Exhibit 10.2


  


INVESTMENT
MANAGEMENT TRUST AGREEMENT


 


This
Agreement is made as of _________ ___, 2020 by and between Petra Acquisition, Inc. (the “Company”) and Continental
Stock Transfer & Trust Company (“Trustee”).


 


WHEREAS,
the Company’s registration statement on Form S-1, No. 333-240175 (“Registration Statement”) for its initial
public offering of securities (“IPO”) has been declared effective as of the date hereof (“Effective
Date”) by the Securities and Exchange Commission (capitalized terms used herein and not otherwise defined shall have
the meanings set forth in the Registration Statement); and


 


WHEREAS,
LifeSci Capital LLC and Ladenburg Thalmann & Co. Inc. (together the “Representatives” and each a Representative)
is acting as the representative of the several underwriters in the IPO; and


 


WHEREAS,
as described in the Registration Statement, and in accordance with the Company’s Amended and Restated Certificate of Incorporation,
$125,000,000.00 ($143,750,000.00 if the over-allotment option is exercised in full) of the proceeds from the IPO and a simultaneous
private placement of units and warrants 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 Company’s common stock, par value $0.001 per share (“Common Stock”), issued in the IPO as hereinafter
provided (the proceeds to be delivered to the Trustee will be 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;


 


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 at J.P. Morgan Chase Bank, N.A. (or at another U.S. chartered commercial bank with consolidated assets of $100
billion or more) 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 in United States “government
securities” within the meaning of Section 2(a)(16) of the Investment Company Act of 1940, as amended (the “Investment
Company Act”), having a maturity of 185 days or less, and/or in any open ended investment company registered under the
Investment Company Act that holds itself out as a money market fund selected by the Company meeting the conditions of paragraph
(d) of Rule 2a-7 promulgated under the Investment Company Act, which invest only in direct U.S. government treasury obligations;
it being understood that the Trust Account will earn no interest while account funds are uninvested awaiting the Company’s
instructions hereunder and the Trustee may earn bank credits or other consideration during such periods;


 


(d)
Collect and receive, when due, all principal and income arising from the Property, which shall become part of the “Property,”
as such term is used herein;


 


(e)
Notify the Company and the Representatives of all communications received by it with respect to any Property requiring action
by the Company;


 


(f)
Supply any necessary information or documents as may be requested by the Company in connection with the Company’s preparation
of its tax returns;


  






     


     


    

 


(g)
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;


 


(h)
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;


 


(i)
Commence liquidation of the Trust Account only after and promptly after receipt of, and only in accordance with, the terms of
a letter (“Termination Letter”), in a form substantially similar to that attached hereto as either Exhibit
A or Exhibit B, signed on behalf of the Company by its Chief Executive Officer and Chief Financial Officer,
and, in the case of a Termination Letter in a form substantially similar to that attached hereto as Exhibit A, jointly
acknowledged and agreed to by the Representatives, and complete the liquidation of the Trust Account and distribute the Property
in the Trust Account only as directed in the Termination Letter and the other documents referred to therein; provided, however,
that in the event that a Termination Letter has not been received by the Trustee within the period of time (the “Last
Date”) provided in the Company’s Amended and Restated Certificate of Incorporation, as the same may be amended
from time to time (the “Certificate of Incorporation”), the Trust Account shall be liquidated in accordance
with the procedures set forth in the Termination Letter attached as Exhibit B hereto and distributed to the Public
Stockholders as of the Last Date. The provisions of this Section 1(i) may not be modified, amended or deleted
under any circumstances; and


 


(j)
Upon receipt of a letter (an “Amendment Notification Letter”) in the form of Exhibit C, signed
on behalf of the Company by an authorized officer, distribute to Public Stockholders who exercised their conversion rights in
connection with an amendment to Article Sixth of the Company’s Certificate of Incorporation (an “Amendment”)
an amount equal to the pro rata share of the Property relating to the Common Stock for which such Public Stockholders have exercised
conversion rights in connection with such Amendment. The provisions of this Section 1(j) may not be modified,
amended or deleted under any circumstances.


 


2. Limited
Distributions of Income from Trust Account.


 


(a)
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 to the Company the amount of interest income earned on the Trust Account
requested by the Company to cover any income or other tax obligation owed by the Company.


 


(b)
[Intentionally Omitted]


 


(c)
The limited distributions referred to in Sections 2(a) above shall be made only from income collected on the Property.
Except as provided in Sections 2(a)  above, no other distributions from the Trust Account shall be permitted
except in accordance with Sections 1(i) or 1(j) hereof.


