Plum Acquisition Corp. IV

Item 7.01. Regulation FD Disclosure. On October 1, 2026, Plum Acquisition Corp. IV (“Plum IV”) and Controlled Thermal Resources Holdings Inc. (“CTR”) issued a joint press release announcing that, in connection with the parties’ previously announced business combination, CTR had entered into a series of agreements with certain strategic investors that are expected to materially strengthen CTR’s capital structure. A copy of the press release is attached as Exhibit 99.1 to this Current Report on Form 8-K (“Current Report”). The information in this Item 7.01, including Exhibit 99.1, is furnished and shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to liabilities under that section, and shall not be deemed to be incorporated by reference into the filings of Plum IV under the Securities Act of 1933, as amended, or the Exchange Act, regardless of any general incorporation language in such filings. Additional Information and Where to Find It In connection with the transactions contemplated by the business combination agreement (“Proposed Transactions”), Plum IV and CTR intend to file with the U.S. Securities and Exchange Commission (“SEC”) a registration statement on Form S-4 (as may be amended, the “Registration Statement”), which will include a preliminary proxy statement of Plum IV as well as a preliminary prospectus relating to the offer of securities to be issued to the stockholders of CTR (the “Proxy Statement/Prospectus”). After the Registration Statement is declared effective, a definitive proxy statement and other relevant documents will be mailed to shareholders of Plum IV as of the record date to be established for voting on the Proposed Transactions and other matters as described in the Proxy Statement/Prospectus. Plum IV will also file other documents regarding the Proposed Transactions with the SEC. This Current Report does not contain all of the information that should be considered concerning the Proposed Transactions and is not intended to form the basis of any investment decision or any other decision in respect of the Proposed Transactions. BEFORE MAKING ANY VOTING OR INVESTMENT DECISION, SHAREHOLDERS OF PLUM IV 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 PLUM IV’S SOLICITATION OF PROXIES FOR THE EXTRAORDINARY GENERAL MEETING OF ITS SHAREHOLDERS TO BE HELD TO APPROVE THE PROPOSED TRANSACTIONS AND OTHER MATTERS AS DESCRIBED IN THE PROXY STATEMENT/PROSPECTUS BECAUSE THESE DOCUMENTS WILL CONTAIN IMPORTANT INFORMATION ABOUT PLUM IV, CTR AND THE PROPOSED TRANSACTIONS. Investors and security holders will also be able to obtain copies of the Registration Statement and the Proxy Statement/Prospectus and all other documents filed or to be filed with the SEC by Plum IV, without charge, once available, on the SEC’s website at www.sec.gov or by directing a request to: Plum Acquisition Corp. IV, 2021 Fillmore St., #2089, San Francisco, California 94115, Attention: Kanishka Roy, or by email at plumir@icrinc.com. Participants in the Solicitation Plum IV, CTR and their respective directors and executive officers may be deemed participants under SEC rules in the solicitation of proxies from Plum IV’s shareholders in connection with the Proposed Transactions. A list of the names of such directors and executive officers, and information regarding their interests in the Proposed Transactions and their ownership of Plum IV’s securities is, or will be, contained in Plum IV’s filings with the SEC. Additional information regarding the interests of the persons who may, under SEC rules, be deemed participants in the solicitation of proxies from Plum IV’s shareholders in connection with the Proposed Transactions, including the names and interests of CTR’s directors and executive officers, will be set forth in the Proxy Statement/Prospectus, which is expected to be filed by Plum IV and CTR with the SEC. Investors and security holders may obtain free copies of these documents as described above. 1 No Offer or Solicitation This Current Report is for informational purposes only and is not a proxy statement or solicitation of a proxy, consent or authorization with respect to any securities or in respect of the Proposed Transactions and shall not constitute an offer to sell or exchange, or a solicitation of an offer to buy or exchange the securities of Plum IV or CTR, or any commodity or instrument or related derivative, nor shall there be any sale of any such securities in any state or jurisdiction in which such offer, solicitation, sale or exchange would be unlawful prior to registration or qualification under the securities laws of any such state or jurisdiction. This Current Report is not, and under no circumstances is to be construed as, a prospectus, an advertisement or a public offering of the securities described herein in the United States or any other jurisdiction. No offer of securities shall be made except by means of a prospectus meeting the requirements of the Securities Act or an exemption therefrom. Investors should consult with their counsel as to the applicable requirements for a purchaser to avail itself of any exemption under the Securities Act.