EX-10.2





 Exhibit 10.2 

INVESTMENT MANAGEMENT TRUST AGREEMENT 

This Investment Management Trust Agreement (this “Agreement”) is made effective as of October 21, 2021, by and
between M3-Brigade Acquisition III Corp., a Delaware corporation (the “Company”), and Continental Stock Transfer & Trust Company, a New York limited purpose trust company (the
“Trustee”). 
 WHEREAS, the Company’s registration statement on Form
S-1, File No. 333-256017 (the “Registration Statement”) and prospectus (the “Prospectus”) for the initial public
offering of the Company’s units (the “Units”), each of which consists of one share of the Company’s Class A common stock, par value $0.0001 per share (the “Common Stock”), and one-third of one redeemable public warrant, each whole public warrant entitling the holder thereof to purchase one share of Common Stock (such initial public offering hereinafter referred to as the
“Offering”), has been declared effective as of the date hereof by the U.S. Securities and Exchange Commission; and WHEREAS, the Company has entered into an Underwriting Agreement (the “Underwriting
Agreement”) with Cantor Fitzgerald & Co. as the representative (the “Representative”) of the several underwriters (the “Underwriters”) named therein; and WHEREAS, as described in
the Prospectus, $263,610,000 of the gross proceeds of the Offering and sale of the Private Placement Warrants (as defined in the Underwriting Agreement) (or $303,151,500, if the Underwriters’ over-allotment option is exercised in full) will be
delivered to the Trustee to be deposited and held in a segregated trust account located at all times in the United States (the “Trust Account”) for the benefit of the Company and the holders of the Common Stock included in
the Units issued in the Offering as hereinafter provided (the amount to be delivered to the Trustee (and any interest subsequently earned thereon) is referred to herein as the “Property,” the stockholders for whose benefit
the Trustee shall hold the Property will be referred to as the “Public Stockholders,” and the Public Stockholders and the Company will be referred to together as the “Beneficiaries”); and WHEREAS, the
Company and the Trustee desire to enter into this Agreement to set forth the terms and conditions pursuant to which the Trustee shall hold the Property. 

NOW THEREFORE, IT IS AGREED: 
 1.
Agreements and Covenants of Trustee. The Trustee hereby agrees and covenants to: 
 (a) Hold the Property in trust for the Beneficiaries in
accordance with the terms of this Agreement in the Trust Account established by the Trustee in the United States at J.P. Morgan Chase Bank, N.A., maintained by the Trustee and at a brokerage institution selected by the Trustee that is reasonably
satisfactory to the Company; 
 (b) Manage, supervise and administer the Trust Account subject to the terms and conditions set forth herein;













 (c) In a timely manner, upon the written instruction of the Company, invest and reinvest the
Property solely in United States government securities within the meaning of Section 2(a)(16) of the Investment Company Act of 1940, as amended, having a maturity of 185 days or less, or in money market funds meeting the conditions of Rule 2a-7(d) promulgated under the Investment Company Act of 1940, as amended (or any successor rule), which invest only in direct U.S. government treasury obligations, as determined by the Company; it being understood
that the Trust Account will earn no interest while account funds are uninvested awaiting the Company’s instructions hereunder; and while account funds are invested or uninvested, the Trustee may earn bank credits or other consideration;
(d) Collect and receive, when due, all interest or other income arising from the Property, which shall become part of the “Property,” as such term is used herein; 

(d) Promptly notify the Company and the Representative of all communications received by the Trustee with respect to any Property requiring
action by the Company; 
 (e) Supply any necessary information or documents as may be requested by the Company (or its authorized agents) in
connection with the Company’s preparation of the tax returns relating to assets held in the Trust Account; 
 (f) Participate in any
plan or proceeding for protecting or enforcing any right or interest arising from the Property if, as and when instructed by the Company to do so; 

