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Item 1A. Risk Factors

2026-02-18 compared with 2025-02-18 · 93 added, 103 removed, 266 unchanged (42% of the section changed)

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and wholesale and retail competition.

In the planning and management of our operations, we must address the effects of existing and proposed laws and regulations and potential changes in our regulatory frameworks, including reinterpretation of such regulations, as well initiatives by federal and state legislatures, RTOs, utility regulators, and taxing authorities, and actions by local jurisdictions that may affect the constructing or siting of facilities.

Significant changes in the nature of the regulation of our businesses, including expiration or discontinuation of, or significant changes to, existing regulatory mechanisms, and the current federal administration’s approach to United States energy policy and resultant changes in regulatory enforcement priorities, and/or evolving interpretations of existing regulatory requirements, could require changes to our business planning, strategy and management of our businesses and could adversely affect our results of operations, financial position, and liquidity.

In the planning and management of our operations, we must address the effects of existing and proposed laws and regulations and potential changes in our regulatory frameworks, including new interpretations of existing regulations, as well as executive orders, initiatives by federal and state legislatures, RTOs, utility regulators, and taxing authorities, and actions by local jurisdictions that may affect the constructing or siting of facilities.

Significant changes in the nature of the regulation of our businesses, including expiration or discontinuation of, or significant changes to, existing regulatory mechanisms, and the presidential administration’s approach to environmental and energy policy and resultant changes in regulatory enforcement priorities, and/or evolving interpretations of existing regulatory requirements, could require changes to our business planning, strategy and management of our businesses and could adversely affect our results of operations, financial position, and liquidity.

Failure to obtain adequate rates or regulatory approvals in a timely manner;

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We are exposed to regulatory lag, including the impact of inflationary pressures, and cost disallowances to varying degrees by jurisdiction, which, if unmitigated, could adversely affect our results of operations, financial position, and liquidity.

Rate orders are also subject to appeal, which creates additional uncertainty as to the rates that we will ultimately be allowed to charge for our services.

Rate orders are also subject to appeal, which creates additional uncertainty as to the rates that we will ultimately be allowed to

charge for our services.

From time to time, our regulators may approve riders or other recovery mechanisms that allow electric or natural gas rates to be adjusted without a traditional regulatory rate review.

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Ameren Missouri’s electric and natural gas utility rates established in those proceedings are based on historical costs, revenues, and sales volumes.

Pursuant to the PPRA, Ameren Missouri’s natural gas utility rates established in proceedings filed after June 2026 will be allowed to be based on future costs, revenues, and sales volumes, subject to MoPSC approval.

Ameren Illinois’ natural gas rates established in those proceedings are based on estimated future costs, revenues, and sales volumes.

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Although rate regulation is premised on providing an opportunity to earn a reasonable rate of return on rate base, there can be no assurance that the regulator will determine that our costs were prudently incurred or that the regulatory process will result in rates that will produce full recovery of such costs or provide for an opportunity to earn a reasonable return on those investments.

Ameren Missouri and Ameren Illinois, and the utility industry generally, have an increased need for cost recovery and to earn a return on investments, primarily driven by capital investments, which is likely to continue in the future.

The resulting increase to the revenue requirement needed to recover such costs and earn a return on investments could result in more frequent regulatory rate reviews and requests for cost recovery mechanisms.

Ameren Missouri and Ameren Illinois, and the utility industry generally, have experienced higher maintenance costs and capital expenditures to operate their electric, natural gas, and transmission businesses, which has led to increases in customer rates and the related revenue requirements needed to recover such costs and earn a return on investments.

This could result in more frequent regulatory rate reviews and requests for cost recovery mechanisms.

Additionally, increasing rates could result in regulatory or legislative actions, as well as competitive or political pressures, all of which could adversely affect our results of operations, financial position, and liquidity.

In addition, in June 2024, the MoPSC issued a financing order authorizing the issuance of securitized utility tariff bonds by a wholly owned, special purpose subsidiary of Ameren Missouri to finance approximately $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 through at least 2027, electric distribution rates for Ameren Illinois are established through an MYRP, which are subject to ongoing regulatory and judicial proceedings and associated risks, and are subject to a reconciliation cap.

Additionally, Ameren Illinois is subject to certain performance metrics that if not achieved would result in a reduction to the company’s allowed ROE.

