

In that ruling, the court reversed a reduction of planned transmission capital investments of $48 million, but affirmed the ICC-approved 9.44% ROE and the remaining reduction of planned distribution capital investments.

Ameren Illinois took prudent steps to align its operations with the ICC order, while continuing to ensure safe and adequate service is maintained.

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 December 2023 order became effective in January 2024 and remained effective through late June 2024, when new rates became effective pursuant to the June 2024 ICC rehearing order discussed below.

The December 2023 order adopted an alternative methodology to establish a rate base and revenue requirements for the years 2024 through 2027 using Ameren Illinois’ previously approved 2022 year-end rate base.

In January 2024, the ICC partially denied a rehearing requested by Ameren Illinois to revise the allowed ROE in the December 2023 order and granted Ameren Illinois’ rehearing request to reconsider the 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.

In June 2024, the ICC issued an order on Ameren Illinois’ rehearing request approving revenue requirements for electric distribution services for 2024 through 2027.

New rates became effective in late June 2024 and remained effective through late December 2024, when new rates became effective pursuant to the December 2024 ICC order discussed below.

In July 2024, Ameren Illinois filed a request for rehearing of the ICC’s June 2024 rehearing order to include an asset associated with other postretirement benefits in the rate base.

Subsequently, in August 2024, the ICC denied the rehearing request.

Also, in January 2024, Ameren Illinois filed an appeal of the December 2023 ICC order, including the 8.72% ROE, and subsequently updated the appeal filing in September 2024 to include the June 2024 rehearing order regarding the inclusion of an asset associated with other postretirement benefits in the rate base to the Illinois Appellate Court for the Fifth Judicial District.

The court is under no deadline to address the appeal and Ameren Illinois cannot predict the ultimate outcome of the appeal.

In March 2024, pursuant to the December 2023 ICC order discussed above, Ameren Illinois filed a revised Grid Plan and a revised MYRP to update the requested revenue requirements for 2024 through 2027.

In December 2024, the ICC issued an order in connection with Ameren Illinois’ revised Grid Plan and revised MYRP, approving revenue requirements for electric distribution services for 2024, 2025, 2026, and 2027 of $1,206 million, $1,287 million, $1,367 million, and $1,422 million, respectively.

In December 2024, the ICC issued an order in connection with a revised Grid Plan and a revised MYRP filed by Ameren Illinois in March 2024, approving revenue requirements for electric distribution services for 2024 through 2027 of $1,206 million, $1,287 million, $1,367 million, and $1,421 million, respectively.

Rate changes consistent with the December 2024 order became effective in December 2024.

In January 2025, Ameren Illinois filed a request for rehearing of the ICC’s December 2024 order to revise the allowed ROE and to include an asset associated with other postretirement benefits in the rate base, among other things.

Subsequently, in February 2025, the ICC denied the rehearing request.

Ameren Illinois intends to file an appeal of the ICC’s December 2024 order and update the appeal filed in September 2024 to the Illinois Appellate Court for the Fifth Judicial District as discussed above.

In 20 24, Ameren Illinois took prudent steps to align its operations with the December 2023 and June 2024 ICC orders, while continuing to ensure safe and adequate service was maintained.

In November 2024, the ICC issued an order in Ameren Illinois’ annual update filing that approved electric customer energy-efficiency rates of $126 million beginning in January 2025, which represents an increase of $26 million from 2024 rates.

This order was based on a projected 2025 year-end rate base of $434 million.

In March 2025, Ameren Illinois filed an appeal of the ICC’s December 2024 order to the Illinois Appellate Court for the Fifth Judicial District to revise the allowed ROE and to include an asset associated with other postretirement benefits in the rate base, among other things.

In addition, Ameren Illinois filed an appeal related to orders issued by the ICC in December 2023 and June 2024 related to the MYRP proceeding.

The appellate court is under no deadline to address the appeals.

In December 2025, the ICC issued an order approving Ameren Illinois’ 2024 electric distribution service revenue requirement reconciliation adjustment filing.

This order approved a reconciliation adjustment of $158 million, which reflected Ameren Illinois’ actual 2023 recoverable costs, year-end rate base of $4.2 billion, and capital structure composed of 50% common equity.

This order approved an adjustment increasing the allowed revenue requirement by $48 million, which reflected Ameren Illinois’ actual 2024 recoverable costs, year-end rate base of $4.2 billion, and capital structure composed of 50% common equity.

The approved reconciliation adjustment will be collected from customers in 2026.

In January 2025, Ameren Illinois filed a request with the ICC seeking approval to increase its annual revenues for natural gas delivery service by $140 million.

The request is based on a 10.7% ROE, a capital structure composed of 52% common equity, and a rate base of $3.3

Ameren Illinois used a 2026 future test year in this proceeding.

A decision by the ICC in this proceeding is required by early December 2025, with new rates expected to be effective in December 2025.

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 2022, the MISO approved the first tranche of projects under 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 began substation upgrades in May 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 addition, the MISO awarded three competitive bid projects to ATXI that represent a total estimated investment of approximately $220 million for ATXI.

In February 2024, Ameren Illinois and ATXI filed a request for a CCN, among other things, with the ICC related to the portion of the MISO long-range transmission projects they will construct within the ICC’s jurisdiction.

A decision by the ICC is expected by mid-2025.

In 2024, ATXI filed requests for CCNs, among other things, with the MoPSC related to the MISO long-range transmission projects that it expects to construct within the MoPSC’s jurisdiction.

Decisions by the MoPSC are expected in 2025.

Also in December 2024, the MISO approved a first set of second tranche projects.

A portion of these projects were assigned to Ameren and are estimated to cost approximately $1.3 billion, based on the MISO’s cost estimate.

The first set of second tranche projects also includes competitive bid projects that are estimated to cost $6.5 billion, which includes projects located in Illinois that are estimated to cost $1.8 billion, based on the MISO’s cost estimate.

The competitive bid process is expected to take place through 2026.

The MISO is assessing future long-range transmission scenarios in the first quarter of 2025 and development of a second set of second tranche projects will follow this assessment.

In October 2024, the FERC issued an order, which decreased the allowed base ROE for FERC-regulated transmission rate base under the MISO tariff from 10.02% to 9.98% and required refunds, with interest, for the periods from November 2013 to February 2015 and from late September 2016 forward.

In November 2024, the MISO transmission owners, including Ameren Missouri, Ameren Illinois, and ATXI, filed a request for rehearing with the FERC, arguing, among other things, the FERC should not have ordered refunds back to September 2016 or imposed interest on those refunds.

Also in November 2024, another intervenor filed a request for rehearing with the FERC, requesting the FERC correct aspects of the ROE methodology used in the October 2024 order and reconsider its decision in a February 2015 complaint case to deny refunds for the period from February 2015 to May 2016.

In December 2024, the FERC issued a notice indicating a future order related to the rehearing requests will be issued but did not specify a timeline.

In January 2025, the MISO transmission owners, including Ameren Missouri, Ameren Illinois, and ATXI, filed an appeal of the October 2024 order to the United States Court of Appeals for the District of Columbia Circuit.

As a result of the October 2024 order, Ameren and Ameren Illinois recognized reductions to electric revenues of $10 million and $7 million, respectively, and recognized interest expense of $2 million and $1 million, respectively, on their statements of income in 2024.

In February 2026, the ICC denied Ameren Illinois’ rehearing request to include an asset associated with other postretirement benefits in the rate base, among other things.

Ameren Illinois is assessing whether to pursue an appeal with the Illinois Appellate Court for the Fifth Judicial District in the first half of 2026.

In November 2025, the ICC issued an order in Ameren Illinois’ annual update filing that approved an electric customer energy-efficiency revenue requirement of $138 million beginning in January 2026, which represents an increase of $12 million from the 2025 revenue requirement.

This order was based on a projected 2026 year-end rate base of $474 million .

In August 2025, the ICC issued an order approving Ameren Illinois’ energy-efficiency plan that includes annual investments in electric energy-efficiency programs of approximately $126 million per year from 2026 through 2029.

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.

In January 2026, the CRGA was enacted and will become effective in June 2026.

The law includes certain provisions that affect Ameren Illinois’ electric distribution and transmission businesses.

These provisions increase the annual spending cap on energy-efficiency investments beginning in 2027 and modify the ROE component of the return on those investments.

In November 2025, the ICC issued an order in Ameren Illinois’ January 2025 natural gas delivery service regulatory rate review, which resulted in an increase to its annual revenues for natural gas delivery service of $79 million based on a 9.60% ROE, a capital structure composed of 50% common equity, a 2026 future test year, and a rate base of $3.2 billion.

The order reflected a reduction of $75 million of planned distribution and transmission capital investments included in Ameren Illinois’ future test year request.

The new rates became effective December 2025.

In January 2026, Ameren Illinois filed an appeal of the ICC’s November 2025 order and the ICC’s January 2026 order rejecting Ameren Illinois’ rehearing request to the Illinois Appellate Court for the Fifth Judicial District.

The appeal challenged the inclusion of the non-service cost component of the net periodic benefit income related to other postretirement benefits in the annual revenue requirement and the $75 million reduction of planned capital investments, among other things.

The court is under no deadline to address the appeal .

In February 2025, Ameren’s board of directors increased the quarterly common stock dividend to 71 cents per share, resulting in an annualized equivalent dividend rate of $2.84 per share.

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Net income attributable to Ameren common shareholders was $1,456 million, or $5.35 per diluted share, for 2025, and $1,182 million, or $4.42 per diluted share, for 2024.

Net income was favorably affected in 2024, compared with 2023, by increased infrastructure investments at Ameren Transmission and Ameren Missouri.

Net income was also favorably affected in 2024, compared with 2023, by increased base rate revenues pursuant to the MoPSC's June 2023 electric rate order as well as higher base rate revenues pursuant to the ICC's November 2023 natural gas rate order, which increased earnings at Ameren Illinois Natural Gas.

Additionally, earnings in 2024, compared with 2023, were favorably affected by decreased other operations and maintenance expenses not subject to formula rates, riders, or trackers, largely because of lower energy center maintenance costs, lower storm costs, disciplined cost management including lower labor costs from decreased headcount and decreased use of contractors, and lower amortization of refueling costs for the Callaway Energy Center, partially offset by the absence of the regulatory deferrals associated with the June 2023 MoPSC rate order.

Net income in 2024, compared with 2023, was also favorably affected by increased retail electric sales volumes at Ameren Missouri, primarily due to higher sales excluding customer energy-efficiency programs.

Net income was unfavorably affected in 2024, compared with 2023, by two charges related to matters that originated over a decade ago.

The first of these charges was recorded by Ameren Missouri related to an order from the United States District Court for the Eastern District of Missouri, which resolved all outstanding claims in the NSR and Clean Air Ac t litigation related to the Rush Island Energy Center.

The second charge was recognized by Ameren Illinois and ATXI for the decrease in the allowed base ROE under the MISO tariff resulting from the October 2024 FERC order, which included customer refunds for certain historical periods.

Net income in 2024, compared with 2023, was also unfavorably affected by increased financing costs due to higher long-term debt balances and interest rates at Ameren Missouri and Ameren (parent), a lower recognized ROE under the MYRP, and an increase in the weighted-average basic common shares outstanding, which reduced earnings per diluted share.

Net income was favorably affected in 2025, compared with 2024, by increased base rate revenues at Ameren Missouri effective June 1, 2025, pursuant to the April 2025 MoPSC electric rate order and decreased tax expense at Ameren Transmission, Ameren Illinois Electric Distribution and Ameren Illinois Natural Gas due to the revaluation of excess deferred income tax regulatory liabilities.

Earnings were also favorably affected by increased retail electric sales volumes at Ameren Missouri, primarily due to warmer July temperatures and colder winter temperatures in 2025, and by decreased other operations and maintenance expenses not subject to formula rates, riders, or trackers, because of the absence in 2025 of an Ameren Missouri charge related to the resolution of outstanding claims in the NSR and Clean Air Act litigation associated with the Rush Island Energy Center.

Additionally, earnings were favorably affected by the increased deferral of financing costs related to rate base investments at Ameren Missouri and by increased infrastructure investments at Ameren Transmission and Ameren Illinois Electric Distribution.

Net income was unfavorably affected in 2025 compared with 2024 by increased financing costs, primarily resulting from higher interest rates on higher debt balances at Ameren Missouri and Ameren (parent) and by increased other operations and maintenance expenses not subject to formula rates, riders, or trackers, excluding a charge related to the NSR and Clean Air Act litigation, primarily due to higher vegetation management costs, higher storm costs, and higher energy center maintenance expenses.

Additionally, earnings were unfavorably affected by an increase in the weighted-average basic common shares outstanding, which reduced earnings per diluted share.

At December 31, 2025, Ameren, on a consolidated basis, had available liquidity in the form of cash on hand and amounts available under the Credit Agreements of $2.5 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, 2024, Ameren had approximately $550 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, 2024.

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.

Ameren may offer and sell from time to time common stock, including under its ATM program, which includes the ability to enter into forward sale agreements, subject to market conditions and other factors.

As of December 31, 2025, Ameren had approximately $1.5 billion of common stock remaining available for sale under the ATM program.

As of December 31, 2025, Ameren had multiple forward sale agreements with various counterparties relating to 6.4 million shares of common stock, which it expects to settle in 2026.

For information regarding long-term debt issuances and maturities, common stock issuances, and outstanding forward sale agreements, including those 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.

Ameren remains focused on strategic capital allocation.

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(a) Amounts include investments under Ameren Missouri’s Smart Energy Plan.

(b) Amounts include the MISO long-range transmission projects assigned to Ameren, as well as the first tranche competitive projects awarded to ATXI discussed above .

(b) Amounts include the MISO long-range transmission projects assigned to Ameren, as well as the first tranche competitive projects awarded to ATXI .

RESULTS OF OPERATIONS

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Net income attributable to Ameren common shareholders in 2025 increased $274 million, and $0.93 per diluted share, from 2024.

The increase was due to net income increases of $27 million, $15 million, and $14 million at Ameren Transmission, Ameren Illinois Natural Gas, and Ameren Missouri, respectively.

The increases in net income were partially offset by a net income decrease of $24 million at Ameren Illinois Electric Distribution and an increase in the net loss for activity not reported as part of a segment, primarily at Ameren (parent), of $2 million.

