SEC Form 424B3 filed by Bolt Projects Holdings Inc.

Filed pursuant to Rule 424(b)(3)

Registration Statement No. 333-284964

Prospectus Supplement No. 3

(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 a part of our Registration Statement on Form S-1 (Registration No. 333-284964). Capitalized terms used in this prospectus supplement and 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 the information contained in our Current Report on Form 8-K, filed with the Securities and Exchange Commission (“SEC”) on July 14, 2025, which is set forth below.

This prospectus supplement is not complete without the Prospectus. This prospectus supplement should be read in conjunction with the Prospectus, which is to be delivered with this prospectus supplement, and is qualified by reference thereto, except to the extent that the information in this prospectus supplement updates or supersedes the information contained in the Prospectus. Please keep this prospectus supplement with your Prospectus for future reference.

INVESTING IN OUR SECURITIES INVOLVES CERTAIN RISKS. SEE “RISK FACTORS” BEGINNING ON PAGE 7 OF THE PROSPECTUS.

Neither the SEC nor any state securities commission has approved or disapproved of these securities or determined if the Prospectus or this prospectus supplement is truthful or complete. Any representation to the contrary is a criminal offense.

The date of this prospectus supplement is July 15, 2025

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

PURSUANT TO SECTION 13 OR 15(d)

OF THE SECURITIES EXCHANGE ACT OF 1934

Date of Report (Date of earliest event reported): July 11, 2025

Bolt Projects Holdings, Inc.

(Exact name of registrant as specified in its charter)

(415) 325-5912

(Registrant’s telephone number, including area code)

N/A

(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 registrant under any of the following provisions:

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).

Emerging growth company ☒

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Item 5.02 Departure of Directors or Principal Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers.

On July 11, 2025, the Board of Directors (the “Board”) of Bolt Projects Holdings, Inc. (the “Company”) appointed Lorne Lucree and Gail Zauder to the Board to serve as Class II and Class III directors, respectively, effective as of that date. Mr. Lucree will serve for a term expiring at the Company’s annual meeting of stockholders to be held in 2026, and Ms. Zauder will serve for a term expiring at the Company’s annual meeting of stockholders to be held in 2027, in each case, until their respective successor is duly elected and qualified or until their earlier death, resignation, disqualification or removal.

In connection with Mr. Lucree’s and Ms. Zauder’s appointment to the Board, each became eligible to participate in, and receive cash and equity compensation pursuant to the terms and conditions of, the Company’s Non-Employee Director Compensation Program filed as Exhibit 10.15 to the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2024 (the “Form 10-K”). The material terms of the Company’s Non-Employee Director Compensation Program are described in the Form 10-K under Part III, Item 11. “Executive Compensation — Narrative to Summary Compensation Table — Executive Compensation Arrangements — Director Compensation Program” and are incorporated by reference herein.

Each of Mr. Lucree and Ms. Zauder is expected to enter into the Company’s standard form indemnification agreement in the form filed as Exhibit 10.28 to the Company’s Registration Statement on Form S-4/A (File No. 333-276849) filed with the Securities and Exchange Commission on July 10, 2024.

SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

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