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What changed in Ameren's 10-K — 2024 vs 2025

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Paragraph-level year-over-year comparison of Ameren's 2024 and 2025 10-K annual filings, covering the Business, Risk Factors, Legal Proceedings, Cybersecurity, MD&A and Market Risk sections. Every new, removed and edited paragraph is highlighted side-by-side so you can see exactly what management changed in the 2025 report.

+590 added−615 removedSource: 10-K (2026-02-18) vs 10-K (2025-02-18)

Top changes in Ameren's 2025 10-K

590 paragraphs added · 615 removed · 424 edited across 9 sections

Item 1. Business

Business — how the company describes what it does

78 edited+31 added−21 removed50 unchanged
Biggest changeThese issues include: • the potential for changes in laws, regulations, enforcement efforts, and policies at the federal, state, and international levels, including but not limited to, complex new and proposed environmental laws, such as air and water quality standards, mercury emissions standards, limitations on the use of natural gas in generation, CCR management requirements, and potential CO 2 limitations, which may limit, or result in the cessation of, the operation of electric generating units; • corporate tax law changes, including the IRA, as well as additional interpretations, regulations, amendments, or technical corrections that affect the amount and timing of income tax payments or the transferability of production and investment tax credits, reduce or limit the ability to claim certain deductions and use carryforward tax benefits and/or credits, or result in rate base reductions; • cybersecurity risks, cyber attacks, including ransomware and other ransom-based attacks and those attacks arising from or generated by artificial intelligence, hacking, social engineering, and other forms of malicious cybersecurity and/or privacy events, which could result in the loss of operational control of energy centers and electric and natural gas transmission and distribution systems and/or the theft or inappropriate release of certain types of information, including sensitive customer, employee, financial, and operating system information; • acts of sabotage, which have increased in frequency and severity within the utility industry, terrorism, and other intentionally disruptive acts; • political, regulatory, and customer resistance to higher rates; • the impacts from new data centers expected to be constructed over the next several years, including increased competition among utilities, independent power producers and non-traditional market entrants, providing generation and resource adequacy to support the projected load growth, and managing the impact on customer rates; • the impact and effectiveness of vegetation management programs; • the potential for reliability issues due to inadequate resources resulting from the retirement of fossil-fuel-fired generation facilities as they are replaced with renewable energy generation sources, increasing load growth, and market inefficiencies related to prices for purchased power, capacity, and ancillary services, and other factors; • the need to place new transmission and generation facilities in service, which is dependent upon timely regulatory approvals and the availability of necessary labor and materials, among other things, to maintain grid reliability; • pressure and uncertainty on customer growth and sales volumes in light of increased competition in the industry and economic conditions; 16 Table of Contents • the ability to recover and earn a fair return on investments due to changes in the allowed ROE, including ROE incentive adders on FERC-regulated electric transmission assets; • the influence of macroeconomic factors on yields of United States Treasury securities and on the allowed ROE provided by regulators; • regulatory lag; • the availability of fuel, materials and supplies, and equipment, and the potential disruptions in supply chains and inflationary pressures or tariffs on the prices and availability of commodities, labor, services, materials and supplies, elevated interest rates, and impacts associated with extended recovery periods from customers; • the availability of a skilled work force, including transferring the specialized knowledge of those who are nearing retirement to employees succeeding them; • maintaining affordability of electric and natural gas utility services for customers, including the demand for access to renewable energy generation at rates acceptable to customers; • the modernization of the electric grid to accommodate a two-way flow of electricity and increased capacity for distributed generation interconnection; • net metering rules and other changes in existing regulatory frameworks and recovery mechanisms to address the allocation of costs to customers who own generation resources that enable them both to sell power to us and to purchase power from us through the use of our transmission and distribution assets; • legislation or programs to encourage or mandate energy efficiency, energy conservation, and renewable sources of power, and the lack of consensus as to how those programs should be paid for; • higher levels of infrastructure and technology investments and adjustments to customer rates associated with the refund of excess deferred income taxes that have resulted in, and are expected to continue to result in, negative or decreased free cash flow, which is defined as cash flows from operating activities less cash flows from investing activities and dividends paid; • public concerns about the siting of new facilities, and challenges that members of the public can assert against applications for governmental permits and other approvals required to site and build new facilities that can result in significant cost increases, delays and denial of the permits and approvals by the regulators; • public concerns about the potential environmental impacts from the combustion of fossil fuels; • pressure from public interest groups regarding limiting the use of natural gas, as well as proposed restrictions on the use of natural gas by state and local authorities; • certain investors’ concerns about investing in, as well as certain insurers’ concerns about providing coverage to, utility companies that have coal-fired generation assets; • scrutiny by investors and other stakeholders of industry practices; • public concerns about nuclear decommissioning and the disposal of nuclear waste; • industry challenges resulting from alleged or actual legal, regulatory or compliance failures, including in connection with lobbying and political activities or liabilities arising out of wildfires or other catastrophic events; and • effects of mergers, acquisitions, and divestitures within the utility industry.
Biggest changeThese issues include: • the potential for changes in laws, regulations, enforcement efforts, and policies at the federal, state, and international levels, including but not limited to environmental laws and the presidential administration’s change in federal domestic energy policy to support investments in fossil fuel infrastructure and the effect it may have on the ability to construct and/or acquire renewable energy generation facilities and battery storage; • corporate tax law changes, including the OBBBA and the IRA, as well as additional interpretations, regulations, amendments, or technical corrections that affect the amount and timing of income tax payments or the transferability of production and investment tax credits, reduce or limit the ability to claim certain deductions and use carryforward tax benefits and/or credits, or result in rate base reductions; • maintaining affordability of electric and natural gas utility services for customers, including the demand for access to renewable energy generation, at rates acceptable to customers; • political, regulatory, and customer resistance to higher rates; • cybersecurity risks, cyber attacks, including ransomware and other ransom-based attacks and those attacks arising from or generated by generative or agentic artificial intelligence, hacking, social engineering, and other forms of malicious cybersecurity and/or privacy events, which could result in the loss of operational control of energy centers and electric and natural gas transmission and distribution systems and/or the theft or inappropriate release of certain types of information, including sensitive customer, employee, financial, and operating system information; • acts of sabotage, which in recent years have increased in frequency and severity within the utility industry, terrorism, and other intentionally disruptive acts; • the impacts from new data centers expected to be constructed over the next several years, including increased competition among utilities, independent power producers and non-traditional market entrants, providing generation and resource adequacy to support the projected load growth, managing the impact on customer rates, and the possibility that future demand from data centers may not be realized at the current projected pace; • pressure and uncertainty on customer growth and sales volumes in light of increased competition in the industry and economic conditions; • the impact and effectiveness of vegetation management programs; • the potential for reliability issues due to inadequate resources resulting from the retirement of fossil-fuel-fired generation facilities as they are replaced with renewable energy generation sources, increasing load growth, and market inefficiencies related to prices for purchased power, capacity, and ancillary services, and other factors; • the need to place new transmission and generation facilities in service, which is dependent upon timely regulatory approvals and the availability of necessary labor and materials, among other things, to maintain grid reliability; • the ability to recover and earn a fair return on investments due to changes in the allowed ROE, including ROE incentive adders on FERC-regulated electric transmission assets; • the influence of macroeconomic factors on yields of United States Treasury securities and on the allowed ROE provided by regulators; • regulatory lag; • the availability of fuel, materials and supplies, and equipment, and the potential disruptions in supply chains and inflationary pressures or tariffs on the prices and availability of commodities, labor, services, materials and supplies, and impacts associated with extended recovery periods from customers; • the availability of a skilled work force, including transferring the specialized knowledge of those who are nearing retirement to employees succeeding them; • the modernization of the electric grid to accommodate a two-way flow of electricity and increased capacity for distributed generation interconnection; • net metering rules and other changes in existing regulatory frameworks and recovery mechanisms to address the allocation of costs to customers who own generation resources that enable them both to sell power to us and to purchase power from us through the use of our transmission and distribution assets; • legislation or programs to encourage or mandate energy efficiency, energy conservation, and renewable sources of power, and the lack of consensus as to how those programs should be paid for; 17 Table of Contents • higher levels of infrastructure and technology investments and adjustments to customer rates associated with the refund of excess deferred income taxes that have resulted in, and are expected to continue to result in, negative or decreased free cash flow, which is defined as cash flows from operating activities less cash flows from investing activities and dividends paid; • public concerns about the siting of new facilities, and challenges that members of the public can assert against applications for governmental permits and other approvals required to site and build new facilities that can result in significant cost increases, delays and denial of the permits and approvals by the regulators; • public concerns about the potential environmental impacts from the combustion of fossil fuels; • pressure from public interest groups regarding limiting the use of natural gas, as well as proposed restrictions on the use of natural gas by state and local authorities; • certain investors’ concerns about investing in, as well as certain insurers’ concerns about providing coverage to, utility companies that have coal-fired generation assets; • scrutiny by investors and other stakeholders of industry practices; • public concerns about nuclear energy and the disposal of nuclear waste; • industry challenges resulting from alleged or actual legal, regulatory, or compliance failures, including in connection with lobbying and political activities or liabilities arising out of wildfires or other catastrophic events; and • effects of mergers, acquisitions, and divestitures within the utility industry.
The need for investment in new sources of energy is dependent on several key factors, including continuation of and customer participation in energy-efficiency programs, the amount of distributed generation from customers, load growth, including demand from data centers, technological advancements, costs of generation alternatives, environmental regulation of coal-fired and natural gas-fired power plants, changes in United States energy policy and priorities under the current federal administration, and state renewable energy requirements, which could lead to the retirement of current baseload assets before the end of their current useful lives or alterations in the way those assets operate, which could result in increased capital expenditures and/or increased operations and maintenance expenses.
The need for investment in new sources of energy is dependent on several key factors, including continuation of and customer participation in energy-efficiency programs, the amount of distributed generation from customers, load growth, including demand from data centers, technological advancements, costs of generation alternatives, environmental regulation of coal-fired and natural gas-fired power plants, changes in United States energy policy and priorities under the presidential administration, and state renewable energy requirements, which could lead to the retirement of current baseload assets before the end of their current useful lives or alterations in the way those assets operate, which could result in increased capital expenditures and/or increased operations and maintenance expenses.
Based on IPA procurement events that align with the IPA’s plan, Ameren Illinois has contractual commitments to purchase approximately 1.6 million wind renewable energy credits per year and approximately 3.6 million solar renewable energy credits per year. Ameren Illinois has also entered into contracts, ending in 2032, to purchase approximately 0.6 million wind renewable energy credits per year.
Based on IPA procurement events that align with the IPA’s plan, Ameren Illinois has contractual commitments to purchase approximately 3.1 million wind renewable energy credits per year and approximately 4.1 million solar renewable energy credits per year. Ameren Illinois has also entered into contracts, ending in 2032, to purchase approximately 0.6 million wind renewable energy credits per year.
Ameren Illinois’ electric energy-efficiency investments are deferred as a regulatory asset and earn a return at the applicable WACC, with the ROE based on the annual average of the monthly yields of the 30-year United States Treasury bonds plus 580 basis points.
Ameren Illinois’ electric energy-efficiency investments are deferred as a regulatory asset and earn a return at the applicable WACC, with the ROE currently based on the annual average of the monthly yields of the 30-year United States Treasury bonds plus 580 basis points.
Ameren Missouri and Ameren Illinois primarily use Panhandle Eastern Pipe Line Company, Trunkline Gas Company, Natural Gas Pipeline Company of America, Mississippi River Transmission Corporation, Northern Border Pipeline Company, MoGas Pipeline, and Texas Eastern Transmission Corporation interstate pipeline systems to transport natural gas to their systems.
Ameren Missouri and Ameren Illinois primarily use Panhandle Eastern Pipe Line Company, Trunkline Gas Company, Natural Gas Pipeline Company of America, Mississippi River Transmission Corporation, Northern Border Pipeline Company, Spire MoGas Pipeline, and Texas Eastern Transmission Corporation interstate pipeline systems to transport natural gas to their systems.
As of December 31, 2024, Ameren Missouri and Ameren Illinois have completed the transition to smart meters, which have been installed for nearly all electric and natural gas customers. Ameren Missouri In Missouri, the Missouri Energy Efficiency Investment Act established a rider that, among other things, allows electric utilities to recover costs with respect to MoPSC-approved customer energy-efficiency programs.
As of December 31, 2025, Ameren Missouri and Ameren Illinois have completed the transition to smart meters, which have been installed for nearly all electric and natural gas customers. Ameren Missouri In Missouri, the Missouri Energy Efficiency Investment Act established a rider that, among other things, allows electric utilities to recover costs with respect to MoPSC-approved customer energy-efficiency programs.
Pursuant to the CEJA, Ameren Illinois is required to file a Grid Plan with the ICC every four years. In December 2024, the ICC issued an order approving Ameren Illinois’ revised Grid Plan under its MYRP proceeding for electric distribution service for 2024 through 2027.
Pursuant to Illinois law, Ameren Illinois is required to file a Grid Plan with the ICC every four years. In December 2024, the ICC issued an order approving Ameren Illinois’ revised Grid Plan under its MYRP proceeding for electric distribution service for 2024 through 2027.
Ameren Missouri expects to satisfy the requirement in 2025 with its High Prairie, Atchison, Huck Finn, Keokuk, Maryland Heights, and other solar energy centers, along with other renewable energy credits purchased by Ameren Missouri, including solar-generated renewable energy credits purchased from customer-installed systems.
Ameren Missouri expects to satisfy the requirement in 2026 with its High Prairie, Atchison, Huck Finn, Keokuk, Maryland Heights, and other solar energy centers, along with other renewable energy credits purchased by Ameren Missouri, including solar-generated renewable energy credits purchased from customer-installed systems.
For information regarding the percentage of Ameren Missouri’s and Ameren Illinois’ projected remaining natural gas supply requirements that are price-hedged through 2029, see Commodity Price Risk under Part II, Item 7A, of this report.
For information regarding the percentage of Ameren Missouri’s and Ameren Illinois’ projected remaining natural gas supply requirements that are price-hedged through 2031, see Commodity Price Risk under Part II, Item 7A, of this report.
Under an MYRP, Ameren Illinois will reconcile its actual revenue requirement, as adjusted for certain cost variations, to ICC-approved electric distribution service rates on an annual basis, subject to a reconciliation cap. The reconciliation cap limits the annual adjustment to 105% of the annual revenue requirement approved by the ICC.
Under the MYRP, Ameren Illinois reconciles its actual revenue requirement, as adjusted for certain cost variations, to ICC-approved electric distribution service rates on an annual basis, subject to a reconciliation cap. The reconciliation cap limits the annual adjustment to 105% of the annual revenue requirement approved by the ICC.
Ameren Missouri’s Keokuk Energy Center and its dam on the Mississippi River between Hamilton, Illinois, and Keokuk, Iowa, 9 Table of Contents are operated under authority granted by an Act of Congress in 1905. The Keokuk Energy Center dam safety program is regulated by the Illinois Department of Natural Resources.
Ameren Missouri’s Keokuk Energy Center and its dam on the Mississippi River between Hamilton, Illinois, and Keokuk, Iowa, are operated under authority granted by an Act of Congress in 1905. The Keokuk Energy Center dam safety program is regulated by the Illinois Department of Natural Resources.
Ameren Illinois In accordance with Illinois law, Ameren Illinois is required to collect funds from all electric distribution customers to fund IPA procurement events for renewable energy credits. The amount set by law and required to be collected from customers by Ameren Illinois is capped at $4.58 per MWh.
Ameren Illinois In accordance with Illinois law, Ameren Illinois is required to collect funds from all electric distribution customers to fund IPA procurement events for renewable energy credits. The amount set by law and required to be collected from customers by Ameren Illinois is currently $4.58 per MWh.
Ameren Missouri has inventories and supply contracts sufficient to meet all of its uranium (concentrate and hexafluoride), conversion, enrichment, and fabrication requirements at least through the spring 2028 refueling. Renewable Ameren Missouri operates several renewable energy centers, which includes hydroelectric, wind, methane gas, and solar energy centers. The High Prairie and Atchison energy centers are wind generation facilities.
Ameren Missouri has inventories and supply contracts sufficient to meet all of its uranium (concentrate and hexafluoride), conversion, enrichment, and fabrication requirements at least through the fall 2029 refueling. Renewable Ameren Missouri operates several renewable energy centers, which includes hydroelectric, wind, methane gas, and solar energy centers. The High Prairie and Atchison energy centers are wind generation facilities.
Power purchased by Ameren Illinois for its electric distribution customers who do not elect to purchase their power from an alternative retail electric supplier comes either through procurement processes conducted by the IPA or through markets operated by the MISO. The IPA administers an RFP process through which Ameren Illinois procures its expected supply.
Power purchased by Ameren Illinois for its electric distribution customers who do not elect to purchase their power from an alternative retail electric supplier comes either through procurement processes conducted by the IPA or through markets operated by the MISO. The IPA administers an RFP process through which Ameren Illinois procures its expected 11 Table of Contents supply.
The MEEIA rider allows Ameren Missouri to collect from customers its actual program costs, lost electric revenues, and any performance incentive, without a traditional regulatory rate review, subject to MoPSC prudence reviews, until lower volumes resulting from 13 Table of Contents the MEEIA programs are reflected in base rates.
The MEEIA rider allows Ameren Missouri to collect from customers its actual program costs, lost electric revenues, and any performance incentive, without a traditional regulatory rate review, subject to MoPSC prudence reviews, until lower volumes resulting from the MEEIA programs are reflected in base rates.
In 2024, 2023, and 2022, Ameren Illinois procured power on behalf of its customers for 25%, 28%, and 28%, respectively, of its total kilowatthour sales.
In 2025, 2024, and 2023, Ameren Illinois procured power on behalf of its customers for 28%, 25%, and 28%, respectively, of its total kilowatthour sales.
In addition to reviewing and determining the Ameren Companies’ 14 Table of Contents compensation practices and policies for the chief executive officer and other executive officers, the Human Resources Committee of Ameren’s board of directors is responsible for oversight of Ameren’s human capital management practices and policies.
In addition to reviewing and determining the Ameren Companies’ compensation practices and policies for the Chief Executive Officer and other executive officers, the Human Resources Committee of Ameren’s board of directors is responsible for oversight of Ameren’s human capital management practices and policies.
Federal and state authorities periodically review and modify existing regulations and adopt new regulations, which may impact our planning process and the ultimate implementation of these or other new or revised regulations. Recent and potential new executive orders issued by the current federal administration as well as local and state land use requirements can also impact our planning activities.
Federal and state authorities periodically review and modify existing regulations and adopt new regulations, which may impact our planning process and the ultimate implementation of these or other new or revised regulations. Executive orders issued by the presidential administration as well as local and state land use requirements can also impact our planning activities.
The AMIL balancing authority area includes the load of Ameren Illinois and certain Ameren Missouri energy centers located in Illinois, and had a peak demand of 8,479 MWs in 2024. The Ameren transmission system directly connects with 15 other balancing authority areas for the exchange of electric energy. Ameren Missouri, Ameren Illinois, and ATXI are transmission-owning members of the MISO.
The AMIL balancing authority area includes the load of Ameren Illinois and certain Ameren Missouri energy centers located in Illinois, and had a peak demand of 8,027 MWs in 2025. The Ameren transmission system directly connects with 15 other balancing authority areas for the exchange of electric energy. Ameren Missouri, Ameren Illinois, and ATXI are transmission-owning members of the MISO.
TRANSMISSION Ameren owns an integrated transmission system that is composed of the transmission assets of Ameren Missouri, Ameren Illinois, and ATXI. Ameren also operates two MISO balancing authority areas: AMMO and AMIL. The AMMO balancing authority area includes the load and most energy centers of Ameren Missouri, and had a peak demand of 7,560 MWs in 2024.
TRANSMISSION Ameren owns an integrated transmission system that is composed of the transmission assets of Ameren Missouri, Ameren Illinois, and ATXI. Ameren also operates two MISO balancing authority areas: AMMO and AMIL. The AMMO balancing authority area includes the load and most energy centers of Ameren Missouri, and had a peak demand of 7,487 MWs in 2025.
Steps include evaluating the potential for further diversification of Ameren Missouri’s generation portfolio through renewable energy generation, including wind and solar generation, natural gas-fired generation, including the potential to switch to hydrogen fuel and/or blend hydrogen fuel with natural gas and install carbon capture technology, extending the operating license for the Callaway Energy Center, additional customer energy-efficiency and demand response programs, distributed energy resources, and energy storage.
Steps include evaluating the potential for further diversification of Ameren Missouri’s generation portfolio through renewable energy generation, including wind and solar generation, natural gas-fired generation, including the potential to blend hydrogen fuel with natural gas and install carbon capture technology, extending the operating license for the Callaway Energy Center, adding new nuclear generation, additional customer energy-efficiency and demand response programs, distributed energy resources, and energy storage.
Ameren Missouri expects to file a notice of change in its preferred resource plan with the MoPSC in February 2025 to address new load growth opportunities resulting from entities in various industries, including data center and manufacturing, that are considering either locating or expanding their operations within Ameren Missouri’s service territory.
Ameren Missouri filed a notice of change in its September 2023 preferred resource plan with the MoPSC in February 2025 to address new load growth opportunities resulting from entities in various industries, including data center and manufacturing, that are considering either locating or expanding their operations within Ameren Missouri’s service territory.
The Ameren Missouri collective bargaining unit contracts expire in 2025 and 2026, and cover 4% and 96% of represented employees, respectively. The Ameren Illinois collective bargaining unit contracts expire in 2026 and 2027, and cover 92% and 8% of represented employees, respectively.
The Ameren Missouri collective bargaining unit contracts expire in 2026 and 2028, and cover 96% and 4% of represented employees, respectively. The Ameren Illinois collective bargaining unit contracts expire in 2027 and 2029, and cover 8% and 92% of represented employees, respectively.
For information regarding the percentages of Ameren Missouri’s projected required supply of coal and coal transportation that are price-hedged through 2029, see Commodity Price Risk under Part II, Item 7A, of this report. About 97% of Ameren Missouri’s coal is purchased from the Powder River Basin in Wyoming, which has a limited number of suppliers.
For information regarding the percentages of Ameren Missouri’s projected required supply of coal and coal transportation that are price-hedged through 2030, see Commodity Price Risk under Part II, Item 7A, of this report. Approximately 96% of Ameren Missouri’s coal is purchased from the Powder River Basin in Wyoming, which has a limited number of suppliers.
Both of Ameren Missouri’s coal-fired energy centers were constructed prior to 1978. As of December 31, 2024, Ameren Missouri’s coal-fired energy centers represented 6% and 11% of Ameren’s and Ameren Missouri’s rate base, respectively. The Callaway Energy Center began operation in 1984 and is licensed to operate until 2044.
Both of Ameren Missouri’s coal-fired energy centers were constructed prior to 1978. 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. The Callaway Energy Center began operation in 1984 and is currently licensed to operate until 2044.
Ameren Missouri has entered into uranium, uranium conversion, uranium enrichment, and fabrication contracts to procure the fuel supply for its Callaway Energy Center. The Callaway Energy Center requires refueling at 18-month intervals. The last refueling was completed in November 2023. The next refueling is scheduled for the spring of 2025.
Ameren Missouri has entered into uranium, uranium conversion, uranium enrichment, and fabrication contracts to procure the fuel supply for its Callaway Energy Center. The Callaway Energy Center requires refueling at 18-month intervals. The last refueling was completed in July 2025. The next refueling is scheduled for the fall of 2026.
Ameren Missouri and Ameren Illinois satisfied their renewable energy portfolio requirements in 2024, pending regulatory review by the MoPSC for Ameren Missouri. 12 Table of Contents Ameren Missouri In Missouri, utilities are required to purchase or generate electricity equal to at least 15% of native load sales from renewable energy sources, with at least 2% of the requirement derived from solar energy.
Ameren Missouri and Ameren Illinois satisfied their renewable energy resource requirements in 2025, pending regulatory review by the MoPSC for Ameren Missouri. Ameren Missouri In Missouri, utilities are required to purchase or generate electricity equal to at least 15% of native load sales from renewable energy sources, with at least 2% of the requirement derived from solar energy.
In addition to base salary, medical benefits, and retirement benefits, including pension for substantially all employees and 401(k) savings, our total rewards package includes short-term incentives and long-term stock-based compensation for certain employees. Further, we offer our employees various programs that encourage overall well-being, including wellness and employee assistance programs.
In addition to base salary, medical benefits, and retirement benefits, including defined benefit pension plans covering substantially all employees and a 401(k) plan for eligible employees, our total rewards package includes short-term incentives and long-term stock-based compensation for certain employees. Further, we offer our employees various programs that encourage overall well-being, including wellness and employee assistance programs.
(b) Includes $119 million, $113 million, and $104 million in 2024, 2023, and 2022, respectively, of electric operating revenues from transmission services provided to Ameren Illinois Electric Distribution. 18 Table of Contents Electric Operating Statistics – Year Ended December 31, 2024 2023 2022 Ameren Missouri fuel costs (cents per kilowatthour generated) (a) 1.27 ¢ 1.29 ¢ 1.41 ¢ Source of Ameren Missouri energy supply: Coal 50.5 % 54.6 % 61.6 % Nuclear 29.1 25.6 21.6 Hydroelectric 3.5 2.4 3.2 Wind 4.4 4.9 4.7 Natural gas 1.0 1.1 1.1 Methane gas and solar 0.2 0.2 0.2 Purchased power – wind 0.4 0.6 0.8 Purchased power – other 10.9 10.6 6.8 Ameren Missouri total 100.0 % 100.0 % 100.0 % (a) Ameren Missouri fuel costs exclude $34 million, $72 million, and $(98) million in 2024, 2023, and 2022, respectively, for changes in FAC recoveries.
(b) Includes $160 million, $119 million, and $113 million in 2025, 2024, and 2023, respectively, of electric operating revenues from transmission services provided to Ameren Illinois Electric Distribution. 19 Table of Contents Electric Operating Statistics – Year Ended December 31, 2025 2024 2023 Ameren Missouri fuel costs (cents per kilowatthour generated) (a) 1.34 ¢ 1.27 ¢ 1.29 ¢ Source of Ameren Missouri energy supply: Coal 56.5 % 50.5 % 54.6 % Nuclear 19.4 29.1 25.6 Hydroelectric 3.5 3.5 2.4 Wind 3.6 4.4 4.9 Natural gas 1.8 1.0 1.1 Methane gas and solar 3.0 0.2 0.2 Purchased power – wind — 0.4 0.6 Purchased power – other 12.2 10.9 10.6 Ameren Missouri total 100.0 % 100.0 % 100.0 % (a) Ameren Missouri fuel costs exclude $(96) million, $34 million, and $72 million in 2025, 2024, and 2023, respectively, for changes in FAC recoveries.
The 2025 Change to the 2023 PRP is expected to include, among other things, the following: 10 Table of Contents • adding 1,600 MWs of natural gas-fired simple-cycle generation by 2030, which includes the 800-MW Castle Bluff Natural Gas Project 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 1,500 MWs of nuclear generation by 2040; • retiring all of Ameren Missouri’s coal-fired energy centers by 2042; • retiring 1,800 MWs of Ameren Missouri’s natural gas-fired energy centers by 2040 to comply with Illinois law; • the continued implementation of customer energy-efficiency and demand response programs; and • the expectation that Ameren Missouri will seek and receive NRC approval for an extension of the operating license for the Callaway Energy Center beyond its current 2044 expiration date.
The 2025 Change to the 2023 PRP includes, among other things, the following: 10 Table of Contents • 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 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; • retiring all of Ameren Missouri’s coal-fired energy centers by 2042; • retiring 1,800 MWs of Ameren Missouri’s natural gas-fired energy centers by 2040 to comply with Illinois law; • the continued implementation of customer energy-efficiency and demand response programs; and • the expectation that Ameren Missouri will seek and receive NRC approval for an extension of the operating license for the Callaway Energy Center beyond its current 2044 expiration date.
The FERC regulates Ameren Missouri’s, Ameren Illinois’, and ATXI’s cost-based rates for the wholesale transmission and distribution of energy in interstate commerce and various other matters discussed below under General Regulatory Matters. 8 Table of Contents The following table summarizes the key terms of the rate orders in effect for customer billings for each of Ameren’s utilities as of January 1, 2025, except as noted: Rate Regulator Effective Rate Order Issued In Rates Effective Allowed ROE Percent of Common Equity Rate Base (in billions) Portion of Ameren’s 2024 Operating Revenues (a) Ameren Missouri Electric service (b) MoPSC June 2023 July 2023 (c) (c) (c) 50% Natural gas delivery service MoPSC December 2021 February 2022 (d) (d) $0.3 2% Ameren Illinois Electric distribution delivery service (e) ICC December 2024 (e) 8.72% 50.00% (e) 27% Natural gas delivery service (f) ICC November 2023 November 2023 9.44% 50.00% $2.8 12% Electric transmission service (g) FERC (g) January 2025 10.48% 54.91% $4.4 6% ATXI Electric transmission service (g) FERC (g) January 2025 10.48% 60.08% $1.6 3% (a) Includes pass-through costs recovered from customers, such as purchased power for electric distribution delivery service and natural gas purchased for resale for natural gas delivery service, and intercompany eliminations.
