UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

PURSUANT TO SECTION 13 OR 15(D)

OF THE SECURITIES AND EXCHANGE ACT OF 1934

Date of Report (Date of Earliest Event Reported): ~~October 27~~November 5, 2025

KAISER ALUMINUM CORPORATION

(Exact Name of Registrant as Specified in Its Charter)

Delaware	1-09447	94-3030279
(State or Other Jurisdictionof Incorporation)	(CommissionFile Number)	(IRS EmployerIdentification No.)
(State or Other Jurisdiction of Incorporation)	(Commission File Number)	(IRS Employer Identification No.)
1550 West McEwen Drive
Suite 500
Franklin, Tennessee		37067
(Address of Principal Executive Office)		(Zip Code)

1550 West McEwen Drive
Suite 500
Franklin, Tennessee		37067
(Address of Principal Executive Office)		(Zip Code)

(629) 252-7040

(Registrant’s telephone number, including area code)

Not Applicable

(Former Name or Former Address, if Changed Since Last Report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

☐	Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐	Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐	Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐	Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

Title of each class		~~Tradingsymbol~~Trading symbol(s)		Name of each exchangeon which registered
Common Stock, par value $0.01 per share		KALU		Nasdaq Global Select Market

Indicate by check mark whether the registrant is an emerging growth company as defined in as defined in Rule 405 of the Securities Act of 1933 (17 CFR 230.405) or Rule 12b-2 of the Securities Exchange Act of 1934 (17 CFR 240.12b-2).

Emerging growth company ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standard provided pursuant to Section 13(a) of the Exchange Act. ☐

Item 81.01. ~~Other~~Entry ~~Events~~into a Material Definitive Agreement.

On ~~October 27~~November 5, 2025, Kaiser Aluminum Corporation (the “Company”) issued ~~a press release announcing that it has priced~~ $500.0,000,000 ~~million in~~ aggregate principal amount of its 5.875% ~~senior~~Senior ~~notes~~Notes due 2034 (the “~~New~~ Notes”) pursuant to an indenture, indated aNovember 5, ~~private~~2025 ~~transaction~~(the ~~that~~“Indenture”), isamong ~~exempt~~the ~~from~~Company, the ~~registration~~subsidiary ~~requirements~~guarantors ofparty thereto (the ~~Securities~~“Guarantors”) ~~Act~~and ofComputershare ~~1933~~Trust Company, N.A., as trustee (the “Trustee”). The ~~consummation~~Notes ofwere ~~the~~offered ~~offering~~and ofsold ~~New~~either ~~Notes~~to ispersons ~~expected~~reasonably believed to be ~~completed~~“qualified oninstitutional ~~November~~buyers” 5,pursuant ~~2025,~~to ~~subject~~Rule 144A under the Securities Act of 1933 (the “Securities Act”) or to ~~customary~~non-U.S. ~~closing~~persons ~~conditions~~outside the United States under Regulation S of the Securities Act.

The ~~Company~~Notes ~~intends~~mature toon ~~use~~March 1, 2034. Interest accrues on the ~~net~~Notes ~~proceeds~~at a rate of 5.875% per annum from ~~the~~November 5, ~~offering~~2025, ~~together~~and ~~with~~interest ~~borrowings~~is ~~under~~payable ~~the~~semiannually ~~revolving~~on ~~credit~~March 1 ~~facility~~ and/ September 1 of each year. The first interest payment date is March 1, 2026. The Company may redeem all or ~~cash~~part of the Notes at any time on ~~hand~~or after March 1, 2029 at established redemption prices. At any time prior to March 1, 2029, the Company may also redeem ~~all~~up ~~outstanding~~to ~~amounts~~40.0% of the ~~Company’s~~Notes 4using the proceeds from certain equity offerings at a redemption price equal to 105.~~625~~875% ~~senior~~of ~~notes~~the ~~due~~principal ~~2028~~amount. (At any time prior to March 1, 2029, the ~~“2028~~Company may redeem some or all of the Notes~~”).~~ Aat ~~copy~~a price equal to 100% of the ~~press~~principal ~~release~~amount, isplus ~~attached~~accrued ~~hereto~~and asunpaid ~~Exhibit~~interest, 99if any, to the date of redemption, plus a “make-whole premium.1” If the Company sells certain assets or experiences specific kinds of changes in control in connection with a ratings decline, ~~and~~the isCompany ~~incorporated~~will bybe ~~reference~~required ~~herein~~to make an offer to purchase the Notes.