(g) Render to the Company monthly written statements of the activities of, and amounts in, the Trust Account reflecting all receipts and
disbursements of the Trust Account; 
 (h) Commence liquidation of the Trust Account only after and promptly after (x) receipt of, and
only in accordance with, the terms of a letter from the Company (“Termination Letter”) in a form substantially similar to that attached hereto as either Exhibit A or Exhibit B, as applicable, signed on behalf of
the Company by its Chief Executive Officer, Chief Financial Officer, President, Executive Vice President, Vice President, Secretary or Chairman of the board of directors of the Company (the “Board”) or other authorized
officer of the Company, and, in the case of a Termination Letter in a form substantially similar to the attached hereto as Exhibit A, acknowledged and agreed to by the Representative, and complete the liquidation of the Trust Account and
distribute the Property in the Trust Account, including interest earned on the funds held in the Trust Account and not previously released to the Company to pay its working capital expenses as well as to pay its taxes (less up to $100,000 of
interest that may be released to the Company to pay dissolution expenses and which interest shall be net of taxes payable), only as directed in the Termination Letter and the other documents referred to therein, or (y) the date which is the
later of (1) 12 months from the closing of the offering, (ii) such later date as provided by Section 9.1(c) of the Company’s amended and restated certificate of incorporation and (3) such other time period in which the Company
must consummate an initial business combination pursuant to an amendment to its amended and restated certificate of incorporation, if a Termination Letter has not been received by the Trustee prior to such date, in which case the Trust Account shall
be liquidated in accordance with the procedures set forth in the Termination Letter attached 

  
 2 













 
as Exhibit B and the Property in the Trust Account, including interest earned on the funds held in the Trust Account and not previously released to the Company to pay its working capital
requirements as well as to pay its taxes (less up to $100,000 of interest that may be released to the Company to pay dissolution expenses and which interest shall be net of taxes payable) shall be distributed to the Public Stockholders of record as
of such date; 
 (i) Upon written request from the Company, which may be given from time to time in a form substantially similar to that
attached hereto as Exhibit C, withdraw from the Trust Account and distribute to the Company the amount of interest earned on the Property requested by the Company to cover its working capital expenses or any tax obligation owed by the Company
as a result of assets of the Company or interest or other income earned on the Property, which amount shall be delivered directly to the Company by electronic funds transfer or other method of prompt payment, and the Company shall forward such
payment to the relevant taxing authority; provided, however, that to the extent there is not sufficient cash in the Trust Account to pay such tax obligation, the Trustee shall liquidate such assets held in the Trust Account as shall be
designated by the Company in writing to make such distribution, so long as there is no reduction in the principal amount per share initially deposited in the Trust Account; provided, further, that if the tax to be paid is a franchise
tax, the written request by the Company to make such distribution shall be accompanied by a copy of the franchise tax bill from the State of Delaware for the Company (it being acknowledged and agreed that any such amount in excess of interest income
earned on the Property shall not be payable from the Trust Account). The written request of the Company referenced above shall constitute presumptive evidence that the Company is entitled to said funds, and the Trustee shall have no responsibility
to look beyond said request; 
 (j) Upon written request from the Company, which may be given from time to time in a form substantially
similar to that attached hereto as Exhibit D, the Trustee shall distribute on behalf of the Company the amount requested by the Company to be used to redeem shares of Common Stock from Public Stockholders properly submitted in connection with
a stockholder vote to approve an amendment to the Company’s amended and restated certificate of incorporation to modify the substance or timing of the ability of Public Stockholders to seek redemption in connection with an initial Business
Combination or amendments to the Company’s amended and restated certificate of incorporation prior thereto or the Company’s obligation to redeem 100% of its public shares of Common Stock if the Company has not consummated an initial
Business Combination within such time as is described in clause (y) of Section 1(i) of the Agreement. The written request of the Company referenced above shall constitute presumptive evidence that the Company is entitled to distribute said
funds, and the Trustee shall have no responsibility to look beyond said request; and 
 (k) Not make any withdrawals or distributions from
the Trust Account other than pursuant to 1(i), (j) or (k) above. 

