AMEREN CORP

RESULTS OF OPERATIONS

Our results of operations and financial position are affected by many factors. Economic conditions, energy-efficiency investments by our customers and by us, technological advances, distributed generation, and the actions of key customers can significantly affect the demand for our services. Ameren and Ameren Missouri results are also affected by seasonal fluctuations in winter heating and summer cooling demands and by weather conditions, such as storms, as well as by energy center maintenance outages. Additionally, fluctuations in interest rates and conditions in the capital and credit markets affect our cost of borrowing, our pension and postretirement benefits costs, the cash surrender value of COLI, and the asset value of Ameren Missouri’s nuclear decommissioning trust fund. Almost all of Ameren’s revenues are subject to state or federal regulation. This regulation has a material impact on the rates we charge customers for our services. Our results of operations, financial position, and liquidity are affected by our ability to align our overall spending, both operating and capital, with the frameworks established by our regulators. See Note 2 – Rate and Regulatory Matters under Part II, Item 8, of this report for additional information regarding Ameren Missouri’s, Ameren Illinois’, and ATXI’s regulatory frameworks.

We are observing inflationary pressures on the prices of labor, services, materials, and supplies, as well as high interest rates. Ameren Missouri and Ameren Illinois are generally allowed to pass on to customers prudently incurred costs for fuel, purchased power, and natural gas supply. Additionally, for certain non-commodity cost changes, the use of trackers, riders, formula ratemaking, and future test years, as applicable, mitigates our exposure.

Ameren Missouri principally uses coal and enriched uranium for fuel in its electric operations and purchases natural gas for its customers. Ameren Illinois purchases power and natural gas for its customers. The prices for these commodities can fluctuate significantly because of the global economic and political environment, weather, supply, demand, inflation, and many other factors. We have natural gas cost recovery mechanisms for our Illinois and Missouri natural gas distribution businesses, a purchased power cost recovery mechanism for Ameren Illinois’ electric distribution business, and a FAC for Ameren Missouri’s electric business.

We employ various risk management strategies to reduce our exposure to commodity risk and other risks inherent in our business. The reliability of Ameren Missouri’s energy centers and our transmission and distribution systems and the level and timing of operations and maintenance costs and capital investment are key factors that we seek to manage in order to optimize our results of operations, financial position, and liquidity.

Earnings Summary

The following table presents a summary of Ameren’s earnings for the years ended December 31, 2023 and 2022:

Net income attributable to Ameren common shareholders in 2023 increased $78 million, or $0.24 per diluted share, from 2022. The increase was due to net income increases of $56 million, $33 million, and $11 million at Ameren Illinois Electric Distribution, Ameren Transmission, and Ameren Illinois Natural Gas, respectively. The increases in net income were partially offset by a net income decrease of $17 million at Ameren Missouri and an increase in the net loss for activity not reported as part of a segment, primarily at Ameren (parent), of $5 million.

Earnings per share in 2023, compared with 2022, were favorably affected by:

•increased rate base investments at Ameren Transmission and Ameren Illinois Electric Distribution and a higher recognized ROE due to a higher annual average of the monthly yields of the 30-year United States Treasury bonds at Ameren Illinois Electric Distribution, which increased revenues at these segments (25 cents per share);

•increased base rate revenues at Ameren Missouri effective July 9, 2023, pursuant to the June 2023 MoPSC electric rate order, partially offset by the amortization of previously deferred depreciation expense under the PISA and RESRAM, financing costs otherwise recoverable under the PISA and RESRAM, a lower base level of expenses included in trackers, and the net recovery for amounts associated with the reduction in sales volumes resulting from MEEIA programs (12 cents per share);

•decreased other operations and maintenance expenses not subject to formula rates, riders, or trackers, including an increase in the cash surrender value of COLI, primarily at Ameren Missouri and Ameren Illinois Natural Gas (11 cents per share);