The FERC regulates Ameren Missouri’s, Ameren Illinois’, and ATXI’s cost-based rates for the wholesale transmission and distribution of energy in interstate commerce and various other matters discussed below under General Regulatory Matters. 8 Table of Contents The following table summarizes the key terms of the rate orders in effect for customer billings for each of Ameren’s utilities as of January 1, 2026, except as noted: Rate Regulator Effective Rate Order Issued In Rates Effective Allowed ROE Percent of Common Equity Rate Base (in billions) Portion of Ameren’s 2025 Operating Revenues (a) Ameren Missouri Electric service (b) MoPSC April 2025 June 2025 (c) (c) (c) 52% Natural gas delivery service MoPSC July 2025 September 2025 (c) (c) (c) 2% Ameren Illinois Electric distribution delivery service (d) ICC December 2024 (d) 8.72% 50.00% (d) 26% Electric energy-efficiency investments (e) ICC November 2025 January 2026 10.65% 50.00% $0.5 1% Natural gas delivery service (f) ICC November 2025 December 2025 9.60% 50.00% $3.2 11% Electric transmission service (g) FERC (g) January 2026 10.48% 54.98% $4.6 6% ATXI Electric transmission service (g) FERC (g) January 2026 10.48% 60.02% $1.8 2% (a) Includes pass-through costs recovered from customers, such as purchased power for electric distribution delivery service and natural gas purchased for resale for natural gas delivery service, and intercompany eliminations.
(b) The Ameren Transmission segment also includes allocated Ameren (parent) interest charges, as well as other subsidiaries engaged in electric transmission project development and investment.
(b) Through 2025, the Ameren Transmission segment also included allocated Ameren (parent) interest charges, as well as other subsidiaries engaged in electric transmission project development and investment.
Natural Gas Operating Statistics – Year Ended December 31, 2024 2023 2022 Natural Gas Sales – dekatherms (in millions): Ameren Missouri: Residential 6 6 8 Commercial 3 3 4 Industrial 1 1 1 Transport 8 9 9 Ameren Missouri total 18 19 22 Ameren Illinois Natural Gas: Residential 47 47 59 Commercial 14 14 18 Industrial 3 3 6 Transport 99 99 99 Ameren Illinois Natural Gas total 163 163 182 Ameren total 181 182 204 Natural Gas Operating Revenues (in millions): Ameren Missouri: Residential $ 90 $ 100 $ 119 Commercial 37 46 56 Industrial 4 5 7 Transport and other 15 14 15 Ameren Missouri total $ 146 $ 165 $ 197 Ameren Illinois Natural Gas: Residential $ 661 $ 657 $ 846 Commercial 166 164 221 Industrial 10 14 41 Transport and other 101 62 72 Ameren Illinois Natural Gas total $ 938 $ 897 $ 1,180 Other and intercompany eliminations (1) (1) (1) Ameren total $ 1,083 $ 1,061 $ 1,376 Rate Base Statistics – At December 31, 2024 2023 2022 Rate Base (in billions): Electric transmission and distribution $ 18.5 $ 17.5 $ 15.4 Natural gas transmission and distribution 3.3 3.2 2.9 Coal generation: Labadie Energy Center 1.0 0.9 0.9 Sioux Energy Center 0.6 0.6 0.7 Rush Island Energy Center (retired in October 2024) — 0.4 0.4 Coal generation total 1.6 1.9 2.0 Nuclear generation 1.5 1.5 1.5 Renewable generation (hydroelectric, wind, solar, methane gas) 2.4 1.4 1.5 Natural gas generation 0.4 0.3 0.3 Rate base total $ 27.7 $ 25.8 $ 23.6 19 Table of Contents AVAILABLE INFORMATION The Ameren Companies make available free of charge through Ameren’s website (www.amereninvestors.com) their annual reports on Form 10-K, quarterly reports on Form 10-Q, current reports on Form 8-K, and any amendments to those reports filed with or furnished to the SEC pursuant to Sections 13(a) or 15(d) of the Exchange Act as soon as reasonably possible after such reports are electronically filed with, or furnished to, the SEC.
Natural Gas Operating Statistics – Year Ended December 31, 2025 2024 2023 Natural Gas Sales – dekatherms (in millions): Ameren Missouri: Residential 7 6 6 Commercial 4 3 3 Industrial 1 1 1 Transport 9 8 9 Ameren Missouri total 21 18 19 Ameren Illinois Natural Gas: Residential 52 47 47 Commercial 16 14 14 Industrial 3 3 3 Transport 100 99 99 Ameren Illinois Natural Gas total 171 163 163 Ameren total 192 181 182 Natural Gas Operating Revenues (in millions): Ameren Missouri: Residential $ 101 $ 90 $ 100 Commercial 44 37 46 Industrial 5 4 5 Transport and other 14 15 14 Ameren Missouri total $ 164 $ 146 $ 165 Ameren Illinois Natural Gas: Residential $ 680 $ 661 $ 657 Commercial 185 166 164 Industrial 12 10 14 Transport and other 91 101 62 Ameren Illinois Natural Gas total $ 968 $ 938 $ 897 Other and intercompany eliminations (1) (1) (1) Ameren total $ 1,131 $ 1,083 $ 1,061 Rate Base Statistics – At December 31, 2025 2024 2023 Rate Base (in billions): Electric transmission and distribution $ 20.3 $ 18.5 $ 17.5 Natural gas transmission and distribution 3.5 3.3 3.2 Coal generation: Labadie Energy Center 1.1 1.0 0.9 Sioux Energy Center 0.5 0.6 0.6 Rush Island Energy Center (retired in October 2024) — — 0.4 Coal generation total 1.6 1.6 1.9 Nuclear generation 1.6 1.5 1.5 Renewable generation (hydroelectric, wind, solar, methane gas) 2.4 2.4 1.4 Natural gas generation 0.4 0.4 0.3 Rate base total $ 29.8 $ 27.7 $ 25.8 20 Table of Contents AVAILABLE INFORMATION The Ameren Companies make available free of charge through Ameren’s website (www.amereninvestors.com) their annual reports on Form 10-K, quarterly reports on Form 10-Q, current reports on Form 8-K, and any amendments to those reports filed with or furnished to the SEC pursuant to Sections 13(a) or 15(d) of the Exchange Act as soon as reasonably possible after such reports are electronically filed with, or furnished to, the SEC.
The act also permits the MoPSC and the ICC to request that the FERC review cost allocations by Ameren Services to other Ameren subsidiaries. Operation of Ameren Missouri’s Callaway Energy Center is subject to regulation by the NRC. The license for the Callaway Energy Center expires in 2044.
The act also permits the MoPSC and the ICC to request that the FERC review cost allocations by Ameren Services to other Ameren subsidiaries. 9 Table of Contents Operation of Ameren Missouri’s Callaway Energy Center is subject to regulation by the NRC. The license for the Callaway Energy Center is currently set to expire in 2044.
As of December 31, 2024, these labor unions collectively represented 46%, 59%, 55%, and 10% of the employees at Ameren, Ameren Missouri, Ameren Illinois, and Ameren Services, respectively. The Ameren Companies expect continued constructive relationships with their respective labor unions.
As of December 31, 2025, these labor unions collectively represented 46%, 58%, 54%, and 10% of the employees at Ameren, Ameren Missouri, Ameren Illinois, and Ameren Services, respectively. The Ameren Companies expect continued constructive relationships with their respective labor unions.
While Ameren Missouri has minimum purchase obligations associated with these agreements, the majority of these agreements are not associated with any specific coal-fired energy center. Ameren Missouri burned approximately 10.7 million tons of coal in 2024.
While Ameren Missouri has minimum purchase obligations associated with these agreements, the majority of these agreements are not associated with any specific coal-fired energy center. Ameren Missouri burned approximately 12.0 million tons of coal in 2025.
HUMAN CAPITAL MANAGEMENT The execution of Ameren’s core strategy to invest in rate-regulated energy infrastructure, enhance regulatory frameworks and advocate for responsible policies, and optimize operating performance to capitalize on opportunities to benefit our customers, communities, shareholders, and the environment is driven by the capabilities and engagement of our workforce.
HUMAN CAPITAL MANAGEMENT The execution of Ameren’s core strategy to invest in rate-regulated energy infrastructure, enhance regulatory frameworks and advocate for responsible policies, and optimize operating performance is driven by the capabilities and engagement of our workforce.
The following table presents our employee count and their average tenure as of December 31, 2024, and the attrition rate in 2024: Employee Count Average Tenure (in years) Attrition Rate Ameren 8,981 13 7% Ameren Missouri 3,830 14 6% Ameren Illinois 3,108 13 6% Ameren Services 2,043 11 10% 15 Table of Contents The following table presents Ameren’s employees by generation as of December 31, 2024: Generation Description Ameren Ameren Missouri Ameren Illinois Ameren Services Baby Boomer (birth years between 1946 and 1964) 11% 11% 10% 11% Generation X (birth years between 1965 and 1980) 40% 40% 40% 42% Millennials (birth years between 1981 and 1996) 42% 41% 43% 40% Generation Z/Post Millennial (birth years after 1997) 7% 8% 7% 7% Collective bargaining units at Ameren’s subsidiaries consist of the International Brotherhood of Electrical Workers, the International Union of Operating Engineers, the Laborer’s International Union of North America, the United Association of Plumbers and Pipefitters, and the United Government Security Officers of America.
The following table presents our employee count and their average tenure as of December 31, 2025, and the attrition rate in 2025: Employee Count Average Tenure (in years) Attrition Rate Ameren 8,913 13 6% Ameren Missouri 3,767 14 6% Ameren Illinois 3,168 13 5% Ameren Services 1,978 11 9% The following table presents Ameren’s employees by generation as of December 31, 2025: Generation Description Ameren Ameren Missouri Ameren Illinois Ameren Services Baby Boomer (birth years between 1946 and 1964) 9% 9% 8% 10% Generation X (birth years between 1965 and 1980) 39% 39% 38% 41% Millennials (birth years between 1981 and 1996) 43% 43% 45% 41% Generation Z/Post Millennial (birth years after 1997) 9% 9% 9% 8% Collective bargaining units at Ameren’s subsidiaries consist of the International Brotherhood of Electrical Workers, the International Union of Operating Engineers, the Laborer’s International Union of North America, the United Association of Plumbers and Pipefitters, and 16 Table of Contents the United Government Security Officers of America.
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.
In 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. Ameren Missouri intends to invest $51 million in 2026 and $22 million in 2027 for customer energy-efficiency and demand response programs.
Ameren Missouri is also a member of the MRO, which is also one of the six regional entities and represents all or portions of 16 central, southern, and midwestern states, as well as two Canadian provinces, under authority from the NERC. The regional entities of the NERC work to safeguard the reliability of the bulk power systems throughout North America.
Ameren Missouri is also a member of the MRO, which is also one of the six regional entities and represents all or portions of 16 central, southern, and midwestern states, as well as two Canadian provinces, under authority from the NERC.
Environmental Matters Our electric generation, transmission, and distribution and natural gas distribution and storage operations must comply with a variety of statutes and regulations relating to the protection of the environment and human health and safety.
Environmental Matters Our electric generation, transmission, and distribution and natural gas distribution and storage operations must comply with a variety of statutes and regulations relating to the protection of the environment and human health and safety, including permitting programs implemented by federal, state, and local authorities.
For additional information, see Risk Factors under Part I, Item 1A, Outlook in Management’s Discussion and Analysis of Financial Condition and Results of Operations under Part II, Item 7, and Note 2 – Rate and Regulatory Matters, Note 9 – Callaway Energy Center, and Note 14 – Commitments and Contingencies under Part II, Item 8, of this report. 17 Table of Contents OPERATING STATISTICS The following tables present key electric and natural gas operating statistics for Ameren for the past three years: Electric Operating Statistics – Year Ended December 31, 2024 2023 2022 Electric Sales – kilowatthours (in millions): Ameren Missouri: Residential 13,041 12,839 13,915 Commercial 13,620 13,466 13,826 Industrial 4,096 3,977 4,090 Street lighting and public authority 65 71 76 Ameren Missouri retail load subtotal 30,822 30,353 31,907 Off-system sales 4,011 4,145 7,645 Ameren Missouri total 34,833 34,498 39,552 Ameren Illinois Electric Distribution (a) : Residential 10,945 10,774 11,708 Commercial 11,631 11,602 11,867 Industrial 10,949 10,740 10,981 Street lighting and public authority 386 385 410 Ameren Illinois Electric Distribution total 33,911 33,501 34,966 Eliminate affiliate sales — (30) (190) Ameren total 68,744 67,969 74,328 Electric Operating Revenues (in millions): Ameren Missouri: Residential $ 1,638 $ 1,577 $ 1,578 Commercial 1,313 1,280 1,219 Industrial 311 306 290 Other, including street lighting and public authority 100 124 171 Ameren Missouri retail load subtotal $ 3,362 $ 3,287 $ 3,258 Off-system sales and capacity 485 407 591 Ameren Missouri total $ 3,847 $ 3,694 $ 3,849 Ameren Illinois Electric Distribution: Residential $ 1,254 $ 1,344 $ 1,325 Commercial 680 747 768 Industrial 178 186 199 Other, including street lighting and public authority (23) (59) (36) Ameren Illinois Electric Distribution total $ 2,089 $ 2,218 $ 2,256 Ameren Transmission: Ameren Illinois Transmission (b) $ 564 $ 480 $ 424 ATXI 218 198 192 Eliminate affiliate revenues (1) (1) (1) Ameren Transmission total $ 781 $ 677 $ 615 Other and intersegment eliminations (177) (150) (139) Ameren total $ 6,540 $ 6,439 $ 6,581 (a) Sales for which power was supplied by Ameren Illinois as well as alternative retail electric suppliers.
For additional information, see Risk Factors under Part I, Item 1A, Outlook in Management’s Discussion and Analysis of Financial Condition and Results of Operations under Part II, Item 7, and Note 2 – Rate and Regulatory Matters, Note 9 – Callaway Energy Center, and Note 14 – Commitments and Contingencies under Part II, Item 8, of this report. 18 Table of Contents OPERATING STATISTICS The following tables present key electric and natural gas operating statistics for Ameren for the past three years: Electric Operating Statistics – Year Ended December 31, 2025 2024 2023 Electric Sales – kilowatthours (in millions): Ameren Missouri: Residential 13,675 13,041 12,839 Commercial 13,972 13,620 13,466 Industrial 4,087 4,096 3,977 Street lighting and public authority 62 65 71 Ameren Missouri retail load subtotal 31,796 30,822 30,353 Off-system sales 3,466 4,011 4,145 Ameren Missouri total 35,262 34,833 34,498 Ameren Illinois Electric Distribution (a) : Residential 11,516 10,945 10,774 Commercial 11,755 11,631 11,602 Industrial 10,485 10,949 10,740 Street lighting and public authority 398 386 385 Ameren Illinois Electric Distribution total 34,154 33,911 33,501 Eliminate affiliate sales — — (30) Ameren total 69,416 68,744 67,969 Electric Operating Revenues (in millions): Ameren Missouri: Residential $ 1,839 $ 1,638 $ 1,577 Commercial 1,450 1,313 1,280 Industrial 342 311 306 Other, including street lighting and public authority 88 100 124 Ameren Missouri retail load subtotal $ 3,719 $ 3,362 $ 3,287 Off-system sales and capacity 912 485 407 Ameren Missouri total $ 4,631 $ 3,847 $ 3,694 Ameren Illinois Electric Distribution: Residential $ 1,483 $ 1,254 $ 1,344 Commercial 785 680 747 Industrial 199 178 186 Other, including street lighting and public authority (68) (23) (59) Ameren Illinois Electric Distribution total $ 2,399 $ 2,089 $ 2,218 Ameren Transmission: Ameren Illinois Transmission (b) $ 637 $ 564 $ 480 ATXI 226 218 198 Eliminate affiliate revenues (1) (1) (1) Ameren Transmission total $ 862 $ 781 $ 677 Other and intersegment eliminations (224) (177) (150) Ameren total $ 7,668 $ 6,540 $ 6,439 (a) Sales for which power was supplied by Ameren Illinois as well as alternative retail electric suppliers.
As a part of our culture, every employee is expected to challenge any unsafe act, complete each workday safely, and provide feedback on safety and security matters.
We have enhanced our facilities and workforce policies and practices to increase collaboration and productivity. As a part of our culture, every employee is expected to challenge any unsafe act, complete each workday safely, and provide feedback on safety and security matters.
The SERC is one of six regional entities and represents all or portions of 16 central and southeastern states under authority from the NERC for the purpose of implementing and enforcing reliability standards approved by the FERC.
The SERC is one of six regional entities and represents all or portions of 16 central and southeastern states under authority from the NERC.
The Grid Plan outlines how Ameren Illinois expects to invest in electric distribution infrastructure in order to support grid modernization, clean energy, energy efficiency, and the state of Illinois’ renewable energy, equity, climate, electrification, and environmental 11 Table of Contents goals. Ameren Illinois’ next Grid Plan is required to be filed by mid-January 2026.
The Grid Plan outlines how Ameren Illinois expects to invest in electric distribution infrastructure in order to support grid modernization, clean energy, energy efficiency, and the state of Illinois’ renewable energy, equity, climate, electrification, and environmental goals. In January 2026, Ameren Illinois filed its Grid Plan for the years 2028 through 2031.
We recognize that the rewards package required to attract and retain talent over the long term is about more than pay and benefits; it is about the total employee experience and support of their overall well-being.
Complementing these efforts, our rewards program delivers a competitive and financially sustainable total rewards package that reinforces strong performance and supports engagement. We recognize that the rewards package required to attract and retain talent over the long term is about more than pay and benefits; it is about the total employee experience and support of their overall well-being.
NATURAL GAS SUPPLY FOR DISTRIBUTION Ameren Missouri and Ameren Illinois are responsible for the purchase and delivery of natural gas to their customers. Ameren Missouri and Ameren Illinois each develop and manage a portfolio of natural gas supply resources.
Ameren Illinois’ natural gas energy-efficiency program costs are recovered through a separate gas rider. 14 Table of Contents NATURAL GAS SUPPLY FOR DISTRIBUTION Ameren Missouri and Ameren Illinois are responsible for the purchase and delivery of natural gas to their customers. Ameren Missouri and Ameren Illinois each develop and manage a portfolio of natural gas supply resources.
Workforce The majority of our workforce is comprised of skilled-craft and STEM-related professional and technical employees. Our workforce has been stable, with a total attrition rate of 7% in 2024. The majority of employee attrition is attributable to employee retirements, generally allowing for thoughtful workforce and succession planning in advance of these planned transitions.
Our workforce has been stable, with a total attrition rate of 6% in 2025. The majority of employee attrition is a result of employee retirements, generally allowing for thoughtful workforce and succession planning in advance of these planned transitions.
If any of Ameren Missouri, Ameren Illinois, or ATXI is found not to be in compliance with these mandatory reliability standards, it could incur substantial monetary penalties and other sanctions.
The regional entities of the NERC implement and enforce reliability standards approved by the FERC to safeguard the reliability of the bulk power systems throughout North America. If any of Ameren Missouri, Ameren Illinois, or ATXI is found not to be in compliance with these mandatory reliability standards, it could incur substantial monetary penalties and other sanctions.
The electric energy-efficiency program investments and the return on those investments are collected from customers through a rider and are not included in the electric distribution service MYRP framework. Ameren Illinois’ natural gas energy-efficiency program costs are recovered through a rider.
The electric energy-efficiency program investments and the return on those investments are collected from customers through a rider and are not included in the electric distribution service MYRP or traditional regulatory rate review frameworks.
Based on amounts collected from customers and obligations under the program, the June 2018 through May 2019 reconciliation period is not expected to result in refunds to customers, pending review by the ICC.
Based on amounts collected from customers and obligations under the program, the June 2019 through May 2020 reconciliation period is not expected to result in refunds to customers, pending review by the ICC. The CRGA establishes an energy storage credit program, under which the IPA must hold statewide procurements for energy storage credits.
In doing so, we strive to align our employees to our mission and vision, improve safety, continuously improve operating performance, attract and retain top talent, and recognize employee contributions, among other things. We assess employee engagement through a variety of channels.
In doing so, we strive to align our employees to our mission and vision, improve safety, continuously improve operating performance, attract and retain top talent, and recognize employee contributions, among other things. We seek employee feedback through confidential surveys and other channels, using insights to enhance the employee experience and take actions aimed at increasing employee engagement.
In addition to comprehensive safety and security standards, and mandatory health, safety, and security training programs for applicable employees, we promote programs designed to encourage employees to provide feedback on practices or actions that could harm employees, customers, or the Ameren Companies, including perceived issues related to safety, security (both physical and cyber), ethics and compliance violations, or acts of discrimination.
In addition to comprehensive safety and security standards, and mandatory health, safety, and security training programs for applicable employees, we promote programs designed to encourage employees to provide feedback on practices or actions that could harm employees, customers, or the Ameren Companies, including perceived issues related to safety, security (both physical and cyber), ethics and compliance violations, or policy concerns. 15 Table of Contents Leadership Development Ameren’s leaders play a critical role in setting and executing Ameren’s strategic initiatives, modeling our values and culture, and engaging and enabling the workforce.
Ameren Illinois’ planned investments in electric energy-efficiency programs is approximately $120 million in 2025 and approximately $125 million annually from 2026 to 2029. Every four years, Ameren Illinois is required to file a four-year electric energy-efficiency plan with the ICC.
Every four years, Ameren Illinois is required to file a four-year electric energy-efficiency plan with the ICC. 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.
For discussion of environmental matters, including NO x and SO 2 emission reduction requirements, regulation of CO 2 emissions, wastewater discharge standards, remediation efforts, and CCR management regulations, and a discussion of litigation against Ameren Missouri with respect to NSR, the Clean Air Act, and Missouri law in connection with projects at Ameren Missouri’s Rush Island Energy Center, see Note 14 – Commitments and Contingencies under Part II, Item 8, of this report.
For discussion of environmental matters, including NO x and SO 2 emission reduction requirements, regulation of CO 2 emissions, wastewater discharge standards, remediation efforts, and CCR management regulations, see Note 14 – Commitments and Contingencies under Part II, Item 8, of this report.
The 10.48% return, which includes a 50-basis-point incentive adder for participation in an RTO, is based on the FERC’s October 2024 order.
They are determined by a company-specific, forward-looking formula ratemaking framework based on each year’s forecasted information. The 10.48% return, which includes a 50-basis-point incentive adder for participation in an RTO, is based on the FERC’s October 2024 order.
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.
Pursuant to the CRGA, beginning in 2027, the ROE for electric energy-efficiency investments will be based on the most recently approved Ameren Illinois electric distribution ROE. 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.
Leadership Ameren’s leaders play a critical role in setting and executing Ameren’s strategic initiatives, modeling our values and culture, and engaging and enabling the workforce. As such, we seek to develop a strong leadership team with a variety of experiences and perspectives. Management engages in an extensive succession planning process annually, which includes the involvement of Ameren’s board of directors.
As such, we seek to develop a strong leadership team with a variety of experiences and perspectives. Management engages in an extensive succession planning process annually, which includes the involvement of Ameren’s board of directors. We develop our leaders both individually, through job rotations, coaching, work experiences, and leadership development programs, and as a team.
Delays and disruptions in coal deliveries could cause Ameren Missouri to pursue a strategy that could include reducing off-system sales of power during low-earning periods, buying higher-cost fuels to generate required electricity, and purchasing power from other sources.
Delays and disruptions in coal deliveries could cause Ameren Missouri to pursue a strategy that could include reducing off-system sales of power during low-earning periods, buying higher-cost fuels to generate required electricity, and purchasing power from other sources. 12 Table of Contents Nuclear The production of nuclear fuel involves the mining and milling of uranium ore to produce uranium concentrates, the conversion of uranium concentrates to uranium hexafluoride gas, the enrichment of that gas, the conversion of the enriched uranium hexafluoride gas into uranium dioxide fuel pellets, and the fabrication into fuel assemblies.
Illinois law also required Ameren Illinois to enter into contracts to purchase zero emission credits in an amount equal to approximately 16% of the actual amount of electricity delivered to retail customers during calendar year 2014, pursuant to Illinois’ zero emission standard.
For additional information regarding the CRGA, see Note 2 – Rate and Regulatory Matters under Part II, Item 8, of this report. 13 Table of Contents Illinois law also required Ameren Illinois to enter into contracts to purchase zero emission credits in an amount equal to approximately 16% of the actual amount of electricity delivered to retail customers during calendar year 2014, pursuant to Illinois’ zero emission standard.
Foundational to our workforce strategy are our core competencies of: • Be Strategic • Continuously Improve • Deliver Results • Engage Respectfully • Foster Collaboration • Think Customer Ameren’s chief executive officer and chief human resources officer, with the support of other leaders of the Ameren Companies, are responsible for developing and executing our workforce strategy.
Ameren’s Chief Executive Officer and our Chief Human Resources Officer, with the support of other leaders of the Ameren Companies, are responsible for developing and executing our workforce strategy.
Ameren Illinois In Illinois, while electric transmission and distribution service rates are regulated, power supply prices are not. Although electric customers are allowed to purchase power from an alternative retail electric supplier, Ameren Illinois is required to be the provider of last resort for its electric distribution customers.
Although electric customers are allowed to purchase power from an alternative retail electric supplier, Ameren Illinois is required to be the provider of last resort for its electric distribution customers. In 2025, 2024, and 2023, Ameren Illinois procured power on behalf of its customers for 28%, 25%, and 28%, respectively, of its total kilowatthour sales.
The IPA establishes its long-term renewable resources procurement plans in a filing made every two years. In February 2024, the ICC approved the IPA’s latest long-term renewable resources procurement plan, which established the 2024 and 2025 renewable energy credit procurement targets.
In February 2026, the ICC approved the IPA’s latest long-term renewable resources procurement plan, which established the 2026 and 2027 renewable energy credit procurement targets.
The order approved an average annual rate base for 2024, 2025, 2026, and 2027 of $4.2 billion, $4.4 billion, $4.6 billion, and $4.8 billion, respectively. Rate changes consistent with the December 2024 order became effective in late December 2024.
(c) This rate order did not specify an ROE, capital structure, or rate base. (d) In December 2024, the ICC approved an average annual rate base for 2024, 2025, 2026, and 2027 of $4.2 billion, $4.4 billion, $4.6 billion, and $4.8 billion, respectively.
The addition of renewable, natural gas-fired, or nuclear generation facilities is subject to obtaining necessary project approvals, including FERC approval and the issuance of a CCN by the MoPSC, as applicable.
The addition of renewable, natural gas-fired, or nuclear generation facilities is subject to obtaining necessary project approvals, including FERC approval and the issuance of a CCN by the MoPSC, as applicable. Additionally, in February 2026, Ameren Missouri executed electric service agreements with large load customers under the large load customer rate plan, representing 2.2 gigawatts of demand.
Missouri law required Ameren Missouri to offer solar rebates through December 2023 and currently requires Ameren Missouri to offer net metering to certain customers that install renewable generation at their premises.
Illinois law currently requires Ameren Illinois to offer rebates and net metering to certain customers who install renewable generation.
Pursuant to the CEJA, if funds collected from customers are not used to procure renewable energy credits, they would be refunded to customers pursuant to an annual reconciliation proceeding, the first of which was approved by the ICC in January 2025, which was the June 2017 through May 2018 reconciliation period, and did not result in refunds to customers.
Pursuant to the CEJA, if funds collected from customers are not used to procure renewable energy credits, they would be refunded to customers pursuant to an annual reconciliation proceeding.
SUPPLY OF ELECTRIC POWER Capacity Ameren Missouri sells all of its capacity to the MISO and purchases the capacity it needs to supply its native load sales from the MISO. Ameren Illinois purchases capacity from the MISO and through bilateral contracts resulting from IPA procurement events.
The ICC and IPA must publish the study by December 2026. SUPPLY OF ELECTRIC POWER Capacity Ameren Missouri offers for sale all of its capacity to the MISO and purchases the capacity it needs to supply its native load sales from the MISO.
The information on Ameren’s website, or any other website referenced in this report, is not incorporated by reference into this report.
In addition, we provide information regarding our sustainability initiatives through our website, including our annual sustainability and impact report and a sustainability investor presentation. The information or other documents on Ameren’s website, or any other website referenced in this report, is not incorporated by reference into this report.
Our workforce strategy is anchored in four key pillars: Culture, Leadership, Talent, and Rewards, which are discussed further below.
Our workforce strategy is anchored in four key pillars: Culture; Leadership Development; Organizational Alignment and Work Optimization; and Talent Attraction, Development and Rewards, which are discussed further below. We are committed to workforce practices that adhere to laws and regulations regarding non-discrimination.
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.
In addition, the order approved an immaterial amount of performance incentives applicable to each plan year to earn revenues by achieving certain spending and demand response goals.
The Huck Finn, Boomtown, and Cass County energy centers are solar generation facilities. The Osage and Keokuk energy centers generate electricity using hydroelectric dams located on the Lake of the Ozarks and the Mississippi River, respectively. The Maryland Heights Energy Center generates electricity by burning methane gas collected from a landfill.
The Osage and Keokuk energy centers generate electricity using hydroelectric dams located on the Lake of the Ozarks and the Mississippi River, respectively.
We develop our leaders both individually, through job rotations, mentoring and sponsorships, work experiences, and leadership development programs, and as a team. Throughout the year, we offer a variety of forums intended to connect our leaders to our mission, values, strategy and culture, and build leadership skills and capabilities.
Throughout the year, we offer a variety of forums intended to connect our leaders to our mission, vision, values, strategy, and culture, and to build leadership skills and capabilities. Organizational Alignment and Work Optimization We regularly evaluate our organizational structure and make adjustments and expand roles to facilitate execution of our strategy and organizational efficiency.
INDUSTRY ISSUES We are facing issues common to the electric and natural gas utility industry, as well as new and emergent issues impacting the industry as a whole.
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. INDUSTRY ISSUES We are facing issues common to the electric and natural gas utility industry, as well as new and emergent issues impacting the industry as a whole.
RENEWABLE ENERGY AND ZERO EMISSION STANDARDS Missouri and Illinois laws require electric utilities to include renewable energy resources in their portfolios.
For additional information regarding newly constructed or acquired energy centers, see Note 2 – Rate and Regulatory Matters under Part II, Item 8, of this report. RENEWABLE ENERGY AND ZERO EMISSION STANDARDS Missouri and Illinois laws require electric utilities to include renewable energy resources in their portfolios.
Ameren Missouri continues to evaluate its longer-term needs for new generating capacity.
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. Ameren Missouri continues to evaluate its longer-term needs for new generating capacity.
Ameren Illinois is required to file an updated four-year electric energy-efficiency plan with the ICC by March 2025. Illinois law allows Ameren Illinois to earn a return on its electric energy-efficiency program investments.
Pursuant to the CRGA, Ameren Illinois is required to file an updated electric energy-efficiency plan for 2027 through 2029 by June 1, 2026 to reflect a higher annual cap on spending.
Beginning with the April 2023 auction for the June 2023 to May 2024 planning year, auctions include four seasonal load forecasts and available capacity levels and are designed to cover each season’s peak demand plus a target reserve margin.
Ameren Illinois purchases all of its capacity from the MISO and hedges those purchases through bilateral contracts resulting from IPA procurement events. MISO auctions establish capacity for four seasonal peak load forecasts and are designed to cover each season’s peak demand plus a target reserve margin. Ameren Missouri Ameren Missouri’s electric supply is primarily generated from its energy centers.
Removed
(c) This rate order did not specify an ROE, capital structure, or rate base. (d) This rate order did not specify an ROE or a capital structure. (e) In December 2024, the ICC issued an order in Ameren Illinois’ MYRP proceeding.
Added
In December 2025, the ICC approved a year end rate base for 2024 of $4.2 billion. Rate changes consistent with the December 2025 reconciliation order became effective in January 2026. (e) Ameren Illinois electric energy-efficiency investment rates are updated annually and become effective each January.

