EX-10.4





 Exhibit 10.4 

PRIVATE PLACEMENT WARRANTS PURCHASE AGREEMENT 

THIS PRIVATE PLACEMENT WARRANTS PURCHASE AGREEMENT, dated as of October 21, 2021 (as it may from time to time be amended and including
all exhibits referenced herein, this “Agreement”), is entered into by and between M3-Brigade Acquisition III Corp., a Delaware corporation (the “Company”), and M3-Brigade Sponsor III LP, a Delaware limited partnership (the “Purchaser”). 
 WHEREAS,
the Company intends to consummate an initial public offering of the Company’s units (the “Public Offering”), each unit consisting of one share of the Company’s Class A common stock, par value $0.0001 per share (each,
a “Share”), and one-third of one redeemable warrant. Each whole warrant entitles the holder to purchase one Share at an exercise price of $11.50 per Share. The Purchaser has agreed to purchase
an aggregate of 5,526,667 warrants (or up to 5,787,667 warrants, depending on the extent to which the underwriters exercise their option to purchase additional units) (the “Private Placement Warrants”), each Private Placement
Warrant entitling the holder to purchase one Share at an exercise price of $11.50 per Share. Cantor Fitzgerald & Co., the representative of the underwriters (“Cantor”), has agreed to purchase 1,740,000 Private Placement
Warrants pursuant to a separate agreement between Cantor and the Company. 
 NOW THEREFORE, in consideration of the mutual promises
contained in this Agreement and other good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, the parties to this Agreement hereby, intending legally to be bound, agree as follows: 

AGREEMENT 
 Section 1.
Authorization, Purchase and Sale; Terms of the Private Placement Warrants. 
 A. Authorization of the Private Placement Warrants.
The Company has duly authorized the issuance and sale of the Private Placement Warrants to the Purchaser. 
 B. Purchase and Sale of the
Private Placement Warrants. 
 On the date of the consummation of the Public Offering and concurrently with the consummation thereof, or
on such earlier time and date as may be mutually agreed by the Purchaser and the Company (the “Initial Closing Date”), the Company shall issue and sell to the Purchaser, and the Purchaser shall purchase from the Company, 5,526,667
Private Placement Warrants at a price of $1.50 per Private Placement Warrant for an aggregate purchase price of $8,290,000 (the “Purchase Price”). The Purchase Price shall be paid by wire transfer of immediately available funds to
the Company in accordance with the Company’s wiring instructions at least one business day prior to the date of effectiveness of the registration statement on Form S-1 (File
No.333-256017) filed in connection with the Public Offering. On the Initial Closing Date, the Company, shall either, at its option, deliver a certificate evidencing the Private Placement Warrants purchased by
the Purchaser on such date duly registered in the Purchaser’s name to the Purchaser, or effect such delivery in book-entry form. On the date of the consummation of the closing of the over-allotment option in connection with the Public Offering,













 
and concurrently with the consummation thereof, or on such earlier time and date as may be mutually agreed by the Purchaser and the Company (each such date, an “Over-allotment Closing
Date”; together with the Initial Closing Date, the “Closing Dates” and each, a “Closing Date”), the Company shall issue and sell to the Purchaser, and the Purchaser shall purchase from the Company, up to an aggregate of
261,000 Private Placement Warrants, in the same proportion as the amount of the over-allotment option that is exercised, at a price of $1.50 per warrant for an aggregate purchase price of up to $391,500 (if the over-allotment option in connection
with the Public Offering is exercised in full) (the “Over-allotment Purchase Price”), which shall be paid by wire transfer of immediately available funds to the Company in accordance with the Company’s wiring instructions. On the
Over-allotment Closing Date, upon the payment by the Purchaser of the Over-allotment Purchase Price payable by it by wire transfer of immediately available funds to the Company, the Company shall either, at its option, deliver a certificate
evidencing the Private Placement Warrants purchased by the Purchaser on such date duly registered in the Purchaser’s names to the Purchaser, or effect such delivery in book-entry form. 

C. Terms of the Private Placement Warrants. 

(i) The Private Placement Warrants shall have their terms set forth in a Private Warrant Agreement to be entered into by the Company and a
warrant agent, in connection with the Public Offering (a “Private Warrant Agreement”). 
 (ii) At or prior to the
time of the Initial Closing Date, the Company and the Purchaser shall enter into a registration and stockholder rights agreement (the “Registration and Stockholder Rights Agreement”) pursuant to which the Company will grant certain
registration rights to the Purchaser relating to the Private Placement Warrants and the Shares underlying the Private Placement Warrants. 