  
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 2. Agreements and Covenants of the Company. The Company hereby agrees and covenants to: 

(a) Give all instructions to the Trustee hereunder in writing, signed by the Company’s Chairman of the Board, Chief Executive Officer,
Chief Financial Officer, President, Executive Vice President, Vice President or Secretary. In addition, except with respect to its duties under 1(i), (j) and (k) hereof, the Trustee shall be entitled to rely on, and shall
be protected in relying on, any verbal or telephonic advice or instruction which it, in good faith and with reasonable care, believes to be given by any one of the persons authorized above to give written instructions, provided that the Company
shall promptly confirm such instructions in writing; 
 (b) Subject to Section 4 hereof, hold the Trustee harmless
and indemnify the Trustee from and against any and all expenses, including reasonable counsel fees and disbursements, or losses suffered by the Trustee in connection with any action taken by it hereunder and in connection with any action, suit or
other proceeding brought against the Trustee involving any claim, or in connection with any claim or demand, which in any way arises out of or relates to this Agreement, the services of the Trustee hereunder, or the Property or any interest earned
on the Property, except for expenses and losses resulting from the Trustee’s gross negligence, fraud or willful misconduct. Promptly after the receipt by the Trustee of notice of demand or claim or the commencement of any action, suit or
proceeding, pursuant to which the Trustee intends to seek indemnification under this Section 2(b), it shall notify the Company in writing of such claim (hereinafter referred to as the “Indemnified
Claim”). The Trustee shall have the right to conduct and manage the defense against such Indemnified Claim; provided that the Trustee shall obtain the consent of the Company with respect to the selection of counsel, which consent
shall not be unreasonably withheld. The Trustee may not agree to settle any Indemnified Claim without the prior written consent of the Company, which such consent shall not be unreasonably withheld. The Company may participate in such action with
its own counsel; 
 (c) Pay the Trustee the fees set forth on Schedule A hereto, including an initial acceptance fee, annual
administration fee, and transaction processing fee which fees shall be subject to modification by the parties from time to time. It is expressly understood that the Property shall not be used to pay such fees unless and until the closing of the
Business Combination (defined below). The Company shall pay the Trustee the initial acceptance fee and the first annual administration fee at the consummation of the Offering. The Company shall not be responsible for any other fees or charges of the
Trustee except as set forth in this Section 2(c), Schedule A and as may be provided in Section 2(b) hereof; 

(d) In connection with any vote of the Company’s stockholders regarding a merger, capital stock exchange, asset acquisition, stock
purchase, reorganization or similar business combination involving the Company and one or more businesses (the “Business Combination”), provide to the Trustee an affidavit or certificate of the inspector of elections for the
stockholder meeting verifying the vote of such stockholders regarding such Business Combination; 

  
 4 













 (e) Provide the Representative with a copy of any Termination Letter(s) and/or any other
correspondence that is sent to the Trustee with respect to any proposed withdrawal from the Trust Account promptly after it issues the same; and 

(f) Instruct the Trustee to make only those distributions that are permitted under this Agreement, and refrain from instructing the Trustee to
make any distributions that are not permitted under this Agreement. 
 3. Limitations of Liability. The Trustee shall have no responsibility
or liability to: 
 (a) Imply obligations, perform duties, inquire or otherwise be subject to the provisions of any agreement or document
other than this Agreement and that which is expressly set forth herein; 
 (b) Take any action with respect to the Property, other than as
directed in Section 1 hereof, and the Trustee shall have no liability to any third party except for liability arising out of the Trustee’s gross negligence, fraud or willful misconduct; 

(c) Institute any proceeding for the collection of any principal and income arising from, or institute, appear in or defend any proceeding of
any kind with respect to, any of the Property unless and until it shall have received instructions from the Company given as provided herein to do so and the Company shall have advanced or guaranteed to it funds sufficient to pay any expenses
incident thereto; 
 (d) Refund any depreciation in principal of any Property; 