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Item 1A. Risk Factors

Risk Factors — what could go wrong, per management

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Biggest changeThese factors include, but are not limited to, the following: project management expertise; 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; escalating costs, including but not limited to changes to tariffs on materials or government actions; changes in the scope and timing of projects; the ability to obtain required regulatory, project, and permit approvals; the ability to obtain necessary rights-of-way, easements, and transmission connection agreements at an acceptable cost in a timely fashion; 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. 24 Table of Contents 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; 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; new and/or changes in environmental regulations, including those related to CO 2 and other greenhouse gas emissions; energy prices; and demand.
Biggest changeWith 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 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; and demand.
Additionally, the use and handling of various chemicals or 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.
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.
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.
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 possible closure of the Venice Energy Center by the end of 2029.
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.
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.
Such declines could occur due to a number of factors, including: • customer energy-efficiency programs that are designed to reduce energy demand; • energy-efficiency efforts by customers not related to our energy-efficiency programs; • 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; and • macroeconomic factors resulting in low economic growth or contraction within our service territories, which could reduce energy demand.
Such declines could occur due to a number of factors, including: • customer energy-efficiency programs that are designed to reduce energy demand; • 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; and • macroeconomic factors resulting in low economic growth or contraction within our service territories, which could reduce energy demand.
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. As owners and operators of bulk power transmission systems and electric energy centers, we are subject to mandatory NERC reliability standards, including cybersecurity standards.
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 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.
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.
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.
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.
Ameren Missouri’s ownership of the Callaway Energy Center subjects it to risks associated with nuclear generation, including: • potential harmful effects on the environment and human health resulting from radiological releases associated with the operation of nuclear facilities and the storage, handling, and disposal of radioactive materials; • continued uncertainty regarding the federal government’s plan to permanently store spent nuclear fuel and, as a result, the need to provide for long-term storage of spent nuclear fuel at the Callaway Energy Center; • limitations on the amounts and types of insurance available to cover losses that might arise in connection with the Callaway Energy Center or other United States nuclear facilities; • uncertainties about contingencies and retrospective insurance premium assessments relating to claims at the Callaway Energy Center or other United States nuclear facilities; • public and governmental concerns about the safety and adequacy of security at nuclear facilities; • limited availability of fuel supply and our reliance on licensed fuel assemblies from primarily one NRC-licensed supplier of Callaway Energy Center’s assemblies; • costly and extended outages for scheduled or unscheduled maintenance and refueling; • uncertainties about the technological and financial aspects of decommissioning nuclear facilities at the end of their licensed lives; • the ability to continue to attract and retain qualified labor to operate the Callaway Energy Center; • the adverse effect of poor market performance and other economic factors on the asset values of nuclear decommissioning trust funds and the corresponding increase, upon MoPSC approval, in customer rates to fund the estimated decommissioning costs; and • potential adverse effects of a natural disaster, acts of sabotage or terrorism, including a cyber attack, or any accident leading to a radiological release.
Ameren Missouri’s ownership of the Callaway Energy Center subjects it to risks associated with nuclear generation, including: • potential harmful effects on the environment and human health resulting from radiological releases associated with the operation of nuclear facilities and the storage, handling, and disposal of radioactive materials; • continued uncertainty regarding the federal government’s plan to permanently store spent nuclear fuel and, as a result, the need to provide for long-term storage of spent nuclear fuel at the Callaway Energy Center; • limitations on the amounts and types of insurance available to cover losses that might arise in connection with the Callaway Energy Center or other United States nuclear facilities; 26 Table of Contents • uncertainties about contingencies and retrospective insurance premium assessments relating to claims at the Callaway Energy Center or other United States nuclear facilities; • public and governmental concerns about the safety and adequacy of security at nuclear facilities; • limited availability of fuel supply and our reliance on licensed fuel assemblies from primarily one NRC-licensed supplier of Callaway Energy Center’s assemblies; • 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; • the ability to continue to attract and retain qualified labor to operate the Callaway Energy Center; • the adverse effect of poor market performance and other economic factors on the asset values of nuclear decommissioning trust funds and the corresponding increase, upon MoPSC approval, in customer rates to fund the estimated decommissioning costs; and • potential adverse effects of a natural disaster, acts of sabotage or terrorism, including a cyber attack, or any accident leading to a radiological release.
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. 23 Table of Contents Ameren is targeting 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.
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. Ameren is targeting 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.
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.
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 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.
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.
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.
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 28 Table of Contents increased use of distributed generation by our customers.
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.
Certain specialized knowledge that focuses on skilled-craft and STEM-related disciplines is required to construct and operate generation, transmission, and distribution assets. Further, a significant portion of our work force is nearing retirement. As of December 31, 2024, approximately 23% of Ameren’s, Ameren Missouri’s, and Ameren Illinois’ total employees were 55 years old or older.
Certain specialized knowledge that focuses on skilled-craft and STEM-related disciplines is required to construct and operate generation, transmission, and distribution assets. Further, a significant portion of our work force is nearing retirement. As of December 31, 2025, approximately 22% of Ameren’s, Ameren Missouri’s, and Ameren Illinois’ total employees were 55 years old or older.
Any of these consequences could adversely affect our results of operations, financial position, and liquidity. We are subject to employee workforce factors that could adversely affect our operations. Our businesses depend upon our ability to employ and retain key officers and other skilled professional and technical employees.
Any of these consequences could adversely affect our results of operations, financial position, and liquidity. 29 Table of Contents We are subject to employee workforce factors that could adversely affect our operations. Our businesses depend upon our ability to employ and retain key officers and other skilled professional and technical employees.
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.
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.
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.
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.
Rate orders are also subject to appeal, which creates additional uncertainty as to the rates that we will ultimately be allowed to 21 Table of Contents 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.
Such environmental laws regulate air emissions; protect water bodies; manage the handling and disposal of hazardous substances and waste materials; siting and land use requirements; and potential ecological impacts. Complex and lengthy processes are required to obtain and renew approvals, permits, and licenses for new, existing, or modified energy-related facilities.
Such environmental laws regulate air emissions; protect water bodies; regulate the handling and disposal of hazardous substances and waste materials; establish siting and land use requirements; and protect against ecological impacts. Complex and lengthy processes are required to obtain and renew approvals, permits, and licenses for new, existing, or modified energy-related facilities.
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; 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; and constructively engaging with legislators, regulators, investors, customers, and other stakeholders to support outcomes leading to a net-zero future.
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 storage; and constructively engaging with legislators, regulators, investors, customers, and other stakeholders to support outcomes leading to a net-zero future.
Assumptions related to future costs, returns on investments, interest rates, timing of employee retirements, and mortality, as well as other actuarial matters, have a significant impact on our customers’ rates and our plan funding requirements. Ameren’s total pension and postretirement benefit plans were overfunded by $734 million as of December 31, 2024.
Assumptions related to future costs, returns on investments, interest rates, timing of employee retirements, and mortality, as well as other actuarial matters, have a significant impact on our customers’ rates and our plan funding requirements. Ameren’s total pension and postretirement benefit plans were overfunded by $954 million as of December 31, 2025.
Ameren Missouri’s ability to obtain an adequate supply of coal could limit operation of its coal-fired energy centers. 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.
Ameren Missouri’s ability to obtain an adequate supply of coal could limit operation of its coal-fired energy centers. Ameren Missouri owns and operates coal-fired energy centers. Approximately 96% of Ameren Missouri’s coal is purchased from the Powder River Basin in Wyoming, which has a limited number of suppliers.
Ameren Missouri and Ameren Illinois estimate that their portion of the future funding requirements will be 40% and 50%, respectively. These estimated contributions may change based on actual investment performance, changes in interest rates, changes in our assumptions, changes in government regulations, and any voluntary contributions.
Ameren Missouri and Ameren Illinois estimate that their portion of the future funding requirements will be 35% and 45%, respectively. These estimated contributions may change based on actual investment performance, changes in interest rates, changes in our assumptions, changes in government regulations, and any voluntary contributions.
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.
Any of the foregoing could have an adverse effect on our results of operations, financial positions, and liquidity. 23 Table of Contents We are subject to business and financial risks related to the impact of climate-related legislation, regulation, and emission reduction initiatives.
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.
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.
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.
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 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.
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.
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.
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.
The age of these energy centers increases the risks of unplanned outages, reduced generation output, and higher 26 Table of Contents maintenance expense.
The age of these energy centers increases the risks of unplanned outages, reduced generation output, and higher maintenance expense.
These factors include depressed economic conditions, a recession, 29 Table of Contents 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 30 Table of Contents instability, war, terrorism, and extreme volatility in the debt, equity, or credit markets.
We are also party to collective bargaining agreements that collectively represent about 46%, 59%, and 55% of Ameren’s, Ameren Missouri’s and Ameren Illinois’ total employees, respectively. The Ameren Missouri collective bargaining unit contracts expire in 2025 and 2026, and cover 4% and 96% of represented employees, respectively.
We are also party to collective bargaining agreements that collectively represent about 46%, 58%, and 54% of Ameren’s, Ameren Missouri’s and Ameren Illinois’ total employees, respectively. The Ameren Missouri collective bargaining unit contracts expire in 2026 and 2028, and cover 96% and 4% of represented employees, respectively.
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.
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.
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.
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, 2025, coal inventory was near targeted levels at the Labadie Energy Center and at targeted levels at the Sioux Energy Center.
Operation of these facilities involves many risks, including: • facility shutdowns due to operator error, or a failure of equipment or processes; • longer-than-anticipated maintenance outages; • failures of equipment that can result in unanticipated liabilities or unplanned outages; • aging infrastructure that may require significant expenditures to operate and maintain; • natural gas leaks or explosions near populated areas, including residential areas, business centers, industrial sites, and other public gathering places; • lack of adequate water required for cooling plant operations and to operate hydroelectric energy centers; • labor disputes; • disruptions in the delivery of electricity and natural gas to our customers; • 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; • 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; • suppliers and contractors who do not perform as required under their contracts, including those obligations that are affected by supply chain disruptions; • failure of other operators’ facilities and the effect of that failure on our electric and natural gas systems and customers; • inability to comply with regulatory requirements or obtain permits, including those relating to environmental laws; • 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; • 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; • accidents that might result in injury or loss of life, extensive property damage, or environmental damage; • ineffective vegetation management programs; • cybersecurity risks, including loss of operational control of Ameren Missouri’s energy centers and our transmission and distribution systems and loss of data, including sensitive customer, employee, financial, and operating system information, through insider or outsider actions; • limitations on amounts of insurance available to cover losses that might arise in connection with operating our electric generation facilities, electric and natural gas transmission and distribution facilities, and natural gas storage facilities; • inability to implement or maintain information systems; • failure to keep pace with and the ability to adapt to rapid technological change; and • other unanticipated operations and maintenance expenses and liabilities. 25 Table of Contents The foregoing risks could affect the operations of our facilities, impede our ability to meet regulatory requirements, or expose us to an increase in litigation, which could increase operating costs, increase our capital requirements and costs, reduce our revenues, or have an adverse effect on our liquidity.
Operation of these facilities involves many risks, including: • facility shutdowns due to operator error, or a failure of equipment or processes; • longer-than-anticipated maintenance outages; • failures of equipment that can result in unanticipated liabilities or unplanned outages; • aging infrastructure that may require significant expenditures to operate and maintain; • natural gas leaks or explosions near populated areas, including residential areas, business centers, industrial sites, and other public gathering places; • lack of adequate water required for cooling plant operations and to operate hydroelectric energy centers; 25 Table of Contents • labor disputes; • disruptions in the delivery of electricity and natural gas to our customers; • 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; • 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, among other things; • suppliers and contractors who do not perform as required under their contracts, including those obligations that are affected by supply chain disruptions; • failure of other operators’ facilities and the effect of that failure on our electric and natural gas systems and customers; • inability to comply with regulatory requirements or obtain permits, including those relating to environmental laws; • 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-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; • 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; • ineffective vegetation management programs; • cybersecurity risks, including loss of operational control of Ameren Missouri’s energy centers and our transmission and distribution systems and loss of data, including sensitive customer, employee, financial, and operating system information, through insider or outsider actions; • limitations on amounts of insurance available to cover losses that might arise in connection with operating our electric generation facilities, electric and natural gas transmission and distribution facilities, and natural gas storage facilities; • inability to implement or maintain information systems; • failure to keep pace with and the ability to adapt to rapid technological change, including generative and agentic artificial intelligence; and • other unanticipated operations and maintenance expenses and liabilities.
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.
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.
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; 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.
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 and energy prices; operational performance of low- to zero-carbon resources; new transmission infrastructure; 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.
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.
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.
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.
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.
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 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.
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 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.
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. As of December 31, 2024, Ameren Missouri’s coal-fired energy centers represented 6% and 11% of Ameren’s and Ameren Missouri’s rate base, respectively.
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.
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 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.
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.
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.
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.
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.
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.
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 have considered initiatives to further restrict greenhouse gases to address global climate-related risks.
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.
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.
These mechanisms could be changed or terminated. 20 Table of Contents Ameren Missouri’s electric and natural gas utility rates and Ameren Illinois’ natural gas utility rates are typically established in regulatory proceedings that take up to 11 months to complete.
These mechanisms could be changed or terminated. Ameren Missouri’s electric and natural gas utility rates and Ameren Illinois’ natural gas utility rates are typically established in regulatory proceedings that take up to 11 months to complete. Ameren Missouri’s electric and natural gas utility rates established in those proceedings are based on historical costs, revenues, and sales volumes.
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.
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 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.
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.
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.
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.
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.
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.
The FERC also conducts audits and reviews of Ameren Missouri’s, Ameren Illinois’, and ATXI’s accounting records to assess the accuracy of their respective formula ratemaking process, and it can require refunds to be issued to customers for previously billed amounts, with interest.
The FERC also conducts audits and reviews of Ameren Missouri’s, Ameren Illinois’, and ATXI’s accounting records to assess the accuracy of their respective formula ratemaking process, and it can require refunds to be issued to customers for previously billed amounts, with interest. 24 Table of Contents Additionally, pursuant to the CEJA, Illinois utilities are subject to requirements and provisions related to ethical conduct, including submitting an annual ethics and compliance report to the ICC.
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. 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.
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.
Ameren Missouri’s electric and natural gas utility rates established in those proceedings are based on historical costs, revenues, and sales volumes. Ameren Illinois’ natural gas rates established in those proceedings are based on estimated future 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.
Higher than expected inflation levels could continue to put pressure on the prices of labor, services, materials and supplies, and other costs.
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.
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.
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.
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.
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.
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 .
We estimate that we will invest up to $27.4 billion (Ameren Missouri – up to $17.5 billion; Ameren Illinois – up to $7.0 billion; ATXI – up to $2.9 billion) of capital expenditures from 2025 through 2029.
We estimate that we will invest up to $33.1 billion (Ameren Missouri – up to $22.2 billion; Ameren Illinois – up to $8.3 billion; ATXI – up to $2.6 billion) of capital expenditures from 2026 through 2030.
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.
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.
Certain financing agreements, corporate organizational documents, and certain statutory and regulatory requirements may impose restrictions on the ability of Ameren Missouri, Ameren Illinois, and ATXI to transfer funds to Ameren in the form of cash dividends, loans, or advances.
Certain financing agreements, corporate organizational documents, and certain statutory and regulatory requirements may impose restrictions on the ability of Ameren Missouri, Ameren Illinois, and ATXI to transfer funds to Ameren in the form of cash dividends, loans, or advances. 28 Table of Contents 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.
Forecasted energy demand from potential new customers and electrification might not be realized. 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.
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.
Increased capital expenditures could cause incremental PISA deferrals to exceed the 2.5% limitation, and such amounts exceeding the 2.5% limitation would be excluded from recovery under future revenue requirements. Failure to limit capital investments to an amount which maintains PISA deferrals under the 2.5% limitation could adversely affect Ameren’s and Ameren Missouri’s results of operations, financial position, and liquidity.
Failure to limit capital investments to an amount which maintains PISA deferrals under the 2.25% limitation could adversely affect Ameren’s and Ameren Missouri’s results of operations, financial position, and liquidity. 22 Table of Contents We are subject to various environmental and permitting laws. Significant capital expenditures may be required to achieve and to maintain compliance with these environmental laws.
The Ameren Illinois collective bargaining unit contracts expire in 2026 and 2027, and cover 92% and 8% of represented employees, respectively.
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.
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 United States withdrew from the Paris Agreement and the United Nations Framework Convention on Climate Change in January 2025 and 2026, respectively.
Removed
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.
Added
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.
Removed
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.
Added
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.
Removed
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.
Added
These factors include, but are not limited to, the following: project management expertise; 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; escalating costs, including but not limited to changes to tariffs on materials or government actions; changes in the scope and timing of projects; the ability to obtain required regulatory, project, and permit approvals; the ability to obtain necessary rights-of-way, easements, and transmission connection agreements at an acceptable cost in a timely fashion; unsatisfactory performance by the projects when completed; 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.
Removed
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.
Added
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.
Removed
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.
Added
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.
Removed
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.
Added
The foregoing risks could affect the operations of our facilities, impede our ability to meet regulatory requirements, or expose us to an increase in litigation, which could increase operating costs, increase our capital requirements and costs, reduce our revenues, or have an adverse effect on our liquidity.
Removed
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.
Added
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.
Removed
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.