 


(d)
The Company shall provide the Representatives with a copy of any Termination Letter, Amendment Notification Letter, and/or any
other correspondence that it issues to the Trustee with respect to any proposed withdrawal from the Trust Account promptly after
such issuance.


 


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


 


(a)
Give all instructions to the Trustee hereunder in writing, signed by any one of the Company’s authorized officers. In addition,
except with respect to its duties under Sections 1(i), 1(j),and 2(a)  above, 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 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;


 






    2


     


    

 


(b)
Subject to the provisions of Section 5 of this Agreement, 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 claim, potential claim, action, suit, or other proceeding brought against the Trustee which in any way
arises out of or relates to this Agreement, the services of the Trustee hereunder, or the Property or any income earned from investment
of the Property, except for expenses and losses resulting from the Trustee’s gross negligence 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 paragraph, 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 consent shall not be unreasonably withheld. The Company may participate
in such action with its own counsel;


 


(c)
Pay the Trustee an initial acceptance fee, an annual fee, and a transaction processing fee for each disbursement made pursuant
to Section 2(a) as set forth on Schedule A hereto, 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 and further
agreed that any fees owed to the Trustee shall be deducted by the Trustee from the disbursements made to the Company pursuant
to Section 1(i) solely in connection with the consummation of a business combination (a “Business Combination”).
The Company shall pay the Trustee the initial acceptance fee and first year’s fee at the consummation of the IPO and thereafter
on the anniversary of the Effective Date;


 


(d)
In connection with any vote of the Company’s stockholders regarding a Business Combination, provide to the Trustee an affidavit
or certificate of a firm regularly engaged in the business of soliciting proxies and/or tabulating stockholder votes verifying
the vote of the Company’s stockholders regarding such Business Combination;


 


(e)
In the event that the Company directs the Trustee to commence liquidation of the Trust Account pursuant to Section 1(i),
the Company agrees that it will not direct the Trustee to make any payments that are not specifically authorized by this Agreement;
and


 


(f)
If the Company has an Amendment approved by its stockholders, provide the Trustee with an Amendment Notification Letter in the
form of Exhibit C providing instructions for the distribution of funds to Public Stockholders who exercise their
conversion rights in connection with such Amendment.


 


4. Limitations
of Liability. The Trustee shall have no responsibility or liability to:


 


(a)
Take any action with respect to the Property, other than as directed in Sections 1 and 2 hereof,
and the Trustee shall have no liability to any party except for liability arising out of its own gross negligence or willful misconduct;


 


(b)
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;


 


(c)
Change the investment of any Property, other than in compliance with Section 1(c);


 


(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 exercise of its own best judgment, except for its gross negligence 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), 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 Trustee, in good faith, 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;


 






    3


     


    

 


(g)
Verify the correctness of the information set forth in the Registration Statement or to confirm or assure that any Business Combination
consummated by the Company or any other action taken by it is as contemplated by the Registration Statement;


 


(h)
File local, state, and/or federal tax returns or information returns with any taxing authority on behalf of the Trust Account
or deliver payee statements to the Company documenting the taxes, if any, payable by the Company or the Trust Account, relating
to the income earned on the Property;


 


(i)
Pay any taxes on behalf of the Trust Account (it being expressly understood that the Property shall not be used to pay any such
taxes and that such taxes, if any, shall be paid by the Company from funds not held in the Trust Account or released to it under Section
2(a) hereof);


 


(j)
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; or


 


(k)
Verify calculations, qualify, or otherwise approve Company requests for distributions pursuant to Sections 1(i), 1(j),
or  2(a) above.


 


5. 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 Section 3(b) or Section 3(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.


 


6. 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 during which time the Trustee shall act in accordance with this Agreement. At such time
that the Company notifies the Trustee that a successor trustee has been appointed by the Company 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


 


(b)
At such time that the Trustee has completed the liquidation of the Trust Account in accordance with the provisions of Section
1(i) hereof, and distributed the Property in accordance with the provisions of the Termination Letter, this Agreement shall
terminate except with respect to Section 3(b) and Section 5.


 


7. Miscellaneous.


 


(a)
The Company and the Trustee will each restrict access to confidential information relating to funds being transferred to or from
the Trust Account 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 information, or of any change in its authorized personnel. In executing funds transfers,
the Trustee will 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. The Trustee shall not be liable
for any loss, liability, or expense resulting from any error in the information supplied to it or funds transferred based on such
information.


  






    4


     


    

 


(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. 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.


 


(c)
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.