The CEJA resulted in changes to the regulatory framework applicable to Ameren Illinois’ electric distribution business by giving Ameren Illinois the option to file an MYRP with the ICC or establish rates through a traditional regulatory rate review, among other things.

Beginning in 2024 through at least 2027, electric distribution rates for Ameren Illinois are established through an MYRP, which are subject to ongoing regulatory and judicial proceedings and associated risks, and are subject to a reconciliation cap.

Pursuant to the CEJA, Ameren Illinois has the option to establish electric distribution rates through an MYRP or a traditional regulatory rate review.

An MYRP establishes rates for a four-year period, and Ameren Illinois has the option to file for an MYRP every four years.

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Failure to limit capital expenditures and operation and maintenance expenses to amounts that maintain revenue requirements under the reconciliation cap limit would adversely affect Ameren’s and Ameren Illinois’ results of operations, financial position, and liquidity.

Ameren Illinois’ electric distribution service business is also subject to performance metrics.

Failure to achieve the metrics would result in a reduction in the company’s allowed ROE calculated under the MYRP.

In 2022, the ICC issued an order approving total ROE incentives and penalties of 24 basis points under the MYRP, allocated among seven performance metrics.

These performance metrics include improvements in service reliability in both the frequency and duration of outages, a reduction in peak loads, an increased percentage of

spend with diverse suppliers, a reduction in disconnections for certain customers, and improved timeliness in response to customer requests for interconnection of distributed energy resources.

These performance metrics apply annually from 2024 through 2027 under the MYRP, and the impact of any incentives and penalties will be excluded from the reconciliation cap described above.

In addition, the allowed ROE on energy-efficiency investments can be increased or decreased up to 200 basis points, depending on the achievement of annual energy savings goals.

Any adjustments to the allowed ROE for energy-efficiency investments will depend on annual performance for a historical period relative to energy savings goals.

As a result of the election to use the PISA, Ameren Missouri’s electric service business is subject to a limitation on increasing the annual revenue requirement due to the inclusion of incremental PISA deferrals in the revenue requirement.

Pursuant to a Missouri law, Ameren Missouri’s PISA election was extended through December 2028 and an additional extension through December 2033 is allowed if requested by Ameren Missouri and approved by the MoPSC, among other things.

This law also established a 2.5% 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 limitation is effective for revenue requirements approved by the MoPSC after January 1, 2024.

Pursuant to the PPRA, 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.

Increased capital expenditures could cause incremental PISA deferrals to exceed the 2.25% limitation, and such amounts exceeding the 2.25% limitation would be excluded from recovery under future revenue requirements.

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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.

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

establish siting and land use requirements;

and protect against ecological impacts.

Complex and lengthy processes are required to obtain and renew approvals, permits, and licenses for new, existing, or modified energy-related facilities.

Additionally, the use and handling of various chemicals or hazardous materials require release prevention plans and emergency response procedures.

Additionally, the use and handling of various chemicals and hazardous materials require release prevention plans and emergency response procedures.

Further, we are subject to risks from changing or conflicting interpretations of existing laws, modifications to existing laws, new laws, new or modified permit terms, and enforcement of environmental laws and permits by federal, state, and local authorities.

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Additionally, individuals and non-governmental organizations may seek to enforce environmental laws against us, allege injury from exposure to hazardous materials, allege a failure to comply with environmental laws, seek to compel remediation of environmental contamination, or seek to recover damages resulting from purported contamination.

Environmental regulations have a significant impact on the electric utility industry and compliance with these regulations could be costly for Ameren Missouri, which operates coal-fired and natural gas-fired energy centers.

Environmental regulations impact the electric utility industry, and compliance obligations could be costly for Ameren Missouri, which operates coal-fired and natural gas-fired energy centers.

As of December 31, 2025, Ameren Missouri’s coal-fired energy centers represented 5% and 11% of Ameren’s and Ameren Missouri’s rate base, respectively.

Compliance obligations under the Clean Air Act include the NSPS, the MATS, emission allowance programs and the CSAPR, and the National Ambient Air Quality Standards, which are subject to periodic review for certain pollutants.

Collectively, these regulations cover a variety of pollutants, such as SO 2 , particulate matter, NO x , mercury, toxic metals and acid gases, and CO 2 emissions.

Regulations implementing the Clean Water Act govern potential impacts from our operations on water bodies including wetlands subject to the Act, as well as evaluation of the ecological and biological impact of those operations.