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Item 1C. Cybersecurity

Cybersecurity — threats and controls disclosure

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Biggest changeAmeren's cybersecurity program and team are led by the Chief Information Security Officer, who possesses over 25 years of critical infrastructure experience both managing and protecting information systems in concert with extensive cybersecurity operations and leadership roles.
Biggest changeAmeren's cybersecurity program and team are led by the Chief Information Security Officer, who has nearly two decades of experience in cybersecurity, information technology, risk management, and business operations across the power and utilities sector and other industries.
To manage against existing and emerging cybersecurity threats, we maintain enterprise-wide cybersecurity, crisis management, and information security policies and regular training and tests that reinforce the acceptable use of Ameren's information assets, protection of customer and employee data, and the role each employee plays in protecting Ameren against cybersecurity threats.
To manage against existing and emerging cybersecurity threats, we maintain enterprise-wide cybersecurity, crisis management, and information security policies and regular awareness training and tests that reinforce the acceptable use of Ameren's information assets, protection of customer and employee data, and the role each employee plays in protecting Ameren against cybersecurity threats.
The committee receives regular updates from the Chief Information Security Officer, the Chief Information Officer, executive management, and other members of senior management who collectively maintain the responsibility for both the execution and ongoing management of Ameren’s cybersecurity program and respective initiatives.
The committee receives regular updates from the Chief Information Security Officer, the Chief Digital and Information Officer, executive management, and other members of senior management who collectively maintain the responsibility for both the execution and ongoing management of Ameren’s cybersecurity program and respective initiatives.
The committee has primary responsibility for oversight of cybersecurity and digital technology risk management, including the programs, policies, procedures, processes, controls and safeguards for digital technology, information security, prevention and detection of cybersecurity incidents or data breaches, and cybersecurity and digital technology matters as they relate to crisis preparedness, incident response plans, and disaster recovery and business continuity capabilities.
The committee has primary responsibility for oversight of cybersecurity and digital technology risk management, including the programs, policies, procedures, processes, controls and safeguards for digital technology, information security, prevention and detection of cybersecurity incidents or data breaches, legislative and regulatory compliance, and cybersecurity and digital technology matters as they relate to crisis preparedness, incident response plans, and disaster recovery and business continuity capabilities.
Our program effectiveness is measured through formal cybersecurity scorecards and metrics reported to senior-level Ameren officers, the risk management steering 30 Table of Contents committee, and the Cybersecurity and Digital Technology Committee.
Our program effectiveness is 31 Table of Contents measured through formal cybersecurity scorecards and metrics reported to senior-level Ameren officers, the risk management steering committee, and the Cybersecurity and Digital Technology Committee.
Ameren employs a third-party cybersecurity risk management program, which extends the governance elements of Ameren’s cybersecurity program, in addition to other diligence measures, to our critical third-party providers and suppliers.
Ameren applies a third-party cybersecurity risk management program, which extends the governance elements of Ameren’s cybersecurity program, in addition to other diligence measures, to our critical third-party providers and suppliers.
The Chief Information Security Officer regularly engages with senior-level Ameren officers, reports to the risk management steering committee, and has recurring meetings with the Cybersecurity and Digital Technology Committee as part of ongoing risk management and oversight of the cybersecurity program. In addition, Ameren’s board of directors participate in periodic cybersecurity drills to prepare for potential crisis scenarios.
The Chief Information Security Officer regularly engages with senior-level Ameren officers, reports to the risk management steering committee, and has recurring meetings with the Cybersecurity and Digital Technology Committee as part of ongoing risk management and oversight of the cybersecurity program. In addition, Ameren’s board of directors participates in threat briefings and periodic drills to prepare for potential crisis scenarios.
The supply chain and third-party risks introduced to Ameren are evaluated prior to the commencement of any new engagement or relationship, monitored closely throughout the lifecycle of the supplier and managed through privacy and cybersecurity provisions within the respective commercial contracts. Procedures have been established to address supplier incidents as well as supplier off-boarding at the expiration of the relationship.
The supply chain and third-party risks introduced to Ameren are evaluated prior to the commencement of any new engagement or relationship, monitored closely throughout the lifecycle of the supplier relationship and managed through data privacy and cybersecurity provisions within the respective commercial contracts.
We leverage common and widely accepted external cybersecurity risk management frameworks, such as the National Institute of Standards and Technology Cybersecurity framework, to assess, guide, and enhance our cybersecurity posture.
Procedures have been established to address supplier incidents as well as supplier off-boarding at the expiration of the relationship. We leverage common and widely accepted external cybersecurity risk management frameworks, such as the National Institute of Standards and Technology Cybersecurity framework, to assess, guide, and enhance our cybersecurity posture.
Added
The Chief Information Security Officer provides strategic leadership and vision to strengthen Ameren’s security posture and promote resilience in an evolving threat landscape.

Item 2. Properties

Properties — owned and leased real estate

11 edited+2 added−2 removed5 unchanged
Biggest changeCharles County, Missouri 972,000 Total coal 3,344,000 Nuclear Callaway (d) Callaway County, Missouri 1,194,000 Hydroelectric Osage (d) Lakeside, Missouri 235,000 Keokuk Keokuk, Iowa 148,000 Total hydroelectric 383,000 Pumped-storage Taum Sauk (d) Reynolds County, Missouri 440,000 Wind High Prairie Adair and Schuyler Counties, Missouri 400,000 Atchison Atchison County, Missouri 298,800 Total wind 698,800 Solar Huck Finn (e) Audrain and Ralls Counties, Missouri 200,000 Boomtown White County, Illinois 150,000 Cass County Cass County, Illinois 150,000 Other Solar (f) Various 15,300 Total solar 515,300 Natural gas (CTs) Audrain Audrain County, Missouri 608,000 Venice (g) Venice, Illinois 487,000 Goose Creek (g) Piatt County, Illinois 438,000 Pinckneyville (g) Pinckneyville, Illinois 316,000 Raccoon Creek (g) Clay County, Illinois 304,000 Kinmundy (g) Kinmundy, Illinois 210,000 Peno Creek Bowling Green, Missouri 172,000 Total natural gas 2,535,000 Oil (CTs) Fairgrounds (h) Jefferson City, Missouri 55,000 Mexico (h) Mexico, Missouri 54,000 Moberly (h) Moberly, Missouri 54,000 Moreau (h) Jefferson City, Missouri 54,000 Total oil 217,000 Methane gas (CT) Maryland Heights Maryland Heights, Missouri 9,000 Total Ameren Missouri 9,336,100 Ameren Illinois: Solar East St.
Biggest changeCharles County, Missouri 972 Total coal 3,344 Nuclear Callaway (d) Callaway County, Missouri 1,194 Hydroelectric Osage (d) Lakeside, Missouri 235 Keokuk Keokuk, Iowa 148 Total hydroelectric 383 Pumped-storage Taum Sauk (d) Reynolds County, Missouri 440 Wind High Prairie Adair and Schuyler Counties, Missouri 400 Atchison Atchison County, Missouri 299 Total wind 699 Solar Split Rail (e) Warren County, Missouri 300 Huck Finn (f) Audrain and Ralls Counties, Missouri 200 Boomtown White County, Illinois 153 Cass County Cass County, Illinois 150 Vandalia (f) Audrain County, Missouri 50 Bowling Green (e) Pike County, Missouri 50 Other Solar (g) Various 15 Total solar 918 Natural gas (CTs) Audrain Audrain County, Missouri 608 Venice (h) Venice, Illinois 486 Goose Creek (h) Piatt County, Illinois 438 Pinckneyville (h) Pinckneyville, Illinois 316 Raccoon Creek (h) Clay County, Illinois 304 Kinmundy (h) Kinmundy, Illinois 210 Peno Creek Bowling Green, Missouri 172 Total natural gas 2,534 Oil (CTs) Fairgrounds (i) Jefferson City, Missouri 55 Mexico (i) Mexico, Missouri 54 Moberly (i) Moberly, Missouri 54 Moreau (i) Jefferson City, Missouri 54 Total oil 217 Methane gas (CT) Maryland Heights Maryland Heights, Missouri 9 Total Ameren Missouri 9,738 Ameren Illinois: Solar East St.
Substantially all of the properties and plant of Ameren Missouri and Ameren Illinois are subject to the liens of the indentures securing their respective mortgage bonds. Ameren Missouri operates the Huck Finn Energy Center located in Audrain and Ralls Counties, Missouri.
Substantially all of the properties and plant of Ameren Missouri and Ameren Illinois are subject to the liens of the indentures securing their respective mortgage bonds. Ameren Missouri operates the Huck Finn Energy Center located in Audrain and Ralls Counties, Missouri, and operates the Vandalia Energy Center located in Audrain County, Missouri.
The exceptions as of December 31, 2024 are as follows: • Certain property is situated on lands occupied under leases, easements, franchises, licenses, or permits.
The exceptions as of December 31, 2025 are as follows: • Certain property is situated on lands occupied under leases, easements, franchises, licenses, or permits.
Ameren Missouri has rights and obligations as the operator of the energy center under long-term agreements with Audrain and Ralls Counties. Under the terms of these agreements, Ameren Missouri is responsible for all operation and maintenance for the energy center.
Ameren Missouri has rights and obligations as the operator of the energy centers under long-term agreements with Audrain and Ralls Counties. Under the terms of these agreements, Ameren Missouri is responsible for all operation and maintenance for both energy centers.
This capacity is only attainable when wind/solar conditions are sufficiently available. The on-demand capability for wind and solar units is zero. (b) The Labadie Energy Center is scheduled to retire 1,186,000 kilowatts by 2036 and 1,186,000 kilowatts by 2042.
This capacity is only attainable when wind/solar conditions are sufficiently available. The on-demand capability for wind and solar units is zero. (b) The Labadie Energy Center is scheduled to retire 1,186 megawatts by 2036 and 1,186 megawatts by 2042. (c) The Sioux Energy Center is scheduled to retire by 2032.
Louis I East St. Louis, Illinois 2,500 East St. Louis II East St. Louis, Illinois 1,900 Total Ameren 9,340,500 (a) Net kilowatt capability, except for wind and solar generating facilities, is the generating capacity available for dispatch from the energy center into the electric transmission grid. Capability for wind and solar generating facilities represents nameplate capacity.
Louis I East St. Louis, Illinois 2 East St. Louis II East St. Louis, Illinois 2 Total Ameren 9,742 (a) Net megawatt capability, except for wind and solar generating facilities, is the generating capacity available for dispatch from the energy center into the electric transmission grid. Capability for wind and solar generating facilities represents nameplate capacity.
(h) The Fairgrounds, Mexico, Moberly, and Moreau energy centers are scheduled to retire by the end of 2029. 32 Table of Contents The following table presents in-service electric and natural gas utility-related properties for Ameren Missouri and Ameren Illinois as of December 31, 2024: Ameren Missouri Ameren Illinois Circuit miles of electric transmission lines (a) 3,114 4,786 Circuit miles of electric distribution lines 34,319 46,299 Percentage of circuit miles of electric distribution lines underground 25 % 16 % Miles of natural gas transmission and distribution mains 3,558 18,750 Underground natural gas storage fields — 12 Total working capacity of underground natural gas storage fields in billion cubic feet — 24 (a) ATXI owns 561 circuit miles of electric transmission lines not reflected in this table.
(i) The Fairgrounds, Mexico, Moberly, and Moreau energy centers are scheduled to retire by the end of 2029. 33 Table of Contents The following table presents in-service electric and natural gas utility-related properties for Ameren Missouri and Ameren Illinois as of December 31, 2025: Ameren Missouri Ameren Illinois Circuit miles of electric transmission lines (a) 3,114 4,804 Circuit miles of electric distribution lines 34,287 46,054 Percentage of circuit miles of electric distribution lines underground 25 % 16 % Miles of natural gas transmission and distribution mains 3,584 18,758 Underground natural gas storage fields — 12 Total working capacity of underground natural gas storage fields in billion cubic feet — 24 (a) ATXI owns 561 circuit miles of electric transmission lines not reflected in this table.
See also Note 5 – Long-term Debt and Equity Financings and Note 14 – Commitments and Contingencies under Part II, Item 8, of this report. 31 Table of Contents The following table shows the anticipated capability of our energy centers at the time of the expected 2025 peak summer electrical demand for all energy centers owned as of December 31, 2024: Primary Fuel Source Energy Center Location Net Kilowatt Capability (a) Ameren Missouri: Coal Labadie (b) Franklin County, Missouri 2,372,000 Sioux (c) St.
See also Note 14 – Commitments and Contingencies under Part II, Item 8, of this report. 32 Table of Contents The following table shows the anticipated capability of our energy centers at the time of the expected 2026 peak summer electrical demand for all energy centers owned as of December 31, 2025, except as otherwise noted below: Primary Fuel Source Energy Center Location Net Megawatt Capability (a) Ameren Missouri: Coal Labadie (b) Franklin County, Missouri 2,372 Sioux (c) St.
The agreements are scheduled to expire in December 2059, at which time the property, plant, and equipment will become subject to the lien of the Ameren Missouri mortgage bond indenture.
The Vandalia Energy Center agreement is scheduled to expire in December 2050, and the Huck Finn Energy Center agreements are scheduled to expire in December 2059, at which time the property, plant, and equipment will become subject to the lien of the Ameren Missouri mortgage bond indenture.
(g) The Venice Energy Center is scheduled to retire by the end of 2029 and the Goose Creek, Pinckneyville, Raccoon Creek, and Kinmundy energy centers are scheduled to retire by the end of 2039. See Illinois Emissions Standards in Note 14 – Commitments and Contingencies under Part II, Item 8, of this report.
See Illinois Emissions Standards in Note 14 – Commitments and Contingencies under Part II, Item 8, of this report.
See Note 2 – Rate and Regulatory Matters under Part II, Item 8, of this report for additional information on Ameren Missouri’s request to extend the retirement date of the Sioux Energy Center. (d) The operating licenses for the Callaway, Osage, and Taum Sauk energy centers expire in 2044, 2047, and 2044, respectively.
(d) The operating licenses for the Callaway, Osage, and Taum Sauk energy centers are scheduled to expire in 2044, 2047, and 2044, respectively. (e) In February 2026, Ameren Missouri acquired the Split Rail Solar Project.
Removed
(c) Ameren Missouri plans to extend the retirement date of the Sioux Energy Center from 2030 to 2032, which is subject to the approval of a change in depreciable lives of the energy center’s assets by the MoPSC in Ameren Missouri’s 2024 electric service regulatory rate review.
Added
The Bowling Green and Split Rail solar projects are expected to be placed in-service in the first quarter of 2026 and in the second quarter of 2026, respectively, before 2026 peak summer electrical demand. (f) There were economic development arrangements applicable to this solar energy center, as discussed below.
Removed
(e) There were economic development arrangements applicable to this solar energy center, as discussed below. (f) Includes 10 solar energy centers that each have a nameplate capacity of 6,000 kilowatts or less.
Added
(g) Includes 10 solar energy centers that each have a nameplate capacity of 6 megawatts or less. (h) The Venice Energy Center is scheduled to retire by the end of 2029 and the Goose Creek, Pinckneyville, Raccoon Creek, and Kinmundy energy centers are scheduled to retire by the end of 2039.

Item 3. Legal Proceedings

Legal Proceedings — active lawsuits and investigations

1 edited+0 added−0 removed3 unchanged
Biggest changePursuant to Item 103(c)(3)(iii) of Regulation S-K, our policy is to disclose environmental proceedings to which a governmental entity is a party if we reasonably believe such proceedings will result in monetary sanctions of $1 million or more. ITEM 4. MINE SAFETY DISCLOSURES Not applicable. 33 Table of Contents PART II
Biggest changePursuant to Item 103(c)(3)(iii) of Regulation S-K, our policy is to disclose environmental proceedings to which a governmental entity is a party if we reasonably believe such proceedings will result in monetary sanctions of $1 million or more.

Item 5. Market for Registrant's Common Equity

Market for Common Equity — stock, dividends, buybacks

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Biggest changeComparison of Five-Year Cumulative Return 34 Table of Contents December 31, 2019 2020 2021 2022 2023 2024 Ameren (AEE) $ 100.00 $ 104.27 $ 122.09 $ 125.19 $ 105.07 $ 133.96 S&P 500 Index 100.00 118.39 152.34 124.73 157.48 196.85 S&P 500 Utility Index 100.00 100.52 118.29 120.14 111.63 137.79 Philadelphia Utility Index 100.00 102.72 121.46 122.25 111.05 134.24 Ameren management cautions that the stock price performance shown above should not be considered indicative of future stock price performance.
Biggest changeComparison of Five-Year Cumulative Return 37 Table of Contents December 31, 2020 2021 2022 2023 2024 2025 Ameren (AEE) $ 100.00 $ 117.09 $ 120.06 $ 100.76 $ 128.48 $ 148.15 S&P 500 Index 100.00 128.68 105.36 133.03 166.28 195.98 S&P 500 Utility Index 100.00 117.67 119.51 111.05 137.07 159.06 Philadelphia Utility Index 100.00 118.24 119.01 108.10 130.68 153.04 Ameren management cautions that the stock price performance shown above should not be considered indicative of future stock price performance.
Ameren holds all outstanding common stock of Ameren Missouri and Ameren Illinois. Purchases of Equity Securities Ameren Corporation, Ameren Missouri, and Ameren Illinois did not purchase any equity securities reportable under Item 703 of Regulation S-K during the period from October 1, 2024, to December 31, 2024.
Ameren holds all outstanding common stock of Ameren Missouri and Ameren Illinois. Purchases of Equity Securities Ameren Corporation, Ameren Missouri, and Ameren Illinois did not purchase any equity securities reportable under Item 703 of Regulation S-K during the period from October 1, 2025, to December 31, 2025.
Performance Graph The following graph shows Ameren’s cumulative TSR during the five years ended December 31, 2024. The graph also shows the cumulative total returns of the S&P 500 Index, S&P 500 Utility Index, and the Philadelphia Utility Index. The S&P 500 Utility Index and the Philadelphia Utility Index are market capitalization-weighted indices of U.S. public utility companies.
Performance Graph The following graph shows Ameren’s cumulative TSR during the five years ended December 31, 2025. The graph also shows the cumulative total returns of the S&P 500 Index, S&P 500 Utility Index, and the Philadelphia Utility Index. The S&P 500 Utility Index and the Philadelphia Utility Index are market capitalization-weighted indices of U.S. public utility companies.
The comparison assumes that $100 was invested on December 31, 2019, in Ameren common stock and in each of the indices shown and that all of the dividends were reinvested.
The comparison assumes that $100 was invested on December 31, 2020, in Ameren common stock and in each of the indices shown and that all of the dividends were reinvested.
ITEM 5. MARKET FOR REGISTRANTS’ COMMON EQUITY, RELATED STOCKHOLDER MATTERS AND ISSUER PURCHASES OF EQUITY SECURITIES Ameren’s common stock is listed on the NYSE (ticker symbol: AEE). Ameren common shareholders of record totaled 33,414 on January 31, 2025. There is no trading market for the common stock of Ameren Missouri and Ameren Illinois.
ITEM 5. MARKET FOR REGISTRANTS’ COMMON EQUITY, RELATED STOCKHOLDER MATTERS AND ISSUER PURCHASES OF EQUITY SECURITIES Ameren’s common stock is listed on the NYSE (ticker symbol: AEE). Ameren common shareholders of record totaled 31,149 on January 30, 2026. There is no trading market for the common stock of Ameren Missouri and Ameren Illinois.