Earnings per share in 2024, compared with 2023, were favorably affected by:

• increased allowance for equity funds used during construction and increased base rate revenues for the inclusion of previously deferred PISA and RESRAM interest charges pursuant to the June 2023 MoPSC electric rate order effective July 9, 2023, and decreased interest charges resulting from higher deferrals related to infrastructure investments associated with the PISA and RESRAM, at Ameren Missouri (17 cents per share);

• increased rate base investments at Ameren Transmission, which increased earnings in this segment (16 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 net effect of 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 (9 cents per share);

• increased retail electric sales volumes at Ameren Missouri, primarily due to higher sales excluding customer energy-efficiency programs (estimated at 8 cents per share);

• increased other income, net, primarily due to lower donations and a gain on the extinguishment of debt, see Note 5 – Long-term Debt and Equity Financings under Part II, Item 8, of this report for more information, partially offset by decreased non-service cost components of net periodic benefit income not subject to formula rates or trackers largely due to lower investment returns (6 cents per share);

• increased base rate revenues at Ameren Illinois Natural Gas effective November 28, 2023, pursuant to the November 2023 ICC natural gas rate order, partially offset by increased depreciation and amortization expenses included in base rates (4 cents per share);

• decreased other operations and maintenance expenses not subject to formula rates, riders, or trackers, excluding a charge related to the NSR and Clean Air Act litigation discussed below largely because of lower energy center maintenance costs, lower storm costs, disciplined cost management including lower labor costs from decreased headcount and decreased use of contractors, and lower amortization of refueling costs for the Callaway Energy Center, partially offset by the absence of regulatory deferrals associated with the June 2023 MoPSC rate order (2 cents per share).

Earnings per share in 2024, compared with 2023, were unfavorably affected by:

• a charge recorded by Ameren Missouri, included in other operation and maintenance expenses, related to an order from the United States District Court for the Eastern District of Missouri, which resolved all outstanding claims in the NSR and Clean Air Ac t litigation related to the Rush Island Energy Center, see Note 14 - Commitments and Contingencies under Part II, Item 8, of this report for more information (17 cents per share);

• increased financing costs primarily at Ameren Missouri and Ameren (parent), largely due to higher long-term debt balances and interest rates, partially offset by lower levels of short-term borrowings (17 cents per share);

• lower revenue at Ameren Illinois Electric Distribution due to a lower recognized ROE under the MYRP (9 cents per share);

The increase was due to net income increases of $188 million, $92 million, $47 million, and $9 million at Ameren Missouri, Ameren Transmission, Ameren Illinois Electric Distribution, and Ameren Illinois Natural Gas, respectively.

These increases were partially offset by an increase in net loss of $62 million for activity not reported as part of a segment, primarily at Ameren (parent).

Earnings per diluted share in 2025, compared with 2024, were favorably affected by:

• increased base rate revenues at Ameren Missouri effective June 1, 2025, pursuant to the April 2025 MoPSC electric rate order and a lower base level of expenses, partially offset by financing costs otherwise recoverable under the PISA and RESRAM, depreciation and amortization on property, plant, and equipment previously eligible for deferral under the PISA and RESRAM, and the net recovery for amounts associated with the reduction in sales volumes resulting from MEEIA programs (42 cents per share);

• decreased income tax expense at Ameren Transmission, Ameren Illinois Electric Distribution and Ameren Illinois Natural Gas resulting from the revaluation of excess deferred income tax regulatory liabilities, resulting from TCJA for FERC-regulated and ICC-regulated jurisdictions, related to ratemaking treatment of net operating loss carryforwards by affiliates under a tax allocation agreement, see Note 12 – Income Taxes under Part II, Item 8, of this report for additional information (32 cents per share);

• increased retail electric sales volumes at Ameren Missouri, excluding customer energy-efficiency programs, primarily due to warmer July temperatures and colder winter temperatures, and growth in weather-normalized retail electric sales (estimated at 22 cents per share);

• the absence of a 2024 charge recorded by Ameren Missouri, included in other operation and maintenance expenses, related to a settlement agreement with the United States Department of Justice that resolved all outstanding claims in the NSR and Clean Air Act litigation related to the Rush Island Energy Center, see Note 14 - Commitments and Contingencies under Part II, Item 8, of this report for additional information (17 cents per share);

• increased base rate revenues at Ameren Missouri for the inclusion of previously deferred interest charges pursuant to the April 2025 MoPSC electric rate order effective June 1, 2025, and higher interest deferrals related to infrastructure investments associated with the PISA and RESRAM (17 cents per share);

• increased rate base investments at Ameren Transmission and Ameren Illinois Electric Distribution (14 cents per share);

• the absence of the October 2024 FERC order reducing the allowed base ROE for FERC regulated transmission rate base and required refunds for certain prior periods under the MISO tariff, which increased Ameren Transmission earnings (4 cents per share);

• a higher allowance for equity funds used during construction at Ameren Transmission (4 cents per share).

Earnings per diluted share in 2025, compared with 2024, were unfavorably affected by:

• increased financing costs primarily due to higher interest rates on higher debt balances at Ameren Missouri and Ameren (parent) (24 cents per share);

• increased other operations and maintenance expenses not subject to formula rates, riders, or trackers, excluding a 2024 charge related to the NSR and Clean Air Act litigation discussed above, largely because of higher vegetation management costs, higher storm costs, higher energy center maintenance expense, and higher cloud computing costs at Ameren Missouri (18 cents per share);

• increased weighted-average basic common shares outstanding resulting from issuances of common shares (8 cents per share);

• the result of the October 2024 FERC order reducing the allowed base ROE for FERC regulated transmission rate base under the MISO tariff, which decreased Ameren Transmission earnings (4 cents per share);

• increased taxes other than income taxes at Ameren Missouri, largely resulting from the absence in 2024 of employee retention tax credits received under the Coronavirus Aid, Relief, and Economic Security Act (2 cents per share).

• increased losses related to equity method investments at Ameren Transmission and Ameren (parent) (4 cents per share).

The cents per share variances above are presented based on the weighted-average basic shares outstanding in 2024 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 2025 blended federal and state statutory tax rate of 26%.

For additional details regarding the Ameren Companies’ results of operations, including explanations of Operating Revenues for both Electric Revenues and Natural Gas Revenues;

For additional details regarding the Ameren Companies’ results of operations, including explanations of Operating Revenues for both Electric Revenues and Natural Gas

Fuel and Purchased Power Expenses;

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Effect of weather (estimate) (c)

66 — — — — 66

Retail sales volumes and changes in customer usage patterns (excluding the estimated effects of weather and MEEIA) 20 — — — — 20

Customer charges 2 — — — — 2

(23) — — — — (23)

Rush Island Energy Center base rate revenue deferral (13) — — — — (13)

MEEIA 2019 performance incentives 1 — — — — 1

Securitized utility tariff bond surcharges 46 — — — — 46

Off-system sales, capacity, transmission, and FAC revenues, net 452 — — — — 452

Recovery of power restoration efforts provided to other utilities 1 3 — — — 4

Ameren Illinois energy-efficiency program investment revenues — 12 — — — 12

Electric deferred income tax adjustment (d)

— (23) — — — (23)

Other 4 18 — — (6) 16

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Base rates (estimate) $ 9 $ — $ 4 $ — $ — $ 13

Sales volume (excluding the estimated effects of weather) 2 — — — — 2

Effect of weather (estimate) (c)

12 — — — — 12

Other 1 — — — — 1

2 unchanged sentences

Other cost recovery mechanisms (f)

(2) — 7 — — 5

Total natural gas revenue change $ 18 $ — $ 30 $ — $ — $ 48

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this variation is based on temperature readings from National Oceanic and Atmospheric Administration weather stations at local airports in our service territories.

(d) The electric deferred income tax adjustment relates to certain excess deferred income taxes that will be amortized through 2025.

Offsetting expense increases or decreases are reflected within "Income Taxes" on the statement of income.

This item has no overall impact on earnings.

(d) Changes in RESRAM revenues are largely offset in “Fuel and purchased power,” “Other operations and maintenance,” “Depreciation and amortization,” “Taxes other than income taxes,” or “Income taxes” on the statement of income.

(e) Electric and natural gas revenue changes are offset by corresponding changes in “Fuel and purchased power” and “Natural gas purchased for resale” on the statement of income.

Activity in Other/Intersegment Eliminations of $12 million represents the changes in eliminations of related-party transactions between Ameren Missouri, Ameren Illinois, and ATXI (-$6 million), as well as changes in Ameren Transmission revenue from transmission services provided to Ameren Illinois Electric Distribution

(-$6 million).

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.

Activity in Other/Intersegment Eliminations of $41 million was due to changes in Ameren Transmission revenue from transmission services provided to Ameren Illinois Electric Distribution (-$41 million).

See Note 16 – Segment Information under Part II, Item 8, of this report for additional information on intersegment eliminations.

These items have no overall impact on earnings.

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Electric Revenues

Ameren’s electric revenues increased $101 million, or 2%, in 2024, compared with 2023 , due to increased revenues at Ameren Missouri and Ameren Transmission, partially offset by decreased revenues at Ameren Illinois Electric Distribution, as discussed below.

Ameren’s electric revenues increased $1,128 million, or 17%, in 2025, compared with 2024 , due to increased revenues at Ameren Missouri, Ameren Illinois, and Ameren Transmission, as discussed below.

Ameren Transmission

Amer en Transmission’s electric revenues increased $81 million, or 10%, in 2025, compared with 2024.

Revenues were favorably affected by higher recoverable expenses (+$55 million), increased capital investment (+$44 million), as evidenced by a 15% increase in rate base used to calculate the revenue requirement, and increased facility rental revenues (+$15 million) related to ATXI’s transmission operations control center, which was placed in service in December 2023.

ATXI provides affiliates with access to this facility.

Rental revenues associated with this facility are affiliate transactions and eliminated in consolidation for Ameren’s consolidated financial statements.

See Note 13 – Related-party Transactions under Part II, Item 8, of this report for additional information.

Revenues were unfavorably affected by a decrease in the allowed base ROE under the MISO tariff resulting from the October 2024 FERC order, which included customer refunds for certain historical periods (-$10 million).

See Note 2 – Rate and Regulatory Matters under Part II, Item 8, of this report for additional information regarding the FERC complaint cases.

Revenues were favorably affected by higher recoverable expenses (+$47 million) and increased capital investment (+$24 million), as evidenced by a 7% increase in rate base used to calculate the revenue requirement.

Additionally, revenues were favorably affected by the absence of the October 2024 FERC order that decreased base ROE for certain historical periods (+$10 million).

Ameren Missouri

Ameren Missouri’s electric revenues increased $784 million , or 20% , in 2025, compared with 2024.

The following items had a favorable effect on Ameren Missouri’s electric revenues in 2024, compared with 2023:

• “Off-system sales, capacity, transmission, and FAC revenues, net” increased $96 million, primarily due to higher summer and fall capacity prices which were set by annual MISO auctions.

• Higher electric base rates, resulting from the June 2023 MoPSC electric rate order effective July 9, 2023, increased revenues an estimated $62 million .

• Excluding the estimated effects of weather and the MEEIA customer energy-efficiency programs, electric revenues increased an estimated $27 million , due to an increase in residential customer counts, retail sales volumes from large commercial and industrial customers, the absence of customer outages resulting from major storms experienced throughout the service territory in July and August 2023, and an additional day in 2024 as a result of the leap year.

The increase is partially offset by lower realized prices due to changes in customer usage patterns and economic development discounts.

• Revenues associated with other cost recovery mechanisms increased $22 million , primarily due to an increase in RESRAM revenues and an increase in excise taxes due to increased retail sales revenue.

• Other revenues increased $6 million due to pole rents (+$2 million), other rentals (+$2 million), and other miscellaneous revenues

(+$2 million).

• The aggregate effect of weather increased revenues an estimated $3 million as cooling degree days increased 7% and heating degree days decreased 4%.

The following ite ms had an unfavorable effect on Ameren Missouri’s electric revenues in 2024, compared with 2023:

The following items increased Ameren Missouri’s electric revenues in 2025, compared with 2024:

• “Off-system sales, capacity, transmission, and FAC revenues, net” increased $452 million, primarily due to summer capacity prices increasing from $30 per MW-day in 2024 to $667 per MW-day in 2025 pursuant to the April 2025 annual MISO capacity auction.

• Higher electric base rates, excluding the change in base rates for the MEEIA customer energy-efficiency programs and the RESRAM, resulting from the April 2025 MoPSC electric rate order effective June 1, 2025, increased revenues an estimated $249 million .

See Note 2 – Rate and Regulatory Matters under Part II, Item 8, of this report for additional information regarding the April 2025 MoPSC electric rate order.

• The effect of weather increased revenues an estimated $66 million primarily due to warmer July temperatures and colder winter temperatures.

• Revenues increased $46 million due to surcharges related to the servicing of securitized utility tariff bonds issued in December 2024 to finance costs related to the accelerated retirement of the Rush Island Energy Center.

This increase in revenue is offset by increases in interest and amortization expense.

See Variable Interest Entities in Note 1 – Summary of Significant Accounting Policies under Part II, Item 8, of this report for additional information.

• Excluding the estimated effects of weather and the MEEIA customer energy-efficiency programs, electric revenues increased an estimated $20 million, primarily due to increased retail sales volumes, partially offset by lower realized prices due to changes in customer usage patterns.

The following ite ms decreased Ameren Missouri’s electric revenues in 2025, compared with 2024:

• RESRAM revenues decreased $23 million.

The changes in revenue are largely offset by changes in the “Depreciation and amortization” section of the statement of income.

• In accordance with the June 2024 MoPSC financing order, revenues decreased $13 million due to the deferral of base rate revenues to a regulatory liability related to the Rush Island Energy Center since its October 15, 2024 retirement date.

The deferral ended with new rates effective June 1, 2025.

• Revenues associated with “Cost recovery mechanisms – offset in fuel and purchased power” decreased $12 million, due to decreased 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 changes to “Cost recovery mechanisms - offset in electric revenue” in fuel and purchased power.

The regulatory liability will be refunded to customers in a future rate proceeding.

Ameren Illinois

Ameren Illinois’ electric revenues decreased $51 million, or 2%, in 2024, compared with 2023, driven by decreased revenues at Ameren Illinois Electric Distribution, partially offset by increased revenues at Ameren Illinois Transmission.

Ameren Illinois’ electric revenues increased $342 million, or 13%, in 2025, compared with 2024, driven by increased revenues at Ameren Illinois Electric Distribution and Ameren Illinois Transmission.

