Description of Organization and Business Operations

3 Months Ended

Mar. 31, 2026

Description of Organization and Business Operations [Abstract]

DESCRIPTION OF ORGANIZATION AND BUSINESS OPERATIONS

NOTE 1 — DESCRIPTION OF ORGANIZATION AND BUSINESS OPERATIONS

Plum Acquisition Corp. IV (the “Company”) is a blank check company incorporated as a Cayman Islands exempted corporation on June 10, 2024. The Company was incorporated for the purpose of effecting a merger, share exchange, asset acquisition, share purchase, reorganization or similar business combination with one or more businesses (“Business Combination”).

The Company is not limited to a particular industry or geographic region for purposes of completing a Business Combination. The Company is an early stage and emerging growth company and, as such, the Company is subject to all of the risks associated with early stage and emerging growth companies.

As of March 31, 2026, the Company had not commenced any operations. All activity for the period from June 10, 2024 (inception) through March 31, 2026 relates to the Company’s formation and the initial public offering (“Initial Public Offering”), which is described below, and, after the Initial Public Offering, identifying a target company for a Business Combination. The Company will not generate any operating revenues until after the completion of a Business Combination, at the earliest. The Company will generate non-operating income in the form of interest income from the proceeds derived from the Initial Public Offering. The Company has selected December 31 as its fiscal year end.

The registration statement for the Company’s Initial Public Offering was declared effective on January 14, 2025. On January 16, 2025, the Company consummated the Initial Public Offering of 17,250,000 units (the “Units” and, with respect to the Class A ordinary shares included in the Units being offered, the “Public Shares”), which included the full exercise by the underwriters of their over-allotment option in the amount of 2,250,000 Units, at $10.00 per Unit, generating gross proceeds of $172,500,000, which is discussed in Note 3.

Simultaneously with the closing of the Initial Public Offering, the Company consummated the sale of an aggregate of 672,875 private placement units (each, a “Private Placement Unit”) at a price of $10.00 per Private Placement Unit, generating gross proceeds of $6,728,750, as follows: (i) by and among the Company and each of the underwriters for the purchase by the underwriters of an aggregate of 232,875 private placement units for an aggregate purchase price of $2,328,750 and (ii) by and between the Company and Plum Partners IV, LLC (the “Sponsor”) for the purchase by the Sponsor of an aggregate of 440,000 private placement units and 570,000 restricted Class A ordinary shares for an aggregate purchase price of $4,400,000. The private placement units are identical to the units sold in this offering, subject to certain limited exceptions as described in the prospectus.

Transaction costs amounted to $10,932,289, consisting of $3,450,000 of cash underwriting fee, $6,900,000 of deferred underwriting fee, and $582,289 of other offering costs.

The Company’s management has broad discretion with respect to the specific application of the net proceeds of the Initial Public Offering and the sale of the Private Placement Securities, although substantially all of the net proceeds are intended to be applied generally toward completing a Business Combination. The Company must complete its initial Business Combination with one or more target businesses that together have a fair market value equal to at least 80% of the net assets held in the Trust Account (as defined below) (excluding any deferred underwriting commissions held in the Trust Account) at the time of the agreement to enter into a Business Combination. The Company will only complete a Business Combination if the post-Business Combination company owns or acquires 50% or more of the issued and outstanding voting securities of the target or otherwise acquires a controlling interest in the target business sufficient for it not to be required to register as an investment company under the Investment Company Act of 1940, as amended (the “Investment Company Act”). There is no assurance that the Company will be able to successfully effect a Business Combination.

Following the closing of the Initial Public Offering, on January 16, 2025, an amount of $174,225,000 ($10.10 per Unit) from the net proceeds of the sale of the Units and the sale of the Private Placement Securities was placed in the trust account (the “Trust Account”) and invested or held in either (i) U.S. government treasury bills with a maturity of 185 days or less or in money market funds investing solely in U.S. Treasuries, (ii) uninvested cash, or (iii) an interest bearing bank demand deposit account or other accounts at a bank, as determined by the Company, until the earlier of: (i) the completion of a Business Combination or (ii) the distribution of the funds in the Trust Account to the Company’s shareholders, as described below. No later than 18 months after the closing of the Initial Public Offering or such earlier liquidation date as the Company’s board of directors may approve, or such later time as provided for in any amendment to the Company’s Amended and Restated Memorandum and Articles of Association (an “Extension Period”), subject to applicable law, the amounts held in the Trust Account are held as cash or cash items, including in demand deposit accounts.

