克瑞拓斯安全防卫美股招股说明书(2026-02-27版)

Common Stock We are offering 14,285,714 shares of our common stock, par value $0.001 per share, pursuant to this prospectus supplement andthe accompanying prospectus. Our common stock is traded on the Nasdaq Global Select Market under the symbol “KTOS.” OnFebruary 25, 2026, the last reported sale price of our common stock on the Nasdaq Global Select Market was $88.23 per share. Investing in our common stock involves a high degree of risk. Please read “Risk Factors” beginning on pageS-4of thisprospectus supplement, on page5of the accompanying prospectus and in the documents incorporated or deemed incorporated by Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved ofthese securities or determined if this prospectus supplement or the accompanying prospectus is truthful or complete. Any Public Offering PriceUnderwriting Discounts and Commissions We have granted the underwriters an option for a period of 30 days to purchase up to an additional 2,142,857 shares of ourcommon stock. If the underwriters exercise the option in full, the total public offering price will be $1,379,999,964, the totalunderwriting discounts and commissions payable by us will be $31,049,999.19, and our total proceeds, before expenses, will be The underwriters expect to deliver the common stock in book-entry form only, through the facilities of The Depository TrustCompany, against payment in immediately available funds on or aboutMarch 2, 2026. TABLE OF CONTENTS PROSPECTUS SUPPLEMENTABOUT THIS PROSPECTUS SUPPLEMENTTRADEMARKS, SERVICE MARKS AND COPYRIGHTSMARKET AND INDUSTRY DATAPROSPECTUS SUPPLEMENT SUMMARYRISK FACTORSSPECIAL NOTE REGARDING FORWARD-LOOKING INFORMATIONUSE OF PROCEEDSDIVIDEND POLICYMATERIAL UNITED STATES FEDERAL INCOME TAX CONSIDERATIONS FOR NON-U.S. HOLDERSCERTAIN ERISA CONSIDERATIONSUNDERWRITINGVALIDITY OF SECURITIESEXPERTSWHERE YOU CAN FIND ADDITIONAL INFORMATIONINCORPORATION OF CERTAIN DOCUMENTS BY REFERENCE PROSPECTUSABOUT THIS PROSPECTUSSUMMARYRISK FACTORSFORWARD-LOOKING STATEMENTSUSE OF PROCEEDSSELLING SECURITY HOLDERSPLAN OF DISTRIBUTIONDESCRIPTION OF CAPITAL STOCKDESCRIPTION OF DEBT SECURITIESDESCRIPTION OF WARRANTSDESCRIPTION OF RIGHTSDESCRIPTION OF UNITSLEGAL OWNERSHIP OF SECURITIESLEGAL MATTERSEXPERTSWHERE YOU CAN FIND ADDITIONAL INFORMATIONINCORPORATION OF CERTAIN INFORMATION BY REFERENCE ABOUT THIS PROSPECTUS SUPPLEMENT This prospectus supplement and the accompanying prospectus are part of an automatic shelf registration statement that we filedwith the Securities and Exchange Commission (“SEC”) as a “well-known seasoned issuer” as defined in Rule 405 under the SecuritiesAct of 1933, as amended (the “Securities Act”), utilizing a “shelf” registration process. This document is in two parts. The first part isthis prospectus supplement, including the documents incorporated by reference, which describes the specific terms of this offering.The second part, the accompanying prospectus, including the documents incorporated by reference, provides more generalinformation. Generally, when we refer to this prospectus, we are referring to both parts of this document combined. We urge you tocarefully read this prospectus supplement and the accompanying prospectus, and the documents incorporated by reference herein and You should rely only on the information contained in this prospectus supplement and the accompanying prospectus, orincorporated by reference herein or therein. Neither we nor the underwriters (nor any of their affiliates) have authorizedanyone to provide you with different information. No underwriter, dealer, salesperson or other person, including us, hasauthorized anyone to give you any information or to represent anything not contained in this prospectus supplement and theaccompanying prospectus. You should not rely on any unauthorized information or representation. Neither we nor theunderwriters (nor any of their affiliates) take any responsibility for, or can provide any assurance as to the reliability of, anyinformation other than the information contained in this prospectus supplement and the accompanying prospectus, orincorporated herein or therein. This prospectus supplement is an offer to sell only the securities offered hereby and only undercircumstances and in jurisdictions where it is lawful to do so. You should assume that the information in this prospectus Unless otherwise mentioned or unless the context requires otherwise, all references in this prospectus to “the Company,” “we,”“us,” “our” and “Kratos” refer to Kratos Defense & Security Solutions, Inc., a Delaware corporation, and its consolidated subsidiaries. TRADEMARKS, SERVICE MARKS AND COPYRIGHTS We own or have rights to trademarks, service marks or trade names that we use in connection with the operation of our business.We also own or have the rights to copyrights that protect the content of our products. Solely for convenience, the trademarks, servicemarks, tradenames