Ameren Illinois Electric Distribution

Ameren Illinois Electric Distribution’s revenues decreased $129 million, or 6%, in 2024, compared with 2023.

The following items had an unfavorable effect on Ameren Illinois Electric Distribution’s revenues in 2024, compared with 2023:

• Revenues associated with “Cost recovery mechanisms – offset in fuel and purchased power” decreased $193 million, due to decreased purchased power expenses recovered from customers.

The decreases in electric revenues are fully offset by decreases in purchased power expenses under cost recovery mechanisms for purchased power, as discussed below.

• Pursuant to an ICC order, revenues decreased $23 million, due to an increase in the amortization rate for certain excess deferred income taxes.

The following items had a favorable effect on Ameren Illinois Electric Distribution’s revenues in 2024, compared with 2023:

• Other cost recovery mechanisms increased revenues by $45 million, primarily due to a higher amount of bad debt and purchased receivables from alternative retail electric suppliers included in customer rates pursuant to their associated riders, partially offset by lower environmental remediation revenues.

• Revenues associated with customer energy-efficiency program investments increased $21 million, due to the recovery of program expenses (+$15 million), an increase in the ROE (+$4 million) primarily due to maximum achievement of the annual 2023 energy savings goals, and increased investment of $2 million.

• Base rates increased revenues by $14 million, primarily due to higher recoverable non-purchased power expenses (+$38 million), partially offset by a lower recognized ROE (-$24 million).

The MYRP utilizes a fixed ROE approved by the ICC of 8.72%, with adjustments for any performance incentives and penalties, while the IEIMA formula-based ROE was based on the annual average of the monthly yields of the 30-year United States Treasury bonds plus 580 basis points (9.84% as of December 31, 2023).

• The recovery of labor and benefit costs for crews assisting other utilities with power restoration efforts, primarily caused by hurricane damage, increased revenues by $3 million.

Ameren Illinois Electric Distribution’s revenues increased $310 million, or 15%, in 2025, compared with 2024.

The following items increased Ameren Illinois Electric Distribution’s revenues in 2025, compared with 2024:

• Revenues associated with “Cost recovery mechanisms – offset in fuel and purchased power” increased $201 million, due to increased purchased power expenses recovered from customers.

The increases in electric revenues are fully offset by increases in purchased power expenses under cost recovery mechanisms for purchased power, as discussed below.

• Base rates increased revenues by $96 million, due to higher recoverable non-purchased power expenses (+$76 million), increased capital investment (+$11 million), and the results of the 2024 annual revenue requirement reconciliation proceeding recognized in 2025

(+$9 million).

• Other revenues increased $18 million, primarily due to the recovery of and return on increased customer generation rebates and mutual assistance provided to Ameren Missouri for major storms experienced in 2025 throughout its service territory.

• Revenues associated with customer energy-efficiency program investments increased $12 million, due to the recovery of and return on increased energy-efficiency program investments under performance-based formula ratemaking.

Other cost recovery mechanisms decreased revenues by $17 million, primarily due to lower bad debt costs on purchased receivables from alternative retail electric suppliers and environmental remediation revenues that are included in customer rates pursuant to their associated riders.

Ameren Illinois Transmission

Ameren Illinois Transmission’s revenues increased $73 million , or 13% , in 2025, compared with 2024.

Base rate revenues were favorably affected by higher recoverable expen ses (+$58 million) and increased capital investment (+$33 million), as e videnced by a 17% increase in rate base used to calculate the revenue requirement .

Base rate revenues were unfavorably affected by a decrease in the allowed base ROE under the MISO tariff resulting from the October 2024 FERC order, which included customer refunds for certain historical periods (-$7 million).

See Note 2 – Rate and Regulatory Matters under Part II, Item 8, of this report for additional information regarding the FERC ROE complaint cases.

Base rate revenues were favorably affected by higher recoverable expen ses (+$48 million) and increased capital investment (+$18 million), as e videnced by an 8% increase in rate base used to calculate the revenue requirement .

Additionally, revenues were favorably affected by the absence of the October 2024 FERC order that decreased base ROE for certain historical periods (+$7 million).

Natural Gas Revenues

Ameren’s natural gas revenues increased $22 million , or 2% , in 2024, compared with 2023, due to increased revenues at Ameren Illinois Natural Gas, partially offset by decreased revenues at Ameren Missouri, as discussed below.

Ameren’s natural gas revenues increased $48 million , or 4% , in 2025, compared with 2024, due to increased revenues at Ameren Illinois Natural Gas and Ameren Missouri, as discussed below.

Ameren Missouri

Ameren Missouri’s natural gas revenues decreased $19 million, or 12%, in 2024, compared with 2023.

Revenues associated with “Cost recovery mechanisms – offset in natural gas purchased for resale” decreased $20 million in 2024, compared with 2023, due to lower commodity prices and the absence of amortization of natural gas costs deferred under the PGA related to the extremely cold weather in mid-February 2021.

Changes in natural gas revenues under the PGA are fully offset by corresponding changes in natural gas purchased for resale expenses.

Ameren Missouri’s natural gas revenues increased $18 million, or 12%, in 2025, compared with 2024, primarily due to colder winter temperatures and the effect of higher natural gas base rates as a result of the natural gas rate order effective September 1, 2025.

Ameren Illinois Natural Gas

Ameren Illinois Natural Gas’ revenues increased $30 million, or 3%, in 2025, compared with 2024.

Revenues increased an estimated $47 million due to higher natural gas base rates as a result of the November 2023 natural gas rate order, and revenues associated with other cost recovery mechanisms increased $7 million primarily due to increased revenues for excise taxes.

“Cost recovery mechanisms – offset in natural gas purchased for resale” decreased revenues $16 million, due to lower collection of natural gas costs previously deferred under the PGA.

Changes in natural gas revenues under the PGA are fully offset by the decrease in natural gas purchased for resale expenses.

“Cost recovery mechanisms – offset in natural gas purchased for resale” increased revenues $23 million, due to a higher collection of natural gas costs previously deferred under the PGA.

Changes in natural gas revenues under the PGA are fully offset by changes in natural gas purchased for resale expenses.

Fuel and Purchased Power

5 unchanged sentences

Energy costs (excluding the estimated effect of weather) $ 459 $ — $ — $ — $ — $ 459

Effect of higher net energy costs included in base rates 22 — — — — 22

Retail sales volumes 6 — — — — 6

Effect of weather (estimate) (a)

11 — — — — 11

Transmission service charges 10 — — — — 10

Other (1) — — — (2) (3)

Cost recovery mechanisms – offset in electric revenue (a)

Cost recovery mechanisms – offset in electric revenue (b)

(12) 201 — — (41) 148

Total fuel and purchased power change $ 467 $ 201 $ — $ — $ (43) $ 625

(a) “Cost recovery mechanisms — offset in electric revenue” changes are offset by corresponding changes in “Cost recovery mechanisms — offset in fuel and purchased power” in electric revenues.

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.

(a) Represents the estimated variation resulting from changes in cooling and heating degree-days on electric demand compared with the prior year;

variation is based on temperature readings from the National Oceanic and Atmospheric Administration weather stations at local airports in our service territories.

(b) “Cost recovery mechanisms — offset in electric revenue” changes are offset by corresponding changes in “Cost recovery mechanisms — offset in fuel and purchased power” in electric revenues.

See Note 16 – Segment Information under Part II, Item 8, of this report for additional information on intersegment eliminations.

These items have no overall impact on earnings.

Ameren Missouri and Ameren Illinois are generally allowed to pass on to customers prudently incurred costs for fuel and purchased power.

Ameren’s electric fuel and purchased power expenses decreased $131 million, or 7%, in 2024, compared with 2023, primarily due to decreased fuel and purchased power expenses at Ameren Illinois Electric Distribution, partially offset by increased fuel and purchased power expenses at Ameren Missouri, as discussed below.

Ameren’s electric fuel and purchased power expenses increased $625 million, or 37%, in 2025, compared with 2024, primarily due to increased fuel and purchased power expenses at Ameren Missouri and Ameren Illinois Electric Distribution, as discussed below.

Ameren Missouri

1 unchanged sentence

The following items increased Ameren Missouri’s fuel and purchased power expense in 2025, compared with 2024:

• Energy costs increased $95 million in 2024, compared with 2023, primarily due to higher summer and fall capacity prices, which were set by annual MISO auctions.

Ameren Missouri’s 5% exposure to net energy cost variances under the FAC is the difference between “Off-system sales, capacity, transmission, and FAC revenues, net” and “Energy costs (excluding the estimated effect of weather)”.

These results had an immaterial impact on earnings in 2024, compared with 2023.

• The effect of higher net energy costs included in base rates increased Ameren Missouri’s fuel and purchased power expenses $22 million in 2024, compared with 2023, as a result of the June 2023 MoPSC electric rate order.

• Transmission service charges increased $8 million due to higher transmission rates related to increased revenue requirements of other transmission operators.

• Increases in retail sales volumes increased Ameren Missouri’s fuel and purchased power expenses $6 million.

• Energy costs increased $459 million in 2025, compared with 2024, primarily due to summer capacity prices increasing from $30 per MW-day in 2024 to $667 per MW-day in 2025 pursuant to the April 2025 annual MISO capacity auction.

Ameren Missouri’s 5% exposure to net energy cost variances under the FAC of $7 million is the difference between “Off-system sales, capacity, transmission, and FAC revenues, net” in electric revenues and “Energy costs (excluding the estimated effect of weather)”.

• Fuel and purchased power expenses increased an estimated $11 million due to an increase in electric retail sales related to weather.

• Transmission service charges (not included in the FAC) increased $10 million due to higher transmission rates related to increased revenue requirements of other MISO transmission operators.

“Cost recovery mechanisms — offset in electric revenue” decreased $12 million in 2025, compared with 2024, due to decreased amortization of costs previously deferred under the FAC.

1 unchanged sentence

Ameren Illinois Electric Distribution

Ameren Illinois Electric Distribution’s purchased power expenses decreased $193 million, or 21%, in 2024, compared with 2023, primarily due to decreased energy prices (-$94 million), which largely reflect the results of IPA procurement events, decreased capacity prices (-$77 million), which were set by annual MISO auctions, and lower volumes (-$43 million) primarily due to residential and small commercial customers switching from Ameren Illinois’ supplied power to alternative retail electric suppliers and customer adoption of solar technology through initiatives required under Illinois law.

These decreases in purchased power expenses were partially offset by increased expenses associated with the amortization of renewable energy credit costs (+$20 million).

Ameren Illinois Electric Distribution’s purchased power expenses increased $201 million, or 27%, in 2025, compared with 2024, primarily due to summer capacity prices increasing from $30 per MW-day in 2024 to $667 per MW-day in 2025 pursuant to the April 2025 annual MISO capacity auction (+$69 million), increased volumes (+$61 million), primarily due to residential and small commercial customers switching from alternative retail electric suppliers to Ameren Illinois’ supplied power, increases in transmission service charges (+$46 million), and increased energy prices (+$25 million).

The changes to “Cost recovery mechanisms - offset in electric revenue” are fully offset by changes to “Cost recovery mechanisms - offset in fuel and purchased power” in electric revenues.

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Ameren Missouri and Ameren Illinois are allowed to pass on to customers prudently incurred costs for natural gas purchased for resale.

Ameren’s natural gas purchased for resale expenses decreased $35 million, or 10%, in 2024, compared with 2023, due to decreased natural gas purchased for resale expenses at Ameren Missouri and Ameren Illinois Natural Gas, as discussed below.

Ameren’s natural gas purchased for resale expenses increased $28 million, or 9%, in 2025, compared with 2024, due to increased natural gas purchased for resale expenses at Ameren Illinois Natural Gas, as discussed below.

Ameren Missouri

Ameren Missouri’s natural gas purchased for resale expenses decreased $19 million, or 24%, in 2024, compared with 2023.

Expenses associated with “Cost recovery mechanisms – offset in natural gas revenue” decreased $20 million in 2024, compared with 2023, due to lower commodity prices and the absence of amortization of natural gas costs deferred under the PGA related to the extremely cold weather in mid-February 2 021.

Changes in natural gas purchased for resale expenses are fully offset by corresponding changes in natural gas revenues under the PGA.

Ameren Missouri’s natural gas purchased for resale expenses were comparable in 2025, compared with 2024.

Ameren Illinois Natural Gas

Ameren Illinois Natural Gas’ natural gas purchased for resale expenses decreased $16 million, or 6%, in 2024, compared with 2023, primarily due to lower amortization of natural gas costs that were previously deferred under the PGA and lower natural gas prices.

Ameren Illinois Natural Gas’ natural gas purchased for resale expenses increased $23 million, or 9%, in 2025, compared with 2024, due to the amortization of natural gas costs that were previously deferred under the PGA.

Changes in natural gas purchased for resale expenses are fully offset by changes in natural gas revenues under the PGA.

7 unchanged sentences

Other operations and maintenance expenses increased $5 million in 2025, compared with 2024 because of the changes discussed below.

In addition to changes by segment as discussed below, other operations and maintenance expenses decreased $34 million in 2024 for activity not reported as part of a segment, as reflected in “Other/Intersegment Eliminations” above, primarily because of a $14 million increase in the elimination of intercompany rent related to ATXI’s operations control center discussed below;

a $10 million increase in the elimination of the non-service cost component of net periodic benefit income at Ameren Services;

and a $8 million gain on the sale of land.

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.

In addition to changes by segments discussed below, other operations and maintenance expenses decreased $18 million for activity not reported as part of a segment, as reflected in “Other/Intersegment Eliminations” above.

This is primarily due to a decrease of $21 million in the elimination of the non-service cost component of net periodic benefit income and other miscellaneous income and expenses.

The non-service cost component of net periodic benefit cost or income and other miscellaneous income and expenses at Ameren Services is allocated to the segments and primarily included in the segments’ other operations and maintenance expenses.

The decreases are offset by the absence of a gain on the sale of land of $8 million that occurred in 2024.

Ameren Transmission

Other operations and maintenance expenses increased $10 million in 2024, compared with 2023, primarily because of increased costs related to ATXI’s operations control center, which was placed in service in December 2023.

ATXI provides affiliates with access to this facility.

The rent expense associated with this facility is an affiliate transaction and eliminated in consolidation for purposes of Ameren’s consolidated financial statements.