The Company will provide its shareholders with the opportunity to redeem all or a portion of their Public Shares upon the completion of a Business Combination either (i) in connection with a general meeting called to approve the Business Combination or (ii) by means of a tender offer. The decision as to whether the Company will seek shareholder approval of a Business Combination or conduct a tender offer will be made by the Company. The shareholders will be entitled to redeem their shares for a pro rata portion of the amount held in the Trust Account (initially $10.10 per share), calculated as of two business days prior to the completion of a Business Combination, including any pro rata interest earned on the funds held in the Trust Account and not previously released to the Company to pay its tax obligations. There will be no redemption rights upon the completion of a Business Combination with respect to the Company’s public warrants.

If the Company seeks shareholder approval in connection with a Business Combination, it receives an ordinary resolution under Cayman Islands law approving a Business Combination, which requires the affirmative vote of a majority of the shareholders who vote at a general meeting of the Company. If a shareholder vote is not required under applicable law or stock exchange listing requirements and the Company does not decide to hold a shareholder vote for business or other reasons, the Company will, pursuant to its Amended and Restated Memorandum and Articles of Association, conduct the redemptions pursuant to the tender offer rules of the Securities and Exchange Commission (“SEC”), and file tender offer documents containing substantially the same information as would be included in a proxy statement with the SEC prior to completing a Business Combination.

If the Company seeks shareholder approval in connection with a Business Combination, the Sponsor has agreed to vote its Founder Shares (as defined in Note 5) and any Public Shares purchased in or after the Initial Public Offering in favor of approving a Business Combination and to waive its redemption rights with respect to any such shares in connection with a shareholder vote to approve a Business Combination. Additionally, each public shareholder may elect to redeem its Public Shares, without voting, and if they do vote, irrespective of whether they vote for or against a proposed Business Combination.

Notwithstanding the foregoing, if the Company seeks shareholder approval of a Business Combination and it does not conduct redemptions pursuant to the tender offer rules, the Company’s Amended and Restated Memorandum and Articles of Association provides that a public shareholder, together with any affiliate of such shareholder or any other person with whom such shareholder is acting in concert or as a “group” (as defined under Section 13 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”)), will be restricted from redeeming its shares with respect to more than an aggregate of 15% of the Public Shares without the Company’s prior written consent.

The Sponsor has agreed to (i) waive its redemption rights with respect to its private placement shares in connection with the completion of the initial business combination, (ii) waive its redemption rights with respect to its private placement shares in connection with a shareholder vote to approve an amendment to the amended and restated memorandum and articles of association (A) to modify the substance or timing of the obligation to allow redemption in connection with the initial Business Combination or to redeem 100% of the public shares if the Company fails to complete the initial Business Combination within 18 months from the closing of the Initial Public Offering or such earlier liquidation date as the Company’s board of directors may approve, or during any Extension Period, subject to applicable law or (B) with respect to any other provision relating to shareholders’ rights or pre-initial business combination activity and (iii) waive its rights to liquidating distributions from the Trust Account with respect to its private placement shares if the Company fails to complete the initial Business Combination within the prescribed timeframe. In addition, the Sponsor has agreed to vote any private placement shares held by it in favor of the initial Business Combination.

