螺栓项目控股有限公司美股招股说明书（2025-10-03版）

Prospectus Supplement No. 9(To Prospectus dated March 27, 2025) BOLT PROJECTS HOLDINGS, INC. This prospectus supplement updates, amends and supplements the prospectus dated March 27, 2025 (the “Prospectus”), which forms apart of our Registration Statement on Form S-1 (Registration No. 333-284964). Capitalized terms used in this prospectus supplementand not otherwise defined herein have the meanings specified in the Prospectus. This prospectus supplement is being filed to update, amend and supplement the information included in the Prospectus with theinformation contained in our Current Report on Form 8-K, filed with the Securities and Exchange Commission (“SEC”) on October 2,2025, which is set forth below. This prospectus supplement is not complete without the Prospectus. This prospectus supplement should be read in conjunction withthe Prospectus, which is to be delivered with this prospectus supplement, and is qualified by reference thereto, except to the extent thatthe information in this prospectus supplement updates or supersedes the information contained in the Prospectus. Please keep thisprospectus supplement with your Prospectus for future reference. INVESTING IN OUR SECURITIES INVOLVES CERTAIN RISKS. SEE “RISK FACTORS” BEGINNING ON PAGE 7 OF THEPROSPECTUS. Neither the SEC nor any state securities commission has approved or disapproved of these securities or determined if the Prospectusor this prospectus supplement is truthful or complete. Any representation to the contrary is a criminal offense. The date of this prospectus supplement is October 3, 2025 UNITED STATESSECURITIES AND EXCHANGE COMMISSIONWashington, D.C. 20549 FORM 8-K CURRENT REPORTPURSUANT TO SECTION 13 OR 15(d)OF THE SECURITIES EXCHANGE ACT OF 1934 Date of Report (Date of earliest event reported): September 30, 2025 Not Applicable(Former name or former address, if changed since last report) Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrantunder any of the following provisions: Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c)) Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933(Sec.230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (Sec.240.12b-2 of this chapter). Emerging growth company☒ If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period forcomplying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act.☐ Item 3.01 Notice of Delisting or Failure to Satisfy a Continued Listing Rule or Standard;Transfer of Listing. As previously reported, on August 12, 2025, Bolt Projects Holdings, Inc. (the “Company”) received a letter from the Nasdaq StockMarket (“Nasdaq”) stating that, as a result of the Company’s continued non-compliance with the minimum market value of listedsecurities requirement as set forth in Nasdaq Listing Rule 5450(b)(2)(A) (“MVLS”) and with the minimum market value of publiclyheld shares requirement as set forth in Nasdaq Listing Rule 5450(b)(2)(C) (“MVPHS”), its securities would be delisted from Nasdaqunless the Company appeals the delisting determination by requesting a hearing before the Nasdaq Hearings Panel (the “Panel”). TheCompany made a timely request for a hearing before the Panel to appeal the delisting determination. On September 30, 2025, the Company received written notification from the Panel (the “Determination Letter”) granting theCompany’s request for an extension to regain compliance with Nasdaq’s listing standards based on the compliance plan presented atthe Company’s hearing before the Panel. As part of that plan, the Company presented a timeline of achieving compliance byDecember 31, 2025, which date is within the Panel’s authority under Nasdaq Listing Rule 5815 to grant an extension of up to 180days. Pursuant to the Determination Letter, the Company is to gain compliance with the minimum equity standard requirement underNasdaq Listing Rule 5550(b)(1) (the “Equity Rule”) in lieu of regaining compliance with Nasdaq’s MVLS and MVPHS listing rulesand is to phase down to the Nasdaq Capital Market. The Company intends to satisfy these requirements and demonstrate compliancewith the Equity Rule within the current extension period or, if appropriate, to request a further extension from the Panel, with any suchfurther extension subject to the Panel’s discretion. The Company is undertaking measures to regain compliance within the extension period, however, there