(e) Assume that the authority of any person designated by the Company to give instructions hereunder shall not be continuing unless provided
otherwise in such designation, or unless the Company shall have delivered a written revocation of such authority to the Trustee; 
 (f) The
other parties hereto or to anyone else for any action taken or omitted by it, or any action suffered by it to be taken or omitted, in good faith and in the Trustee’s best judgment, except for the Trustee’s gross negligence, fraud or
willful misconduct. The Trustee may rely conclusively and shall be protected in acting upon any order, notice, demand, certificate, opinion or advice of counsel (including counsel chosen by the Trustee, which counsel may be the Company’s
counsel), statement, instrument, report or other paper or document (not only as to its due execution and the validity and effectiveness of its provisions, but also as to the truth and acceptability of any information therein contained) which the
Trustee believes, in good faith and with reasonable care, to be genuine and to be signed or presented by the proper person or persons. The Trustee shall not be bound by any notice or demand, or any waiver, modification, termination or rescission of
this Agreement or any of the terms hereof, unless evidenced by a written instrument delivered to the Trustee, signed by the proper party or parties and, if the duties or rights of the Trustee are affected, unless it shall give its prior written
consent thereto; 

  
 5 













 (g) Verify the accuracy of the information contained in the Registration Statement; 

(h) Provide any assurance that any Business Combination entered into by the Company or any other action taken by the Company is as
contemplated by the Registration Statement; 
 (i) File information returns with respect to the Trust Account with any local, state or
federal taxing authority or provide periodic written statements to the Company documenting the taxes payable by the Company, if any, relating to any interest income earned on the Property; 

(j) Prepare, execute and file tax reports, income or other tax returns and pay any taxes with respect to any income generated by, and
activities relating to, the Trust Account, regardless of whether such tax is payable by the Trust Account or the Company, including, but not limited to, any tax obligations, except pursuant to Section 1(j) hereof; or 

(k) Verify calculations, qualify or otherwise approve the Company’s written requests for distributions pursuant to 1(i),
(j) or (k) hereof. 
 4. Trust Account Waiver. The Trustee has no right of
set-off or any right, title, interest or claim of any kind (“Claim”) to, or to any monies in, the Trust Account, and hereby irrevocably waives any Claim to, or to any monies in, the
Trust Account that it may have now or in the future. In the event the Trustee has any Claim against the Company under this Agreement, including, without limitation, under 2(b) or (c) hereof, the Trustee shall pursue such Claim solely against
the Company and its assets outside the Trust Account and not against the Property or any monies in the Trust Account. 
 5. Termination.
This Agreement shall terminate as follows: 
 (a) If the Trustee gives written notice to the Company that it desires to resign under this
Agreement, the Company shall use its reasonable efforts to locate a successor trustee, pending which the Trustee shall continue to act in accordance with this Agreement. At such time that the Company notifies the Trustee that a successor trustee has
been appointed and has agreed to become subject to the terms of this Agreement, the Trustee shall transfer the management of the Trust Account to the successor trustee, including but not limited to the transfer of copies of the reports and
statements relating to the Trust Account, whereupon this Agreement shall terminate; provided, however, that in the event that the Company does not locate a successor trustee within ninety (90) days of receipt of the resignation
notice from the Trustee, the Trustee may submit an application to have the Property deposited with any court in the State of New York or with the United States District Court for the Southern District of New York and upon such deposit, the Trustee
shall be immune from any liability whatsoever; or 

  
 6 













 (b) At such time that the Trustee has completed the liquidation of the Trust Account and its
obligations in accordance with the provisions of Section 1(i) hereof (which section may not be amended under any circumstances) and distributed the Property in accordance with the provisions of the Termination Letter, this
Agreement shall terminate except with respect to Section 2(b). 
 6. Miscellaneous. 