•decreased income tax expense not subject to formula rates or riders due, in part, to decreased income tax expense recognized at Ameren (parent) because of changes in the state income taxes apportioned to Missouri and Illinois, reflecting changes in revenues, as well as the effect of favorable market returns on COLI, compared with unfavorable returns in the year-ago period (6 cents per share);

•increased base rate revenues at Ameren Missouri for the inclusion of previously deferred PISA and RESRAM interest charges pursuant to the December 2021 and June 2023 MoPSC electric rate orders effective February 28, 2022, and July 9, 2023, respectively, partially offset by increased interest charges resulting from lower deferrals related to infrastructure investments associated with the PISA and RESRAM (6 cents per share);

•decreased taxes other than income taxes, primarily at Ameren Missouri, largely resulting from employee retention tax credits received under the Coronavirus Aid, Relief, and Economic Security Act in 2023 (3 cents per share);

•increased Ameren Illinois Natural Gas earnings from investments in qualifying infrastructure recovered under the QIP (3 cents per share);

•increased other income, net, largely due to increased non-service cost components of net periodic benefit income not subject to formula rates or trackers (3 cents per share); and

•recovery of previously incurred expenses at Ameren Illinois Electric Distribution (2 cents per share).

Earnings per share in 2023, compared with 2022, were unfavorably affected by:

•decreased retail sales at Ameren Missouri and Ameren Illinois Natural Gas, primarily due to milder winter and summer temperatures as well as lower sales volumes, excluding the estimated effects of weather, in 2023 (estimated at 25 cents per share);

•increased financing costs at Ameren (parent), Ameren Missouri, and Ameren Illinois Natural Gas, primarily due to higher interest rates on increased levels of short-term borrowings at Ameren (parent), and higher long-term debt balances and higher interest rates on short-term borrowings and long-term debt, partially offset by higher levels of allowance for funds used during construction, at Ameren Missouri and Ameren Illinois Natural Gas (13 cents per share);

•increased weighted-average basic common shares outstanding resulting from issuances of common shares as detailed in Note 5 – Long-term Debt and Equity Financings under Part II, Item 8, of this report (7 cents per share);

•increased depreciation and amortization expenses not recoverable under riders or trackers at Ameren Missouri and Ameren Illinois Natural Gas, primarily due to additional property, plant, and equipment investments (4 cents per share); and

•lower MEEIA 2019 performance incentives recognized at Ameren Missouri (3 cents per share).

The cents per share variances above are presented on the weighted-average basic shares outstanding in 2022 and do not reflect the impact of dilution on earnings per share, unless otherwise noted. The amounts above other than variances related to income taxes have been presented net of income taxes using Ameren’s 2023 blended federal and state statutory tax rate of 26%. For additional details regarding the Ameren Companies’ results of operations, including explanations of Electric and Natural Gas Margins, Other Operations and Maintenance Expenses, Depreciation and Amortization Expenses, Taxes Other Than Income Taxes, Other Income, Net, Interest Charges, and Income Taxes, see the major headings below.

Below is Ameren’s table of income statement components by segment for the years ended December 31, 2023 and 2022:

Below is Ameren Illinois’ table of income statement components by segment for the years ended December 31, 2023 and 2022:

Margins

Electric margins are defined as electric revenues less fuel and purchased power costs. Natural gas margins are defined as natural gas revenues less natural gas purchased for resale. We consider electric and natural gas margins useful measures to analyze the change in profitability of our electric and natural gas operations between periods. We have included the analysis below as a complement to the financial information we provide in accordance with GAAP. However, these margins may not be a presentation defined under GAAP, and they may not be comparable to other companies’ presentations or more useful than the GAAP information we provide elsewhere in this report.

Electric Margins

(a)Includes other/intersegment eliminations of $(32) million and $(25) million in 2023 and 2022, respectively.

Natural Gas Margins

(a)Includes other/intersegment eliminations of $(1) million and $(1) million in 2023 and 2022, respectively.

