Summary Of Significant Accounting Policies

6 Months Ended

Jun. 30, 2026

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

General

Ameren, headquartered in St. Louis, Missouri, is a public utility holding company whose primary assets are its equity interests in its subsidiaries. Ameren’s subsidiaries are separate, independent legal entities with separate businesses, assets, and liabilities. Dividends on Ameren’s common stock and the payment of expenses by Ameren depend on distributions made to it by its subsidiaries. Ameren’s principal subsidiaries are listed below. Ameren also has other subsidiaries that conduct other activities, such as providing shared services.

•Union Electric Company, doing business as Ameren Missouri, operates a rate-regulated electric generation, transmission, and distribution business and a rate-regulated natural gas distribution business in Missouri.

•Ameren Illinois Company, doing business as Ameren Illinois, operates rate-regulated electric transmission, electric distribution, and natural gas distribution businesses in Illinois.

•ATXI operates a FERC rate-regulated electric transmission business in the MISO.

Ameren’s and Ameren Missouri’s financial statements are prepared on a consolidated basis and therefore include the accounts of their majority-owned subsidiaries. All intercompany transactions have been eliminated. Ameren Illinois has no subsidiaries. All tabular dollar amounts are in millions, unless otherwise indicated.

Note 1 – Summary of Significant Accounting Policies applies to the Ameren Companies. The remaining notes to the consolidated financial statements apply to the registrants as indicated in each footnote disclosure. Registrants are named specifically for their related activities and disclosures.

Our accounting policies conform to GAAP. Our financial statements reflect all adjustments (which include normal, recurring adjustments) that are necessary, in our opinion, for a fair statement of our results. The preparation of financial statements in conformity with GAAP requires management to make certain estimates and assumptions. Such estimates and assumptions affect reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the dates of financial statements, and the reported amounts of revenues and expenses during the reported periods. Actual results could differ from those estimates. The results of operations for an interim period may not give a true indication of results that may be expected for a full year. These financial statements contained in this Form 10-Q should be read in conjunction with the audited financial statements and accompanying notes included in the Form 10-K.

Variable Interest Entities

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 entity, as well as the obligation to absorb losses or the right to receive benefits from the entity that could potentially be significant to the variable interest entity. 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 retired energy center, 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 under Part II, Item 8, of the Form 10-K. For additional information on the securitized tariff bond issuance, see Note 5 – Long-term Debt and Equity Financings under Part II, Item 8, of the Form 10‑K.

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 June 30, 2026 and December 31, 2025:


	2026		2025
Unbilled revenue(a)	$	2	$	2
Other current assets(a)	15		21

Noncurrent regulatory assets(a)	432		443
Current maturities of long-term debt(b)	24		23
Interest accrued(b)	6		6
Current regulatory liabilities(c)	5		11
Long-term debt, net(b)	414		426

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

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

(c)Included in “Other current liabilities” on Ameren’s and Ameren Missouri’s balance sheet.

Variable Interest Entities that are not Consolidated

As of June 30, 2026, and December 31, 2025, Ameren had unconsolidated variable interests in various equity method investments, primarily to advance innovative energy technologies, totaling $82 million and $64 million, respectively, included in “Other assets” on Ameren’s consolidated balance sheet. Any earnings or losses related to Ameren’s share in these investments are included in “Other Income, Net” on Ameren’s consolidated statement of income and comprehensive income. Ameren is not the primary beneficiary of these investments because it does not have the power to direct matters that most significantly affect the activities of these variable interest entities. As of June 30, 2026, Ameren’s maximum exposure to loss related to these variable interest entities is limited to the investment in these partnerships of $82 million plus associated outstanding funding commitments of $25 million.

COLI

Ameren (parent) and Ameren Illinois have COLI, which is recorded at the net cash surrender value. The net cash surrender value is the amount that can be realized under the insurance policies at the balance sheet date. As of June 30, 2026, the cash surrender value of COLI at Ameren and Ameren Illinois was $225 million (December 31, 2025 – $219 million) and $130 million (December 31, 2025 – $126 million), respectively, while total borrowings against the policies were $118 million (December 31, 2025 – $117 million) at both Ameren and Ameren Illinois. Ameren and Ameren Illinois have the right to offset the borrowings against the cash surrender value of the policies and, consequently, present the net asset in “Other assets” on their respective balance sheets. The net cash surrender value of Ameren’s COLI is affected by the investment performance of a separate account in which Ameren holds a beneficial interest.

Accounting and Reporting Developments

See Note 1 – Summary of Significant Accounting Policies under Part II, Item 8, of the Form 10-K for additional information about recently issued authoritative accounting standards related to internal-use software and government grants.

Accounting for Environmental Credit Programs

In May 2026, the FASB issued authoritative guidance that established requirements for the recognition, measurement, presentation, and disclosure of environmental credits and environmental credit obligations. The guidance applies to all entities that generate, purchase, or receive environmental credits, or that have a regulatory compliance obligation that may be settled with environmental credits. The guidance will be effective for the Ameren Companies beginning January 1, 2028. We are currently assessing the impacts of this guidance on our results of operations, financial position, and liquidity.