See Note 13 - Related-party Transactions under Part II, Item 8, of this report for additional information.

Other operations and maintenance expenses were comparable between periods.

Ameren Missouri

Other operations and maintenance expenses increased $47 million in 2024, compared with 2023, primarily due to the following items:

• A $59 million charge related to an order from the United States District Court for the Eastern District of Missouri, which resolved all outstanding claims in the NSR and Clean Air Act litigation related to the Rush Island Energy Center, see Note 14 - Commitments and Contingencies under Part II, Item 8 , of this report for more information.

• The absence in 2024 of the recognition of regulatory assets for previously expensed costs approved for recovery pursuant to the June 2023 MoPSC rate order increased expenses $15 million.

• Individually insignificant increases of $7 million in various other operations and maintenance expenses, including other labor, cloud computing costs, and a decrease in the cash surrender value of COLI.

• The absence of previously deferred expenses increased expense by $7 million.

• Legal and administrative expenses increased by $6 million, primarily related to environmental matters.

• Costs for injuries and damages increased $4 million, primarily due to an increase in claims.

• Renewable development costs increased $3 million, primarily due to the absence in 2024 of the MoPSC order approving CCNs for the Boomtown and Huck Finn energy centers in the first half of 2023 that led to increased capitalization of renewable development costs pursuant to anticipated recovery from customers.

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

• Pension and benefit costs decreased $20 million because of a lower base level of expenses, subject to a tracker, included in customer rates pursuant to the June 2023 MoPSC electric rate order.

See Note 10 - Retirement Benefits under Part II, Item 8, of this report for more information.

• Energy center maintenance decreased $17 million, primarily because of lower amortization of Callaway Energy Center refueling and maintenance costs resulting from cost saving initiatives in the fall 2023 outage, compared to the spring 2022 outage, and lower headcount.

• Transmission and distribution storm-related costs decreased $10 million because of the major storms experienced throughout the service territory in July and August 2023.

• Transmission and distribution expenditures, excluding major storm-related costs, decreased $8 million, primarily due to reduced levels of vegetation management expenditures and lower inspection costs from decreased use of contractors, and lower headcount.

Other operations and maintenance expenses decreased $21 million in 2025, compared with 2024, primarily due to the following items:

• The absence in 2025 of a $59 million charge, related to the NSR and Clean Air Act litigation associated with the Rush Island Energy Center, see Note 14 - Commitments and Contingencies under Part II, Item 8, of this report for additional information.

• Expenses associated with the MEEIA customer energy-efficiency program decreased $23 million as approved by the MoPSC in November 2024.

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

• Non-nuclear generation operations and maintenance expenses, primarily at Sioux and Labadie energy centers, increased $16 million.

• Increased expense of $13 million for cloud-related software.

• Transmission and distribution expenditures, excluding major storm-related expenses, increased $12 million, largely due to increased vegetation management expenditures.

• Injuries and damages increased $9 million, primarily due to an increase in claims compared to the prior year.

• Transmission and distribution storm-related expenses increased $8 million, primarily because of the major storms experienced throughout its service territory in 2025.

• Bad debts increased $6 million, primarily because of a decline in collections experience.

Ameren Illinois

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Ameren Illinois Electric Distribution

Other operations and maintenance increased $87 million in 2024, compared with 2023, was primarily due to the following items:

• Bad debt costs increased $52 million, primarily because of a higher base level of expenses included in customer rates pursuant to the associated rider.

• Amortization of previous deferrals associated with bad debt costs on purchased receivables increased $15 million, primarily because of a higher base level of expenses included in customer rates pursuant to the associated rider.

Other operations and maintenance increased $37 million in 2025, compared with 2024, primarily due to the following items:

• Increased costs of $17 million resulting from expanding programs under CEJA.

• Distribution expenditures increased $10 million, primarily due to increased levels of reliability and other maintenance activity.

• Increased costs associated with customer energy-efficiency investments under formula ratemaking of $10 million, primarily due to amortization of regulatory assets.

• Benefit costs increased $6 million, primarily due to an increase in medical benefit claims related to active plan participants.

• Increased labor expense of $5 million, primarily caused by reduced capital expenditures due to steps taken to align operations with the MYRP orders, resulting in more maintenance activities.

• Absence of major storm-related cost deferrals in 2024 increased expense by $4 million.

• Vegetation management costs increased by $4 million due to increased activity.

• Labor expense increased by $3 million due to assistance provided to other utilities to aid in storm recovery efforts, primarily caused by hurricane damage.

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

• Increased expense of $8 million for cloud-related software.

• Increased costs related to demand response programs of $7 million.

• Injuries and damages increased $6 million, primarily due to an increase in claims compared to the prior year.

The above increases were partially offset by the following items:

• Bad debt costs on purchased receivables decreased $17 million, primarily because of a lower base level of expenses included in customer rates pursuant to the associated rider.

• Reduction in environmental remediation rider costs of $8 million.

• Technology-related expenditures decreased $3 million resulting from lower levels of software licenses and rentals.

Ameren Illinois Natural Gas

Other operations and maintenance costs decreased $7 million in 2024, compared with 2023, primarily due to a decrease of $6 million in contractor service costs and a $4 million decrease in labor expense due to steps taken to align operations with the November 2023 ICC natural gas rate order.

These decreases were partially offset by an increase of $2 million in cloud computing costs.

Other operations and maintenance costs were comparable between periods.

Ameren Illinois Transmission

Other operations and maintenance expenses increased $8 million in 2024, compared with 2023, primarily because of increased costs related to ATXI’s operations control center, which was placed in service in December 2023.

ATXI provides affiliates with access to this facility.

The rent expense associated with this facility is an affiliate transaction and eliminated in consolidation for purposes of Ameren’s consolidated financial statements.

See Note 13 - Related-party Transactions under Part II, Item 8, of this report for additional information.

Other operations and maintenance costs were comparable between periods.

Depreciation and Amortization Expenses

Total by Segment (a)

Increase by Segment

Overall Ameren Increase of $203 Million

Increase (Decrease) by Segment

Overall Ameren Decrease of $22 Million

(a) Includes other/intersegment eliminations of $8 million and $8 million in 2025 and 2024, respectively.

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Ameren Illinois Electric Distribution Ameren Transmission

Depreciation and amortization expenses increased $203 million, $134 million, and $63 million at Ameren, Ameren Missouri, and Ameren Illinois, respectively, primarily because of additional property, plant, and equipment investments across their respective segments.

In addition, Ameren’s and Ameren Missouri’s depreciation and amortization expenses were affected by the following items, which include the effect of the additional investments at Ameren Missouri:

• The deferral to a regulatory liability related to production tax credits allowed under the IRA associated with the Callaway Energy Center that increased expenses by $90 million.

• Increased depreciation and amortization of $40 million due to the inclusion in base rates of amounts previously deferred under the PISA and RESRAM effective July 9, 2023, pursuant to the June 2023 MoPSC electric rate order.

• Increased amortization of prior deferrals and the lower net under-recovery of RESRAM eligible expenses increased depreciation and amortization expenses by $33 million.

• Depreciation and amortization rate changes pursuant to the electric rate order noted above, which increased depreciation and amortization expenses by $4 million.

• Depreciation and amortization expenses reflected a deferral to a regulatory asset of depreciation associated with investments in eligible property, plant, and equipment not yet included in base rates, pursuant to PISA and RESRAM.

Base rates were updated to include the eligible property, plant, and equipment in-service through December 31, 2022, when new customer rates became effective on July 9, 2023, pursuant to the June 2023 MoPSC electric rate order.

The effect of rebasing PISA and RESRAM, partially offset by increased amortization of prior PISA deferrals, decreased depreciation and amortization by $30 million.

• The higher net deferral pursuant to a tracker related to certain excess deferred income taxes, which decreased depreciation and amortization expenses by $5 million.

Depreciation and amortization expenses decreased $22 million and $57 million at Ameren and Ameren Missouri, respectively, and increased $33 million at Ameren Illinois.

Ameren Illinois depreciation and amortization expenses increased primarily because of additional property, plant, and equipment investments.

Ameren’s and Ameren Missouri’s depreciation and amortization expenses were affected by the following items, which include the effect of the additional investments at Ameren Missouri:

• The absence of a 2024 deferral to a regulatory liability associated with production tax credits allowed under the IRA applicable to the Callaway Energy Center and the related amortization in 2025, which decreased depreciation and amortization expenses by $100 million.

• The higher net under-recovery of RESRAM eligible expenses and lower amortization of prior deferrals decreased depreciation and amortization expenses by $37 million.

• The absence of depreciation expense associated with the retirement of Ameren Missouri’s Rush Island Energy Center in 2024 decreased expenses by $27 million.

• Increased depreciation and amortization of $36 million due to the inclusion in base rates of property, plant, and equipment previously eligible for deferral to a regulatory asset under the PISA and RESRAM effective June 1, 2025, pursuant to the April 2025 MoPSC electric rate order.

• The amortization of a regulatory asset associated with the securitization of Ameren Missouri’s Rush Island Energy Center increased depreciation and amortization expenses by $22 million.

Base rates were updated to include the eligible property, plant, and equipment in-service through December 31, 2024, when new customer rates became effective on June 1, 2025, pursuant to the April 2025 MoPSC electric rate order.

The effect of rebasing PISA and increased amortization of prior PISA deferrals, increased depreciation and amortization by $14 million.

• Increased amortization and lower deferral pursuant to a tracker related to certain excess deferred income taxes, which increased depreciation and amortization expenses by $13 million.

• Depreciation and amortization rate changes effective June 1, 2025, pursuant to the April 2025 MoPSC electric rate order, which increased depreciation and amortization expenses by $9 million.

Taxes Other Than Income Taxes

Total by Segment (a)

Increase by Segment

Increase (Decrease) by Segment

Overall Ameren Increase of $30 Million

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Ameren Illinois Electric Distribution Ameren Transmission

Taxes other than income taxes increased $25 million in 2024, compared with 2023, primarily because of an increase of $7 million and $2 million at Ameren Missouri and Ameren Illinois Electric Distribution, respectively, due to the absence in 2024 of employee retention tax credits received under the Coronavirus Aid, Relief, and Economic Security Act;

a $9 million increase at Ameren Illinois Natural Gas due to an increase in excise taxes, primarily resulting from higher invested capital taxes;

and a $3 million increase in gross receipts taxes at Ameren Missouri, primarily due to increased retail electric sales.

Taxes other than income taxes increased $30 million in 2025, compared with 2024, primarily because of an increase of $21 million, $7 million, and $4 million at Ameren Missouri, Ameren Illinois Electric Distribution and Ameren Illinois Natural Gas, respectively.

Taxes other than income taxes increased primarily due to an increase in gross receipts taxes of $20 million, $6 million, and $4 million at Ameren Missouri, Ameren Illinois Natural Gas, and Ameren Illinois Electric Distribution, respectively, resulting from increased retail electric and natural gas sales.

Other Income, Net

Total by Segment Increase (Decrease) by Segment

Overall Ameren Increase of $69 Million

Total by Segment Decrease by Segment

Overall Ameren Decrease of $70 Million

Ameren Missouri Ameren Illinois Natural Gas Other/Intersegment Eliminations

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See Note 5 – Long-term Debt and Equity Financings and Note 10 – Retirement Benefits under Part II, Item 8, for additional information on the debt extinguishment and the non-service cost components of net periodic benefit income.

Other income, net, increased $69 million in 2024, compared with 2023.

In addition to changes discussed below, other income, net, increased $14 million for activity not reported as part of a segment, primarily due to lower charitable contributions of $18 million at Ameren (parent) and a gain of $16 million for Ameren (parent)’s repurchase of senior secured notes and first mortgage bonds issued by Ameren Missouri and first mortgage bonds issued by Ameren Illinois.

These increases were partially offset by a decrease of $13 million due to the non-service cost component of net periodic benefit income for activity not reported as part of a segment and $7 million in intersegment eliminations.

Other income, net, decreased $70 million in 2025, compared with 2024.

In addition to the changes discussed below, other income, net, decreased $36 million for activity not reported as part of a segment, due to a decrease of $20 million in the non-service cost component of net periodic benefit income and a decrease of $6 million in income from equity method investments, primarily associated with investments to advance innovative energy technologies.

Ameren Transmission

Other income, net, decreased $2 million in 2024, compared with 2023 due to a decrease of $5 million in lower allowance for equity funds used during construction, primarily related to lower average construction work in progress balances and a decrease of $2 million in the non-service cost component of net periodic benefit income.

These decreases were partially offset by the increase of $4 million in other interest income on regulatory balances.

Other income, net, decreased $2 million in 2025, compared with 2024, primarily due to a $9 million impairment of an equity method investment and a decreas e of $5 million for individually insignificant items.

These decreases were offset by a $12 million increase in the allowance for equity funds used during construction, primarily resulting from a decreased level of short-term borrowings included in the calculation and higher average construction work in progress balances.

Ameren Missouri

Other income, net, increased $66 million in 2024, compared with 2023, primarily because of an increase of $42 million in the non-service cost component of net periodic benefit income because of changes in the base level of pension and postretirement costs pursuant to the June 2023 MoPSC electric rate order.

Other income, net, also increased $28 million because of a higher allowance for equity funds used during construction resulting from higher average construction work in progress balances.

These increases were offset by a decrease of $2 million in other interest income on regulatory balances.

Other income, net, decreased $16 million in 2025, compared with 2024, primarily due to a decrease of $13 million in the reduction in non-service cost component of net periodic benefit income and an increase of $5 million in charitable donations.

Ameren Illinois

Other income, net, decreased $9 million in 2024, compared with 2023.

Other income, net, decreased primarily because of a decrease of $12 million and $6 million in the non-service cost component of net periodic benefit income at Ameren Illinois Electric Distribution and Ameren Illinois Natural Gas, respectively.

Other income, net decreased $2 million in the allowance of equity funds used during construction, largely at Ameren Illinois Electric Distribution.

These decreases were partially offset by the increase in other interest income on regulatory balances of $11 million, largely at Ameren Illinois Electric Distribution.

Other income, net, decreased $11 million in 2025, compared with 2024, primarily due to a decrease of $24 million in the non-service cost component of net periodic benefit income, largely at Ameren Illinois Electric Distribution and Ameren Illinois Natural Gas.

The decreases are partially offset by a $13 million increase in the allowance for equity funds used during construction, largely at Ameren Illinois Transmission.