The following table presents the favorable (unfavorable) variations by segment for electric and natural gas margins in 2023, compared with 2022:

(a)Includes an increase in transmission electric margins of $56 million in 2023, compared with 2022, at Ameren Illinois.

(b)For Ameren Illinois Electric Distribution and Ameren Transmission, base rates include increases or decreases to operating revenues related to the revenue requirement reconciliation adjustment under formula rates. For Ameren Missouri, base rates exclude an increase for the recovery of lost electric margins resulting from the MEEIA customer energy-efficiency programs and a decrease in base rates for RESRAM. These changes in Ameren Missouri base rates are included in the “Sales volumes and changes in customer usage patterns (excluding the estimated effects of weather and MEEIA)” and “Cost recovery mechanisms - offset in fuel and purchased power” line items, respectively.

(c)Represents the estimated variation resulting primarily from changes in cooling and heating degree days on electric and natural gas demand compared with the prior year; this variation is based on temperature readings from the National Oceanic and Atmospheric Administration weather stations at local airports in our service territories.

(d)Electric and natural gas revenue changes are offset by corresponding changes in “Fuel,” “Purchased power,” and “Natural gas purchased for resale” on the statement of income, resulting in no change to electric and natural gas margins. Activity in Other/Intersegment Eliminations represents the elimination of related-party transactions between Ameren Missouri, Ameren Illinois, and ATXI, as well as Ameren Transmission revenue from transmission services provided to Ameren Illinois Electric Distribution. See Note 13 – Related-party Transactions and Note 16 – Segment Information under Part II, Item 8, of this report for additional information on intersegment eliminations.

(e)Offsetting expense increases or decreases are reflected in “Other operations and maintenance,” “Depreciation and amortization,” or in “Taxes other than income taxes” within the “Operating Expenses” section of the statement of income. These items have no overall impact on earnings.

Ameren

Ameren’s electric margins increased $66 million, or 1%, in 2023, compared with 2022, because of increased margins at Ameren Transmission and Ameren Illinois Electric Distribution, as discussed below. Ameren’s natural gas margins decreased $13 million, or 2%, between years because of decreased margins at Ameren Missouri and Ameren Illinois Natural Gas, as discussed below.

Ameren Transmission’s margins increased $62 million, or 10%, in 2023, compared with 2022. Base rate revenues were favorably affected by higher recoverable expenses (+$38 million) and increased capital investment (+$24 million), as evidenced by a 10% increase in rate base used to calculate the revenue requirement.

Ameren Missouri’s electric margins were comparable between years. Revenues associated with “Cost recovery mechanisms– offset in fuel and purchased power” increased $82 million in 2023, compared with 2022, due to increased revenue related to the amortization of costs previously deferred under the FAC that were reflected in customer rates. The changes to “Cost recovery mechanisms - offset in fuel and purchased power” are fully offset by “Cost recovery mechanisms - offset in electric revenue,” in the table above, and result in no impact to margins. Ameren Missouri’s 5% exposure to net energy cost variances under the FAC is reflected within “Off-system sales, capacity, and FAC revenues, net” and “Energy costs (excluding the estimated effect of weather)”.

The following items had an unfavorable effect on Ameren Missouri’s electric margins in 2023, compared with 2022:

•Winter temperatures were warmer as heating degree days decreased 22% while spring and summer temperatures were milder as cooling degree days decreased 3%. The aggregate effect of weather decreased margins by an estimated $57 million. The change in margins due to weather is the sum of the “Effect of weather (estimate)” on electric revenues (-$71 million) and the “Effect of weather (estimate)” on fuel and purchased power (+$14 million) in the table above.

•Excluding the estimated effects of weather and the MEEIA customer energy-efficiency programs, electric revenues decreased an estimated $27 million resulting from a decrease in retail sales volumes, due, in part, to customer outages resulting from major storms experienced throughout the service territory in July and August 2023, partially offset by an increase in customer demand charge revenues and an increase in the average retail price per kilowatthour related to changes in customer usage patterns.