Implementation of the Clean Air Act and the Clean Water Act requirements typically occurs through the issuance of permits by state regulators or resource agencies, and capital expenditures associated with compliance could be significant.

Coal-fired energy centers must comply with management and disposal requirements for coal ash under the Resource Conservation and Recovery Act and federal regulations known as the CCR Rule.

Surface impoundments at Ameren Missouri’s coal-fired energy centers are subject to closure and groundwater monitoring requirements and the implementations of corrective measures if necessary.

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.

In April 2024, the EPA issued a final rule that sets CO 2 emission standards for existing coal-fired and new natural gas-fired power plants based on the emissions expected from adoption of carbon capture technology and/or natural gas co-firing for coal-fired power plants and

carbon capture technology for new natural gas-fired power plants.

Affected power plants are required to comply with the rule through a phased-in approach or retire.

Compliance with the new rule could be required as early as 2030 for certain existing coal-fired power plants and 2032 for certain new natural gas-fired power plants.

In December 2024, the United States Court of Appeals for the District of Columbia Circuit heard arguments from various stakeholders including the EPA, environmental organizations, state attorney generals, and industry groups regarding the legal merits of the final rule.

In February 2025, the EPA requested that the appellate court suspend the case for 60 days and not issue an opinion so the EPA can decide how to proceed.

Ameren and Ameren Missouri estimate capital expenditures of approximately $580 million may be necessary to comply with the final rule assuming it is not revised or overturned.

Ameren and Ameren Missouri are monitoring the legal challenges and assessing the impacts of the final rule and, at this time, cannot predict the final impacts on their results of operations, financial position, and liquidity.

Compliance obligations under the Clean Air Act stem from a variety of programs including the NSPS, the MATS, emission allowance programs, the CSAPR, and the National Ambient Air Quality Standards, which are subject to periodic review for certain pollutants.

Collectively, these regulations cover a variety of pollutants, such as SO 2 , particulate matter, NO x , mercury, toxic metals and acid gases, and CO 2 emissions, although the scope of covered pollutants can change.

To the extent our operations impact surface water bodies, including wetlands, the Clean Water Act requires permitting as well as evaluation of the ecological and biological impact of those operations.

Implementation of requirements under the Clean Air Act and the Clean Water Act typically occurs through the issuance of permits by state regulators or resource agencies, and capital expenditures associated with compliance could be significant.

The management and disposal of coal ash from our coal-fired energy centers must comply with federal regulations known as the CCR Rule issued under the Resource Conservation and Recovery Act and require the closure of surface impoundments at our coal-fired energy centers along with groundwater monitoring requirements and the implementations of corrective measures if necessary.

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.

Currently as required by the CEJA, 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.

Further reductions to emissions limits will become effective between 2030 and 2040, resulting in the possible 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.

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Any of the foregoing could have an adverse effect on our results of operations, financial positions, and liquidity.

We are subject to business and financial risks related to the impact of climate change legislation, regulation, and emission reduction initiatives.

There is concern and activism among various external stakeholders, both nationally and internationally, about climate change, including public concerns about the potential environmental impacts from the combustion of fossil fuels, as well as pressure from public interest groups regarding limiting the use of natural gas.

We are subject to business and financial risks related to the impact of climate-related legislation, regulation, and emission reduction initiatives.

There is concern and activism among various external stakeholders, both nationally and internationally, about climate-related risks, including public concerns about the potential environmental impacts from the combustion of fossil fuels, as well as pressure from public interest groups regarding limiting the use of natural gas.

Also, state and local authorities have proposed restrictions on the use of natural gas, and the ICC is conducting a future of gas proceeding to explore issues involved with decarbonization of the natural gas distribution system in the state of Illinois.

Further, federal, state, and local authorities, including the United States Congress, have considered initiatives to further restrict greenhouse gases to address global climate change, and the EPA previously announced plans to implement new climate change programs, including regulation of greenhouse gas emissions from the utility industry.

Further, federal, state, and local authorities have considered initiatives to further restrict greenhouse gases to address global climate-related risks.

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.

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.

As a result of our diverse fuel portfolio, our emissions of greenhouse gases vary among our energy centers, but coal-fired power plants are significant sources of CO 2 emissions.

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Moreover, to the extent Ameren Missouri requests recovery of these costs through rates, its regulators might deny some or all of, or defer timely recovery of, these costs.

