Momentus美股招股说明书(2026-06-18版)

(to the prospectus dated June4, 2026) Up to $75,000,000of Common Stock Wehave entered into a Sales Agreement,dated September 19,2025,(the“Sales Agreement”),withA.G.P./Alliance Global Partners (“A.G.P.” or the “Sales Agent”) relating to the sale of shares of our ClassAcommon stock, par value $0.00001 per share (“common stock” or “Common Stock”), offered by this prospectussupplement, having an aggregate offering price of up to $75,000,000 from time to time through or to the SalesAgent, acting as sales agent or principal. Sales of shares of our common stock, if any, under this prospectus supplement will be made in sales deemed to be“at the market offerings” as defined in Rule 415(a)(4) promulgated under the Securities Act of 1933, as amended(the “Securities Act”). The Sales Agent is not required to sell any specific amount, but will act as sales agent on acommercially reasonable efforts basis consistent with its normal trading and sales practices, on mutually agreedterms between the Sales Agent and us. There is no arrangement for funds to be received in any escrow, trust orsimilar arrangement. As sales agent, A.G.P. is entitled to compensation at a fixed commission rate equal to 3.0% of the gross proceedsof each sale of shares of our common stock. In connection with the sale of our shares of common stock on ourbehalf, the Sales Agent will be deemed to be an “underwriter” within the meaning of the Securities Act and thecompensation of the Sales Agent will be deemed to be underwriting commissions or discounts. We have alsoagreed to provide indemnification and contribution to the Sales Agent with respect to certain liabilities, includingliabilities under the Securities Act and the Securities Exchange Act of 1934, as amended (the “Exchange Act”).See the section titled “Plan of Distribution” beginning on page S-15for additional information regarding theSales Agent’s compensation. Our common stock is listed on The Nasdaq Stock Market LLC (“Nasdaq”) under the symbol “MNTS.” OnJune17, 2026, the last reported sale price of our common stock on Nasdaq was $10.06 per share. As of the date of this prospectus, the aggregate market value of our outstanding common stock held by non-affiliates is approximately $365 million, which is calculated based on 18,737,791 shares of our outstandingcommon stock held by non-affiliates and a price of $19.50 per share, the closing price of our common stock onMay 27, 2026, which is the highest closing price of our common stock on Nasdaq within the prior 60 days of thisprospectus. Investing in our common stock involves a high degree of risk. Before making an investment decision, pleaseread the information under the heading “Risk Factors” beginning on page S-9 of this prospectussupplement and in the documents incorporated by reference into this prospectus. Neither the Securities and Exchange Commission nor any state securities commission has approved ordisapproved of these securities or passed upon the adequacy or accuracy of this prospectus. Anyrepresentation to the contrary is a criminal offense. TABLE OF CONTENTS Prospectus Supplement PageABOUT THIS PROSPECTUSS-1SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTSS-2PROSPECTUS SUMMARYS-3THE OFFERINGS-8RISK FACTORSS-9USE OF PROCEEDSS-13DIVIDEND POLICYS-13DILUTIONS-14PLAN OF DISTRIBUTIONS-15LEGAL MATTERSS-20EXPERTSS-20WHERE YOU CAN FIND MORE INFORMATIONS-20INCORPORATION OF CERTAIN INFORMATION BY REFERENCES-21 Prospectus PageABOUT THIS PROSPECTUSiiPROSPECTUS SUMMARY1RISK FACTORS8FORWARD-LOOKING STATEMENTS9USE OF PROCEEDS10DESCRIPTION OF CAPITAL STOCK11DESCRIPTION OF DEBT SECURITIES16DESCRIPTION OF WARRANTS22DESCRIPTION OF UNITS24LEGAL OWNERSHIP OF SECURITIES25SELLING STOCKHOLDERS28PLAN OF DISTRIBUTION30LEGAL MATTERS33EXPERTS33WHERE YOU CAN FIND MORE INFORMATION33INCORPORATION OF CERTAIN INFORMATION BY REFERENCE34 TABLE OF CONTENTS ABOUT THIS PROSPECTUS SUPPLEMENT This prospectus supplement relates to part of a registration statement on Form S-3 that we have filed with theSecurities and Exchange Commission (the “SEC”) utilizing a “shelf” registration process. Under this shelfregistration process, we may sell any combination of the securities described in our base prospectus included in theshelf registration statement in one or more offerings up to a total aggregate offering price of $200,000,000. The$75,000,000 of shares of common stock that may be offered, issued and sold under this prospectus supplement isincluded in the $200,000,000 of securities that may be offered, issued and sold by us pursuant to our shelfregistration statement. In connection with such offers and when accompanied by the base prospectus included in theregistration statement of which this prospectus supplement is a part, this prospectus supplement will be deemed aprospectus supplement to such base prospectus. This prospectus supplement relates to the offering of our shares of common stock. Before buying any of our sharesof common stock that we are offering, w