•MEEIA 2019 performance incentives decreased revenues $10 million as performance incentives for program years 2021 and 2022 were recognized in 2022, whereas the performance incentive for program year 2023 was recognized in 2023.

•Revenues associated with other cost recovery mechanisms decreased $10 million, primarily due to a decrease in RESRAM revenues, partially offset by an increase in excise taxes and recoverable MEEIA program costs.

•Transmission service charge revenues decreased $9 million, primarily due to lower revenues related to reactive power.

The following items had a favorable effect on Ameren Missouri’s electric margins in 2023, compared with 2022:

•Higher electric base rates, excluding the change in base rates for the MEEIA customer energy-efficiency programs and the RESRAM, resulting from the June 2023 MoPSC electric rate order effective July 9, 2023, partially offset by higher net energy costs included in base rates, increased margins an estimated $57 million. A similar effect resulting from the December 2021 MoPSC electric rate order effective February 28, 2022, increased margins an estimated $37 million. The change in electric base rates is the sum of the change in “Base rates (estimate)” (+$115 million) and the “Effect of higher net energy costs included in base rates” (-$21 million) in the table above.

•Ameren Missouri’s electric margins increased $12 million due to its 5% exposure to net energy cost variances under the FAC. The change in net energy costs is the sum of “Off-system sales, capacity and FAC revenues, net” (-$226 million) and “Energy costs (excluding the estimated effect of weather)” (+$238 million) in the table above. Revenues decreased primarily due to lower off-system sales volumes (-$108 million) related to reduced generation at the Rush Island Energy Center, lower capacity prices (-$101 million) set by the annual MISO auction in April 2023, and lower market prices for energy (-$11 million). Energy costs decreased primarily due to lower fuel costs (+$130 million), lower purchased power costs (+$98 million), and lower capacity costs (+$95 million), partially offset by decreased deferral of expenses under the FAC (-$90 million).

•Transmission service charge expenses decreased $4 million, primarily due to a decrease in charges related to transmission network upgrades.

Ameren Missouri’s natural gas margins decreased $7 million, or 8%, in 2023, compared with 2022. Purchased gas costs decreased $12 million in 2023, compared with 2022, due to lower commodity prices and decreased amortization of deferred natural gas costs related to the extremely cold weather in mid-February 2021. The decreased purchased gas costs are fully offset by a decrease in natural gas revenues under the PGA, resulting in no impact to margin. The decrease in purchased gas cost is reflected in “Cost recovery mechanisms – offset in natural gas revenue” and the associated recoveries from customers is reflected in “Cost recovery mechanisms – offset in natural gas purchased for resale” in the table above. Margins decreased $4 million due to warmer winter temperatures as heating degree days decreased 22%. The change in margins due to weather is the sum of the “Effect of weather (estimate)” on natural gas revenues (-$17 million) and the “Effect of weather (estimate)” on natural gas purchased for resale (+$13 million) in the table above.

Ameren Illinois’ electric margins increased $69 million, or 4%, in 2023, compared with 2022, driven by increased margins at Ameren Illinois Transmission and Ameren Illinois Electric Distribution. Ameren Illinois Natural Gas’ margins decreased $6 million, or 1%, between years.

Ameren Illinois Electric Distribution

Ameren Illinois Electric Distribution’s margins increased $13 million, or 1%, in 2023, compared with 2022. Purchased power costs decreased $51 million in 2023, compared with 2022, primarily due to decreased energy prices (-$54 million), which largely reflect the results of IPA procurement events, and lower volumes due to decreased sales (-$39 million), partially offset by increased revenues related to the amortization of costs previously deferred under riders (+$28 million) and higher costs due to higher capacity prices (+$9 million). The decreased purchased power costs are fully offset by a decrease in electric revenues under the cost recovery mechanisms for purchased power, resulting in no impact to margin. The decrease in purchased power cost is reflected in “Cost recovery mechanisms – offset in electric revenue” and the associated recoveries from customers is reflected in “Cost recovery mechanisms – offset in fuel and purchased power” in the table above.

