FORM10-K xANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year endedDecember 31, 2024 OR oTRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934For the transition period from__________to__________ Commission File Number:001-34611 Securities registered pursuant to Section 12(b) of the Act: Securities registered pursuant to Section 12(g) of the Act:None Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act.YesxNoo Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or 15(d) of the Act. YesoNox Indicate by check mark whether the registrant: (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to suchfiling requirements for the past 90 days.YesxNoo Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submitsuch files).YesxNoo Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company, oran emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company” and “emerging growthcompany” in Rule 12b-2 of the Exchange Act. If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with anynew or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act.o Indicate by check mark whether the registrant has filed a report on and attestation to its management’s assessment of the effectiveness of its internalcontrol over financial reporting under Section 404(b) of the Sarbanes-Oxley Act (15 U.S.C. 7262(b)) by the registered public accounting firm thatprepared or issued its audit report.x If securities are registered pursuant to Section 12(b) of the Act, indicate by check mark whether the financial statements of the registrant included inthe filing reflect the correction of an error to previously issued financial statements.o Indicate by check mark whether any of those error corrections are restatements that required a recovery analysis of incentive-based compensationreceived by any of the registrant’s executive officers during the relevant recovery period pursuant to §240.10D-1(b).o Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act). YesoNox The aggregate market value of the common stock held by non-affiliates of the registrant was approximately $9.8billion as of June 30, 2024, on theNasdaq Capital Market. For purposes of the foregoing computation, all executive officers, directors, and 10% beneficial owners of the registrant aredeemed to be affiliates. There were235,129,734shares of common stock outstanding as of February21, 2025. DOCUMENTS INCORPORATED BY REFERENCE Portions of the registrant’s Definitive Proxy Statement to be filed subsequent to the date hereof with the Securities and Exchange Commission (the“SEC”) pursuant to Regulation 14A in connection with the registrant’s 2025 Annual Meeting of Stockholders are incorporated by reference into PartIII of this Report. Such Definitive Proxy Statement will be filed with the SEC no later than 120 days after the conclusion of the registrant’s fiscal yearended December31, 2024. TABLE OF CONTENTS Cautionary Statements Regarding Forward-Looking Statements Item 1.Business1Item 1A.Risk Factors6Item 1B.Unresolved Staff Comments22Item 1C.Cybersecurity22Item 2.Properties23Item 3.Legal Proceedings23Item 4.Mine Safety Disclosures23 Part II24 Item 5.Market For Registrant’s Common Equity, Related Stockholder Matters and Issuer Purchases of Equity Securities24Item 6.[Reserved]25Item 7.Management’s Discussion and Analysis of Financial Condition and Results of Operations26Item 7A.Quantitative and Qualitative Disclosures About Market Risk32Item 8.Financial Statements and Supplementary Data33Item 9.Changes in and Disagreements with Accountants on Accounting and Financial Disclosure33Item 9A.Controls and Procedures33Item 9B.Other Information34Item 9C.Disclosure Regarding Foreign Jurisdictions that Prevent Inspections34 Item 10.Directors, Executive Officers and Corporate Governance35Item 11.Executive Compensation35Item 12.Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters35Item 13.Certain Relationships and Related Transactions, and Director Independence35Item 14.Principal Accountant Fees