Abpro Holdings Inc美股招股说明书(2025-11-17版)

PROSPECTUS SUPPLEMENT NO. 4(to Prospectus dated May 5, 2025) ABPRO HOLDINGS, INC. This prospectus supplement supplements the prospectus dated May 5, 2025 (the “Prospectus”), which forms a part of ourregistration statement on Form S-1 (No. 333-284021). Capitalized terms used in this prospectus supplement and not otherwise defined This prospectus supplement is being filed to update and supplement the information in the Prospectus with the informationcontained in our Quarterly Report on Form 10-Q for the fiscal quarter ended September 30, 2025, filed with the Securities and Our shares of Common Stock and Public Warrants are currently listed on the Nasdaq Global Market (“Nasdaq”) under thesymbols “ABP” and “ABPW,” respectively. On November 14, 2025, the closing price of our Common Stock was $5.49 per share and This prospectus supplement updates and supplements the information in the Prospectus and is not complete without, and may notbe 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 information in Investing in our securities involves a high degree of risk. You should review carefully the risks and uncertainties describedin the section titled “Risk Factors” beginning on page 7 of the Prospectus, and under similar headings in any amendments orsupplements to the Prospectus. Neither the Securities and Exchange Commission nor any state securities commission has The date of this prospectus supplement is November 17, 2025 Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the SecuritiesExchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submittedpursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the Indicate by check mark whether the registrant is a large, accelerated filer, an accelerated filer, a non-accelerated filer, a smallerreporting company or an emerging growth company. See definitions of “large, accelerated filer”, “accelerated filer”, “smaller reporting 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.☐ 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 November 14, 2025, there were 2,716,278 shares of common stock, par value $0.0001 per share, issued and outstanding. TABLE OF CONTENTS PART I - FINANCIAL INFORMATION ABPRO HOLDINGS, INC.CONDENSED CONSOLIDATED BALANCE SHEETS(in thousands except for share and per share data) Commitments and Contingencies (Note 8) Stockholders' deficit: Preferred stock, $0.0001 par value, 1,000,000 shares authorized; zero shares issued and outstanding--Common stock, $0.0001 par value; 110,000,000 shares authorized; 2,672,222 and 1,727,192 sharesissued, 2,672,222 and 1,694,414 shares outstanding at September 30, 2025 and December 31, 2024,respectively--Treasury stock, zero and 32,778 shares at September 30, 2025 and December 31, 2024, respectively, atcost--Additional paid-in capital108,487100,608Accumulated deficit(124,631)(116,103) ABPRO HOLDINGS, INC.NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS 1.Organization and Description of the Business Organization Abpro Holdings, Inc. and its subsidiaries, (the “Company”) is a biotechnology company dedicated to developing next-generationantibody therapeutics to improve the lives of patients with severe and life-threatening diseases. The Company is focused on the On November 13, 2024 (the “Closing Date”), Atlantic Coastal Acquisition Corp. II (“ACAB”) consummated a merger (the “Merger”)pursuant to the terms of the Merger Agreement, dated as of December 11, 2023 (the “Merger Agreement”) by and among AbproCorporation (“Legacy Abpro”), ACAB, and Abpro Merger Sub Corp., a Delaware corporation (“Merger Sub”) and wholly ownedsubsidiary of ACAB prior to the Closing Date. Pursuant to the Merger Agreement, on the Closing Date, (i) ACAB changed its name to“Abpro Holdings, Inc.” (“New Abpro”), and (ii)Merger Sub merged with and into Legacy Abpro, with Legacy Abpro as the surviving After giving effect to the Merger, Legacy Abpro became a wholly owned subsidiary of the Company. The Merger was accounted for asa reverse recapitalization in accordance with U.S. GAAP, and under this method of accounting, ACAB was treated as the acquiredcompany for financial reporting purposes and Legacy Abpro was treated as the acquirer. Oper