The following items had a favorable effect on Ameren Illinois Electric Distribution’s margins in 2023, compared with 2022:

•The impact from base rates (+$30 million) increased due to a higher recognized ROE (+$21 million), as evidenced by an increase of 98 basis points in the annual average of the monthly yields of the 30-year United States Treasury bonds, and increased capital investment (+$15 million), as evidenced by a 9% increase in year-end rate base, partially offset by lower recoverable non-purchased power expenses (-$4 million), and the results from 2021 and 2022 revenue requirement reconciliation adjustment true-ups recognized in the subsequent year (-$2 million).

•Revenues associated with customer energy-efficiency program investments increased $18 million due to the recovery of program expenses (+$12 million), increased investment (+$2 million), higher recognized ROE under formula ratemaking (+$2 million), and the results from the 2022 revenue requirement reconciliation adjustment true-up recognized in 2023 (+$2 million).

Revenues associated with other cost recovery mechanisms decreased $33 million in 2023, compared with 2022, primarily due to a lower amount of bad debt costs included in customer rates pursuant to the associated rider.

Ameren Illinois Natural Gas

Ameren Illinois Natural Gas’ margins decreased $6 million, or 1%, in 2023, compared with 2022. Purchased gas costs decreased $277 million in 2023, compared with 2022, primarily due to lower amortization of natural gas costs that were previously deferred under the PGA and lower natural gas prices in 2023. Deferred natural gas costs related to the extremely cold weather in mid-February 2021 were fully recovered from customers by the end of 2022. The decreased purchased natural gas costs are fully offset by a decrease in natural gas revenues under the PGA, resulting in no impact to margin. The decrease in purchased gas cost is reflected in “Cost recovery mechanisms – offset in natural gas revenue” and the associated recoveries from customers is reflected in “Cost recovery mechanisms – offset in natural gas purchased for resale” in the table above.

The following items had an unfavorable effect on Ameren Illinois Natural Gas’ margins in 2023, compared with 2022:

•Revenues associated with other cost recovery mechanisms decreased $18 million, primarily due to decreased revenues for excise taxes.

•Revenues decreased $4 million primarily due to lower sales volumes related to large commercial, industrial, and transportation customers, and lower capacity revenues. Revenues from sales to large commercial, industrial, and transportation customers are excluded from the VBA. See Note 2 - Rate and Regulatory Matters under Part II, Item 8, of this report for additional information regarding the VBA.

•Other miscellaneous revenues decreased $4 million primarily related to the refund of over-recovered costs associated with the COVID-19 pandemic, beginning in April 2023.

The following items had a favorable effect on Ameren Illinois Natural Gas’ margins in 2023, compared with 2022:

•Revenues increased $14 million due to additional investment in natural gas infrastructure under the QIP.

•Revenues increased $6 million due to higher natural gas base rates as a result of the natural gas rate order effective November 28, 2023.

See Note 2 – Rate and Regulatory Matters under Part II, Item 8, of this report for additional information regarding the QIP and 2023 Natural Gas Delivery Service Rate Order.

Ameren Illinois Transmission

Ameren Illinois Transmission’s electric margins increased $56 million, or 13%, in 2023, compared with 2022. Base rate revenues were favorably affected by increased capital investment (+$25 million), as evidenced by a 15% increase in rate base used to calculate the revenue requirement, and higher recoverable expenses (+$31 million).

Other Operations and Maintenance Expenses

(a)Includes $60 million and $60 million at Ameren Transmission in 2023 and 2022, respectively, and other/intersegment eliminations of $34 million and $16 million in 2023 and 2022, respectively.

