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 whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities ExchangeAct of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject tosuch filing 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 toRule 405 of Regulation S-T (§ 232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required tosubmit such files). YesxNoo Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reportingcompany, or an emerging growth company. See the definitions of “large accelerated filer”, “accelerated filer”, “smaller reporting company,” and“emerging growth company” in Rule 12b-2 of the Exchange Act. Large accelerated filerxAccelerated fileroNon-accelerated fileroSmaller reporting companyoEmerging growth companyo If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complyingwith any new 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 itsinternal control 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.☒ If securities are registered pursuant to Section 12(b) of the Act, indicate by check mark whether the financial statements of the registrantincluded in the 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-basedcompensation received 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 Common Stock held by non-affiliates (based on the closing sale price on The Nasdaq Global Select Market onJune 30, 2025) was approximately $11.2 billion. As of February 3, 2026 there were 199,014,486 shares of Common Stock, $.001 par value per share, outstanding. DOCUMENTS INCORPORATED BY REFERENCE Items 10 (as to directors and Section 16(a) Beneficial Ownership Reporting Compliance), 11, 12, 13 and 14 of Part III incorporate by referenceinformation from the registrant’s proxy statement to be filed with the Securities and Exchange Commission in connection with the solicitation of proxiesfor the registrant’s 2026 Annual Meeting of Stockholders to be held on June 8, 2026. Table of Contents Forward-Looking Statements2Summary Risk Factors5 PART I 6 Item 1.BusinessItem 1A.Risk FactorsItem 1B.Unresolved Staff CommentsItem 1C.CybersecurityItem 2.PropertiesItem 3.Legal ProceedingsItem 4.Mine Safety DisclosuresInformation about our Executive Officers Item 5.Market for Registrant’s Common Equity, Related Stockholder Matters and Issuer Purchases ofEquity Securities60Item 6.[Reserved]60Item 7.Management’s Discussion and Analysis of Financial Condition and Results of Operations60Item 7A.Quantitative and Qualitative Disclosures About Market Risk70Item 8.Financial Statements and Supplementary Data71Item 9.Changes in and Disagreements With Accountants on Accounting and Financial Disclosure116Item 9A.Controls and Procedures116Item 9B.Other Information118Item 9C.Disclosure Regarding Foreign Jurisdictions that Prevent Inspections118 Item 10.Directors, Executive Officers and Corporate Governance118Item 11.Executive Compensation119Item 12.Security Ownership of Certain Beneficial Owners and Management and Related StockholderMatters119Item 13.Certain Relationships and Related Transactions, and Director Independence119Item 14.Principal Accountant Fees and Services119 Table of Contents Forward-Looking Statements This report contains forward-looking statements that involve risks and uncertainties. These statements relate tofuture periods, future events or our future operating or financial plans or performance. Often, these statements include thewords “believe,” “expect,” “target,” “anticipate,” “intend,” “plan,” “seek,” “estimate,” “potential,” or words ofsimilar meaning, or future or conditional verbs such as “will,” “would,” “should,” “could,” “might,” or “may,” or thenegative of these terms, and other similar expressions. These forward-looking statements incl