ALLIANT ENERGY CORP

Financial Results Overview -The table below includes diluted EPS for Utilities and Corporate Services, ATC Holdings, and Non-utility and Parent, which are non-GAAP financial measures. Alliant Energy believes these non-GAAP financial measures are useful to investors because they facilitate an understanding of performance and trends, and provide additional information about Alliant Energy’s operations on a basis consistent with the measures that management uses to manage its operations and evaluate its performance. Alliant Energy’s net income and diluted EPS attributable to Alliant Energy common shareowners for the three months ended June 30 were as follows (dollars in millions, except per share amounts):

Alliant Energy’s Utilities and Corporate Services net income decreased by $42 million for the three-month period, primarily due to higher other operation and maintenance, financing and depreciation expenses, the timing of income taxes and estimated temperature impacts on retail electric and gas sales. These items were partially offset by higher revenue requirements from IPL’s and WPL’s capital investments.

Alliant Energy’s Non-utility and Parent net income increased $36 million for the three-month period, primarily due to higher equity earnings from corporate venture investments and the timing of income taxes, partially offset by higher financing expense.

Net Income Variances -The following items contributed to increased (decreased) net income for the three and six months ended June 30, 2026 compared to the same periods in 2025 (in millions):

Electric and Gas Revenues and Sales Summary -Electric and gas revenues (in millions), and MWh and Dth sales (in thousands), for the three and six months ended June 30 were as follows:

Sales Trends and Temperatures - Alliant Energy’s retail electric sales volumes increased 1% and remained unchanged for the three and six months ended June 30, 2026, respectively, compared to the same periods in 2025, primarily due to higher sales to commercial and industrial customers at WPL, partially offset by changes in temperatures. Alliant Energy’s retail gas sales volumes decreased 5% and 5% for the three and six months ended June 30, 2026, respectively, compared to the same periods in 2025, primarily due to changes in temperatures.

Estimated increases (decreases) to operating income from the impacts of temperatures for the three and six months ended June 30 were as follows (in millions):

Electric Sales for Resale -Alliant Energy’s and IPL’s wholesale sales volumes decreased for the three and six months ended June 30, 2026, respectively, compared to the same periods in 2025, primarily due to the expiration of IPL’s wholesale power agreement with Southern Minnesota Energy Cooperative in 2025.

Bulk power and other volume changes were due to changes in sales in the wholesale energy markets operated by MISO. These changes are impacted by several factors, including the availability and dispatch of Alliant Energy’s EGUs and electricity demand within these wholesale energy markets. Changes in bulk power and other revenues were largely offset by changes in fuel-related costs, and therefore did not have a significant impact on operating income.

Gas Transportation/Other -Gas transportation/other sales volume changes were largely due to changes in the gas volumes supplied to Alliant Energy’s natural gas-fired EGUs caused by the availability and dispatch of such EGUs.

Electric Utility Revenue Variances -The following items contributed to increased (decreased) electric utility revenues for the three and six months ended June 30, 2026 compared to the same periods in 2025 (in millions):

(a)In December 2025, the PSCW issued an order authorizing an annual base rate increase of $69 million for WPL’s retail electric customers, covering the 2026 forward-looking Test Period, which reflects revenue requirement impacts of increasing electric rate base, including wind refurbishment projects, energy storage, existing natural gas-fired EGU improvements and electric distribution investments and lower forecasted fuel-related expenses.

(b)Sales for resale bulk power and other revenues decreased for the three months ended June 30, 2026 compared to the same period in 2025, primarily due to lower volumes and lower prices for electricity sold by WPL to MISO wholesale energy markets. Sales for resale bulk power and other revenues increased for the six months ended June 30, 2026 compared to the same period in 2025, primarily due to higher volumes and higher prices for electricity sold by IPL and WPL to MISO wholesale energy markets. These changes were largely offset by changes in fuel-related costs.

Gas Utility Revenue Variances -The following items contributed to increased (decreased) gas utility revenues for the three and six months ended June 30, 2026 compared to the same periods in 2025 (in millions):

(a)In December 2025, the PSCW issued an order authorizing an annual base rate increase of $7 million for WPL’s retail gas customers, covering the 2026 forward-looking Test Period, which reflects revenue requirement impacts of increasing gas rate base.

Electric Production Fuel and Purchased Power Expenses Variances -The following items contrib uted to (increased) decreased electric production fuel and purchased power expenses for the three and six months ended June 30, 2026 compared to the same periods in 2025 (in millions):

(a)Purchased power expense decreased for the three and six months ended June 30, 2026 compared to the same periods in 2025, primarily due to lower prices for electricity purchased and lower volumes purchased at IPL.