Excessive costs to comply with future legislation or regulations related to climate change might force Ameren Missouri to close its remaining coal-fired energy centers earlier than planned, which could lead to possible loss on abandonment and reduced revenues.

Excessive costs to comply with future legislation or regulations related to climate-related risks might force Ameren Missouri to close its remaining coal-fired energy centers earlier than planned, which could lead to possible loss on abandonment and reduced revenues.

As a result, mandatory limits could have a material adverse impact on Ameren’s and Ameren Missouri’s results of operations, financial position, and liquidity.

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Achievement of these targets is dependent on many factors, including the pace and extent of development and deployment of low- to zero-carbon energy technologies and carbon capture technologies, the cost of those technologies, and support of such technologies by regulators;

natural gas prices;

natural gas and energy prices;

operational performance of low- to zero-carbon resources;

new transmission infrastructure;

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

and constructive energy and economic policies, including those that address investment in energy infrastructure, global climate change, incentives for clean energy technologies, and environmental regulations.

the ability to maintain system reliability;

customer demand for energy including carbon-free energy;

and constructive energy and economic policies, including those that address investment in energy infrastructure, global climate-related risks, incentives for clean energy technologies, and environmental regulations.

Additional factors associated with operational risks for the construction and acquisition of electric and natural gas infrastructure may also affect the achievement of these goals, as further discussed below.

The strategy to achieve these goals also relies on continuing to pursue a diverse portfolio, including low-carbon and carbon-free resources and energy-efficiency resources;

The strategy to achieve these goals also relies on continuing to pursue a diverse portfolio, including low-carbon and carbon-free resources and energy-efficiency resources, while still meeting load growth opportunities;

continuing to participate in efforts to help advance the development of technologies such as carbon capture and sequestration;

the use of hydrogen fuel for electric production and energy storage, next generation nuclear, and large-scale long-cycle battery energy storage;

the use of hydrogen fuel for electric production and energy storage, next generation nuclear, and large-scale long-cycle battery storage;

and constructively engaging with legislators, regulators, investors, customers, and other stakeholders to support outcomes leading to a net-zero future.

We are subject to regulatory compliance and proceedings, which could result in increasing costs, regulatory penalties, and/or other sanctions.

We are subject to FERC regulations, rules, and orders, including standards required by the NERC.

We are subject to FERC regulations, rules, and orders, including standards issued by the NERC.

As owners and operators of bulk power transmission systems and electric energy centers, we are subject to mandatory NERC reliability standards, including cybersecurity standards.

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Compliance with these reliability standards, rules, and regulations may subject us to higher operating costs and may result in increased capital expenditures.

We may also incur higher operating costs to comply with potential new executive orders, regulations, or reinterpretations of existing regulations issued by these regulatory bodies.

We may also incur higher operating costs to comply with potential new executive orders, regulations, or interpretations of existing regulations issued by these regulatory bodies.

If we were found not to be in compliance with these mandatory NERC reliability standards, PHMSA rules and regulations, or FERC regulations, rules, and orders, we could incur substantial monetary penalties and other sanctions, which could adversely affect our results of operations, financial position, and liquidity.

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unsatisfactory performance by the projects when completed;

the inability to earn an adequate return on invested capital;

the ability to raise capital on reasonable terms;

geopolitical conflict and other events beyond our control, including delays arising from government shutdowns or construction delays due to weather.

With respect to the transition of Ameren Missouri’s generation fleet that will be included in its 2025 Change to the 2023 PRP and carbon emission reduction targets, factors also include 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;

With respect to the transition of Ameren Missouri’s generation fleet included in its 2025 Change to the 2023 PRP and carbon emission reduction targets, factors also include 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 to enter into natural gas supply agreements at reasonable prices and adequate quantities to power Ameren Missouri’s natural gas-fired energy centers;

the ability to obtain NRC approval for an extension of the operating license for the Callaway Energy Center beyond its current 2044 expiration date;

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;

energy prices;

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.

Any of these risks could result in higher costs, the inability to complete anticipated projects, or facility closures, and could adversely affect our results of operations, financial position, and liquidity.

