Exhibit 10.6


 


STOCK ESCROW AGREEMENT


 


STOCK ESCROW AGREEMENT,
dated as of [_____], 2020 (“Agreement”), by and among PETRA ACQUISITION, INC., a Delaware corporation (“Company”),
the stockholder of the Company listed on Exhibit A hereto (the “Founder”) and CONTINENTAL STOCK TRANSFER &
TRUST COMPANY, a New York corporation (“Escrow Agent”).


 


WHEREAS, the Company was
formed for the purpose of completing a merger, stock exchange, asset acquisition, stock purchase, recapitalization, reorganization
or other similar business combination (a “Business Combination”) with one or more businesses or entities.


 


WHEREAS, the Company has
entered into an Underwriting Agreement, dated [_____], 2020 (“Underwriting Agreement”), with LifeSCI
CAPITAL LLC and Ladenburg thalmann & Co. inc.  (together the “Representatives”,
each a “Representative”) acting as representative of the several underwriters (collectively, the “Underwriters”),
pursuant to which, among other matters, the Underwriters have agreed to purchase 12,500,000 units (“Units”) of the
Company, plus an additional 1,875,000 Units if the Representatives exercise the over-allotment option in full. Each Unit consists
of one share of the Company’s common stock, par value $0.001 per share (“Common Stock”), and one-half of one
warrant (“Warrant”), each whole Warrant to purchase one share of Common Stock, all as more fully described in the Company’s
final Prospectus, dated [_____], 2020 (“Prospectus”) comprising part of the Company’s Registration Statement
on Form S-1 (File No. 333-240175) under the Securities Act of 1933, as amended (“Registration Statement”), declared
effective on [_____], 2020 (“Effective Date”).


 


WHEREAS, the Founder has
agreed as a condition of the sale of the Units to deposit its shares of Common Stock of the Company in escrow as hereinafter provided.


 


WHEREAS, the Company and
the Founder desire that the Escrow Agent accept the shares of Common Stock, in escrow, to be held and disbursed as hereinafter
provided.


 


IT IS AGREED:


 


1. Appointment
of Escrow Agent. The Company and the Founder hereby appoint the Escrow Agent to act in accordance with and subject to the terms
of this Agreement and the Escrow Agent hereby accepts such appointment and agrees to act in accordance with and subject to such
terms.


 


2. Deposit of Shares.
On or before the Effective Date, the Founder shall have delivered to the Escrow Agent certificates (and applicable stock powers
if requested by the Escrow Agent) representing such Founder’s respective shares of Common Stock set forth on Exhibit A
hereto, to be held and disbursed subject to the terms and conditions of this Agreement. The Founder acknowledges that the certificate
representing such Founder’s shares is legended to reflect the deposit of such shares under this Agreement.


 


3. Disbursement
of the Escrow Shares.


 


3.1 If the over-allotment
option to purchase all or a portion of the additional 1,875,000 Units of the Company is not exercised in full within 45 days of
the date of the Prospectus (as described in the Underwriting Agreement), the Founder agrees that the Escrow Agent shall return
to the Company for cancellation, at no cost, the number of shares of Common Stock held by it determined by multiplying 468,750
multiplied by a fraction, (i) the numerator of which is 1,875,000 minus the number of shares of Common Stock included in the Units
purchased by the Underwriters upon the exercise of the over-allotment option, and (ii) the denominator of which is 1,875,000. The
Company shall promptly provide notice to the Escrow Agent of the expiration or termination of the over-allotment option and the
number of Units, if any, purchased by the Underwriters in connection with the exercise thereof


 






    


     


    

