What changed in this filing

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Item 8. Financial Statements and Supplementary Data

2025-02-18 compared with 2024-02-29 · 689 added, 689 removed, 2387 unchanged (37% of the section changed)

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Opinions on the Financial Statements and Internal Control over Financial Reporting

We have audited the accompanying consolidated balance sheet of Ameren Corporation and its subsidiaries (the “Company”) as of December 31, 2023 and 2022, and the related consolidated statements of income and comprehensive income, of shareholders’ equity and of cash flows for each of the three years in the period ended December 31, 2023, including the related notes and financial statement schedules listed in the index appearing under Item 15(a)(2) (collectively referred to as the “consolidated financial statements”).

We have audited the accompanying consolidated balance sheet of Ameren Corporation and its subsidiaries (the “Company”) as of December 31, 2024 and 2023, and the related consolidated statement of income and comprehensive income, of shareholders’ equity and of cash flows for each of the three years in the period ended December 31, 2024, including the related notes and financial statement schedules listed in the index appearing under Item 15(a)(2) (collectively referred to as the “consolidated financial statements”).

We also have audited the Company’s internal control over financial reporting as of December 31, 2024, based on criteria established in Internal Control - Integrated Framework (2013) issued by the Committee of Sponsoring Organizations of the Treadway Commission (COSO).

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Also, projections of any evaluation of effectiveness to future periods are subject to the risk that controls may become inadequate because of changes in conditions, or that the degree of compliance with the policies or procedures may deteriorate.

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Critical Audit Matters

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We have not been able to determine the specific year we began serving as auditor of the Company.

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Report of Independent Registered Public Accounting Firm

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Opinion on the Financial Statements

We have audited the accompanying consolidated balance sheet of Union Electric Company and its subsidiaries (the “Company”) as of December 31, 2023 and 2022, and the related consolidated statements of income, of shareholders’ equity and of cash flows for each of the three years in the period ended December 31, 2023, including the related notes and financial statement schedule listed in the index appearing under Item 15(a)(2) (collectively referred to as the “consolidated financial statements”).

We have audited the accompanying consolidated balance sheet of Union Electric Company and its subsidiaries (the “Company”) as of December 31, 2024 and 2023, and the related consolidated statement of income, of shareholders’ equity and of cash flows for each of the three years in the period ended December 31, 2024, including the related notes and financial statement schedule listed in the index appearing under Item 15(a)(2) (collectively referred to as the “consolidated financial statements”).

In our opinion, the consolidated financial statements present fairly, in all material respects, the financial position of the Company as of December 31, 2024 and 2023, and the results of its operations and its cash flows for each of the three years in the period ended December 31, 2024 in conformity with accounting principles generally accepted in the United States of America.

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We conducted our audits of these consolidated financial statements in accordance with the standards of the PCAOB.

Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the consolidated financial statements are free of material misstatement, whether due to error or fraud.

Those standards require that we plan and perform the audits to obtain reasonable assurance about whether the consolidated financial statements are free of material misstatement, whether due to error or fraud.

The Company is not required to have, nor were we engaged to perform, an audit of its internal control over financial reporting.

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Management must use judgment to conclude that costs deferred as regulatory assets are probable of future recovery.

Additionally, management recognizes revenue for alternative revenue programs that allow for an automatic rate adjustment, are probable of recovery, and are collected within 24 months of the end of the annual period in which they are recognized.

Management’s conclusions are based on certain factors including, but not limited to, regulatory commission orders, legislation, or historical experience, as well as management’s discussions with legal counsel.

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impacted by updates in regulatory commission orders, legislation, historical experience, or management’s discussions with legal counsel, (ii) the probability of recovery of regulatory assets and refund of regulatory liabilities recorded before approval has been received from the regulator, and (iii) regulatory mechanisms meeting the alternative revenue program criteria, which in turn led to a high degree of auditor judgment, subjectivity, and effort when performing audit procedures and evaluating audit evidence obtained related to management’s application of regulatory accounting, assessment of probability of recovery of regulatory assets and refund of regulatory liabilities, and expected timing of collection within 24 months of the end of the annual period in which mechanisms are recognized.

(ii) the probability of recovery of regulatory assets and refund of regulatory liabilities recorded before approval has been received from the regulator.

Addressing the matter involved performing procedures and evaluating audit evidence in connection with forming our overall opinion on the consolidated financial statements.

These procedures included testing the effectiveness of controls relating to management’s implementation and application of new or existing regulatory assets or liabilities, including controls related to evaluating the probability of recovery of regulatory assets and refund of regulatory liabilities, and alternative revenue programs.

These procedures also included, among others, (i) testing calculations of new and existing regulatory assets or liabilities by comparison to provisions and formulas outlined in regulatory commission orders or legislation, (ii) evaluating management’s assessment of the probability of recovery of regulatory assets and refund of regulatory liabilities, and (iii) evaluating management’s assessment of regulatory mechanisms meeting the alternative revenue program criteria and the expected timing of collection within 24 months of the end of the annual period in which mechanisms are recognized.

/s/ PricewaterhouseCoopers LLP

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We have not been able to determine the specific year we began serving as auditor of the Company.

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Report of Independent Registered Public Accounting Firm

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Opinion on the Financial Statements

We have audited the accompanying balance sheet of Ameren Illinois Company (the “Company”) as of December 31, 2023 and 2022, and the related statements of income, of shareholders’ equity and of cash flows for each of the three years in the period ended December 31, 2023, including the related notes and financial statement schedule listed in the index appearing under Item 15(a)(2) (collectively referred to as the “financial statements”).

We have audited the accompanying balance sheet of Ameren Illinois Company (the “Company”) as of December 31, 2024 and 2023, and the related statement of income, of shareholders’ equity and of cash flows for each of the three years in the period ended December 31, 2024, including the related notes and financial statement schedule listed in the index appearing under Item 15(a)(2) (collectively referred to as the “financial statements”).

In our opinion, the financial statements present fairly, in all material respects, the financial position of the Company as of December 31, 2024 and 2023, and the results of its operations and its cash flows for each of the three years in the period ended December 31, 2024 in conformity with accounting principles generally accepted in the United States of America.

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We conducted our audits of these financial statements in accordance with the standards of the PCAOB.

Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements are free of material misstatement, whether due to error or fraud.

Those standards require that we plan and perform the audits to obtain reasonable assurance about whether the financial statements are free of material misstatement, whether due to error or fraud.

The Company is not required to have, nor were we engaged to perform, an audit of its internal control over financial reporting.

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The principal considerations for our determination that performing procedures relating to accounting for the effects of regulation is a critical audit matter are the significant judgment by management when accounting for (i) new or existing regulatory assets or liabilities that were impacted by updates in regulatory commission orders, legislation, historical experience, or management’s discussions with legal counsel, (ii) the probability of recovery of regulatory assets and refund of regulatory liabilities recorded before approval has been received from the regulator, and (iii) regulatory mechanisms meeting the alternative revenue program criteria, which in turn led to a high degree of auditor

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judgment, subjectivity, and effort when performing audit procedures and evaluating audit evidence obtained related to management’s application of regulatory accounting, assessment of probability of recovery of regulatory assets and refund of regulatory liabilities, and expected timing of collection within 24 months of the end of the annual period in which mechanisms are recognized.

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We have served as the Company’s auditor since 1998.

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AMEREN CORPORATION

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Operating Expenses:

Fuel 514 473 581

Purchased power 1,298 1,547 606

Fuel and purchased power 1,681 1,812 2,020

Natural gas purchased for resale 320 355 657

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( 3 ) ( 5 ) ( 14 )

Unrealized net gain on derivative hedging instruments, net of income taxes of $ — , $ — , and $ — , respectively

Comprehensive Income 1,187 1,152 1,065

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

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AMEREN CORPORATION

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Current regulatory assets 366 365

Investments in industrial development revenue bonds — 240

Current collateral assets 14 142

Other current assets 162 139

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Goodwill 411 411

Regulatory assets 1,810 1,426

Regulatory assets (includes $ 465 and $— at 2024 and 2023 related to VIEs, respectively)

Pension and other postretirement benefits 757 581

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Current Liabilities:

Current maturities of long-term debt $ 849 $ 340

Current maturities of long-term debt (includes $ 17 and $— at 2024 and 2023 related to VIEs, respectively)

Short-term debt 1,143 536

Accounts and wages payable 1,059 1,136

Interest accrued 196 147

Customer deposits 223 176

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Total current liabilities 3,413 3,345

Long-term Debt, Net 15,121 13,685

Long-term Debt, Net (includes $ 448 and $— at 2024 and 2023 related to VIEs, respectively)

17,262 15,121

Deferred Credits and Other Liabilities:

Accumulated deferred income taxes and investment tax credits, net 4,176 3,804

Accumulated deferred income taxes and production and investment tax credits, net 4,474 4,176

Regulatory liabilities 5,897 5,512

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

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AMEREN CORPORATION

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Amortization of debt issuance costs and premium/discounts 19 16 21

Deferred income taxes and investment tax credits, net 229 170 156

Deferred income taxes and production and investment tax credits, net 127 229 170

Allowance for equity funds used during construction ( 76 ) ( 54 ) ( 43 )

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Short-term debt, net 607 ( 533 ) 522

Maturities of long-term debt ( 100 ) ( 505 ) ( 8 )

Maturities and extinguishment of long-term debt ( 893 ) ( 100 ) ( 505 )

Issuances of long-term debt 2,535 2,295 1,467

Issuances of common stock 273 346 333

Redemptions of Ameren Illinois preferred stock — — ( 13 )

Employee payroll taxes related to stock-based compensation ( 8 ) ( 20 ) ( 16 )

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$ 611 $ 546 $ 476

Income taxes, net (includes production tax credit sale proceeds of $ 49 , $ — , and $ — , respectively)

Income taxes, net (includes production and investment tax credit sale proceeds of $ 95 , $ 49 , and $ — , respectively)

( 92 ) ( 24 ) ( 8 )

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

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AMEREN CORPORATION

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Beginning of year 7,216 6,860 6,502

Settlement of non-ATM program forward sale agreement through common shares issuance — — 113

Shares issued under the ATM program 233 299 292

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Accumulated Other Comprehensive Income (Loss):

Derivative financial instruments, beginning of year — — —

Change in derivative financial instruments 3 — —

Derivative financial instruments, end of year 3 — —

Deferred retirement benefit costs, beginning of year ( 6 ) ( 1 ) 13

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Deferred retirement benefit costs, end of year ( 9 ) ( 6 ) ( 1 )

Total accumulated other comprehensive gain (loss), end of year ( 6 ) ( 1 ) 13

Total accumulated other comprehensive loss, end of year ( 6 ) ( 6 ) ( 1 )

Total Shareholders’ Equity $ 12,114 $ 11,349 $ 10,508

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Dividends paid to noncontrolling interest holders ( 5 ) ( 5 ) ( 5 )

Redemptions of Ameren Illinois preferred stock — — ( 13 )

Noncontrolling interests, end of year 129 129 129

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Common stock shares outstanding at beginning of year 266.3 262.0 257.7

Shares issued under non-ATM program forward sale agreement — — 1.6

Shares issued under the ATM program 2.9 3.2 3.4

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

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UNION ELECTRIC COMPANY (d/b/a AMEREN MISSOURI)

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Operating Expenses:

Fuel 514 473 581

Purchased power 483 677 227

Fuel and purchased power 1,071 997 1,150

Natural gas purchased for resale 60 79 104

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The accompanying notes as they relate to Ameren Missouri are an integral part of these consolidated financial statements.

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UNION ELECTRIC COMPANY (d/b/a AMEREN MISSOURI)

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Cash and cash equivalents $ — $ —

Advances to money pool 43 —

Accounts receivable – trade (less allowance for doubtful accounts of $ 12 and $ 12 , respectively)

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Current regulatory assets 66 101

Investments in industrial development revenue bonds — 240

Current collateral assets 5 101

Other current assets 70 68

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Nuclear decommissioning trust fund 1,342 1,150

Regulatory assets 755 594

Regulatory assets (includes $ 465 and $ — at 2024 and 2023 related to VIEs, respectively)

Pension and other postretirement benefits 211 157

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Current Liabilities:

Current maturities of long-term debt $ 350 $ 240

Current maturities of long-term debt (includes $ 17 and $ — at 2024 and 2023 related to VIEs, respectively)

Short-term debt — 170

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Accounts payable – affiliates 50 53

Interest accrued 88 69

Other current liabilities 235 181

Total current liabilities 1,019 1,747

Long-term Debt, Net 5,991 5,846

Long-term Debt, Net (includes $ 448 and $ — at 2024 and 2023 related to VIEs, respectively)

Long-term Debt, Net – Related Parties 57 —

Deferred Credits and Other Liabilities:

Accumulated deferred income taxes and investment tax credits, net 2,122 1,982

Accumulated deferred income taxes and production and investment tax credits, net 2,217 2,122

Regulatory liabilities 3,176 2,959

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The accompanying notes as they relate to Ameren Missouri are an integral part of these consolidated financial statements.

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UNION ELECTRIC COMPANY (d/b/a AMEREN MISSOURI)

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Amortization of debt issuance costs and premium/discounts 7 7 7

Deferred income taxes and investment tax credits, net 28 21 3

Deferred income taxes and production and investment tax credits, net ( 29 ) 28 21

Allowance for equity funds used during construction ( 58 ) ( 30 ) ( 24 )

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$ 244 $ 225 $ 230

Income taxes, net (includes production tax credit sale proceeds of $ 49 , $ — , and $ — , respectively)

Income taxes, net (includes production and investment tax credit sale proceeds of $ 95 , $ 49 , and $ – , respectively)

( 136 ) ( 19 ) ( 20 )

The accompanying notes as they relate to Ameren Missouri are an integral part of these consolidated financial statements.

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UNION ELECTRIC COMPANY (d/b/a AMEREN MISSOURI)

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The accompanying notes as they relate to Ameren Missouri are an integral part of these consolidated financial statements.

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AMEREN ILLINOIS COMPANY (d/b/a AMEREN ILLINOIS)

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The accompanying notes as they relate to Ameren Illinois are an integral part of these financial statements.

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AMEREN ILLINOIS COMPANY (d/b/a AMEREN ILLINOIS)

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Inventories 244 225

Prepaid assets 59 49

Current regulatory assets 281 252

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Long-term Debt, Net 5,549 5,232

Long-term Debt, Net – Related Parties 3 —

Deferred Credits and Other Liabilities:

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The accompanying notes as they relate to Ameren Illinois are an integral part of these financial statements.

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AMEREN ILLINOIS COMPANY (d/b/a AMEREN ILLINOIS)

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Maturities of long-term debt — ( 100 ) ( 400 )

Redemption of preferred stock — — ( 13 )

Issuances of long-term debt 624 498 848

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Capital contribution from parent 36 91 15

Other — — ( 13 )

Net cash provided by financing activities 165 678 612

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The accompanying notes as they relate to Ameren Illinois are an integral part of these financial statements.

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AMEREN ILLINOIS COMPANY (d/b/a AMEREN ILLINOIS)

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Preferred Stock 49 49 49

Beginning of year 49 49 62

Redemptions of preferred stock — — ( 13 )

Preferred stock, end of year 49 49 49

Retained Earnings:

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The accompanying notes as they relate to Ameren Illinois are an integral part of these financial statements.

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AMEREN CORPORATION (Consolidated)

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All intercompany transactions have been eliminated.

Ameren Missouri’s subsidiaries were created for the ownership of renewable generation projects.

Ameren Illinois has no subsidiaries.

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See Note 2 – Rate and Regulatory Matters for additional information on our regulatory frameworks, regulatory recovery mechanisms, and regulatory assets and liabilities recorded at December 31, 2024 and 2023.

We continually assess the recoverability of our regulatory assets and probability of refund of our regulatory liabilities.

We periodically assess the recoverability of our regulatory assets and probability of refund of our regulatory liabilities.

Regulatory assets are charged to earnings when it is no longer probable that such amounts will be recovered through future revenues.

To the extent that refunds to customers related to regulatory liabilities are no longer probable, the amounts are credited to earnings.

To the extent that refunds to customers related to regulatory liabilities are eliminated by the regulator or are no longer probable, the amounts are credited to earnings.

Cash, Cash Equivalents, and Restricted Cash

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See Note 15 – Supplemental Information for a reconciliation of cash, cash equivalents, and restricted cash reported within the balance sheets and the statements of cash flows.

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Allowance for Doubtful Accounts Receivable

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Inventories are recorded at the lower of weighted-average cost or net realizable value.

Inventories are capitalized when purchased and then expensed as consumed or capitalized as property, plant, and equipment when installed, as appropriate using the weighted-average cost method.

Inventories are charged to expense or capitalized to property, plant and equipment when issued, as appropriate, using the weighted-average cost method.

See Note 15 – Supplemental Information for the components of inventories.

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See Asset Retirement Obligations and Removal Costs section below and Note 3 – Property, Plant, and Equipment, Net for additional information.

Ameren Missouri’s cost of nuclear fuel is capitalized as a part of “Property, Plant, and Equipment, Net” on Ameren and Ameren Missouri’s balance sheets and then amortized to “Operating Expenses – Fuel” in their respective statements of income on a unit-of-production basis.

Nuclear fuel amortization is reflected as a part of “Depreciation and amortization” on their respective statements of cash flow.

Ameren Missouri’s cost of nuclear fuel is capitalized as a part of “Property, Plant, and Equipment, Net” on Ameren and Ameren Missouri’s balance sheets and then amortized to “Operating Expenses – Fuel and purchased power” in their respective statements of income on a unit-of-production basis.

Nuclear fuel amortization is reflected as a part of “Amortization of nuclear fuel” on their respective statements of cash flow.

Plant to be Abandoned, Net

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The net book value will be classified as a regulatory asset on the balance sheet when the asset is no longer in service or as required by a rate order.

In relation to the NSR and Clean Air Act litigation discussed in Note 14 – Commitments and Contingencies, in December 2021, Ameren Missouri filed a motion with the United States District Court for the Eastern District of Missouri to modify a previously issued remedy order to allow the retirement of the Rush Island Energy Center in lieu of installing a flue gas desulfurization system, which was granted to establish an October 15, 2024 retirement date.

As of December 31, 2023 and 2022, Ameren and Ameren Missouri determined that the Rush Island Energy Center met the criteria to be considered probable of abandonment and have classified its remaining net book value as plant to be abandoned, net, within “Property, Plant, and Equipment, Net” on Ameren’s and Ameren Missouri’s balance sheets.

See Note 3 – Property, Plant, and Equipment, Net for our plant to be abandoned balance as of December 31, 2023 and 2022.

Ameren Missouri concluded no abandonment loss was required for the Rush Island Energy Center as of December 31, 2023.

As part of the assessment of any potential future abandonment loss, consideration will be given to rate and securitization orders issued by the MoPSC to Ameren Missouri and to orders issued to other Missouri utilities with similar facts.

See Note 2 – Rate and Regulatory Matters for Ameren Missouri’s November 2023 petition filed with the MoPSC seeking securitization of the Rush Island Energy Center.

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Depreciation is provided over the estimated lives of the various classes of depreciable property by applying composite rates on a straight-line basis to the cost basis of such property.

In relation to the NSR and Clean Air Act litigation discussed in Note 14 – Commitments and Contingencies, Ameren Missouri retired the Rush Island Energy Center on October 15, 2024.

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

In December 2024, AMF issued $ 476 million of securitized utility tariff bonds.

As a result of the financing order and the issuance of the securitized utility tariff bonds, Ameren Missouri concluded no abandonment loss was required for the Rush Island Energy Center and classified the remaining net book value as a regulatory asset as of December 31, 2024.

See Variable Interest Entities below, Note 2 – Rate and Regulatory Matters, and Note 5 – Long-term Debt and Equity Financings for additional information on Ameren Missouri's securitization of the Rush Island Energy Center's costs.

As of December 31, 2023, Ameren and Ameren Missouri determined that the Rush Island Energy Center met the criteria to be considered probable of abandonment and classified its remaining net book value as plant to be abandoned, net, within “Property, Plant, and Equipment, Net” on Ameren’s and Ameren Missouri’s balance sheets.

See Note 3 – Property, Plant, and Equipment, Net for our plant to be abandoned balance as of December 31, 2023.

Depreciation is provided over the estimated lives of the various classes of depreciable tangible property by applying composite rates on a straight-line basis to the cost basis of such property.

The composite rates include a provision for the estimated removal cost of property, plant, and equipment retired from service, net of salvage.

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Ameren and Ameren Illinois evaluate goodwill for impairment in each of their reporting units as of October 31 each year, or more frequently if events occur or circumstances change that would more likely than not reduce the fair value of their reporting units below their carrying amounts.

To determine whether the fair value of a reporting unit is more likely than not greater than its carrying amount, Ameren and Ameren Illinois elect to perform either a qualitative assessment or to bypass the qualitative assessment and perform a quantitative test.

To determine whether the fair value of a reporting unit is more likely than not greater than its carrying amount, Ameren and Ameren Illinois can elect to perform either a qualitative assessment or to bypass the qualitative assessment and perform a quantitative test.

Ameren and Ameren Illinois elected to perform a qualitative assessment for their annual goodwill impairment test conducted as of October 31, 2024.

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Variable Interest Entities

As of December 31, 2023 and 2022, Ameren had unconsolidated variable interests in various equity method investments, primarily to advance clean and resilient energy technologies, totaling $ 73 million and $ 68 million, respectively, included in “Other assets” on Ameren’s

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consolidated balance sheet.

Variable Interest Entities that are Consolidated

AMF was formed in 2024, for the purpose of issuing and servicing securitized utility tariff bonds related to costs for the accelerated retirement of the Rush Island Energy Center.

Ameren Missouri is the primary beneficiary of this entity because it has the power to direct the activities that most significantly impact the economic performance of the company, as well as the obligation to absorb losses or the right to receive benefits from the company.

The entity is considered a variable interest entity primarily because its equity capitalization is insufficient to support its operations.

The entity’s primary assets and liabilities are comprised of regulatory assets related to the unrecovered net plant balance associated with the facility, among other costs, and long-term debt.

Ameren and Ameren Missouri consolidate AMF, which Ameren Missouri wholly owns, and both manages and controls the entity’s operating activities.

For additional information on the securitization of the Rush Island Energy Center costs, see Note 2 – Rate and Regulatory Matters.

For additional information on the securitized tariff bond issuance, see Note 5 – Long-term Debt and Equity Financings.

The following table presents the carrying values of AMF’s assets and liabilities included on Ameren’s and Ameren Missouri’s consolidated balance sheets as of December 31, 2024:

Other current assets (a)

Noncurrent regulatory assets (a)

Current maturities of long term debt (b)

Interest accrued (b)

Long-term debt, net (b)

(a) Assets may be used only to meet AMF’s obligations and commitments.

