BridgeBio Oncology Therapeutics Inc美股招股说明书(2026-08-12版)

BridgeBio Oncology Therapeutics, Inc.63,054,549 Shares of Common Stock by the Selling Securityholders This prospectus supplement no. 9 (this “Prospectus Supplement”) amends and supplements the prospectus dated September 10,2025 (as may be supplemented or amended from time to time, the “Prospectus”), which forms part of our Registration Statement onForm S-1 (Registration Statement No. 333-289940), as amended by the Post-Effective Amendment No. 1 thereto (RegistrationStatement No. 333-289940). This Prospectus Supplement is being filed to update and supplement the information included orincorporated by reference in the Prospectus with the information contained in the attached Quarterly Report on Form 10-Q, filedwith the Securities and Exchange Commission (the “Securities and Exchange Commission”) on August 11, 2026 (the “Form 10-Q”).Accordingly, we have attached the Form 10-Q to this Prospectus Supplement. This Prospectus Supplement updates and supplements the information in the Prospectus and is not complete without, and maynot be delivered or utilized except in combination with, the Prospectus, including any amendments or supplements thereto. ThisProspectus Supplement should be read in conjunction with the Prospectus, and if there is any inconsistency between the informationin the Prospectus and this Prospectus Supplement, you should rely on this Prospectus Supplement. Our common stock, par value $0.0001 per share (“Common Stock”) is listed on Nasdaq Global Market (“Nasdaq”) under thesymbol “BBOT”. On August 11, 2026, the closing price of our Common Stock as reported on Nasdaq was $9.20 per share. We are an “emerging growth company” as that term is defined under the federal securities laws and, as such, are subjectto certain reduced public company reporting requirements. Investing in our securities involves risks that are described in the “Risk Factors” section beginning on page 10 of theProspectus. Neither the SEC nor any state securities commission has approved or disapproved of the securities to be issued underthis prospectus or determined if this prospectus is truthful or complete. Any representation to the contrary is a criminaloffense. UNITED STATESSECURITIES AND EXCHANGE COMMISSIONWashington, D.C. 20549 (Mark One)☒QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended June 30, 2026 OR ☐TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934For the transition period fromtoCommission File Number: 001-41955 BRIDGEBIO ONCOLOGY THERAPEUTICS, INC. (Exact name of Registrant as specified in its Charter) Delaware(State or other jurisdiction ofincorporation or organization)256 E. Grand Avenue, Suite 104South San Francisco, CA(Address of principal executive offices) Registrant’s telephone number, including area code: (650) 405-4770 Securities registered pursuant to Section 12(b) of the Act: Indicate by check mark whether the Registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities ExchangeAct of 1934 during the preceding 12 months (or for such shorter period that the Registrant was required to file such reports), and (2) has beensubject to such filing requirements for the past 90 days.Yes☒No☐ Indicate by check mark whether the Registrant has submitted electronically every Interactive Data File required to be submitted pursuant toRule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the Registrant was requiredto submit such files).Yes☒No☐ Indicate by check mark whether the Registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, smaller reportingcompany, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and“emerging growth company” in Rule 12b-2 of the Exchange Act. Large accelerated filer☐Non-accelerated filer☒Emerging growth company☒ Accelerated filer☐Smaller reporting company☒ If an emerging growth company, indicate by check mark if the Registrant has elected not to use the extended transition period for complyingwith any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act.☐ Indicate by check mark whether the Registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act).Yes☐No☒ As of August 6, 2026, the registrant had 80,174,267 shares of common stock, $0.0001 par value per share, outstanding. Table of Contents PART I.FINANCIAL INFORMATION Item 1.Financial Statements(unaudited)Condensed Consolidated Balance SheetsCondensed Consolidated Statements of OperationsCondensed Consolidated Statements of Comprehensive LossCondensed Consolidated Statements of Redeemable Convertible Preferred Stock and Stockholders' Equity(Deficit)Condensed Consolidated Statements of Cash FlowsNotes to Condensed Consolidated Financial Stat