克瑞拓斯安全防卫美股招股说明书(2026-02-27版)

Kratos Defense & Security Solutions, Inc. 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 byreference into this prospectus supplement before investing in our common stock. 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. Anyrepresentation to the contrary is a criminal offense. Public Offering PriceUnderwriting Discounts and CommissionsProceeds to Kratos Defense & Security Solutions, Inc. before expenses 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$1,348,949,964.81. 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. Truist Securities Prospectus Supplement datedFebruary 26, 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 andtherein, before buying any of the securities being offered under this prospectus supplement. This prospectus supplement may add to orupdate information contained in the accompanying prospectus and the documents incorporated by reference therein. To the extent thatany statement we make in this prospectus supplement is inconsistent with statements made in the accompanying prospectus or anydocuments incorporated by reference therein that were filed before the date of this prospectus supplement, the statements made in thisprospectus supplement will be deemed to modify or supersede those made in the accompanying prospectus and such documentsincorporated by reference therein. 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, o