(b) The securitized tariff bondholders have no recourse to Ameren Missouri.

Variable Interest Entities that are not Consolidated

As of December 31, 2024 and 2023, Ameren had unconsolidated variable interests in various equity method investments, primarily to advance clean and resilient energy technologies, totaling $ 74 million and $ 73 million, respectively, included in “Other assets” on Ameren’s consolidated balance sheet.

Any earnings or losses related to these investments are included in “Other Income, Net” on Ameren’s consolidated statement of income and comprehensive income.

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Ameren and Ameren Missouri have recorded AROs for retirement costs associated with decommissioning of Ameren Missouri’s Callaway and wind renewable energy centers, certain Ameren Missouri solar energy centers, CCR facilities, and river structures at certain energy centers used for unloading coal and circulating water systems.

Additionally, Ameren, Ameren Missouri, and Ameren Illinois have recorded AROs for retirement costs associated with asbestos removal and the disposal of certain transformers.

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 for a reconciliation of the beginning and ending carrying amounts of AROs.

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Retail distribution, electric transmission, and off-system revenues, including the underlying components described above, represent a series of goods or services that are substantially the same and have the same pattern of transfer over time to our customers.

Revenues from contracts with customers are equal to the amounts billed and our estimate of electric and natural gas retail distribution services provided but

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unbilled at the end of each accounting period.

Revenues from contracts with customers are equal to the amounts billed and our estimate of electric and natural gas retail distribution services provided but unbilled at the end of each accounting period.

Customers are billed at least monthly, and payments are due less than one month after goods and/or services are provided.

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For certain regulatory recovery mechanisms that are alternative revenue programs rather than revenues from contracts with customers, we recognize revenues that have been authorized for rate recovery, are objectively determinable and probable of recovery, and are expected to be collected from customers within two years from the end of the year.

Our alternative revenue programs include revenue requirement reconciliations, the MEEIA, the VBA, and the WNAR.

Our alternative revenue programs include revenue requirement reconciliations, the MEEIA, the RBA, the VBA, and the WNAR.

These revenues are subsequently recognized as revenues from contracts with customers when billed, with an offset to alternative revenue program revenues.

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Ameren Missouri records these purchase and sale transactions on a net hourly position.

Ameren Missouri records net purchases in a single hour in “Operating Expenses – Purchased power” and net sales in a single hour in “Operating Revenues – Electric” in its statement of income.

Ameren Illinois records net purchases in “Operating Expenses – Purchased power” in its statement of income to reflect all of its MISO transactions relating to the procurement of power for its customers.

On occasion, Ameren Missouri’s and Ameren Illinois’ prior-period transactions will be resettled outside the routine settlement process because of a change in the MISO’s tariff or a material interpretation thereof.

In these cases, Ameren Missouri and Ameren Illinois recognize revenues and expenses associated with resettlements once the resettlement is probable and the resettlement amount can be estimated.

There were no material MISO resettlements in 2023, 2022, or 2021.

Ameren Missouri records net purchases in a single hour in “Operating Expenses – Fuel and purchased power” and net sales in a single hour in “Operating Revenues – Electric” in its statement of income.

Ameren Illinois records net purchases in “Operating Expenses – Fuel and purchased power” in its statement of income to reflect all of its MISO transactions relating to the procurement of power for its customers.

Stock-based Compensation

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Ameren recognizes as compensation expense the estimated fair value of stock-based compensation on a straight-line basis over the requisite vesting period.

To the extent that actual forfeitures differ from estimated forfeitures, such differences are accounted for as an adjustment to compensation expense and recorded in the period that estimates are revised.

To the extent that actual forfeitures differ from estimated forfeitures, such differences are accounted for as an

adjustment to compensation expense and recorded in the period that estimates are revised.

Compensation cost is ultimately recognized only for awards for which the requisite service was provided.

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A regulatory asset has been established to recognize the probable recovery through future customer rates of tax benefits related to the equity component of allowance for funds used during construction, as well as the effects of tax rate increases.

To the extent deferred tax balances are included in rate base, the revaluation of deferred taxes is recorded as a regulatory asset or liability on the balance sheet and will be collected from, or refunded to, customers.

For deferred tax balances not included in rate base, the revaluation of deferred taxes is recorded as an adjustment to income tax expense on the income statement.

To the extent deferred tax balances are included in rate base, the revaluation of deferred taxes caused by a change in the statutory rate is recorded as a regulatory asset or liability on the balance sheet and will be collected from, or refunded to, customers.

For deferred tax balances not included in rate base, the revaluation of deferred taxes caused by a change in the statutory rate is recorded as an adjustment to income tax expense on the income statement.

Tax credits other than investment tax credits are recognized as a reduction to income tax expense when earned.

The benefits for investment tax credits not transferred under the IRA are amortized over the book depreciable lives of the related property.

For production and other tax credits otherwise eligible to be recognized when earned and for investment tax credits transferred under the IRA, Ameren considers the impact of rate regulation to determine if these credits and related adjustments should be deferred as regulatory liabilities.

See Note 2 – Rate and Regulatory Matters for additional information on Ameren Missouri’s production and investment tax credit tracker and the RESRAM.

Ameren Missouri, Ameren Illinois, and all the other Ameren subsidiary companies are parties to a tax allocation agreement with Ameren (parent) that provides for the allocation of consolidated tax liabilities.

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See Note 13 – Related-party Transactions for information regarding capital contributions under the tax allocation agreement.

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NOTE 2 – RATE AND REGULATORY MATTERS

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• Initial rates based on future test years

• Revenues decoupled from sales volumes

• Revenues decoupled from sales volumes and wholesale and miscellaneous revenues through the RBA

• Future test year ratemaking

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Regulatory mechanisms • PISA

• Rush Island Securitization

• Pension and postretirement benefit costs

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• Production and investment tax credits or proceeds from the sale of certain tax credits allowed under the IRA

• Electric distribution service and energy-efficiency revenue requirement reconciliation adjustments (b)

• Electric distribution service and energy-efficiency revenue requirement reconciliation adjustments (a)

• Power procurement

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• Zero emission credits

• Customer generation rebate program costs

• Certain environmental costs

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• Revenue requirement reconciliation adjustment

(a) Ameren Illinois used the IEIMA performance-based formula ratemaking framework to establish annual electric distribution customer rates effective through 2023.

In December 2023, the ICC approved an MYRP to establish rates effective 2024 through 2027.

See below for additional information regarding the MYRP approved in December 2023.

(b) Reconciliation adjustments under an MYRP are subject to a reconciliation cap which limits annual adjustment to 105 %.

(a) Reconciliation adjustments under an MYRP are subject to a reconciliation cap which limits annual adjustment to 105 %.

See below for additional information regarding the reconciliation cap.

Reconciliation hearings to determine the accuracy and prudence of natural gas capital investments recovered under the QIP from 2020 to 2023 are ongoing.

The MoPSC regulates rates and other matters for Ameren Missouri’s electric service and natural gas distribution businesses.

The rates Ameren Missouri charges customers for these services are established in a traditional regulatory rate review, which takes up to 11 months to complete, based on a historical test year and the revenue requirement established in the review.

Ameren Missouri has recovery mechanisms, including the RESRAM, FAC, MEEIA, PGA, and WNAR, that allow customer rates to be adjusted without a traditional regulatory rate review.

Ameren Missouri has recovery mechanisms, including the RESRAM, FAC, MEEIA, PGA, and WNAR, as well as a rider related to the securitization of the Rush Island Energy Center, that allow customer rates to be adjusted without a traditional regulatory rate review.

These riders, along with the PISA, each described in more detail below, partially mitigate the effects of regulatory lag.

Ameren Missouri also employs other recovery mechanisms, including a renewable energy standard cost tracker, as well as electric and natural gas trackers for uncertain income tax positions, certain excess deferred income taxes, property taxes, and pension and postretirement benefit costs.

Ameren Missouri also employs other recovery mechanisms, including a renewable energy standard cost tracker, as well as electric and natural gas trackers for certain excess deferred income taxes, property taxes, and pension and postretirement benefit costs.

Each of these trackers allows Ameren Missouri to defer the difference between actual costs incurred and costs included in customer rates as a regulatory asset or regulatory liability, with the difference expected to be reflected in base rates in a subsequent MoPSC rate order.

Ameren Missouri also employs a tracker for the utilization of production and investment tax credits or proceeds from the sale of such tax credits allowed under the IRA.

Production and investment tax credits produced by renewable energy centers that support compliance with the state of Missouri’s renewable energy standard, such as the High Prairie Renewable and Atchison Renewable energy centers, are not eligible for tracking under this mechanism as they are included in the RESRAM.

Production and investment tax credits produced by renewable energy centers that support compliance with the state of Missouri’s renewable energy standard, such as the High Prairie, Atchison, and Huck Finn energy centers, are not eligible for tracking under this mechanism as they are included in the RESRAM.

Ameren Missouri’s cost recovery under any of its recovery mechanisms is subject to MoPSC prudence reviews.

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The PISA permits Ameren Missouri to defer and recover 85 % of the depreciation expense for investments in qualifying property, plant, and equipment placed in service and not included in base rates.

Investments not eligible for recovery under the PISA include amounts related to new nuclear and natural gas generating units and service to new customer premises.

Additionally, the PISA permits Ameren Missouri to earn a return at the applicable WACC on rate base that incorporates those qualifying investments, as well as changes in total accumulated depreciation excluding retirements and plant-related deferred income taxes since the previous regulatory rate review.

Additionally, the PISA permits Ameren Missouri to earn a return at the applicable WACC on 85 % of rate base that incorporates those qualifying investments, as well as changes in total accumulated depreciation excluding retirements and plant-related deferred income taxes since the previous regulatory rate review.

The regulatory asset for accumulated PISA deferrals also earns a return at the applicable WACC until added to rate base prospectively.

Ameren Missouri recognizes an offset to “Interest Charges” on its consolidated statement of income for its carrying cost of debt relating to each return allowed under the PISA, with the difference between the applicable WACC and its carrying cost of debt recognized in revenues when recovery of PISA deferrals is reflected in customer rates.

Approved PISA deferrals are recovered over a period of 20 years following a regulatory rate review.

Approved PISA deferrals are recovered over a period of 20 years following a

regulatory rate review.

Additionally, under the RESRAM, Ameren Missouri is permitted to recover the 15 % of depreciation expense not recovered under the PISA, and earn a return at the applicable WACC for investments in renewable generation plant placed in service to comply with Missouri’s renewable energy standard.

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As a result of the PISA election, additional provisions of the law apply to Ameren Missouri, including limitations on electric customer rate increases.

The rate increase approved by the June 2023 MoPSC electric rate order discussed below did not exceed the rate increase limitation applicable through 2023.

Pursuant to a Missouri law that became effective in August 2022, 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 a Missouri law, Ameren Missouri’s PISA election was extended through December 2028 and an additional extension through December 2033 is allowed if requested by Ameren Missouri and approved by the MoPSC, among other things.

This law also established a 2.5 % annual limit on increases to the electric service revenue requirement used to set customer rates, compared to the revenue requirement established in the immediately preceding rate order, due to the inclusion of incremental PISA deferrals in the revenue requirement.

The limitation will be effective for revenue requirements approved by the MoPSC after January 1, 2024.

The RESRAM permits Ameren Missouri to recover or refund, through customer rates, the difference between the cost of compliance, net of federal production and investment tax credits, with Missouri’s renewable energy standard and the amount set in base rates.

Effective February 28, 2022, all sales from the High Prairie Renewable and Atchison Renewable energy centers are included in the RESRAM.

Previously, 95 % of these sales were included in the FAC and 5 % were included in the RESRAM.

The limitation is effective for revenue requirements approved by the MoPSC after January 1, 2024.

The RESRAM permits Ameren Missouri to recover or refund, through customer rates, the difference between the cost of compliance, net of production and investment tax credits, with Missouri’s renewable energy standard and the amount set in base rates.

All sales from the High Prairie, Atchison, and Huck Finn energy centers are included in the RESRAM.

Customer rates are adjusted for the RESRAM on an annual basis without a traditional regulatory rate review, subject to MoPSC prudence reviews.

The difference between actual compliance costs and costs billed to customers in a given period is deferred as a regulatory asset or liability.

The deferred amount is either billed or refunded to customers in a subsequent period.

The deferred amount is either collected from, or refunded to, customers in a subsequent period.

RESRAM regulatory assets earn carrying costs at short-term interest rates.

The RESRAM permits Ameren Missouri to recover investments in wind generation and other renewables related to compliance with Missouri’s renewable energy standard, and earn a return at the applicable WACC on those investments not already provided for in customer rates or any other recovery mechanism, such as the renewable energy standard cost tracker.

The renewable energy standard cost tracker allows Ameren Missouri to defer differences between actual costs primarily associated with the Maryland Heights Energy Center and renewable energy credits obtained through a 102 -MW power purchase agreement with a wind farm operator, which expires in August 2024, and those costs included in customer rates.

The renewable energy standard cost tracker allows Ameren Missouri to defer differences between actual costs primarily associated with the Maryland Heights Energy Center and renewable energy credits obtained through a 102 -MW power purchase agreement with a wind farm operator, which expired in August 2024, and those costs included in customer rates.

The FAC permits Ameren Missouri to recover or refund, through customer rates, 95 % of the variance in net energy costs from the amount set in base rates without a traditional regulatory rate review, subject to MoPSC prudence reviews, with the remaining 5 % of changes retained by Ameren Missouri.

As such, Ameren Missouri’s results of operations are affected by the 5 % not recovered or refunded under the FAC.

The 95 % variance in net energy costs in a given period is deferred as a regulatory asset or liability, and either billed or refunded to customers in a subsequent period.

The 95 % variance in net energy costs in a given period is deferred as a regulatory asset or liability, and is either collected from, or refunded to, customers in a subsequent period.

FAC regulatory assets earn carrying costs at short-term interest rates.

Ameren Missouri’s base rates for electric service are required to be reset at least every four years to allow for continued use of the FAC.

The MEEIA permits Ameren Missouri to recover customer energy-efficiency program costs, the related lost electric margins, and any performance incentive through the MEEIA without a traditional regulatory rate review, subject to MoPSC prudence reviews.

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

Ameren Missouri will collect the amounts necessary to repay the bonds through a rider over approximately 15 years from the date of the December 2024 bond issuance.

The MEEIA permits Ameren Missouri to recover customer energy-efficiency and demand response program costs, the related lost electric revenues, and any performance incentive through the MEEIA without a traditional regulatory rate review, subject to MoPSC prudence reviews.

MEEIA assets earn carrying costs at short-term interest rates.

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The PGA allows Ameren Missouri to recover costs of natural gas purchased on behalf of its customers without a traditional regulatory rate review, subject to MoPSC prudence reviews.

These pass-through purchased gas costs do not affect Ameren Missouri’s natural gas margins, as any change in costs is offset by a corresponding change in revenues.

These pass-through purchased gas costs do not affect Ameren Missouri’s net income, as any change in costs is offset by a corresponding change in revenues.

The difference between actual natural gas costs and costs billed to customers in a given period is deferred as a regulatory asset or liability.

The deferred amount is either billed or refunded to customers in a subsequent period.

The deferred amount is either collected from, or refunded to, customers in a subsequent period.

PGA regulatory assets earn carrying costs at short-term interest rates.

The WNAR allows Ameren Missouri to adjust natural gas delivery service rates charged to residential customers without a traditional regulatory rate review when

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deviations from normal weather conditions cause natural gas revenues to vary from the related revenue requirement approved by the MoPSC in the previous regulatory rate review.

The WNAR allows Ameren Missouri to adjust natural gas delivery service rates charged to residential customers without a traditional regulatory rate review when deviations from normal weather conditions cause natural gas revenues to vary from the related revenue requirement approved by the MoPSC in the previous regulatory rate review.

The impact of deviations from normal weather on natural gas delivery service revenues billed to residential customers in a given period are deferred as a regulatory asset or liability.

WNAR regulatory assets earn carrying costs at short-term interest rates.

The deferred amount is either billed or refunded to residential customers in a subsequent period.

The deferred amount is either collected from, or refunded to, residential customers in a subsequent period.

The ICC regulates rates and other matters for Ameren Illinois’ electric distribution service and natural gas distribution businesses.

Ameren Illinois used the IEIMA formula framework to establish annual customer electric distribution service rates effective through 2023.

Under the framework, Ameren Illinois is allowed to reconcile its revenue requirement for customer rates established through 2023.

Ameren Illinois’ 2021, 2022, and 2023 revenues reflected each year’s actual recoverable costs, year-end rate base, and a return at the applicable WACC, with the ROE component based on the annual average of the monthly yields of the 30-year United States Treasury bonds plus 580 basis points.

The 2022 and 2023 revenue requirement reconciliation adjustments will be collected from customers within two years from the end of the reconciled year.

By law, the decoupling provisions extend beyond 2023, which ensures that Ameren Illinois’ electric distribution revenues authorized in a regulatory rate review are not affected by changes in sales volumes.

Pursuant to the CEJA, Ameren Illinois may elect to establish electric distribution service rates through either an MYRP or a traditional regulatory rate review.

See below for additional information regarding the MYRP approved by the ICC, which established rates effective for 2024 through 2027.

The rates Ameren Illinois charges customers for natural gas distribution service are established in a traditional regulatory rate review, which takes up to 11 months to complete, based on a future test year and the revenue requirement established in the review.

Ameren Illinois’ electric distribution service has cost recovery mechanisms in place that allow customer rates to be adjusted without an MYRP or a traditional regulatory rate review.

Ameren Illinois’ electric distribution service business has riders for power procurement and transmission services incurred on behalf of its customers, renewable energy credit compliance, zero emission credits, and certain environmental costs, as well as bad debt write-offs and the costs of certain asbestos-related claims not recovered in base rates.

This includes the RBA, which is described in more detail below, and riders for power procurement and transmission services incurred on behalf of its customers, renewable energy credit compliance, zero emission credits, customer generation rebate program costs, and certain environmental costs, as well as bad debt write-offs and the costs of certain asbestos-related claims not recovered in base rates.

These pass-through costs do not affect Ameren Illinois’ net income, as any change in costs is offset by a corresponding change in revenues.

Ameren Illinois’ cost recovery under any of its recovery mechanisms is subject to ICC prudence reviews.

Pursuant to the CEJA, Ameren Illinois may elect to establish electric distribution service rates through either an MYRP or a traditional regulatory rate review for 2024 and beyond.

See below for additional information regarding the MYRP approved by the ICC in December 2023, which established rates effective 2024 through 2027.

Under the 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.

Under the MYRP, Ameren Illinois is allowed to reconcile its actual electric distribution revenue requirement, as adjusted for certain cost variations, to the ICC-approved revenue requirement 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.

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The reconciliation cap also excludes costs recovered outside of base rates through riders, such as those described above and the electric energy-efficiency rider discussed below, among others.

Ameren Illinois’ existing riders remain effective and electric distribution service revenues continue to be decoupled from sales volumes under the MYRP.

The actual revenue requirement for a particular year incorporates Ameren Illinois’ year-end rate base and actual capital structure for such year, provided that the resulting revenue requirement does not exceed the 105 % reconciliation cap and the common equity ratio in such capital structure may not exceed that approved by the ICC in the MYRP.

Subject to the reconciliation cap, if a given year’s revenue amount collected from customers varies from the approved revenue requirement, an adjustment is made to electric operating revenues with an offset to a regulatory asset or liability to reflect that year’s actual revenue requirement, independent of actual sales volumes.

Ameren Illinois did not exceed the reconciliation cap for the 2024 revenue requirement, which is subject to final reconciliation and ICC review.

Subject to the reconciliation cap, if a given year’s actual revenue requirement collected from customers varies from the approved revenue requirement, an adjustment is made to electric operating revenues with an offset to a regulatory asset or liability to reflect that year’s actual revenue requirement.

The regulatory balance is then collected from, or refunded to, customers within two years from the end of the applicable annual period.

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However, Ameren Illinois recognizes the carrying cost of debt on these regulatory assets in revenue, instead of the applicable WACC, with the difference recognized in revenues when recovery of such regulatory assets is reflected in customer rates.

Ameren Illinois’ existing riders continue to be effective under the MYRP.

The RBA allows Ameren Illinois to adjust electric distribution service rates charged to customers under an MYRP or a traditional regulatory rate review when electric distribution revenues vary from the related revenue requirement approved by the ICC in the previous MYRP or traditional regulatory rate review.

If a given year’s actual revenue billed to customers varies from the approved revenue requirement as a result of sales volumes and/or wholesale and miscellaneous revenue, an adjustment is made to electric operating revenues with an offset to a regulatory asset or liability to reflect that year’s actual revenue.

RBA regulatory assets do not earn carrying costs or a return.

The regulatory balance is either collected from, or refunded to, customers within two years from the end of the applicable annual period.

Ameren Illinois used the IEIMA formula framework to establish annual customer electric distribution service rates effective through 2023.

Under the framework, Ameren Illinois was allowed to reconcile its revenue requirement for customer rates established through 2023.

Ameren Illinois’ 2022 and 2023 revenues reflected each year’s actual recoverable costs, year-end rate base, and a return at the applicable WACC, with the ROE component based on the annual average of the monthly yields of the 30-year United States Treasury bonds plus 580 basis points.

The 2022 revenue requirement reconciliation adjustment was collected from customers in 2024, and the 2023 adjustment will be collected in 2025.

Ameren Illinois’ electric customer energy-efficiency rider provides Ameren Illinois’ electric distribution service business with recovery of, and return on, energy-efficiency investments.

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

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

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

These performance metrics include improvements in service reliability in both the frequency and duration of outages, a reduction in peak loads, an increased percentage of spend with diverse suppliers, a reduction in disconnections for certain customers, and improved timeliness in response to customer requests for interconnection of distributed energy resources.

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

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The PGA allows Ameren Illinois to recover costs of natural gas purchased on behalf of its customers without a traditional regulatory rate review, subject to ICC prudence reviews.

These pass-through purchased gas costs do not affect Ameren Illinois natural gas margins, as any change in costs is offset by a corresponding change in revenues.

These pass-through purchased gas costs do not affect Ameren Illinois’ net income, as any change in costs is offset by a corresponding change in revenues.

The difference between actual natural gas costs and costs billed to customers in a given period is deferred as a regulatory asset or liability.

The deferred amount is either billed or refunded to customers in a subsequent period.

The deferred amount is either collected from, or refunded to, customers in a subsequent period.

PGA regulatory assets earn carrying costs at short-term interest rates.