(a) The Company and the Trustee each acknowledge that the Trustee will follow the security procedures set forth below with respect to funds
transferred from the Trust Account. The Company and the Trustee will each restrict access to confidential information relating to such security procedures to authorized persons. Each party must notify the other party immediately if it has reason to
believe unauthorized persons may have obtained access to such confidential information, or of any change in its authorized personnel. In executing funds transfers, the Trustee shall rely upon all information supplied to it by the Company, including,
account names, account numbers, and all other identifying information relating to a Beneficiary, Beneficiary’s bank or intermediary bank. Except for any liability arising out of the Trustee’s gross negligence, fraud or willful misconduct,
the Trustee shall not be liable for any loss, liability or expense resulting from any error in the information or transmission of the funds. 

(b) This Agreement shall be governed by and construed and enforced in accordance with the laws of the State of New York, without giving effect
to conflicts of law principles that would result in the application of the substantive laws of another jurisdiction. This Agreement may be executed in several original or facsimile counterparts, each one of which shall constitute an original, and
together shall constitute but one instrument. 
 (c) This Agreement contains the entire agreement and understanding of the parties hereto
with respect to the subject matter hereof. Subject to Section 6(d) hereof, this Agreement or any provision hereof may only be changed, amended or modified (other than to correct a typographical error) by a writing signed by each of the parties
hereto; provided, however, that no such change, amendment or modification to 1(i), 2(f) or Exhibit A may be made without the prior written consent of the Representative. 

(d) This Agreement or any provision hereof may only be changed, amended or modified pursuant to Section 6(c) hereof
with the Consent of the Stockholders. For purposes of this Section 6(d), the “Consent of the Stockholders” means receipt by the Trustee of a certificate from the inspector of elections of the
stockholder meeting certifying that the Company’s stockholders of record as of a record date established in accordance with Section 213(a) of the Delaware General Corporation Law, as amended (“DGCL”) (or any
successor rule), who hold sixty-five percent (65%) or more of all then outstanding shares of the Common Stock and Class B common stock, par value $0.0001 per share, of the Company voting together as a single class, have voted in favor of such
change, amendment or modification. No such amendment will affect any Public Stockholder who has otherwise indicated his election to redeem his shares of Common Stock in connection with a stockholder vote sought to amend this Agreement to modify the
substance or timing of the Company’s obligation to redeem 100% of the Common Stock if the Company does not complete its initial Business Combination 

  
 7 













 
within the time frame specified in the Company’s amended and restated certificate of incorporation. Except for any liability arising out of the Trustee’s gross negligence, fraud or
willful misconduct, the Trustee may rely conclusively on the certification from the inspector or elections referenced above and shall be relieved of all liability to any party for executing the proposed amendment in reliance thereon. 

(e) The parties hereto consent to the jurisdiction and venue of any state or federal court located in the City of New York, State of New York,
for purposes of resolving any disputes hereunder. AS TO ANY CLAIM, CROSS-CLAIM OR COUNTERCLAIM IN ANY WAY RELATING TO THIS AGREEMENT, EACH PARTY WAIVES THE RIGHT TO TRIAL BY JURY. 

(f) Any notice, consent or request to be given in connection with any of the terms or provisions of this Agreement shall be in writing and
shall be sent by express mail or similar private courier service, by certified mail (return receipt requested), by hand delivery or by electronic mail: 

if to the Trustee, to: 

Continental Stock Transfer & Trust Company 

1 State Street, 30th Floor 
 New
York, NY 10004 
 Attn: Francis Wolf and Celeste Gonzalez 

	 	Email:	 fwolf@continentalstock.com 



cgonzalez@continentalstock.com 

if to the Company, to: 
 Mohsin Y.
Meghji 
 Executive Chairman of the Board of Directors 

1700 Broadway – 19th Floor 

New York, NY 10019 
 in each case,
with copies to: 
 Paul, Weiss, Rifkind, Wharton & Garrison LLP 

1285 Avenue of the Americas 
 New
York, New York 10019 

	 	Attn:	 David Curtiss, Esq. 