Item 6. [Reserved]

Selected Financial Data — reserved (removed by SEC in 2021)

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Biggest changeOther Income, Net 126 Note 7. Derivative Financial Instruments 126 Note 8. Fair Value Measurements 128 Note 9. Callaway Energy Center 131 Note 10. Retirement Benefits 134 Note 11. Stock-based Compensation 140 Note 12. Income Taxes 142 Note 13. Related-party Transactions 145 Note 14. Commitments and Contingencies 148 Note 15. Supplemental Information 152 Note 16. Segment Information 155 Item 9.
Biggest changeOther Income, Net 125 Note 7. Derivative Financial Instruments 125 Note 8. Fair Value Measurements 127 Note 9. Callaway Energy Center 130 Note 10. Retirement Benefits 133 Note 11. Stock-based Compensation 139 Note 12. Income Taxes 141 Note 13. Related-party Transactions 145 Note 14. Commitments and Contingencies 149 Note 15. Supplemental Information 152 Note 16. Segment Information 156 Item 9.
Financial Statements and Supplementary Data 80 Ameren Corporation 86 Union Electric 90 Ameren Illinois 94 Note 1. Summary of Significant Accounting Policies 98 Note 2. Rate and Regulatory Matters 103 Note 3. Property, Plant, and Equipment, Net 115 Note 4. Short-term Debt and Liquidity 116 Note 5. Long-term Debt and Equity Financings 119 Note 6.
Financial Statements and Supplementary Data 80 Ameren Corporation 86 Union Electric 90 Ameren Illinois 94 Note 1. Summary of Significant Accounting Policies 98 Note 2. Rate and Regulatory Matters 103 Note 3. Property, Plant, and Equipment, Net 114 Note 4. Short-term Debt and Liquidity 115 Note 5. Long-term Debt and Equity Financings 118 Note 6.
Changes in and Disagreements with Accountants on Accounting and Financial Disclosure 161 Item 9A. Controls and Procedures 162 Item 9B. Other Information 162
Changes in and Disagreements with Accountants on Accounting and Financial Disclosure 162 Item 9A. Controls and Procedures 163 Item 9B. Other Information 163
Item 6. (Reserved) 35 Item 7. Management’s Discussion and Analysis of Financial Condition and Results of Operations 35 Overview 36 Results of Operations 41 Liquidity and Capital Resources 57 Outlook 67 Regulatory Matters 73 Accounting Matters 73 Item 7A. Quantitative and Qualitative Disclosures About Market Risk 77 Item 8.
Item 6. (Reserved) 38 Item 7. Management’s Discussion and Analysis of Financial Condition and Results of Operations 38 Overview 39 Results of Operations 42 Liquidity and Capital Resources 57 Outlook 67 Regulatory Matters 73 Accounting Matters 73 Item 7A. Quantitative and Qualitative Disclosures About Market Risk 77 Item 8.

