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): November 12, 2026

GP-Act III Acquisition Corp.

(Exact name of registrant as specified in its charter)

+1 (212) 430-4340

(Registrant’s telephone number, including area code)

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 registrant under any of the following provisions:

Securities registered pursuant to Section 12(b) of the Securities Exchange Act of 1934:

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§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 1.01 Entry into a Material Definitive Agreement.

Non-Redemption Agreements

As previously disclosed in a Current Report on Form 8-K filed by GP-Act III Acquisition Corp., a Cayman Islands exempted company (the “Company”), with the U.S. Securities and Exchange Commission (the “SEC”) on November 10, 2026, the Company and GP-Act III Sponsor LLC, a Cayman Islands limited liability company and the Company’s sponsor (“Sponsor HoldCo”), entered into agreements (collectively, the “Non-Redemption Agreements”) with one or more third-party shareholders of the Company (each, an “Investor”) in exchange for such Investors agreeing (i) not to redeem (or to validly rescind any redemption requests previously made in respect of) an aggregate of 2,525,000 of the Company’s Class A ordinary shares, par value $0.0001 per share (the “Class A ordinary shares”), included in the units sold in the Company’s initial public offering (such shares subject to the Non-Redemption Agreements, the “Non-Redeemed Shares”), in connection with the Extraordinary General Meeting (as defined below), and (ii) to vote (in person or by proxy), or provide consent with respect to, all Non-Redeemed Shares owned by such Investors as of the record date in favor of the Extension Amendment Proposal and the Trust Amendment Proposal (each as defined below) at the Extraordinary General Meeting.

Pursuant to the Non-Redemption Agreements, Sponsor HoldCo has agreed to transfer to such Investors an aggregate of 505,000 existing Class A ordinary shares held by Sponsor HoldCo that were issued upon the conversion of its Class B ordinary shares promptly following the closing of the Company’s initial business combination, conditional on, among other matters, (i) such Investors not exercising (or having validly rescinded any prior exercise of) their redemption rights with respect to the Non-Redeemed Shares in connection with the Extraordinary General Meeting, (ii) such Investors voting or consenting in favor of the Extension Amendment and the Trust Amendment at the Extraordinary General Meeting and (iii) the Extension Amendment and the Trust Amendment being approved at the Extraordinary General Meeting.

As previously disclosed, on November 3, 2026, the Company entered into a Business Combination Agreement (the “Business Combination Agreement”) with Dronamics Group Limited (“Dronamics”). The Business Combination Agreement permits the Company, Sponsor HoldCo and their respective affiliates to enter into non-redemption agreements in connection with an extension of the deadline by which the Company must consummate its initial business combination, provided that any consideration payable thereunder is borne solely by Sponsor HoldCo. No funds in the Company’s trust account will be used to pay any consideration under the Non-Redemption Agreements.

The foregoing summary of the Non-Redemption Agreements does not purport to be complete and is qualified in its entirety by reference to the form of Non-Redemption Agreement, a copy of which was filed as Exhibit 10.1 to the Company’s Current Report on 8-K filed with the SEC on November 12, 2026 and is incorporated herein by reference.

Trust Amendment

On November 12, 2026, in connection with the Extraordinary General Meeting, the Company and Continental Stock Transfer & Trust Company (the “Trustee”), entered into Amendment No. 2 to the Investment Management Trust Agreement, dated as of May 8, 2024, as amended by Amendment No. 1 thereto as of May 12, 2026, by and between the Company and the Trustee (as so amended, the “Trust Agreement”), to extend the date on which the Trustee must liquidate the trust account established in connection with the Company’s initial public offering (the “Trust Account”) if the Company has not completed its initial business combination from November 13, 2026 to May 8, 2027 (the “Trust Amendment”). A copy of the Trust Amendment is attached to this Current Report on Form 8-K as Exhibit 10.1 and incorporated herein by reference.

Item 5.03 Amendments to Articles of Incorporation or Bylaws; Change in Fiscal Year.

The information disclosed in Item 5.07 of this Current Report on Form 8-K is incorporated by reference into this Item 5.03 to the extent required herein.

Item 5.07 Submission of Matters to a Vote of Security Holders.