Ameren

Other operations and maintenance expenses at Ameren decreased $71 million in 2023, compared with 2022. In addition to changes by segment as discussed below, other operations and maintenance expenses increased $18 million in 2023 for activity not reported as part of a segment, as reflected in “Other/Intersegment Eliminations” above, primarily because of an increase in the elimination of the non-service cost component of net periodic benefit income at Ameren Services. The non-service cost component of net periodic benefit cost or income at Ameren Services is allocated to the segments and primarily included in the segments’ other operations and maintenance expenses. Other operations and maintenance expenses were comparable at Ameren Transmission between periods.

The $25 million decrease in Ameren Missouri’s other operations and maintenance expenses in 2023, compared with 2022, was primarily due to the following items:

•The cash surrender value of COLI increased $21 million. The effect of changes in the cash surrender value of COLI resulted in gains of $7 million in 2023, compared with losses of $14 million in 2022.

•The recognition of regulatory assets for previously expensed costs approved for recovery pursuant to the June 2023 MoPSC rate order decreased other operations and maintenance expenses $14 million.

•Renewable development costs decreased $9 million, as the MoPSC order approving CCNs for the Boomtown and Huck Finn solar projects in the first half of 2023 led to increased capitalization of renewable development costs pursuant to anticipated recovery from customers.

•Energy center operating and maintenance costs decreased $3 million, primarily because of the retirement of the Meramec Energy Center in December 2022, partially offset by increased costs related to maintenance outages at other energy centers.

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

•Transmission and distribution storm-related costs increased $7 million because of the major storms experienced throughout the service territory in July and August 2023.

•Transmission and distribution expenditures, excluding storm costs, increased $7 million, primarily because of increased inspection and vegetation management expenditures.

•MEEIA customer energy-efficiency program spend increased $3 million, as approved by the MoPSC.

Other operations and maintenance expenses decreased $64 million at Ameren Illinois in 2023, compared with 2022, as discussed below. Other operations and maintenance expenses were comparable at Ameren Illinois Transmission between 2023 and 2022.

Ameren Illinois Electric Distribution

The $48 million decrease in Ameren Illinois Electric Distribution’s other operations and maintenance expenses in 2023, compared with 2022, was primarily due to the following items:

•Bad debt costs decreased $43 million primarily because of a lower amount of costs recovered from customers pursuant to the associated rider.

•The cash surrender value of COLI increased $10 million in 2023, primarily because of favorable market returns, compared with unfavorable market returns in 2022.

•Pension and benefit costs decreased $8 million, primarily related to decreased pension service costs due to changes in actuarial assumptions.

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

•Amortization of regulatory assets associated with customer energy-efficiency investments under formula ratemaking increased $9 million.

•Amortization of previously deferred storm-related costs and costs related to major storm activity in 2023, increased $6 million.

Ameren Illinois Natural Gas

Other operations and maintenance costs decreased $16 million in 2023, compared with 2022, in part, because of a $5 million increase in the cash surrender value of COLI. In 2023, the effect of changes in the cash surrender value of COLI resulted in a gain of $2 million, compared with a loss of $3 million in 2022. Other operations and maintenance expenses also decreased $5 million in 2023 because of a decline in required environmental remediation work. Additionally, other operations and maintenance expenses decreased $4 million, primarily related to labor overhead costs.

Depreciation and Amortization

(a)Includes other/intersegment eliminations of $7 million and $4 million in 2023 and 2022, respectively.

The $98 million, $51 million, and $42 million increases in depreciation and amortization expenses in 2023, compared with 2022, at Ameren, Ameren Missouri, and Ameren Illinois, respectively, were primarily due to additional property, plant, and equipment across their respective segments.

In addition, Ameren’s and Ameren Missouri’s depreciation and amortization expenses were affected by the following, which include the effect of the additional investments in property, plant, and equipment:

•Increased depreciation and amortization of $51 million, due to the inclusion in base rates of amounts previously deferred under the PISA and RESRAM effective February 28, 2022, and July 9, 2023, pursuant to the December 2021 and June 2023 MoPSC electric rate orders, respectively.