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The difference between allowed sales revenues and amounts billed to customers in a given period is deferred as a regulatory asset or liability.

The deferred amount is collected from, or refunded to, customers in a subsequent period.

The deferred amount is either collected from, or refunded to, customers in a subsequent period.

VBA regulatory assets for a given year that are not fully collected by the end of the following year begin earning carrying costs at short-term interest rates.

The QIP expired in December 2023.

Previously, it provided Ameren Illinois with recovery of, and a return on, qualifying natural gas infrastructure investments that were placed in service between regulatory rate reviews.

Infrastructure investments under the QIP earned a return at the applicable WACC.

Eligible natural gas investments included projects to improve safety and reliability and modernization investments, such as smart meters.

The deferrals were recorded as a regulatory asset, with recovery beginning two months after the qualifying natural gas plant was placed in service and continuing until such plant was included in base rates in a natural gas delivery service rate order.

Ameren Illinois’ QIP was subject to a rate impact limitation of a cumulative 4 % per year since the most recent delivery service rate order, with no single year exceeding 5.5 %.

Ameren Illinois did not exceed the rate impact limitation in 2023.

Upon issuance of a natural gas delivery service rate order, QIP rate base was transferred to base rates and the QIP was reset to zero .

Reconciliation hearings to determine the accuracy and prudence of natural gas capital investments recovered under the QIP are still ongoing.

See below for additional information on the recovery of capital investments that were made during 2020.

The FERC regulates rates and other matters for Ameren Illinois’ transmission business and ATXI, as well as for Ameren Missouri.

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In addition, the FERC has approved transmission rate incentives, including a 50 -basis-point incentive adder to the allowed base ROE for Ameren Illinois and ATXI for participation in an RTO.

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Proceedings and Updates

June 2023 MoPSC Electric Rate Order

In June 2023, the MoPSC issued an order in Ameren Missouri’s 2022 electric service regulatory rate review, approving a nonunanimous stipulation and agreement.

The order resulted in an increase of $ 140 million to Ameren Missouri’s annual revenue requirement for electric retail service.

The approved revenue requirement was based on infrastructure investments as of December 31, 2022, and included an extension of the depreciable lives of the Sioux Energy Center’s assets from 2028 to 2030.

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

The order provides for the continued use of the FAC and trackers for pension and postretirement benefits, uncertain income tax positions, certain excess deferred income taxes, and renewable energy standard compliance costs that the MoPSC previously authorized in earlier electric rate orders, as well as the use of an electric property tax tracker.

It also includes a tracker for the utilization of production and investment tax credits or proceeds from the sale of such tax credits allowed under the IRA.

The order increased the annualized base level of net energy costs pursuant to the FAC by approximately $ 40 million from the base level established in the MoPSC’s December 2021 electric rate order.

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

On an annualized basis, these changes reflect approximate increases in “Depreciation and amortization” of $ 90 million and “Other income, net”, of $ 100 million, related to non-service pension and postretirement benefit income, on Ameren’s and Ameren Missouri’s consolidated statements of income.

The new rates became effective on July 9, 2023.

Solar Generation Facilities

During 2022 and 2023, Ameren Missouri, and certain subsidiaries of Ameren Missouri, entered into agreements to acquire and/or construct various solar generation facilities, which, if placed in-service, would be eligible for recovery under the PISA.

2024 Electric Service Regulatory Rate Review

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

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

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

Ameren Missouri also requested the continued use of all of its existing riders and trackers.

The electric rate increase request reflects the following:

• increased infrastructure investments made under Ameren Missouri’s Smart Energy Plan, including increased cost of capital and depreciation expense.

Included in these investments are 500 megawatts of solar generation investment for the Boomtown, Cass County and Huck Finn projects along with investments in the Callaway nuclear energy center and other dispatchable generation to support a reliable, low-cost and cleaner mix of energy resources;

• decreased costs resulting from the retirement of the Rush Island Energy Center;

• decreased costs related to the extension of the retirement date of the Sioux Energy Center from 2030 to 2032 to ensure reliability.

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

The MoPSC staff’s recommendation includes adjustments for lower off-system sales revenue, production tax credits, and renewable energy credits as a result of the curtailed nighttime operations at the High Prairie Energy Center to limit its impact on protected species.

See Note 14 – Commitments and Contingencies for additional information on the curtailed nighttime operations at the High Prairie Energy Center.

The MoPSC staff supported the continued use of all of Ameren Missouri’s existing riders and trackers.

In December 2024, the MoOPC challenged 25 % to 45 % of the costs and requested return associated with the High Prairie Energy Center investment included in Ameren Missouri’s requested revenue requirement as a result of the curtailed nighttime operations at the energy center discussed above.

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

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

2024 Natural Gas Delivery Service Regulatory Rate Review

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

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

The request includes the continued use of all of Ameren Missouri’s existing riders and trackers.

The natural gas rate increase request reflects investments in our existing natural gas infrastructure to ensure the safe delivery of natural gas.

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

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

Generation Facilities

Ameren Missouri, and certain subsidiaries of Ameren Missouri, are parties to agreements to acquire and/or construct various generation facilities.

The solar generation facilities are eligible for recovery under the PISA.

The Castle Bluff Natural Gas Project is eligible for recovery under the post-construction cost deferral discussed below.

The following table provides information with respect to each agreement:

Solar Project (a)(b)

Solar Project (b)(c)

Solar Project (d)

Solar Project (c)

Solar Project (d)

Bowling Green

Solar Project (d)

Agreement type Build-transfer Build-transfer Build-transfer (e)

Development-transfer (e)(f)

Self-build (e)(g)

Facility size 200 -MW

Status of MoPSC CCN Approved February 2023 Approved April 2023 Filed June 2023 (h)

Filed June 2023 (h)

Status of FERC approval of acquisition Received March 2023 Received October 2023 Expect to request by mid-2024 Not applicable Not applicable Not applicable

Earliest completion date (i)

Fourth quarter 2024 Fourth quarter 2024 Mid-2026 Fourth quarter 2024 Fourth quarter 2025 First quarter 2026

(a) The Huck Finn Solar Project is expected to support Ameren Missouri’s compliance with the state of Missouri’s renewable energy standard.

Investments in the project will be eligible for recovery under the RESRAM.

(b) These projects collectively represent approximately $ 0.65 billion of expected capital expenditures.

(c) The Boomtown and Cass County solar projects are expected to support Ameren Missouri’s transition to renewable energy generation and serve customers under the Renewable Solutions Program discussed below.

(d) These solar projects are expected to support Ameren Missouri’s transition to renewable energy generation.

(e) These projects, and applicable agreements, are subject to the issuance of a CCN by the MoPSC.

(f) Ameren Missouri entered into an agreement to acquire the Cass County Solar Project, which includes project design, land rights, and engineering, procurement, and construction agreements for a solar generation facility.

Ameren Missouri will construct the facility after obtaining a CCN from the MoPSC and acquiring the project.

Acquisition of the project is expected by mid-2024.

(g) Ameren Missouri entered into engineering, procurement, and construction agreements to construct these solar projects.

(h) In February 2024, Ameren Missouri, the MoPSC staff, and the MoOPC filed a nonunanimous stipulation and agreement requesting the MoPSC approve Ameren Missouri’s requests for CCNs for the Split Rail, Vandalia, and Bowling Green solar projects.

The stipulation and agreement also requests MoPSC approval of the CCN request for the Cass County Solar Project conditioned upon the facility supporting the Renewable Solutions Program discussed below and full subscription of the portion of the program supported by this facility, subject to certain other terms and conditions.

The remaining intervenors did not object to the agreement.

Ameren Missouri expects a decision by the MoPSC in March 2024.

(i) Expected completion dates are dependent on the timing of regulatory approvals, among other things.

Renewable Solutions Program

The April 2023 MoPSC order approving the CCN for the Boomtown Solar Project also approved Ameren Missouri’s Renewable Solutions Program and a tariff related to participation in the program.

The program allows certain commercial, industrial, and governmental customers who enroll in the program to receive up to 100 % of their energy from renewable resources.

Separate enrollment occurs for each

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renewable resource serving customers under the program.

Collection under the tariff will not begin until the Boomtown Solar Project is placed in service.

MoPSC Staff Review of Planned Rush Island Energy Center Retirement

In February 2022, the MoPSC issued an order directing the MoPSC staff to review Ameren Missouri’s planned accelerated retirement of the Rush Island Energy Center as a result of the NSR and Clean Air Act Litigation discussed in Note 14 – Commitments and Contingencies.

The MoPSC staff’s review includes potential impacts on the reliability and cost of Ameren Missouri’s service to its customers;

Ameren Missouri’s plans to mitigate the customer impacts of the accelerated retirement;

and the prudence of Ameren Missouri’s actions and decisions with regard to the Rush Island Energy Center, among other things.

In April 2022, the MoPSC staff filed an initial report with the MoPSC in which the staff concluded early retirement of the Rush Island Energy Center may cause reliability concerns.

The MoPSC staff is under no deadline to complete this review.

Ameren Missouri is unable to predict the results of this matter.

Results of the review could be used in the securitization proceeding discussed below, which could have a material adverse effect on the results of operations, financial position, and liquidity of Ameren and Ameren Missouri if Ameren Missouri is not allowed to recover Rush Island costs through securitization.

Agreement type Facility size Status of MoPSC CCN Status of FERC approval of acquisition In-service date (a)

Huck Finn Solar Project (b)(c)

Build-transfer 200 -MW

Approved February 2023 Received March 2023 December 2024

Boomtown Solar Project (c)(d)

Build-transfer 150 -MW

Approved April 2023 Received October 2023 December 2024

Cass County Solar Project (c)(d)

Development-transfer 150 -MW

Approved June 2024 Not applicable December 2024

Vandalia Solar Project (e)(f)

Self-build 50 -MW

Approved March 2024 Not applicable Fourth quarter 2025

Bowling Green Solar Project (e)(f)

Self-build 50 -MW

Approved March 2024 Not applicable First quarter 2026

Split Rail Solar Project (e)(f)

Build-transfer 300 -MW

Approved March 2024 Received November 2024 Mid-2026

Castle Bluff Natural Gas Project (e)

Self-build 800 -MW

Approved October 2024 (g)

Not applicable Fourth quarter 2027

(a) In-service dates are dependent on the timing of construction completion, among other things.

The assets of the Huck Finn, Boomtown, and Cass County solar projects were placed in service in December 2024.

(b) The Huck Finn Solar Project is expected to support Ameren Missouri’s compliance with the state of Missouri’s renewable energy standard.

Investments in the project are eligible for recovery under the RESRAM.

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

(d) The Boomtown and Cass County solar projects are expected to support Ameren Missouri’s transition to renewable energy generation and serve customers under the Renewable Solutions Program, which allows certain commercial, industrial, and governmental customers who enroll in the program to receive up to 100 % of their energy from renewable resources.

(e) These projects collectively represent approximately $ 1.7 billion of expected capital expenditures.

(f) These solar projects are expected to support Ameren Missouri’s transition to renewable energy generation.

(g) For additional information see Castle Bluff Natural Gas Project CCN and Post-Construction Cost Deferral below.

Castle Bluff Natural Gas Project CCN and Post-Construction Cost Deferral

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

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

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

Securitization of Rush Island Energy Center Costs

In November 2023, Ameren Missouri petitioned the MoPSC for a financing order to authorize the issuance of securitized utility tariff bonds to finance $ 519 million of costs related to the planned accelerated retirement of the Rush Island Energy Center, which includes the expected remaining unrecovered net plant balance associated with the facility.

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

In February 2024, the MoPSC staff filed a response to Ameren Missouri’s petition that stated Ameren Missouri’s decision to accelerate the retirement of the Rush Island Energy Center was prudent and largely supported Ameren Missouri’s securitization request.

However, the MoPSC staff claimed Ameren Missouri’s prior actions that resulted in the adverse ruling in the NSR and Clean Air Act Litigation discussed in Note 14 – Commitments and Contingencies were imprudent and recommended that the impact of those actions on customers be considered in future rate reviews.

If Ameren Missouri is not allowed to recover Rush Island Energy Center costs through securitization or if future rate reviews result in revenue reductions based on Ameren Missouri’s prior actions that resulted in the adverse ruling in the NSR and Clean Air Act Litigation, it could have a material adverse effect on the results of operations, financial position, and liquidity of Ameren and Ameren Missouri.

Ameren Missouri expects a decision by the MoPSC by the end of June 2024, but cannot predict the ultimate outcome of this regulatory proceeding.

In August 2023, the MoPSC issued an order approving a nonunanimous stipulation and agreement to extend Ameren Missouri’s MEEIA 2019 program for an additional year through 2024.

For 2024, the order approved the establishment of a portfolio of customer energy-efficiency programs and performance incentives that will provide Ameren Missouri an opportunity to earn revenues, including $ 12 million of performance incentive revenues if Ameren Missouri achieves certain program spending goals.

In 2024, Ameren Missouri expects to invest $ 76 million in energy-efficiency programs.

In December 2023 and 2022, Ameren Missouri achieved certain energy-efficiency spending goals for the MEEIA 2019 program.

As a result of achieving these spending goals and MoPSC orders issued in August 2022 and September 2021, Ameren Missouri recognized performance incentive revenues of $ 12 million, $ 22 million, and $ 9 million in 2023, 2022, and 2021, respectively.

In January 2024, Ameren Missouri filed a proposed customer energy-efficiency plan with the MoPSC under the MEEIA.

This filing proposed a three-year plan, which includes a portfolio of customer energy-efficiency programs, along with the continued use of the MEEIA rider, which allows Ameren Missouri to collect from, or refund to, customers any difference in actual MEEIA program costs and related lost electric margins and the amounts collected from customers.

If the plan is approved, Ameren Missouri intends to invest $ 123 million annually in the proposed customer energy-efficiency programs from 2025 to 2027.

In addition, Ameren Missouri requested performance incentives applicable to each plan year to earn revenues by achieving certain customer energy-efficiency savings and target spending goals.

If 100 % of the goals are achieved, Ameren Missouri would earn performance incentive revenues totaling $ 56 million over the three-year plan.

Ameren Missouri also requested additional performance incentives applicable to each plan year totaling up to $ 14 million over the three-year plan, if Ameren Missouri exceeds 100 % of the goals.

Ameren Missouri expects a decision by the MoPSC by October 2024 but cannot predict the ultimate outcome of this regulatory proceeding.

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

The securitized tariff bonds were issued in December 2024.

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

The MoPSC did not make a determination regarding the prudency of Ameren Missouri's prior actions that resulted in the adverse ruling in the NSR and Clean Air Act litigation discussed in Note 14 – Commitments and Contingencies, however, claims regarding such actions could be considered in future regulatory proceedings.

If future regulatory proceedings result in revenue reductions based on Ameren Missouri’s prior actions that resulted in the adverse ruling in the NSR and Clean Air Act litigation, it could have a material adverse effect on the results of operations, financial position, and liquidity of Ameren and Ameren Missouri.

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

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

See Note 5 – Long-term Debt and Equity Financings for additional information on the securitized tariff bonds issuance.

In 2024, 2023, and 2022, Ameren Missouri achieved certain energy-efficiency spending goals for the MEEIA 2019 program.

As a result of achieving these spending goals and MoPSC order issued in August 2022, Ameren Missouri recognized performance incentive revenues of $ 13 million, $ 12 million, and $ 22 million, respectively.

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

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

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

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

MISO Long-Range Transmission Projects CCN

In 2022, the MISO approved the first tranche of projects related to a preliminary long-range transmission planning roadmap of projects through 2039.

A portion of these projects were assigned or awarded via a competitive bid process to various utilities, including Ameren.

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

Decisions by the MoPSC are expected in 2025.

In December 2023, the ICC issued an order in Ameren Illinois' MYRP proceeding approving base rates for electric distribution services for 2024 through 2027 and rejecting Ameren Illinois' Grid Plan, which was addressed as part of the MYRP proceeding.

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

The ICC concluded that the proposed Grid Plan did not meet certain statutory

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requirements and directed Ameren Illinois to file a revised Grid Plan within three months .

Ameren Illinois expects to file a revised Grid Plan with the ICC in March 2024, and also expects to file a request to update the associated MYRP revenue requirements for 2024 through 2027 in the first half of 2024.

The ICC will be under no deadline to act on the revised Grid Plan when filed.

The December 2023 order adopted an alternative methodology to establish a rate base and revenue requirements for the years 2024 through 2027, using the 2022 year-end rate base approved by the ICC in its 2022 electric distribution service revenue requirement reconciliation adjustment order discussed below.

This rate base will remain in effect through 2027, unless subsequently changed by the ICC in the rehearing discussed below or if approval of a revised Grid Plan results in an update of each year’s revenue requirement.

In January 2024, Ameren Illinois filed a request for rehearing of the ICC's December 2023 order.

The filing contended that the use of the 2022 year-end rate base for each year of the MYRP, until a revised Grid Plan is approved, is unlawful and not in compliance with the CEJA.

In addition, the filing requested the ICC revise the order to include an allowed ROE of at least 9.82 % for each year of the MYRP and include a base level of investments to maintain grid reliability in each year of the MYRP, among other things.

In January 2024, the ICC partially denied Ameren Illinois’ rehearing request by denying Ameren Illinois’ request regarding the allowed ROE, and granting Ameren Illinois’ request to consider whether it is appropriate to use the 2022 year-end rate base for each year of the MYRP and to include a base level of investments to maintain grid reliability in each year of the MYRP.

Additionally, the scope of the rehearing will include a review of certain operations and maintenance expenses in each year of the MYRP.

In February 2024, Ameren Illinois filed its request in the rehearing proceeding, which proposed updated revenue requirements and annual rate base amounts to reflect a base level of investments to maintain grid reliability for 2024 through 2027.

An ICC decision in this rehearing is expected by late June 2024.

Also, in January 2024, Ameren Illinois filed an appeal of the December 2023 ICC order and the partial denial of Ameren Illinois’ request for rehearing to the Illinois Appellate Court for the Fifth Judicial District.

The court is under no deadline to address the appeal.

Ameren Illinois cannot predict the ultimate outcome of the revised Grid Plan filing, its request to update the associated MYRP revenue requirements for 2024 through 2027, the rehearing proceeding, or the appeal to the Illinois Appellate Court for the Fifth Judicial District.

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

Year Revenue Requirement (in millions) ROE Capital Structure Common Equity Percentage Annual Rate Base (in billions)

ICC’s December 2023 MYRP Order:

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

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

In January 2024, the ICC partially denied a rehearing requested by Ameren Illinois to revise the allowed ROE in the December 2023 order and granted Ameren Illinois’ rehearing request to reconsider the rate base for each year of the MYRP and to include a base level of investments to maintain grid reliability in each year of the MYRP.

In June 2024, the ICC issued an order on Ameren Illinois’ rehearing request, which revised the rate bases for Ameren Illinois’ MYRP test years to include investments for 2023 through 2027, among other things.

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

For additional information on the ICC’s June 2024 rehearing order, see the table below.

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

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

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

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

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

In December 2024, the ICC issued an order in connection with Ameren Illinois’ revised Grid Plan and revised MYRP for electric distribution service for 2024 through 2027.

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.

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

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

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

The following table presents the approved revenue requirements and average annual rate base in the ICC’s December 2024 MYRP order and the ICC’s June 2024 rehearing order:

Year Revenue Requirement (in millions) Average Annual Rate Base (in billions)

ICC’s December 2024 MYRP Order (a) :

2024 $ 1,206 $ 4.2

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2027 $ 1,422 $ 4.8

Ameren Illinois’ February 2024 Rehearing Request Filing:

2024 $ 1,214 (a) 50 % $ 4.2

2025 $ 1,300 (a) 50 % $ 4.5

2026 $ 1,371 (a) 50 % $ 4.7

2027 $ 1,420 (a) 50 % $ 4.9

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

The approved revenue requirements in the ICC’s December 2023 order represent a cumulative increase of $ 142 million compared to a cumulative increase of $ 444 million requested by Ameren Illinois in its revised September 2023 MYRP filing.

The ICC’s December 2023 order did not utilize a phase-in provision that is permitted by the CEJA for any initial rate increase.

ICC’s June 2024 Rehearing Order (a) :

2024 $ 1,196 $ 4.0

2025 $ 1,282 $ 4.3

2026 $ 1,350 $ 4.5

2027 $ 1,397 $ 4.7

(a) Based on an allowed ROE of 8.72 % and a capital structure composed of 50 % common equity.

The ROE is under appeal, as discussed above.

New rates became effective in December 2024.

2023 Electric Distribution Revenue Requirement Reconciliation Adjustment Order

In November 2023, the ICC issued an order approving Ameren Illinois’ 2022 electric distribution service revenue requirement reconciliation adjustment filing.

This order approved a reconciliation adjustment of $ 110 million, which reflected Ameren Illinois’ actual 2022 recoverable costs, year-end rate base of $ 3.9 billion, and a capital structure composed of 50 % common equity.

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

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

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

In addition, Ameren Illinois will file its 2023 electric distribution service revenue requirement reconciliation with the ICC by May 2024, which will reflect its 2023 year-end rate base.

The 2023 reconciliation adjustment, if approved by the ICC, will be collected from customers in 2025.

Electric Customer Energy-Efficiency Investments

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

The order was based on a projected 2024 year-end rate base of $ 394 million.

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

2025 Natural Gas Delivery Service Rate Review

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

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

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

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

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

2023 Natural Gas Delivery Service Rate Order

4 unchanged sentences

The filing requested the ICC revise the order to include an allowed ROE of at least 9.89 %, a capital structure composed of 52 % common equity, and a reversal of the approximately $ 93 million reduction of planned distribution and transmission capital investments included in the order, among other things.

In January 2024, the ICC denied Ameren Illinois’ rehearing request.

Subsequently, in January 2024, Ameren Illinois filed an appeal of the November 2023 ICC order and the January 2024 ICC denial of Ameren Illinois’ request for rehearing to the Illinois Appellate Court for the Fifth Judicial District.

The court is under no deadline to address the appeal.

Ameren Illinois cannot predict the ultimate outcome of this appeal.

The ICC’s November 2023 natural gas delivery service rate order also required Ameren Illinois to submit a plan outlining how it expects to comply with new PHMSA rules for natural gas transmission pipelines, including proposing a capital expenditures plan necessary to meet the new rules.

In February 2024, Ameren Illinois filed its plan with the ICC, which included its proposal of natural gas transmission capital expenditures necessary to achieve compliance with the PHMSA rules.

The plan includes delays to certain natural gas transmission capital expenditures from 2024 to subsequent years to align with the November 2023 ICC order.

The ICC is under no obligation to issue an order regarding Ameren Illinois’ plan.

