伊利诺伊机械美股招股说明书(2026-08-11版)

$% Notes due This is an offering by Illinois Tool Works Inc. of $aggregate principal amount of% notes due(the “notes”). Interest on the notes will be paid semi-annually in arrears onandof each year, beginning on,2027. The notes will mature on, 20. We may redeem all or part of the notes at any time and from time to time at the redemption prices described in thisprospectus supplement. See “Description of Notes — Optional Redemption.” The notes will be our unsecured senior debt obligations and will rank equally with all of our other unsecured andunsubordinated indebtedness from time to time outstanding. The notes will be issued only in denominations of $2,000 andintegral multiples of $1,000 in excess thereof. The notes will not be convertible or exchangeable. Investing in our notes involves risks. You should carefully read the accompanying prospectus,this prospectus supplement and the documents incorporated by reference herein and therein,including the section entitled “Risk Factors” beginning on page S-6 of this prospectus supplement. The information in this preliminary prospectus supplement is not complete and may be changed. This preliminary prospectus supplement and theaccompanying prospectus is not an offer to sell these securities, and it is not soliciting an offer to buy these securities in any jurisdiction where the offeror sale is not permitted.(1)Plus accrued interest, if any, from, 2026 if settlement occurs after that date. Neither the United States Securities and Exchange Commission nor any state securities commission has approved ordisapproved of these securities or determined if this prospectus supplement or the accompanying prospectus is truthfulor complete. Any representation to the contrary is a criminal offense. We expect that delivery of the notes will be made to investors in book-entry form through the facilities of The DepositoryTrust Company and its direct and indirect participants,including Clearstream Banking S.A. (“Clearstream”), and EuroclearBank SA/NV (“Euroclear”), on or about, 2026. Joint Book-Running Managers J.P.Morgan CitigroupBofASecurities GoldmanSachs&Co.LLC Table of Contents Neither we nor the underwriters have authorized anyone to provide you with any information or to make any representation other thanthose contained in or incorporated by reference into this prospectus supplement, the accompanying prospectus or in any free writingprospectus that we may file with the Securities and Exchange Commission (the “SEC”) in connection with this offering. We do not, and theunderwriters do not, take any responsibility for, and can provide no assurances as to, the reliability of any information that others may provideyou. If information in this prospectus supplement is inconsistent with the accompanying prospectus, you should rely on the prospectussupplement. We are not, and the underwriters are not, making an offer of these securities in any state where the offer or sale is not permitted.You should not assume that the information provided in this prospectus supplement, the accompanying prospectus or the documentsincorporated by reference in this prospectus supplement and in the accompanying prospectus is accurate as of any date other than theirrespective dates. Our business, financial condition, results of operations and prospects may have changed since those dates. TABLE OF CONTENTS Prospectus Supplement About This Prospectus SupplementWhere You Can Find More InformationIncorporation of Certain Information by ReferenceSpecial Note Regarding Forward-Looking StatementsSummaryRisk FactorsUse of ProceedsCapitalizationDescription of NotesBook-Entry NotesMaterial U.S. Federal Income Tax ConsequencesUnderwritingLegal MattersExperts Prospectus About This ProspectusThe CompanyWhere You Can Find More InformationIncorporation of Certain Information by ReferenceSpecial Note Regarding Forward-Looking StatementsRisk FactorsUse of ProceedsDescription of Debt SecuritiesPlan of Distribution Experts Legal Matters Table of Contents ABOUT THIS PROSPECTUS SUPPLEMENT This document is in two parts. The first part is this prospectus supplement, which contains the terms of this offering of notes. The second part isthe accompanying prospectus dated as of July9, 2026, which was originally filed as part of our Registration Statement on Form S-3. This prospectus supplement may add to, update or change the information in the accompanying prospectus. If information in this prospectussupplement is inconsistent with information in the accompanying prospectus, this prospectus supplement will apply and will supersede that informationin the accompanying prospectus. It is important for you to read and consider all information contained or incorporated by reference in this prospectus supplement and theaccompanying prospectus in making your investment decision. You should also read and consider the information in the documents to which we havereferred you under “Where You Can Find More Informati