On November 12, 2026 at 9:00 a.m., Eastern Time, the Company convened its extraordinary general meeting of shareholders (the “Extraordinary General Meeting”) and, following the approval by the shareholders of the Company , adjourned the Extraordinary General Meeting to 1:00 p.m., Eastern Time, on November 12, 2026. The Extraordinary General Meeting was reconvened at 1:00 p.m., Eastern Time, on November 12, 2026. At the Extraordinary General Meeting, holders of 15,141,122 of the Company’s ordinary shares, representing approximately 93.69% of the 16,161,228 ordinary shares issued and outstanding and entitled to vote as of the record date of October 14, 2026, were represented in person (including virtually) or by proxy, constituting a quorum.

At the Extraordinary General Meeting, the shareholders approved (1) a special resolution to amend the Amended and Restated Memorandum and Articles of Association of the Company (the “Extension Amendment”) to extend the date by which the Company must (a) consummate a merger, amalgamation, share exchange, asset acquisition, share purchase, reorganization or similar business combination with one or more businesses (a “business combination”), (b) cease its operations except for the purpose of winding up if it fails to complete such business combination, and (c) redeem all of the Company’s Class A ordinary shares included as part of the units sold in the Company’s initial public offering, from November 13, 2026 to May 8, 2027, and (2) the proposals for the Trust Amendment. A copy of the Extension Amendment is attached to this Current Report on Form 8-K as Exhibit 3.1 and incorporated herein by reference.

Extension Amendment Proposal

Trust Amendment Proposal

Adjournment Proposal

In connection with the vote to approve the Extension Amendment Proposal, the holders of 6,266,194 Class A ordinary shares properly exercised their right to redeem their shares for cash at a redemption price of approximately $11.10 per share, for an aggregate redemption amount of approximately $69,528,380.68, leaving approximately $30,042,232.15 in the Trust Account following the payment of such redemptions.

The information included in Item 1.01 of this Current Report on Form 8-K is incorporated by reference into this Item 5.07 to the extent required herein.

Additional Information

Important Information About the Extension, the Proposed Business Combination and Where to Find It

The Company filed the Definitive Proxy Statement for the Extraordinary General Meeting with the SEC on October 26, 2026 to consider and vote upon, among other things, the Extension Amendment Proposal and the Trust Amendment Proposal, and, beginning on or about October 26, 2026, first mailed the Proxy Statement and other relevant documents to its shareholders as of the October 14, 2026 record date for the Extraordinary General Meeting. BEFORE MAKING ANY VOTING DECISION WITH RESPECT TO THE EXTRAORDINARY GENERAL MEETING, THE COMPANY’S SHAREHOLDERS AND OTHER INTERESTED PERSONS WERE URGED TO READ THE DEFINITIVE PROXY STATEMENT AND ANY AMENDMENTS AND SUPPLEMENTS THERETO, AS WELL AS ALL OTHER RELEVANT DOCUMENTS FILED OR THAT WILL BE FILED WITH THE SEC IN CONNECTION WITH THE COMPANY’S SOLICITATION OF PROXIES FOR THE EXTRAORDINARY GENERAL MEETING HELD ON NOVEMBER 12, 2026 TO APPROVE, AMONG OTHER THINGS, THE EXTENSION AMENDMENT PROPOSAL AND THE TRUST AMENDMENT PROPOSAL, BECAUSE THESE DOCUMENTS CONTAIN IMPORTANT INFORMATION ABOUT THE COMPANY, THE EXTENSION AMENDMENT PROPOSAL AND THE TRUST AMENDMENT PROPOSAL. The Definitive Proxy Statement does not solicit, and shareholders were not being asked at the Extraordinary General Meeting to vote on, the approval of the proposed business combination with Dronamics. Shareholders may also obtain a copy of the Definitive Proxy Statement, as well as other documents filed with the SEC by the Company, without charge, at the SEC’s website located at www.sec.gov or by directing a request to the Company’s proxy solicitor, Sodali & Co., GPAT.info@investor.sodali.com.

