Alliant Energy Corporation filings document regulated utility results, financing arrangements, governance matters, and capital-structure disclosures for Alliant Energy and its utility subsidiaries, Interstate Power and Light Company and Wisconsin Power and Light Company. Combined Form 8-K reports furnish quarterly and annual financial results and record material events for the parent company and the IPL and WPL registrants.
Recent filings also cover term loan credit agreements, covenant requirements, common stock distribution agreements, forward sale arrangements, and other financing matters. Proxy materials disclose annual meeting items, director elections, executive compensation, equity awards, shareholder voting matters, and board governance for the Nasdaq-listed common stock.
Alliant Energy Corporation reported first-quarter 2026 net income attributable to common shareowners of $224 million, up from $213 million, with diluted EPS rising to $0.87 from $0.83. Total revenues increased to $1,184 million from $1,128 million as both electric and gas utility revenues grew, partly offset by lower other utility revenues after IPL exited its steam business.
Operating income eased to $249 million from $257 million as higher fuel, gas, depreciation, and operations and maintenance costs more than offset revenue growth. IPL’s quarterly net income declined to $94 million from $110 million, while WPL’s net income increased to $117 million from $110 million.
Alliant generated $368 million of operating cash flow versus $249 million a year earlier and invested $414 million, mainly in utility projects. The company continued to use forward equity under its at-the-market programs and entered new regulatory and customer agreements, including IUC approval for up to 1,000 MW of new wind in Iowa and filings for an approximately 720 MW gas plant and Riverside Energy Center upgrades to support expected large-load data center growth.
Alliant Energy Corporation reported first quarter 2026 GAAP earnings per share of $0.87, up from $0.83 a year earlier. Ongoing EPS, which excludes a $0.05 per share state income tax apportionment benefit, was $0.82 versus $0.83 in 2025.
Total revenues rose to $1.184 billion from $1.128 billion, and net income attributable to common shareowners increased to $224 million from $213 million. Management reaffirmed 2026 consolidated ongoing EPS guidance of $3.36 to $3.46 per diluted share.
Results were driven by higher revenue requirements from increasing rate base at IPL and WPL, investments in generation and energy storage, and higher allowance for funds used during construction, partly offset by higher financing, depreciation, and maintenance expenses and cooler- or warmer-than-normal temperatures, which reduced operating income by an estimated $16 million. Alliant also highlighted data center growth, including a new approximately 370 MW electric service agreement in Iowa.
Vanguard Capital Management reports 19,403,442 shares (7.54%) of Alliant Energy Corp common stock as beneficially owned. The filing states sole dispositive power over 19,403,442 shares and sole voting power over 2,703,980 shares. Ownership is held by Vanguard Capital Management and affiliated Vanguard investment entities.
Vanguard Portfolio Management reports beneficial ownership of 14,626,154 shares of Alliant Energy Corp. The position represents 5.68% of the outstanding common stock as reported for the period ending 03/31/2026. The filer discloses sole voting power over 31,148 shares and sole dispositive power over 14,626,154 shares. The filing states these holdings include securities held for Vanguard funds and managed accounts and is signed on 04/28/2026.
ALLIANT ENERGY CORP Executive Vice President Antonio P. Smyth reported a routine tax-related share disposition. The company withheld 1,259 shares of common stock at $72.18 per share to cover tax obligations tied to the vesting and settlement of restricted stock units.
The footnotes clarify this is not an open-market sale by Smyth but a mechanistic tax-withholding event. After the transaction, he directly holds 20,678 shares of Alliant Energy common stock, reflecting his ongoing equity stake in the company.
ALLEN PATRICK E reported acquisition or exercise transactions in this Form 4 filing.
Alliant Energy Corp director Patrick E. Allen received a grant of 512.996 Deferred Common Stock Units, each tied to the company’s common stock at an indicated value of $73.10 per unit. These units will be settled in common shares when his board service ends and now bring his total deferred units to 45,514.856. The position also reflects adjustments from accrued dividends through a dividend reinvestment transaction exempt from Section 16 under Rule 16a-11.
Alliant Energy Corp director Ignacio A. Cortina received a grant of deferred stock units, acquiring 666.895 Deferred Common Stock Units at an assigned value of $73.10 per unit. Following this award, his total deferred units position is 10,227.316, held directly.
The units represent Deferred Common Stock and will be settled in shares of common stock when Cortina’s service as a director ends. The reported total also reflects adjustments for accrued dividends through a dividend reinvestment transaction exempt from Section 16 under Rule 16a-11.
ALLIANT ENERGY CORP director Stephanie Cox received an award of 547.1960 Deferred Common Stock Units on April 10, 2026. The units are linked to a reference price of $73.1000 per unit and are structured as derivative securities tied to the company’s common stock.
Each deferred unit corresponds to 1 share of common stock, so the award relates to 547.1960 underlying shares. After this grant, Cox directly holds a total of 17,253.4510 deferred units. According to the terms, these units will be settled in shares of common stock when her service as a director ends.
The reported holdings also reflect adjustments for accrued dividends, which were credited through a dividend reinvestment transaction that is exempt from Section 16 under Rule 16a-11. The filing shows no open‑market buying or selling, only this grant/award acquisition of deferred units.
Falotico Nancy Joy reported acquisition or exercise transactions in this Form 4 filing.
ALLIANT ENERGY CORP director Nancy Joy Falotico received a grant of 778.044 Deferred Common Stock Units, tied to an equivalent number of common shares at a reference price of $73.10 per unit. These units will be settled in common stock when she leaves the board.
The holding now totals 19,630.248 Deferred Common Stock Units, reflecting both the new grant and prior balances, including adjustments for accrued dividends through a dividend reinvestment mechanism.
Garcia Michael Dennis reported acquisition or exercise transactions in this Form 4 filing.
ALLIANT ENERGY CORP director Michael Dennis Garcia received a grant of 875.513 Deferred Common Stock Units. These units relate to the company’s common stock and were valued at $73.10 per unit on the grant date. After this award, he holds 25,762.222 deferred units in total. The units will be settled in shares of common stock when his service as a director ends, and the balance includes adjustments for accrued dividends through a dividend reinvestment mechanism.