SEALSQ Corp美股招股说明书(2025-10-20版)

Up to 67,359,998Ordinary Shares of SEALSQ Corp This prospectus supplement relates to the resale, by the selling shareholders identified in this prospectus supplement, of up to67,359,998 Ordinary Shares, par value US$0.01 per share (“Ordinary Shares”), of SEALSQ Corp (the “Company,” “us,” or “we”),consisting of (i) 14,026,666 Ordinary Shares issuable upon exercise of Pre-funded warrants (the “Pre-funded Warrants”) and (ii) 53,333,332Ordinary Shares issuable upon exercise of Class D warrants (the “Class D Warrants,” and together with the Pre-funded Warrants, the“Private Warrants”). The Private Warrants were issued in a private placement concurrently with the sale by the Company of 12,640,000Ordinary Shares in a registered direct offering pursuant to a securities purchase agreement, dated as of October 15, 2025 (the “PurchaseAgreement”). Such Ordinary Shares underlying the Private Warrants are collectively referred to herein as the “Resale Shares.” We areregistering the Resale Shares on behalf of the selling shareholders, to be offered and sold from time to time, to satisfy certain registrationrights that we have granted to the selling shareholders pursuant to the Purchase Agreement. We are not selling any Resale Shares and willnot receive any proceeds from the sale of the Resale Shares by the selling shareholders. The selling shareholders may resell or dispose of the Resale Shares to or through underwriters, broker-dealers, agents, or throughany other means described in the section of this prospectus supplement entitled “Plan of Distribution.” The selling shareholders will bearthe costs of commissions and discounts, if any, attributable to the sale or disposition of the Resale Shares. We will bear all costs, expensesand fees in connection with the registration of the Resale Shares. Our Ordinary Shares are listed on the Nasdaq Capital Market under the symbol “LAES.” The last reported sale price of ourOrdinary Shares on the Nasdaq Capital Market on October 17, 2025 was $6.67 per Ordinary Share. We are an emerging growth company as that term is used in the Jumpstart Our Business Startups Act of 2012 (the “JOBS Act”)and, as such, are subject to certain reduced public company reporting requirements. Investing in our securities involves a high degree of risk and uncertainty. See “Risk Factors” beginning on page S-9 of thisprospectus supplement, onpage 8of the accompanying base prospectus and in the documents incorporated by reference into thisprospectus supplement and accompanying base prospectus concerning factors you should consider before investing in oursecurities. Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved ofthesesecurities or determined if this prospectus supplement or accompanying prospectus is truthful or complete.Anyrepresentation to the contrary is a criminal offense. Prospectus Supplement dated October 20, 2025 PROSPECTUS SUPPLEMENT ABOUT THIS PROSPECTUS SUPPLEMENTS-iiCAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTSS-1PROSPECTUS SUPPLEMENT SUMMARYS-4THE OFFERINGS-8RISK FACTORSS-9USE OF PROCEEDSS-10SELLING SHAREHOLDERSS-11DESCRIPTION OF ORDINARY SHARESS-13CERTAIN TAX CONSIDERATIONSS-14PLAN OF DISTRIBUTIONS-15LEGAL MATTERSS-17EXPERTSS-17ENFORCEABILITY OF CIVIL LIABILITIESS-17WHERE YOU CAN FIND MORE INFORMATIONS-17INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCES-17 PROSPECTUS ABOUT THIS PROSPECTUS1ABOUT OUR COMPANY2RISK FACTORS8FORWARD-LOOKING STATEMENTS23CAPITALIZATION28USE OF PROCEEDS29DESCRIPTION OF ORDINARY SHARES30DESCRIPTION OF WARRANTS38DESCRIPTION OF SUBSCRIPTION RIGHTS41DESCRIPTION OF UNITS42TAXATION43SELLING SHAREHOLDERS44PLAN OF DISTRIBUTION45LEGAL MATTERS47EXPERTS47INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCE47WHERE YOU CAN FIND MORE INFORMATION49ENFORCEABILITY OF CIVIL LIABILITIES49 ABOUT THIS PROSPECTUS SUPPLEMENT This prospectus supplement and the accompanying base prospectus are part of a registration statement on Form F-3 (RegistrationNo. 333-290963), that we filed with the United States Securities and Exchange Commission (“SEC”) using a “shelf” registration process.The accompanying base prospectus provides you with a general description of us and the securities that may be offered, some of which donot apply to this offering. The prospectus supplement contains specific information about the terms of this offering by the sellingshareholders. A prospectus supplement also adds, updates, or changes the information contained in the accompanying base prospectus. This prospectus supplement relates to this offering of our securities by the selling shareholders. To the extent there is a conflictbetween the information contained in this prospectus supplement and the accompanying base prospectus, you should rely on theinformation in this prospectus supplement. This prospectus supplement, the accompanying base prospectus, and the documents weincorporate by reference herein and therein include important information