•Depreciation and amortization rate changes pursuant to the electric rate orders noted above, which increased depreciation and amortization expenses by $17 million.

•Increased depreciation and amortization of $6 million, primarily because of electric system capital additions not eligible for deferral under PISA and RESRAM.

•The higher deferral, net of amortization of prior-period deferrals, pursuant to a tracker related to certain excess deferred income taxes, which decreased depreciation and amortization by $17 million.

•Depreciation and amortization expenses reflected a deferral to a regulatory asset of depreciation and amortization expenses pursuant to PISA and RESRAM. The amount of depreciation and amortization expenses included in base rates for PISA and RESRAM deferrals was updated when new customer rates became effective on February 28, 2022, pursuant to the December 2021 MoPSC electric rate order, which incorporated deferrals through September 30, 2021; and when new customer rates became effective July 9, 2023, pursuant to the June 2023 MoPSC electric rate order, which incorporated deferrals through December 31, 2022. The effect of higher deferrals, net of amortization of prior-period deferrals, decreased depreciation and amortization expenses by $5 million.

•The higher net under-recovery of RESRAM eligible expenses decreased depreciation and amortization expenses by $3 million.

Taxes Other Than Income Taxes

(a)Includes $8 million and $9 million at Ameren Transmission in 2023 and 2022, respectively, and other/intersegment eliminations of $12 million and $10 million in 2023 and 2022, respectively.

Taxes other than income taxes decreased $17 million in 2023, compared with 2022, largely because of a $14 million decrease in excise taxes at Ameren Illinois Natural Gas, primarily resulting from decreased sales revenues. Taxes other than income taxes also decreased $6 million and $2 million in 2023, at Ameren Missouri and Ameren Illinois, respectively, because of employee retention tax credits received under the Coronavirus Aid, Relief, and Economic Security Act. The decreases in taxes other than income taxes at Ameren Missouri were partially offset by a $4 million increase in excise taxes, primarily related to increased retail electric rates pursuant to the June 2023 MoPSC electric rate order.

See Excise Taxes in Note 15 – Supplemental Information under Part II, Item 8, of this report for additional information.

Other Income, Net

See Note 6 – Other Income, Net under Part II, Item 8, of this report for additional information. See Note 10 – Retirement Benefits under Part II, Item 8, of this report for more information on the non-service cost components of net periodic benefit income.

Ameren

Other income, net, increased $122 million in 2023, compared with 2022. In addition to changes discussed below, other income, net, increased $26 million, primarily because of a $30 million increase in the non-service cost component of net periodic benefit income for activity not reported as part of a segment, partially offset by a $3 million increase in charitable contributions.

Other income, net, increased $11 million in 2023, compared with 2022, largely because of a $5 million increase in the allowance for equity funds used during construction, primarily resulting from a higher average monthly equity-to-debt ratio at ATXI, and higher average construction work in progress balances. Other income, net, also increased $3 million because of an increase in the non-service cost component of net periodic benefit income.

Other income, net, increased $31 million in 2023, compared with 2022, primarily because of a $42 million increase in the non-service cost component of net periodic benefit income pursuant to the June 2023 MoPSC electric rate order, which reflected the effect of such increase in electric service rates effective July 9, 2023. Other income, net, also increased $6 million because of higher allowance for equity funds used during construction, resulting from higher average construction work in progress balances. Additionally, other income, net increased $6 million because of higher interest income on under-recovered asset balances associated with regulatory recovery mechanisms. These increases in other income, net, were partially offset by a decrease of $23 million in interest income on industrial development revenue bonds, as these bonds were settled in December 2022 and January 2023. See Note 5 – Long-term Debt and Equity Financings under Part II, Item 8, of this report for additional information on the termination of the financing obligation agreements related to the investments in industrial development revenue bonds.