Item 7. Management's Discussion & Analysis

Management's Discussion & Analysis (MD&A) — revenue / margin commentary

227 edited+113 added−144 removed100 unchanged
Biggest changeFor additional details regarding the Ameren Companies’ results of operations, including explanations of Operating Revenues for both Electric Revenues and Natural Gas Revenues; Fuel and Purchased Power Expenses; Other Operations and Maintenance Expenses; Depreciation and Amortization Expenses; Taxes Other Than Income Taxes; Other Income, Net; Interest Charges; and Income Taxes, see the major headings below. 43 Table of Contents Below is Ameren’s table of income statement components by segment for the years ended December 31, 2024 and 2023: 2024 Ameren Missouri Ameren Illinois Electric Distribution Ameren Illinois Natural Gas Ameren Transmission Other / Intersegment Eliminations Ameren Electric revenues $ 3,847 $ 2,089 $ — $ 781 $ (177) $ 6,540 Natural gas revenues 146 — 938 — (1) 1,083 Fuel and purchased power (1,071) (740) — — 130 (1,681) Natural gas purchased for resale (60) — (260) — — (320) Other operations and maintenance expenses (1,050) (619) (230) (70) — (1,969) Depreciation and amortization (917) (369) (129) (167) (8) (1,590) Taxes other than income taxes (372) (75) (78) (9) (13) (547) Operating income (loss) 523 286 241 535 (69) 1,516 Other income, net 196 97 27 26 71 417 Interest charges (244) (98) (63) (117) (141) (663) Income (taxes) benefit 87 (50) (56) (120) 56 (83) Net income (loss) 562 235 149 324 (83) 1,187 Noncontrolling interests – preferred stock dividends (3) (1) — (1) — (5) Net income (loss) attributable to Ameren common shareholders $ 559 $ 234 $ 149 $ 323 $ (83) $ 1,182 2023 Electric revenues $ 3,694 $ 2,218 $ — $ 677 $ (150) $ 6,439 Natural gas revenues 165 — 897 — (1) 1,061 Fuel and purchased power (997) (933) — — 118 (1,812) Natural gas purchased for resale (79) — (276) — — (355) Other operations and maintenance expenses (1,003) (532) (237) (60) (34) (1,866) Depreciation and amortization (783) (351) (108) (138) (7) (1,387) Taxes other than income taxes (360) (75) (67) (8) (12) (522) Operating income (loss) 637 327 209 471 (86) 1,558 Other income, net 130 103 30 28 57 348 Interest charges (227) (89) (55) (96) (99) (566) Income (taxes) benefit 8 (82) (50) (106) 47 (183) Net income (loss) 548 259 134 297 (81) 1,157 Noncontrolling interests – preferred stock dividends (3) (1) — (1) — (5) Net income (loss) attributable to Ameren common shareholders $ 545 $ 258 $ 134 $ 296 $ (81) $ 1,152 44 Table of Contents Below is Ameren Illinois’ table of income statement components by segment for the years ended December 31, 2024 and 2023: 2024 Ameren Illinois Electric Distribution Ameren Illinois Natural Gas Ameren Illinois Transmission Other / Intersegment Eliminations Ameren Illinois Electric revenues $ 2,089 $ — $ 564 $ (119) $ 2,534 Natural gas revenues — 938 — — 938 Purchased power (740) — — 119 (621) Natural gas purchased for resale — (260) — — (260) Other operations and maintenance expenses (619) (230) (57) — (906) Depreciation and amortization (369) (129) (121) — (619) Taxes other than income taxes (75) (78) (4) — (157) Operating income 286 241 382 — 909 Other income, net 97 27 23 — 147 Interest charges (98) (63) (80) — (241) Income taxes (50) (56) (87) — (193) Net income 235 149 238 — 622 Preferred stock dividends (1) — (1) — (2) Net income attributable to common shareholder $ 234 $ 149 $ 237 $ — $ 620 2023 Electric revenues $ 2,218 $ — $ 480 $ (113) $ 2,585 Natural gas revenues — 897 — — 897 Purchased power (933) — — 113 (820) Natural gas purchased for resale — (276) — — (276) Other operations and maintenance expenses (532) (237) (49) — (818) Depreciation and amortization (351) (108) (97) — (556) Taxes other than income taxes (75) (67) (4) — (146) Operating income 327 209 330 — 866 Other income, net 103 30 23 — 156 Interest charges (89) (55) (60) — (204) Income taxes (82) (50) (77) — (209) Net income 259 134 216 — 609 Preferred stock dividends (1) — (1) — (2) Net income attributable to common shareholder $ 258 $ 134 $ 215 $ — $ 607 45 Table of Contents Operating Revenues The following table presents the increases (decreases) by Ameren segment for electric and natural gas revenues in 2024, compared with 2023: 2024 versus 2023 Ameren Missouri Ameren Illinois Electric Distribution Ameren Illinois Natural Gas Ameren Transmission (a) Other /Intersegment Eliminations Ameren Electric revenue change: Base rates (estimate) (b) $ 62 $ 14 $ — $ 89 $ — $ 165 Effect of weather (estimate) (c) 3 — — — — 3 Retail sales volumes and changes in customer usage patterns (excluding the estimated effects of weather and MEEIA) 27 — — — — 27 Customer charges 2 — — — — 2 Rush Island Energy Center base rate revenue deferral (13) — — — — (13) MEEIA 2019 performance incentives 1 — — — — 1 Off-system sales, capacity, transmission, and FAC revenues, net 96 — — — — 96 Recovery of power restoration efforts provided to other utilities 1 3 — — — 4 Ameren Illinois energy-efficiency program investment revenues — 21 — — — 21 Electric deferred income tax adjustment (d) — (23) — — — (23) Other 6 4 — 15 (15) 10 Cost recovery mechanisms – offset in fuel and purchased power (e) (54) (193) — — (12) (259) Other cost recovery mechanisms (f) 22 45 — — — 67 Total electric revenue change $ 153 $ (129) $ — $ 104 $ (27) $ 101 Natural gas revenue change: Base rates (estimate) $ — $ — $ 47 $ — $ — $ 47 Sales volume (excluding the estimated effects of weather) 2 — — — — 2 Effect of weather (estimate) (c) 1 — — — — 1 Other — — 3 — — 3 Cost recovery mechanisms – offset in natural gas purchased for resale (e) (20) — (16) — — (36) Other cost recovery mechanisms (f) (2) — 7 — — 5 Total natural gas revenue change $ (19) $ — $ 41 $ — $ — $ 22 (a) Includes an increase in transmission revenues of $84 million in 2024, compared with 2023, at Ameren Illinois.
Biggest changeBelow is Ameren’s table of income statement components by segment for the years ended December 31, 2025 and 2024: 2025 Ameren Missouri Ameren Illinois Electric Distribution Ameren Illinois Natural Gas Ameren Transmission Other / Intersegment Eliminations Ameren Electric revenues $ 4,631 $ 2,399 $ — $ 862 $ (224) $ 7,668 Natural gas revenues 164 — 968 — (1) 1,131 Fuel and purchased power (1,538) (941) — — 173 (2,306) Natural gas purchased for resale (65) — (283) — — (348) Other operations and maintenance expenses (1,029) (656) (233) (74) 18 (1,974) Depreciation and amortization (860) (373) (128) (199) (8) (1,568) Taxes other than income taxes (393) (82) (82) (9) (11) (577) Operating income (loss) 910 347 242 580 (53) 2,026 Other income, net 180 89 19 24 35 347 Interest charges (297) (107) (65) (120) (187) (776) Income (taxes) benefit (43) (47) (38) (68) 60 (136) Net income (loss) 750 282 158 416 (145) 1,461 Noncontrolling interests – preferred stock dividends (3) (1) — (1) — (5) Net income (loss) attributable to Ameren common shareholders $ 747 $ 281 $ 158 $ 415 $ (145) $ 1,456 2024 Electric revenues $ 3,847 $ 2,089 $ — $ 781 $ (177) $ 6,540 Natural gas revenues 146 — 938 — (1) 1,083 Fuel and purchased power (1,071) (740) — — 130 (1,681) Natural gas purchased for resale (60) — (260) — — (320) Other operations and maintenance expenses (1,050) (619) (230) (70) — (1,969) Depreciation and amortization (917) (369) (129) (167) (8) (1,590) Taxes other than income taxes (372) (75) (78) (9) (13) (547) Operating income (loss) 523 286 241 535 (69) 1,516 Other income, net 196 97 27 26 71 417 Interest charges (244) (98) (63) (117) (141) (663) Income (taxes) benefit 87 (50) (56) (120) 56 (83) Net income (loss) 562 235 149 324 (83) 1,187 Noncontrolling interests – preferred stock dividends (3) (1) — (1) — (5) Net income (loss) attributable to Ameren common shareholders $ 559 $ 234 $ 149 $ 323 $ (83) $ 1,182 44 Table of Contents Below is Ameren Illinois’ table of income statement components by segment for the years ended December 31, 2025 and 2024: 2025 Ameren Illinois Electric Distribution Ameren Illinois Natural Gas Ameren Illinois Transmission Other / Intersegment Eliminations Ameren Illinois Electric revenues $ 2,399 $ — $ 637 $ (160) $ 2,876 Natural gas revenues — 968 — — 968 Purchased power (941) — — 160 (781) Natural gas purchased for resale — (283) — — (283) Other operations and maintenance expenses (656) (233) (56) — (945) Depreciation and amortization (373) (128) (151) — (652) Taxes other than income taxes (82) (82) (5) — (169) Operating income 347 242 425 — 1,014 Other income, net 89 19 28 — 136 Interest charges (107) (65) (88) — (260) Income taxes (47) (38) (68) — (153) Net income 282 158 297 — 737 Preferred stock dividends (1) — (1) — (2) Net income attributable to common shareholder $ 281 $ 158 $ 296 $ — $ 735 2024 Electric revenues $ 2,089 $ — $ 564 $ (119) $ 2,534 Natural gas revenues — 938 — — 938 Purchased power (740) — — 119 (621) Natural gas purchased for resale — (260) — — (260) Other operations and maintenance expenses (619) (230) (57) — (906) Depreciation and amortization (369) (129) (121) — (619) Taxes other than income taxes (75) (78) (4) — (157) Operating income 286 241 382 — 909 Other income, net 97 27 23 — 147 Interest charges (98) (63) (80) — (241) Income taxes (50) (56) (87) — (193) Net income 235 149 238 — 622 Preferred stock dividends (1) — (1) — (2) Net income attributable to common shareholder $ 234 $ 149 $ 237 $ — $ 620 45 Table of Contents Operating Revenues The following table presents the increases (decreases) by Ameren segment for electric and natural gas revenues in 2025, compared with 2024: 2025 versus 2024 Ameren Missouri Ameren Illinois Electric Distribution Ameren Illinois Natural Gas Ameren Transmission (a) Other /Intersegment Eliminations Ameren Electric revenue change: Base rates (estimate) (b) $ 249 $ 96 $ — $ 81 $ — $ 426 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 RESRAM (d) (23) — — — — (23) Rush Island Energy Center base rate revenue deferral (13) — — — — (13) Securitized utility tariff bond surcharges 46 — — — — 46 Off-system sales, capacity, transmission, and FAC revenues, net 452 — — — — 452 Ameren Illinois energy-efficiency program investment revenues — 12 — — — 12 Other 4 18 — — (6) 16 Cost recovery mechanisms – offset in fuel and purchased power (e) (12) 201 — — (41) 148 Other cost recovery mechanisms (f) (5) (17) — — — (22) Total electric revenue change $ 784 $ 310 $ — $ 81 $ (47) $ 1,128 Natural gas revenue change: Base rates (estimate) $ 9 $ — $ 4 $ — $ — $ 13 Effect of weather (estimate) (c) 12 — — — — 12 Other 1 — — — — 1 Cost recovery mechanisms – offset in natural gas purchased for resale (e) (4) — 23 — — 19 Other cost recovery mechanisms (f) — — 3 — — 3 Total natural gas revenue change $ 18 $ — $ 30 $ — $ — $ 48 (a) Includes an increase in transmission revenues of $73 million in 2025, compared with 2024, at Ameren Illinois.
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.
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.
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. 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 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.
We record a loss contingency when it is probable that a liability has been incurred and the amount of the loss can be reasonably estimated. • Estimating financial impact of events • Estimating likelihood of various potential outcomes • Regulatory and political environments and requirements • Outcome of legal proceedings, settlements, or other factors • Changes in regulation, legislation, expected scope of work, technology, or timing of environmental remediation Basis for Judgment The determination of a loss contingency requires significant judgment as to the expected outcome of the contingency in future periods.
We record a loss contingency when it is probable that a liability has been incurred and the amount of the loss can be reasonably estimated. • Estimating expected financial impact of future events • Estimating likelihood of various potential outcomes • Regulatory and political environments and requirements • Outcome of legal proceedings, settlements, or other factors • Changes in regulation, legislation, expected scope of work, technology, or timing of environmental remediation Basis for Judgment The determination of a loss contingency requires significant judgment as to the expected outcome of the contingency in future periods.
See Note 12 – Income Taxes under Part II, Item 8, of this report. • Changes in business, industry, laws, technology, or economic and market conditions affecting forecasted financial condition and/or results of operations • Estimates of the amount and character of future taxable income and forecasted use of our tax credit carryforwards • Enacted tax rates applicable to taxable income in years in which temporary differences are recovered or settled • Effectiveness of implementing tax planning strategies • Changes in income tax laws, including amounts subject to income tax, and the regulatory treatment of any tax reform changes • Results of audits and examinations by taxing authorities • Ability to forecast production and investment tax credits 75 Table of Contents Basis for Judgment The reporting of tax-related assets and liabilities requires the use of estimates and significant management judgment.
See Note 12 – Income Taxes under Part II, Item 8, of this report. • Changes in business, industry, laws, technology, or economic and market conditions affecting forecasted financial condition and/or results of operations • Estimates of the amount and character of future taxable income and forecasted use of our tax credit carryforwards • Enacted tax rates applicable to taxable income in years in which temporary differences are recovered or settled • Effectiveness of implementing tax planning strategies • Changes in income tax laws, including amounts subject to income tax, and the regulatory treatment of any tax reform changes • Results of audits and examinations by taxing authorities • Ability to forecast and transfer production and investment tax credits 75 Table of Contents Basis for Judgment The reporting of tax-related assets and liabilities requires the use of estimates and significant management judgment.
The following table presents the principal credit ratings of the Ameren Companies by Moody’s and S&P effective on the date of this report: Moody’s S&P Ameren: Issuer/corporate credit rating Baa1 BBB+ Senior unsecured debt Baa1 BBB Commercial paper P-2 A-2 Ameren Missouri: Issuer/corporate credit rating Baa1 BBB+ Senior debt A2 A Senior unsecured debt Baa1 Not Rated Commercial paper P-2 A-2 AMF securitized utility tariff bonds Aaa AAA Ameren Illinois: Issuer/corporate credit rating A3 BBB+ Senior debt A1 A Senior unsecured debt A3 BBB+ Commercial paper P-2 A-2 ATXI: Issuer credit rating A2 Not Rated Senior unsecured debt A2 Not Rated A credit rating is not a recommendation to buy, sell, or hold securities.
The following table presents the principal credit ratings of the Ameren Companies by Moody’s and S&P effective on the date of this report: Moody’s S&P Ameren: Issuer/corporate credit rating Baa1 BBB+ Senior unsecured debt Baa1 BBB Commercial paper P-2 A-2 Ameren Missouri: Issuer/corporate credit rating Baa1 BBB+ Secured debt A2 A Commercial paper P-2 A-2 AMF securitized utility tariff bonds Aaa AAA Ameren Illinois: Issuer/corporate credit rating A3 BBB+ Secured debt A1 A Commercial paper P-2 A-2 ATXI: Issuer credit rating A2 Not Rated Senior unsecured debt A2 Not Rated A credit rating is not a recommendation to buy, sell, or hold securities.
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 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.
At each period end, and as new developments occur, management reevaluates its tax positions. Additional interpretations, regulations, amendments, or technical corrections related to the federal income tax code as a result of the IRA, may impact the estimates for income taxes discussed above.
At each period end, and as new developments occur, management reevaluates its tax positions. Additional interpretations, regulations, amendments, or technical corrections related to the federal income tax code as a result of the OBBBA and the IRA, may impact the estimates for income taxes discussed above.
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.
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 battery storage.
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.
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.
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.
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.
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.
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.
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 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 $800 million of long-term debt maturities at Ameren (parent) and Ameren Missouri, and to fund, in part, capital expenditures.
Under the MYRP discussed below, Ameren Illinois’ 2025 electric distribution service revenues will be based on its 2025 actual recoverable costs, 2025 year-end rate base, and an ROE of 8.72%, as adjusted for any performance incentives or penalties, provided the actual revenue requirement does not exceed the reconciliation cap.
Under the MYRP discussed below, Ameren Illinois’ 2026 electric distribution service revenues will be based on its 2026 actual recoverable costs, 2026 year-end rate base, and an ROE of 8.72%, as adjusted for any performance incentives or penalties, provided the actual revenue requirement does not exceed the reconciliation cap.
Rate Base ($ in billions) (a) Regulatory Frameworks (c) Electric Customer Rates (f) Segment Regulatory Framework Ameren Transmission Formula ratemaking with initial rates based on a future test year Allowed ROE of 10.48% Ameren Illinois Electric Distribution Future test year ratemaking under an MYRP (d) and RBA Allowed ROE of 8.72% (e) Ameren Illinois Natural Gas Future test year ratemaking and PGA and VBA Allowed ROE of 9.44% Ameren Missouri Historical test year ratemaking and PISA, RESRAM, FAC, MEEIA, PGA Allowed ROE is not specified (a) Reflects year-end rate base except for Ameren Transmission, which is average rate base.
Rate Base ($ in billions) (a) Regulatory Frameworks (c) Electric Customer Rates (g) Segment Regulatory Framework Ameren Transmission Formula ratemaking with initial rates based on a future test year Allowed ROE of 10.48% Ameren Illinois Electric Distribution Future test year ratemaking under an MYRP (d) and RBA Allowed ROE of 8.72% (e) Ameren Illinois Natural Gas Future test year ratemaking and PGA and VBA Allowed ROE of 9.60% Ameren Missouri Historical test year ratemaking (f) and PISA, RESRAM, FAC, MEEIA, PGA Allowed ROE is not specified (a) Reflects year-end rate base except for Ameren Transmission, which is average rate base.
We have natural gas 41 Table of Contents cost recovery mechanisms for our Illinois and Missouri natural gas distribution businesses, a purchased power cost recovery mechanism for Ameren Illinois’ electric distribution business, and a FAC for Ameren Missouri’s electric business. We employ various risk management strategies to reduce our exposure to commodity risk and other risks inherent in our business.
We have natural gas 42 Table of Contents cost recovery mechanisms for our Illinois and Missouri natural gas distribution businesses, a purchased power cost recovery mechanism for Ameren Illinois’ electric distribution business, and a FAC for Ameren Missouri’s electric business. We employ various risk management strategies to reduce our exposure to commodity risk and other risks inherent in our business.
Additionally, Ameren, Ameren Missouri, and Ameren Illinois have recorded AROs for retirement costs associated with asbestos removal and the disposal of certain transformers. See Note 15 – Supplemental Information under Part II, Item 8, of this report for the amount of AROs recorded at December 31, 2024.
Additionally, Ameren, Ameren Missouri, and Ameren Illinois have recorded AROs for retirement costs associated with asbestos removal and the disposal of certain transformers. See Note 15 – Supplemental Information under Part II, Item 8, of this report for the amount of AROs recorded at December 31, 2025.
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 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 66 Table of Contents 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.
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 2029.
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.
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 2029.
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.
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 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.
Changes in natural gas purchased for resale expenses are fully offset by corresponding changes in natural gas revenues under the PGA.
Changes in natural gas revenues under the PGA are fully offset by changes in natural gas purchased for resale expenses.
(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 . RESULTS OF OPERATIONS Our results of operations and financial position are affected by many factors.
(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 Our results of operations and financial position are affected by many factors.
Indebtedness Provisions and Other Covenants At December 31, 2024, 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.
Indebtedness Provisions and Other Covenants 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.
OUTLOOK Below are some key trends, events, and uncertainties that may reasonably affect our results of operations, financial condition, or liquidity, as well as our ability to achieve strategic and financial objectives, for 2025 and beyond.
OUTLOOK Below are some key trends, events, and uncertainties that may reasonably affect our results of operations, financial condition, or liquidity, as well as our ability to achieve strategic and financial objectives, for 2026 and beyond.
Using the 2023 revenue requirement as a starting point, the approved revenue requirements in the ICC’s December 2024 order represent a cumulative four-year increase of $309 million. Rate changes consistent with the December 2024 order became effective in December 2024.
Using the 2023 revenue requirement as a starting point, the approved revenue requirements in the ICC’s December 2024 order represent a cumulative four-year increase of $308 million. Rate changes consistent with the December 2024 order became effective in December 2024.
Our ultimate selection of the discount rate, health care trend rate, future compensation, and expected rate of return on pension and other postretirement benefit plan assets is based on our consistent application of assumption-setting methodologies, including our review of available historical, current, and projected rates, as applicable. 74 Table of Contents The following table reflects the sensitivity of Ameren’s pension and postretirement plans to potential changes in key assumptions for the year ended December 31, 2024: Pension Benefits Postretirement Benefits Net Periodic Benefit Cost Projected Pension Benefit Obligation Net Periodic Benefit Cost Projected Postretirement Benefit Obligation 0.25% decrease in discount rate $ 12 $ 115 $ 2 $ 21 0.25% decrease in return on assets 12 (a) 4 (a) (a) Not applicable.
Our ultimate selection of the discount rate, health care trend rate, future compensation, and expected rate of return on pension and other postretirement benefit plan assets is based on our consistent application of assumption-setting methodologies, including our review of available historical, current, and projected rates, as applicable. 74 Table of Contents The following table reflects the sensitivity of Ameren’s pension and postretirement plans to potential changes in key assumptions for the year ended December 31, 2025: Pension Benefits Postretirement Benefits Net Periodic Benefit Cost Projected Pension Benefit Obligation Net Periodic Benefit Cost Projected Postretirement Benefit Obligation 0.25% decrease in discount rate $ 12 $ 113 $ 2 $ 21 0.25% decrease in return on assets 11 (a) 4 (a) (a) Not applicable.
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 64 Table of Contents 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.
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.
The ROE determined by the ICC for each calendar year of the four-year period is subject to annual 68 Table of Contents 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.
We must use judgment to conclude that costs deferred as regulatory assets are probable of future recovery. We base our conclusion on certain factors including, but not limited to, orders issued by our regulatory commissions, enacted legislation, or historical experience, as well as discussions with legal counsel.