3.2 Except as otherwise set
forth herein, the Escrow Agent shall hold the shares remaining after any cancellation required pursuant to Section 3.1, if any,
above (such remaining shares to be referred to herein as the “Escrow Shares”) until (i) with respect to 50% of the
Escrow Shares, the earlier of (x) three months after the date of the consummation of an initial Business Combination and (y) the
date on which the last sale price of the Common Stock equals or exceeds $12.50 per share (as adjusted for stock splits, stock dividends,
reorganizations and recapitalizations) for any 20 trading days within any 30-trading day period following the consummation of the
Business Combination and (ii) with respect to the remaining 50% of the Escrow Shares, six months after the date of the consummation
of an initial Business Combination (such period of time during which the Escrow Shares are held in escrow, the “Escrow Period”).
The Company shall promptly provide notice of the consummation of an initial Business Combination to the Escrow Agent. Upon completion
of the Escrow Period, the Escrow Agent shall disburse such amount of each Founder’s Escrow Shares to such Founder; provided,
however, that if, within the Escrow Period, the Company (or the surviving entity) subsequently consummates a liquidation, merger,
stock exchange or other similar transaction which results in all of the stockholders of such entity having the right to exchange
their shares of Common Stock for cash, securities or other property, then the Escrow Agent will, upon receipt of a notice executed
by the Chairman of the Board, Chief Executive Officer or other authorized officer of the Company, in form reasonably acceptable
to the Escrow Agent, certifying that such transaction is then being consummated or such conditions have been achieved, as applicable,
release the Escrow Shares to the Founder. The Escrow Agent shall have no further duties hereunder after the disbursement of the
Escrow Shares in accordance with this Section 3.2.


 


3.3 If the Escrow Agent
is notified by the Company pursuant to Section 6.7 hereof that the Company is being liquidated, then the Escrow Agent shall deliver
the certificates representing the Escrow Shares to the Founder promptly after the public stockholders are paid the liquidating
distributions and shall have no further duties hereunder.


 


4. Rights of Founder
in Escrow Shares.


 


4.1 Voting Rights
as a Stockholder. Subject to the terms of the Insider Letters described in Section 4.4 hereof and except as herein provided,
the Founder shall retain all of their rights as stockholders of the Company as long as any shares are held in escrow pursuant to
this Agreement, including, without limitation, the right to vote such shares.


 


4.2 Dividends and
Other Distributions in Respect of the Escrow Shares. For as long as any shares are held in escrow pursuant to this Agreement,
all dividends payable in cash with respect to the Escrow Shares shall be paid to the Founder, but all dividends payable in stock
or other non-cash property (“Non-Cash Dividends”) shall be delivered to the Escrow Agent to hold in accordance with
the terms hereof. As used herein, the term “Escrow Shares” shall be deemed to include the Non-Cash Dividends distributed
thereon, if any.


 


4.3 Restrictions
on Transfer. During the Escrow Period, the only permitted transfers of the Escrow Shares will be (i) to the Founder and the
Company’s officers, directors, employees, consultants or their affiliates, (ii) to a Founder’s stockholders, partners
or members upon the Founder’s liquidation, (iii) by bona fide gift to a member of the Founder’s immediate family or
to a trust, the beneficiary of which is the Founder or a member of the Founder’s immediate family for estate planning purposes,
(iv) by virtue of the laws of descent and distribution upon death of the Founder, (v) pursuant to a qualified domestic relations
order binding on the Founder, (vi) to the Company for no value for cancellation in connection with the consummation of a Business
Combination or (vii) by private sales of the Escrow Shares made at or prior to the consummation of a Business Combination at prices
no greater than the price at which the Escrow Shares were originally purchased; provided, however, that except for clause (vi)
or with the Company’s prior written consent, such permitted transfers may be implemented only upon the respective transferee’s
written agreement to be bound by the terms and conditions of this Agreement and of the Insider Letter signed by the Founder transferring
the shares.


 


4.4 Insider Letters.
The Founder has executed a letter agreement with the Company and the Representatives, dated as of the date hereto, the form of
which is filed as an exhibit to the Registration Statement (“Insider Letter”), respecting the rights and obligations
of such Founder in certain events, including, but not limited to, the liquidation of the Company.


  






    


     


    

5. Concerning the
Escrow Agent.


 


5.1 Good Faith Reliance.
The Escrow Agent shall not be liable for any action taken or omitted by it in good faith and in the exercise of its own best judgment,
and 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 Escrow Agent), 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 is believed by the Escrow Agent in good faith to be genuine and to be signed or presented by the proper person
or persons. The Escrow Agent shall not be bound by any notice or demand, or any waiver, modification, termination or rescission
of this Agreement unless evidenced by a writing delivered to the Escrow Agent signed by the proper party or parties and, if the
duties or rights of the Escrow Agent are affected, unless it shall have given its prior written consent thereto.


