Mountain Crest Acquisition 6 Corp. Sample Contracts

MOUNTAIN CREST ACQUISITION 6 CORP. UNDERWRITING AGREEMENT
Underwriting Agreement • May 5th, 2026 • Mountain Crest Acquisition 6 Corp. • Blank checks • New York

Mountain Crest Acquisition 6 Corp., a British Virgin Islands corporation (the “Company”), hereby confirms its agreement with D. Boral Capital LLC (the “Representative”), as representative of the several underwriters named on Schedule A hereto (the “Underwriters” or, each underwriter individually, an “Underwriter”), as follows:

REGISTRATION RIGHTS AGREEMENT
Registration Rights Agreement • May 5th, 2026 • Mountain Crest Acquisition 6 Corp. • Blank checks • New York

THIS REGISTRATION RIGHTS AGREEMENT (this “Agreement”), dated as of April 29, 2026, is made and entered into by and among Mountain Crest Acquisition 6 Corp., a British Virgin Islands business company (the “Company”), Mountain Crest Holdings 6 LLC, a Delaware limited liability company (the “Sponsor”) and each additional undersigned party listed on the signature page hereto, if any (each such party, together with the Sponsor and any person or entity who hereafter becomes a party to this Agreement pursuant to Section 5.2 of this Agreement, a “Holder” and collectively the “Holders”).

INVESTMENT MANAGEMENT TRUST AGREEMENT
Investment Management Trust Agreement • April 6th, 2026 • Mountain Crest Acquisition 6 Corp. • Blank checks

Pursuant to Section 1(k) of the Investment Management Trust Agreement between Mountain Crest Acquisition 6 Corp., (the “Company”) and Continental Stock Transfer & Trust Company (the “Trustee”), dated as of [●], 2026 (the “Trust Agreement”), the Company hereby requests that you deliver $[●] of the principal and interest income earned on the Property as of the date hereof to a segregated account held by you on behalf of Public Shareholders who have properly elected to have their Ordinary Shares that were sold by the Company in the IPO (the “Public Shares”) redeemed by the Company as described below. Capitalized terms used but not defined herein shall have the meanings set forth in the Trust Agreement.

RIGHTS AGREEMENT
Rights Agreement • May 5th, 2026 • Mountain Crest Acquisition 6 Corp. • Blank checks • New York

This Rights Agreement (this “Agreement”) is made as of April 29, 2026 between Mountain Crest Acquisition 6 Corp., a British Virgin Islands business company, with offices at 524 Broadway, 11th Floor, New York, NY 10012 (the “Company”), and Continental Stock Transfer & Trust Company, a New York corporation, with offices at 1 State Street, 30th Floor, New York, New York 10004 (the “Rights Agent”).

Mountain Crest Acquisition 6 Corp. 524 Broadway 11th Floor New York, NY 10012
Underwriting Agreement • May 5th, 2026 • Mountain Crest Acquisition 6 Corp. • Blank checks
Mountain Crest Acquisition 6 Corp. New York, NY 10012
Securities Subscription Agreement • April 6th, 2026 • Mountain Crest Acquisition 6 Corp. • Blank checks • New York

Mountain Crest Acquisition 6 Corp., a British Virgin Islands company (the “Company”), is pleased to accept the offer Mountain Crest Holdings 6 LLC, a Delaware limited liability company (the “Subscriber” or “you”) has made to subscribe for 2,957,143 ordinary shares of the Company (the “Shares”) with par value $0.0001 (the “Founder Shares”), up to 385,714 of which are subject to complete or partial forfeiture by you if the underwriters of the Company’s initial public offering (“IPO”) of units (“Units”) do not fully exercise their over-allotment option (the “Over-allotment Option”). The terms (this “Agreement”) on which the Company is willing to issue the Shares to the Subscriber, and the Company and the Subscriber’s agreements regarding such Shares, are as follows:

THIS INDEMNITY AGREEMENT (this “Agreement”) is made on [●], 2026. Between: Whereas:
Indemnification Agreement • April 6th, 2026 • Mountain Crest Acquisition 6 Corp. • Blank checks • Virgin Islands

NOW, THEREFORE, in consideration of the premises and the covenants contained herein and subject to the provisions of the letter agreement dated as of ________________, 2026 between the Company and Indemnitee pursuant to the underwriting agreement (“Underwriting Agreement”) between the Company and the underwriters in connection with the Company’s initial public offering, the Company and Indemnitee do hereby covenant and agree as follows:

REGISTRATION RIGHTS AGREEMENT
Registration Rights Agreement • April 6th, 2026 • Mountain Crest Acquisition 6 Corp. • Blank checks • New York

THIS REGISTRATION RIGHTS AGREEMENT (this “Agreement”), dated as of [●], 2026, is made and entered into by and among Mountain Crest Acquisition 6 Corp., a British Virgin Islands business company (the “Company”), Mountain Crest Holdings 6 LLC, a Delaware limited liability company (the “Sponsor”) and each additional undersigned party listed on the signature page hereto, if any (each such party, together with the Sponsor and any person or entity who hereafter becomes a party to this Agreement pursuant to Section 5.2 of this Agreement, a “Holder” and collectively the “Holders”).