We must use judgment to conclude that costs deferred as regulatory assets are probable of future recovery. We base our conclusion on certain factors including, but not limited to, orders issued by our regulatory 73 Table of Contents commissions, enacted legislation, or historical experience, as well as discussions with legal counsel.
Discussion regarding our financial condition and results of operations for the year ended December 31, 2022, including comparisons with the year ended December 31, 2023, is included in Item 7 of our Form 10-K for the year ended December 31, 2023.
Discussion regarding our financial condition and results of operations for the year ended December 31, 2023, including comparisons with the year ended December 31, 2024, is included in Item 7 of our Form 10-K for the year ended December 31, 2024.
The cents per share variances above are presented based on the weighted-average basic shares outstanding in 2023 and do not reflect the impact of dilution on earnings per share, unless otherwise noted.
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.
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.
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 amounts above other than variances related to income taxes have been presented net of income taxes using Ameren’s 2024 blended federal and state statutory tax rate of 26%.
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%.
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.
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.
We believe this per share information helps readers to understand the impact of these factors on Ameren’s earnings per diluted share. 35 Table of Contents OVERVIEW Our core strategy is driven by the following three pillars, which allow us to capitalize on opportunities to benefit our customers, communities, shareholders, and the environment: 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 We invest in rate-regulated energy infrastructure and seek to earn competitive returns on our investments.
We believe this per share information helps readers to understand the impact of these factors on Ameren’s earnings per diluted share. 38 Table of Contents OVERVIEW 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 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.
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.
Ameren Illinois will reconcile its actual revenue requirement, as adjusted for certain cost variations, to ICC-approved electric distribution service rates on an annual basis, subject to a reconciliation cap. The reconciliation cap limits the annual adjustment to 105% of the annual revenue requirement approved by the ICC.
Ameren Illinois reconciles its actual revenue requirement, as adjusted for certain cost variations, to ICC-approved electric distribution service rates on an annual basis, subject to a reconciliation cap. The reconciliation cap limits the annual adjustment to 105% of the annual revenue requirement approved by the ICC.
If facts and circumstances lead us to 73 Table of Contents conclude that a recorded regulatory asset is no longer probable of recovery or that plant assets are probable of disallowance, we record a charge to earnings, which could be material.
If facts and circumstances lead us to conclude that a recorded regulatory asset is no longer probable of recovery or that plant assets are probable of disallowance, we record a charge to earnings, which could be material.
The individual or combined effects of compliance with existing and new environmental regulations could result in significant capital expenditures, increased operating costs, or the closure or alteration of operations at some of Ameren Missouri’s energy centers. Additionally, international agreements have in the past, and could again, lead to future federal or state legislation or regulations.
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.
While the ICC has approved a plan for Ameren Illinois to invest approximately $120 million per year in electric energy-efficiency programs through 2025, the ICC has the ability to reduce the amount of electric energy-efficiency savings goals in future program years if there are insufficient cost-effective programs available, which could reduce the investments in electric energy-efficiency programs.
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.
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.
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, 2025, for Ameren and Ameren Missouri.
The securitized tariff bondholders have no recourse to Ameren Missouri. (b) Ameren issued a total of 0.5 million and 0.6 million shares of common stock under its DRPlus and 401(k) plan in 2024 and 2023, respectively. (c) Excludes a $7 million and $7 million receivable at December 31, 2024 and 2023, respectively.
The securitized tariff bondholders have no recourse to Ameren Missouri. (b) Ameren issued a total of 0.4 million and 0.5 million shares of common stock under its DRPlus and 401(k) plan in 2025 and 2024, respectively. (c) Excludes a $7 million and $7 million receivable at December 31, 2025 and 2024, respectively.
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.
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.
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 .
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 .
See Note 2 – Rate and Regulatory Matters under Part II, Item 8, of this report for more information about our regulatory frameworks. Ameren Ameren’s cash provided by operating activities increased $199 million in 2024, compared with 2023.
See Note 2 – Rate and Regulatory Matters under Part II, Item 8, of this report for more information about our regulatory frameworks. Ameren Ameren’s cash provided by operating activities increased $590 million in 2025, compared with 2024.
(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.
“Cost recovery mechanisms — offset in electric revenue” decreased $54 million in 2024, compared with 2023, due to decreased amortization of costs previously deferred under the FAC. The changes to “Cost recovery mechanisms - offset in electric revenue” are fully offset by “Cost recovery mechanisms - offset in fuel and purchased power” in electric revenues.
“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. The changes to “Cost recovery mechanisms - offset in electric revenue” are fully offset by “Cost recovery mechanisms - offset in fuel and purchased power” in electric revenues.
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.
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 first set of second tranche projects also includes competitive bid projects.
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.
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.
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.
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.
The following table reflects the sensitivity of potential changes in key assumptions to Ameren Missouri’s Callaway Energy Center decommissioning obligation as of December 31, 2024: Change in Callaway Energy Center’s Key ARO Assumptions Increase (Decrease) to ARO Discount rate decreased by 0.10% $ 12 Cost escalation rate increased by 0.25% 28 Increase in the estimated decommissioning costs by 10% 47 Two-year deferral in timing of cash expenditures (31) Impact of New Accounting Pronouncements See Note 1 – Summary of Significant Accounting Policies under Part II, Item 8, of this report. 76 Table of Contents
The following table reflects the sensitivity of potential changes in key assumptions to Ameren Missouri’s Callaway Energy Center decommissioning obligation as of December 31, 2025: Change in Callaway Energy Center’s Key ARO Assumptions Increase (Decrease) to ARO Discount rate decreased by 0.25% $ 29 Cost escalation rate increased by 0.25% 27 Increase in the estimated decommissioning costs by 10% 48 Two-year deferral in timing of cash expenditures (33) Impact of New Accounting Pronouncements See Note 1 – Summary of Significant Accounting Policies under Part II, Item 8, of this report. 76 Table of Contents
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. 40 Table of Contents Ameren remains focused on strategic capital allocation.
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. 41 Table of Contents Ameren remains focused on strategic capital allocation.
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.
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 70 Table of Contents timing of projects; 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; new and/or changes in environmental regulations, including those related to CO 2 and other greenhouse gas emissions; energy prices; and demand; Ameren Missouri’s ability to obtain necessary rights-of-way, easements, and transmission interconnection agreements at an acceptable cost and in a timely fashion; the ability to earn an adequate return on invested capital; and the ability to raise capital on reasonable terms.
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 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 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; and demand; Ameren Missouri’s ability to obtain necessary rights-of-way, easements, and transmission interconnection agreements at an acceptable cost and in a timely fashion; the ability to earn an adequate return on invested capital; and the ability to raise capital on reasonable terms.
The 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. 49 Table of Contents Natural Gas Purchased for Resale The following table presents the increases (decreases) by Ameren segment for natural gas purchased for resale in 2024, compared with 2023: 2024 versus 2023 Ameren Missouri Ameren Illinois Electric Distribution Ameren Illinois Natural Gas Ameren Transmission Other /Intersegment Eliminations Ameren Natural gas purchased for resale change: Effect of weather (estimate) (a) $ 1 $ — $ — $ — $ — $ 1 Cost recovery mechanisms – offset in natural gas revenue (b) (20) — (16) — — (36) Total natural gas purchased for resale change $ (19) $ — $ (16) $ — $ — $ (35) (a) Represents the estimated variation resulting primarily from changes in heating degree-days on natural gas demand compared with the prior year; this variation is based on temperature readings from the National Oceanic and Atmospheric Administration weather stations at local airports in our service territories.
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. 49 Table of Contents Natural Gas Purchased for Resale The following table presents the increases (decreases) by Ameren segment for natural gas purchased for resale in 2025, compared with 2024: 2025 versus 2024 Ameren Missouri Ameren Illinois Electric Distribution Ameren Illinois Natural Gas Ameren Transmission Other /Intersegment Eliminations Ameren Natural gas purchased for resale change: Effect of weather (estimate) (a) $ 9 $ — $ — $ — $ — $ 9 Cost recovery mechanisms – offset in natural gas revenue (b) (4) — 23 — — 19 Total natural gas purchased for resale change $ 5 $ — $ 23 $ — $ — $ 28 (a) Represents the estimated variation resulting primarily from changes in heating degree-days on natural gas demand compared with the prior year; this variation is based on temperature readings from the National Oceanic and Atmospheric Administration weather stations at local airports in our service territories.
Based on expected rate base and the currently allowed 10.48% ROE, which includes a 50-basis-point incentive adder for participation in an RTO, the revenue requirements that will be included in 2025 rates for Ameren Illinois’ and ATXI’s electric transmission businesses are $643 million and $232 million, respectively.
Based on expected rate base and the currently allowed 10.48% ROE, which includes a 50-basis-point incentive adder for participation in an RTO, the revenue requirements that will be included in 2026 rates for Ameren Illinois’ and ATXI’s electric transmission businesses are $685 million and $265 million, respectively.
(d) Ameren issued 2.9 million and 3.2 million shares of common stock under the ATM program in 2024 and 2023, respectively. (e) Excludes 0.2 million and 0.5 million shares of common stock valued at $16 million and $40 million issued for no cash consideration in connection with stock-based compensation in 2024 and 2023, respectively.
(d) Ameren issued 5.8 million and 2.9 million shares of common stock under the ATM program in 2025 and 2024, respectively. (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.
Ameren Missouri Ameren Illinois Natural Gas Other/Intersegment Eliminations Ameren Illinois Electric Distribution Ameren Transmission Ameren Other operations and maintenance expenses increased $103 million in 2024, compared with 2023 because of the changes discussed below.
Ameren Missouri Ameren Illinois Natural Gas Other/Intersegment Eliminations Ameren Illinois Electric Distribution Ameren Transmission Ameren Other operations and maintenance expenses increased $5 million in 2025, compared with 2024 because of the changes discussed below.
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. Ameren Other income, net, increased $69 million in 2024, compared with 2023.
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. Ameren Other income, net, decreased $70 million in 2025, compared with 2024.
Ameren Illinois’ estimated capital expenditures are primarily for electric and natural gas transmission and distribution-related investments. 61 Table of Contents In February 2025, 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 2025.
Ameren Illinois’ estimated capital expenditures are primarily for electric and natural gas transmission and distribution-related investments. 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.
In both years, capital expenditures were made principally to maintain, upgrade, and improve the reliability of the transmission and distribution systems of Ameren Missouri and Ameren Illinois by investing in substation upgrades, energy center projects, and smart-grid technology. Additionally, the Ameren Companies invested in various software projects.
In both years, capital expenditures were made principally to maintain, upgrade, and improve the reliability of the transmission and distribution systems of Ameren Missouri and Ameren Illinois by investing in substation upgrades, energy center projects, and smart-grid technology.
During 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.
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.
Such environmental laws regulate air emissions; protect water bodies; manage the handling and disposal of hazardous substances and waste materials; siting and land use requirements; and potential ecological impacts.
Such environmental laws regulate air emissions; protect water bodies; regulate the handling and disposal of hazardous substances and waste materials; establish siting and land use requirements; and protect against ecological impacts.
Income Taxes The following table presents effective income tax rates for the years ended December 31, 2024 and 2023: 2024 2023 Ameren 7% 14% Ameren Missouri (18)% (2)% Ameren Illinois 24% 26% Ameren Illinois Electric Distribution 18% 24% Ameren Illinois Natural Gas 27% 27% Ameren Illinois Transmission 27% 26% Ameren Transmission 27% 26% See Note 12 – Income Taxes under Part II, Item 8, of this report for information regarding reconciliations of effective income tax rates for Ameren, Ameren Missouri, and Ameren Illinois.
Income Taxes The following table presents effective income tax rates for the years ended December 31, 2025 and 2024: 2025 2024 Ameren 9% 7% Ameren Missouri 5% (18)% Ameren Illinois 17% 24% Ameren Illinois Electric Distribution 14% 18% Ameren Illinois Natural Gas 19% 27% Ameren Illinois Transmission 19% 27% Ameren Transmission 14% 27% 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.
Dividends Ameren paid to its shareholders common stock dividends totaling $714 million, or $2.68 per share, in 2024 and $662 million, or $2.52 per share, in 2023. The amount and timing of dividends payable on Ameren’s common stock are within the sole discretion of Ameren’s board of directors.
Dividends Ameren paid to its shareholders common stock dividends totaling $768 million, or $2.84 per share, in 2025 and $714 million, or $2.68 per share, in 2024. The amount and timing of dividends payable on Ameren’s common stock are within the sole discretion of Ameren’s board of directors.
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. The Ameren Companies continually evaluate the adequacy and appropriateness of their liquidity arrangements for changing business conditions.
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.
A final ICC staff report is expected in early 2026 and will be used by the ICC to guide further action, if any. 69 Table of Contents • 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. 69 Table of Contents • Ameren Missouri’s next refueling and maintenance outage at the Callaway Energy Center is scheduled for the fall of 2026.
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.
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.
The plan is designed to upgrade Ameren Missouri’s electric infrastructure and includes investments that will upgrade the grid and accommodate more renewable energy. Investments under the plan are expected to total approximately $16.2 billion over the five-year period from 2025 through 2029, with expenditures largely recoverable under the PISA.
The plan is designed to upgrade Ameren Missouri’s electric infrastructure and includes investments that will upgrade the grid and accommodate more renewable energy. Investments under the plan are expected to total approximately $20.8 billion over the five-year period from 2026 through 2030, with expenditures largely recoverable under the PISA.
Ameren’s 2024 capital expenditures consisted of expenditures made by its subsidiaries, including $134 million by ATXI and other electric transmission subsidiaries. Ameren’s 2023 capital expenditures consisted of expenditures made by its subsidiaries, including $124 million by ATXI and other electric transmission subsidiaries.
Ameren’s 2025 capital expenditures consisted of expenditures made by its subsidiaries, including $154 million by ATXI and other electric transmission subsidiaries. Ameren’s 2024 capital expenditures consisted of expenditures made by its subsidiaries, including $134 million by ATXI and other electric transmission subsidiaries.
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.
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. Operations • The PPRA became effective in August 2025.
Changes in natural gas purchased for resale expenses are fully offset by changes in natural gas revenues under the PGA. 50 Table of Contents Other Operations and Maintenance Expenses Total by Segment (a) Increase (Decrease) by Segment Overall Ameren Increase of $103 Million (a) Includes $70 million and $60 million at Ameren Transmission in 2024 and 2023, respectively, and other/intersegment eliminations of $0 million and $34 million in 2024 and 2023, respectively.
Changes in natural gas purchased for resale expenses are fully offset by changes in natural gas revenues under the PGA. 50 Table of Contents Other Operations and Maintenance Expenses Total by Segment (a) Increase (Decrease) by Segment Overall Ameren Increase of $5 Million (a) Includes $74 million and $70 million at Ameren Transmission in 2025 and 2024, respectively, and other/intersegment eliminations of $(18) million and $– million in 2025 and 2024, respectively.
In addition, Ameren utilized aggregate cash proceeds of $346 million from the issuance of common stock under the ATM program, the DRPlus, and the 401(k) plan, and cash provided by operating activities to fund, in part, capital expenditures.
In addition, Ameren 61 Table of Contents 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.
For further information on the matters discussed above, see Note 2 – Rate and Regulatory Matters under Part II, Item 8, of this report, and the Outlook section below. 39 Table of Contents Earnings Net income attributable to Ameren common shareholders was $1,182 million, or $4.42 per diluted share, for 2024, and $1,152 million, or $4.38 per diluted share, for 2023.
For further information on the matters discussed above, see Note 2 – Rate and Regulatory Matters under Part II, Item 8, of this report, and the Outlook section below. Earnings Net income attributable to Ameren common shareholders was $1,456 million, or $5.35 per diluted share, for 2025, and $1,182 million, or $4.42 per diluted share, for 2024.
The following table reflects the gain and other comprehensive income, which would be offset by the removal of regulatory assets and liabilities and an increase in accumulated other comprehensive income, that would have resulted if accounting guidance for rate-regulated businesses had been eliminated as of December 31, 2024: Ameren Ameren Missouri Ameren Illinois Gains $ 2,896 $ 1,579 $ 1,204 Other comprehensive income (before taxes) - pension and other postretirement benefit plan activity 358 202 156 Accounting Estimate Uncertainties Affecting Application Benefit Plan Accounting Based on actuarial calculations, we accrue postretirement costs of providing future employee benefits for the benefit plans we offer our employees.
The following table reflects the gain and other comprehensive income, which would be offset by the removal of regulatory assets and liabilities and an increase in accumulated other comprehensive income, that would have resulted if accounting guidance for rate-regulated businesses had been eliminated as of December 31, 2025: Ameren Ameren Missouri Ameren Illinois Gains $ 3,035 $ 1,486 $ 1,422 Other comprehensive income (before taxes) - pension and other postretirement benefit plan activity 467 230 237 Accounting Estimate Uncertainties Affecting Application Benefit Plan Accounting Based on actuarial calculations, we accrue postretirement costs of providing future employee benefits for the benefit plans we offer our employees.
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; • 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 1,500 MWs of nuclear generation by 2040; • retiring all of Ameren Missouri’s coal-fired energy centers by 2042; • retiring 1,800 MWs of Ameren Missouri’s natural gas-fired energy centers by 2040 to comply with Illinois law; • the continued implementation of customer energy-efficiency and demand response programs; and • the expectation that Ameren Missouri will seek and receive NRC approval for an extension of the operating license for the Callaway Energy Center beyond its current 2044 expiration date.
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 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; • retiring all of Ameren Missouri’s coal-fired energy centers by 2042; • retiring 1,800 MWs of Ameren Missouri’s natural gas-fired energy centers by 2040 to comply with Illinois law; • the continued implementation of customer energy-efficiency and demand response programs; and 70 Table of Contents • the expectation that Ameren Missouri will seek and receive NRC approval for an extension of the operating license for the Callaway Energy Center beyond its current 2044 expiration date.
Ameren Illinois Other operations and maintenance expenses increased $88 million at Ameren Illinois in 2024, compared with 2023, as discussed below.
Ameren Illinois Other operations and maintenance expenses increased $39 million at Ameren Illinois in 2025, compared with 2024, as discussed below.
These revenue requirements represent increases in Ameren Illinois’ and ATXI’s revenue requirements of $94 million and $9 million, respectively, from the revenue requirements reflected in 2024 rates, primarily due to higher expected rate base.
These revenue requirements represent increases in Ameren Illinois’ and ATXI’s revenue requirements of $42 million and $33 million, respectively, from the revenue requirements reflected in 2025 rates, primarily due to higher expected rate base.
The following table presents the range of projected spending by segment: Range (in billions) Ameren Missouri (a) $ 16.0 – $ 17.5 Ameren Illinois Electric Distribution 3.1 – 3.3 Ameren Illinois Natural Gas 1.7 – 1.8 Ameren Transmission (b) 4.4 – 4.8 Ameren (a)(b) $ 25.2 – $ 27.4 (a) Amounts include investments under Ameren Missouri’s Smart Energy Plan.
The following table presents the range of projected spending by segment: Range (in billions) Ameren Missouri (a) $ 20.4 – $ 22.2 Ameren Illinois Electric Distribution 3.5 – 3.7 Ameren Illinois Natural Gas 1.8 – 1.9 Ameren Transmission (b) 4.8 – 5.3 Ameren (a)(b) $ 30.5 – $ 33.1 (a) Amounts include investments under Ameren Missouri’s Smart Energy Plan.