In January 2024, the ICC denied Ameren Illinois’ rehearing request, and Ameren Illinois filed an appeal with the Illinois Appellate Court for the Fifth Judicial District.

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

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

Future of Gas Proceeding

The ICC’s November 2023 natural gas delivery service rate order discussed above directed the ICC staff to develop a plan for a future of gas proceeding.

All of the Illinois natural gas utilities subject to ICC regulation will be included in this proceeding, which will explore issues involved with decarbonization of the natural gas distribution system in light of the state of Illinois’ goal of economy-wide 100 % clean energy by 2050, pursuant to the CEJA.

Some of the issues expected to be addressed include the mitigation of any natural gas distribution stranded assets, the role of energy efficiency in decarbonization, and the associated impacts of natural gas decarbonization to the electric distribution system, among others.

All of the Illinois natural gas utilities subject to ICC regulation are included in this proceeding, which is exploring issues involving the decarbonization of the natural gas distribution system in light of the state of Illinois’ goal of economy-wide 100 % clean energy by

2050, pursuant to the CEJA.

Some of the issues being addressed include the mitigation of any natural gas distribution stranded assets, the role of energy efficiency in decarbonization, and the associated impacts of natural gas decarbonization to the electric distribution system, among others.

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

QIP Reconciliation Hearing

In March 2021, Ameren Illinois filed a request with the ICC for a reconciliation hearing to determine the accuracy and prudence of natural gas capital investments recovered under the QIP rider during 2020.

In October 2023, the Illinois Attorney General’s office challenged the recovery of capital investments that were made during 2020, alleging that the ICC should disallow approximately $ 53 million in natural gas capital investments as improper and imprudent, providing a potential over-recovery of approximately $ 3 million in 2020.

In October 2023, the ICC staff filed testimony that supports the prudence and reasonableness of the capital investments made during 2020.

In 2021, Ameren Illinois filed a request with the ICC to initiate a reconciliation proceeding of natural gas capital investments recovered under the QIP rider during 2020.

In September 2024, the Illinois Attorney General’s office challenged the recovery of capital investments that were made during 2020, alleging that the ICC should disallow approximately $ 30 million in natural gas capital investments as improper and imprudent, resulting in a potential over-recovery of an immaterial amount by Ameren Illinois in 2020.

In October 2023, and again in September 2024, the ICC staff filed testimony that supports the prudence and reasonableness of the capital investments made during 2020.

Ameren Illinois’ 2020 QIP rate recovery request under review by the ICC was within the rate increase limitations allowed by law.

The ICC is under no deadline to issue an order in this proceeding.

Ameren Illinois cannot predict the ultimate outcome of this regulatory proceeding.

RTO Cost-Benefit Study

In July 2022, an Illinois law prohibiting the state’s oversight of certain electric utilities’ choice of RTO membership ceased to be effective.

Given the change in law and the high prices resulting from the MISO’s April 2022 capacity auction, the ICC issued an order requiring Ameren Illinois to perform a cost-benefit study of continued participation in the MISO compared to participation in PJM Interconnection LLC, another RTO.

In July 2023, Ameren Illinois filed its cost-benefit study with the ICC.

The cost-benefit study examined the impacts of participation in each RTO, including reliability, resiliency, affordability, and environmental impacts, among other things, for a period of five to 10 years beginning June 2024.

The study concluded that continued participation in the MISO was prudent and more cost-beneficial than participation in PJM Interconnection LLC.

Intervenor comments on the study were filed in October 2023 and reply comments were filed in November 2023.

In January 2024, the ICC staff submitted a report recommending the ICC not take any action with regard to changing Ameren Illinois’ RTO membership.

The ICC is under no obligation to issue an order related to the cost-benefit study.

In addition, 2021 through 2023 reconciliation proceedings are still ongoing.

Ameren Illinois cannot predict the ultimate outcome of these regulatory proceedings.

MISO Long-Range Transmission Projects CCN

In February 2024, Ameren Illinois and ATXI filed a request for a CCN with the ICC related to the portion of the MISO long-range transmission projects discussed below that are expected to be constructed within the ICC’s jurisdiction.

A decision by the ICC is expected by February 2025.

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MISO Transmission Rate Incentives

In July 2022, the MISO approved the first tranche of projects related to a preliminary long-range transmission planning roadmap of projects through 2039.

A portion of these projects were assigned to various utilities, including Ameren.

The projects assigned to Ameren are estimated to cost approximately $ 1.8 billion, based on the MISO’s cost estimate.

In October 2023, the FERC issued an order that approved transmission rate incentives relating to the projects assigned to Ameren.

The incentives will allow construction work in progress to be included in rate base for projects constructed by ATXI, thereby improving the timeliness of cash recovery, and would allow recovery of prudently incurred costs, subject to FERC approval, for any portion of the projects if they are abandoned for reasons beyond the control of Ameren.

As a result of the order, ATXI will not capitalize allowance for funds used during construction on the related projects.

FERC Complaint Cases

In 2022, the MISO approved the first tranche of projects related to a preliminary long-range transmission planning roadmap of projects through 2039.

A portion of these projects were assigned or awarded via a competitive bidding process to various utilities, including Ameren.

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

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

FERC ROE Complaint Cases

Since November 2013, the allowed base ROE for FERC-regulated transmission rate base under the MISO tariff has been subject to customer complaint cases and has been changed by various FERC orders.

In May 2020, the FERC issued an order, which set the allowed base ROE to 10.02 %, and required refunds, with interest, for the periods November 2013 to February 2015 and from late September 2016 forward.

In May 2020, the FERC issued an order, which set the allowed base ROE to 10.02 % and required refunds, with interest, for the periods from November 2013 to February 2015 and from late September 2016 forward.

Ameren and Ameren Illinois paid these refunds, including interest, by March 31, 2022.

In June and July 2020, Ameren Missouri, Ameren Illinois, and ATXI, as well as various customers, petitioned the United States Court of Appeals for the District of Columbia Circuit for review of the May 2020 order, challenging certain aspects of the new ROE methodology established.

In 2020, Ameren Missouri, Ameren Illinois, and ATXI, as well as various customers, petitioned the United States Court of Appeals for the District of Columbia Circuit for review of the May 2020 order, challenging certain aspects of the new ROE methodology established.

The petition filed by Ameren Missouri, Ameren Illinois, and ATXI challenged the refunds required for the period from September 2016 to May 2020.

1 unchanged sentence

The court elected not to rule on the issues raised by Ameren Missouri, Ameren Illinois, and ATXI.

The currently allowed base ROE of 10.02 % will remain effective for customer billings, but the transmission rates charged during previous periods and the currently effective rates may be subject to refund if the base ROE is changed by the FERC in a future order.

The FERC is under no deadline to issue an order related to these proceedings.

A 50 -basis-point change in the FERC-allowed ROE would affect Ameren’s and Ameren Illinois’ annual revenue by an estimated $ 21 million and $ 15 million, respectively, based on each company’s 2024 projected rate base.

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In October 2024, the FERC issued an order, which decreased the allowed base ROE from 10.02 % to 9.98 % and required refunds, with interest, for the same periods covered by the May 2020 order.

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

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

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

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

As a result of the October 2024 order, Ameren and Ameren Illinois recognized reductions to "Operating Revenues – Electric" on their statements of income of $ 10 million and $ 7 million, respectively, and recognized expense of $ 2 million and $ 1 million, respectively, in “Interest charges” on their statements of income in 2024.

As of December 31, 2024, Ameren and Ameren Illinois had recorded liabilities in "Current regulatory liabilities" on their balance sheets of $ 12 million and $ 8 million, respectively, to reflect the expected refunds, including interest, associated with the allowed base ROE set by the October 2024 order.

Regulatory Assets and Liabilities

7 unchanged sentences

$ 41 $ — $ 41 $ 72 $ — $ 72

Under-recovered Illinois electric power costs (b)

MTM derivative losses (b)

15 88 103 25 143 168

Under-recovered PGA (b)(c)

IEIMA revenue requirement reconciliation adjustment (c)(d)

— 139 139 — 239 239

MTM derivative losses (d)

MYRP revenue requirement reconciliation adjustment (d)(e)

— 24 24 — — —

IEIMA revenue requirement reconciliation adjustment (e)(f)

Under-recovered RBA (f)

— 22 22 — — —

13 unchanged sentences

— 43 43 — 50 50

Storm costs (f)(n)

Storm costs (d)(n)

— 18 18 — 27 27

Allowance for funds used during construction for pollution control equipment (f)(o)

Customer generation rebate program (d)(o)

— 89 89 — 54 54

Customer generation rebate program (f)(p)

464 — 464 386 — 386

Rush Island Energy Center securitization (q)

465 — 465 — — —

2 unchanged sentences

26 — 26 39 — 39

FEJA energy-efficiency rider (f)(t)

Energy-efficiency rider (d)(t)

— 576 576 — 500 500

6 unchanged sentences

Regulatory liabilities:

Over-recovered Illinois electric power costs (b)

Over-recovered Illinois electric power costs (v)

— 34 34 — 36 36

Over-recovered PGA (b)

Over-recovered PGA (v)

2 33 35 7 33 40

MTM derivative gains (d)

MTM derivative gains (b)

10 6 16 19 3 22

1 unchanged sentence

1,040 679 1,804 999 724 1,809

Cost of removal (v)

Cost of removal (w)

1,118 1,115 2,294 1,098 1,038 2,186

691 — 691 524 — 524

Bad debt rider (j)

Pension and postretirement benefit costs (y)

202 156 358 202 144 346

Pension and postretirement benefit costs (x)

Pension and postretirement benefit costs tracker (z)

70 — 70 111 — 111

Pension and postretirement benefit costs tracker (y)

Renewable energy credits and zero emission credits (aa)

— 586 586 — 489 489

Renewable energy credits and zero emission credits (z)

Certain Rush Island Energy Center costs (ab)

66 — 66 — — —

5 unchanged sentences

Specific accumulation periods aggregate the under-recovered costs over four months , any related adjustments that occur over the following four months , and the recovery from customers that occurs over the next eight months .

(b) Under-recovered or over-recovered costs from utility customers.

Amounts will be recovered from, or refunded to, customers within one year of the deferral.

(c) As a result of the significant increase in customer demand and prices for natural gas and electricity experienced in mid-February 2021 due to extremely cold weather, for the month of February 2021, Ameren Missouri had under-recovered costs under its PGA clause of $ 53 million.

Pursuant to an October 2021 MoPSC order, the collection period for Ameren Missouri’s cumulative PGA under-recovery as of August 2021, which included the February 2021 under-recovery, was extended from 12 months to 36 months, beginning November 2021.

(d) Deferral of commodity-related derivative MTM losses or gains.

(b) Deferral of commodity-related derivative MTM losses or gains.

See Note 7 – Derivative Financial Instruments for additional information.

(e) The difference between Ameren Illinois’ electric distribution service annual revenue requirement calculated under the IEIMA performance-based formula ratemaking framework and the revenue requirement included in customer rates for that year.

(c) The difference between Ameren Illinois’ electric distribution service annual revenue requirement calculated under the IEIMA performance-based formula ratemaking framework and the revenue requirement included in customer rates for that year.

The under-recovery will be recovered from customers with a return at the applicable WACC within two years .

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(f) These assets earn a return at the applicable WACC.

(d) These assets earn a return at the applicable WACC.

(e) The difference between Ameren Illinois' actual electric distribution revenue requirement, as adjusted for certain cost variations, and the ICC-approved revenue requirement, subject to a reconciliation cap.

The under-recovery will be recovered from customers with a return at the applicable WACC within two years .

(f) Under-recovered electric distribution service revenue caused by sales volume and/or wholesale and miscellaneous revenue deviations from the related revenue requirement approved by the ICC for a given year.

The under-recovery will be recovered from customers within two years .

(g) Ameren Illinois’ and ATXI’s annual revenue requirement reconciliation calculated pursuant to the FERC’s electric transmission formula ratemaking framework.

2 unchanged sentences

Each year’s amount will be recovered from customers from April through December of the following year.

(i) The regulatory assets represent amounts that will be recovered from customers for deferred income taxes related to the equity component of allowance for funds used during construction and the effects of tax rate increases.

The regulatory liabilities represent amounts that will be refunded to customers for excess deferred income taxes related to depreciation differences, other tax liabilities, and the unamortized portion of investment tax credits all recorded at rates in excess of current statutory rates.

Amounts associated with the equity component of allowance for funds used during construction and the unamortized portion of investment tax credits will be amortized over the expected life of the related assets.

The regulatory liabilities represent amounts that will be refunded to customers for excess deferred income taxes related to depreciation differences caused by a decrease in the statutory rates, other tax liabilities, and amounts related to the unamortized portion of investment tax credits.

Amounts associated with the equity component of allowance for funds used during construction, the securitization of the Rush Island Energy Center, and amounts related to the unamortized portion of investment tax credits will be amortized over the expected life of the related assets.

For net regulatory liabilities related to deferred income taxes recorded at rates other than the current statutory rate, the weighted-average remaining amortization periods at Ameren, Ameren Missouri, and Ameren Illinois are 39 , 30 , and 46 years.

In addition, the regulatory liabilities for Ameren Missouri include a regulatory recovery mechanism for the difference between production and investment tax credits or proceeds from the sale of such tax credits allowed under the IRA and the level of such tax credits included in customer rates.

The period of refund varies based on MoPSC approval in a regulatory rate review.

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

(j) A rider for the difference between the level of bad debt write-offs, net of any subsequent recoveries, incurred by Ameren Illinois and the level of such costs included in electric distribution and natural gas delivery service rates.

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See Note 14 – Commitments and Contingencies for additional information.

(n) Storm costs from 2020 through 2023 deferred in accordance with the IEIMA.

(n) Storm costs from 2020 through 2023 deferred in accordance with the IEIMA and MYRP.

These costs are being amortized over five-year periods beginning in the year the storm occurred.

(o) The MoPSC’s May 2010 electric rate order allowed Ameren Missouri to record an allowance for funds used during construction for pollution control equipment at its Sioux Energy Center until the cost of that equipment was included in customer rates beginning in 2011.

These costs are being amortized over the expected life of the Sioux Energy Center, currently through 2030.

(p) Costs associated with Ameren Illinois’ customer generation rebate program.

(o) Costs associated with Ameren Illinois’ customer generation rebate program.

Costs are amortized over a 15-year period, beginning in the year rebates are paid.

(q) Under the PISA, Ameren Missouri is permitted to defer and recover 85 % of the depreciation expense and earn a return at the applicable WACC on investments in certain property, plant, and equipment placed in service and not included in base rates.

(p) Under the PISA, Ameren Missouri is permitted to defer and recover 85 % of the depreciation expense and earn a return at the applicable WACC on 85 % of investments in certain property, plant, and equipment placed in service and not included in base rates.

Accumulated PISA deferrals, which also earn a return at the applicable WACC, are added to rate base prospectively and amortized over a period of 20 years following a regulatory rate review.

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

Ameren Missouri will collect the amounts necessary to repay the securitized utility tariff bonds over approximately 15 years beginning in December 2024.

(r) Under-recovered costs associated with Ameren Missouri’s compliance with the state of Missouri’s renewable energy standard.

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These costs are being collected over five years beginning in February 2022.

(t) The electric energy-efficiency investments are being amortized over their weighted-average useful lives beginning in the period in which they were made, with current remaining amortization periods ranging from three to 12 years.

(u) A regulatory recovery mechanism for the difference between actual property taxes incurred by Ameren Missouri and the related taxes included in customer rates.

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The amortization period for amounts accumulated after 2022 will be determined in a future regulatory rate review.

(v) Estimated funds collected from customers to pay for the future removal cost of property, plant, and equipment when retired from service, net of salvage.

(w) The ARO regulatory liability includes the nuclear decommissioning trust fund balance ($ 1,150 million and $ 958 million at December 31, 2023 and 2022, respectively), net of recoverable removal costs for AROs ($ 626 million and $ 593 million at December 31, 2023 and 2022, respectively).

(v) Over-recovered costs from utility customers.

Amounts will be refunded to customers within one year of the deferral.

(w) Estimated funds collected from customers to pay for the future removal cost of property, plant, and equipment when retired from service, net of salvage.

(x) The ARO regulatory liability includes the nuclear decommissioning trust fund balance ($ 1,342 million and $ 1,150 million at December 31, 2024 and 2023, respectively), net of recoverable removal costs for AROs ($ 651 million and $ 626 million at December 31, 2024 and 2023, respectively).

See Note 1 – Summary of Significant Accounting Policies – Asset Retirement Obligations and Removal Costs.

(x) Over-recovered costs are being amortized in proportion to the recognition of prior service costs (credits) and actuarial losses (gains) attributable to Ameren’s pension plan and postretirement benefit plans.

(y) Over-recovered costs are being amortized in proportion to the recognition of prior service costs (credits) and actuarial losses (gains) attributable to Ameren’s pension plan and postretirement benefit plans.

See Note 10 – Retirement Benefits for additional information.

(y) A regulatory recovery mechanism for the difference between the level of pension and postretirement benefit costs incurred by Ameren Missouri and the level of such costs included in customer rates.

(z) A regulatory recovery mechanism for the difference between the level of pension and postretirement benefit costs incurred by Ameren Missouri and the level of such costs included in customer rates.

The period of refund varies based on MoPSC approval in a regulatory rate review.

For electric and natural gas related costs incurred prior to 2023 and 2022, respectively, the weighted-average remaining amortization period is three years .

For electric and natural gas related costs incurred prior to 2023 and 2022, respectively, the weighted-average remaining amortization period is two years .

For electric and natural gas related costs incurred after 2023 and 2022, respectively, the amortization period will be determined in a future regulatory rate review.

(z) Funds collected for the purchase of renewable energy credits and zero emission credits through IPA procurements.

(aa) Funds collected for the purchase of renewable energy credits and zero emission credits through IPA procurements.

The balance will be amortized as the credits are purchased.

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 a reconciliation proceeding, the first of which was initiated in August 2023.

Based on amounts collected from customers and renewable energy credit purchases under contract, the August 2023 reconciliation proceeding did not result in refunds to customers.

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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 latest of which was approved by the ICC in January 2025 and did not result in refunds to customers.

(ab) Funds collected from the issuance of securitized utility tariff bonds by AMF primarily to pay for the decommissioning of the Rush Island Energy Center.

The amortization period for the difference between the estimated costs and the actual costs incurred will be determined in a future regulatory rate review.

NOTE 3 – PROPERTY, PLANT, AND EQUIPMENT, NET

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Other 991 619 131 1,741

Plant to be abandoned, net (e)

Property, plant, and equipment, net $ 18,788 $ 15,530 $ 1,986 $ 36,304

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and 2 to 55 years for other.

(b) Includes $ 29 million of oil-fired generation at December 31, 2023 and 2022.

(b) Includes $ 30 million and $ 29 million of oil-fired generation at December 31, 2024 and 2023, respectively.

(d) Other property, plant, and equipment includes assets used to support electric and natural gas services.

(e) Represents the net book value of the Rush Island Energy Center as Ameren Missouri expects to retire the energy center significantly in advance of its previously expected useful life and in the near term.

See Plant to be Abandoned, Net under Note 1 – Summary of Significant Accounting Policies, NSR and Clean Air Act Litigation under Note 14 – Commitments and Contingencies, and Securitization of the Rush Island Energy Center under Note 2 – Rate and Regulatory Matters for additional information on the planned accelerated retirement of the Rush Island Energy Center.

(f) Original cost amounts include two CTs that had related financing obligations.

The financing obligation for the Peno Creek CT Energy Center was settled in December 2022, while the financing obligation for the Audrain CT Energy Center was settled in January 2023.

The gross cumulative plant asset values related to outstanding financing obligations as of December 31, 2022 was $ 125 million and the related accumulated depreciation was $ 54 million.

See Note 5 – Long-term Debt and Equity Financings for additional information on these agreements.

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(e) Represents the net book value of the Rush Island Energy Center as Ameren Missouri retired the energy center in October 2024, significantly in advance of its previously expected useful life.

See Plant to be Abandoned, Net under Note 1 – Summary of Significant Accounting Policies, NSR and Clean Air Act Litigation under Note 14 – Commitments and Contingencies, and Securitization of Rush Island Energy Center Costs under Note 2 – Rate and Regulatory Matters for additional information on the accelerated retirement of the Rush Island Energy Center.

Capitalized software costs are classified within “Property, Plant, and Equipment, Net” on the balance sheet and are amortized on a straight-line basis over the expected period of benefit, ranging from 2 to 15 years, with the amortization expense included in “Depreciation and amortization” on the statement of income.

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NOTE 4 – SHORT-TERM DEBT AND LIQUIDITY

The liquidity needs of the Ameren Companies are typically supported through the use of available cash, drawings under committed credit agreements, commercial paper issuances, and/or, in the case of Ameren Missouri and Ameren Illinois, short-term affiliate borrowings.

The liquidity needs of the Ameren Companies are supported through the use of available cash, drawings under committed credit agreements, commercial paper issuances, and/or, in the case of Ameren Missouri and Ameren Illinois, short-term affiliate borrowings.

Short-Term Borrowings

In December 2024, the Credit Agreements, which were scheduled to mature in December 2027, were extended and now mature in December 2028.

The Credit Agreements provide $ 2.6 billion of credit cumulatively through maturity in December 2028.

The total facility size of the Missouri Credit Agreement and Illinois Credit Agreement is $ 1.4 billion and $ 1.2 billion, respectively.

The maturity date of each Credit Agreement may be extended for two additional one-year periods upon the mutual consent of the respective borrowers and the lenders.

The maturity date of each Credit Agreement may be extended for an additional one-year period upon the mutual consent of the respective borrowers and the lenders.

Credit available under the agreements is provided by 20 international, national, and regional lenders, with no single lender providing more than $ 156 million of credit in aggregate.

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Loans are available on a revolving basis under each of the Credit Agreements.

Funds borrowed may be repaid and, subject to satisfaction of the conditions to borrowing, reborrowed from time to time.

At the election of each borrower, the interest rates on such loans will be the alternate base rate plus the margin applicable to the

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particular borrower and/or the eurodollar rate plus the margin applicable to the particular borrower.

Funds borrowed may be repaid and, subject to satisfaction of the conditions to borrowing, reborrowed from time to

At the election of each borrower, the interest rates on such loans will be the alternate base rate plus the margin applicable to the particular borrower and/or the eurodollar rate plus the margin applicable to the particular borrower.

The applicable margins will be determined by the borrower’s long-term unsecured credit ratings or, if no such ratings are in effect, the borrower’s corporate/issuer ratings then in effect.

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In addition, the issuance of letters of credit is subject to the $ 2.6 billion overall combined facility borrowing limitations of the Credit Agreements.