 


(d)
This Agreement contains the entire agreement and understanding of the parties hereto with respect to the subject matter hereof.
Except for Sections 1(i) and 1(j) (which may not be amended under any circumstances), this Agreement
or any provision hereof may only be changed, amended, or modified by a writing signed by each of the parties hereto; provided,
however, that no such change, amendment or modification may be made without the prior written consent of the Representatives.
The Trustee may require from Company counsel an opinion as to the propriety of any proposed amendment.


 


(e)
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 Trustee, to:


 


Continental
Stock Transfer & Trust Company


1
State Street, 30th floor


New
York, New York 10004


Attn:
Francis Wolf and Celeste Gonzalez


Email:
fwolf@continentalstock.com


Email:
cgonzalez@continentalstock.com


 


if
to the Company, to:


 


Petra
Acquisition, Inc.


5
West 21st Street


New
York, NY 10010


Attn:
Andreas Typaldos, CEO


E-mail:
atypaldos@gmail.com


 


in
either case with a copy (which copy shall not constitute notice) to:


 


LifeSci
Capital LLC


250
West 55th Street, Suite 3401


New
York, NY 10019


Attn:
David Dobkin, Managing Director


E-mail:
ddobkin@lifescicapital.com


 


and


Ladenburg
Thalmann & Co. Inc.


277
Park Avenue, 26th Floor


New
York, NY 10172


Attn:
Steven Kaplan, Head of Capital Markets


Email:
Skaplan@ladenburg.com


 






    5


     


    

 


and


Horwitz
+ Armstrong, APLC


14
Orchard, Suite 200


Lake
Forest, CA 92630


Attn:
Lawrence W. Horwitz, Esq.


Jessica
M. Lockett, Esq.


E-mail:
lhorwitz@horwitzarmstrong.com


jlockett@horwitzarmstrong.com


 


and


Ellenoff
Grossman & Schole LLP


1345
Avenue of the Americas


New
York, New York 10105


Attn:
Stuart Nuehauser, Esq.


Email:
sneuhauser@egsllp.com


 


(f)
This Agreement may not be assigned by the Trustee without the prior consent of the Company.


 


(g)
Each of the Trustee and the Company 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.


 


(h)
Each of the Company and the Trustee hereby acknowledge that the Representatives are a third party beneficiary of this Agreement.


  


[Signature
Page Follows]


 






    6


     


    

 


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:	 
	 	 	Name:	 
    Francis Wolf
	 	 	Title:	 
    Vice President
	 	 	 	 
	 	PETRA
    ACQUISITION, INC.
	 	 	 	 
	 	By:	 
	 	 	Name:	 Andreas
    Typaldos
	 	 	Title:	 Chief
    Executive Officer


 






     


     


    

 


SCHEDULE
A


 


	Fee
    Item	 	Time
    and method of payment	 	Amount	 
	Initial
    acceptance fee	 	Initial
    closing of IPO by wire transfer	 	$	3,500.00	 
	Annual
    fee	 	First
    year, initial closing of IPO by wire transfer; thereafter on the anniversary of the effective date of the IPO by wire transfer
    or check	 	$	10,000.00	 
	Transaction
    processing fee for disbursements to Company under Section 2	 	Billed
    to the Company following disbursement made to Company under Section 2	 	$	250.00	 
	Paying
    Agent services as required pursuant to section 1(i) and 1(j)	 	Billed
    to Company upon delivery of service pursuant to section 1(i) and 1(j)	 	 	 Prevailing
    rates	 


 


Sch
A-1


 






     


     


    

 


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 Petra Acquisition, Inc. (“Company”) and
Continental Stock Transfer & Trust Company, dated as of ______ ___, 2020 (“Trust Agreement”), this is to
advise you that the Company has entered into an agreement with [__________________] to consummate a business combination (“Business
Combination”) on or about [insert date]. The Company shall notify you at least 72 hours in advance of the
actual date of the consummation of the Business Combination (“Consummation Date”). Capitalized terms used herein
and not otherwise defined 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 the Trust Account investments and to transfer
the proceeds to the Trust Account at J.P. Morgan Chase Bank, N.A. to the effect that, on the Consummation Date, all of funds held
in the Trust Account 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 account 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 and (ii) the Company shall deliver to you (a) a certificate of the Chief Executive Officer, which verifies the
vote of the Company’s stockholders in connection with the Business Combination if a vote is held and (b) joint written instructions
from the Company and the Representatives with respect to the transfer of the funds held in the Trust Account (“Instruction
Letter”). You are hereby directed and authorized to transfer the funds held in the Trust Account immediately upon your
receipt of the counsel's letter 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 of the same and the Company shall direct you as to whether such funds should remain in the Trust Account and distributed
after the Consummation Date to the Company. Upon the distribution of all the funds in the Trust Account pursuant to the terms
hereof, 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 you of written
instructions from the Company, the funds held in the Trust Account shall be reinvested as provided in the Trust Agreement on the
business day immediately following the Consummation Date as set forth in the notice.


