HCM Iii Acquisition Corp. Sample Contracts

HCM III ACQUISITION CORP Stamford, CT 06902
Securities Subscription Agreement • June 6th, 2025 • HCM Iii Acquisition Corp. • New York

We are pleased to accept the offer HCM Investor Holdings III, LLC (the “Subscriber” or “you”) has made to purchase 7,666,667 shares of Class B ordinary shares (the “Shares”), $0.0001 par value per share (the “Class B Ordinary Shares” together with all other classes of Company (as defined below) ordinary shares, the “Ordinary Shares”), up to 1,000,000 Shares of which are subject to complete or partial forfeiture by you if the underwriters of the initial public offering (“IPO”) of HCM III Acquisition Corp, a Cayman Islands exempted company (the “Company”), do not fully exercise their over-allotment option (the “Over-allotment Option”). The terms (this “Agreement”) on which the Company is willing to sell the Shares to the Subscriber, and the Company and the Subscriber’s agreements regarding such Shares, are as follows:

INDEMNITY AGREEMENT
Indemnity Agreement • June 6th, 2025 • HCM Iii Acquisition Corp. • New York

THIS INDEMNITY AGREEMENT (this “Agreement”) is made as of [●], 2025, by and between HCM III Acquisition Corp, a Cayman Islands exempted company (the “Company”), and the person executing this Agreement identified on the signature page hereto (“Indemnitee”).

INVESTMENT MANAGEMENT TRUST AGREEMENT
Investment Management Trust Agreement • June 6th, 2025 • HCM Iii Acquisition Corp.

This Investment Management Trust Agreement (this “Agreement”) is made effective as of [ ], 2025 by and between HCM III Acquisition Corp., a Cayman Islands exempted company (the “Company”), and Continental Stock Transfer & Trust Company, a New York corporation (the “Trustee”).

REGISTRATION AND SHAREHOLDER RIGHTS AGREEMENT
Registration and Shareholder Rights Agreement • June 6th, 2025 • HCM Iii Acquisition Corp. • New York

THIS REGISTRATION AND SHAREHOLDER RIGHTS AGREEMENT (this “Agreement”), dated as of [●], 2025, is made and entered into by and among HCM III Acquisition Corp, a Cayman Islands exempted company (the “Company”), HCM Investor Holdings III, LLC, a Delaware limited liability company (the “Sponsor”), and the undersigned parties listed under Holder on the signature page hereto (each such party, together with the Sponsor and any person or entity who hereafter becomes a party to this Agreement pursuant to Section 6.2 of this Agreement, a “Holder” and collectively the “Holders”).

PRIVATE PLACEMENT WARRANTS PURCHASE AGREEMENT
Private Placement Warrants Purchase Agreement • June 6th, 2025 • HCM Iii Acquisition Corp. • New York

THIS PRIVATE PLACEMENT WARRANTS PURCHASE AGREEMENT (as it may from time to time be amended and including all exhibits referenced herein, this “Agreement”), dated as of [●], 2025, is entered into by and between HCM III Acquisition Corp, a Cayman Islands exempted company (the “Company”), and Cantor Fitzgerald & Co., a company with its principal place of business in New York (the “Purchaser”).

WARRANT AGREEMENT
Warrant Agreement • June 6th, 2025 • HCM Iii Acquisition Corp. • New York

THIS WARRANT AGREEMENT (this “Agreement”), dated as of ____, 2025, is by and between HCM III Acquisition Corp., a Cayman Islands exempted company (the “Company”), and Continental Stock Transfer & Trust Company, a New York corporation, as warrant agent (in such capacity, the “Warrant Agent,” and also referred to herein as the “Transfer Agent”).

HCM III Acquisition Corp. Stamford, CT 06902 Re: Initial Public Offering Ladies and Gentlemen:
Letter Agreement • June 6th, 2025 • HCM Iii Acquisition Corp.

This letter (this “Letter Agreement”) is being delivered to you in accordance with the Underwriting Agreement (the “Underwriting Agreement”) entered into by and among HCM III Acquisition Corp., a Cayman Islands exempted company (the “Company”) and Cantor Fitzgerald& Co. as representative (the “Representative”) of the underwriters (the “Underwriters”), relating to an underwritten initial public offering (the “Public Offering”), of up to 25,300,000 of the Company’s units (including up to 3,300,000 units which may be purchased to cover over- allotments, if any) (the “Units”), each comprised of one Class A ordinary share, par value $0.0001 per share, of the Company (the “Class A Ordinary Shares”) and one-half of one redeemable warrant (each whole warrant, a “Warrant”). Each Warrant entitles the holder thereof to purchase one Class A Ordinary Share at a price of $11.50 per share, subject to adjustment. The Units shall be sold in the Public Offering pursuant to the registration statement on

UNDERWRITING AGREEMENT between HCM III ACQUISITION CORP. and CANTOR FITZGERALD & CO., As Representative of the Underwriters Dated: July 31, 2025 HCM III ACQUISITION CORP. UNDERWRITING AGREEMENT
Underwriting Agreement • August 5th, 2025 • HCM Iii Acquisition Corp. • Blank checks • New York

The undersigned, HCM III Acquisition Corp., a Cayman Islands exempted company (the “Company”), hereby confirms its agreement with Cantor Fitzgerald & Co. (“Cantor Fitzgerald” or the “Representative”) and with the other underwriters named on Schedule A hereto (if any), for which the Representative is acting as representative (the Representative and such other underwriters being collectively referred to herein as the “Underwriters” or, each underwriter individually, an “Underwriter,” provided that, if only Cantor is listed on such Schedule A, any reference to Underwriters shall refer exclusively to Cantor) as follows:

INVESTMENT MANAGEMENT TRUST AGREEMENT
Investment Management Trust Agreement • August 5th, 2025 • HCM Iii Acquisition Corp. • Blank checks

This Investment Management Trust Agreement (this “Agreement”) is made effective as of July 31, 2025 by and between HCM III Acquisition Corp., a Cayman Islands exempted company (the “Company”), and Continental Stock Transfer & Trust Company, a New York corporation (the “Trustee”).

