Chubb INA Holdings LLC 4.900% Senior Notes due 2035Fully and Unconditionally Guaranteed by Chubb Limited Chubb INA Holdings LLC (“Chubb INA”) is offering $1,250,000,000 aggregate principal amount of its 4.900% SeniorNotes due 2035 (the “Notes”). The Notes will bear interest at the rate of 4.900% per year. Interest on the Notes is payable semi-annually on February15 and August15 of each year, beginning February15, 2026. The Notes will mature on August 15, 2035.Chubb INA may redeem some or all of the Notes at any time and from time to time at the applicable redemption price discussedunder the caption “Description of the Notes and Guarantee—Optional Redemption.” In addition, Chubb INA may redeem all,but not less than all, of the Notes under the circumstances described under “Description of the Notes and Guarantee—Redemption for Tax Reasons.” The Notes will be issued only in registered form in denominations of $2,000 and integralmultiples of $1,000 in excess thereof. The Notes will be unsecured and rank equally in right of payment with all of Chubb INA’s other unsecured seniorindebtedness from time to time outstanding. The Notes will be fully and unconditionally guaranteed on a senior unsecured basisby Chubb Limited, the ultimate parent corporation of Chubb INA. The Notes are a new issue of securities with no established trading market. The Notes will not be listed on any securitiesexchange or on any automated dealer quotation system. Before investing in the Notes, you should consider the risks included or incorporated by reference herein, as described under“Risk Factors” beginning on pageS-9of this prospectus supplement. (1)Plus accrued interest, if any, from August6, 2025 to date of delivery. Neither the Securities and Exchange Commission (the “SEC”) nor any state securities commission has approved ordisapproved of these securities or determined if this prospectus supplement or the accompanying prospectus is truthful orcomplete. Any representation to the contrary is a criminal offense. The underwriters expect to deliver the Notes to purchasers through the book-entry delivery system of The Depository TrustCompany (“DTC”) for the accounts of its participants, including Clearstream Banking S.A. (“Clearstream”) and Euroclear BankSA/NV (“Euroclear”), on or about August 6, 2025, against payment in immediately available funds. TABLE OF CONTENTS Prospectus Supplement PageForward-Looking StatementsS-1Prospectus Supplement SummaryS-3Risk FactorsS-9Use of ProceedsS-11Capitalization of ChubbS-12Description of the Notes and GuaranteeS-13Certain Tax ConsequencesS-22Underwriting (Conflicts of Interest)S-27Legal MattersS-33Where You Can Find More InformationS-33 Prospectus PageAbout This Prospectus1Chubb Limited3Chubb INA5The Chubb Trusts5Use of Proceeds6General Description of the Offered Securities6Description of Chubb Common Shares6Description of Chubb INA Debt Securities and Chubb Guarantee13Description of the Warrants to Purchase Common Shares28Description of Preferred Securities29Description of Preferred Securities Guarantees38Plan of Distribution43Legal Opinions45Experts45Enforcement of Civil Liabilities Under United States Federal Securities Laws45Where You Can Find More Information46 No person is authorized to give any information or to make any representations other than thosecontained or incorporated by reference into this prospectus supplement, the accompanying prospectus or anyfree writing prospectus that we have authorized and, if given or made, such information or representationsmust not be relied upon as having been authorized. This prospectus supplement, the accompanyingprospectus and any free writing prospectus do not constitute an offer to sell or a solicitation of an offer tobuy any securities other than the securities described in this prospectus supplement or an offer to sell or asolicitation of an offer to buy such securities in any circumstances in which such offer or solicitation isunlawful. Neither the delivery of this prospectus supplement, the accompanying prospectus or any freewriting prospectus, nor any sale made hereunder and thereunder, shall, under any circumstances, create anyimplication that there has been no change in the affairs of Chubb INA or Chubb Limited since the date ofthis prospectus supplement, the accompanying prospectus or any free writing prospectus or that theinformation contained or incorporated by reference herein or therein is accurate as of any time subsequent tothe date of such information. Our business, financial condition, results of operations and prospects mayhave changed since these dates. No offer or solicitation to purchase or invest in the Notes from or in Switzerland shall be made in amanner that would require the preparation and publication of a prospectus pursuant to the Swiss FinancialServices Act (“FinSA”). Neither this prospectus supplement, nor any other offering or marketing materialrelating to the Notes constitutes an offer or solicitation