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Item 7A. Quantitative and Qualitative Disclosures About Market Risk

Market Risk — interest-rate, FX, commodity exposure

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Biggest changeInterest rate levels also influence the ROE allowed by our regulators in our other ratemaking jurisdictions, as well as the carrying costs associated with certain regulatory assets and liabilities. Credit Risk Credit risk represents the loss that would be recognized if counterparties should fail to perform as contracted.
Biggest changeTherefore, Ameren Illinois’ annual ROE for its electric energy-efficiency investments is directly correlated to the yields on such bonds, which are outside of Ameren Illinois’ control. Interest rate levels also influence the ROE allowed by our regulators in our other ratemaking jurisdictions, as well as the carrying costs associated with certain regulatory assets and liabilities.
We manage our interest rate exposure by controlling the amount of debt instruments within our total capitalization portfolio, by monitoring the effects of market changes on interest rates, and by entering into interest rate swaps to hedge a portion of our interest rate risk on cash flows related to forecasted debt issuances.
We manage our interest rate exposure by controlling the amount of debt instruments within our total capitalization portfolio, by monitoring the effects of market changes on interest rates, and by entering into interest rate swaps to hedge a portion of our interest rate risk on cash flows related to certain forecasted debt issuances.
Contributions to the plans and future costs could increase materially if we do not achieve pension and postretirement asset portfolio investment returns equal to or in excess of our 2025 assumed return on plan assets of 6.75%. Ameren Missouri also maintains a trust fund, as required by the NRC and Missouri law, to fund certain costs of nuclear plant decommissioning.
Contributions to the plans and future costs could increase materially if we do not achieve pension and postretirement asset portfolio investment returns equal to or in excess of our 2026 assumed return on plan assets of 6.75%. Ameren Missouri also maintains a trust fund, as required by the NRC and Missouri law, to fund certain costs of nuclear plant decommissioning.
This continues each successive year through March 2029. (c) Represents the percentage of purchased power price-hedged for fixed-price residential and nonresidential customers with less than 150 kilowatts of demand. Our exposure to commodity price risk for construction and maintenance activities is related to changes in market prices for metal commodities and to labor availability.
This continues each successive year through March 2030. (c) Represents the percentage of purchased power price-hedged for fixed-price residential and nonresidential customers with less than 150 kilowatts of demand. Our exposure to commodity price risk for construction and maintenance activities is related to changes in market prices for metal commodities and to labor availability.
While Ameren Missouri has minimum purchase obligations associated with these agreements, the majority of these agreements are not associated with any specific coal-fired energy center. (b) Represents the percentage of natural gas price-hedged for peak winter season of November through March. The year 2025 represents January 2025 through March 2025. The year 2026 represents November 2025 through March 2026.
While Ameren Missouri has minimum purchase obligations associated with these agreements, the majority of these agreements are not associated with any specific coal-fired energy center. (b) Represents the percentage of natural gas price-hedged for peak winter season of November through March. The year 2026 represents January 2026 through March 2026. The year 2027 represents November 2026 through March 2027.
Ameren Illinois has also entered into ICC-approved contracts for zero emission credits through May 2027 and for renewable energy credits with various terms, including contracts with 20-year terms ending 2032, and contracts entered into beginning in 2018 through 2024 with 15- to 20-year terms.
Ameren Illinois has also entered into ICC-approved contracts for zero emission credits through May 2027 and for renewable energy credits with various terms, including contracts with 20-year terms ending 2032, and contracts entered into beginning in 2018 through 2025 with 15- to 20-year terms.
The estimated increase in our annual interest expense and decrease in net income if interest rates were to increase by 100 basis points on variable-rate debt outstanding at December 31, 2024 is immaterial.
The estimated increase in our annual interest expense and decrease in net income if interest rates were to increase by 100 basis points on variable-rate debt outstanding at December 31, 2025 is immaterial.
The following table presents, as of December 31, 2024, the percentages of the projected required supply of coal and coal transportation for Ameren Missouri’s coal-fired energy centers, nuclear fuel for Ameren Missouri’s Callaway Energy Center, natural gas for Ameren Missouri’s and Ameren Illinois’ retail distribution, and purchased power for Ameren Illinois that are price-hedged over the period 2025 through 2029.
The following table presents, as of December 31, 2025, the percentages of the projected required supply of coal and coal transportation for Ameren Missouri’s coal-fired energy centers, nuclear fuel for Ameren Missouri’s Callaway Energy Center, natural gas for Ameren Missouri’s and Ameren Illinois’ retail distribution, and purchased power for Ameren Illinois that are price-hedged over the period 2026 through 2030.
If Ameren Missouri were to experience a temporary disruption of low-sulfur coal deliveries that caused it to exhaust its existing inventory, and if other sources of low-sulfur coal were not available, Ameren Missouri would have to use its existing emission allowances, purchase emission allowances, and reduce generation to achieve compliance with environmental regulations.
The suppliers of low-sulfur coal are limited. If Ameren Missouri were to experience a temporary disruption of low-sulfur coal deliveries that caused it to exhaust its existing inventory, and if other sources of low-sulfur coal were not available, Ameren Missouri would have to use its existing emission allowances, purchase emission allowances, and reduce generation to achieve compliance with environmental regulations.
In 2024, Ameren Illinois procured power on behalf of its customers for 25% of its total kilowatthour sales. Ameren Illinois purchases energy and capacity through bilateral contracts resulting from IPA procurement events, with any remaining needs procured through the MISO marketplace.
In 2025, Ameren Illinois procured power on behalf of its customers for 28% of its total kilowatthour sales. Ameren Illinois purchases energy and capacity through bilateral contracts resulting from IPA procurement events, with any remaining needs procured through the MISO marketplace.
Ameren Missouri’s exposure to equity price market risk is in large part mitigated because Ameren Missouri is currently allowed to recover its decommissioning costs, which would include unfavorable investment results, through electric rates. Additionally, Ameren and Ameren Illinois have COLI contracts with net cash surrender values of $150 million and $8 million, respectively, as of December 31, 2024.
Ameren Missouri’s exposure to equity price market risk is in large part mitigated because Ameren Missouri is currently allowed to recover its decommissioning costs, which would include unfavorable investment results, through electric rates. Additionally, Ameren and Ameren Illinois have COLI contracts with net cash surrender values of $102 million and $9 million, respectively, as of December 31, 2025.
As of December 31, 2024, this fund was invested in domestic equity securities (68%) and debt securities (31%). By maintaining a portfolio that includes long-term equity investments, Ameren Missouri seeks to maximize the returns to be used to fund nuclear decommissioning costs within acceptable parameters of risk.
As of December 31, 2025, this fund was invested in domestic equity securities (67%) and debt securities (32%). By maintaining a portfolio that includes long-term equity investments, Ameren Missouri seeks to maximize the returns to be used to fund nuclear decommissioning costs within acceptable parameters of risk.
When that option is selected, Ameren Illinois produces consolidated bills for the applicable retail customers to reflect charges for electric distribution and purchased receivables from the alternative retail electric suppler. As of December 31, 2024, Ameren Illinois’ balance of purchased accounts receivable associated with the utility consolidated billing and purchase of receivables services was $43 million.
When that option is selected, Ameren Illinois produces consolidated bills for the applicable retail customers to reflect charges for electric distribution and purchased receivables from the alternative retail electric supplier. As of December 31, 2025, Ameren Illinois’ balance of purchased accounts receivable associated with the utility consolidated billing and purchase of receivables services was $47 million.
The net cash surrender value of Ameren’s COLI is affected by the investment performance of a separate account in which Ameren holds a beneficial interest. As of December 31, 2024, that separate account is comprised of approximately 50% equity securities and 50% debt securities.
The net cash surrender value of Ameren’s COLI is affected by the investment performance of a separate account in which Ameren holds a beneficial interest. As of December 31, 2025, that separate account is comprised of approximately 40% equity securities and 60% debt securities.
These cost recovery mechanisms allow Ameren Missouri and Ameren Illinois to pass on to retail customers prudently incurred costs for fuel, purchased power, and natural gas supply. Ameren Missouri’s and Ameren Illinois’ strategy is designed to reduce the effect of market fluctuations for their customers. The effects of price volatility cannot be eliminated.
These cost recovery mechanisms allow Ameren Missouri and Ameren Illinois to pass on to retail customers prudently incurred costs for fuel, purchased power, and natural gas supply. Ameren Missouri’s and Ameren Illinois’ strategy is designed to reduce the effect of market fluctuations for their customers.
Through the IPA's 78 Table of Contents development and filing of the 2025 Electricity Procurement Plan, the ICC has approved the plan's proposal for multiple IPA procurement events over the following year. These events will procure portions of Ameren Illinois' energy and capacity forecasted requirements for forward delivery years through May 2028.
Through the IPA's development and filing of the 2026 Electricity Procurement Plan, the ICC has approved the plan's proposal for multiple IPA procurement events over the following year. These events will procure portions of Ameren Illinois' energy and capacity forecasted requirements for forward delivery years through May 2029.
The projected required supply of these commodities could be significantly affected by changes in our assumptions about customer demand for electricity and natural gas supplied by us and inventory levels, as well as Ameren Missouri’s generation output, among other matters. 2025 2026 2027 – 2029 Ameren: Coal (a) 93 % 73 % 47 % Coal transportation (a) 99 99 96 Nuclear fuel 100 100 100 Natural gas for distribution (b) 100 50 26 Purchased power for Ameren Illinois (c) 77 36 12 Ameren Missouri: Coal (a) 93 % 73 % 47 % Coal transportation (a) 99 99 96 Nuclear fuel 100 100 100 Natural gas for distribution (b) 91 52 25 Ameren Illinois: Natural gas for distribution (b) 100 % 49 % 27 % Purchased power (c) 77 36 12 (a) Ameren Missouri has agreements in place to purchase and transport coal to its energy centers.
The projected required supply of these commodities could be significantly affected by changes in our assumptions about customer demand for electricity and natural gas supplied by us and inventory levels, as well as Ameren Missouri’s generation output, among other matters. 2026 2027 2028 – 2030 Ameren: Coal (a) 98 % 76 % 49 % Coal transportation (a) 100 96 96 Nuclear fuel 100 100 100 Natural gas for distribution (b) 92 49 28 Purchased power for Ameren Illinois (c) 77 36 12 Ameren Missouri: Coal (a) 98 % 76 % 49 % Coal transportation (a) 100 96 96 Nuclear fuel 100 100 100 Natural gas for distribution (b) 75 46 22 Ameren Illinois: Natural gas for distribution (b) 96 % 49 % 29 % Purchased power (c) 77 36 12 (a) Ameren Missouri has agreements in place to purchase and transport coal to its energy centers.
Ameren Illinois has purchased approximately 14% of its summer 2025, 9% of its fall 2025, none of its winter 2025/26 and 2% of its spring 2026 capacity needs bilaterally, however, this percentage beyond May 2026 will be dependent on the results of future IPA procurement events. Daily energy balancing is also handled through the MISO marketplace.
Ameren Illinois has purchased approximately 55% of its summer 2026, 46% of its fall 2026, 40% of 78 Table of Contents its winter 2026/27 and 61% of its spring 2027 capacity needs bilaterally, however, this percentage beyond May 2027 will be dependent on the results of future IPA procurement events. Daily energy balancing is also handled through the MISO marketplace.
The allowed ROE under Ameren Illinois’ electric energy-efficiency investments formula ratemaking recovery mechanisms is based on the annual average of the monthly yields of the 30-year United States Treasury bonds plus 580 basis points. Therefore, Ameren Illinois’ annual ROE for its electric energy-efficiency investments is directly correlated to the yields on such bonds, which are outside of Ameren Illinois’ control.
Through 2026, the allowed ROE under Ameren Illinois’ electric energy-efficiency investments formula ratemaking recovery mechanisms is based on the annual average of the monthly yields of the 30-year United States Treasury bonds plus 580 basis points.
Additionally, Ameren Illinois faces risks associated with the purchase of receivables. The Illinois Public Utilities Act requires Ameren Illinois to establish electric utility consolidated billing and purchase of receivables services.
At December 31, 2025, no nonaffiliated customer represented more than 10% of our accounts receivable. Additionally, Ameren Illinois faces risks associated with the purchase of receivables. The Illinois Public Utilities Act requires Ameren Illinois to establish electric utility consolidated billing and purchase of receivables services.
Disruptions to the deliveries of low-sulfur coal from a supplier could compromise Ameren Missouri’s ability to operate in compliance with emission standards. The suppliers of low-sulfur coal are limited.
Commodity Supplier Risk The use of low-sulfur coal is part of Ameren Missouri’s environmental compliance strategy. Ameren Missouri has agreements with multiple suppliers to purchase low-sulfur coal through 2030 to comply with environmental regulations. Disruptions to the deliveries of low-sulfur coal from a supplier could compromise Ameren Missouri’s ability to operate in compliance with emission standards.
Exchange-traded contracts are supported by the financial and credit quality of the clearing members of the respective exchanges and carry only a nominal credit risk. In all other transactions, we are exposed to credit risk in the event of nonperformance by the counterparties to the transaction.
Credit Risk Credit risk represents the loss that would be recognized if counterparties should fail to perform as contracted. Exchange-traded contracts are supported by the financial and credit quality of the clearing members of the respective exchanges and carry only a nominal credit risk.
Our physical and financial instruments subject to credit risk primarily consist of trade accounts receivables and executory contracts with market risk exposures. Credit risk associated with trade receivables is mitigated by our diversified customer base. At December 31, 2024, no nonaffiliated customer represented more than 10% of our accounts receivable.
Our revenues are primarily derived from sales or delivery of electricity and natural gas to customers in Missouri and Illinois. Our physical and financial instruments subject to credit risk primarily consist of trade accounts receivables and executory contracts with market risk exposures. Credit risk associated with trade receivables is mitigated by our diversified customer base.
See Note 7 – Derivative Financial Instruments under Part II, Item 8, of this report for information on the potential loss on counterparty exposure as of December 31, 2024. Our revenues are primarily derived from sales or delivery of electricity and natural gas to customers in Missouri and Illinois.
In all other transactions, we are exposed to credit risk in the event of nonperformance by the counterparties to the transaction. See Note 7 – Derivative Financial Instruments under Part II, Item 8, of this report for information on the potential loss on counterparty exposure as of December 31, 2025.
Removed
Also see Note 14 – Commitments and Contingencies under Part II, Item 8, of this report for additional information. Commodity Supplier Risk The use of low-sulfur coal is part of Ameren Missouri’s environmental compliance strategy. Ameren Missouri has agreements with multiple suppliers to purchase low-sulfur coal through 2029 to comply with environmental regulations.
Added
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. This projected growth could create volatility for the prices of purchased power and capacity. The effects of price volatility cannot be eliminated.
Added
Pursuant to Illinois law, Ameren Illinois is required to enter into these contracts to comply with Illinois’ renewable energy and zero emission standards. These contracts, with the exception of certain contracts entered into in 2010, do not serve to meet Ameren Illinois’ energy and capacity needs.

Other AEE 10-K year-over-year comparisons