The Company will have until 18 months from the closing of the Initial Public Offering (the “Combination Period”) to complete a Business Combination. If the Company is unable to complete a Business Combination within the Combination Period, the Company will (i) cease all operations except for the purpose of winding up, (ii) as promptly as reasonably possible but no more than 10 business days thereafter, redeem 100% of the outstanding Public Shares, at a per-share price, payable in cash, including interest earned on the funds held in the Trust Account (which interest shall be net of taxes payable and up to $100,000 of interest to pay dissolution expenses) and not previously released to the Company to pay its taxes, if any, divided by the number of then-outstanding Public Shares, which redemption will completely extinguish public shareholders’ rights as shareholders (including the right to receive further liquidation distributions, if any), and (iii) as promptly as reasonably possible following such redemption, subject to the approval of the remaining shareholders and the Company’s board of directors, liquidate and dissolve, subject in each case to its obligations under Cayman Islands law to provide for claims of creditors and the requirements of other applicable law.

The Sponsor has agreed to waive its liquidation rights with respect to the Founder Shares if the Company fails to complete a Business Combination within the Combination Period. However, if the Sponsor acquires Public Shares in or after the Initial Public Offering, such Public Shares will be entitled to liquidating distributions from the Trust Account if the Company fails to complete a Business Combination within the Combination Period. The underwriters have agreed to waive their rights to their deferred underwriting commission (see Note 6) held in the Trust Account in the event the Company does not complete a Business Combination within the Combination Period and, in such event, such amounts will be included with the funds held in the Trust Account that will be available to fund the redemption of the Public Shares. In the event of such distribution, it is possible that the per share value of the assets remaining available for distribution will be less than the initial amount held in the Trust Account ($10.10).

The Sponsor has agreed that it will be liable to the Company, if and to the extent any claims by a third party for services rendered or products sold to the Company, or by a prospective target business with which the Company has discussed entering into a transaction agreement, reduce the amount of funds in the Trust Account to below (1) $10.10 per Public Share or (2) such lesser amount per Public Share held in the Trust Account as of the date of the liquidation of the Trust Account due to reductions in the value of trust assets, in each case net of the amount of interest which may be withdrawn to pay taxes. This liability will not apply with respect to any claims by a third party who executed a waiver of any and all rights to seek access to the Trust Account nor will it apply to any claims under the Company’s indemnity of the underwriters of the Initial Public Offering against certain liabilities, including liabilities under the Securities Act of 1933, as amended (the “Securities Act”). Moreover, in the event that an executed waiver is deemed to be unenforceable against a third party, the Sponsor will not be responsible to the extent of any liability for such third-party claims. The Company will seek to reduce the possibility that the Sponsor will have to indemnify the Trust Account due to claims of creditors by endeavoring to have all vendors, service providers (other than the Company’s independent auditors), prospective target businesses or other entities with which the Company does business, execute agreements with the Company waiving any right, title, interest or claim of any kind in or to monies held in the Trust Account.

Proposed Business Combination

Business Combination Agreement

On March 8, 2026, the Company entered into a business combination agreement (the “Business Combination Agreement”) by and among the Company, Plum IV Merger Sub, Inc., a Delaware corporation and a direct wholly owned subsidiary of the Company (“Merger Sub”), and Controlled Thermal Resources Holdings Inc., a Delaware corporation (“CTR”), pursuant to which, among other things and subject to the terms and conditions contained therein, Merger Sub will merge with and into CTR (the “Merger”), with CTR continuing as the surviving company. The transactions contemplated by the Business Combination Agreement are referred to in this Annual Report as the “Business Combination.” The combined company’s business is expected to continue to operate through CTR. The proposed Merger is expected to be consummated after receipt of the required approvals by the Company’s shareholders and CTR’s stockholders and the satisfaction or waiver of certain other customary conditions.

Domestication

At least two (2) business days prior to the Closing Date (as defined in the Business Combination Agreement), subject to the satisfaction or waiver of the conditions of the Business Combination Agreement, the Company will transfer by way of continuation from the Cayman Islands to the State of Delaware and domesticate as a Delaware corporation (“Domesticated Plum IV”) in accordance with Section 388 of the General Corporation Law of the State of Delaware, as amended, and Part 12 of the Companies Act (as revised) of the Cayman Islands (such continuation and domestication, the “Domestication”).

