克利夫兰克里夫美股招股说明书(2025-10-30版)

We are selling 75,000,000 of our common shares, par value $0.125 per share ("common shares"). Our common shares trade on theNew York Stock Exchange ("NYSE") under the symbol “CLF.” On October 28, 2025, the last sale price of the common shares asreported on the NYSE was $14.09 per share. Investing in our common shares involves risks. See “Risk Factors” herein and beginning on page 7 of the accompanyingprospectus. The underwriter proposes to offer the common shares from time to time for sale in one or more transactions on the NYSE, in the over-the-counter market, through negotiated transactions or otherwise at market prices prevailing at the time of sale, at prices related toprevailing market prices or at negotiated prices. See “Underwriting.” The underwriter has agreed to purchase the common shares from us at a price of $12.69 per share, which will result in $951,750,000 ofproceeds to us, before expenses. The underwriter may also exercise its option to purchase up to an additional 11,250,000 common shares from us, at the price per shareset forth above, for 30 days after the date of this prospectus supplement. Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of thesesecurities or determined if this prospectus supplement or the accompanying prospectus is truthful or complete. Anyrepresentation to the contrary is a criminal offense. The shares will be ready for delivery on or about October 31, 2025. UBS Investment Bank The date of this prospectus supplement is October 29, 2025. Prospectus Supplement PageABOUT THIS PROSPECTUS SUPPLEMENTS-iWHERE YOU CAN FIND MORE INFORMATIONS-iINFORMATION WE INCORPORATE BY REFERENCES-iNON-GAAP FINANCIAL MEASURESS-1DISCLOSURE REGARDING FORWARD-LOOKING STATEMENTSS-2SUMMARYS-4RISK FACTORSS-13USE OF PROCEEDSS-16CAPITALIZATIONS-17DESCRIPTION OF CAPITAL STOCKS-18MATERIAL U.S. FEDERAL INCOME TAX CONSEQUENCES TO NON-U.S. HOLDERSS-19UNDERWRITINGS-22LEGAL MATTERSS-28EXPERTSS-28 Prospectus ABOUT THIS PROSPECTUS1WHERE YOU CAN FIND MORE INFORMATION2INFORMATION WE INCORPORATE BY REFERENCE3DISCLOSURE REGARDING FORWARD-LOOKING STATEMENTS4OUR BUSINESS6RISK FACTORS7USE OF PROCEEDS8DESCRIPTION OF CAPITAL STOCK9DESCRIPTION OF DEPOSITARY SHARES11DESCRIPTION OF WARRANTS13DESCRIPTION OF SUBSCRIPTION RIGHTS15DESCRIPTION OF DEBT SECURITIES16DESCRIPTION OF UNITS20PLAN OF DISTRIBUTION21LEGAL MATTERS23EXPERTS23 ABOUT THIS PROSPECTUS SUPPLEMENT We provide information to you about this offering in two separate documents. The accompanying prospectus provides generalinformation about us and the common shares we may offer from time to time, some of which may not apply to this offering. Thisprospectus supplement describes the specific details regarding this offering. Additional information is incorporated by reference into thisprospectus supplement. If information in this prospectus supplement is inconsistent with the accompanying prospectus, you should relyon this prospectus supplement. You should read both this prospectus supplement and the accompanying prospectus together withadditional information under the headings “Where You Can Find More Information” and “Information We Incorporate By Reference.” We have not, and the underwriter has not, authorized anyone to provide you with any information other than that contained orincorporated by reference into this prospectus supplement, the accompanying prospectus or in any free writing prospectus that we mayprovide to you. We and the underwriter take no responsibility for, and can provide no assurance as to the reliability of, any otherinformation that others may give you. You should not assume that the information contained in this prospectus supplement, theaccompanying prospectus or any document incorporated by reference is accurate as of any date other than the date mentioned on thecover page of these documents. We are not, and the underwriter is not, making offers to sell the common shares in any jurisdiction inwhich an offer or solicitation is not authorized or in which the person making such offer or solicitation is not qualified to do so or toanyone to whom it is unlawful to make an offer or solicitation. Except as otherwise indicated or the context otherwise requires, references in this prospectus supplement and the accompanyingprospectus to the terms “we,” “us,” “our,” the “Company” or “Cliffs” or other similar terms mean Cleveland-Cliffs Inc. and its consolidatedsubsidiaries. WHERE YOU CAN FIND MORE INFORMATION We are subject to the informational reporting requirements of the Securities Exchange Act of 1934, as amended, (the “Exchange Act”).We file annual, quarterly and current reports, proxy statements and other information with the SEC. Our SEC filings are available overthe Internet at the SEC’s website at www.sec.gov. We make available, free of charge, on our website at www.clevelandcliffs.com, our annual reports on Form 10-K, quarterly reports onForm 10-Q, current reports