Section 2. Representations and Warranties of the Company. As a material inducement to the Purchaser to
enter into this Agreement and purchase the Private Placement Warrants, the Company hereby represents and warrants to the Purchaser (which representations and warranties shall survive each Closing Date) that: 

A. Organization and Corporate Power. The Company is a corporation duly organized, validly existing and in good standing under the laws
of the State of Delaware and is qualified to do business in every jurisdiction in which the failure to so qualify would reasonably be expected to have a material adverse effect on the financial condition, operating results or assets of the Company.
The Company possesses all requisite corporate power and authority necessary to carry out the transactions contemplated by this Agreement and the Private Warrant Agreement. 

B. Authorization; No Breach. 

(i) The execution, delivery and performance of this Agreement and the Private Placement Warrants have been duly authorized and approved by
the Company as of each Closing Date. This Agreement constitutes a valid and binding obligation of the Company, enforceable in accordance with its terms. Upon issuance in accordance with, and payment pursuant to, the terms of the Private Warrant
Agreement and this Agreement, the Private Placement Warrants will constitute valid and binding obligations of the Company, enforceable in accordance with their terms. 

  
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 (ii) The execution and delivery by the Company of this Agreement and the Private Placement
Warrants, the issuance and sale of the Private Placement Warrants, the issuance of the Shares upon exercise of the Private Placement Warrants and the fulfillment of, and compliance with, the respective terms hereof and thereof by the Company, do not
and will not as of each Closing Date (a) conflict with or result in a breach of the terms, conditions or provisions of, (b) constitute a default under, (c) result in the creation of any lien, security interest, charge or encumbrance
upon the Company’s capital stock or assets under, (d) result in a violation of, or (e) require any authorization, consent, approval, exemption, action, notice, declaration or filing, in each case, by or to any court or administrative
or governmental body or agency pursuant to the certificate of incorporation or the bylaws of the Company (in effect on the date hereof or as may be amended prior to completion of the contemplated Public Offering), or any material law, statute, rule
or regulation to which the Company is subject, or any agreement, order, judgment or decree to which the Company is subject, except for any filings required after the date hereof under federal or state securities laws. 

C. Title to Securities. Upon issuance in accordance with, and payment pursuant to, the terms hereof and the Private Warrant Agreement,
the Placement Warrants will be duly and validly issued and the Shares issuable upon exercise of the Private Placement Warrants will be duly and validly issued, fully paid and nonassessable. On the date of issuance of the Placement Warrants, the
Shares issuable upon exercise of the Placement Warrants shall have been reserved for issuance. Upon issuance in accordance with, and payment pursuant to, the terms hereof and the Private Warrant Agreement, the Purchaser will have good title to the
Private Placement Warrants and the Shares issuable upon exercise of such Private Placement Warrants, free and clear of all liens, claims and encumbrances of any kind, other than (i) transfer restrictions hereunder and under the other agreements
contemplated hereby, (ii) transfer restrictions under federal and state securities laws, and (iii) liens, claims or encumbrances imposed due to the actions of the Purchaser. 

D. Valid Issuance. The total number of shares of all classes of capital stock which the Company has authority to issue is 550,000,000
shares of common stock (which consist of 500,000,000 shares of the Company’s Class A Common Stock and 50,000,000 shares of the Company’s Class B common stock, par value $0.0001 per share (the “Class B
Common Stock”)) and 1,000,000 shares of the Company’s preferred stock, par value $0.0001, per share (the “Preferred Stock”). As of the date hereof, the Company has issued and outstanding no shares of Class A
Common Stock, 7,503,750 shares of Class B Common Stock (of which up to 978,750 shares are subject to forfeiture as described in the Registration Statement) and no shares of Preferred Stock. All of the issued shares of capital stock of the
Company have been duly authorized, validly issued, and are fully paid and non-assessable. 
 E.
Governmental Consents. No permit, consent, approval or authorization of, or declaration to or filing with, any governmental authority is required in connection with the execution, delivery and performance by the Company of this Agreement or
the consummation by the Company of any other transactions contemplated hereby. 

  
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 Section 3. Representations and Warranties of the
Purchaser. As a material inducement to the Company to enter into this Agreement and issue and sell the Private Placement Warrants to the Purchaser, the Purchaser hereby represents and warrants to the Company (which representations and
warranties shall survive each Closing Date) that: 
 A. Organization and Requisite Authority. The Purchaser possesses all requisite
power and authority necessary to carry out the transactions contemplated by this Agreement. 
 B. Authorization; No Breach. 

(i) This Agreement constitutes a valid and binding obligation of the Purchaser, enforceable in accordance with its terms, subject to
bankruptcy, insolvency, fraudulent conveyance, reorganization, moratorium and other laws of general applicability relating to or affecting creditors’ rights and to general equitable principles (whether considered in a proceeding in equity or
law). 
 (ii) The execution and delivery by the Purchaser of this Agreement and the fulfillment of and compliance with the terms hereof by
the Purchaser does not and shall not as of each Closing Date conflict with or result in a breach by the Purchaser of the terms, conditions or provisions of any agreement, instrument, order, judgment or decree to which the Purchaser is subject that
would materially impact its ability to perform its obligations hereunder. 
 C. Investment Representations. 