By virtue of the Domestication upon its effectiveness, (a) each then issued and outstanding Class A ordinary share, par value $0.0001 per share, of the Company (each a “Class A Ordinary Share”) (other than any Class A Ordinary Share included in the Cayman Purchaser Units (as defined in the Business Combination Agreement)) shall convert automatically, on a one-for-one basis, into one (1) share of common stock of Domesticated Plum IV (the “Domesticated Purchaser Common Stock”); (b) each then issued and outstanding Class B ordinary share, par value $0.0001 per share, of the Company (each a “Class B Ordinary Share”) shall convert automatically, on a one-for-one basis, into one (1) share of Class B common stock of Domesticated Plum IV (the “Domesticated Purchaser Class B Common Stock”); (c) each then issued and outstanding warrant of the Company (other than any Cayman Purchaser Public Warrants (as defined in the Business Combination Agreement)) included in the Cayman Purchaser Units) (each a “Cayman Purchaser Warrant”) shall convert automatically into a warrant to acquire one (1) share of Domesticated Purchaser Common Stock (each a “Domesticated Purchaser Warrant”), pursuant to the Warrant Agreement (as defined in the Business Combination Agreement); and (d) each then issued and outstanding Cayman Purchaser Unit shall be cancelled and will thereafter entitle the holder thereof to one (1) share of Domesticated Purchaser Common Stock and one-half of one (1) Domesticated Purchaser Warrant, in each case without any action on the part of the Company, Merger Sub, the Company or any holder of securities of any of the foregoing.

The Merger and Consideration

Following the Domestication, at the Effective Time (as defined in the Business Combination Agreement), by virtue of the Merger, each share of capital stock of Merger Sub issued and outstanding immediately prior to the Effective Time shall be automatically cancelled and extinguished and converted into one (1) share of common stock, par value $0.0001 per share, of the surviving company.

Subject to, and in accordance with the terms and conditions of the Business Combination Agreement, at the Effective Time (as defined in the Business Combination Agreement):

(vi) each share of common stock of CTR (the “CTR Common Stock”) issued and outstanding (or deemed to be issued and outstanding under the terms of the Business Combination Agreement) immediately prior to the Effective Time, except for (a) shares held by the Company or Merger Sub (or any subsidiaries of the Company), (b) shares held by the CTR as treasury stock, if any (each share covered in subclause (a) and (b), an “Excluded Share”), (c) shares held by stockholders who have properly exercised and not withdrawn appraisal rights under Delaware law (the “Dissenting Shares”), and (d) shares of CTR Common Stock issued pursuant to an award of restricted stock that is, as of immediately prior to the Closing Date (as defined in the Business Combination Agreement), subject to a substantial risk of forfeiture and is not transferable (the “CTR Restricted Shares”), will be cancelled and converted into the right to receive the Per Share Merger Consideration (as defined in the Business Combination Agreement);

(vii) each Excluded Share shall be automatically cancelled and retired without any conversion thereof and shall cease to exist, and no consideration shall be delivered in exchange therefor;

(viii) each option to purchase shares of the CTR Common Stock (the “CTR Option”) that is outstanding immediately prior to the Effective Time will be automatically assumed by Domesticated Plum IV and converted into an option to purchase a number of shares of Domesticated Purchaser Common Stock equal to the product (rounded down to the nearest whole number) of (x) the number of shares of CTR Common Stock subject to such CTR Option immediately prior to the Effective Time and (y) the Exchange Ratio (as defined in the Business Combination Agreement), at an exercise price per share (rounded up to the nearest whole cent) equal to the quotient of (A) the exercise price per share of such CTR Option immediately prior to the Effective Time divided by (B) the Exchange Ratio;

(ix) each award of the CTR Restricted Shares (the “CTR Restricted Share Award”) that is outstanding immediately prior to the Effective Time will be automatically assumed by Domesticated Plum IV such that each CTR Restricted Share Award will be converted into an award for a number of restricted shares of Domesticated Purchaser Common Stock equal to the product (rounded down to the nearest whole number) of (x) the number of shares of CTR Restricted Shares and (y) the Exchange Ratio; and

