DEFSEC Technologies Inc. 美股招股说明书（2026年6月26日版）

DEFSEC Technologies Inc. (formerly KWESST Micro Systems Inc.) (the "Company" or "DEFSEC") is offering 673,006 commonshares, no par value per share (each, a "Common Share") at an offering price of CAD$3.74 per share directly to certain accreditedinvestors pursuant to this prospectus supplement and the accompanying base prospectus (the "Offering"). In a concurrent private placement, we are also offering to the purchasers of the Common Shares 673,006 warrants (the "Warrants") topurchase up to 673,006 Common Shares. Each Warrant has an exercise price of CAD$4.39 per common share. The Common Sharesissuable upon exercise of the Warrants are collectively referred to as the "Warrant Shares." The Warrants are immediately exercisableand will expire five years following the date of issuance. The Warrants and the Warrant Shares are not being registered under theSecurities Act of 1933, as amended (the "Securities Act"), pursuant to the registration statement of which this prospectus supplementand the accompanying base prospectus form a part and are not being offered pursuant to this prospectus supplement and the Our Common Shares are listed on the Nasdaq Capital Market (the "Nasdaq") under the stock symbol "DFSC", listed for trading on theTSX Venture Exchange (the "TSXV") under the stock symbol "DFSC", and listed on the Frankfurt Stock Exchange under the stocksymbol of "62U". Certain of our outstanding common share warrants are listed for trading on Nasdaq under the trading symbol As of the date of this prospectus supplement, the aggregate market value of our outstanding Common Shares held by non-affiliates, orour public float, was US$9.82 million based on 1,984,819 outstanding Common Shares held by non-affiliates on June 24, 2026 and aper share price of US$4.95, which was the closing price of our Common Shares on May 12, 2026 and is the highest closing sale priceof our Common Shares on Nasdaq within the prior 60 days. In no event will we sell securities pursuant to a Registration Statement onForm F-3 in a public primary offering with value exceeding more than one-third of our public float in any 12-month calendar period solong as our public float remains below US$75 million and General Instruction I.B.5 of Form F-3 continues to apply to us. As of the We are an emerging growth company and a smaller reporting company under Rule 405 of the Securities Act, and, as such, have electedto comply with certain reduced public company reporting requirements for this prospectus supplement, the accompanying base The sales of the Common Shares will be made in accordance with securities purchase agreements, dated as of June 24, 2026, by andbetween us and the investors named therein (the "Securities Purchase Agreement"). We have engaged H.C. Wainwright & Co., LLC to act as our placement agent (the "Placement Agent") in connection with thisOffering. The Placement Agent is not purchasing or selling any of the securities offered pursuant to this prospectus supplement and theaccompanying base prospectus. We will bear all costs associated with the Offering. See "Plan of Distribution" on pageS-14of this Investing in these securities involves certain risks. See "Risk Factors" on pageS-11of this prospectus supplement and theaccompanying base prospectus, as well as the risk factors incorporated by reference into this prospectus supplement andaccompanying base prospectus for a discussion of the factors you should carefully consider before deciding to purchase these We have prepared this prospectus supplement in accordance with United States disclosure requirements. Our financialstatements are prepared in accordance with International Financial Reporting Standards as issued by the InternationalAccounting Standards Board and thus may not be comparable to financial statements of United States companies. Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of thesesecurities or determined if this prospectus supplement or accompanying base prospectus is truthful or complete. Anyrepresentation to the contrary is a criminal offense. (1) We have agreed to pay the Placement Agent a cash fee equal to 7.5% of the aggregate gross proceeds of this Offering. Inaddition, we have agreed to issue to the Placement Agent or its designees, on a private placement basis, warrants topurchase a number of Common Shares equal to 7.5% of the Common Shares sold in this, at an exercise price ofCAD$4.675 per share, which represents 125% of the offering price per share (the "Placement Agent Warrants"). See "Plan The delivery to purchasers of the securities in this Offering is expected to be made on or about June 26, 2026, subject to satisfaction ofcertain customary closing conditions. H.C. Wainwright & Co. The date of this prospectus supplement is June 24, 2026 PROSPECTUS SUPPLEMENT Page ABOUT THIS PROSPECTUS SUPPLEMENTS-1CAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTSS-2PROSPECTUS SUPPLEMENT SUMMA