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• disruptions in the delivery of electricity and natural gas to our customers;

• disruptions to the global supply chain as a result of shortages for labor, materials, or equipment, tariffs and international trade relations, geopolitical conflict, delivery delays, and economic pressures, including elevated interest rates and inflation, among other things;

• inability to maintain reliability of our electric utility services as coal-fired energy centers are retired and renewable energy generation is placed in service, as well as our ability to meet generation capacity obligations, which could potentially increase if new data centers and/or other large primary service customers locate within our service territories;

• suppliers and contractors who do not perform as required under their contracts, including those obligations that are affected by supply chain disruptions;

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• handling, storage, and disposition of CCR;

• unusual or adverse weather conditions or other natural disasters, including but not limited to those that may result from climate change, such as severe storms, droughts, wildfires, floods, tornadoes, earthquakes, icing, sustained high or low temperatures, solar flares, and electromagnetic pulses;

• unusual or adverse weather conditions or other natural disasters, including but not limited to those that may result from climate-related risks, such as severe storms, droughts, wildfires, floods, tornadoes, earthquakes, icing, sustained high or low temperatures, solar flares, and electromagnetic pulses;

• the level of wind and solar resources;

• inability to operate wind generation facilities at full capacity resulting from requirements to protect natural resources, including wildlife, or other conditions limiting full capacity, such as the 2024 collapse of three turbines at the High Prairie Energy Center;

pending the results of an ongoing investigation, approximately 90% of the turbines of the High Prairie Energy Center remain idle and the timing and costs necessary to return the energy center to full capacity are uncertain;

• the occurrence of catastrophic events such as fires, explosions, acts of sabotage, which have increased in frequency and severity within the utility industry, acts of terrorism, civil unrest, pandemic health events, or other similar events;

• inability to operate wind generation facilities at full capacity resulting from requirements to protect natural resources, including wildlife, or other conditions limiting full capacity;

• the occurrence of catastrophic events such as fires, explosions, acts of sabotage, which in recent years have increased in frequency and severity within the utility industry, acts of terrorism, civil unrest, pandemic health events, or other similar events;

• accidents that might result in injury or loss of life, extensive property damage, or environmental damage;

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• inability to implement or maintain information systems;

• failure to keep pace with and the ability to adapt to rapid technological change;

• failure to keep pace with and the ability to adapt to rapid technological change, including generative and agentic artificial intelligence;

• other unanticipated operations and maintenance expenses and liabilities.

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Ameren Missouri owns and operates coal-fired energy centers.

About 97% of Ameren Missouri’s coal is purchased from the Powder River Basin in Wyoming, which has a limited number of suppliers.

Approximately 96% of Ameren Missouri’s coal is purchased from the Powder River Basin in Wyoming, which has a limited number of suppliers.

Deliveries from the Powder River Basin have occasionally been restricted because of rail congestion, staffing and equipment issues, infrastructure maintenance, derailments, weather, and supplier financial hardship.

As of December 31, 2024, coal inventory at the Labadie and Sioux energy centers were at targeted levels.

As of December 31, 2025, coal inventory was near targeted levels at the Labadie Energy Center and at targeted levels at the Sioux Energy Center.

Delays or disruptions in the delivery of coal, failure of our coal suppliers to provide adequate quantities or quality of coal, or lack of adequate inventories of coal, including low-sulfur coal used to comply with environmental regulations, could have adverse effects on Ameren Missouri’s electric generation operations.

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• costly and extended outages for scheduled or unscheduled maintenance and refueling;

• increased regulatory scrutiny and oversight resulting from more frequent outages;

• uncertainties about the technological and financial aspects of decommissioning nuclear facilities at the end of their licensed lives;

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Both of Ameren Missouri’s coal-fired energy centers were constructed prior to 1978, and the Callaway Energy Center began operating in 1984.

The age of these energy centers increases the risks of unplanned outages, reduced generation output, and higher

maintenance expense.

The age of these energy centers increases the risks of unplanned outages, reduced generation output, and higher maintenance expense.

Further, Ameren Missouri would be adversely affected if the MoPSC does not allow recovery of the remaining investment and decommissioning costs associated with the retirement of an energy center, as well as the ability to earn a return on that remaining investment and those decommissioning costs.

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Any failure to achieve these standards will result in a reduction in Ameren Illinois’ allowed ROE on electric distribution assets.

The higher maintenance costs associated with aging infrastructure and capital expenditures for new or replacement infrastructure, compounded by high interest rates and inflationary pressures, could cause additional rate volatility for our customers, resistance by our regulators to allow customer rate increases, and/or regulatory lag in some of our jurisdictions, any of which could adversely affect our results of operations, financial position, and liquidity.