(i) The Purchaser is acquiring the Private Placement Warrants and, upon exercise of the Private Placement Warrants, the Shares issuable upon
such exercise (collectively, the “Securities”), for the Purchaser’s own account, for investment purposes only and not with a view towards, or for resale in connection with, any public sale or distribution thereof. 

(ii) The Purchaser is an “accredited investor” as such term is defined in Rule 501(a)(3) of Regulation D of the Securities Act of
1933, as amended (the “Securities Act”). 
 (iii) The Purchaser understands that the Securities are being offered and will
be sold to it in reliance on specific exemptions from the registration requirements of the United States federal and state securities laws and that the Company is relying upon the truth and accuracy of, and the Purchaser’s compliance with, the
representations and warranties of the Purchaser set forth herein in order to determine the availability of such exemptions and the eligibility of the Purchaser to acquire such Securities. 

(iv) The Purchaser did not enter into this Agreement as a result of any general solicitation or general advertising within the meaning of
Rule 502(c) under the Securities Act. 

  
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 (v) The Purchaser has been furnished with all materials relating to the business, finances
and operations of the Company and materials relating to the offer and sale of the Securities which have been requested by the Purchaser. The Purchaser has been afforded the opportunity to ask questions of the executive officers and directors of the
Company. The Purchaser understands that its investment in the Securities involves a high degree of risk and it has sought such accounting, legal and tax advice as it has considered necessary to make an informed investment decision with respect to
the acquisition of the Securities. 
 (vi) The Purchaser understands that no United States federal or state agency or any other government
or governmental agency has passed on or made any recommendation or endorsement of the Securities or the fairness or suitability of the investment in the Securities by the Purchaser nor have such authorities passed upon or endorsed the merits of the
offering of the Securities. 
 (vii) The Purchaser understands that: (a) the Securities have not been and are not being registered
under the Securities Act or any state securities laws, and may not be offered for sale, sold, assigned or transferred unless (1) subsequently registered thereunder or (2) sold in reliance on an exemption therefrom; and (b) except as
specifically set forth in the Registration and Stockholder Rights Agreement, neither the Company nor any other person is under any obligation to register the Securities under the Securities Act or any state securities laws or to comply with the
terms and conditions of any exemption thereunder. While the Purchaser understands that Rule 144 under the Securities Act is not available for the resale of securities initially issued by shell companies (other than business combination related shell
companies) or issuers that have been at any time previously a shell company, the Purchaser understands that Rule 144 includes an exception to this prohibition if the following conditions are met: (i) the issuer of the securities that was
formerly a shell company has ceased to be a shell company; (ii) the issuer of the securities is subject to the reporting requirements of Section 13 or 15(d) of the Securities Exchange Act of 1934, as amended (the “Exchange
Act”); (iii) the issuer of the securities has filed all Exchange Act reports and material required to be filed, as applicable, during the preceding 12 months (or such shorter period that the issuer was required to file such reports and
materials), other than Form 8-K reports; and (iv) at least one year has elapsed from the time that the issuer filed current Form 10 type information with the SEC reflecting its status as an entity that is
not a shell company. 
 (viii) The Purchaser has knowledge and experience in financial and business matters, understands the high degree of
risk associated with investments in the securities of companies in the development stage such as the Company, is capable of evaluating the merits and risks of an investment in the Securities and is able to bear the economic risk of an investment in
the Securities in the amount contemplated hereunder for an indefinite period of time. The Purchaser has adequate means of providing for its current financial needs and contingencies and will have no current or anticipated future needs for liquidity
which would be jeopardized by the investment in the Securities. The Purchaser can afford a complete loss of its investment in the Securities. 

  
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 Section 4. Conditions of the Purchaser’s
Obligations. The obligations of the Purchaser to purchase and pay for the Private Placement Warrants are subject to the fulfillment, on or before each Closing Date, of each of the following conditions: 

A. Representations and Warranties. The representations and warranties of the Company contained in Section 2 shall be true and
correct at and as of such Closing Date as though then made. 
 B. Performance. The Company shall have performed and complied with all
agreements, obligations and conditions contained in this Agreement that are required to be performed or complied with by it on or before such Closing Date. 

C. No Injunction. No litigation, statute, rule, regulation, executive order, decree, ruling or injunction shall have been enacted,
entered, promulgated or endorsed by or in any court or governmental authority of competent jurisdiction or any self-regulatory organization having authority over the matters contemplated hereby, which prohibits the consummation of any of the
transactions contemplated by this Agreement or the Private Warrant Agreement. 
 D. Private Warrant Agreement and Registration and
Stockholder Rights Agreement. The Company shall have entered into a Private Warrant Agreement with a warrant agent and the Registration and Stockholder Rights Agreement, each on terms satisfactory to the Purchaser. 

