Jade Biosciences Inc美股招股说明书(2026-06-04版)

10,000,000 Shares of Common Stock We are offering 10,000,000shares of our common stock, par value $0.0001 per share, in this offering. Our common stock is listed on the Nasdaq Capital Market (“Nasdaq”) under the symbol “JBIO”. On June3, 2026, the closing price of our commonstock was $17.59 per share. Investing in our securities involves a high degree of risk. See “Risk Factors” beginning on page S-8 of thisprospectus supplement and page 6 of the accompanying prospectus, as well as in the documents incorporated byreference herein and therein, to read about factors you should consider before buying our securities. Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities ordetermined if this prospectus supplement or the accompanying prospectus is truthful or complete. Any representation to the contrary is acriminal offense. We have granted the underwriters an option for a period of 30 days to purchase up to an additional 1,500,000 shares of our common stock from us at thepublic offering price, less underwriting discounts and commissions. If the underwriters exercise the option in full, the total underwriting discounts andcommissions payable by us will be $10,350,000 and the total proceeds to us, before expenses, will be $162,150,000. Delivery of the shares of common stock is expected to be made on or about June5, 2026. Joint Book-Running Managers TDCowen Jefferies UBSInvestmentBank LifeSciCapital Lead Manager BTIG Prospectus Supplement dated June3, 2026 Table of Contents TABLE OF CONTENTS Prospectus Supplement ABOUT THIS PROSPECTUS SUPPLEMENTPROSPECTUS SUPPLEMENT SUMMARYTHE OFFERINGRISK FACTORSCAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTSUSE OF PROCEEDSDILUTIONMATERIAL U.S. FEDERAL INCOME TAX CONSEQUENCES TO NON-U.S. HOLDERSUNDERWRITINGLEGAL MATTERSEXPERTSWHERE YOU CAN FIND MORE INFORMATION; INCORPORATION BY REFERENCE Prospectus Table of Contents ABOUT THIS PROSPECTUS SUPPLEMENT This prospectus supplement and the accompanying prospectus dated May15, 2026 are part of a registration statement on Form S-3 that we filedwith the Securities and Exchange Commission (the “SEC”), utilizing a “shelf” registration process. This prospectus supplement and the accompanyingprospectus relate to the offer by us of shares of our common stock. We provide information to you about this offering of shares of our common stock intwo separate documents that are bound together: (1)this prospectus supplement, which describes the specific details regarding this offering; and (2)theaccompanying prospectus, which provides general information, some of which may not apply to this offering. Generally, when we refer to this“prospectus,” we are referring to both documents combined. If information in this prospectus supplement is inconsistent with the accompanyingprospectus, you should rely on this prospectus supplement. However, if any statement in one of these documents is inconsistent with a statement inanother document having a later date—for example, a document incorporated by reference in this prospectus supplement or the accompanyingprospectus—the statement in the document having the later date modifies or supersedes the earlier statement as our business, financial condition, resultsof operations and prospects may have changed since the earlier dates. You should read this prospectus supplement, the accompanying prospectus and thedocuments and information incorporated by reference in this prospectus supplement and the accompanying prospectus that we have authorized for use inconnection with this offering when making your investment decision. You should also read and consider the information in the documents we havereferred you to under the headings “Where You Can Find More Information; Incorporation by Reference.” You should rely only on information contained in or incorporated by reference into this prospectus supplement and the accompanying prospectusprepared by or on behalf of us or to which we have referred you. We have not, and the underwriters have not, authorized anyone to provide you withinformation that is different. We are offering to sell and seeking offers to buy shares of our common stock only in jurisdictions where offers and sales arepermitted. The information contained in this prospectus supplement, the accompanying prospectus and the documents and information incorporated byreference in this prospectus supplement and the accompanying prospectus that we have authorized for use in connection with this offering are accurateonly as of their respective dates, regardless of the time of delivery of this prospectus supplement or of any sale of our common stock. When we refer to “Jade,” “we,” “our,” “us” and the “Company” in this prospectus supplement, we mean Jade Biosciences, Inc. and itssubsidiaries, unless otherwise specified. When we refer to “you,” we mean the holders of the applicable series of securities. We use our tra