Interest Charges

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Interest charges increased $113 million in 2025, compared with 2024.

In addition to changes by segments discussed below, interest charges increased $42 million for activity not reported as part of a segment, primarily at Ameren (parent), because of issuances of long-term debt in November and December of 2023, which collectively increased interest charges by $64 million.

The net proceeds from these issuances were used to repay short-term borrowings, which decreased short-term interest expense by $23 million, compared with 2023.

In addition to changes by segments discussed below, interest charges increased $46 million at Ameren (parent), because of increased levels of short-term borrowings that increased interest charges by $20 million.

Additionally, interest charges increased $25 million at Ameren (parent), due to a long-term debt issuance in March 2025, partially offset by the repayment of a senior unsecured note in September 2024.

Ameren Transmission

Interest charges increased $21 million in 2024, compared with 2023, primarily due to issuances of long-term debt in May 2023, June 2024 and August 2024, which collectively increased interest charges by $9 million.

Additionally, an increase on long-term debt and a higher interest rate on an increased level of short-term borrowings increased interest charges by $8 million and $2 million, respectively.

Interest charges were comparable between periods.

Ameren Missouri

Interest charges increased $17 million in 2024, compared with 2023, primarily due to issuances of long-term debt in March 2023, January 2024, April 2024, and October 2024, which collectively increased interest charges by $48 million.

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

• Increase in the borrowed funds capitalized as part of the allowance for funds used during construction of $12 million, primarily due to higher average construction work in progress balances.

• Interest charges decreased by $9 million due to the maturity of $350 million senior secured notes bearing a 3.5% interest rate in April 2024 that were repaid with cash on hand.

• Interest charges reflected a deferral to a regulatory asset of interest associated with investments in eligible property, plant, and equipment not yet included in base rates, pursuant to PISA and RESRAM.

This update to base rates resulted in a higher deferral of interest in 2024 pursuant to PISA and RESRAM that decreased interest charges by $5 million.

• Lower levels of short-term borrowings decreased interest charges by $4 million.

Interest charges increased $53 million in 2025, compared with 2024, primarily due to the issuances of long-term debt in April 2024, October 2024, and April 2025 which increased interest by $45 million.

Interest charges also increased by $22 million due to the December 2024 issuance of securitized utility tariff bonds associated with the retirement of the Rush Island Energy Center, see Note 5 - Long-Term Debt and Equity Financing under Part II, Item 8, in this report for more information.

Additionally, the amount of interest charges included in base rates for PISA and RESRAM was updated when new customer rates became effective on June 1, 2025, pursuant to the April 2025 MoPSC electric rate order.

Lower deferrals 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 $30 million.

The above increases were partially offset by interest charges that reflected a deferral to a regulatory asset of interest associated with investments in eligible property, plant and equipment not yet reflected in rates pursuant to PISA and RESRAM, which decreased interest charges by $44 million.

Ameren Illinois

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Ameren Illinois Transmission

Interest charges increased by $20 million, primarily due to issuances of long-term debt in May 2023 and June 2024, which increased interest charges by $10 million.

Additionally, an increase of interest on long-term debt, a higher interest rate on an increased level of short-term borrowings, and interest charges resulting from the October 2024 FERC ROE order increased interest charges by $4 million, $2 million, and $2 million, respectively.

Interest charges increased by $8 million, p rimarily because of issuances of long-term debt in March and September 2025 and June 2024, which increased interest expense by $14 million.

The increases were partially offset by $3 million due to a lower interest rate on decreased levels of borrowing on short-term debt and by $3 million due to the maturity of a senior secured note in June 2025.

Ameren Illinois Electric Distribution

Interest charges increased by $9 million, primarily due to issuances of long-term debt in May 2023 and June 2024, which increased interest charges by $11 million.

Interest charges increased by $9 million, primarily because of issuances of long-term debt in March and September 2025 and June 2024, which increased interest expense by $16 million.

The increases were partially offset by $3 million due to the maturity of a senior secured note in June 2025 and by $2 million due to a lower interest rate on decreased levels of borrowing on short-term debt.

Ameren Illinois Natural Gas

Interest charges increased by $8 million, primarily due to issuances of long-term debt in May 2023 and June 2024.

Interest charges were comparable between periods.

The following table presents effective income tax rates for the years ended December 31, 2025 and 2024:

Ameren 7% 14%

Ameren Missouri 5% (18)%

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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.

The effective tax rate was lower at Ameren Illinois Electric Distribution in 2024, compared with 2023, primarily due to an increase in excess deferred tax amortization pursuant to an ICC order, which was offset by a corresponding decrease in revenues.

The effective tax rate was lower at Ameren Illinois Electric Distribution, Ameren Illinois Natural Gas, Ameren Illinois Transmission, and Ameren Transmission compared with the prior year due to a revaluation of excess deferred income tax regulatory liabilities in 2025.

In 2024, the IRS issued a series of private letter rulings to another taxpayer, which provided guidance on applying IRS normalization rules to the calculation of tax benefits applicable to the ratemaking treatment related to net operating loss carryforwards.

The rulings concluded that, for ratemaking purposes, net operating loss carryforwards should be reflected on a separate company basis and should not be reduced by payments received for the utilization of losses by other affiliates under a tax allocation agreement.

In 2025, the FERC issued an order reflecting implementation of the rules for the other taxpayer who had a similar fact pattern as Ameren Illinois and ATXI.

In addition, in 2025, the ICC issued orders in Ameren Illinois’ 2024 electric distribution service revenue requirement reconciliation adjustment proceeding and in its January 2025 natural gas rate review addressing the impacts of the private letter rulings.

Accordingly, in 2025, Ameren and Ameren Illinois decreased income tax expense by $86 million and $61 million, respectively, to reflect the revaluation of excess deferred income tax regulatory liabilities resulting from TCJA for FERC-regulated and ICC-regulated jurisdictions pursuant to IRS guidance and recent FERC and ICC orders.

LIQUIDITY AND CAPITAL RESOURCES

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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.

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 $2.1 billion, $1.0 billion, and, $1.1 billion, respectively, which include $0.8 billion, $0.3 billion, and, $0.5 billion, respectively, in 2025.

Further, for additional information about Ameren’s and Ameren Missouri’s obligations associated wtih operating leases, see Note 15 – Supplemental Information.

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.

respectively, in 2026.

Further, for additional information about Ameren’s and Ameren Missouri’s obligations associated with operating leases, see Note 15 – Supplemental Information.

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 expected increases in demand, overall system reliability, grid modernization, renewable energy target requirements, and other improvements.

For additional information about our long-term debt outstanding, including maturities due within one year, and the applicable interest rates, see 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 2030.

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.

Additionally, Ameren may offer and sell from time to time common stock, including under its ATM program, which includes the ability to enter into forward sale agreements, subject to market conditions and other factors.

During 2025, Ameren issued a total of 5.8 million shares of common stock and received aggregate proceeds of $530 million under the ATM program.

As of December 31, 2024, Ameren had multiple forward sale agreements that could be settled under the ATM program with various counterparties relating to 2.5 million shares of common stock.

Including issuances under the DRPlus and employee benefit plans, Ameren plans to issue approximately $600 million of equity each year from 2025 to 2029.

As of December 31, 2025, Ameren had multiple forward sale agreements with various counterparties relating to 6.4 million shares of common stock, which it expects to settle in 2026.

Ameren’s equity financing plan is estimated to be approximately $4 billion from 2026 to 2030.

This plan includes equity issuances under forward sales agreements, the DRPlus, and employee benefit plans, and could include issuances of hybrid debt securities.

Ameren expects the financing plans to be aligned with the timing of generation investments.

In August 2025, Ameren increased the amount of common stock available for sale under the ATM program by $1.25 billion to a total of $3 billion.

As of December 31, 2025, Ameren had approximately $1.5 billion of common stock remaining available for sale under the ATM program.

The Ameren Companies expect their equity to total capitalization and cash flow metrics 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.

See Note 5 – Long-term Debt and Equity Financings under Part II, Item 8, of this report for additional information on the ATM program and forward sale agreements relating to common stock, including those under the ATM program.

The following table presents net cash provided by (used in) operating, investing, and financing activities for the years ended December 31, 2025 and 2024:

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129 (1,484) (1,466) (18) 28 165 (137)

(a) Both Ameren and Ameren Illinois’ cash provided by operating activities included cash outflows of $125 million and $123 million for the FEJA electric energy-efficiency rider and $39 million and $9 million for the customer generation rebate program in 2024 and 2023, respectively.

(a) Both Ameren and Ameren Illinois’ cash provided by operating activities included cash outflows of $123 million and $125 million for the electric energy-efficiency rider and $54 million and $39 million for the customer generation rebate program in 2025 and 2024, respectively.

Cash Flows from Operating Activities

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The following items contributed to the increase:

• A $201 million increase resulting from increased customer collections primarily from base rate increases effective July 9, 2023, at Ameren Missouri pursuant to the June 2023 electric rate order, base rate increases effective November 28, 2023, at Ameren Illinois pursuant to the November 2023 natural gas rate order and electric transmission rate base growth, and increased customer collections under cost recovery mechanisms at Ameren Illinois, partially offset by lower customer collections under cost recovery mechanisms at Ameren Missouri.

• A $68 million increase in income tax refunds, net, due to the transfer of production and investment tax credits to unrelated parties and higher income tax refunds primarily due to lower taxable income compared to 2023, mainly driven by the adoption of IRS-issued guidance for the 2024 tax year that provided a safe harbor method of accounting for the capitalization or deduction of certain

expenditures to maintain, repair, replace, or improve natural gas distribution property.

• A $37 million increase due to higher purchases of materials and supplies inventories in 2023 to support operations as levels were increased to mitigate against potential supply disruptions.

• A $33 million increase due to the absence of nuclear refueling and maintenance outage payments in 2024 related to the Callaway Energy Center.

The last scheduled refueling and maintenance outage was in the fall of 2023.

• A $24 million increase due to higher major storm restoration costs in 2023, primarily at Ameren Illinois, due to storms in the summer of 2023.

• A $22 million increase due to insurance proceeds received in 2024 related to workers’ compensation payments made in the 2023 at Ameren Illinois.

• A $20 million increase due to higher coal purchases in 2023 to bring coal inventories back to targeted levels after transportation delays experienced in 2022.

• A $20 million decrease in payments related to charitable donations.

• A $16 million increase due to workers’ compensation payments made in 2023 at Ameren Illinois.

• A $636 million increase resulting from higher customer collections primarily from higher electric and natural gas sales volumes due to warmer July temperatures and colder winter temperatures in 2025, increased base rates at Ameren Missouri effective June 1, 2025, pursuant to the April 2025 MoPSC electric rate order, and at Ameren Illinois, electric distribution and transmission base rate increases and higher customer collections under cost recovery mechanisms.

• A $219 million increase due to the transfer of production and investment tax credits to unrelated parties.

• A $27 million increase due to the timing of payments for spent nuclear fuel storage and reimbursements from the DOE.

• A $24 million increase due to the timing of payments for accounts payable.

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

• A $148 million increase in net collateral posted with counterparties, primarily due to changes in the market prices of power, natural gas, and other fuels.

• A $65 million increase in interest payments, primarily due to an increase in the average outstanding debt and an increase in interest rates.

• A $144 million increase in interest payments, primarily due to higher average outstanding debt and interest rates on long-term debt.

• A $43 million increase in payments for the spring 2025 refueling and maintenance outage at the Callaway Energy Center.

There was no outage in 2024.

• A $29 million increase in gross receipts tax payments due to an increase in sales in 2025 compared to 2024.

• A $25 million increase in payments for coal deliveries, primarily due to increased generation at Ameren Missouri’s coal-fired energy centers in 2025.

• A $23 million increase in payments to contractors at Ameren Illinois, primarily related to higher levels of reliability and other maintenance activity and costs to comply with the CEJA.

• A $22 million decrease due to the absence of insurance proceeds received in 2024 related to workers’ compensation claims at Ameren Illinois.

• Ameren Missouri paid $19 million during 2025 to fund mitigation programs ordered in the NSR and Clean Air Act litigation discussed in Note 14 – Commitments and Contingencies under Part II, Item 8, of this report.

• A $14 million increase in restoration expenses related to major storms in 2025.

• A $10 million increase in the cost of natural gas held in storage, primarily at Ameren Illinois, due to changes in the market price of natural gas.

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The following items contributed to the increase:

• A $117 million increase in income tax refunds, net, due to the transfer of production and investment tax credits to unrelated parties, as well as an income tax refund from Ameren (parent), pursuant to the tax allocation agreement, primarily due to lower taxable income compared to 2023.

• A $49 million increase resulting from increased customer collections primarily from base rate increases effective July 9, 2023, pursuant to the June 2023 electric rate order, partially offset by lower customer collections under cost recovery mechanisms.

• A $40 million increase due to higher purchases of materials and supplies inventories in 2023 to support operations as levels were increased to mitigate against potential supply disruptions.

• A $33 million increase due to the absence of nuclear refueling and maintenance outage payments in 2024 related to the Callaway Energy Center.

The last scheduled refueling and maintenance outage was in the fall of 2023.

• A $31 million increase due to the timing of payments for accounts payable and prepaid expenses.

• A $20 million increase due to higher coal purchases in 2023 to bring coal inventories back to targeted levels after transportation delays experienced in 2022.

• A $219 million increase due to the transfer of production and investment tax credits to unrelated parties.

• A $218 million increase resulting from higher customer collections primarily from higher electric sales volumes due to warmer July temperatures and colder winter temperatures in 2025 and increased base rates effective June 1, 2025, pursuant to the April 2025 MoPSC electric rate order, partially offset by lower customer collections under cost recovery mechanisms.

• A $27 million increase due to the timing of payments for spent nuclear fuel storage and reimbursements from the DOE.

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

• A $99 million increase in net collateral posted with counterparties, primarily due to changes in the market prices of power, natural gas, and other fuels.

• A $19 million increase in interest payments, primarily due to an increase in the average outstanding debt and an increase in interest rates.

• A $68 million increase in interest payments, primarily due to higher average outstanding debt and interest rates on long-term debt.

• A $43 million increase in payments for the spring 2025 refueling and maintenance outage at the Callaway Energy Center.

There was no outage in 2024.

• A $25 million increase in payments for coal deliveries, primarily due to increased generation at coal-fired energy centers in 2025.