The proposed business combination with Dronamics will be submitted to shareholders of the Company for their consideration at a separate extraordinary general meeting. The Company and Dronamics intend to file with the SEC a registration statement on Form S-4 (as may be amended, the “Registration Statement”), which will include a preliminary proxy statement to be distributed to the Company’s shareholders in connection with the Company’s solicitation of proxies for the vote by the Company’s shareholders in connection with the proposed business combination and other matters as described in the Registration Statement, as well as the prospectus relating to the offer of the securities to be issued in connection with the completion of the proposed business combination (the “proxy statement / prospectus”). As of the date hereof, the Registration Statement has not been filed with the SEC. After the Registration Statement has been filed and declared effective, the Company will mail a definitive proxy statement / prospectus and other relevant documents to its shareholders as of the record date established for voting on the proposed business combination. BEFORE MAKING ANY VOTING OR INVESTMENT DECISION WITH RESPECT TO THE PROPOSED BUSINESS COMBINATION, SHAREHOLDERS OF THE COMPANY AND OTHER INTERESTED PARTIES ARE URGED TO READ, WHEN AVAILABLE, THE PRELIMINARY PROXY STATEMENT / PROSPECTUS, AND AMENDMENTS THERETO, AND THE DEFINITIVE PROXY STATEMENT / PROSPECTUS AND ALL OTHER RELEVANT DOCUMENTS FILED OR THAT WILL BE FILED WITH THE SEC IN CONNECTION WITH THE COMPANY’S SOLICITATION OF PROXIES FOR THE EXTRAORDINARY GENERAL MEETING OF ITS SHAREHOLDERS TO BE HELD TO APPROVE THE PROPOSED BUSINESS COMBINATION AND OTHER MATTERS AS DESCRIBED IN THE PROXY STATEMENT / PROSPECTUS, BECAUSE THESE DOCUMENTS WILL CONTAIN IMPORTANT INFORMATION ABOUT THE COMPANY, DRONAMICS AND THE PROPOSED BUSINESS COMBINATION. The Company and Dronamics may also file other documents regarding the proposed business combination with the SEC. Shareholders may also obtain copies of these documents, once available, without charge, at the SEC’s website located at www.sec.gov or by directing a request to: GP-Act III Acquisition Corp., 300 Park Avenue, 2nd Floor, New York, New York 10022.

NEITHER THE SEC NOR ANY STATE SECURITIES REGULATORY AGENCY HAS APPROVED OR DISAPPROVED THE PROPOSED BUSINESS COMBINATION OR ANY RELATED TRANSACTIONS DESCRIBED HEREIN, PASSED UPON THE MERITS OR FAIRNESS OF THE PROPOSED BUSINESS COMBINATION OR ANY RELATED TRANSACTIONS OR PASSED UPON THE ADEQUACY OR ACCURACY OF THE DISCLOSURE IN THIS CURRENT REPORT ON FORM 8-K. ANY REPRESENTATION TO THE CONTRARY CONSTITUTES A CRIMINAL OFFENSE.

Participants in the Solicitation

The Company, Sponsor HoldCo and certain of the Company’s directors, executive officers and other members of management and employees may, under SEC rules, be deemed to be participants in the solicitation of proxies from the Company’s shareholders in connection with the Extraordinary General Meeting. Information regarding such persons and their interests in the Extension Amendment Proposal and the Trust Amendment Proposal, which may be different from or in addition to those of the Company’s shareholders generally, is set forth in the Proxy Statement, including under “The Extraordinary General Meeting — Interests of Sponsor HoldCo, our Co-Sponsors, Directors and Officers,” and in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2025, filed with the SEC on March 26, 2026 (the “Annual Report”).

Furthermore, the Company, Dronamics and certain of their respective directors, executive officers and other members of management, employees and consultants may, under SEC rules, be deemed to be participants in the solicitation of proxies from the Company’s shareholders in connection with the proposed business combination. Information regarding such persons and their interests will be set forth in the proxy statement / prospectus when it is filed with the SEC. You can find more information about the Company’s directors and executive officers in the Annual Report. Shareholders, potential investors and other interested persons should read the Registration Statement and, when available, the proxy statement / prospectus carefully before making any voting or investment decisions. You may obtain free copies of these documents from the sources indicated above.