(x) each warrant to purchase shares of the CTR Common Stock (the “CTR Warrant”) that is outstanding immediately prior to the Effective Time will be automatically assumed by the Domesticated Plum IV such that, as of the Effective Time, each CTR Warrant shall instead be converted into a warrant to purchase a number of shares of Domesticated Purchaser Common Stock equal to the product (rounded down to the nearest whole number) of (x) the number of shares of CTR Common Stock issuable upon exercise of such CTR Warrant and (y) the Exchange Ratio, at an exercise price per share (rounded up to the nearest whole cent) equal to the quotient of (A) the exercise price per share of such CTR Warrant immediately prior to the Effective Time divided by (B) the Exchange Ratio.

The Class B Conversion

At the Effective Time, by virtue of the Merger and the applicable provisions of the certificate of incorporation of Domesticated Plum IV (the “Domesticated Purchaser Charter”), each share of Domesticated Purchaser Class B Common Stock then issued and outstanding shall be automatically cancelled and extinguished and converted into one (1) share of Domesticated Purchaser Common Stock.

Transaction Support Agreement

Simultaneously with the execution and delivery of the Business Combination Agreement, the Company and certain stockholders of CTR, who collectively have the right to cast at least 60% of the votes entitled to be cast at a special meeting of CTR’s stockholders (collectively, the “Supporting CTR Stockholders”) entered into a Transaction Support Agreement (the “Transaction Support Agreement”), pursuant to which the Supporting CTR Stockholders have agreed, among other things, to vote all of their shares of CTR’s common stock in favor of adopting and approving the Business Combination Agreement and the Business Combination.

Registration Rights Agreement

In connection with the Business Combination, simultaneously with the closing of the Business Combination (the “Closing”), the Company and certain holders will enter into an amended and restated Registration Rights Agreement (the “Amended and Restated Registration Rights Agreement”) that amends and restates the Registration Rights Agreement, dated January 14, 2025, by and among the Company, the Sponsor and certain other security holders named therein, pursuant to which, among other things, (i) the Company will agree to file, as soon as practicable (and in any event within thirty (30) calendar days) following the closing date, a registration statement covering the resale of certain equity securities held by the Sponsor and such other securityholders parties thereto; and (ii) such holders of registrable securities will be granted certain takedown, demand, block trade and piggyback registration rights with respect to their registrable securities, in each case, on the terms and subject to the conditions set forth in the Amended and Restated Registration Rights Agreement.

Lock-Up Agreement

In connection with the Business Combination, simultaneously with the closing, the Company, the Sponsor and certain stockholders of CTR (such holders, collectively, the “Lock-Up Parties”) will enter into a Lock-Up Agreement (the “Lock-Up Agreement”). The Lock-Up Agreement will provide that, during the applicable Lock-Up Period (as defined in the Lock-Up Agreement), subject to certain exceptions, the Lock-Up Parties will not, with respect to the Lock-Up Securities (as defined in the Lock-Up Agreement), (i) sell, offer to sell, contract or agree to sell, hypothecate, pledge, grant any option to purchase or otherwise dispose of or agree to dispose of, directly or indirectly, or establish or increase a put equivalent position or liquidation with respect to or decrease a call equivalent position, (ii) enter into any swap or other arrangement that transfers to another, in whole or in part, any of the economic consequences of ownership of any security, whether any such transaction is to be settled by delivery of such securities, in cash or otherwise, or (iii) publicly announce the intention to effect any transaction specified in clause (i) or (ii).

Risks and Uncertainties

The Company’s ability to complete an initial Business Combination may be adversely affected by various factors, many of which are beyond the Company’s control. The Company’s ability to consummate an initial Business Combination could be impacted by, among other things, changes in laws or regulations, downturns in the financial markets or in economic conditions, inflation, fluctuations in interest rates, increases in tariffs, supply chain disruptions, declines in consumer confidence and spending, public health considerations, and geopolitical instability, such as the military conflicts in Ukraine and the Middle East. The Company cannot at this time predict the likelihood of one or more of the above events, their duration or magnitude or the extent to which they may negatively impact the Company’s ability to complete an initial Business Combination.