(b)Electric production fuel costs decreased for the three months ended June 30, 2026 compared to the same period in 2025, primarily due to lower natural gas volumes at IPL and WPL due to lower dispatch of natural gas-fired EGUs and lower coal volumes at WPL due to lower dispatch of coal-fired EGUs, partially offset by higher natural gas prices. Electric production fuel costs increased for the six months ended June 30, 2026 compared to the same period in 2025, primarily due to higher natural gas prices and higher natural gas volumes at WPL due to higher dispatch of natural gas-fired EGUs, partially offset by lower coal volumes at WPL due to lower dispatch of coal-fired EGUs and lower natural gas volumes at IPL due to lower dispatch of natural gas-fired EGUs.

Electric Transmission Service Expense Variances -The following items contributed to (increased) decreased elec tric transmission service expense for the three and six months ended June 30, 2026 compared to the same periods in 2025 (in millions):

Cost of Gas Sold Expense Variances -The following items contributed to (increased) decreased cost of gas sold expense for the three and six months ended June 30, 2026 compared to the same periods in 2025 (in millions):

Other Operation and Maintenance Expenses Variances -The following items contributed to (increased) decreased other operation and maintenance expenses for the three and six months ended June 30, 2026 compared to the same periods in 2025 (in millions):

LIQUIDITY AND CAPITAL RESOURCES

The liquidity and capital resources summary included in the 2025 Form 10-K has not changed materially, except as described below.

Liquidity Position -At June 30, 2026, Alliant Energy had $25 million of cash and cash equivalents, $542 million ($152 million at the parent company, $173 million at IPL and $217 million at WPL) of available capacity under the single revolving credit facility and no available capacity at IPL under its sales of accounts receivable program.

Capital Structure - The following table shows financial capital structures as of June 30, 2026, as well as an adjusted capitalization structure that Alliant Energy believes is consistent with how a majority of the rating agencies currently view its junior subordinated notes (in millions):

(a)The long-term debt component of Alliant Energy’s financial capital structure includes junior subordinated notes classified as “Long-term debt, net” on Alliant Energy’s balance sheet. The adjusted presentation attributes 50% of the junior subordinated notes to common equity and 50% to long-term debt, to align with the debt-to-capital ratio used by the majority of rating agencies. The non-GAAP adjusted presentation reflecting this treatment is useful and relevant to investors in understanding how management and the rating agencies evaluate Alliant Energy’s capital structure.

Cash Flows -Selected information from the cash flows statements was as follows (in millions):

Operating Activities -The following items contributed to increased (decreased) operating activity cash flows for the six months ended June 30, 2026 compared to the same period in 2025 (in millions):

(a)Refer to the cash flows statements for details of renewable tax credits transferred to other corporate taxpayers during the six months ended June 30, 2026 and 2025.

Investing Activities - The following items contributed to increased (decreased) investing activity cash flows for the six months ended June 30, 2026 compared to the same period in 2025 (in millions):

(a)Largely due to lower expenditures for IPL’s energy storage and refurbishment of existing wind farms, partially offset by higher expenditures for WPL’s refurbishment of existing wind farms.

Financing Activities - The following items contributed to increased (decreased) financing activity cash flows for the six months ended June 30, 2026 compared to the same period in 2025 (in millions):

Common Stock Issuances - Refer to Note 5 for discussion of common stock issuances by Alliant Energy in 2026 and Alliant Energy’s at-the-market offering programs.

Short-term Debt - Refer to Note 6(a) for discussion of Alliant Energy’s term loan credit agreement entered into in 2026.

Long-term Debt - Refer to Note 6(b) for discussion of issuances and/or retirements of long-term debt by Alliant Energy, AEF and IPL in 2026.

Impact of Credit Ratings on Liquidity and Collateral Obligations -

Ratings Triggers - In March 2026, Standard & Poor’s Ratings Services changed certain IPL credit ratings, which are not expected to have a material impact on Alliant Energy’s and IPL’s liquidity or collateral obligations. Alliant Energy’s, IPL’s and WPL’s current credit ratings and outlooks are as follows:

Off-Balance Sheet Arrangements and Certain Financial Commitments -A summary of Alliant Energy’s and IPL’s off-balance sheet arrangements and Alliant Energy’s, IPL’s and WPL’s contractual obligations is included in the 2025 Form 10-K and has not changed materially from the items reported in the 2025 Form 10-K, except for the items described in Notes 3,6 and 12.