Forward-Looking Statements

The information included herein and in any oral statements made in connection herewith includes “forward-looking statements.” Forward-looking statements may be identified by the use of words such as “estimate,” “plan,” “project,” “forecast,” “intend,” “will,” “expect,” “anticipate,” “believe,” “seek,” “target” or other similar expressions that predict or indicate future events or trends or that are not statements of historical matters, although not all forward-looking statements contain such identifying words. These forward-looking statements include, but are not limited to, statements regarding the approval of the Extension Amendment Proposal and the Trust Amendment Proposal, the expected benefits of the Non-Redemption Agreements, the consummation of the proposed business combination with Dronamics and the funds that will remain in the trust account following redemptions. These forward-looking statements are provided for illustrative purposes only and are not intended to serve as, and must not be relied on by any investor as, a guarantee, an assurance, a prediction or a definitive statement of fact or probability. Actual events and circumstances are difficult or impossible to predict and will differ from assumptions. Many actual events and circumstances are beyond the control of the Company. These forward-looking statements are subject to a number of risks and uncertainties, including changes in domestic and foreign business, market, financial, political and legal conditions; the inability of the Company to successfully or timely implement the Extension Amendment Proposal and the Trust Amendment Proposal; the occurrence of any event, change or other circumstances that could give rise to the termination of the Business Combination Agreement; the risk that the proposed business combination may not be completed in a timely manner or at all, including by the Company’s business combination deadline, including due to the failure to satisfy the conditions to closing, including the approval of the Company’s shareholders; and those factors described or referenced in the Company’s filings with the SEC, including under the heading “Risk Factors” in the Proxy Statement and the Annual Report, and, when available, the Registration Statement. If any of these risks materialize or assumptions prove incorrect, actual results could differ materially from the results implied by these forward-looking statements. There may be additional risks that the Company presently knows or that the Company currently believes are immaterial that could also cause actual results to differ from those contained in the forward-looking statements. In addition, forward-looking statements reflect the Company’s expectations, plans or forecasts of future events and views as of the date hereof. The Company anticipates that subsequent events and developments will cause the Company’s assessments to change. However, while the Company may elect to update these forward-looking statements at some point in the future, the Company specifically disclaims any obligation to do so except as otherwise required by applicable law. These forward-looking statements should not be relied upon as representing the Company’s assessments as of any date subsequent to the date hereof. Accordingly, undue reliance should not be placed upon the forward-looking statements.

No Offer or Solicitation

This Current Report on Form 8-K is for informational purposes only and shall not constitute an offer to sell, nor a solicitation of an offer to buy, any securities in connection with the Extension Amendment Proposal, the Trust Amendment Proposal, the proposed business combination or otherwise, or the solicitation of a proxy, consent or authorization in any jurisdiction pursuant to or in connection with the Extension Amendment Proposal, the Trust Amendment Proposal, the proposed business combination or otherwise, nor shall there be any sale of securities in any jurisdiction in which the offer, solicitation or sale would be unlawful prior to the registration or qualification under the securities laws of any such jurisdiction or otherwise in contravention of applicable law. No offer of securities shall be made except by means of a prospectus meeting the requirements of Section 10 of the Securities Act of 1933, as amended, or an exemption therefrom, and otherwise in accordance with applicable law.

Item 9.01 Financial Statements and Exhibits

(d) Exhibits

* Certain schedules and similar attachments have been omitted in reliance on Instruction 4 Item 1.01 of Form 8-K.

SIGNATURE

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

ATTACHMENTS / EXHIBITS

AMENDMENTS TO THE AMENDED AND RESTATED MEMORANDUM AND ARTICLES OF ASSOCIATION OF GP-ACT III ACQUISITION CORP., EFFECTIVE NOVEMBER 12, 2026

AMENDMENT NO. 2, DATED AS OF NOVEMBER 12, 2026, TO THE INVESTMENT MANAGEMENT TRUST AGREEMENT, DATED AS OF MAY 8, 2024, AS AMENDED ON MAY 12, 2026, BY AND BETWEEN THE COMPANY AND CONTINENTAL STOCK TRANSFER & TRUST COMPANY, AS TRUSTEE