MOUNTAIN CREST ACQUISITION 6 CORP. UNDERWRITING AGREEMENT
Underwriting Agreement • April 6th, 2026 • Mountain Crest Acquisition 6 Corp. • Blank checks • New York

Mountain Crest Acquisition 6 Corp., a British Virgin Islands corporation (the “Company”), hereby confirms its agreement with D. Boral Capital LLC (the “Representative”), as representative of the several underwriters named on Schedule A hereto (the “Underwriters” or, each underwriter individually, an “Underwriter”), as follows:

INVESTMENT MANAGEMENT TRUST AGREEMENT
Investment Management Trust Agreement • May 5th, 2026 • Mountain Crest Acquisition 6 Corp. • Blank checks

Pursuant to Section 1(k) of the Investment Management Trust Agreement between Mountain Crest Acquisition 6 Corp., (the “Company”) and Continental Stock Transfer & Trust Company (the “Trustee”), dated as of [●], 2026 (the “Trust Agreement”), the Company hereby requests that you deliver $[●] of the principal and interest income earned on the Property as of the date hereof to a segregated account held by you on behalf of Public Shareholders who have properly elected to have their Ordinary Shares that were sold by the Company in the IPO (the “Public Shares”) redeemed by the Company as described below. Capitalized terms used but not defined herein shall have the meanings set forth in the Trust Agreement.

MOUNTAIN CREST ACQUISITION 6 CORP. 524 Broadway 11th Floor New York, NY 10012
Office Space and Administrative Services Agreement • May 5th, 2026 • Mountain Crest Acquisition 6 Corp. • Blank checks

This letter will confirm our agreement that, commencing on the effective date (the “Effective Date”) of the registration statement (the “Registration Statement”) for the initial public offering (the “IPO”) of the securities of Mountain Crest Acquisition 6 Corp. (the “Company”) and continuing until the earlier of (i) the consummation by the Company of an initial business combination or (ii) the Company’s liquidation (in each case as described in the Registration Statement) (such earlier date hereinafter referred to as the “Termination Date”), Mountain Crest Holdings 6 LLC (“Sponsor”) shall make available to the Company certain office space, secretarial and administrative services as may be required by the Company from time to time, situated at 524 Broadway, 11th Floor, New York, NY 10012 (or any successor location). In exchange therefore, the Company shall pay Sponsor a sum not to exceed $10,000 per each quarter, respectively, on the Effective Date and continuing quarterly thereafter un

THIS INDEMNITY AGREEMENT (this “Agreement”) is made on April 29, 2026. Between: Whereas:
Indemnification Agreement • May 5th, 2026 • Mountain Crest Acquisition 6 Corp. • Blank checks • Virgin Islands

NOW, THEREFORE, in consideration of the premises and the covenants contained herein and subject to the provisions of the letter agreement dated as of April 29, 2026 between the Company and Indemnitee pursuant to the underwriting agreement (“Underwriting Agreement”) between the Company and the underwriters in connection with the Company’s initial public offering, the Company and Indemnitee do hereby covenant and agree as follows:

UNIT SUBSCRIPTION AGREEMENT
Unit Subscription Agreement • April 6th, 2026 • Mountain Crest Acquisition 6 Corp. • Blank checks • New York

This UNIT SUBSCRIPTION AGREEMENT (this “Agreement”) is made as of this [●], 2026, by and between Mountain Crest Acquisition 6 Corp., a British Virgin Islands business company (the “Company”), having its principal place of business at 524 Broadway, 11th Floor, New York, NY 10012, Mountain Crest Holdings 6 LLC, a Delaware limited liability company (the “Sponsor”), and D. Boral Capital LLC (“D. Boral”) (together, the “Purchasers”).

RIGHTS AGREEMENT
Rights Agreement • April 6th, 2026 • Mountain Crest Acquisition 6 Corp. • Blank checks • New York

This Rights Agreement (this “Agreement”) is made as of [●], 2026 between Mountain Crest Acquisition 6 Corp., a British Virgin Islands business company, with offices at 524 Broadway, 11th Floor, New York, NY 10012 (the “Company”), and Continental Stock Transfer & Trust Company, a New York corporation, with offices at 1 State Street, 30th Floor, New York, New York 10004 (the “Rights Agent”).

Mountain Crest Acquisition 6 Corp. 524 Broadway 11th Floor New York, NY 10012
Underwriting Agreement • April 6th, 2026 • Mountain Crest Acquisition 6 Corp. • Blank checks
UNIT SUBSCRIPTION AGREEMENT
Unit Subscription Agreement • May 5th, 2026 • Mountain Crest Acquisition 6 Corp. • Blank checks • New York

This UNIT SUBSCRIPTION AGREEMENT (this “Agreement”) is made as of this April 29, 2026, by and between Mountain Crest Acquisition 6 Corp., a British Virgin Islands business company (the “Company”), having its principal place of business at 524 Broadway, 11th Floor, New York, NY 10012, Mountain Crest Holdings 6 LLC, a Delaware limited liability company (the “Sponsor”), and D. Boral Capital LLC (“D. Boral”) (together, the “Purchasers”).