The borrowers will use the proceeds from any borrowings under the Credit Agreements for general corporate purposes, including working capital, commercial paper liquidity support, loan funding under the Ameren money pool arrangements, and other short-term affiliate loan arrangements.

The borrowers will use the proceeds from any borrowings under the Credit Agreements for general corporate purposes, including working capital, loan funding under the Ameren money pool arrangements, and other short-term affiliate loan arrangements.

The Missouri Credit Agreement and the Illinois Credit Agreement are available to support issuances under Ameren (parent)’s, Ameren Missouri’s and Ameren Illinois’ commercial paper programs, respectively, subject to borrowing sublimits, as well as to support issuance of letters of credit for the borrowers.

As of December 31, 2024, based on credit capacity available under the Credit Agreements, along with cash and cash equivalents, the net liquidity available to Ameren (parent), Ameren Missouri, and Ameren Illinois, collectively, was $ 1.4 billion.

The following table summarizes the activity and relevant interest rates for Ameren (parent)’s, Ameren Missouri’s, and Ameren Illinois’ commercial paper issuances and borrowings under the Credit Agreements in the aggregate for the years ended December 31, 2023 and 2022:

The following table summarizes the activity and relevant interest rates for Ameren (parent)’s, Ameren Missouri’s, and Ameren Illinois’ commercial paper issuances under the Credit Agreements in the aggregate for the years ended December 31, 2024 and 2023:

Ameren (parent) Ameren Missouri Ameren Illinois Ameren Consolidated

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However, a default of Ameren Missouri or Ameren Illinois under the applicable credit agreement is also deemed to constitute a default of Ameren (parent) under such agreement.

Defaults include a cross-default resulting from a default of such borrower under any other agreement covering outstanding indebtedness of such borrower and certain subsidiaries (other than project finance subsidiaries and nonmaterial subsidiaries) in excess of $ 100 million in the aggregate (including under the other credit agreement).

However, under the default provisions of the Credit Agreements, any default of Ameren (parent) under either credit agreement that results solely from a default of Ameren Missouri or Ameren Illinois does not result in a

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cross-default of Ameren (parent) under the other credit agreement.

Defaults include a cross-default resulting from a default of such borrower under any other agreement covering outstanding indebtedness of such borrower and certain subsidiaries (other than project finance subsidiaries, nonmaterial subsidiaries, and certain special purposes entities contemplated in the Credit Agreements) in excess of $ 100 million in the aggregate (including under the other credit agreement).

Further, the Credit Agreements default provisions provide that an Ameren (parent) default under either of the Credit Agreements does not constitute a default by Ameren Missouri or Ameren Illinois.

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See Note 13 – Related-party Transactions for the amount of interest income and expense from the utility money pool agreement recorded by Ameren Missouri and Ameren Illinois for the years ended December 31, 2024, 2023, and 2022.

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NOTE 5 – LONG-TERM DEBT AND EQUITY FINANCINGS

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2.75 % 1998 Series C bonds due 2033 (c)

5.20 % First mortgage bonds due 2034 (b)

5.50 % Senior secured notes due 2034 (a)

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8.45 % Senior secured notes due 2039 (a)(d)

4.85 % Securitized utility tariff bonds due 2039 (e)

3.90 % Senior secured notes due 2042 (a)(d)

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5.45 % First mortgage bonds due 2053 (b)

Finance obligations:

Audrain County agreement (Audrain County CT) due 2023 (e)

5.25 % First mortgage bonds due 2054 (b)

5.125 % First mortgage bonds due 2055 (b)

Total long-term debt, gross 7,825 6,399

Long-term debt – related parties, gross

Unamortized discount and premium ( 17 ) ( 13 )

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Long-term debt, net $ 7,671 $ 5,991

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Ameren Illinois:

Bonds and notes:

0.375 % First mortgage bonds due 2023 (f)

3.25 % Senior secured notes due 2025 (g)

6.125 % Senior secured notes due 2028 (g)

3.80 % First mortgage bonds due 2028 (f)

1.55 % First mortgage bonds due 2030 (f)

3.85 % First mortgage bonds due 2032 (f)

4.95 % First mortgage bonds due 2033 (f)

6.70 % Senior secured notes due 2036 (g)

4.80 % Senior secured notes due 2043 (g)

4.30 % Senior secured notes due 2044 (g)

4.15 % Senior secured notes due 2046 (g)

3.70 % First mortgage bonds due 2047 (f)

4.50 % First mortgage bonds due 2049 (f)

3.25 % First mortgage bonds due 2050 (f)

2.90 % First mortgage bonds due 2051 (f)

5.90 % First mortgage bonds due 2052 (f)

3.25 % Senior secured notes due 2025 (f)

6.125 % Senior secured notes due 2028 (f)

3.80 % First mortgage bonds due 2028 (g)

1.55 % First mortgage bonds due 2030 (g)

3.85 % First mortgage bonds due 2032 (g)

4.95 % First mortgage bonds due 2033 (g)

6.70 % Senior secured notes due 2036 (f)

4.80 % Senior secured notes due 2043 (f)

4.30 % Senior secured notes due 2044 (f)

4.15 % Senior secured notes due 2046 (f)

3.70 % First mortgage bonds due 2047 (g)

4.50 % First mortgage bonds due 2049 (g)

3.25 % First mortgage bonds due 2050 (g)

2.90 % First mortgage bonds due 2051 (g)

5.90 % First mortgage bonds due 2052 (g)

5.55 % First mortgage bonds due 2054 (g)

Total long-term debt, gross 5,913 5,288

Long-term debt – related parties, gross

Unamortized discount and premium ( 10 ) ( 9 )

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2.45 % Senior unsecured notes due 2036 (h)

5.17 % Senior unsecured notes due 2039

3.43 % Senior unsecured notes due 2050 (i)

2.96 % Senior unsecured notes due 2052 (j)

5.42 % Senior unsecured notes due 2053

Total long-term debt, gross 661 570

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Redemption, purchase, or maturity of all first mortgage bonds, including first mortgage bonds currently outstanding and any that may be issued in the future, would result in a release of the first mortgage bonds currently securing these notes, at which time these notes would become unsecured obligations.

Considering the 2053 maturity of the 5.45 % first mortgage bonds and the restrictions preventing a release date to occur that are attached to certain senior secured notes described in footnote (d) below, Ameren Missouri does not expect the first mortgage lien protection associated with these notes to fall away.

(b) These bonds are first mortgage bonds issued by Ameren Missouri under the Ameren Missouri bond indenture.

Considering the 2055 maturity date of the 5.125 % first mortgage bonds and the restrictions preventing a release date to occur that are attached to certain senior secured notes described in footnote (d) below, Ameren Missouri does not expect the first mortgage lien protection associated with these notes to fall away.

(b) These bonds are first mortgage bonds issued by Ameren Missouri under the Ameren Missouri mortgage indenture.

They are secured by substantially all Ameren Missouri property and franchises.

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(d) Ameren Missouri has agreed that so long as any of the 3.90 % senior secured notes due 2042 are outstanding, Ameren Missouri will not permit a release date to occur, and so long as any of the 8.45 % senior secured notes due 2039 are outstanding, Ameren Missouri will not optionally redeem, purchase, or otherwise retire in full the outstanding first mortgage bonds not subject to release provisions.

(e) No cash was exchanged associated with the termination of the Audrain County agreement as the $ 240 million principal amount of the financing obligation due from Ameren Missouri was equal to the amount of bond service payments due to Ameren Missouri.

The balance of the financing obligation and the related investment in debt securities was $ 240 million as of December 31, 2022.

The investment was recorded in “Investments in industrial development revenue bonds” as of December 31, 2022.

See below for additional information on this financing obligation.

(f) These bonds are first mortgage bonds issued by Ameren Illinois under the Ameren Illinois mortgage indenture.

They are secured by substantially all Ameren Illinois property and franchises.

(g) These notes are collaterally secured by first mortgage bonds issued by Ameren Illinois under the Ameren Illinois mortgage indenture.

The notes have a fall-away lien provision and will remain secured only as long as any first mortgage bonds issued under its mortgage indenture remain outstanding.

(e) These bonds were issued by AMF.

The bondholders of AMF have no recourse to Ameren Missouri’s assets.

Ameren Missouri collects securitization surcharges to cover the principal and interest on the bonds as well as certain other qualified costs.

The surcharges collected by Ameren Missouri on behalf of AMF are remitted to AMF and are not available to creditors of Ameren Missouri.

Principal and interest payments on these bonds are payable semiannually on April 1 and October 1 of each year, beginning October 1, 2025, with final principal and interest payment due October 1, 2039.

(f) These notes are collaterally secured by first mortgage bonds issued by Ameren Illinois under the Ameren Illinois mortgage indenture.

The notes have a fall-away lien provision and will remain secured only as long as any first mortgage bonds issued under the Ameren Illinois mortgage indenture remain outstanding.

Considering the 2054 maturity date of the 5.55 % first mortgage bonds, Ameren Illinois does not expect the first mortgage lien protection associated with these notes to fall away.

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(g) These bonds are first mortgage bonds issued by Ameren Illinois under the Ameren Illinois mortgage indenture.

They are secured by substantially all Ameren Illinois property and franchises.

(h) The following table presents the principal maturities schedule for the 2.45 % senior unsecured notes due 2036:

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August 2050 76

(j) The following table presents the principal maturities schedule for the 2.96 % senior unsecured notes due 2052:

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(a) Excludes unamortized discount, premium, and debt issuance costs of $ 17 million, $ 79 million, $ 61 million, and $ 2 million at Ameren (parent), Ameren Missouri, Ameren Illinois, and ATXI, respectively.

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In November and December 2024, Ameren (parent) purchased senior secured notes and first mortgage bonds issued by Ameren Missouri and first mortgage bonds issued by Ameren Illinois for $ 44 million in the aggregate.

On a consolidated basis, Ameren (parent)’s repurchase of these senior secured notes and first mortgage bonds were accounted for as a debt extinguishment and resulted in a pre-tax gain of $ 16 million, which is reflected in “Other Income, Net” on Ameren’s consolidated statement of income.

Interest expense related to the repurchased bonds was less than $ 1 million for the year ended December 31, 2024.

The following table presents Ameren Missouri’s and Ameren Illinois’ “Long-term Debt, Net - Related Parties” as of December 31, 2024 and 2023:

Ameren Missouri:

3.65 % Senior secured notes due 2045

3.25 % First mortgage bonds due 2049

2.625 % First mortgage bonds due 2051

3.90 % First mortgage bonds due 2052

Total long-term debt - related parties, gross 58 —

Unamortized debt issuance costs ( 1 ) —

Long-term debt - related parties, net $ 57 $ —

Ameren Illinois:

3.70 % First mortgage bonds due 2047

3.25 % First mortgage bonds due 2050

Long-term debt - related parties, net $ 3 $ —

All classes of Ameren Missouri’s and Ameren Illinois’ preferred stock are entitled to cumulative dividends, have voting rights, and are not subject to mandatory redemption.

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Shares of common stock issuable under the 401(k) plan are, at Ameren’s option, newly issued shares, treasury shares, or shares purchased in the open market or in privately negotiated contracts.

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Ameren has entered into an equity distribution sales agreement pursuant to which Ameren may offer and sell from time to time up to $ 1.75 billion of its common stock through an ATM program, which includes the ability to enter into forward sale agreements.

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As of December 31, 2024, Ameren had approximately $ 550 million of common stock available for sale under the ATM program, which takes into account the forward sale agreements in effect as of December 31, 2024 discussed below.

The forward sale agreements outstanding as of December 31, 2023, can be settled at Ameren’s discretion on or prior to dates ranging from October 3, 2024 to February 28, 2025.

The forward sale agreements outstanding as of December 31, 2024, can be settled at Ameren’s discretion on or prior to dates ranging from January 23, 2026 to March 6, 2026.

On a settlement date or dates, if Ameren elects to physically settle a forward sale agreement, Ameren will issue shares of common stock to the counterparties at the then-applicable forward sale price.

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Each forward sale price is subject to adjustment based on a floating interest rate factor equal to the overnight bank funding rate less a spread of 75 basis points, and will be subject to decrease on certain dates specified in the forward sale agreements by specified amounts related to expected dividends on shares of the common stock during the term of the forward sale agreements.

If the overnight bank funding rate is less than the spread on any day, the interest rate factor will result in a reduction of the forward sale price.

If the overnight bank funding rate is less than or more than the spread on any day, the interest rate factor will result in a reduction or an increase, respectively, of the forward sale price.

The forward sale agreements will be physically settled unless Ameren elects to settle in cash or to net share settle.

At December 31, 2024, Ameren could have settled the forward sale agreements with physical delivery of 2.5 million shares of common stock to the respective counterparties in exchange for cash of $ 213 million.

Alternatively, the forward sale agreements could have also been settled at December 31, 2023, with the counterparties delivering approximately $ 24 million of cash or approximately 0.3 million shares of common stock to Ameren.

Alternatively, the forward sale agreements could have also been settled at December 31, 2024, with delivery of approximately $ 13 million of cash or approximately 0.1 million shares of common stock to the counterparties.

In connection to the forward sale agreements, the various counterparties, or their affiliates, borrowed from third parties and sold 2.5 million shares of common stock.

The gross sales price of these shares totaled $ 215 million.

Ameren has not received any proceeds from such sales of borrowed shares.

Ameren does not receive any proceeds from such sales of borrowed shares.

The forward sale agreements have been classified as equity transactions.

In February 2021, Ameren settled the remainder of a forward sale agreement entered into in August 2019, by physically delivering 1.6 million shares of common stock for cash proceeds of $ 113 million.

The proceeds were used to fund a portion of Ameren Missouri’s wind generation investments.

In January 2025, Ameren entered into a forward sale agreement under the ATM program related to 0.6 million shares of common stock.

The January 2025 forward sale agreement can be settled at Ameren’s discretion on or prior to February 9, 2026.

The forward sale price was initially $ 87.43 for the January 2025 forward sale agreement.

In September 2024, $ 450 million principal amount of Ameren (parent)’s 2.50 % senior unsecured notes matured and was repaid with commercial paper borrowings.

In November 2023, Ameren (parent) issued $ 600 million of 5.70 % senior unsecured notes due December 2026, with interest payable semiannually on June 1 and December 1 of each year, beginning June 1, 2024.

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Net proceeds from this issuance were used for capital expenditures and to repay short-term debt.

In April 2024, Ameren Missouri issued $ 500 million of 5.20 % first mortgage bonds due April 2034, with interest payable semiannually on April 1 and October 1 of each year, beginning October 1, 2024.

Net proceeds from this issuance were used for capital expenditures and to repay short-term debt.

In April 2024, $ 350 million principal amount of Ameren Missouri’s 3.50 % senior secured notes matured and was repaid with cash on hand.

In October 2024, Ameren Missouri issued $ 450 million of 5.125 % first mortgage bonds due March 2055, with interest payable semiannually on March 15 and September 15 of each year, beginning March 15, 2025.

Net proceeds from this issuance were used for capital expenditures and to repay short-term debt.

In December 2024, AMF issued $ 476 million of 4.85 % securitized utility tariff bonds due October 2039, with principal and interest payable semiannually on April 1 and October 1 of each year, beginning October 1, 2025.

Net proceeds from this issuance were used 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, and to repay short-term debt.

See Note 2 – Rate and Regulatory Matters for additional information on the securitization of Rush Island Energy Center costs.

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

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Net proceeds from this issuance were used for capital expenditures and to repay short-term debt.

In April 2022, Ameren Missouri issued $ 525 million of 3.90 % green first mortgage bonds due April 2052, with interest payable semiannually on April 1 and October 1 of each year, beginning October 1, 2022.

Net proceeds from this issuance were used for capital expenditures and to repay short-term debt.

Ameren Missouri intends to allocate an amount equal to the net proceeds to sustainability projects meeting certain eligibility criteria.

In November 2022, $ 47 million principal amount of Ameren Missouri’s 1.60 % 1992 Series bonds matured and were repaid with commercial paper borrowings.

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In December 2022, Ameren Missouri repaid $ 8 million of the remaining principal amount of the financing obligation related to the Peno Creek CT Energy Center to a trustee, which is authorized to utilize the cash only to pay equal amounts due to Ameren Missouri under related bonds issued by the city of Bowling Green and held by Ameren Missouri.

The timing and amounts of payments due from Ameren Missouri under the agreement were equal to the timing and amount of bond service payments due to Ameren Missouri, resulting in no net cash flow.

Under the terms of this agreement, Ameren Missouri was responsible for all operation and maintenance for the energy center.

Ownership of the energy center transferred to Ameren Missouri in December 2022, at which time the property, plant, and equipment became subject to the lien of the Ameren Missouri mortgage bond indenture.

For information on Ameren Missouri’s capital contributions, refer to Capital Contributions in Note 13 – Related-party Transactions.

Ameren Illinois

In June 2024, Ameren Illinois issued $ 625 million of 5.55 % first mortgage bonds due July 2054, with interest payable semiannually on January 1 and July 1 of each year, beginning January 1, 2025.

Net proceeds from this issuance were used to repay short-term debt.

In May 2023, Ameren Illinois issued $ 500 million of 4.95 % first mortgage bonds due June 2033, with interest payable semiannually on June 1 and December 1 of each year, beginning December 1, 2023.

Net proceeds from this issuance were used to repay $ 100 million principal amount of its 0.375 % first mortgage bonds that matured in June 2023 and short-term debt.

In August 2022, Ameren Illinois issued $ 500 million of 3.85 % first mortgage bonds due September 2032, with interest payable semiannually on March 1 and September 1 of each year, beginning March 1, 2023.

Net proceeds from this issuance were used to repay $ 400 million principal amount of its 2.70 % senior secured notes that matured in September 2022 and short-term debt.

In November 2022, Ameren Illinois issued $ 350 million of 5.90 % first mortgage bonds due December 2052, with interest payable semiannually on June 1 and December 1 of each year, beginning June 1, 2023.

Net proceeds from this issuance were used to repay short-term debt.

Ameren Illinois intends to allocate an amount equal to the net proceeds to sustainability projects meeting certain eligibility criteria.

For information on Ameren Illinois’ capital contributions, refer to Capital Contributions in Note 13 – Related-party Transactions.

In August 2022, ATXI issued $ 95 million of its 2.96 % senior unsecured notes due 2052 pursuant to a November 2021 note purchase agreement, with interest payable semiannually on February 25 and August 25 of each year, beginning February 25, 2023, through a private placement offering exempt from registration under the Securities Act of 1933, as amended.

Net proceeds from this issuance were used to refinance the remaining portion of an intercompany long-term note with Ameren (parent), repay a $ 50 million principal payment of its 3.43 % senior unsecured notes in August 2022, and to repay short-term debt.

In August 2024, ATXI issued $ 70 million of 5.17 % senior unsecured notes due September 2039 and $ 70 million of 5.42 % senior unsecured notes due September 2053, pursuant to an August 2024 note purchase agreement.

Both series of senior unsecured notes have interest payable semiannually on March 1 and September 1 of each year, beginning March 1, 2025, and were issued through a private placement offering exempt from registration under the Securities Act of 1933, as amended.

Net proceeds from these issuances were used to repay a $ 49 million principal payment of ATXI’s 3.43 % senior unsecured notes at maturity and to repay short-term debt.

Indenture Provisions and Other Covenants

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Specifically, either (1) the failure by Ameren to pay when due and upon expiration of any applicable grace period any portion of any Ameren indebtedness in excess of $ 25 million, or (2) the acceleration upon default of the maturity of any Ameren indebtedness in excess of $ 25 million under any indebtedness agreement, including borrowings under the Credit Agreements or the Ameren commercial paper program, constitutes a default under the indenture, unless such past due or accelerated debt is discharged or the acceleration is rescinded or annulled within a specified period.

Table of Conten t s

Ameren Missouri and Ameren Illinois and certain other nonregistrant Ameren subsidiaries are subject to Section 305(a) of the Federal Power Act, which makes it unlawful for any officer or director of a public utility, as defined in the Federal Power Act, to participate in the making or paying of any dividend from any funds “properly included in capital account.” The FERC has consistently interpreted the provision to allow dividends to be paid as long as (1) the source of the dividends is clearly disclosed, (2) the dividends are not excessive, and (3) there is no self-dealing on the part of corporate officials.

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Off-Balance-Sheet Arrangements

At December 31, 2023, none of the Ameren Companies had any material off-balance-sheet financing arrangements, other than their investments in variable interest entities and the multiple forward sale agreements under the ATM program relating to common stock.

At December 31, 2024, none of the Ameren Companies had any material off-balance-sheet financing arrangements, other than their investments in variable interest entities, letters of credit, and the multiple forward sale agreements under the ATM program relating to common stock.

See Note 1 – Summary of Significant Accounting Policies for further detail concerning variable interest entities.

Table of Conten t s

NOTE 6 – OTHER INCOME, NET

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Miscellaneous income 9 7 10

Earnings related to equity method investments 1 2 12

Gain on extinguishment of debt (b)

Earnings (losses) related to equity method investments ( 4 ) 1 2

Donations ( 5 ) ( 24 ) ( 26 )

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Allowance for equity funds used during construction $ 17 $ 19 $ 18

Interest income 21 7 1

Other Interest income 32 21 7

Non-service cost components of net periodic benefit income 105 124 84

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(a) For the years ended December 31, 2024, 2023, and 2022, the non-service cost components of net periodic benefit income were adjusted by amounts deferred of $( 41 ) million, $ 27 million, and $ 22 million, respectively, due to a regulatory tracking mechanism for the difference between the level of such costs incurred by Ameren Missouri under GAAP and the level of such costs included in rates.

See Note 10 – Retirement Benefits for additional information.

(b) See Note 5 – Long-term Debt and Equity Financings for additional information on Ameren (parent)’s repurchase of Ameren Missouri’s senior secured notes and first mortgage bonds and Ameren Illinois’ first mortgage bonds that were accounted for as a debt extinguishment.

NOTE 7 – DERIVATIVE FINANCIAL INSTRUMENTS

We use derivatives to manage the risk of changes in market prices for natural gas, power, and uranium, as well as the risk of changes in rail transportation surcharges through fuel oil hedges.

We use derivatives to manage the risk of changes in market prices for natural gas, power, uranium, and interest rates, as well as the risk of changes in rail transportation surcharges through fuel oil hedges.

Such price fluctuations may cause the following:

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• market values of natural gas and uranium inventories that differ from the cost of those commodities in inventory;

• actual cash outlays for the purchase of these commodities that differ from anticipated cash outlays;

• actual cash outlays for interest expense and the purchase of commodities that differ from anticipated cash outlays;

• actual off-system sales revenues that differ from anticipated revenues.