The ~~information~~Indenture ~~contained~~contains incustomary ~~this~~terms ~~report~~and ~~shall~~covenants, ~~not~~including ~~constitute~~that anupon ~~offer~~certain toevents ~~sell~~of default occurring and continuing, either the Trustee or acertain ~~solicitation~~holders of anat ~~offer~~least to25% ~~purchase,~~in ~~any~~aggregate ~~New~~principal ~~Notes~~amount inof ~~any~~the ~~jurisdiction~~Notes inthen ~~which~~outstanding ~~such~~may andeclare ~~offer,~~the ~~solicitation~~entire orprincipal ~~sale~~amount ~~would~~of beall ~~unlawful~~the Notes, ~~nor~~and ~~does~~the itinterest ~~constitute~~accrued aon ~~notice~~such ofNotes, ~~redemption~~to ~~with~~be ~~respect~~immediately todue ~~the~~and ~~2028 Notes~~payable.

The Company has various relationships with the initial purchasers. Certain of the initial purchasers and their affiliates have engaged, and may in the future engage, in investment banking, commercial banking and other financial advisory and commercial dealings with the Company and its affiliates. In addition, certain of the initial purchasers and/or their affiliates are lenders and/or agents under our existing revolving credit facility. These agents and lenders, or their respective affiliates, have received, and may in the future receive, customary fees and expenses for those services.

The preceding description of the Indenture and the Notes is a summary and is qualified in its entirety by the Indenture and form of the Notes, which are filed as Exhibit 4.1 and Exhibit 4.2, respectively, hereto and are incorporated by reference herein. On November 5, 2025, the Company also issued a press release announcing the completion of the offering. A copy of the press release is attached hereto as Exhibit 99.1, and is incorporated by reference herein.

Item 2.03

Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant.

The information set forth under Item 1.01 above is incorporated by reference into this Item 2.03.

Item 9.01.

Financial Statements and Exhibits.

(d) Exhibits.

Number		Exhibit
99.1		Press release dated October 27, 2025.
4.1		Indenture, dated November 5, 2025, among Kaiser Aluminum Corporation, each of the guarantors named therein and Computershare Trust Company, N.A., as Trustee.
4.2		Form of 5.875% Senior Note due 2034 (included in Exhibit 4.1).
99.1		Press release dated November 5, 2025.
104		Cover Page Interactive Data File (embedded within the Inline XBRL document).

Forward-Looking Statements

This Current Report on Form 8-K contains statements based on management’s current expectations, estimates and projections that constitute “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995 involving known and unknown risks and uncertainties that may cause actual results, performance or achievements of the Company to be materially different from those expressed or implied. These factors include: (a) the effectiveness of management’s strategies and decisions, including strategic investments, capital spending strategies, cost reduction initiatives, sourcing strategies, process and countermeasures implemented to address operational and supply chain challenges, and the execution of those strategies; (b) the execution and timing of strategic investments; (c) general economic and business conditions, including the impact of geopolitical factors and governmental and other actions taken in response, tariffs, cyclicality, reshoring, labor challenges, supply interruptions, scrap availability and pricing, customer operation disruptions, customer inventory imbalances and supply chain issues and other conditions that impact demand drivers in the aerospace/high strength, packaging, general engineering, automotive extrusions and other end markets the Company serves; (d) the Company’s ability to participate in mature and anticipated new automotive programs expected to launch in the future and successfully launch new automotive programs; (e) changes or shifts in defense spending due to competing national priorities; (f) pricing, market conditions and the Company’s ability to effectively execute its commercial and labor strategies, pass through cost increases, including the institution of surcharges, and flex costs in response to inflation, volatile commodity costs and changing economic conditions; (g) developments in technology; (h) the impact of the Company’s future earnings, cash flows, financial condition, capital requirements and other factors on its financial strength and flexibility; (i) new or modified statutory or regulatory requirements; (j) the successful integration of the acquired operations and technologies; (k) stakeholder, including regulator and customer, views regarding the Company’s sustainability goals and initiatives and the impact of factors outside of the Company’s control on such goals and initiatives; and (l) other risk factors summarized in the Company’s reports filed with the Securities and Exchange Commission including the Company’s Form 10-K for the year ended December 31, 2024. All information in this report is as of the date of this report. The Company undertakes no duty to update any forward-looking statement to conform the statement to actual results or changes in the Company’s expectations.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the Registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

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KAISER ALUMINUM CORPORATION

Date: October 27, 2025

/s/ John M. Donnan

Date: November 5, 2025

/s/ John M. Donnan

John M. Donnan Executive Vice President, Chief Administrative Officer and General Counsel

John M. Donnan

Executive Vice President, Chief Administrative Officer and General Counsel

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