螺栓项目控股有限公司美股招股说明书（2025-09-16版）

Prospectus Supplement No. 8(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 September15, 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 Prospectus orthis prospectus supplement is truthful or complete. Any representation to the contrary is a criminal offense. The date of this prospectus supplement is September 16, 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 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)) Securities registered pursuant to Section 12(b) of the Act: 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). 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 1.01. Entry into a Material Definitive Agreement. Equity Purchase Agreement On September 12, 2025, Bolt Projects Holdings, Inc. (the “Company”) entered into an equity purchase agreement (the “PurchaseAgreement”) with Ascent Partners Fund LLC, a Delaware limited liability company (the “Investor”) relating to an equity line of creditfacility (the “ELOC”). Pursuant to the Purchase Agreement, the Company will have the right from time to time at its option to sell tothe Investor up to $20.0 million of the Company’s common stock, par value $0.0001 per share (“Common Stock”), subject to certaincustomary conditions and limitations set forth in the Purchase Agreement, including that (i) the Investor shall not be obligated topurchase or acquire any shares of Common Stock that would result in its beneficial ownership exceeding 9.99% of the Company’sthen-outstanding voting power and (ii) the Investor shall not be obligated to purchase shares of Common Stock if the volume weightedaverage price for the Common Stock on an Advance Notice Date (as defined in the Purchase Agreement) is less than $1.00 (the “FloorPrice”). Pursuant to the Purchase Agreement, the Company will have the right, but not the obligation, to direct the Investor to purchase sharesof Common Stock at its sole discretion from time to time until the earlier of (i) the first day of the month following the 36-monthperiod after the effective date of a registration statement registering the resale of the Common Stock sold to the Investor pursuant tothe Purchase Agreement and (ii) $20.0 million of Common Stock have been sold to the Investor pursuant to the Purchase Agreement.To initiate a purchase, the Company must deliver written notice to the Investor before trading begins on any trading day. The purchaseprice of the shares (the “Share Price”) will be determined based on the timing and conditions of an advance notice (each, an “AdvanceNotice”). If an Advance Notice is received before 8:01 a.m. Eastern Time on a trading day and the amount is between $25,000 and$500,000, the price will be 96% of the lowest volume-weighted ave