	 	Tel:	 (212) 373-3000 



and 
 Cantor Fitzgerald &
Co. 
 499 Park Avenue 
 New
York, New York 10022 

	 	Attn:	 General Counsel 



	 	Fax	 No.: (212) 829-4708 



  
 8 













 and 

Ellenoff Grossman & Schole LLP 

1345 Avenue of the Americas 
 New
York, NY 10105 
 Attn: Stuart Neuhauser, Esq. 

Email: sneuhauser@egsllp.com 

(g) Each of the Company and the Trustee hereby represents that it has the full right and power and has been duly authorized to enter into this
Agreement and to perform its respective obligations as contemplated hereunder. The Trustee acknowledges and agrees that it shall not make any claims or proceed against the Trust Account, including by way of
set-off, and shall not be entitled to any funds in the Trust Account under any circumstance. 
 (h)
This Agreement is the joint product of the Trustee and the Company and each provision hereof has been subject to the mutual consultation, negotiation and agreement of such parties and shall not be construed for or against any party hereto. 

(i) This Agreement may be executed in any number of counterparts, each of which shall be deemed to be an original, but all such counterparts
shall together constitute one and the same instrument. Delivery of a signed counterpart of this Agreement by facsimile or electronic transmission shall constitute valid and sufficient delivery thereof. 

(j) Each of the Company and the Trustee hereby acknowledges and agrees that Cantor Fitzgerald & Co. on behalf of the Underwriters is
a third party beneficiary of this Agreement. 
 (k) Except as specified herein, no party to this Agreement may assign its rights or delegate
its obligations hereunder to any other person or entity. 
 [Signature Page Follows] 

  
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 IN WITNESS WHEREOF, the parties have duly executed this Investment Management Trust
Agreement as of the date first written above. 
  

					
	CONTINENTAL STOCK TRANSFER & TRUST COMPANY, as Trustee
		
	By:	 	/s/ Francis Wolf
		 	Name:	 	Francis Wolf
		 	Title:	 	Vice President


  

					
	 M3-BRIGADE ACQUISITION III

CORP.

		
	By:	 	/s/ Mohsin Meghji
		 	Name:	 	Mohsin Meghji
		 	Title:	 	Executive Chairman of the Board of Directors














 SCHEDULE A 
  

							
	 Fee ltem
	  	 Time and method of payment
	  	Amount	 
	Initial set-up fee.	  	Initial closing of Offering by wire transfer.	  	$	  3,500	 
	Trustee administration fee	  	Payable annually. First year fee payable, at initial closing of Offering by wire transfer, thereafter by wire transfer or check.	  	$	  10,000	 
	Transaction processing fee for disbursements to Company	  	Billed to Company following disbursement made to Company under Section I	  	$	  250	 
	Paying Agent services as required	  	Billed to Company upon delivery of service pursuant to Section l(i) and 1.(k)	  	 	Prevailing rates	 













 EXHIBIT A 

[Letterhead of Company] 

[Insert date] 
 Continental Stock
Transfer & Trust Company 
 1 State Street, 30th Floor 

New York, New York 10004 
 Attn: Francis Wolf and Celeste
Gonzalez 
 Re: Trust Account—Termination Letter 

Dear Mr. Wolf and Ms. Gonzalez: 