Forecasted energy demand from potential new customers and electrification might not be realized.

The higher maintenance costs associated with aging infrastructure and capital expenditures for new or replacement infrastructure could cause additional rate volatility and increases for our customers, resistance by our regulators to allow customer rate increases, and/or regulatory lag in some of our jurisdictions, any of which could adversely affect our results of operations, financial position, and liquidity.

Realized energy demand from current and potential new customers may differ significantly from forecasts.

The Ameren Companies have historically experienced minimal growth in energy demand for the past two decades.

However, current industry projections reflect the potential for significant growth in energy demand over the next decade, primarily arising from data centers and further augmented by onshoring and electrification of manufacturing and an increase in transportation electrification.

In addition, in February 2026, Ameren Missouri executed electric service agreements with large load customers under its large load customer rate plan, representing 2.2 gigawatts of demand.

The Ameren Companies may or may not experience the energy demand growth currently being forecasted depending on the decisions of potential new customers about whether to locate their operations within our service territories or whether customers that have signed electric service agreements begin operations within the expected timeframes.

Also, demand growth may not be realized at the rate, or in the amount, expected if construction of customer facilities is not completed within expected timeframes, which is dependent on the ability of suppliers, contractors, and developers to meet contractual commitments and timely complete projects.

In addition, expected demand growth may not be realized if emerging technologies are not broadly adopted at the rate expected, increased efficiencies in computing or other advances in these technologies reduce energy demand for data centers, or large load customers, such as data centers,

are not supported by local communities or do not receive necessary approvals by local municipalities.

Although customers subject to the large load customer rate plan in Ameren Missouri’s service territory are required to sign agreements for specific term lengths to reasonably ensure rates they are charged reflect a representative share of the costs incurred to serve them, these customers could terminate their agreements early or reduce minimum capacity levels.

These agreements include exit fees for early termination and fees for capacity reductions, but these fees may not fully mitigate this risk.

Although assets constructed or acquired to serve these customers will also be used to serve other Ameren Missouri customers, early termination or capacity reductions could impact Ameren Missouri’s ability to fully recover its investment in, and return on, those assets.

Also, the Ameren Companies may not be able to provide the necessary electric service, including both energy and capacity, within the time periods required by large load customers.

The Ameren Companies may need to accelerate the addition of generation resources within current plans, obtain new generation resources, expand transmission or distribution facilities that are not currently within their plans, or purchase additional energy and capacity to meet the increase in demand.

In addition, demand for construction services within the utility industry has increased significantly due to growing energy demand and energy transition, creating limited availability of suppliers, contractors, and developers, which could impact the Ameren Companies' ability to timely construct or acquire assets needed to meet forecasted demand.

If the Ameren Companies are required to purchase energy and capacity to meet demand, their risk management and liquidity levels may not be effective at mitigating price impacts of such purchases, or there may not be sufficient energy and capacity available, either of which could negatively impact the Ameren Companies’ ability to realize forecasted or other potential demand.

The Ameren Companies may not be able to plan, receive regulatory approvals, and execute those plans in a timely manner, which could result in the Ameren Companies not realizing forecasted or other potential demand.

Energy conservation, energy efficiency, distributed generation, energy storage, technological advances, and other factors could reduce energy demand from our existing customers.

The Ameren Companies have experienced minimal growth in energy demand for the past two decades.

Recent industry projections reflect the potential for significant growth in energy demand over the next decade, primarily arising from data centers to support artificial intelligence and further augmented by onshoring and electrification of manufacturing and an increase in transportation electrification.

The Ameren Companies may or may not experience energy demand growth depending on the decisions of potential new customers about whether to locate their operations within our service territories.

If new customers elect to locate operations within our service territories, the Ameren Companies may not be able to provide the necessary electric service within the time periods required by those customers.

The Ameren Companies may need to accelerate new generation build within current plans, and construct or obtain new generation sources and expand transmission and distribution facilities that are not currently within their plans.

The Ameren Companies may not be able to plan, receive regulatory approvals, and execute those plans in a timely manner.

Future demand from these customers may not be realized at the current projected pace as a result of increased efficiency in computing, and these new customers may be transitory and exit our service territory.