WARRANT AGREEMENT
Warrant Agreement • August 5th, 2025 • HCM Iii Acquisition Corp. • Blank checks • New York

THIS WARRANT AGREEMENT (this “Agreement”), dated as of July 31, 2025, is by and between HCM III Acquisition Corp., a Cayman Islands exempted company (the “Company”), and Continental Stock Transfer & Trust Company, a New York corporation, as warrant agent (in such capacity, the “Warrant Agent,” and also referred to herein as the “Transfer Agent”).

UNDERWRITING AGREEMENT between HCM III ACQUISITION CORP. and CANTOR FITZGERALD & CO., As Representative of the Underwriters Dated: [ ], 2025 HCM III ACQUISITION CORP. UNDERWRITING AGREEMENT
Underwriting Agreement • July 11th, 2025 • HCM Iii Acquisition Corp. • Blank checks • New York

The undersigned, HCM III Acquisition Corp., a Cayman Islands exempted company (the “Company”), hereby confirms its agreement with Cantor Fitzgerald & Co. (“Cantor Fitzgerald” or the “Representative”) and with the other underwriters named on Schedule A hereto (if any), for which the Representative is acting as representative (the Representative and such other underwriters being collectively referred to herein as the “Underwriters” or, each underwriter individually, an “Underwriter,” provided that, if only Cantor is listed on such Schedule A, any reference to Underwriters shall refer exclusively to Cantor) as follows:

HCM III ACQUISITION CORP
Sponsorship Agreement • August 5th, 2025 • HCM Iii Acquisition Corp. • Blank checks

This letter will confirm our agreement that, commencing on the effective date (the “Effective Date”) of the registration statement on Form S-1 (the “Registration Statement”) for the initial public offering (the “IPO”) of the securities of HCM III Acquisition Corp, a Cayman Islands exempted company (the “Company”), and continuing until the earlier of (i) the consummation by the Company of an initial business combination and (ii) the Company’s liquidation (in each case, as described in the Registration Statement) (such earlier date hereinafter referred to as the “Termination Date”), HCM Investor Holdings III, LLC, a Delaware limited liability company (the “Sponsor”), shall take steps directly or indirectly to make available to the Company, at 100 First Stamford Place, Suite 330, Stamford, Connecticut 06902 (or any successor location), office space and secretarial and administrative services as may be required by the Company from time to time. In exchange therefor, the Company shall pay t

REGISTRATION AND SHAREHOLDER RIGHTS AGREEMENT
Registration and Shareholder Rights Agreement • August 5th, 2025 • HCM Iii Acquisition Corp. • Blank checks • New York

THIS REGISTRATION AND SHAREHOLDER RIGHTS AGREEMENT (this “Agreement”), dated as of July 31, 2025, is made and entered into by and among HCM III Acquisition Corp, a Cayman Islands exempted company (the “Company”), HCM Investor Holdings III, LLC, a Delaware limited liability company (the “Sponsor”), and the undersigned parties listed under Holder on the signature page hereto (each such party, together with the Sponsor and any person or entity who hereafter becomes a party to this Agreement pursuant to Section 6.2 of this Agreement, a “Holder” and collectively the “Holders”).

HCM III ACQUISITION CORP
Sponsorship Agreement • June 6th, 2025 • HCM Iii Acquisition Corp.
PRIVATE PLACEMENT WARRANTS PURCHASE AGREEMENT
Private Placement Warrants Purchase Agreement • August 5th, 2025 • HCM Iii Acquisition Corp. • Blank checks • New York

THIS PRIVATE PLACEMENT WARRANTS PURCHASE AGREEMENT (as it may from time to time be amended and including all exhibits referenced herein, this “Agreement”), dated as of July 31, 2025, is entered into by and between HCM III Acquisition Corp, a Cayman Islands exempted company (the “Company”), and Cantor Fitzgerald & Co., a company with its principal place of business in New York (the “Purchaser”).

July 31, 2025 HCM III Acquisition Corp. Re: Initial Public Offering Ladies and Gentlemen:
Underwriting Agreement • August 5th, 2025 • HCM Iii Acquisition Corp. • Blank checks

This letter (this “Letter Agreement”) is being delivered to you in accordance with the Underwriting Agreement (the “Underwriting Agreement”) entered into by and among HCM III Acquisition Corp., a Cayman Islands exempted company (the “Company”) and Cantor Fitzgerald& Co. as representative (the “Representative”) of the underwriters (the “Underwriters”), relating to an underwritten initial public offering (the “Public Offering”), of up to 25,300,000 of the Company’s units (including up to 3,300,000 units which may be purchased to cover over- allotments, if any) (the “Units”), each comprised of one Class A ordinary share, par value $0.0001 per share, of the Company (the “Class A Ordinary Shares”) and one-half of one redeemable warrant (each whole warrant, a “Warrant”). Each Warrant entitles the holder thereof to purchase one Class A Ordinary Share at a price of $11.50 per share, subject to adjustment. The Units shall be sold in the Public Offering pursuant to the registration statement on