Exhibit 10.5


 


PIONEER MERGER CORP.


660 Madison Avenue


New York, NY 10065


 


January 12, 2021


 


Pioneer Merger Sponsor LLC


660 Madison Avenue


New York, NY 10065


 


Ladies and Gentlemen:


 


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 Pioneer Merger Corp. (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”), Pioneer Merger Sponsor LLC (the “Sponsor”) shall take steps directly or indirectly
to 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 660 Madison Avenue, New York, NY 10065 (or any successor location). In exchange therefor the Company
shall pay the Sponsor a sum of $10,000 per month on the Effective Date and continuing monthly thereafter until the Termination
Date. The Sponsor hereby agrees that it does not have any right, title, interest or claim of any kind (a “Claim”)
in or to any monies that may be set aside in a trust account (the “Trust Account”) that may be established
upon the consummation of the IPO and hereby irrevocably waives any Claim it may have in the future as a result of, or arising out
of, any negotiations, contracts or agreements with the Company and will not seek recourse against the Trust Account for any reason
whatsoever.


 


This letter agreement constitutes the entire agreement and understanding
of the parties hereto in respect of its subject matter and supersedes all prior understandings, agreements or representations by
or between the parties hereto, written or oral, to the extent they relate in any way to the subject matter hereof or the transactions
contemplated hereby.


 


This letter agreement may not be amended, modified or waived
as to any particular provision, except by a written instrument executed by the parties hereto.


 


The parties may not assign this letter agreement and any of
their rights, interests or obligations hereunder without the consent of the other party.


 


This letter agreement shall be governed by, construed in accordance
with, and interpreted pursuant to the laws of the State of New York, without giving effect to its choice of laws principles that
might apply the laws of another jurisdiction.


This letter agreement may be executed in one or more counterparts,
each of which shall for all purposes be deemed to be an original but all of which together shall constitute one and the same agreement.
Only one such counterpart signed by the party against whom enforceability is sought needs to be produced to evidence the existence
of this letter agreement.


 


[Signature Page Follows]


 






     


     


    

 


	 	Very truly yours,
	 	 
	 	PIONEER MERGER  CORP.
	 	 	 
	 	By:	
        /s/ Scott Carpenter

	 	Name:	Scott Carpenter
	 	Title:	Chief Operating Officer


 


	
        AGREED TO AND ACCEPTED BY:
	 
	 	 
	PIONEER MERGER SPONSOR LLC	 
	 	 	 
	By:	
        /s/ Scott Carpenter
	 
	Name:	Scott Carpenter	 
	Title:	Chief Operating Officer	 


 


[Signature Page to Administrative Services
Agreement]