9.75% Senior NotesDue 2031 We are offering $125,000,000 aggregate principal amount (5,000,000 units, each unit representing $25) of our 9.75%Senior Notes due 2031 (the “notes”). The notes will bear interest at a rate equal to 9.75% per year, payable quarterly inarrears on March1, June1, September1 and December1 of each year, beginning on September1, 2026. The notes willmature on June1, 2031. The notes will be issued in minimum denominations of $25 and integral multiples of $25 in excessthereof or inunits (each unit representing $25). We may redeem the notes, in whole or in part, at any time and from time to time on or after June1, 2028 at aredemption price equal to 100% of the principal amount redeemed plus accrued and unpaid interest to, but excluding, theredemption date. Upon a Change of Control Repurchase Event, we will be required to make an offer to repurchase alloutstanding notes at a price in cash equal to 101% of the principal amount of the notes, plus accrued and unpaid interest to,but not including, the repurchase date. See “Description of the Notes — Offer to Repurchase Upon a Change of ControlRepurchase Event.” The notes will be our senior unsecured obligations and will rank equal in right of payment with our other existing andfuture senior unsecured indebtedness and senior in right of payment to any indebtedness that is contractually subordinatedto the notes. The notes, however, will be effectively subordinated in right of payment to our existing and future securedindebtedness to the extent of the value of the collateral securing such indebtedness, and structurally subordinated to theclaims of our subsidiaries’ creditors, including trade creditors. The notes are a new issue of securities and there is no established trading market for the notes. We intend to apply forlisting of the notes on the New York Stock Exchange (the “NYSE”) under the symbol “RWTS.” If approved for listing, tradingon the NYSE is expected to begin within 30days of May 27, 2026, the original issue date. The notes are expected to trade“flat,” meaning that purchasers will not pay, and sellers will not receive, any accrued and unpaid interest on the notes that isnot included in the trading price. Investing in the notes involves risks that are described under the caption “Risk Factors” beginning on pageS-6of this prospectus supplement and in ourAnnual Report on Form10-K for the fiscal year ended December31,2025and as updated by our subsequent Quarterly Reports on Form10-Q and Current Reports on Form8-K, whichare incorporated by reference in this prospectus supplement. Per NoteTotalPublic offering price$25.00$ 125,000,000Underwriting discount$ 0.7875$3,937,500Proceeds to us (before expenses)$ 24.2125$ 121,062,500(1)(2) (2)See “Underwriting” for a description of additional compensation payable by us to the underwriters. Neither the Securities and Exchange Commission, or SEC, nor any state securities commission has approvedor disapproved of these securities or determined if this prospectus supplement or the accompanying prospectusis truthful or complete. Any representation to the contrary is a criminal offense. We have also granted the underwriters an option to purchase within 30days from the date of this prospectussupplement up to an additional $18,750,000 principal amount (750,000 units, each unit representing $25) of notes from usat the initial public offering price less the underwriting discounts and commissions solely to cover over-allotments, if any. The underwriters expect to deliver the notes in book-entry form only through the facilities of The Depository TrustCompany on or about May 27, 2026, for the accounts of its participants, including Clearstream Banking, société anonyme,and Euroclear BankS.A./N.V., as operator of the Euroclear System. Joint Book-Running Managers Morgan StanleyRBC Capital Markets Wells Fargo Securities Goldman Sachs &Co. LLC Piper Sandler Co-Managers Seaport Global Securities Mischler Financial Group, Inc. The date of this prospectus supplement is May 19, 2026 CONTENTS PROSPECTUS SUPPLEMENT PageAbout This Prospectus SupplementS-iiForward-Looking StatementsS-iiiSummaryS-1The OfferingS-3Risk FactorsS-6Use of ProceedsS-10Description of the NotesS-11UnderwritingS-23Legal MattersS-28ExpertsS-28Where You Can Obtain More InformationS-29Incorporation of Certain Information by ReferenceS-29 PROSPECTUS About This Prospectus1Risk Factors2Cautionary Statement3Redwood Trust,Inc.5Use of Proceeds6General Description of Securities7Description of Debt Securities8Description of Common Stock16Description of Preferred Stock17Description of Securities Warrants18Description of Rights to Purchase Shares of Common or Preferred Stock19Description of Units20Global Securities21Restrictions on Ownership and Transfer and Repurchase of Shares24Certain Provisions of Maryland Law and of Our Charter and Bylaws26Material U.S. Federal Income Tax Considerations29Plan of Distribution58Validity of the Securities59