Significant uncertainty exists regarding future increases in energy demand within the Ameren Companies’ service territory, and whether and how the Ameren Companies will construct or obtain the assets necessary to timely serve that additional demand.

Without a regulatory mechanism to ensure recovery, declines in energy usage could result in an under-recovery of our revenue requirement or an increase in our customer rates, as the revenue requirement would be spread over less sales volumes, which could adversely affect our results of operations, financial position, and liquidity.

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• energy-efficiency efforts by customers not related to our energy-efficiency programs;

• technological advancements that reduce energy consumption and demand;

• increased customer use of distributed generation sources, such as solar panels and other technologies, which have become more cost-competitive, with decreasing costs expected in the future, as well as the use of energy storage technologies;

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Ameren’s subsidiaries are separate and distinct legal entities and have no obligation, contingent or otherwise, to pay any dividends or make any other distributions (except for payments required pursuant to the terms of affiliate borrowing arrangements and cash payments under the tax allocation agreement) to Ameren.

Under the IRA, a 15% minimum tax on adjusted financial statement income, as defined in the law, is assessed against corporations whose average annual adjusted financial statement income exceeds $1 billion for three consecutive preceding tax years effective for tax years beginning after December 31, 2022.

Once a corporation exceeds this three-year average annual adjusted financial statement income threshold, it will be subject to the minimum tax for all future tax years.

As Ameren files a consolidated income tax return, it is reliant on its subsidiaries to pay the minimum tax once the threshold is exceeded.

The payments related to the minimum tax by Ameren

Missouri, Ameren Illinois, and ATXI are expected to be recovered, subject to approval by their respective regulators.

As Ameren is a holding company and files a consolidated income tax return, it is reliant on its subsidiaries to pay the minimum tax once the threshold is exceeded.

The payments related to the minimum tax by Ameren Missouri, Ameren Illinois, and ATXI are expected to be recovered, subject to approval by their respective regulators.

In addition, interpretations, regulations, amendments, or technical corrections that affect the amount and timing of income tax payments, credits available, or the transferability of production and investment tax credits could adversely affect our liquidity.

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Significant increases in prices of labor, services, materials and supplies and other costs, including costs associated with our defined benefit retirement and postretirement plans, health care plans, and other employee benefits, could adversely affect our results of operations, financial position, or liquidity.

A part of our core strategy focuses on disciplined cost management, including prudently monitoring all of our expenses.

Higher than expected inflation levels could continue to put pressure on the prices of labor, services, materials and supplies, and other costs.

Elevated inflation levels, as well as elevated interest rates, tariffs, trade wars, or a recession could impact our ability to control costs, to make substantial investments in our businesses, to recover costs and investments, to earn our allowed ROEs within frameworks established by our regulators, and/or to maintain affordability of our services for our customers.

A part of our strategy focuses on disciplined cost management, including prudently monitoring all of our expenses.

Higher than expected inflation levels could put pressure on the prices of labor, services, materials and supplies, and other costs.

Higher inflation levels, as well as higher interest rates, tariffs, trade wars, or a recession could impact our ability to control costs, to make substantial investments in our businesses, to recover costs and investments, to earn our allowed ROEs within frameworks established by our regulators, and/or to maintain affordability of our services for our customers.

In addition, these various economic pressures could adversely affect our customers’ usage of, or payment for, our services.

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Ameren expects to fund its pension plans at a level equal to the greater of the pension cost or the legally required minimum contribution.

Based on its assumptions at December 31, 2024, its investment performance in 2024, and its pension funding policy, Ameren does not expect to make material contributions in 2025 and expects to make aggregate contributions of $170 million in 2026 through 2029.

Based on its assumptions at December 31, 2025, its investment performance in 2025, and its pension funding policy, Ameren expects to make annual contributions of approximately $45 million to $50 million in each of the next five years, with aggregate estimated contributions of $240 million .

Ameren Missouri and Ameren Illinois estimate that their portion of the future funding requirements will be 35% and 45%, respectively.

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The level of rates, the timing and magnitude of rate increases, and the volatility of rates can also affect regulator and customer satisfaction.

Our ability to successfully execute our strategic plan, including the transition of Ameren Missouri’s generation fleet that will be included in its 2025 Change to the 2023 PRP, may affect customers’, investors’, legislators’, regulators’, creditors’, and rating agencies’ opinions and actions.