Other income, net, increased $60 million in 2023, compared with 2022, primarily because of increases in the non-service cost component of net periodic benefit income of $26 million, $11 million, and $3 million at Ameren Illinois Electric Distribution, Ameren Illinois Natural Gas, and Ameren Illinois Transmission, respectively. Other income, net, also increased $13 million at Ameren Illinois Electric Distribution because of higher interest income on under-recovered balances associated with regulatory recovery mechanisms.

Interest Charges

Interest charges increased $80 million in 2023, compared with 2022, primarily because of the following items:

See Note 4 – Short-term Debt and Liquidity under Part II, Item 8, of this report and the Long-term Debt and Equity section below for additional information on short-term borrowings and long-term debt, respectively, discussed below. See Note 5 – Long-term Debt and Equity Financings under Part II, Item 8, of this report for additional information on the termination of the financing obligation agreement discussed below.

Ameren

Interest charges increased $80 million in 2023, compared with 2022. In addition to changes by segments discussed below, interest charges increased $28 million for activity not reported as part of a segment, primarily because of a $23 million increase related to higher interest rates on increased levels of short-term borrowings at Ameren (parent). Interest charges for activity not reported as part of a segment also increased $5 million because of issuances of long-term debt at Ameren (parent) in November and December 2023.

Interest charges increased $12 million in 2023, compared with 2022, primarily because of issuances of long-term debt in August and November 2022 and May 2023, which collectively increased interest charges by $17 million. The increases in 2023 were partially offset by a $8 million reduction to interest charges because of an increase in the borrowed funds capitalized as part of the allowance for funds used during construction, primarily due to increased average construction work in progress balances and a higher applicable borrowing rate.

Interest charges increased $14 million in 2023, compared with 2022. The following items increased interest charges between years:

•Issuances of long-term debt in April 2022 and March 2023 collectively increased interest charges by $27 million.

•Interest charges increased $11 million because of higher interest rates on increased levels of short-term borrowings.

•Interest charges reflected a deferral to a regulatory asset of interest charges pursuant to PISA and RESRAM. The amount of PISA and RESRAM deferrals included in base rates was updated when new customer rates became effective on February 28, 2022, pursuant to the December 2021 MoPSC electric rate order, which incorporated deferrals through September 30, 2021, and when new customer rates became effective July 9, 2023, pursuant to the June 2023 MoPSC electric rate order, which incorporated deferrals through December 31, 2022. Lower deferrals in 2023, due to the inclusion in base rates of interest associated with certain property, plant, and equipment previously deferred under the PISA and RESRAM, increased interest charges by $9 million.

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

•Interest charges decreased $23 million, primarily due to the termination of a financing obligation agreement related to the CT energy center in Audrain County. The decreases in interest charges associated with this agreement are offset by decreases in interest income on related industrial development revenue bonds, as discussed above.

•Interest charges decreased $14 million because of an increase in the borrowed funds capitalized as part of the allowance for funds used during construction, primarily due to higher average construction work in progress balances and a higher applicable borrowing rate.

Interest charges increased $36 million in 2023, compared with 2022, primarily because of the issuances of long-term debt in 2022 and 2023. Issuances of long-term debt at Ameren Illinois in August and November 2022 and May 2023 collectively increased interest charges by $19 million at Ameren Illinois Electric Distribution, by $15 million at Ameren Illinois Transmission, and $12 million at Ameren Illinois Natural Gas. The increases in 2023 were partially offset by a $4 million reduction to interest charges at Ameren Illinois Transmission because of an increase in the borrowed funds capitalized as part of the allowance for funds used during construction, primarily due to higher average construction work in progress balances and a higher applicable borrowing rate.

Income Taxes

The following table presents effective income tax rates for the years ended December 31, 2023 and 2022:

See Note 12 – Income Taxes under Part II, Item 8, of this report for information regarding reconciliations of effective income tax rates for Ameren, Ameren Missouri, and Ameren Illinois.