Pursuant to Section 1(i) of the Investment Management Trust Agreement between M3-Brigade
Acquisition III Corp. (the “Company”) and Continental Stock Transfer & Trust Company (the “Trustee”), dated as
of                , 2021 (the “Trust Agreement”), this is to advise you that the Company has entered into an agreement with (the
“Target Business”) to consummate a business combination with Target Business (the “Business Combination”) on or about [insert date]. The Company shall notify you at least
seventy-two (72) hours in advance of the actual date (or such shorter period as you may agree) of the consummation of the Business Combination (the “Consummation Date”).
Capitalized terms used but not defined herein shall have the meanings set forth in the Trust Agreement. 
 In accordance with the terms of
the Trust Agreement, we hereby authorize you to commence to liquidate all of the assets of the Trust Account and transfer the proceeds to a segregated account held by you on behalf of the Beneficiaries to the effect that, on the Consummation Date,
all of the funds held in the Trust Operating Account at J.P. Morgan Chase Bank, N.A.. will be immediately available for transfer to the account or accounts that the Company shall direct on the Consummation Date. It is acknowledged and agreed that
while the funds are on deposit in the trust operating account at J.P. Morgan Chase Bank, N.A. awaiting distribution, the Company will not earn any interest or dividends. 

On the Consummation Date, (i) counsel for the Company shall deliver to you written notification that the Business Combination has been
consummated, or will be consummated concurrently with your transfer of funds to the accounts as directed by the Company (the “Notification”) and (ii) the Company shall deliver to you (a) a certificate by the Chief
Executive Officer, Chief Financial Officer or Chairman, which verifies that the Business Combination has been approved by a vote of the Company’s stockholders, if a vote is held and (b) a joint written instruction signed by the Company and
the Representative with respect to the transfer of the funds held in the Trust Account, including payment of amounts owed to public stockholders who have properly exercised their redemption rights (the “Instruction Letter”).
You are hereby directed and authorized to transfer the funds held in the Trust Account immediately upon your receipt 

  
 A-1 













 
of the Notification and the Instruction Letter, in accordance with the terms of the Instruction Letter. In the event that certain deposits held in the Trust Account may not be liquidated by the
Consummation Date without penalty, you will notify the Company in writing of the same and the Company shall direct you as to whether such funds should remain in the Trust Account and be distributed after the Consummation Date to the Company. Upon
the distribution of all the funds, net of any payments necessary for reasonable unreimbursed expenses related to liquidating the Trust Account, your obligations under the Trust Agreement shall be terminated. 

In the event that the Business Combination is not consummated on the Consummation Date described in the notice thereof and we have not
notified you on or before the original Consummation Date of a new Consummation Date, then upon receipt by the Trustee of written instructions from the Company, the funds held in the Trust Account shall be reinvested as provided in Section 1(c)
of the Trust Agreement on the business day immediately following the Consummation Date as set forth in such notice as soon thereafter as possible. 
  

			
	 Very truly yours,

	
	 M3-Brigade Acquisition III Corp.

		
	By:	 	 
		 	 Name:

		 	 Title:



  

			
	Acknowledged & Agreed by:
	
	 Cantor Fitzgerald & Co.

		
	By:	 	 
		 	 Name:

		 	 Title:


  

  
 A-2 













 EXHIBIT B 

[Letterhead of Company] 

[Insert date] 
 Continental Stock
Transfer & Trust Company 
 1 State Street, 30th Floor New York, 

New York 10004 
 Attn: Francis Wolf and Celeste Gonzalez 

Re: Trust Account—Termination Letter 
 Dear
Mr. Wolf and Ms. Gonzalez: 
 Pursuant to Section 1(i) of the Investment Management Trust Agreement between M3-Brigade Acquisition III Corp. (the “Company”) and Continental Stock Transfer & Trust Company (the “Trustee”), dated as of, 2021 (the “Trust
Agreement”), this is to advise you that the Company has been unable to effect a business combination with a Target Business (the “Business Combination”) within the time frame specified in Section 1(i) of the
Trust Agreement. Capitalized terms used but not defined herein shall have the meanings set forth in the Trust Agreement. 
 In accordance
with the terms of the Trust Agreement, we hereby authorize you to liquidate all of the assets in the Trust Account and to transfer the total proceeds into a segregated account held by you on behalf of the Beneficiaries to await distribution to the
Public Stockholders. The Company has selected as the effective date for the purpose of determining when the Public Stockholders will be entitled to receive their share of the liquidation proceeds. You agree to be the Paying Agent of record and, in
your separate capacity as Paying Agent, agree to distribute said funds directly to the Company’s Public Stockholders in accordance with the terms of the Trust Agreement and the Amended and Restated Certificate of Incorporation of the Company.
Upon the distribution of all the funds, net of any payments necessary for reasonable unreimbursed expenses related to liquidating the Trust Account, your obligations under the Trust Agreement shall be terminated, except to the extent otherwise
provided in Section 1(j) of the Trust Agreement. 
  