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Contracts we enter into as part of our risk management program may be settled financially, settled by physical delivery, or net settled with the counterparty.

Table of Conten t s

All contracts considered to be derivative instruments are required to be recorded on the balance sheet at their fair values, unless the NPNS exception applies.

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Therefore, gains and losses on these derivatives have no effect on operating income.

As of December 31, 2023 and 2022, all contracts that met the definition of a derivative and were not eligible for the NPNS exception received regulatory deferral.

As of December 31, 2024 and 2023, all commodity contracts that met the definition of a derivative and were not eligible for the NPNS exception received regulatory deferral.

Interest rate hedges discussed below do not receive regulatory deferral and were included in accumulated OCI.

The cash flows from our derivative financial instruments follow the cash flow classification of the hedged item.

In 2024, Ameren (parent) entered into interest rate swaps to hedge a portion of our interest rate risk on cash flows related to forecasted debt issuances through 2026.

The interest rate swaps are designated as cash flow hedges and the corresponding changes in fair value each period are initially recorded on the balance sheet in “Accumulated other comprehensive loss” and reclassified into earnings when the debt is issued and the corresponding interest payments affect earnings during the debt term.

At December 31, 2024, Ameren had interest rate swaps with notional amounts of $ 140 million.

The changes in fair value of the interest rate swaps were immaterial at December 31, 2024 .

The following table presents open gross commodity contract volumes by commodity type for derivative assets and liabilities as of December 31, 2024 and 2023.

As of December 31, 2023, these contracts extended through October 2026, October 2029, May 2032, and March 2024 for fuel oils, natural gas, power, and uranium, respectively.

As of December 31, 2024, these contracts extended through October 2028, October 2029, and May 2032 for fuel oils, natural gas, and power, respectively.

Quantity (in millions, except as indicated)

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Total liabilities $ 15 $ 88 $ 103 $ 25 $ 143 $ 168

We believe that entering into master netting arrangements or similar agreements mitigates the level of financial loss that could result from default by allowing net settlement of derivative assets and liabilities.

These master netting arrangements allow the counterparties to net settle sale and purchase transactions.

Further, collateral requirements are calculated at the master netting arrangement or similar agreement level by counterparty.

Table of Conten t s

The following table provides the recognized gross derivative balances and the net amounts of those derivatives subject to an enforceable master netting arrangement or similar agreement as of December 31, 2023 and 2022:

Gross Amounts Not Offset in the Balance Sheet

Commodity Contracts Eligible to be Offset Gross Amounts Recognized in the Balance Sheet Derivative Instruments Cash Collateral Received/Posted (a)

Ameren Missouri $ 19 $ 6 $ — $ 13

Ameren Illinois 3 1 — 2

Ameren $ 22 $ 7 $ — $ 15

Ameren Missouri $ 25 $ 6 $ — $ 19

Ameren Illinois 143 1 6 136

Ameren $ 168 $ 7 $ 6 $ 155

Ameren Missouri $ 49 $ 9 $ — $ 40

Ameren Illinois 40 20 — 20

Ameren $ 89 $ 29 $ — $ 60

Ameren Missouri $ 68 $ 9 $ 56 $ 3

Ameren Illinois 68 20 — 48

Ameren $ 136 $ 29 $ 56 $ 51

(a) Cash collateral received reduces gross asset balances and is included in “Other current liabilities” and “Other deferred credits and liabilities” on the balance sheet.

Cash collateral posted reduces gross liability balances and is included in “Current collateral assets” and “Other assets” on the balance sheet for Ameren and Ameren Missouri and “Other current assets” and “Other assets” for Ameren Illinois.

The Ameren Companies elect to present the fair value amounts of derivative assets and derivative liabilities subject to an enforceable master netting arrangement or similar agreement at the gross amounts on the balance sheet.

However, if the gross amounts recognized on the balance sheet were netted with derivative instruments and cash collateral received or posted, the net amounts would not be materially different from the gross amounts at December 31, 2024 and 2023.

In determining our concentrations of credit risk related to derivative instruments, we review our individual counterparties and categorize each counterparty into groupings according to the primary business in which each engages.

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The additional collateral required is the net liability position allowed under the master netting arrangements or similar agreements, assuming (1) the credit risk-related contingent features underlying these arrangements were triggered and (2) those counterparties with rights to do so requested collateral.

The following table presents, as of December 31, 2023, the aggregate fair value of all derivative instruments with credit risk-related contingent features in a gross liability position, the cash collateral posted, and the aggregate amount of additional collateral that counterparties could require:

Aggregate Fair Value of

Derivative Liabilities (a)

Collateral Posted Potential Aggregate Amount of

Additional Collateral Required (b)

Ameren Missouri $ 24 $ — $ 19

Ameren Illinois 74 6 66

Ameren $ 98 $ 6 $ 85

(a) Before consideration of master netting arrangements or similar agreements.

(b) As collateral requirements with certain counterparties are based on master netting arrangements or similar agreements, the aggregate amount of additional collateral required to be posted is determined after consideration of the effects of such arrangements.

Table of Conten t s

As of December 31, 2024, the aggregate fair value of derivative instruments with credit risk-related contingent features in a gross liability position, the cash collateral posted, and the aggregate amount of additional collateral that counterparties could require were each immaterial to Ameren, Ameren Missouri, and Ameren Illinois.

NOTE 8 – FAIR VALUE MEASUREMENTS

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At December 31, 2024 and 2023, the counterparty default risk valuation adjustment related to derivative contracts was immaterial for Ameren, Ameren Missouri, and Ameren Illinois.

Table of Conten t s

The following table sets forth, by level within the fair value hierarchy, our assets and liabilities measured at fair value on a recurring basis as of December 31, 2024 and 2023:

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Natural gas $ — $ 3 $ 3 $ 6 $ — $ 1 $ 2 $ 3

Power — — — — — — 6 6

Total Ameren Illinois $ — $ 3 $ 3 $ 6 $ — $ 1 $ 2 $ 3

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(a) Balance excludes $ 9 million and $ 9 million of cash and cash equivalents, receivables, payables, and accrued income, net for December 31, 2024 and 2023, respectively.

(b) See the Ameren Missouri and Ameren Illinois sections of the table for a breakout of the fair value of Ameren’s derivative assets and liabilities by type of commodity.

(c) See the Ameren Missouri section of the table for a breakout of Ameren’s nuclear decommissioning trust fund by investment type.

(b) See the Ameren Missouri and Ameren Illinois sections of the table for the fair value of Ameren’s derivative assets and liabilities by type of commodity.

See Note 10 – Retirement Benefits for tables that set forth, by level within the fair value hierarchy, Ameren’s pension and postretirement plan assets as of December 31, 2024 and 2023.

Table of Conten t s

Level 3 fuel oils, natural gas and uranium derivative contract assets and liabilities measured at fair value on a recurring basis were immaterial for all periods presented.

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All gains or losses related to our Level 3 derivative commodity contracts are expected to be recovered or returned through customer rates;

therefore, there is no impact to either net income or other comprehensive income resulting from changes in the fair value of these instruments.

therefore, there is no impact to either net income or OCI resulting from changes in the fair value of these instruments.

The following table describes the valuation techniques and significant unobservable inputs utilized for the fair value of our Level 3 power derivative contract assets and liabilities as of December 31, 2024 and 2023:

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Nodal basis ($/MWh) ( 8 ) – ( 1 )

Trend rate (%) 0 – 1

(a) Generally, significant increases (decreases) in these inputs in isolation would result in a significantly higher (lower) fair value measurement.

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(d) Valuations through 2031 use visible forward prices adjusted for nodal-to-hub basis differentials.

Valuations beyond 2031 use a trend rate factor and are similarly adjusted for nodal-to-hub basis differentials.

Table of Conten t s

The following table sets forth, by level within the fair value hierarchy, the carrying amount and fair value of financial assets and liabilities disclosed, but not carried, at fair value as of December 31, 2023 and 2022:

Amount Fair Value

Level 1 Level 2 Level 3 Total

The following table sets forth the carrying amount and, by level within the fair value hierarchy, the fair value of long-term debt (including current portion), disclosed, but not recorded, at at fair value as of December 31, 2024 and 2023:

Long-Term Debt (Including Current Portion):

Level 2 Level 3 Total

December 31, 2024

Cash, cash equivalents, and restricted cash $ 272 $ 272 $ — $ — $ 272

Short-term debt 536 — 536 — 536

Long-term debt (including current portion) 15,970 (a)

— 14,366 467 (b)

Ameren Missouri:

Cash, cash equivalents, and restricted cash $ 10 $ 10 $ — $ — $ 10

Short-term debt 170 — 170 — 170

Borrowings from money pool 306 — 306 — 306

Long-term debt (including current portion) 6,341 (a)

17,579 15,395 538 (c)

Ameren Missouri (d)

7,745 6,926 — 6,926

Ameren Illinois:

Cash, cash equivalents, and restricted cash $ 234 $ 234 $ — $ — $ 234

Short-term debt 366 — 366 — 366

Borrowings from money pool 135 — 135 — 135

Long-term debt (including current portion) 5,232 (a)

Ameren Illinois (d)

5,852 5,243 — 5,243

December 31, 2023

Cash, cash equivalents, and restricted cash $ 216 $ 216 $ — $ — $ 216

Investments in industrial development revenue bonds (c)

240 — 240 — 240

Short-term debt 1,070 — 1,070 — 1,070

Long-term debt (including current portion) (c)

— 11,989 464 (b)

Ameren 15,970 14,366 467 (c)

Ameren Missouri 6,341 5,800 — 5,800

Cash, cash equivalents, and restricted cash $ 13 $ 13 $ — $ — $ 13

Investments in industrial development revenue bonds (c)

240 — 240 — 240

Short-term debt 329 — 329 — 329

Long-term debt (including current portion) (c)

— 5,365 — 5,365

Ameren Illinois 5,232 4,867 — 4,867

Cash, cash equivalents, and restricted cash $ 191 $ 191 $ — $ — $ 191

Short-term debt 264 — 264 — 264

Long-term debt (including current portion) 4,835 (a)

— 4,320 — 4,320

(a) Included unamortized debt issuance costs, which were excluded from the fair value measurement, of $ 129 million, $ 62 million, and $ 51 million for Ameren, Ameren Missouri, and Ameren Illinois, respectively, as of December 31, 2024.

Included unamortized debt issuance costs, which were excluded from the fair value measurement, of $ 111 million, $ 45 million, and $ 47 million for Ameren, Ameren Missouri, and Ameren Illinois, respectively, as of December 31, 2023.

(b) The Level 3 fair value amount consists of ATXI’s senior unsecured notes.

(c) Ameren and Ameren Missouri had investments in industrial development revenue bonds, classified as held-to-maturity and recorded in “Investments in industrial development revenue bonds,” as of December 31, 2022, respectively, that were equal to the finance obligation for the Audrain CT energy center.

As of December 31, 2022, the carrying amount of the investments in industrial development revenue bonds and the finance obligations approximated fair value.

The financing obligation for the Audrain CT Energy Center was settled in January 2023.

See Note 5 – Long-term Debt and Equity Financings for additional information on these agreements.

(b) Amount excludes Ameren (parent)’s repurchase of Ameren Missouri’s senior secured notes and first mortgage bonds and Ameren Illinois’ first mortgage bonds in 2024 that were accounted for as a debt extinguishment.

See Note 5 – Long-term Debt and Equity Financings for additional information.

(d) Amount includes Ameren Missouri’s senior secured notes and first mortgage bonds and Ameren Illinois’ first mortgage bonds that were repurchased by Ameren (parent) in 2024.

The Ameren Companies’ carrying amounts of cash, cash equivalents, and restricted cash approximate fair value and are considered Level 1 in the fair value hierarchy.

The Ameren Companies’ short-term borrowings approximate fair value because of the short-term nature of these instruments and are considered Level 2 in the fair value hierarchy.

NOTE 9 – CALLAWAY ENERGY CENTER

Spent Nuclear Fuel

Under the Nuclear Waste Policy Act of 1982, as amended, the DOE is responsible for disposing of spent nuclear fuel from the Callaway Energy Center and other commercial nuclear energy centers.

Under the Nuclear Waste Policy Act of 1982, as amended, the DOE is responsible for disposing of spent nuclear fuel from the Callaway

Energy Center and other commercial nuclear energy centers.

As required by the act, Ameren Missouri and other utilities have entered into standard contracts with the DOE, which stated that the DOE would begin to dispose of spent nuclear fuel by 1998.

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The DOE’s delay in carrying out its obligation to dispose of spent nuclear fuel from the Callaway Energy Center is not expected to adversely affect the continued operations of the energy center.

Table of Conten t s

Decommissioning

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Cash and cash equivalents 10 — — 10

( 1 ) — — ( 1 )

Total $ 625 $ 742 $ 25 $ 1,342

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(a) Represents net receivables and payables relating to pending securities sales, interest, and securities purchases.

Table of Conten t s

The following table presents the costs and fair values of investments in debt securities in Ameren’s and Ameren Missouri’s nuclear decommissioning trust fund according to their contractual maturities at December 31, 2024:

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If a serious nuclear incident were to occur, it could have a material adverse effect on Ameren’s and Ameren Missouri’s results of operations, financial position, or liquidity.

Table of Conten t s

NOTE 10 – RETIREMENT BENEFITS

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These net assets are recorded in “Pension and other postretirement benefits,” “Other current liabilities,” and “Other deferred credits and liabilities” on Ameren’s consolidated balance sheet.

The increase in the overfunded pension and postretirement benefit plans during 2023 was primarily the result of gains on plan assets of the pension and postretirement trusts during 2023 offset by a 30 -basis-point decrease in the pension and other postretirement benefit plan discount rates used to determine the present value of the obligation.

The increase in the overfunded pension and postretirement benefit plans during 2024 was primarily the result of a 45 -basis-point increase in the pension and other postretirement benefit plan discount rates used to determine the present value of the obligation and an increase in the actual return on plan assets of the pension and postretirement trusts.

The overfunded pension and other postretirement benefit plans also resulted in regulatory liabilities on Ameren’s, Ameren Missouri’s, and Ameren Illinois’ balance sheets.

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(a) Liabilities associated with pension and other postretirement benefits are recorded in “Other current liabilities” and “Other deferred credits and liabilities” on Ameren’s, Ameren Missouri’s, and Ameren Illinois’ balance sheets.

Table of Conten t s

Ameren recognizes the overfunded and underfunded status of its pension and postretirement plans as an asset or a liability on its consolidated balance sheet, with offsetting entries to accumulated OCI and regulatory assets or liabilities.

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Fair value of plan assets at end of year 4,182 1,493 4,272 1,393

Funded status – deficiency (surplus) ( 14 ) ( 537 ) 34 ( 411 )

Accrued benefit cost (asset) at December 31 $ ( 14 ) $ ( 537 ) $ 34 $ ( 411 )

Funded status – surplus ( 48 ) ( 686 ) ( 14 ) ( 537 )

Accrued benefit asset at December 31 $ ( 48 ) $ ( 686 ) $ ( 14 ) $ ( 537 )

Amounts recognized in the balance sheet consist of:

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Noncurrent liability (c)

Net liability (asset) recognized $ ( 14 ) $ ( 537 ) $ 34 $ ( 411 )

Net asset recognized $ ( 48 ) $ ( 686 ) $ ( 14 ) $ ( 537 )

Amounts recognized in regulatory assets or liabilities consist of:

Net actuarial gain $ ( 10 ) $ ( 311 ) $ ( 107 ) $ ( 268 )

Net actuarial (gain) loss $ 42 $ ( 379 ) $ ( 10 ) $ ( 311 )

Prior service credit — ( 21 ) — ( 25 )

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Table of Conten t s

The following table presents the assumptions used to determine our benefit obligations at December 31, 2024 and 2023:

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Increase in future compensation 4.00 3.50 (a)

Cash balance pension plan interest crediting rate 5.50 5.00 (b)

Medical cost trend rate (initial) (d)

Medical cost trend rate (ultimate) (d)

(a) As of December 31, 2023, increase in future compensation is 4.00 % in 2024, and 3.50 % thereafter.

As of December 31, 2022, increase in future compensation was 4.50 % for 2023, 4.00 % in 2024, and 3.50 % thereafter.

(b) Cash balance pension plan interest crediting rate was 5.50 % for 2023 and 2024, and 5.00 % thereafter.

(d) Initial and ultimate medical cost trend rate for certain Medicare-eligible participants was 2.50 % at December 31, 2023 and 2022.

(e) Initial medical cost trend rates of 6.93 % and 7.25 % for pre-Medicare plan participants and 6.50 % and 6.75 % for post-Medicare plan participants at December 31, 2023 and 2022, respectively, trend down to the ultimate rate by 2030 , with a 3.00 % upward adjustment to the post-Medicare trend rate in 2025.

4.00 3.50 (a)

Cash balance pension plan interest crediting rate 5.50 5.50 (b) (b)

Medical cost trend rate (initial) (c)

(b) (b) (d) (d)

Medical cost trend rate (ultimate) (c)

(b) (b) 5.00 5.00

(a) As of December 31, 2023, increase in future compensation was 4.00 % in 2024, and 3.50 % thereafter.

(b) Not applicable.

(c) Initial and ultimate medical cost trend rate for certain Medicare-eligible participants was 2.50 % at December 31, 2024 and 2023.

(d) Initial medical cost trend rates of 7.00 % and 6.93 % for pre-Medicare plan participants and 7.00 % and 6.50 % for post-Medicare plan participants at December 31, 2024 and 2023, respectively, trend down to the ultimate rate by 2033 and 2030 , respectively, with a 3.00 % upward adjustment to the post-Medicare trend rate in 2025.

Ameren determines discount rate assumptions by identifying a theoretical settlement portfolio of high-quality corporate bonds sufficient to provide for a plan’s projected benefit payments.

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

Based on its assumptions at December 31, 2023, its investment performance in 2023, and its pension funding policy, Ameren does not expect to make material contributions in 2024 and 2025, and expects to make aggregate contributions of $ 120 million in 2026 through 2028.

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.

Ameren Missouri and Ameren Illinois estimate that their portion of the future funding requirements will be 40 % and 50 %, respectively.

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Ameren will use an expected return on plan assets for its pension and postretirement plan assets of 6.75 % in 2025.

Table of Conten t s

Ameren’s investment committee strives to assemble a portfolio of diversified assets that does not create a significant concentration of risks.

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however, Ameren is still subject to overall market risk.

Ameren’s investment committee developed and implemented a liability hedging investment strategy for its qualified pension plans designed to reduce interest rate risk as part of an objective for its long-term investment strategy.

Ameren’s investment committee developed and implemented a liability hedging investment strategy for its qualified pension plan designed to reduce interest rate risk as part of an objective for its long-term investment strategy.

The plan invests in derivative instruments mainly consisting of interest rate futures intended to extend the duration of the pension plan assets so that the assets are more closely aligned with the duration of the liabilities.

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In addition to the derivative investments included in the liability hedging investment strategy described above, Ameren’s investment committee also allo ws investment managers to use derivatives, such as index futures, foreign exchange futures, and options, in certain situations to increase or to reduce market exposure in an efficient and timely manner.

Table of Conten t s

Fair Value Measurements of Plan Assets

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Real estate — — 233 233 — — 248 248

Private equity — — — — — — 1 1

Total $ 540 $ 1,542 $ 2,247 $ 4,329 $ 718 $ 1,529 $ 2,256 $ 4,503

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(b) Net of receivables related to pending securities sales and payables related to pending securities purchases.

Table of Conten t s

The following table sets forth, by level within the fair value hierarchy discussed in Note 8 – Fair Value Measurements, the postretirement benefit plans’ assets measured at fair value and NAV as of December 31, 2024 and 2023:

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Amortization of (b) :

Prior service credit — — — ( 4 ) ( 4 ) ( 4 )

Prior service cost (credit) — — — ( 4 ) ( 4 ) ( 4 )

Actuarial (gain) loss ( 67 ) ( 115 ) 25 ( 38 ) ( 45 ) ( 19 )

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(a) Service cost, net of capitalization, is reflected in “Operating Expenses - Other operations and maintenance” on Ameren’s statement of income.

(b) Prior service cost is amortized on a straight-line basis over the average future service of active participants benefiting under the plan amendment.

(b) Prior service cost (credit) is amortized on a straight-line basis over the average future service of active participants benefiting under the plan amendment.

Net actuarial gains or losses related to the net benefit obligation subject to amortization are amortized on a straight-line basis over 10 years.

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(a) Does not include the impact of the tracker for the difference between the level of pension and postretirement benefit costs (income) incurred by Ameren Missouri under GAAP and the level of such costs included in customer rates.

Table of Conten t s

The expected pension and postretirement benefit payments from qualified trust and company funds, which reflect expected future service, as of December 31, 2024, are as follows:

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Increase in future compensation (a)

3.50 3.50 3.50 (a)

3.50 3.50 3.50 3.50 3.50 3.50

Cash balance pension plan interest crediting rate (b)

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Medical cost trend rate (initial) (d)

Medical cost trend rate (ultimate) (d)

(a) Increase in future compensation is 4.50 % for 2023, 4.00 % in 2024, and 3.50 % thereafter for the year ended December 31, 2023.

(b) Cash balance pension plan interest crediting rate is 5.50 % for 2023 and 2024, and 5.00 % thereafter for the year ended December 31, 2023.

(a) Increase in future compensation is 4.00 % for 2024 and 3.50 % thereafter for the year ended December 31, 2024, and was 4.50 % for 2023, 4.00 % for 2024, and 3.50 % thereafter for the year ended December 31, 2023.

(b) Cash balance pension plan interest crediting rate is 6.42 % for 2024 and 5.50 % thereafter for the year ended December 31, 2024, and was 5.50 % for 2023 and 2024, and 5.00 % thereafter for the year ended December 31, 2023.

(d) Initial and ultimate medical cost trend rate for certain Medicare-eligible participants is 2.50 % for the year ended December 31, 2023 and 3.00 % for the years ended December 31, 2022 and 2021.

(d) Initial and ultimate medical cost trend rate for certain Medicare-eligible participants is 2.50 % for the years ended December 31, 2024 and 2023, and 3.00 % for the year ended December 31, 2022.

(e) Initial medical cost trend rates of 6.93 % for pre-Medicare plan participants and 6.50 % for post-Medicare plan participants trend down to the ultimate rate by 2030, with a 3.00 % upward adjustment to the post-Medicare trend rate in 2025.

(f) Initial medical cost trend rates of 7.25 % for pre-Medicare plan participants and 6.75 % for post-Medicare plan participants trend down to the ultimate rate by 2030, with a 3.00 % upward adjustment to the post-Medicare trend rate in 2025.