E. Corporate Consents. The Company shall have obtained the consent of its Board of Directors authorizing the execution, delivery and
performance of this Agreement and the Private Warrant Agreement and the issuance and sale of the Private Placement Warrants hereunder. 

Section 5. Conditions of the Company’s Obligations. The obligations of the Company to the
Purchaser under this Agreement are subject to the fulfillment, on or before each Closing Date, of each of the following conditions: 
 A.
Representations and Warranties. The representations and warranties of the Purchaser contained in Section 3 shall be true and correct at and as of such Closing Date as though then made. 

B. Performance. The Purchaser shall have performed and complied with all agreements, obligations and conditions contained in this
Agreement that are required to be performed or complied with by the Purchaser on or before such Closing Date. 
 C. Corporate
Consents. The Company shall have obtained the consent of its Board of Directors authorizing the execution, delivery and performance of this Agreement and the Private Warrant Agreement and the issuance and sale of the Private Placement Warrants
hereunder. 
 D. No Injunction. No litigation, statute, rule, regulation, executive order, decree, ruling or injunction shall have
been enacted, entered, promulgated or endorsed by or in any court or governmental authority of competent jurisdiction or any self-regulatory organization having authority over the matters contemplated hereby, which prohibits the consummation of any
of the transactions contemplated by this Agreement or the Private Warrant Agreement. 

  
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 E. Private Warrant Agreement. The Company shall have entered into a Private Warrant
Agreement with a warrant agent on terms satisfactory to the Company. 
 Section 6. Termination. This
Agreement may be terminated at any time after December 31, 2021 upon the election by either the Company or the Purchaser upon written notice to the other party if the closing of the Public Offering does not occur prior to such date. 

Section 7. Survival of Representations and Warranties. All of the representations and warranties
contained herein shall survive each Closing Date. 
 Section 8. Definitions. Terms used but not
otherwise defined in this Agreement shall have the meaning assigned to such terms in the registration statement on Form S-1 the Company has filed with the Securities and Exchange Commission under the
Securities Act in connection with the Public Offering. 
 Section 9. Miscellaneous. 

A. Successors and Assigns. Except as otherwise expressly provided herein, all covenants and agreements contained in this Agreement by
or on behalf of any of the parties hereto shall bind and inure to the benefit of the respective successors of the parties hereto whether so expressed or not. Notwithstanding the foregoing or anything to the contrary herein, the parties may not
assign this Agreement without the prior written consent of the other party hereto, other than assignments by the Purchaser to its affiliates (including, without limitation, one or more of its members). 

B. Severability. Whenever possible, each provision of this Agreement shall be interpreted in such manner as to be effective and valid
under applicable law, but if any provision of this Agreement is held to be prohibited by or invalid under applicable law, such provision shall be ineffective only to the extent of such prohibition or invalidity, without invalidating the remainder of
this Agreement. 
 C. Counterparts. This Agreement may be executed simultaneously in two or more counterparts, none of which needs to
contain the signatures of more than one party, but all such counterparts taken together shall constitute one and the same agreement. In the event that any signature is delivered by facsimile transmission or by
e-mail delivery of a “pdf” format data file, such signature shall create a valid and binding obligation of the party executing (or on whose behalf such signature is executed) with the same force and
effect as if such facsimile or “.pdf” signature page were an original thereof. 
 D. Descriptive Headings; Interpretation.
The descriptive headings of this Agreement are inserted for convenience only and do not constitute a substantive part of this Agreement. The use of the word “including” in this Agreement shall be by way of example rather than by
limitation. 
 E. Governing Law. This Agreement shall be deemed to be a contract made under the laws of the State of New York and for
all purposes shall be construed in accordance with the internal laws of the State of New York, without regard to the conflicts of laws principles thereof. 

  
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 F. Amendments. This Agreement may not be amended, modified or waived as to any
particular provision, except by a written instrument executed by all parties hereto. 
 [Signature Page Follows] 

  
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 IN WITNESS WHEREOF, the parties hereto have executed this Agreement to be effective
as of the date first set forth above. 
  

			
	COMPANY:
	
	M3-BRIGADE ACQUISITION III CORP., a Delaware corporation
		
	 By:
	 	/s/ Mohsin Meghji
		 	Name: Mohsin Meghji
		 	Title: Executive Chairman of the Board of Directors


  

			
	PURCHASER:
	
	M3-BRIGADE SPONSOR III LP, a Delaware limited partnership
	
	By: M3-Brigade Acquisition Partners III Corp., its general partner
		
	 By:
	 	/s/ Mohsin Meghji
	Name: Mohsin Meghji
	Title: Authorized Person


 [Signature Page to Private Placement Warrants Purchase Agreement]