 


5.2 Indemnification.
Subject to Section 5.8 below, the Escrow Agent shall be indemnified and held harmless by the Company from and against any expenses,
including reasonable counsel fees and disbursements, or loss suffered by the Escrow Agent in connection with any action, suit or
other proceeding involving any claim which in any way, directly or indirectly, arises out of or relates to this Agreement, the
services of the Escrow Agent hereunder, or the Escrow Shares held by it hereunder, other than expenses or losses arising from the
gross negligence, fraud or willful misconduct of the Escrow Agent. Promptly after the receipt by the Escrow Agent of notice of
any demand or claim or the commencement of any action, suit or proceeding, the Escrow Agent shall notify the other parties hereto
in writing. In the event of the receipt of such notice, the Escrow Agent, in its sole discretion, may commence an action in the
nature of interpleader in an appropriate court to determine ownership or disposition of the Escrow Shares or it may deposit the
Escrow Shares with the clerk of any appropriate court or it may retain the Escrow Shares pending receipt of a final, non-appealable
order of a court having jurisdiction over all of the parties hereto directing to whom and under what circumstances the Escrow Shares
are to be disbursed and delivered. The provisions of this Section 5.2 shall survive in the event the Escrow Agent resigns or is
discharged pursuant to Sections 5.5 or 5.6 below.


 


5.3 Compensation.
Subject to Section 5.8 below, the Escrow Agent shall be entitled to reasonable compensation from the Company for all services rendered
by it hereunder. The Escrow Agent shall also be entitled to reimbursement from the Company for all reasonable expenses paid or
incurred by it in the administration of its duties hereunder including, but not limited to, all counsel, advisors’ and agents’
fees and disbursements and all taxes or other governmental charges.


 


5.4 Further Assurances.
From time to time on and after the date hereof, the Company and the Founder shall deliver or cause to be delivered to the Escrow
Agent such further documents and instruments and shall do or cause to be done such further acts as the Escrow Agent shall reasonably
request to carry out more effectively the provisions and purposes of this Agreement, to evidence compliance herewith or to assure
itself that it is protected in acting hereunder.


 


5.5 Resignation.
The Escrow Agent may resign at any time and be discharged from its duties as escrow agent hereunder by its giving the other parties
hereto written notice and such resignation shall become effective as hereinafter provided. Such resignation shall become effective
at such time that the Escrow Agent shall turn the Escrow Shares over to a successor escrow agent appointed by the Company and approved
by the Representatives, which approval will not be unreasonably withheld, conditioned or delayed. If no new escrow agent is so
appointed within the 60-day period following the giving of such notice of resignation, the Escrow Agent may deposit the Escrow
Shares with any court it reasonably deems appropriate in the State of New York.


 


5.6 Discharge of
Escrow Agent. The Escrow Agent shall resign and be discharged from its duties as escrow agent hereunder if so requested in
writing at any time by all of the other parties hereto; provided, however, that such resignation shall become effective only upon
the appointment of a successor escrow agent selected by the Company and approved by the Representatives, which approval will not
be unreasonably withheld, conditioned or delayed.


 






    


     


    

5.7 Liability.
Notwithstanding anything herein to the contrary, the Escrow Agent shall not be relieved from liability hereunder for its own gross
negligence, fraud or willful misconduct.


 


5.8 Waiver. The
Escrow Agent hereby waives any right of set-off or any other right, title, interest or claim of any kind (“Claim”)
in, or to any distribution of, the Trust Account (as defined in that certain Investment Management Trust Agreement, dated as of
the date hereof, by and between the Company and the Escrow Agent as trustee thereunder) and hereby agrees not to seek recourse,
reimbursement, payment or satisfaction for any Claim against the Trust Account for any reason whatsoever.


  


6. Miscellaneous.


 


6.1 Governing Law.
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. The
parties hereto consent to the jurisdiction and venue of any state or federal court located in the City of New York, Borough of
Manhattan, 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.


 


6.2 Third Party Beneficiaries.
Each of the parties to this Agreement hereby acknowledges that the Representatives are each a third party beneficiary of this Agreement.