• Payments of $19 million during 2025 to fund mitigation programs ordered in the NSR and Clean Air Act litigation discussed in Note 14 – Commitments and Contingencies under Part II, Item 8, of this report.

• A $17 million increase in gross receipts tax payments due to an increase in sales in 2025 compared to 2024.

• An $11 million decrease due to the timing of payments for accounts payable.

• An $8 million increase in restoration expenses related to major storms in 2025.

Ameren Illinois

Ameren Illinois’ cash provided by operating activities increased $271 million in 2024, compared with 2023.

The following items contributed to the increase:

• A $148 million increase due to an income tax refund from Ameren (parent), pursuant to the tax allocation agreement, primarily due to lower taxable income compared to 2023, mainly driven by the adoption of IRS issued guidance for the 2024 tax year that provided a safe harbor method of accounting for the capitalization or deduction of certain expenditures to maintain, repair, replace, or improve natural gas distribution property.

• A $139 million increase resulting from increased customer collections primarily from base rate increases effective November 28, 2023, pursuant to the November 2023 natural gas rate order and electric transmission rate base growth, and by increased customer collections under cost recovery mechanisms.

• A $34 million increase due to the timing of payments for accounts payable and prepaid expenses.

• A $22 million increase due to insurance proceeds received in 2024 related to workers’ compensation payments made in 2023.

• A $20 million increase due to workers’ compensation payments made in 2023.

• A $19 million increase due to higher major storm restoration costs in 2023 due to storms in the summer of 2023.

Ameren Illinois’ cash provided by operating activities increased $129 million in 2025, compared with 2024 primarily due to a $410 million increase resulting from higher customer collections primarily from higher electric and natural gas distribution sales volumes due to warmer July temperatures and colder winter temperatures in 2025, electric distribution and transmission base rate increases, and higher customer collections under cost recovery mechanisms.

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

• A $43 million increase in net collateral posted with counterparties, primarily due to changes in the market prices of power and natural gas.

• A $164 million increase in income tax payments to Ameren (parent), pursuant to the tax allocation agreement, primarily due to higher taxable income compared to 2024.

Taxable income was lower in 2024 due to the adoption of IRS guidance that provided a safe harbor method of accounting for the capitalization or deduction of certain expenditures to maintain, repair, replace, or improve natural gas distribution property.

The adoption of this guidance resulted in an adjustment for all years prior to 2024.

• A $29 million increase in interest payments, primarily due to higher average outstanding long-term debt and interest rates on long-term debt.

• A $23 million increase in payments to contractors, primarily related to higher levels of reliability and other maintenance activity and costs to comply with the CEJA.

• A $22 million decrease due to the absence of insurance proceeds received in 2024 related to workers’ compensation claims.

• A $12 million increase in gross receipts tax payments due to an increase in sales in 2025 compared to 2024.

• A $9 million increase in the cost of natural gas held in storage due to changes in the market price of natural gas.

• An $18 million increase in interest payments, primarily due to an increase in the average outstanding debt and an increase in interest rates.

• A $6 million increase in restoration expenses related to major storms in 2025.

Cash Flows from Investing Activities

Ameren’s cash used in investing activities increased $658 million during 2024, compared with 2023, primarily as a result of a $722 million increase in capital expenditures, largely resulting from the acquisitions and completion of the Cass County, Boomtown, and Huck Finn energy centers at Ameren Missouri.

Ameren’s increase in capital expenditures was partially offset by decreased expenditures for electric transmission infrastructure upgrades, reduced expenditures for electric distribution infrastructure upgrades and natural gas infrastructure upgrades due to steps taken by Ameren Illinois to align its 2024 operations with the ICC’s MYRP orders and November 2023 natural gas rate order, and due to decreased storm-related expenditures of $92 million at Ameren Illinois.

Ameren’s cash used in investing activities was also partially offset by an $83 million decrease due to the timing of nuclear fuel expenditures.

Ameren Missouri’s cash used in investing activities increased $938 million during 2024, compared with 2023, primarily as a result of a $952 million increase in capital expenditures, largely resulting from the acquisitions and completion of the Cass County, Boomtown, and Huck Finn energy centers.

Ameren Missouri’s cash used in investing activities also increased as a result of a $43 million increase in net money pool advances, and was partially offset by an $83 million decrease due to the timing of nuclear fuel expenditures.

Ameren Illinois’ cash used in investing activities decreased $267 million during 2024, compared with 2023, due to a decrease in capital expenditures, largely resulting from decreased expenditures for electric transmission infrastructure upgrades.

Ameren Illinois’ capital expenditures also decreased as a result of reduced expenditures for electric distribution infrastructure upgrades and natural gas infrastructure upgrades due to steps taken by Ameren Illinois to align its 2024 operations with the ICC’s MYRP orders and November 2023 natural gas rate order, and due to decreased storm-related expenditures of $92 million.

Ameren’s cash used in investing activities decreased $311 million during 2025, compared with 2024, primarily as a result of a $191 million decrease in capital expenditures, largely resulting from the completion of the Cass County, Boomtown, and Huck Finn energy centers at Ameren Missouri in 2024.

In addition, Ameren’s cash used in investing activities also decreased by $54 million due to a withdrawal of funds related to the cash surrender value of COLI and by $45 million due to the timing of nuclear fuel expenditures at Ameren Missouri.

Ameren Missouri’s cash used in investing activities decreased $369 million during 2025, compared with 2024, primarily as a result of a $210 million decrease in capital expenditures, largely resulting from the completion of the Cass County, Boomtown, and Huck Finn energy centers in 2024.

Ameren Missouri’s cash used in investing activities also decreased as a result of an $86 million decrease in money pool advances, net, and $45 million due to the timing of nuclear fuel expenditures.

Ameren Illinois’ cash used in investing activities increased $18 million during 2025, compared with 2024, due to an increase in capital expenditures, largely resulting from increased expenditures for natural gas and electric distribution infrastructure upgrades as well as increased expenditures related to major storms, partially offset by decreased expenditures for electric transmission infrastructure.

Capital Expenditures

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2024 – Total Ameren $4,319 (a)

Ameren Missouri (b)

Ameren Illinois Natural Gas ATXI and other electric transmission subsidiaries

Ameren Missouri Ameren Illinois Natural Gas ATXI and other electric transmission subsidiaries

Ameren Illinois Electric Distribution Ameren Illinois Transmission

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Additionally, the Ameren Companies invested in various software projects.

The following table presents Ameren’s estimate of capital expenditures that will be incurred from 2025 through 2029, including construction expenditures, allowance for funds used during construction, and expenditures for compliance with existing environmental regulations:

The following table presents Ameren’s estimate of capital expenditures that will be incurred from 2026 through 2030, including construction expenditures and allowance for funds used during construction:

2026 2027 – 2030 Total

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Ameren $ 5,520 $ 24,955 – $ 27,580 $ 30,475 – $ 33,100

Ameren Missouri’s estimated capital expenditures include transmission, distribution, grid modernization, and generation-related investments, primarily renewable and natural gas generation, as well as expenditures for compliance with environmental regulations .

Ameren Missouri’s estimated capital expenditures include transmission, distribution, grid modernization, and generation-related investments, primarily renewable and natural gas generation and battery storage, consistent with the 2025 Change to the 2023 PRP.

Ameren Illinois’ estimated capital expenditures are primarily for electric and natural gas transmission and distribution-related investments.

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Investments under the plan are expected to total approximately $20.8 billion over the five-year period from 2026 through 2030, with expenditures largely recoverable under the PISA.

See Note 14 – Commitments and Contingencies under Part II, Item 8, of this report, for additional information on the EPA regulations.

The Smart Energy Plan excludes investments in its natural gas distribution business, as well as removal costs, net of salvage.

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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, significant changes in environmental regulations, 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.

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.

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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 began substation upgrades in 2024 in advance of transmission line construction, which is expected to begin in spring 2026, with forecasted completion dates near the end of this decade.

In addition, the MISO awarded three competitive bid projects to ATXI that represent a total estimated investment of approximately $220 million for ATXI.

Also in December 2024, the MISO approved a first set of second tranche projects.

Also in 2024, the MISO approved a first set of second tranche projects.

A portion of these projects were assigned to Ameren and are estimated to cost approximately $1.3 billion, based on the MISO’s cost estimate.

The competitive bid process is expected to take place through 2026.

The MISO is assessing future long-range transmission scenarios in the first quarter of 2025 and development of a second set of second tranche projects will follow this assessment.

The first set of second tranche projects also includes competitive bid projects.

The remaining competitive bid projects that have not been awarded are estimated to cost $4.4 billion, which includes projects located in Illinois that are estimated to cost $1.7 billion, based on the MISO’s cost estimate.

The competitive bid process is expected to continue through 2026.

Environmental Capital Expenditures

Ameren Missouri will continue to incur costs to comply with federal and state regulations, including those requiring the reduction of SO 2 , NO x , CO 2 , and mercury emissions from its coal-fired energy centers, compliance with the CCR Rule, and potential modifications to cooling water 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.

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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 $459 million during 2024, compared with 2023.

During 2024, Ameren utilized net proceeds of $2.5 billion from the issuance of long-term debt for capital expenditures, to repay then-outstanding short-term debt, to repay $49 million of maturities of long-term debt at ATXI, and to finance energy transition costs related to the accelerated retirement of the Rush Island Energy Center, which included the remaining unrecovered net plant balance associated with the facility, among other costs .

In addition, Ameren utilized proceeds from net commercial paper issuances of $607 million, aggregate cash proceeds of $273 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 repay $800 million of long-term debt maturities at Ameren (parent) and Ameren Missouri, and to fund, in part, capital expenditures.

In comparison, in 2023, Ameren utilized net proceeds of $2.3 billion from the issuance 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 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.

Ameren’s cash provided by financing activities decreased $865 million during 2025, compared with 2024.

During 2025, Ameren utilized net proceeds from the issuance of long-term debt of $2.0 billion for general corporate purposes and to repay $300 million of long-term debt maturities and then-outstanding short-term debt.

During 2025, Ameren also repaid net short-term debt of $499 million.

In addition, Ameren

utilized aggregate cash proceeds of $574 million from the issuance of common stock under the ATM program, the DRPlus, and the 401(k) plan, along with cash provided by operating activities to fund, in part, capital expenditures.

In comparison, in 2024, Ameren utilized net proceeds of $2.5 billion from the issuance of long-term debt for capital expenditures, to repay then-outstanding short-term debt, to repay $49 million of maturities of long-term debt at ATXI, and to finance energy transition costs related to the accelerated retirement of the Rush Island Energy Center, which included the remaining unrecovered net plant balance associated with the facility, among other costs.

In addition, during 2024, Ameren utilized proceeds from net commercial paper issuances of $607 million , aggregate cash proceeds of $273 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 repay $800 million of long-term debt maturities at Ameren (parent) and Ameren Missouri, and to fund, in part, capital expenditures.

During 2025, Ameren paid common stock dividends of $768 million, compared with $714 million in dividend payments in 2024.

Ameren Missouri’s cash provided by financing activities increased $766 million during 2024, compared with 2023.

During 2024, Ameren Missouri utilized net proceeds of $1.8 billion from the issuance of long-term debt for capital expenditures, to repay then-outstanding short-term debt, and to finance energy transition costs related to the accelerated retirement of the Rush Island Energy Center, which included the remaining unrecovered net plant balance associated with the facility, among other costs .

In addition, Ameren Missouri repaid $350 million of long-term debt maturities, $170 million of net commercial paper borrowings, and $306 million of money pool borrowings.

Ameren Missouri’s cash provided by financing activities decreased $605 million during 2025, compared with 2024.

During 2025, Ameren Missouri utilized net proceeds of $500 million from the issuance of long-term debt to repay then-outstanding short-term debt.

In addition, during 2025, Ameren Missouri utilized proceeds from net commercial paper issuances of $471 million and cash provided by operating activities to fund, in part, capital expenditures.

I n comparison, in 2024, Ameren Missouri utilized net proceeds of $1.8 billion from the issuance of long-term debt for capital expenditures and to repay then-outstanding short-term debt, and to finance energy transition costs related to the accelerated retirement of the Rush Island Energy Center, which included the remaining unrecovered net plant balance associated with the facility, among other costs .

In addition, during 2024, Ameren Missouri repaid $350 million of long-term debt maturities, $170 million of net commercial paper borrowings, and $306 million of money pool borrowings.

During 2024 , Ameren Missouri also utilized capital contributions from Ameren (parent) of $476 million along with cash provided by operating activities to fund, in part, capital expenditures.

In comparison, in 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, during 2023, 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.

During 2025, Ameren Missouri also paid common stock dividends of $196 million.

Ameren Illinois’ cash provided by financing activities decreased $137 million during 2025, compared with 2024.

During 2024, Ameren Illinois utilized net proceeds of $624 million from the issuance of long-term debt to repay then-outstanding short-term debt.

During 2025, Ameren Illinois utilized net proceeds of $711 million from the issuance of long-term debt to repay $300 million of long-term debt maturities and then-outstanding short-term debt.

Ameren Illinois also repaid net commercial paper borrowings of $71 million and money pool borrowings of $37 million.

In comparison, in 2024, Ameren Illinois utilized net proceeds of $624 million from the issuance of long-term debt to repay then-outstanding short-term debt.

In addition, Ameren Illinois repaid net commercial paper borrowings of $277 million and money pool borrowings of $98 million.

During 2024 , Ameren Illinois also utilized capital contributions from Ameren (parent) of $36 million along with cash provided by operating activities to fund, in part, capital expenditures.

In comparison, in 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.

During 2025, Ameren Illinois paid common stock dividends of $265 million, compared with $110 million in dividend payments in 2024.

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Ameren (parent) commercial paper outstanding

Ameren Missouri commercial paper outstanding 471

Letters of credit

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See Note 5 – Long-term Debt and Equity Financings under Part II, Item 8, of this report for additional information.

The Credit Agreements, among other things, provide $2.6 billion of credit until maturity in December 2028.

In December 2025, the Credit Agreements, which were scheduled to mature in December 2028, were extended and now mature in December 2030.

The Credit Agreements provide $3.2 billion of credit through December 2030.

See Note 4 – Short-term Debt and Liquidity under Part II, Item 8, of this report for additional information on the Credit Agreements.

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The issuance of short-term debt securities by Ameren’s utility subsidiaries is subject to FERC approval under the Federal Power Act.

