Kaiser Aluminum Corp — Current Report (Form 8-K)

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): November 5, 2025

KAISER ALUMINUM CORPORATION

(Exact Name of Registrant as Specified in Its Charter)

(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:

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

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. ☐

On November 5, 2025, Kaiser Aluminum Corporation (the “Company”) issued $500,000,000 aggregate principal amount of its 5.875% Senior Notes due 2034 (the “Notes”) pursuant to an indenture, dated November 5, 2025 (the “Indenture”), among the Company, the subsidiary guarantors party thereto (the “Guarantors”) and Computershare Trust Company, N.A., as trustee (the “Trustee”). The Notes were offered and sold either to persons reasonably believed to be “qualified institutional buyers” pursuant to Rule 144A under the Securities Act of 1933 (the “Securities Act”) or to non-U.S. persons outside the United States under Regulation S of the Securities Act.

The Notes mature on March 1, 2034. Interest accrues on the Notes at a rate of 5.875% per annum from November 5, 2025, and interest is payable semiannually on March 1 and September 1 of each year. The first interest payment date is March 1, 2026. The Company may redeem all or part of the Notes at any time on or after March 1, 2029 at established redemption prices. At any time prior to March 1, 2029, the Company may also redeem up to 40.0% of the Notes using the proceeds from certain equity offerings at a redemption price equal to 105.875% of the principal amount. At any time prior to March 1, 2029, the Company may redeem some or all of the Notes at a price equal to 100% of the principal amount, plus accrued and unpaid interest, if any, to the date of redemption, plus a “make-whole premium.” If the Company sells certain assets or experiences specific kinds of changes in control in connection with a ratings decline, the Company will be required to make an offer to purchase the Notes.

The Indenture contains customary terms and covenants, including that upon certain events of default occurring and continuing, either the Trustee or certain holders of at least 25% in aggregate principal amount of the Notes then outstanding may declare the entire principal amount of all the Notes, and the interest accrued on such Notes, to be immediately due and 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.

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

(d) Exhibits.

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.

- 3 -