 


6.3 Entire Agreement.
This Agreement contains the entire agreement of the parties hereto with respect to the subject matter hereof and, except as expressly
provided herein, may only be changed, amended, or modified by a writing signed by each of the parties hereto.


 


6.4 Headings.
The headings contained in this Agreement are for reference purposes only and shall not affect in any way the meaning or interpretation
thereof.


 


6.5 Binding Effect.
This Agreement shall be binding upon and inure to the benefit of the respective parties hereto and their legal representatives,
successors and assigns.


 


6.6 Notices.
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,
by email or by facsimile transmission:


 


If to the Company, to:


 


Petra Acquisition, Inc.


5 West 21st Street


New York, NY 1001


Attn: Andreas Typaldos


Fax No.:


Email:atypaldos@gmail.com


 


If to a Founder, to his/her/its
address set forth in Exhibit A.


 


and if to the Escrow Agent,
to:


 


Continental Stock Transfer&
Trust Company


1 State Street


New York, New York 10004


Attn: Chairman


Fax No.:


Email:


 


A copy of any notice sent
hereunder shall be sent to:


 


LifeSci Capital
LLC


250 West 55th
Street, Suite 3401


New York, NY 10019


Attn: David Dobkin


Fax No.:


Email: ddobkin@lifescicapital.com


 






    


     


    

and


Ladenburg Thalmann & Co. Inc.


277 Park Avenue, 26th Floor


New York, NY 10172


Attn: Steven Kaplan, Head of Capital
Markets


Fax No.:


Email: Skaplan@ladenburg.com


 


with a copy to:


 


Horwitz + Armstrong, APLC


14 Orchard, Suite 200


Lake Forest, CA 92630


Attn: Lawrence W. Horwitz, Esq.


Fax No.: (949) 540-6578


Email: lhorwitz@horwitzarmstrong.com


 


and:


 


Ellenoff Grossman&
Schole LLP


1345 Avenue of
the Americas


New York, New York
10105


Attn: Stuart Nuehauser,
Esq.


Fax No.: (212)
370-7889


Email: sneuhauser@egsllp.com


 


The parties may change the
persons and addresses to which the notices or other communications are to be sent by giving written notice to any such change in
the manner provided herein for giving notice.


 


6.7 Liquidation of
the Company. The Company shall give the Escrow Agent written notification of the liquidation and dissolution of the Company
in the event that the Company fails to consummate a Business Combination within the time period specified in the Company’s
Amended and Restated Certificate of Incorporation, as the same may be amended from time to time.


 


6.8 Counterparts.
This Agreement may be executed in several counterparts, each one of which shall constitute an original and may be delivered by
facsimile transmission and together shall constitute one instrument.


 


[Signature Page Follows]


 


 



    


     


    




WITNESS the execution of
this Agreement as of the date first above written.


 


 


	 	
        COMPANY:

        

        PETRA ACQUISITION, INC.

	 	 
	 	By:	 
	 	Name:	Andreas Typaldos
	 	Title:	Chief Executive Officer
	 	 
	 	FOUNDERS:
	 	 
	 	PETRA INVESTMENT HOLDINGS, LLC
	 	 
	 	By:	 
	 	Name:	Andreas Typaldos
	 	Title:	Managing Member
	 	 
	 	 DAVID DOBKIN
	 	 
	 	 	 
	 	 	Signature 
	 	
         

        ANTHONY HAYES

	 	 
	 	 	 
	 	 	Signature 
	 	
         

        ROBERT NICHOLSON

	 	 
	 	 	 
	 	 	Signature 
	 	 	 
	 	
         

        BARRY DENNIS

	 	 
	 	 	 
	 	:	 Signature
	 	 	 


 


	 	
         

        ESCROW AGENT:

         

        CONTINENTAL STOCK TRANSFER & TRUST COMPANY

	 	 
	 	By:	 
	 	Name:	 
	 	Title:	 


 


 



    


     


    




EXHIBIT A


 


	Name and Address of Founder	 	Number of Shares	 
	
        Petra Investment Holdings, LLC

        5 West 21st Street,

        New York, NY 10010
	 	 	3,493,750	 
	Anthony Hayes	 	 	   25,000 	 
	David Dobkin	 	 	25,000	 
	Robert Nicholson	 	 	25,000 	 
	Barry Dennis	 	 	25,000