In January 2025, the FERC issued orders authorizing Ameren Missouri, Ameren Illinois, and ATXI to issue up to $1.4 billion, $1 billion, and $500 million, respectively, of short-term debt securities through January 2027.

In January 2025, the FERC issued orders authorizing ATXI to issue up to $500 million of short-term debt securities through January 2027.

In December 2025, the FERC issued orders authorizing Ameren Missouri and Ameren Illinois to issue up to $1.6 billion and $1.1 billion, respectively, of short-term debt securities through December 2027.

The Ameren Companies continually evaluate the adequacy and appropriateness of their liquidity arrangements for changing business conditions.

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Issuances of Long-term Debt

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

5.00% Senior unsecured notes due 2029 December — 699

5.375% Senior unsecured notes due 2035 March $ 749 $ —

Ameren Missouri:

5.25% First mortgage bonds due 2054 January — 347

5.45% First mortgage bonds due 2053 March — 499

5.25% First mortgage bonds due 2035 April 500 —

5.20% First mortgage bonds due 2034 April — 499

5.125% First mortgage bonds due 2055 October — 449

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Ameren Illinois:

4.95% First mortgage bonds due 2033 May — 498

5.625% First mortgage bonds due 2055 March 350 —

5.55% First mortgage bonds due 2054 June — 624

5.625% First mortgage bonds due 2055 September 361 —

5.17% Senior unsecured notes due 2039 August — 70

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Ameren Missouri:

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

3.50% Senior secured notes due 2024 April — 350

4.85% Securitized utility tariff bonds due 2039 (a)

Ameren Illinois:

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3.43% Senior unsecured notes due 2050 August — 49

Total Ameren long-term debt maturities $ 849 (g)

Total Ameren long-term debt maturities $ 317 (f)

(a) These securitized utility tariff bonds were issued by AMF.

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(e) Excludes 0.3 million and 0.2 million shares of common stock valued at $25 million and $16 million issued for no cash consideration in connection with stock-based compensation in 2025 and 2024, respectively.

(f) In January 2023, Ameren Missouri and Audrain County mutually agreed to terminate a financing obligation agreement related to the CT energy center in Audrain County, which was scheduled to expire in December 2023.

No cash was exchanged in connection with the termination of the agreement as the $240 million principal amount of the financing obligation due from Ameren Missouri was equal to the amount of bond service payments due to Ameren Missouri.

(g) Excludes Ameren (parent)’s November and December 2024 purchases of senior secured notes and first mortgage bonds issued by Ameren Missouri and first mortgage bonds issued by Ameren Illinois for $44 million in aggregate.

(f) Excludes Ameren (parent)’s 2025 and 2024 purchases of senior secured notes and first mortgage bonds issued by Ameren Missouri and first mortgage bonds issued by Ameren Illinois for $24 million and $44 million in the aggregate, respectively.

The Ameren Companies may sell securities registered under their effective registration statements if market conditions and capital requirements warrant such sales.

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At December 31, 2025, 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 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.

See Note 4 – Short-term Debt and Liquidity and Note 5 – Long-term Debt and Equity Financings

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.

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Issuer/corporate credit rating Baa1 BBB+

Senior debt A2 A

Senior unsecured debt Baa1 Not Rated

Secured debt A2 A

Commercial paper P-2 A-2

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Issuer/corporate credit rating A3 BBB+

Senior debt A1 A

Senior unsecured debt A3 BBB+

Secured debt A1 A

Commercial paper P-2 A-2

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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 $58 million for Ameren and Ameren Illinois at December 31, 2024.

A sub-investment-grade issuer or senior unsecured debt rating (below “Baa3” from Moody’s or below “BBB-” from S&P) at December 31, 2024, 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 $740 million, $699 million, and $41 million, respectively.

Cash collateral postings and prepayments made with external parties were immaterial and cash collateral posted by external parties was $70 million for Ameren and Ameren Illinois at December 31, 2025.

A sub-investment-grade issuer or senior unsecured debt rating (below “Baa3” from Moody’s or below “BBB-” from S&P) at December 31, 2025, 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 $1.2 billion, $1.1 billion, and $57 million, respectively.

Changes in commodity prices could trigger additional collateral postings and prepayments.

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protect water bodies;

manage the 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.

regulate the handling and disposal of hazardous substances and waste materials;

establish siting and land use requirements;

and protect against 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-related risks, that affect, or may affect, our facilities, operations, and capital expenditures to comply with such laws.

The combined effects of compliance with existing and future environmental regulations could result in significant capital expenditures, increased operating costs, and the potential for closure or alteration of operations at some of Ameren Missouri’s energy centers.

Additionally, international agreements have in the past, and could again, 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 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.

In accordance with the new presidential administration’s approach to United States energy policy, in January 2025, the United States withdrew from the Paris Agreement.

The current federal administration is expected to review, and has already revised, compliance requirements under a number of federal environmental regulatory programs;

however, differences in energy policy priorities adopted by future federal administrations could result in additional greenhouse gas reduction requirements in the United States.

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) environmental, social, governance and sustainability-related reporting program.

We also issue a periodic climate risk report aligned with the Task Force on Climate-related Financial Disclosures (TCFD) and a report on our management of CCR.

Additionally, we have posted a 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.

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 United States withdrew from the Paris Agreement and the United Nations Framework Convention on Climate Change in January 2025 and 2026, respectively.

The EPA has revised, and has proposed revisions to, compliance requirements under a number of federal environmental regulatory programs related to greenhouse gases;

however, differences in energy policy priorities adopted by future presidential administrations could result in additional greenhouse gas reduction requirements in the United States.

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 2026 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 and Note 14 – Commitments and Contingencies under Part II, Item 8, of this report.

• The PPRA became effective in August 2025.

The law made modifications to integrated resource planning, which requires Missouri electric utilities to file plans for meeting their customers' long-term energy needs.

By August 2027, the MoPSC will publish a schedule for Missouri electric utilities to file integrated resource plans every four years.

The MoPSC will be required to issue an order on the plans and shall determine whether the electric utility has submitted sufficient documentation and selected preferred resource plans representing a reasonable and prudent means of serving the utility's load obligations at just and reasonable rates.

In making this determination, the MoPSC shall consider whether the plans appropriately balance specific factors described in the law.

If the MoPSC approves the plans, requests for CCNs for new generation facilities to be constructed or acquired as a part of the approved plans shall be deemed necessary and convenient and the scope of the CCN proceedings to review projects will be limited.

The approved generation facilities will also be eligible to include construction work in progress in rate base, subject to MoPSC approval, which would improve the timeliness of cash recovery.

Utilities are not allowed to capitalize allowance for funds used during construction on amounts included in rate base under this provision.

The amount of construction work in progress to be included in rate base is limited to prudently incurred expenditures made within the construction period for the facility.

Separately, outside of the integrated resource planning process discussed above, the law allows a Missouri electric utility to request that the MoPSC authorize the inclusion of construction work in progress for new natural gas-fired generation facilities in rate base, subject to the same restrictions discussed above.

The provisions allowing for the inclusion of construction work in progress on natural gas-fired generation in rate base expire in December 2035, unless Ameren Missouri requests and receives MoPSC approval of an extension through 2045.

Also, beginning in July 2026 the law allows natural gas utilities to file regulatory rate reviews using a future test year, subject to MoPSC approval.

If a natural gas utility is allowed to use a future test year, a reconciliation of the actual rate base and certain forecasted costs will be performed 45 days after the end of the test year.

If a given year’s actual revenue requirement is less than the revenue requirement approved by the MoPSC due to changes in rate base or certain other costs, an adjustment is made to reduce natural gas operating revenues with an offset to a regulatory liability to reflect that test year’s amounts.

The regulatory liability will then be refunded to customers in the next regulatory rate review and will accrue carrying costs at the applicable WACC.

The law also made modifications to the PISA and requires electric utilities to submit service tariff schedules for certain large load customers as discussed below.

• 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.

Investments not eligible for recovery under the PISA include amounts related to new nuclear generation facilities and service to new customer premises.

Additionally, the PISA permits Ameren Missouri to earn a return at the applicable WACC on 85% of 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.

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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 2024, Ameren Missouri filed a request with the MoPSC seeking approval to increase its annual revenues for electric service.

In February 2025, Ameren Missouri filed an updated electric rate increase request seeking approval to increase its annual revenues for electric service by $446 million.

Ameren Missouri cannot predict the level of any electric service rate change the MoPSC may approve, whether the requested regulatory recovery mechanisms will be continued, or whether any rate change that may eventually be approved will be sufficient for Ameren Missouri to recover its costs and earn a reasonable return on its investments when the rate change goes into effect.

• In June 2024, the MoPSC issued a financing order authorizing the issuance of securitized utility tariff bonds by AMF related to the accelerated retirement of the Rush Island Energy Center.

The financing order also included a determination that the decision to retire the Rush Island Energy Center was reasonable and prudent.

The MoPSC did not make a determination regarding the prudency of Ameren Missouri's prior actions that resulted in the adverse ruling in the NSR and Clean Air Act litigation, however, claims regarding such actions could be considered in future regulatory proceedings.

Base rate revenues relating to the recovery of the Rush Island Energy Center are being deferred as a regulatory liability since the October 15, 2024 retirement date of the facility until new rates become effective related to the current electric service regulatory rate review.

The amortization period for the regulatory liability will be determined in a future regulatory rate review.

• In September 2024, Ameren Missouri filed a request with the MoPSC seeking approval to increase its annual revenues for natural gas delivery service by $40 million.

Ameren Missouri cannot predict the level of any natural gas delivery service rate change the MoPSC may approve, whether the requested regulatory recovery mechanisms will be continued, or whether any rate change that may eventually be approved will be sufficient for Ameren Missouri to recover its costs and earn a reasonable return on its investments when the rate change goes into effect.

• In November 2024, the MoPSC issued an order approving a nonunanimous stipulation and agreement for Ameren Missouri’s MEEIA 2025 plan, which includes a portfolio of customer energy-efficiency and demand response programs, along with the continued use of the MEEIA rider, which allows Ameren Missouri to collect from customers its actual MEEIA program costs, related lost electric revenues, and performance incentives.

Ameren Missouri intends to invest $51 million annually in 2025 and 2026 and $22 million in 2027 for customer energy-efficiency and demand response programs.

In addition, the order approved performance incentives applicable to each plan year to earn revenues by achieving certain spending and demand response goals.

If 100% of the goals are achieved in 2025, 2026, and 2027, Ameren Missouri would earn performance incentive revenues of $5 million, $5 million, and $2 million, respectively.

As a result of the PISA election, additional provisions of the law apply to Ameren Missouri, including limitations on electric customer rate increases caused by the inclusion of incremental PISA deferrals in the revenue requirement.

Pursuant to the PPRA discussed above, Ameren Missouri’s PISA election was extended through 2035 and an additional extension through 2040 is allowed if requested by Ameren Missouri and approved by the MoPSC.

This law also reduced the annual limit on increases to the electric service revenue requirement used to set customer rates, compared to the revenue requirement established in the immediately preceding rate order, due to the inclusion of incremental PISA deferrals in the

revenue requirement.

The annual limit in effect was 2.5% and changed to 2.25%, prorated monthly, for revenue requirements approved by the MoPSC after August 2025.

Ameren Missouri expects significantly higher investments in infrastructure eligible for PISA and AFUDC in 2026, compared to 2025.

• In April 2025, the MoPSC issued an order that authorized an increase of $355 million to Ameren Missouri’s annual revenue requirement for electric retail service, effective June 1, 2025.

The order changed annualized depreciation, regulatory asset and liability amortization amounts, and the base level of expenses for trackers.

As a result of this order, Ameren Missouri expects a year-over-year increase to 2026 earnings, compared to 2025, of approximately $30 million.

• In July 2025, the MoPSC issued an order in Ameren Missouri’s 2024 natural gas delivery service regulatory rate review, approving a unanimous stipulation and agreement.

The order authorized an increase of $32 million to Ameren Missouri’s annual revenue requirement for natural gas delivery service, effective September 1, 2025.

• The PPRA requires an electric utility to develop and submit to the MoPSC schedules that include its service tariff applicable to certain large load customers.

These schedules must reasonably ensure that such high-demand customers’ rates reflect a representative share of the costs incurred to serve them and must prevent other lower-demand customer rates from reflecting any unjust or unreasonable costs arising from service provided to these high-demand customers.

In February 2026, Ameren Missouri executed electric service agreements with large load customers consistent with the tariff terms discussed above, representing 2.2 gigawatts of demand.

Ameren and Ameren Missouri do not expect a material impact to their results of operations, financial position, or liquidity in 2026 related to these agreements.

• Ameren Illinois and ATXI use a forward-looking rate calculation with an annual revenue requirement reconciliation for each company’s electric transmission business.

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These rates will affect Ameren Illinois’ and ATXI’s cash receipts during 2026, but will not determine their respective electric transmission service operating revenues, which will instead be based on 2026 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.

In October 2024, the FERC issued an order, which decreased the allowed base ROE from 10.02% to 9.98% and required refunds, with interest, for the periods from November 2013 to February 2015 and from late September 2016 forward.

In January 2025, the same parties filed an appeal of the October 2024 order to the United States Court of Appeals for the District of Columbia Circuit.

In March 2020, the FERC issued a Notice of Proposed Rulemaking on its transmission incentives policy, which proposed to increase 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.

• In 2020, the FERC issued a Notice of Proposed Rulemaking on its transmission incentives policy, which proposed to increase 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 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.

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Ameren is unable to predict the ultimate impact of any changes to the FERC’s incentives policy.

point change in the FERC-allowed ROE would affect Ameren’s and Ameren Illinois’ annual net income by an estimated $17 million and $12 million, respectively, based on each company’s 2025 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 reconciled 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.

In December 2024, the ICC issued an order approving Ameren Illinois’ 2023 electric distribution service revenue requirement reconciliation adjustment filing.

This order approved a reconciliation adjustment of $158 million.

The approved reconciliation adjustment will be collected from customers in 2025.

A 50-basis-point change in the FERC-allowed ROE would affect Ameren’s and Ameren Illinois’ annual net income by an estimated $19 million and $14 million, respectively, based on each company’s 2026 projected rate base.

• Pursuant to the CEJA, 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.

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 reconcile electric distribution service rates to its actual revenue requirement on an annual basis, subject to a reconciliation cap and adjustments to the ROE.

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The RBA remains effective whether Ameren Illinois elects to file an MYRP or a traditional regulatory rate review.

