EX-4.1





 Exhibit 4.1 

SPECIMEN UNIT CERTIFICATE 

NUMBER UNITS U- 
  

			
	 SEE REVERSE FOR
 CERTAIN DEFINITIONS
	  	

 M3-Brigade Acquisition III Corp. 

CUSIP 
 UNITS CONSISTING
OF ONE SHARE OF CLASS A COMMON STOCK AND ONE-THIRD OF ONE REDEEMABLE PUBLIC WARRANT, EACH WHOLE PUBLIC WARRANT ENTITLING THE HOLDER TO PURCHASE ONE SHARE OF CLASS A COMMON STOCK 

THIS CERTIFIES THAT _________________is the owner of ______Units. 

Each unit (“Unit”) consists of one (1) share of Class A common stock, par value $0.0001 per share (“Common
Stock”), of M3-Brigade Acquisition III Corp., a Delaware corporation (the “Company”), and one-third (1/3) of one redeemable public warrant (each whole
public warrant, a “Public Warrant”). Each Public Warrant entitles the holder to purchase one (1) share of Common Stock for $11.50 per stock (subject to adjustment). Each whole Public Warrant will become exercisable thirty
(30) days after the Company’s completion of a merger, stock exchange, asset acquisition, stock purchase, reorganization or other similar business combination with one or more businesses (each, a “Business Combination”), and will
expire unless exercised before 5:00 p.m., New York City Time, on the date that is five (5) years after the date on which the Company completes its initial Business Combination, or earlier upon redemption or liquidation (the “Expiration
Date”). The Common Stock and Public Warrants comprising the Units represented by this certificate are not transferable separately prior to _______________, 2021, unless Cantor Fitzgerald & Co. elects to allow earlier separate trading,
subject to the Company’s filing with the Securities and Exchange Commission of a Current Report on Form 8-K containing an audited balance sheet reflecting the Company’s receipt of the gross proceeds
of the initial public offering and issuing a press release announcing when separate trading will begin. No fractional Public Warrants will be issued upon separation of the Units, and only whole Public Warrants are exercisable. The terms of the
Public Warrants are governed by the Public Warrant Agreement, dated as of    [_______________], 2021 (as amended, supplemented or otherwise modified from time to time, the “Public Warrant Agreement”), between the
Company and Continental Stock Transfer & Trust Company, as warrant agent (in such capacity, the “ Warrant Agent”), and are subject to the terms and provisions contained therein, all of which terms and provisions the holder of this
certificate consents to by acceptance hereof. Copies of the Public Warrant Agreement are on file at the office of the Warrant Agent at 1 State Street, 30th Floor, New York, New York 10004, and are available to any holder of the Public Warrants on
written request and without cost. 
 The Units represented by this certificate will automatically separate into the Class A Common
Stock and Public Warrants comprising such Units after completion of a Business Combination. 
 This certificate is not valid unless
countersigned by the transfer agent and registered by the registrar of the Company. 












 This certificate shall be governed by and construed in accordance with the internal laws of
the State of New York. Witness the facsimile signatures of its duly authorized officers. 
  

					
	By	 		  	
			
	 

         
	 		  	              

	Chief Executive Officer	 		  	Transfer Agent













 M3-Brigade Acquisition III Corp. 

The Company will furnish without charge to each unitholder who so requests, a statement of the powers, designations, preferences and relative,
participating, optional or other special rights of each class of stocks or series thereof of the Company and the qualifications, limitations or restrictions of such preferences and/or rights. 

The following abbreviations, when used in the inscription on the face of this certificate, shall be construed as though they were written out
in full according to applicable laws or regulations: 
  

			
	TEN COM    —    as tenants in common	  	 UNIF GIFT MIN — Custodian

ACT

	TEN ENT     —    as tenants by the entireties	  	 

                      
          

		  	(Cust)(Minor)
		
	JT TEN         —    as joint tenants with right of survivorship and not as tenants in common	  	 Under Uniform Gifts to Minors Act

		  	              

		  	(State)

 Additional abbreviations may also be used though not in the above list. 












 For value received,     hereby sells, assigns and transfers unto 

(PLEASE INSERT SOCIAL SECURITY OR OTHER IDENTIFYING NUMBER(S) OF ASSIGNEE(S)) 

(PLEASE PRINT OR TYPEWRITE NAME(S) AND ADDRESS(ES), INCLUDING ZIP CODE, OF ASSIGNEE(S)) 

Units represented by the within certificate, and does hereby irrevocably constitute and appoint ______ Attorney to transfer the said Units on
the books of the within named Company with full power of substitution in the premises. 

Dated                         
                                         
                               

 

			
		 	              

		 	Notice: The signature(s) to this assignment must correspond with the name as written upon the face of the certificate in every particular, without alteration or enlargement or any change
whatever.

  

			
	Signature(s) Guaranteed:	 	
		
	              
	 	
	THE SIGNATURE(S) MUST BE GUARANTEED BY AN ELIGIBLE GUARANTOR INSTITUTION (BANKS, STOCKBROKERS, SAVINGS AND LOAN ASSOCIATIONS AND CREDIT UNIONS WITH MEMBERSHIP IN AN APPROVED SIGNATURE GUARANTEE MEDALLION PROGRAM, PURSUANT TO S.E.C.
RULE 17Ad-15 UNDER THE SECURITIES EXCHANGE ACT OF 1934, AS AMENDED (OR ANY SUCCESSOR RULE).	 	

 As more fully described in, and subject to the terms and conditions described in, the Company’s final prospectus for its
initial public offering, dated [    ], 2021, the holder(s) of this certificate shall be entitled to receive a pro rata portion of certain funds held in the trust account established in connection with the Company’s initial
public offering only in the event that (i) the Company redeems the shares of Common Stock sold in its initial public offering and liquidates because it does not consummate an initial business combination within the period of time set forth in
the Company’s amended and restated certificate of incorporation, (as the same may be further amended, supplemented or otherwise modified from time to time, the “amended and restated certificate of incorporation” (ii) the Company
redeems the shares of Common Stock sold in its initial public offering in connection with a stockholder vote to amend the Company’s amended and restated certificate of incorporation (A) that would modify the substance or timing of the
Company’s obligation to provide holders of the Common Stock the right to have their stock redeemed in connection with the Company’s initial business combination or to redeem 100% of the Common Stock if the Company does not complete its
initial business combination within the time period set forth therein or (B) with respect to any other provision relating to the rights of holders of the Common Stock, or (iii) if the holder(s) seek(s) to redeem for cash his, her or its
respective shares of Common Stock in connection with a tender offer (or proxy solicitation, solely in the event the Company seeks stockholder approval of the proposed initial business combination) setting forth the details of a proposed initial
business combination. In no other circumstances shall the holder(s) have any right or interest of any kind in or to the trust account.