			
	 Very truly yours,

	
	 M3-Brigade Acquisition III Corp.

		
	By:	 	 
		 	 Name:

		 	 Title:



 cc: Cantor Fitzgerald & Co. 

  
 B-1 













 EXHIBIT C 

[Letterhead of Company] 

[Insert date] 
 Continental Stock
Transfer & Trust Company 
 1 State Street, 30th Floor 

New York, New York 10004 
 Attn: Francis Wolf and Celeste Gonzalez

 Re: Trust Account—Withdrawal Instruction 
 Dear
Mr. Wolf and Ms. Gonzalez: 
 Pursuant to Section 1(j) of the Investment Management Trust Agreement
between M3-Brigade Acquisition III Corp. (the “Company”) and Continental Stock Transfer & Trust Company (the “Trustee”), dated as of, 2021 (the
“Trust Agreement”), the Company hereby requests that you deliver to the Company $                 of the interest
income earned on the Property as of the date hereof. Capitalized terms used but not defined herein shall have the meanings set forth in the Trust Agreement. 

The Company needs such funds to pay for its working capital expenses or for the tax obligations as set forth on the attached tax return or tax
statement. In accordance with the terms of the Trust Agreement, you are hereby directed and authorized to transfer (via wire transfer) such funds promptly upon your receipt of this letter to the Company’s operating account at: 

[WIRE INSTRUCTION INFORMATION] 
  

			
	 Very truly yours,

	
	 M3-Brigade Acquisition III Corp.

		
	By:	 	 
		 	 Name:

		 	 Title:



 cc: Cantor Fitzgerald & Co. 

  
 C-1 













 EXHIBIT D 

[Letterhead of Company] 

[Insert date] 
 Continental Stock
Transfer & Trust Company 
 1 State Street, 30th Floor 

New York, New York 10004 
 Attn: Francis Wolf and Celeste Gonzalez

 Re: Trust Account—Stockholder Redemption Withdrawal Instruction 

Dear Mr. Wolf and Ms. Gonzalez: 

Pursuant to Section 1(k) of the Investment Management Trust Agreement between
M3-Brigade Acquisition III Corp. (the “Company”) and Continental Stock Transfer & Trust Company (the “Trustee”), dated as of you deliver to the
redeeming Public Stockholders of the Company $ 
 , 2021 (the “Trust Agreement”), the Company hereby requests that
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 the Beneficiaries for distribution to the Stockholders who have requested redemption of their Common Stock.
Capitalized terms used but not defined herein shall have the meanings set forth in the Trust Agreement. 
 The Company needs such funds to
pay its Public Stockholders who have properly elected to have their shares of Common Stock redeemed by the Company in connection with a stockholder vote to approve an amendment to the Company’s amended and restated certificate of incorporation
to modify the substance or timing of the Company’s obligation to redeem 100% of public shares of Common Stock if the Company has not consummated an initial Business Combination within such time as is described in Section 1(i) of the Trust
Agreement. As such, you are hereby directed and authorized to transfer (via wire transfer) such funds promptly upon your receipt of this letter. 
  

			
	 Very truly yours,

	
	 M3-Brigade Acquisition III Corp.

		
	By:	 	 
		 	 Name:

		 	 Title:



 cc: Cantor Fitzgerald & Co. 

  
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