In December 2025, the ICC issued an order approving Ameren Illinois’ 2024 electric distribution service revenue requirement reconciliation adjustment filing.

This order approved an adjustment increasing the allowed revenue requirement by $48 million, which will be collected from customers in 2026.

In February 2026, the ICC denied Ameren Illinois’ rehearing request to include an asset associated with other postretirement benefits in the rate base, among other things.

Ameren Illinois is assessing whether to pursue an appeal with the Illinois Appellate Court for the Fifth Judicial District in the first half of 2026.

• In December 2024, the ICC issued an order in connection with a revised Grid Plan and a revised MYRP filed by Ameren Illinois in March 2024, approving revenue requirements for electric distribution services for 2024 through 2027 of $1,206 million, $1,287 million, $1,367 million, and $1,421 million, respectively.

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Rate changes consistent with the December 2024 order became effective in December 2024.

Subsequently, in February 2025, the ICC denied the rehearing request.

Ameren Illinois intends to file an appeal of the ICC’s December 2024 order to the Illinois Appellate Court for the Fifth Judicial District.

In addition, Ameren Illinois has filed an appeal related to orders issued by the ICC in December 2023 and June 2024 related to this proceeding.

The appellate court is under no deadline to address the appeal, and Ameren Illinois cannot predict the ultimate outcome of the appeal.

• 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.

• In January 2026, the CRGA was enacted and will become effective in June 2026.

The law includes certain provisions that affect Ameren Illinois’ annual investments in energy-efficiency programs, and the related return on those investments.

Under the law, the annual spending cap for energy-efficiency investments will increase to $178 million, $222 million, and $256 million for 2027, 2028, and 2029, respectively.

In addition, beginning in 2027, the ROE component of the applicable WACC used to calculate Ameren Illinois’ return on energy-efficiency investments for the year will be that year’s ICC-approved ROE for Ameren Illinois’ electric distribution service.

The allowed ROE can be increased or decreased up to 200 basis points, depending on the achievement of annual energy savings and demand goals.

• Pursuant to Illinois law, Ameren Illinois’ electric energy-efficiency investments are deferred as a regulatory asset and earn a return at the applicable WACC.

Through 2026, the ROE component of the applicable WACC is based on the annual average of the monthly yields of the 30-year United States Treasury bonds plus 580 basis points.

Pursuant to the CRGA discussed above, beginning in 2027, the ROE component of the applicable WACC for a given year will be that year’s ICC approved ROE for Ameren Illinois’ electric distribution service.

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 and demand goals.

While the ICC has approved a plan for Ameren Illinois to invest approximately $126 million per year in electric energy-efficiency programs through 2029, 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.

Ameren Illinois expects to file its next electric energy-efficiency plan for 2026 through 2029 in late February 2025.

• In January 2025, Ameren Illinois filed a request with the ICC seeking approval to increase its annual revenues for natural gas delivery service by $140 million.

A decision by the ICC in this proceeding is required by early December 2025, with new rates expected to be effective in December 2025.

Ameren Illinois cannot predict the level of any delivery service rate change the ICC may approve, nor whether any rate change that may eventually be approved will be sufficient to enable Ameren Illinois to recover its costs and to earn a reasonable return on investments when the rate changes go into effect.

• The November 2023 order also directed the ICC staff to develop a plan for a future of gas proceeding.

Pursuant to the CRGA, Ameren Illinois is required to file an updated energy-efficiency plan for 2027 through 2029 by June 1, 2026 to reflect the spending cap increases discussed above.

• In November 2025, the ICC issued an order in Ameren Illinois’ January 2025 natural gas delivery service regulatory rate review, which resulted in an increase to its annual revenues for natural gas delivery service of $79 million.

The order reflected a reduction of $75 million of planned distribution and transmission capital investments included in Ameren Illinois’ future test year request.

The new rates became effective December 2025.

The court is under no deadline to address the appeal, and Ameren Illinois cannot predict the ultimate outcome of the appeal.

• A November 2023 ICC order 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 are included in this proceeding, which is exploring issues involving the 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 being 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.

A final ICC staff report is expected in early 2026 and will be used by the ICC to guide further action, if any.

• Ameren Missouri’s next refueling and maintenance outage at its Callaway energy center is scheduled for the spring of 2025.

A final ICC staff report is expected by the end of 2026 and will be used by the ICC to guide further action, if any.

• Ameren Missouri’s next refueling and maintenance outage at the Callaway Energy Center is scheduled for the fall of 2026.

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.

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In addition, Ameren Missouri may incur increased non-nuclear energy center maintenance costs in non-outage years.

• Pursuant to Illinois law, Ameren Missouri's natural gas-fired energy centers in Illinois are subject to annual limits on emissions, including CO 2 and NO x .

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.

• In late 2024 three turbines at the High Prairie Energy Center collapsed, resulting in significantly reduced operation of the energy center.

While the investigation into the cause of the collapse is ongoing, a large majority of the turbines at the energy center have returned to operation, and work is ongoing to restore the remaining turbines.

• 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, 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.

We expect a net increase in demand resulting from the electrification of the economy, including in the transportation sector.

In addition, a new 250-MW data center is expected to be constructed in Ameren Missouri’s service territory with electric service starting in 2026.

Several other entities in various industries, including data center and manufacturing, are considering either locating or expanding their operations within our service territories.

To serve these new loads, we expect increased investments will be necessary, including expected future investments for environmental compliance, system reliability improvements, and new generation sources, that will result in rate base and revenue growth but also higher depreciation and financing costs.

In addition, several entities in various industries, including data center, healthcare, manufacturing, distribution, warehousing, alternative energy, fabrication, and food production, are considering either locating or expanding their operations within our service territories.

In February 2026, Ameren Missouri executed electric service agreements with large load customers under the modified tariff as discussed above, representing 2.2 gigawatts of demand.

Construction agreements have been signed with developers representing 3.4 gigawatts of demand, which includes the executed electric service agreements.

Serving these new loads will require increased investments, including future investments for system reliability improvements and new generation sources, that will result in rate base growth.

Liquidity and Capital Resources

• In 2025 and 2026, the presidential administration took executive action to impose additional foreign trade tariffs on various goods imported from numerous countries, and several of these countries imposed retaliatory foreign trade tariffs in response.

Some of these foreign trade tariffs have been modified several times and/or paused for specific periods of time.

The Ameren Companies have not experienced material impacts on their results of operations, financial position, or liquidity to date, however the foreign trade tariffs may have future impacts.

The Ameren Companies will continue to assess the impact of such foreign trade tariffs or other potential presidential administrative action and take actions to mitigate risks associated with costs and project timelines.

• As discussed above, several entities in various industries, including data center and manufacturing, are considering either locating or expanding their operations within Ameren Missouri’s service territory.

In order to address these load growth opportunities, Ameren Missouri expects to file a notice of change in its preferred resource plan with the MoPSC in February 2025.

In order to address these load growth opportunities and ensure reliability, Ameren Missouri filed a notice of change in its September 2023 preferred resource plan with the MoPSC in February 2025.

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 in a safe, reliable, and affordable manner.

Ameren’s goals include both reduction of 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 2025 Change to the 2023 PRP is expected to include, among other things, the following:

• adding 1,600 MWs of natural gas-fired simple-cycle generation by 2030, which includes the 800-MW Castle Bluff Natural Gas Project discussed below, and an additional 1,200 MWs by 2043;

Achieving these goals will be dependent on a variety of factors, including cost-effective advancements in innovative energy technologies and constructive federal and state energy and economic policies.

The 2025 Change to the 2023 PRP includes, among other things, the following:

• estimated total load growth of 1.5 gigawatts by 2032 and 2.5 gigawatts by 2040;

• adding 1,600 MWs of natural gas-fired simple-cycle generation by 2030, which will be achieved through the natural gas generation projects discussed in Note 2 – Rate and Regulatory Matters under Part II, Item 8, of this report, and an additional 1,200 MWs by 2043;

• adding 2,100 MWs of natural gas-fired combined-cycle generation by 2035 and an additional 1,200 MWs by 2040;

• adding 3,200 MWs of renewable generation by 2030, which includes the 900 MWs of solar generation projects discussed in Note 2 – Rate and Regulatory Matters under Part II, Item 8, of this report, and an additional 1,500 MWs by 2035;

• adding 1,000 MWs of battery storage by 2030 and an additional 800 MWs by 2042;

• adding 3,200 MWs of renewable generation by 2030, which includes the solar generation projects discussed in Note 2 – Rate and Regulatory Matters under Part II, Item 8, of this report, and an additional 1,500 MWs by 2035;

• adding 1,000 MWs of battery storage by 2030, which includes the Big Hollow Battery Energy Storage Project discussed in Note 2 – Rate and Regulatory Matters under Part II, Item 8, of this report, and an additional 800 MWs by 2042;

• adding 1,500 MWs of nuclear generation by 2040;

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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, battery storage, or nuclear 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, natural gas-fired, or nuclear 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;

Ameren Missouri’s ability to obtain CCNs from the MoPSC, and any other required state or federal approvals for the addition of renewable resources, battery storage, or nuclear 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, natural gas-fired, or nuclear generation or battery storage and acquire or construct those resources at a reasonable cost;

the ability of suppliers, contractors, and developers to meet contractual commitments and complete projects timely, 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 enter into natural gas supply agreements at reasonable prices and adequate quantities to power Ameren Missouri’s natural gas-fired energy centers;

the continued existence and 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 cost of nuclear generation;

the ability to maintain system reliability during and after the transition to clean energy generation;

the ability to maintain system reliability;

new and/or changes in environmental regulations, including those related to CO 2 and other greenhouse gas emissions;

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and the ability to raise capital on reasonable terms.

The next preferred resource plan is required to be filed by October 2026.

• In October 2024, the MoPSC issued an order approving a nonunanimous stipulation and agreement filed by Ameren Missouri, the MoPSC staff, and other intervenors requesting a CCN for the Castle Bluff Natural Gas Project.

The order also includes the use of a post-construction cost deferral related to the project which allows Ameren Missouri to defer and recover depreciation expense, financing costs, and applicable income taxes incurred from the date the project is placed in service to the date when project costs are reflected in updated base rates as a result of a regulatory rate review.

The period of deferral would be limited to the earlier of the time the project costs are reflected in base rates or six months.

The Castle Bluff Natural Gas Project is aligned with the 2025 Change to the 2023 PRP discussed above, and related expected capital expenditures are included in Ameren’s and Ameren Missouri’s expected capital investments discussed below.

• Through 2029, 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.

Also, changes to capacity accreditation rules adopted by the MISO could reduce the accredited capacity of renewable generation and battery storage and increase regional capacity prices, potentially requiring additional investment and higher costs to satisfy resource adequacy requirements.

In addition, the presidential administration has issued executive orders and taken other actions to increase investment in fossil fuel infrastructure.

This change in federal domestic energy policy has created uncertainty regarding the role existing renewable generation will play in supporting the United States’ energy grid and the timing and extent of future renewable generation infrastructure development.

Ameren Missouri’s plan could be affected by this change in energy policy.

Ameren Missouri expects to file its next preferred resource plan in September 2026.

• Through 2030, 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, as well as generation and battery storage facilities that align with the 2025 Change to the 2023 PRP discussed above.

We estimate that we will invest up to $33.1 billion (Ameren Missouri – up to $22.2 billion;

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These estimates include the MISO long-range transmission projects assigned to Ameren, as well as the first tranche competitive projects awarded to ATXI discussed below.

Ameren’s and Ameren Missouri’s estimates include approximately $1 billion in capital expenditures that may be necessary to comply with regulations issued by the EPA in 2024 relating to CO 2 emissions and MATS, if such regulations are not revised or overturned.

• 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.

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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.

In addition, the MISO awarded three competitive bid projects to ATXI that represent a total estimated investment of approximately $220 million for ATXI.

A decision by the ICC is expected by mid-2025.

In 2024, ATXI filed requests for CCNs, among other things, with the MoPSC related to the MISO long-range transmission projects that it expects to construct within the MoPSC’s jurisdiction.

Decisions by the MoPSC are expected in 2025.

Also in December 2024, the MISO approved a first set of second tranche projects.

Also in 2024, the MISO approved a first set of second tranche projects.

A portion of these projects were assigned to Ameren and are estimated to cost approximately $1.3 billion, based on the MISO’s cost estimate.

The competitive bid process is expected to take place through 2026.

The MISO is assessing future long-range transmission scenarios in the first quarter of 2025 and development of a second set of second tranche projects will follow this assessment.

• Grid reliability, environmental, or other regulations, including those related to CO 2 emissions, or other actions taken by federal or state regulators, could result in significant increases in capital expenditures and operating costs.

The first set of second tranche projects also includes competitive bid projects.

The competitive bid process is expected to continue through 2026.

Separately, in July 2025, the FERC approved transmission rate incentives relating to the second tranche 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.

ATXI will not capitalize allowance for funds used during construction on the related projects.

• In 2025, the presidential administration issued several executive orders on environmental regulations and enforcement.

Many of these actions require further implementation by the EPA, and some of these actions will likely be subject to further judicial review.

Grid reliability, environmental, or other regulations, including those related to CO 2 or other emissions, or other executive orders or actions taken by federal or state regulators, including federal orders related to planned retirements of coal-fired power plants, could result in significant changes in capital expenditures and operating costs.

Regulations can be reviewed and repealed, and replacement or alternative regulations can be proposed or adopted by the regulatory agencies, 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.

See Note 14 – Commitments and Contingencies under Part II, Item 8, of this report, for additional information on environmental matters.

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 operating costs and capital expenditures are subject to MoPSC prudence reviews, which could result in cost disallowances, as well as regulatory lag.

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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 2028, 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.

• The Ameren Companies have multiyear Credit Agreements that cumulatively provide $3.2 billion of credit through December 2030, 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 $4.0 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 2025 to 2029 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, 2024, for Ameren and Ameren Illinois.

See Note 5 – Long-term Debt and Equity Financings under Part II, Item 8, of this report for outstanding forward sale agreements, issuances and maturities of long-term debt through the date of this report, and maturities of long-term debt from 2026 to 2030 and beyond at Ameren (parent), Ameren Missouri, Ameren Illinois, and ATXI.

Ameren (parent) entered into interest rate swaps to hedge a portion of its interest rate risk on cash flows related to certain forecasted debt issuances to occur in 2026 and 2027.

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.