 


	 	Very
    truly yours,
	 	 
	 	PETRA
    ACQUISITION, INC.
	 	 	 
	 	By:	 
	 	 	Name:
	 	 	Title:
    Chief Executive Officer
	 	 	 	 
	 	By:	 
	 	 	Name:
    
	 	 	Title:
    Chief Financial Officer


  


AGREED
TO AND ACKNOWLEDGED BY:


 


	LIFESCI
    CAPITAL LLC	 
	 	 	 	 
	By:	 	 
	 	Name: 	 	 
	 	Title:	 	 


  


	LADENBURG
    THALMANN & CO. INC.	 
	 	 	 	 
	By:	 	 
	 	Name: 	 	 
	 	Title:	 	 


 






     


     


    

 


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 Petra Acquisition, Inc. (“Company”) and
Continental Stock Transfer & Trust Company, dated as of ________ ___, 2020 (“Trust Agreement”), this is
to advise you that the Company has been unable to effect a Business Combination with a Target Company within the time frame specified
in the Company’s Amended and Restated Certificate of Incorporation, as described in the Company’s prospectus relating
to its IPO. Capitalized terms used herein and not otherwise defined 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 the Trust Account and to transfer the total
proceeds of the Trust to the Trust Account at J.P. Morgan Chase Bank, N.A. to await distribution to the Public Stockholders. The
Company has selected [____________, 20__] as the date for when the Public Stockholders will be entitled to receive their share
of the liquidation proceeds. It is acknowledged that while the funds are on deposit in the Trust Account awaiting distribution,
the Company will not earn any interest or dividends. You agree to be the Paying Agent of record and in your separate capacity
as Paying Agent, to distribute said funds directly to the 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 in the Trust
Account, your obligations under the Trust Agreement shall be terminated.


 


	 	Very
    truly yours,
	 	 
	 	PETRA
    ACQUISITION, INC.
	 	 	 	 
	 	By:	 
	 	 	Name:	 
	 	 	Title:
    Chief Executive Officer
	 	 	 	 
	 	By:	 
	 	 	Name:	 
	 	 	Title:
    Chief Financial Officer


 


		cc:	LifeSci
Capital LLC



Ladenburg
Thalmann & Co. Inc.


  






     


     


    

 


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 – Amendment Notification Letter


 


Dear
Mr. Wolf and Ms. Gonzalez:


 


Reference
is made to the Investment Management Trust Agreement between Petra Acquisition, Inc. (“Company”) and Continental
Stock Transfer & Trust Company, dated as of ________ ___, 2020 (“Trust Agreement”). Capitalized words used
herein and not otherwise defined shall have the meanings ascribed to them in the Trust Agreement.


 


Pursuant
to Section 1(j) of the Trust Agreement, this is to advise you that the Company has sought an Amendment. Accordingly, in accordance
with the terms of the Trust Agreement, we hereby authorize you to liquidate a sufficient portion of the Trust Account and to transfer
$____ of the total proceeds of the Trust to the Trust Account at J.P. Morgan Chase Bank, N.A. to await distribution to the Public
Stockholders that have requested conversion of their shares in connection with such Amendment. The remaining funds shall be reinvested
by you as previously instructed.


 


	 	Very
    truly yours,
	 	 
	 	PETRA
    ACQUISITION, INC.
	 	 	 	 
	 	By:	 
	 	 	Name:    
	 	 	Title:
    Chief Executive Officer
	 	 	 	 
	 	By:	 
	 	 	Name:
	 	 	Title:
    Chief Financial Officer


  


		cc:	LifeSci
Capital LLC



Ladenburg
Thalmann & Co. Inc.


  






     


     


    

 


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 – Tax Reimbursement Withdrawal Letter


 


Dear
Mr. Wolf and Ms. Gonzalez:


 


[Pursuant
to Section 2(a) of the Investment Management Trust Agreement between Petra Acquisition, Inc. (“Company”) and
Continental Stock Transfer & Trust Company, dated as of _______ ___, 20__ (“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.
The Company needs such funds to pay for its tax obligations as a result of such interest income.]


 


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]


 


	 	PETRA
    ACQUISITION, INC.
	 	 	 	 
	 	By:	 
	 	 	Name:	 
	 	 	Title:	 
	 	 	 	 


  


		cc:	LifeSci
Capital LLC



Ladenburg
Thalmann & Co. Inc.