In addition, rising energy and capacity prices, which are largely outside of our control, could impact customer affordability and satisfaction.

Ameren Missouri’s and Ameren Illinois’ recent electric and natural gas regulatory rate reviews have resulted in increases in rates charged to customers which had an adverse impact on customer satisfaction and increased political pressures and media attention.

Our ability to successfully execute our strategic plan, including the transition of Ameren Missouri’s generation fleet included in its 2025 Change to the 2023 PRP, may affect customers’, investors’, legislators’, regulators’, creditors’, and rating agencies’ opinions and actions.

Additionally, negative perceptions or publicity resulting from increasing scrutiny of company policies or practices could negatively impact our reputation, investment in our common stock, or our access to capital and credit markets.

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Additionally, negative opinions about us or other utility companies could make it more difficult for our businesses to achieve favorable legislative or regulatory outcomes.

Negative opinions could also result in sales volume reductions or

increased use of distributed generation by our customers.

Negative opinions could also result in sales volume reductions or increased use of distributed generation by our customers.

Any of these consequences could adversely affect our results of operations, financial position, and liquidity.

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The Ameren Illinois collective bargaining unit contracts expire in 2027 and 2029, and cover 8% and 92% of represented employees, respectively.

Ameren Missouri and Ameren Illinois expect to renew these contracts prior to their expiration, however there can be no guarantee that such renewals will be secured on favorable terms.

Certain events, such as significant delays in finding appropriate replacement talent, inadequately trained replacement employees, a mismatch of skill sets to future needs, or any work stoppage experienced in connection with negotiations of collective bargaining agreements could adversely affect our operations.

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Physical attacks could include sabotaging, vandalizing, or burglarizing transmission and distribution facilities, which are unmanned, widely dispersed, and often in isolated areas, or the theft of physical data and information.

Cyber attacks could include viruses, malicious or destructive code, phishing or quishing attacks, denial of service attacks, supply chain attacks, ransomware and other extortion-based attacks, improper access by third parties, attacks on email systems, and attacks leading to data loss, operational control, or exploitation of vulnerabilities specific to internally developed systems or to those provided and/or maintained by our suppliers, including those attacks arising from or generated by artificial intelligence, among various other security breaches.

In addition, the increasingly widespread adoption of artificial intelligence technologies, including generative artificial intelligence, may increase cyber attacks and other operational, legal, privacy, and reputational risks in our industry and worldwide.

Cyber attacks could include viruses, malicious or destructive code, social engineering attacks, denial of service attacks, supply chain attacks, ransomware and other extortion-based attacks, improper access by third parties, attacks on email systems, and attacks leading to data loss, including data stored using cloud technologies, operational control, or exploitation of vulnerabilities specific to internally developed systems or to those provided and/or maintained by our suppliers.

This also includes attacks arising from or generated by artificial intelligence, among various other attempts to compromise systems that can lead to security breaches.

In addition, the increasingly widespread adoption of artificial intelligence technologies, including generative and agentic artificial intelligence, may increase, accelerate, or enhance cyber attacks and other operational, legal, privacy, and reputational risks in our industry and worldwide.

Also, remote working arrangements could increase our data security risks, including loss of data related to sensitive customer, employee, financial, and operating system information, through insider or outsider actions.

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General economic factors beyond our control might create uncertainty that could increase our cost of capital or impair or eliminate our ability to access the debt, equity, or credit markets, including our ability to draw on bank credit facilities.

These factors include depressed economic conditions, a recession,

increasing interest rates, inflation, sanctions, trade restrictions, tariffs or trade wars, political instability, war, terrorism, and extreme volatility in the debt, equity, or credit markets.

These factors include depressed economic conditions, a recession, increasing interest rates, inflation, sanctions, trade restrictions, tariffs or trade wars, government or federal agency shutdowns, political

instability, war, terrorism, and extreme volatility in the debt, equity, or credit markets.

In addition, volatility in stock prices of perceived significant energy consumers, such as technology companies involved with artificial intelligence or cryptocurrency, or other significant developments with such companies, could cause increased volatility in stock prices of energy utility companies such as Ameren.

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Compared sentence by sentence after normalising whitespace, quotation marks, case and digits, so re-formatting and restated figures do not read as changed language. Wording changes appear as one removal and one addition. The current filing and the prior one are authoritative.

What changed 10-K

Item 1A. Risk Factors