Arqit Quantum Inc美股招股说明书(2026-01-26版)

Up to $125,000,000Ordinary Shares We have entered into an At The Market Offering Agreement, dated January12, 2026 (the “sales agreement”), withCantor Fitzgerald & Co. and H.C. Wainwright & Co., LLC (the “sales agents”), relating to ordinary shares, no par value(“ordinary shares”), offered by this prospectus supplement and the accompanying prospectus. In accordance with theterms of the sales agreement, we may offer ordinary shares from time to time through the sales agents. This prospectussupplement is offering ordinary shares having an aggregate offering price of up to $125,000,000. Our ordinary shares and warrants are listed on The Nasdaq Capital Market under the symbols “ARQQ” and“ARQQW,” respectively. On January23, 2026, the last reported sales price of our ordinary shares was $24.20 per shareand the last reported sales price of our publicly traded warrants was $0.1897 per warrant. Sales of our ordinary shares, if any, pursuant to this prospectus supplement and the accompanying prospectus willbe made by any method permitted by law deemed to be an “at the market offering” as defined in Rule415 under theSecurities Act of 1933, as amended (the “Securities Act”), including in ordinary brokers’ transactions through thefacilities of The Nasdaq Capital Market or otherwise at market prices prevailing at the time of sale, at prices related toprevailing market prices or at negotiated prices, in block transactions or as otherwise permitted by law. The sales agentswill make all sales using commercially reasonable efforts consistent with their normal sales and trading practices onterms mutually agreed upon between the sales agents and us. We also may sell ordinary shares to sales agents, as principals for their own accounts, at a price per share agreedupon at the time of sale. If we sell shares to the sales agents, as principals, we will enter into a separate termsagreement, and we will describe the agreement in a separate prospectus supplement or pricing supplement. The compensation to the sales agents for sales of our ordinary shares pursuant to the sales agreement will be in anamount up to 3.0% of the gross sales price of all ordinary shares sold thereunder. In connection with the sale of theordinary shares on our behalf, sales agents may be deemed to be “underwriters” within the meaning of the SecuritiesAct, and the compensation of the sales agents may be deemed to be underwriting commissions or discounts. We havealso agreed to provide indemnification and contribution to the sales agents with respect to certain liabilities, includingliabilities under the Securities Act or the Securities Exchange Act of 1934, as amended (the “Exchange Act”). We are a “foreign private issuer,” and an “emerging growth company” each as defined under the federal securitieslaws, and, as such, we are subject to reduced public company reporting requirements. See the section entitled“Summary — Implications of Being an Emerging Growth Company and a Foreign Private Issuer” for additionalinformation. Investing in our ordinary shares involves risks. You should review carefully the risks and uncertainties described underthe heading “Risk Factors” beginning on pageS-6of this prospectus supplement and on page6of the accompanyingprospectus, and under similar headings in any amendment or supplements to this prospectus supplement or theaccompanying prospectus. Neither the Securities and Exchange Commission nor any state securities commission has approved or disapprovedof these securities or passed upon the adequacy or accuracy of this prospectus supplement. Any representation to thecontrary is a criminal offense. H.C. Wainwright & Co. Cantor The date of this prospectus supplement is January 26, 2026 TABLE OF CONTENTS Prospectus Supplement ABOUT THIS PROSPECTUS SUPPLEMENTS-1CAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTSS-2SUMMARYS-3THE OFFERINGS-5RISK FACTORSS-6USE OF PROCEEDSS-7DESCRIPTION OF EQUITY SECURITIESS-8DILUTIONS-9PLAN OF DISTRIBUTIONS-10LEGAL MATTERSS-12EXPERTSS-12WHERE YOU CAN FIND MORE INFORMATIONS-12DOCUMENTS INCORPORATED BY REFERENCES-13 ABOUT THIS PROSPECTUS1INDUSTRY AND MARKET DATA2CAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTS3COMPANY OVERVIEW4CORPORATE INFORMATION4IMPLICATIONS OF BEING AN EMERGING GROWTH COMPANY AND A FOREIGN PRIVATEISSUER4RISK FACTORS6OFFER STATISTICS AND EXPECTED TIMETABLE7USE OF PROCEEDS8DESCRIPTION OF SECURITIES9DESCRIPTION OF EQUITY SECURITIES10DESCRIPTION OF DEBT SECURITIES11DESCRIPTION OF WARRANTS13PLAN OF DISTRIBUTION14ENFORCEMENT OF CIVIL LIABILITIES15EXPENSES18LEGAL MATTERS19EXPERTS19WHERE YOU CAN FIND MORE INFORMATION20 ABOUT THIS PROSPECTUS SUPPLEMENT This document is in two parts. The first part, the prospectus supplement, including the documentsincorporated by reference therein, describes the specific terms of this offering and certain matters relating tous. The second part, the accompanying prospectus, including the documents incorporated by referencetherein, provides mo