Ameren sponsors a 401(k) plan for eligible employees.

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Ameren used newly issued shares to fulfill its stock-based compensation obligations for 2024, 2023, and 2022, and intends to use newly issued shares to fulfill its stock-based compensation obligations for 2025.

Table of Conten t s

The following table summarizes Ameren’s outstanding performance share unit and restricted stock unit activity for the year ended December 31, 2024:

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Compensation cost is recognized ratably over the requisite service period only for awards for which it is probable that the performance condition will be satisfied.

(c) Outstanding awards include awards that vest on a pro-rata basis due to attainment of retirement eligibility by certain employees, but have not yet been distributed.

(c) Outstanding awards include awards that vest on a pro-rata basis due to attainment of retirement eligibility by employees, but have not yet been distributed.

In these cases, the pro-rata basis awards have not yet been distributed as the entire performance period has not been completed.

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The exact number of shares issued pursuant to a share unit varies from 0 % to 200 % of the target award, depending on actual company performance relative to the specified market conditions.

The fair value of each share unit is based on Ameren’s closing common share price at December 31 of the year prior to the award year and a Monte Carlo simulation.

The fair value of each share unit is based on a Monte Carlo simulation.

The Monte Carlo simulation is used to estimate expected share payout based on Ameren’s TSR for a three-year performance period relative to the designated peer group beginning January 1st of the award year.

The simulation can produce a greater fair value for the share unit than the applicable closing common share price because it includes the weighted payout scenarios in which an increase in the share price has occurred and/or in which the payout is above 100 % due to Ameren’s projected TSR performance.

The simulation can produce a greater or lesser fair value for the share unit than the applicable closing common share price because it includes the weighted payout scenarios in which an increase or decrease in the share price has occurred and/or in which the payout is above 100 % due to Ameren’s projected TSR performance.

The key assumptions used to calculate fair value also include a three-year risk-free rate, Ameren’s common stock volatility, and volatility for the peer group.

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In addition to the market condition performance share units described above, there are an immaterial number of market condition performance share units with different vesting conditions and target payout percentages.

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Performance Share Units – Performance Condition

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As of December 31, 2024, total compensation cost of $ 39 million related to outstanding awards not yet recognized is expected to be recognized over a weighted-average period of 23 months.

For the years ended December 31, 2023, 2022, and 2021, excess tax benefits associated with the settlement of stock-based compensation awards reduced income tax expense by $ 6 million, $ 5 million, and $ 5 million, respectively.

For the years ended December 31, 2024, 2023, and 2022, excess tax benefits (deficiencies) associated with the settlement of stock-based compensation awards reduced (increased) income tax expense by $( 1 ) million, $ 6 million, and $ 5 million, respectively.

NOTE 12 – INCOME TAXES

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The law extends federal production and investment tax credits for projects beginning construction through 2024 and allows for a 10 % adder to the production and investment tax credits for siting projects at existing energy communities as defined in the law, which includes sites previously used for coal-fired generation.

The law also creates clean energy tax credits for projects placed in service after 2024.

The law also creates clean energy tax credits for projects beginning construction after 2024.

The clean energy tax credits will apply to renewable energy production and investments, along with certain nuclear energy production, and will be phased out beginning in 2033, at the earliest.

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The law allows for transferability to an unrelated party for cash of up to 100 % of certain tax credits generated after 2022.

In addition, the new law imposes a 15 % minimum tax on adjusted financial statement income, as defined in the law, for 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.

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

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

Additional regulations, interpretations, amendments, or technical corrections to or in connection with the IRA have been and are expected to be issued by the IRS or United States Department of Treasury, which may impact the timing of when the 15 % minimum tax becomes applicable for Ameren.

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IRS Natural Gas Repairs and Maintenance Guidance

In April 2023, the IRS issued guidance providing a safe harbor method of accounting for the capitalization or deduction of certain expenditures to maintain, repair, replace, or improve natural gas distribution and transmission property.

Ameren adopted this guidance for the 2024 tax year and, as a result, during December 2024, Ameren, Ameren Missouri, and Ameren Illinois recorded increases to their “plant-related” deferred tax liabilities of $ 123 million, $ 12 million, and $ 111 million, respectively.

The following table presents the principal reasons for the difference between the effective income tax rate and the federal statutory corporate income tax rate for the years ended December 31, 2024, 2023, and 2022:

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Amortization of deferred investment tax credit ( 1 ) — —

Production and other tax credits (b)

Renewable and other tax credits (b)

( 24 ) — ( 9 )

State tax 3 7 5

Depreciation differences — — ( 1 )

Effective income tax rate ( 18 ) % 24 % 7 %

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Amortization of deferred investment tax credit ( 1 ) — —

Production and other tax credits (b)

Renewable and other tax credits (b)

( 10 ) — ( 4 )

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Amortization of deferred investment tax credit ( 1 ) — —

Production and other tax credits (b)

Renewable and other tax credits (b)

( 10 ) — ( 4 )

State tax 3 7 5

Stock-based compensation — — ( 1 )

Effective income tax rate ( 2 ) % 26 % 14 %

(a) Reflects the amortization of amounts resulting from the revaluation of deferred income taxes subject to regulatory ratemaking, which are being refunded to customers.

Deferred income taxes are revalued when federal or state income tax rates change, and the offset to the revaluation of deferred income taxes subject to regulatory ratemaking is recorded to a regulatory asset or liability.

(a) Reflects the amortization of a regulatory liability resulting from the revaluation of accumulated deferred income taxes subject to regulatory ratemaking, which are being refunded to customers.

(b) The benefit of the credits associated with Missouri renewable energy standard compliance is refunded to customers through the RESRAM.

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The benefit of the credits associated with the production and investment tax credit tracker will be refunded to customers based on MoPSC approval in a regulatory rate review.

The following table presents the components of income tax expense (benefit) for the years ended December 31, 2024, 2023, and 2022:

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Amortization of deferred investment tax credits ( 4 ) — — ( 4 )

Total income tax expense $ 3 $ 143 $ 11 $ 157

The following table presents the accumulated deferred income tax assets and liabilities recorded as a result of temporary differences and accumulated deferred investment tax credits at December 31, 2023 and 2022:

Total income tax expense (benefit) $ ( 10 ) $ 179 $ 7 $ 176

The following table presents the accumulated deferred income tax assets and liabilities recorded as a result of temporary differences and accumulated deferred production and investment tax credits at December 31, 2024 and 2023:

Ameren Missouri Ameren Illinois Other Ameren

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Accumulated deferred income taxes and investment tax credits $ 2,122 $ 1,906 $ 148 $ 4,176

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The following table presents the components of accumulated deferred income tax assets relating to net operating loss carryforwards and tax credit carryforwards at December 31, 2024 and 2023:

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Total tax credit carryforwards $ 124 $ 7 $ 45 $ 176

(a) Will expire between 2032 and 2043.

(a) No expiration date.

(b) Will expire between 2032 and 2044.

(d) Will expire between 2025 and 2028.

Uncertain Tax Positions

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The state impact of any federal changes remains subject to examination by various states for up to one year after formal notification to the states.

Ameren’s federal tax returns for the 2020, 2021, and 2022 tax years are open, but, at the time of this filing, the Ameren Companies do not have material income tax issues under examination, administrative appeals, or litigation.

Ameren’s federal tax return for the 2023 tax year is open, but, at the time of this filing, the Ameren Companies do not have material income tax issues under examination, administrative appeals, or litigation.

NOTE 13 – RELATED-PARTY TRANSACTIONS

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Based on the outcome of IPA-administered procurement events, Ameren Missouri and Ameren Illinois have entered into energy product agreements by which Ameren Missouri agreed to sell, and Ameren Illinois agreed to purchase, a set amount of MWhs at a predetermined price over a specified period of time.

The following table presents the specified performance period, average price per MWh, and amount of MWhs included in the agreements:

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The following table presents the specified performance period, amount of MWhs, and average price per MWh included in the agreements:

IPA Procurement Event Performance Period MWhs Average Price per MWh

April 2019 January 2020 – December 2021 288,000 $ 35

September 2019 April 2020 – November 2021 170,800 29

September 2020 September 2021 – November 2022 204,800 31

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These agreements have no contractual expiration date, but may be terminated by either party with three years ’ notice.

Ameren Missouri and ATXI are parties to an interconnection agreement that governs the connection of the High Prairie Renewable Energy Center to an ATXI transmission line that allows Ameren Missouri to distribute power generated from the High Prairie Renewable Energy Center.

Ameren Missouri and ATXI are parties to an interconnection agreement that governs the connection of the High Prairie Energy Center to an ATXI transmission line that allows Ameren Missouri to distribute power generated from the High Prairie Energy Center.

Ameren Missouri and Ameren Illinois are parties to interconnection agreements that govern the connection of the Cass County and Boomtown energy centers to Ameren Illinois transmission lines that allows Ameren Missouri to distribute power generated from the Cass County and Boomtown energy centers.

Support Services Agreements

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See Note 4 – Short-term Debt and Liquidity for a discussion of affiliate borrowing arrangements.

Long-Term Debt, Net - Related Parties

In November and December 2024, Ameren (parent) purchased senior secured notes and first mortgage bonds issued by Ameren Missouri, and first mortgage bonds issued by Ameren Illinois.

See Note 5 – Long-term Debt and Equity Financings for additional information.

Tax Allocation Agreement

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(b) Included in “Accounts receivable – affiliates” on the balance sheet .

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Capital Contributions

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with Ameren Illinois 2023 2 (a)

Ameren Missouri and Ameren Illinois Operating Revenues 2023 32 (b)

Ameren Missouri and Ameren Illinois Operating Revenues 2024 31 1

rent and facility services 2023 32 (b)

Ameren Missouri and Ameren Illinois Operating Revenues 2023 (b) 2

Ameren Missouri and Ameren Illinois Operating Revenues 2024 2 2

miscellaneous support services 2023 (b) 2

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Ameren Missouri and Ameren Illinois Purchased Power 2024 9 2

transmission services from ATXI 2022 1 (b)

transmission services from ATXI 2023 2 1

Total Purchased Power 2024 $ 9 $ 2

Ameren Missouri and Ameren Illinois Other Operations and 2023 $ (b) $ 3

Ameren Missouri and Ameren Illinois Other Operations and 2024 $ 1 $ 1

rent and facility services Maintenance 2023 (b) 3

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Maintenance Expenses 2023 148 141

Money pool borrowings (advances) (Interest Charges) 2023 $ (b) $ (b)

Money pool borrowings (advances) (Interest Charges) 2024 $ ( 4 ) $ (b)

Other Income, Net 2023 (b) (b)

Long-term debt, net - related parties (Interest Charges) 2024 (b) (b)

(a) Not applicable.

(b) Amount less than $ 1 million.

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NOTE 14 – COMMITMENTS AND CONTINGENCIES

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Our electric generation, transmission, and distribution and natural gas distribution and storage operations must comply with a variety of statutes and regulations relating to the protection of the environment and human health and safety, including permitting programs implemented by federal, state, and local authorities.

Such environmental laws address air emissions;

discharges to water bodies;

the storage, handling and disposal of hazardous substances and waste materials;

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;

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

We employ dedicated personnel knowledgeable in environmental matters to oversee our business activities’ compliance with requirements of environmental laws.

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 power plants.

Regulations under the Clean Air Act that apply to the electric utility industry include the NSPS, the CSAPR, the MATS, and the National Ambient Air Quality Standards, which are subject to periodic review for certain pollutants.

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.

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

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

Regulations implementing the Clean Water Act govern both intake and discharges of water, as well as evaluation of the ecological and biological impact of those operations, and could require modifications to water intake structures or more stringent limitations on wastewater discharges.

Depending upon the scope of modifications ultimately required by state regulators, capital expenditures associated with these modifications could be significant.

The management and disposal of coal ash is regulated under the Resource Conservation and Recovery Act and the CCR Rule, which require the closure of surface impoundments at Ameren Missouri’s coal-fired energy centers.

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

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

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

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

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

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Additionally, Ameren Missouri’s wind generation facilities may be subject to operating restrictions to limit the impact on protected species.

Since 2021, Ameren Missouri’s High Prairie Renewable Energy Center curtailed nighttime operations from April through October to limit impacts on protected species during the critical biological season.

The extent and duration of future curtailments are unknown at this time as assessment of mitigation technologies is ongoing.

Ameren Missouri does not anticipate these operating curtailments will have a material impact on its results of operations, financial position, or liquidity.

Ameren and Ameren Missouri estimate that they will need to make capital expenditures of $ 90 million to $ 120 million from 2024 through 2028 in order to comply with existing environmental regulations.

Since 2021, Ameren Missouri’s High Prairie Energy Center curtailed nighttime operations from April through October to limit impacts on protected species during the critical biological season.

The extent and duration of future curtailments are currently unknown as assessment of mitigation technologies is ongoing.

In Ameren Missouri’s 2024 electric service regulatory rate review, the MoPSC staff and the MoOPC have recommended reductions to the revenue requirement associated with the nighttime curtailment of the High Prairie Energy Center.

See Note 2 – Rate and Regulatory Matters for additional information.

Ameren and Ameren Missouri estimate that they may need to make capital expenditures of $ 900 million to $ 1 billion from 2025 through 2029 to comply with environmental regulations.

Additional capital expenditures for environmental controls beyond 2029 could be required.

This estimate of capital expenditures includes surface impoundment closure and corrective action measures required by the CCR Rule and modifications to cooling water intake structures at existing power plants under Clean Water Act rules, all of which are discussed below.

In addition to planned retirements of coal-fired energy centers as set forth in the 2023 IRP filed with the MoPSC in September 2023 and as noted below with respect to the NSR and Clean Air Act litigation and Illinois emissions standards, Ameren Missouri’s current plan for compliance with existing air emission regulations includes burning low-sulfur coal and installing new or optimizing existing air pollution control equipment.

The actual amount of capital expenditures required to comply with existing environmental regulations may vary substantially from the above estimates because of uncertainty as to future permitting requirements by state regulators and the EPA, revisions to regulatory obligations, and varying cost of potential compliance strategies, among other things.

The following sections describe the more significant environmental statutes and regulations and environmental enforcement and remediation matters that affect or could affect our operations.

These estimates include capital expenditures that may be necessary to comply with regulations issued by the EPA in 2024 relating to CO 2 emissions and MATS discussed below, assuming these regulations are not revised or overturned.

This estimate of capital expenditures also includes surface impoundment closure and corrective action measures required by the 2015 CCR Rule and modifications to cooling water intake structures at existing power plants under Clean Water Act rules in place prior to 2024, all of which are discussed below.

Congress and the EPA could review and revise compliance requirements.

In addition to planned retirements of coal-fired energy centers that will be included in Ameren Missouri’s 2025 Change to the 2023 PRP and as noted below with respect to the NSR and Clean Air Act litigation and Illinois emissions standards, Ameren Missouri’s current plan for compliance with existing air emission regulations includes burning low-sulfur coal and installing new or optimizing existing air pollution control equipment.

Accordingly, the actual amount of capital expenditures required to comply with existing environmental regulations may vary substantially from the above estimates because of uncertainty as to future permitting requirements by state regulators and the EPA, revisions to regulatory obligations, and varying cost of potential compliance strategies, among other things.

The following sections describe the significant environmental statutes and regulations and environmental enforcement and remediation matters that affect or could affect our operations.

The EPA periodically amends and revises its regulations and proposes amendments to regulations and guidelines, which could ultimately result in the revision of all or part of such regulations.

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Clean Air Act

Federal and state laws, including the CSAPR, regulate emissions of SO 2 and NO x through the reduction of emissions at their source and the use and retirement of emission allowances.

In April 2022, the EPA proposed plans for additional NO x emission reductions from power plants in Missouri, Illinois, and other states through revisions to the CSAPR.

In January 2023, the EPA issued its final disapproval of Missouri’s proposed state implementation plan for addressing the transport of ozone under the Good Neighbor Plan of the Clean Air Act.

The disapproval of the state plan allows the EPA to implement revisions to the CSAPR through a federal implementation plan.

In March 2023, the EPA announced federal implementation plan requirements, which were subsequently published to the Federal Register in June 2023, reducing the amount of NO x allowances available for state budgets and imposing NO x emission limits on electric generating units for Missouri, Illinois, and other states under the Good Neighbor Plan of the Clean Air Act.

In April 2023, the Missouri Attorney General and Ameren Missouri separately filed lawsuits in the United States Court of Appeals for the Eighth Circuit challenging the EPA’s disapproval of the Missouri state plan and sought a stay of the EPA’s disapproval of the Missouri state plan.

The United States Court of Appeals for the Eighth Circuit in May 2023 granted those stay motions thereby preventing the EPA from imposing the federal implementation plan until the court of appeals issues a ruling.

In December 2023, the United States Supreme Court agreed to hear challenges to the Good Neighbor Plan and scheduled oral argument for February 2024, with a decision expected by June 2024.

In April 2022, the EPA proposed the Good Neighbor Rule of the Clean Air Act, which includes additional NO x emission reductions from power plants in Missouri, Illinois, and other states through revisions to the CSAPR.

In January 2023, the EPA issued its final disapproval of Missouri’s proposed state implementation plan for addressing the transport of ozone under the Good Neighbor Rule of the Clean Air Act.

The disapproval of the state plan allowed the EPA to implement revisions to the CSAPR through a federal implementation plan that reduced the amount of NO x allowances available for state budgets and imposed NO x emission limits on electric generating units for Missouri, Illinois, and other states under the Good Neighbor Rule of the Clean Air Act.

Ameren expected a decision on Missouri’s proposed state implementation plan under the Good Neighbor Rule by the United States Court of Appeals for the Eighth Circuit in 2025, but, in February 2025, the EPA requested that the appellate court suspend the case indefinitely and indicated it was reviewing the basis for the disapproval of the state implementation plans, including Missouri’s.

Ameren Missouri complies with the current CSAPR requirements by minimizing emissions through the use of low-sulfur coal, operation of two scrubbers at its Sioux Energy Center, and optimization of existing NO x air pollution control equipment.

Reducing the amount of state budget NO x allowances for compliance with NO x emission limits could result in additional controls being required on Ameren Missouri’s generating units and/or the reduction of operations.

Any additional costs for compliance are expected to be recovered from customers, subject to MoPSC prudence review, through the FAC or higher base rates.

Reducing the amount of state budget NO x allowances for compliance with NO x emission limits under the Good Neighbor Rule could result in additional controls being required on Ameren Missouri’s generating units and/or the reduction of operations.

Any costs for compliance are expected to be recovered from customers, subject to MoPSC prudence review, through the FAC or higher base rates.

CO 2 Emissions Standards

In June 2022, the United States Supreme Court issued its decision in West Virginia v.

EPA, clarifying that there are limits on how the EPA may regulate greenhouse gases absent further direction from the United States Congress.

The court concluded that the EPA’s proposed rules were designed to shift generation from fossil-fuel-fired power plants to renewable energy facilities, which was improper absent specific congressional authorization.

In May 2023, the EPA issued a new proposed rule that would set CO 2 emission standards for new and existing fossil-fuel-fired power plants based on the adoption of carbon capture technology, natural gas co-firing, and co-firing hydrogen fuel to reduce emissions.

If the proposed rule were adopted, the affected fossil-fuel-fired power plants would be required to comply with the rule through a phased-in approach or retire.

Capacity restrictions for coal-fired units could apply as early as 2030.

Larger natural gas-fired power plants would be required to co-fire with hydrogen by 2032, with additional requirements by 2038.

The EPA expects to issue a final rule in 2024.

Legal challenges to the final rule, if adopted as proposed, are expected.

Ameren and Ameren Missouri cannot predict the results of any such challenges or potential impacts of any such regulations on their results of operations, financial position, and liquidity until final regulations are adopted and the merits of such legal challenges are determined.

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

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

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

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

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

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

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

In April 2024, the EPA revised the MATS by establishing a more stringent standard for emissions of particulate matter, as well as requiring the use of continuous emissions monitoring systems.

Compliance with the revised rule is required by July 2027, with a possible one-year extension if certain conditions are met.

Requests for a stay of the revised rule have been denied by the United States Court of Appeals for the District of Columbia Circuit and the United States Supreme Court.

Arguments regarding the legal merits of the revised rule will be considered by the United States Court of Appeals for the District of Columbia Circuit.

Ameren and Ameren Missouri estimate capital expenditures of approximately $ 320 million may be necessary to comply with the final rule assuming it is not revised or overturned.

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

In November 2024, the EPA issued a proposed rule revising the NSPS to limit emissions of NO x from natural gas-fired stationary CTs.

If adopted as proposed, the rule would require such natural gas facilities which began construction after December 13, 2024, to install certain pollution control equipment to limit emissions of NO x .

In addition, the EPA proposed to maintain the current limits for SO 2 at such natural gas facilities.

Ameren and Ameren Missouri cannot predict the potential impacts of any such rule on their results of operations, financial position, and liquidity until a final rule is adopted.

NSR and Clean Air Act Litigation

In January 2011, the United States Department of Justice, on behalf of the EPA, filed a complaint against Ameren Missouri in the United States District Court for the Eastern District of Missouri alleging that projects performed in 2007 and 2010 at the coal-fired Rush Island Energy Center violated provisions of the Clean Air Act and Missouri law.

In January 2017, the district court issued a liability ruling against Ameren Missouri and, in September 2019, entered a remedy order that required Ameren Missouri to install a flue gas desulfurization system at the Rush Island Energy Center and a dry sorbent injection system at the Labadie Energy Center.

Following an appeal from Ameren Missouri, in August 2021, the United States Court of Appeals for the Eighth Circuit affirmed the liability ruling and the district court’s remedy order as it related to the installation of a flue gas desulfurization system at the Rush Island Energy Center, but reversed the order as it related to the installation of a dry sorbent injection system at the Labadie Energy Center.

In September 2023, the district court granted Ameren Missouri’s request to modify the remedy order to allow the retirement of the Rush Island Energy Center in advance of its previously expected useful life in lieu of installing a flue gas desulfurization system.

In its amended remedy order, the district court established an October 15, 2024 retirement date and, in the interim, authorized Ameren Missouri to operate the energy center as directed by the MISO.

The United States Department of Justice is seeking an order from the district court providing for additional mitigation relief.

Ameren Missouri could be required to implement mitigation relief measures, the costs of which could be material and which Ameren Missouri would not expect to recover.

Ameren Missouri is challenging such mitigation claims, noting that the scope of any such potential additional mitigation relief should be limited by the August 2021 court of appeals decision and offset by emission reductions resulting from the accelerated retirement of the Rush Island Energy Center.

The MISO designated the energy center as a system support resource in 2022 and concluded that certain reliability mitigation measures, including transmission upgrades, should occur before the energy center is retired.

