Exhibit 10.4


 


EXECUTION
VERSION


 


FirstMark
Horizon Acquisition Corp.


100
5th Ave, 3rd Floor


New
York, NY 10011


 


October
5, 2020


 


FirstMark
Capital LLC


100
5th Ave, 3rd Floor


New
York, NY 10011


 


Re:
Administrative Services Agreement


 


Gentlemen:


 


This
letter agreement by and between FirstMark Horizon Acquisition Corp., a Delaware corporation (the “Company”),
and FirstMark Capital LLC, a Delaware limited liability company (“FirstMark”), dated as of the date
hereof, will confirm our agreement that, commencing on the date the securities of the Company are first listed on the New York
Stock Exchange (the “Listing Date”) and continuing until the earlier of the consummation by the Company
of an initial business combination and the Company’s liquidation (in each case as described in the Registration Statement
on Form S-1 (File No. 333-248916) filed with the Securities and Exchange Commission) (such earlier date hereinafter referred to
as the “Termination Date”):


 


		1.	FirstMark
                                         shall make available to the Company, at 100 5th Ave, 3rd Floor,
                                         New York, NY 10011 (or any successor location or other existing office locations of FirstMark
                                         or any of its affiliates), certain office space, administrative and support services,
                                         including compliance services, as may be reasonably requested by the Company. In exchange
                                         therefor, the Company shall pay, on the first day of each month, FirstMark the sum of
                                         $10,000 per month commencing on the Listing Date and continuing monthly thereafter until
                                         the Termination Date; and



 


		2.	FirstMark
                                         hereby irrevocably waives any and all right, title, interest, causes of action and claims
                                         of any kind or nature whatsoever (each, a “Claim”) in or to,
                                         and any and all right to seek payment of any amounts due to it out of, the trust account
                                         established for the benefit of the public stockholders of the Company and into which
                                         substantially all of the proceeds of the Company’s initial public offering will
                                         be deposited (the “Trust Account”), and hereby irrevocably
                                         waives any Claim it presently has or may have in the future as a result of, or arising
                                         out of, this letter agreement, which Claim would reduce, encumber or otherwise adversely
                                         affect the Trust Account or any monies or other assets in the Trust Account, and further
                                         agrees not to seek recourse, reimbursement, payment or satisfaction of any Claim against
                                         the Trust Account or any monies or other assets in 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 among 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 all parties hereto.


 


No
party hereto may assign either this letter agreement or any of its rights, interests, or obligations hereunder without the prior
written approval of the other party, provided that FirstMark may assign this letter agreement to an affiliate without the prior
written approval of the Company. Any purported assignment in violation of this paragraph shall be void and ineffectual and shall
not operate to transfer or assign any interest or title to the purported assignee.


 


This
letter agreement, the entire relationship of the parties hereto, and any litigation between the parties (whether grounded in contract,
tort, statute, law or equity) shall be governed by and construed in accordance with the laws of the State of New York.


 


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 letter agreement.


 


[Signature
page follows]


 






     


     


    

 





	 	Very truly yours,
	 	 
	 	FIRSTMARK HORIZON ACQUISITION CORP.
	 	 	 	 
	 	By:	/s/
    Eric Cheung
	 	 	Name: 	Eric
    Cheung
	 	 	Title:	Secretary


 


	AGREED
    TO AND ACCEPTED BY:	 
	 	 
	FirstMark
    Capital LLC	 
	 	 	 	 
	By:	/s/ Richard Heitzmann	 
	 	Name: 	Richard
    Heitzmann	 
	 	Title:	Authorized
    Signatory	 


 


[Signature
Page to Administrative Services Agreement]