The Rush Island Energy Center began operating as a system support resource on September 1, 2022.

In 2023, the MISO extended the system support resource designation through August 2024, and in September 2023, an agreement between Ameren Missouri and the MISO was approved by the FERC that results in the Rush Island Energy Center only operating during peak demand times and emergencies.

The system support resource

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designation and the related agreement are subject to annual renewal and revision.

Construction activities are underway for the transmission upgrades approved by the MISO, with the majority of the upgrades expected to be completed in the fall of 2024.

Ameren Missouri expects to complete the last of the upgrades by mid-2025.

In addition, in August 2023, the FERC approved a settlement agreement for Ameren Missouri’s request for recovery of non-energy costs under the related MISO tariff between Ameren Missouri and certain intervenors, which provided for recovery of substantially all of Ameren Missouri’s requested non-energy costs through August 2023.

In October 2023, Ameren Missouri received FERC approval for the recovery of non-energy costs under the related MISO tariff from September 2023 to August 2024.

Revenues and costs under the MISO tariff are included in the FAC.

Related to this matter, in February 2022, the MoPSC issued an order directing the MoPSC staff to review the planned accelerated retirement of the Rush Island Energy Center.

See Note 2 – Rate and Regulatory Matters for additional information.

In connection with the accelerated retirement of the Rush Island Energy Center, Ameren Missouri is seeking approval from the MoPSC to finance the costs associated with the retirement, including the remaining unrecovered net plant balance associated with the facility, through the issuance of securitized utility tariff bonds pursuant to Missouri’s securitization statute.

In September 2023, the district court modified the remedy order to allow the early retirement of the Rush Island Energy Center in lieu of installing a flue gas desulfurization system.

Ameren Missouri retired the Rush Island Energy Center on

October 15, 2024.

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

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

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

These programs are estimated to cost approximately $ 64 million.

As of December 31, 2024, Ameren and Ameren Missouri each recorded liabilities of $ 40 million and $ 24 million in “Other current liabilities” and “Other deferred credits and liabilities”, respectively, on their consolidated balance sheets and recorded charges of $ 59 million in “Other operations and maintenance” on their consolidated statements of income in 2024 related to the cost of these programs.

In connection with the accelerated retirement of the Rush Island Energy Center, the MoPSC issued an order in June 2024 authorizing Ameren Missouri to finance the costs associated with the retirement, including the remaining unrecovered net plant balance associated with the facility, through the issuance of securitized utility tariff bonds pursuant to Missouri’s securitization statute.

Costs associated with the retirement exclude any additional mitigation relief ordered in the NSR and Clean Air Act litigation discussed above.

The securitized tariff bonds were issued in December 2024.

See Note 2 – Rate and Regulatory Matters for additional information.

As of December 31, 2023, the Rush Island Energy Center had a net plant balance of $ 530 million included in plant to be abandoned, net, within “Property, Plant, and Equipment, Net”.

See Note 1 – Summary of Significant Accounting Policies for additional information regarding plant to be abandoned, net.

Ameren Missouri is unable to predict the ultimate resolution of this matter;

however, such resolution could have a material adverse effect on the results of operations, financial position, and liquidity of Ameren and Ameren Missouri.

Clean Water Act

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Permits for Ameren Missouri’s coal-fired and nuclear energy centers have been issued or are in the process of renewal.

In 2015, the EPA issued a rule to revise the effluent limitation guidelines applicable to steam electric generating units.

These guidelines established national standards for water discharges, prohibit effluent discharges of certain waste streams, and impose more stringent limitations on certain water discharges from power plants by 2025.

To comply with these guidelines, Ameren Missouri installed dry ash handling systems and wastewater treatment facilities at its coal-fired energy centers.

In April 2024, the EPA issued new effluent limitation guidelines that established a zero discharge limit for flue gas desulfurization wastewater, bottom ash transport water, and combustion residual leachate.

Ameren and Ameren Missouri expect the impacts of the new guidelines on their results of operations, financial position, and liquidity to be immaterial.

CCR Management

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Ameren Missouri’s CCR management compliance plan includes installation of groundwater monitoring equipment and groundwater treatment facilities.

Ameren and Ameren Missouri have AROs of $ 40 million recorded on their respective balance sheets as of December 31, 2023, associated with CCR storage facilities.

In April 2024, the EPA revised the CCR Rule to impose groundwater monitoring, and corrective action, closure, and post-closure requirements on certain active and inactive CCR surface impoundments and disposal units not previously included in the 2015 CCR Rule.

Ameren and Ameren Missouri have AROs of $ 46 million associated with CCR storage facilities recorded on their respective balance sheets as of December 31, 2024.

This amount includes an immaterial incremental ARO related to the 2024 CCR Rule, which may be revised as additional site studies are performed.

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

The Ameren Companies are involved in a number of remediation actions to clean up sites impacted by the use or disposal of materials containing hazardous substances.

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The scope of the remediation activities at these former MGP sites may increase as remediation efforts continue.

Considerable uncertainty remains in these estimates because many site-specific factors can influence the actual costs, including unanticipated underground structures, the degree to which groundwater is encountered, regulatory changes, local ordinances, and site accessibility.

Considerable uncertainty remains in these estimates because many site-specific factors can influence the actual costs, including unanticipated underground structures, the degree to which groundwater is impacted, regulatory changes, local ordinances, and site accessibility.

The actual costs and timing of completion may vary substantially from these estimates.

The ICC allows Ameren Illinois to recover MGP remediation and related litigation costs from its electric and natural gas utility customers through environmental cost riders that are subject to annual prudence reviews by the ICC.

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Our operations or those of our predecessor companies involve the use of, disposal of, and, in appropriate circumstances, the cleanup of substances regulated under environmental laws.

We are unable to determine whether such historical practices will result in future environmental commitments, including additional or more stringent cleanup standards, or will affect our results of operations, financial position, or liquidity.

We are unable to determine whether such historical practices will result in future

environmental commitments, including additional or more stringent cleanup standards, or will affect our results of operations, financial position, or liquidity.

Illinois Emission Standards

The CEJA established emission standards that became effective in September 2021.

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

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.

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Subject to conditions in the CEJA, these energy centers may be allowed to exceed the emissions limits in order to maintain reliability of electric utility service.

Ameren Missouri filed its 2023 IRP with the MoPSC in September 2023 to reflect, among other things, the updated scheduled retirement dates of the natural gas-fired energy centers located in the state of Illinois.

NOTE 15 – SUPPLEMENTAL INFORMATION

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Total cash, cash equivalents, and restricted cash $ 328 $ 17 $ 302 $ 272 $ 10 $ 234

Restricted cash included in “Other current assets” primarily represents funds held by an irrevocable Voluntary Employee Beneficiary Association (VEBA) trust, which provides health care benefits for active employees.

Restricted cash included in “Other current assets” represents funds held by an irrevocable Voluntary Employee Beneficiary Association (VEBA) trust, which provides health care benefits for active employees on Ameren’s, Ameren Missouri’s, and Ameren Illinois’ balance sheets and AMF’s restricted cash for payments for securitized utility tariff bonds on Ameren’s and Ameren Missouri’s balance sheets.

Restricted cash included in “Other assets” on Ameren’s and Ameren Illinois’ balance sheets primarily represents amounts collected under a cost recovery rider restricted for use in the procurement of renewable energy credits and amounts in a trust fund restricted for the use of funding certain asbestos-related claims.

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(b) Amounts associated with the allowance for doubtful accounts related to receivables purchased by Ameren Illinois from alternative retail electric suppliers, as required by the Illinois Public Utilities Act.

Table of Conten t s

As of December 31, 2023, accounts receivable balances that were 30 days or greater past due or that were a part of a deferred payment arrangement represented 22 %, 16 %, and 27 %, or $ 114 million, $ 35 million, and $ 79 million, of Ameren’s, Ameren Missouri’s, and Ameren Illinois’ customer trade receivables before allowance for doubtful accounts, respectively.

In comparison, as of December 31, 2022, these percentages were 17 %, 14 %, and 20 %, or $ 107 million, $ 35 million, and $ 71 million, for Ameren, Ameren Missouri, and Ameren Illinois, respectively.

Ameren and Ameren Missouri have lease agreements primarily relating to rail cars and land related to solar generation facilities.

The land leases are related to the Cass County, Boomtown, and Huck Finn energy centers.

See Note 2 – Rate and Regulatory Matters for additional information on the acquisitions.

Rail cars are leased for the transportation of coal to its energy centers.

For rail car leases, we account for the lease and non-lease components as a single lease component, and for the land leases related to solar generation projects, we account for the components separately for each agreement.

Certain of the land leases related to the acquisitions of the Cass County, Boomtown, and Huck Finn energy centers have options to renew or terminate those leases.

Termination and renewal options are not expected to be exercised and are not included in any of the lease measurements used to record the leased assets and liabilities in the tables below.

The following table provides supplemental balance sheet information related to operating leases as of December 31, 2024:

Ameren Ameren Missouri

Other assets $ 72 $ 69

Other current liabilities 5 4

Other deferred credits and liabilities 67 65

Weighted average remaining operating lease term 29 years 30 years

Weighted average discount rate (a)

(a) As an implicit rate is not readily determinable under most of our lease agreements, we use our incremental borrowing rate based on the information available at commencement date in determining the present value of lease payments.

We use an implicit rate when readily determinable.

The following table presents Ameren’s and Ameren Missouri’s remaining maturities of operating lease liabilities as of December 31, 2024:

Ameren Ameren Missouri

Thereafter 131 131

Total lease payments $ 156 $ 153

Less imputed interest 84 84

Total $ 72 $ 69

The following table presents the components of inventories for each of the Ameren Companies at December 31, 2024 and 2023:

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$ 782 $ 4 $ 786

Liabilities incurred — — — 1

Liabilities incurred 21 (c)

Liabilities settled ( 13 ) — ( 13 ) ( 10 ) — ( 10 )

Accretion (c)

33 — 33 32 — 32

Accretion (d)

Change in estimates ( 7 ) — ( 7 ) ( 18 ) — ( 18 )

Ending balance at December 31 $ 787 (a)(d)

Ending balance at December 31 $ 823 (a)(e)

(a) Balance included $ 5 million and $ 19 million in “Other current liabilities” on the balance sheet as of December 31, 2024 and 2023, respectively.

(b) Included in “Other deferred credits and liabilities” on the balance sheet.

(d) The balance as of December 31, 2023, included an ARO related to the decommissioning of the Callaway Enter Center of $ 619 million.

(c) In 2024, Ameren and Ameren Missouri recorded an ARO related to decommissioning for the Cass County, Boomtown, and Huck Finn energy centers.

In addition, as a result of the 2024 CCR Rule, Ameren and Ameren Missouri recorded an increase to their AROs associated with CCR storage facilities.

See Note 14 – Commitments and Contingencies for additional information.

(d) Accretion expense attributable to Ameren Missouri was recorded as a decrease to regulatory liabilities.

(e) The balance as of December 31, 2024, included an ARO related to the decommissioning of the Callaway Enter Center of $ 648 million.

Deferred Compensation

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Ameren $ 299 $ 287 $ 295

Table of Conten t s

Allowance for Funds Used During Construction

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(a) There was an immaterial number of anti-dilutive securities excluded from the earnings per diluted share calculations for the years ended December 31, 2024, 2023, and 2022 related to performance share units and restricted stock units.

Outstanding forward sale agreements as of December 31, 2024 that were anti-dilutive for the year ended December 31, 2024 were excluded from the earnings per diluted share calculation as calculated using the treasury stock method.

The outstanding forward sale agreements as of December 31, 2023, were anti-dilutive for the year ended December 31, 2023, and excluded from the earnings per diluted share calculation as calculated using the treasury stock method.

Table of Conten t s

For additional information about the outstanding forward sale agreements, see Note 5 – Long-term Debt and Equity Financings.

Supplemental Cash Flow Information

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See Note 1 – Summary of Significant Accounting Policies for additional information regarding the operations of Ameren Missouri, Ameren Illinois, and ATXI.

Segment operating revenues and a majority of operating expenses are directly recognized and incurred by Ameren Illinois to each Ameren Illinois segment.

Segment operating revenues and a majority of operating expenses are directly recognized and incurred by Ameren Illinois in each Ameren Illinois segment.

Common operating expenses, miscellaneous income and expenses, interest charges, and income tax expense are allocated by Ameren Illinois to each Ameren Illinois segment based on certain factors, which primarily relate to the nature of the cost.

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An intersegment elimination at Ameren and Ameren Illinois occurs to eliminate these transmission revenues and expenses.

Table of Conten t s

The CODMs for Ameren, Ameren Missouri, and Ameren Illinois are the Chief Executive Officer of Ameren and Chief Financial Officer of Ameren.

The CODMs use net income to evaluate income generated from the segments to make decisions about resources allocated to each segment and assess segment performance.

Net income is also used to monitor budget versus actual results when assessing segment performance.

The following tables present information about the reported revenue and specified items reflected in net income attributable to common shareholders and capital expenditures by segment at Ameren and Ameren Illinois for the years ended December 31, 2024, 2023, and 2022.

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Intersegment revenues 33 1 — 144 — ( 178 ) —

Revenue 3,993 2,089 938 781 — ( 178 ) 7,623

Fuel and purchased power (a)

( 1,071 ) ( 740 ) — — — 130 ( 1,681 )

Natural gas purchased for resale (a)

( 60 ) — ( 260 ) — — — ( 320 )

Other operations and maintenance expenses (a)

( 1,050 ) ( 619 ) ( 230 ) ( 70 ) ( 48 ) 48 ( 1,969 )

Other segment items

Depreciation and amortization ( 917 ) ( 369 ) ( 129 ) ( 167 ) ( 8 ) — ( 1,590 )

Interest income 11 19 1 2 5 ( 5 ) 33

Interest charges 227 89 55 96 (a)

Taxes other than income taxes ( 372 ) ( 75 ) ( 78 ) ( 9 ) ( 13 ) — ( 547 )

Other income, net 196 97 27 26 83 ( 12 ) 417

Interest charges ( 244 ) ( 98 ) ( 63 ) ( 117 ) (b)

( 153 ) 12 ( 663 )

Income taxes (benefit) 87 ( 50 ) ( 56 ) ( 120 ) 56 — ( 83 )

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

Net income (loss) attributable to Ameren common shareholders 559 234 149 323 ( 83 ) — 1,182

Interest income 8 28 1 6 10 ( 12 ) 41

Capital expenditures 2,712 579 264 758 7 ( 1 ) 4,319

Ameren Missouri Ameren Illinois Electric Distribution Ameren Illinois Natural Gas Ameren Transmission Other Intersegment Eliminations Ameren

External revenues $ 3,825 $ 2,217 $ 897 $ 561 $ — $ — $ 7,500

Intersegment revenues 34 1 — 116 — ( 151 ) —

Revenue 3,859 2,218 897 677 — ( 151 ) 7,500

Fuel and purchased power (a)

( 997 ) ( 933 ) — — — 118 ( 1,812 )

Natural gas purchased for resale (a)

( 79 ) — ( 276 ) — — — ( 355 )

Other operations and maintenance expenses (a)

( 1,003 ) ( 532 ) ( 237 ) ( 60 ) ( 67 ) 33 ( 1,866 )

Other segment items

Depreciation and amortization ( 783 ) ( 351 ) ( 108 ) ( 138 ) ( 7 ) — ( 1,387 )

Interest income 28 7 — — 1 ( 1 ) 35

Interest charges 213 74 44 84 (a)

Taxes other than income taxes ( 360 ) ( 75 ) ( 67 ) ( 8 ) ( 12 ) — ( 522 )

Other income, net 130 103 30 28 62 ( 5 ) 348

Interest charges ( 227 ) ( 89 ) ( 55 ) ( 96 ) (b)

( 104 ) 5 ( 566 )

Income taxes (benefit) 8 ( 82 ) ( 50 ) ( 106 ) 47 — ( 183 )

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

Net income (loss) attributable to Ameren common shareholders 545 258 134 296 ( 81 ) — 1,152

Interest income 11 19 1 2 5 ( 5 ) 33

Capital expenditures 1,760 752 299 804 9 ( 27 ) 3,597

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Intersegment revenues 34 1 — 105 — ( 140 ) —

Revenue 4,046 2,256 1,180 615 — ( 140 ) 7,957

Fuel and purchased power (a)

( 1,150 ) ( 984 ) — — — 114 ( 2,020 )

Natural gas purchased for resale (a)

( 104 ) — ( 553 ) — — — ( 657 )

Other operations and maintenance expenses (a)

( 1,028 ) ( 580 ) ( 253 ) ( 60 ) ( 42 ) 26 ( 1,937 )

Other segment items

Depreciation and amortization ( 732 ) ( 332 ) ( 98 ) ( 123 ) ( 4 ) — ( 1,289 )

Interest income 26 1 — — 3 ( 3 ) 27

Interest charges 137 74 42 83 (a)

Taxes other than income taxes ( 363 ) ( 75 ) ( 82 ) ( 9 ) ( 10 ) — ( 539 )

Other income, net 99 60 19 17 32 ( 1 ) 226

Interest charges ( 213 ) ( 74 ) ( 44 ) ( 84 ) (b)

( 72 ) 1 ( 486 )

Income taxes (benefit) 10 ( 68 ) ( 46 ) ( 92 ) 20 — ( 176 )

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

Net income (loss) attributable to Ameren common shareholders 562 202 123 263 ( 76 ) — 1,074

Interest income 28 7 — — 1 ( 1 ) 35

Capital expenditures 1,690 621 308 741 7 ( 16 ) 3,351

(a) Ameren Transmission interest charges include an allocation of financing costs from Ameren (parent).

Table of Conten t s

(a) Significant segment expense that is regularly provided to the CODMs.

Intersegment expenses are included within the amounts shown.

(b) Ameren Transmission interest charges include an allocation of financing costs from Ameren (parent).

Ameren Illinois

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Intersegment revenues — — 119 ( 119 ) —

Revenue 2,089 938 564 ( 119 ) 3,472

Purchased power (a)

( 740 ) — — 119 ( 621 )

Natural gas purchased for resale (a)

— ( 260 ) — — ( 260 )

Other operations and maintenance expenses (a)

( 619 ) ( 230 ) ( 57 ) — ( 906 )

Other segment items

Depreciation and amortization ( 369 ) ( 129 ) ( 121 ) — ( 619 )

Interest income 19 1 1 — 21

Taxes other than income taxes ( 75 ) ( 78 ) ( 4 ) — ( 157 )

Other income, net 97 27 23 — 147

Interest charges ( 98 ) ( 63 ) ( 80 ) — ( 241 )

Income taxes ( 50 ) ( 56 ) ( 87 ) — ( 193 )

Noncontrolling interests – preferred stock dividends ( 1 ) — ( 1 ) — ( 2 )

Net income available to common shareholder 234 149 237 — 620

Interest income 28 1 3 — 32

Capital expenditures 579 264 624 — 1,467

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Intersegment revenues — — 113 ( 113 ) —

Revenue 2,218 897 480 ( 113 ) 3,482

Purchased power (a)

( 933 ) — — 113 ( 820 )

Natural gas purchased for resale (a)

— ( 276 ) — — ( 276 )

Other operations and maintenance expenses (a)

( 532 ) ( 237 ) ( 49 ) — ( 818 )

Other segment items

Depreciation and amortization ( 351 ) ( 108 ) ( 97 ) — ( 556 )

Interest income 7 — — — 7

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

Other income, net 103 30 23 — 156

Interest charges ( 89 ) ( 55 ) ( 60 ) — ( 204 )

Income taxes ( 82 ) ( 50 ) ( 77 ) — ( 209 )

Noncontrolling interests – preferred stock dividends ( 1 ) — ( 1 ) — ( 2 )

Net income available to common shareholder 258 134 215 — 607

Interest income 19 1 1 — 21

Capital expenditures 752 299 680 — 1,731

Ameren Illinois Electric Distribution Ameren Illinois

Natural Gas Ameren Illinois Transmission Intersegment Eliminations Ameren Illinois

External revenues $ 2,256 $ 1,180 $ 320 $ — $ 3,756

Intersegment revenues — — 104 ( 104 ) —

Revenue 2,256 1,180 424 ( 104 ) 3,756

Purchased power (a)

( 984 ) — — 104 ( 880 )

Natural gas purchased for resale (a)

— ( 553 ) — — ( 553 )

Other operations and maintenance expenses (a)

( 580 ) ( 253 ) ( 49 ) — ( 882 )

Other segment items

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

Interest income 1 — — — 1

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

Other income, net 60 19 17 — 96

Interest charges ( 74 ) ( 44 ) ( 50 ) — ( 168 )

Income taxes ( 68 ) ( 46 ) ( 65 ) — ( 179 )

Noncontrolling interests – preferred stock dividends ( 1 ) — ( 1 ) — ( 2 )

Net income available to common shareholder 202 123 188 — 513

Interest income 7 — — — 7

Capital expenditures 621 308 672 — 1,601

Table of Conten t s

(a) Significant segment expense that is regularly provided to the CODMs.

Intersegment expenses are included within the amounts shown.

The following tables present disaggregated revenues by segment at Ameren and Ameren Illinois for the years ended December 31, 2024, 2023, and 2022.

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(a) The following table presents increases/(decreases) in revenues from alternative revenue programs and other revenues not from contracts with customers for the years ended December 31, 2024, 2023, and 2022:

Table of Conten t s

Ameren Missouri Ameren Illinois Electric Distribution Ameren Illinois Natural Gas Ameren Transmission Ameren

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Other revenues not from contracts with customers 7 (a)

10 2 — 19 (a)

Revenues from alternative revenue programs $ ( 5 ) $ 116 $ 49 $ 19 $ 179

Other revenues not from contracts with customers ( 103 ) (a)(b)

6 3 — ( 94 ) (a)(b)

Other revenues not from contracts with customers ( 9 ) (a)

Revenues from alternative revenue programs $ 17 $ 89 $ ( 19 ) $ ( 9 ) $ 78

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(a) Includes net realized gains and losses on derivative power contracts.

(b) Includes $ 10 million and $ 78 million for insurance recoveries related to lost sales associated with the Callaway Energy Center maintenance outage for the years ended December 31, 2022 and 2021, respectively.

(b) Includes $ 10 million for insurance recoveries related to lost sales associated with the Callaway Energy Center maintenance outage for the year ended December 31, 2022.

Ameren Illinois

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CHANGES IN AND DISAGREEMENTS WITH ACCOUNTANTS ON ACCOUNTING AND FINANCIAL DISCLOSURE

Table of Conten t s

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

What changed 10-K

Item 8. Financial Statements and Supplementary Data