Exhibit 4.2


 


	NUMBER	NUMBER
	 	C-
	 	SHARES
	 	SEE REVERSE FOR CERTAIN DEFINITIONS
	 	CUSIP 629076 100


 


NEBULA ACQUISITION
CORPORATION


 


INCORPORATED
UNDER THE LAWS OF THE STATE OF DELAWARE 

CLASS A COMMON STOCK


 


This Certifies that


 


is the owner of


 


FULLY PAID AND NON-ASSESSABLE SHARES
OF THE PAR VALUE OF $0.0001 EACH OF THE CLASS A COMMON STOCK OF


 


NEBULA ACQUISITION
CORPORATION

(THE “CORPORATION”)


 


transferable on the books of the Corporation
in person or by duly authorized attorney upon surrender of this certificate properly endorsed.


 


The Corporation will be forced to redeem
all of its shares of Class A common stock if it is unable to complete a business combination by                      ,
2020, all as more fully described in the Corporation’s final prospectus dated                        ,
2018.


 


This certificate is not valid unless
countersigned by the Transfer Agent and registered by the Registrar.


 


Witness the seal of the Corporation
and the facsimile signatures of its duly authorized officers.


 


	Co-Chief Executive Officer	[Corporate Seal] Delaware	Co-Chief Executive Officer
	 	 	 


 


NEBULA ACQUISITION
CORPORATION


 


The Corporation will furnish without
charge to each stockholder who so requests the powers, designations, preferences and relative, participating, optional or other
special rights of each class of stock or series thereof of the Corporation and the qualifications, limitations, or restrictions
of such preferences and/or rights. This certificate and the shares represented thereby are issued and shall be held subject to
all the provisions of the Certificate of Incorporation and all amendments thereto and resolutions of the Board of Directors providing
for the issue of securities (copies of which may be obtained from the secretary of the Corporation), to all of which the holder
of this certificate by acceptance hereof assents. The following abbreviations, when used in the inscription on the face of this
certificate, shall be construed as though they were written out in full according to applicable laws or regulations:


 


	TEN COM	—	as tenants in common	UNIF GIFT MIN ACT	—	 	Custodian	 
	TEN ENT	—	as tenants by the entireties	 	 	(Cust)	 	(Minor)





	JT TEN	—	as joint tenants with right of survivorship and not as tenants in common	 	 	
        under Uniform Gifts to Minors Act

         

        (State)



 






     


    


    

 


Additional abbreviations may also be
used though not in the above list.


 


For value received,                   
hereby sells, assigns and transfers unto


 


(PLEASE INSERT
SOCIAL SECURITY OR OTHER IDENTIFYING NUMBER(S) OF ASSIGNEE(S))


 


(PLEASE PRINT OR
TYPEWRITE NAME(S) AND ADDRESS(ES), INCLUDING ZIP CODE, OF ASSIGNEE(S))


 


Shares of the capital stock represented
by the within Certificate, and hereby irrevocably constitutes and appoints


 


Attorney to transfer the said stock
on the books of the within named Corporation with full power of substitution in the premises.


 


	Dated:	 
	 


 


	 


NOTICE: THE SIGNATURE(S) TO THIS
ASSIGNMENT MUST CORRESPOND WITH THE NAME AS WRITTEN UPON THE FACE OF THE CERTIFICATE IN EVERY PARTICULAR, WITHOUT ALTERATION OR
ENLARGEMENT OR ANY CHANGE WHATEVER.


 


	Signature(s) Guaranteed:	 
	By	 
	 	 


 


	 


THE SIGNATURE(S) MUST BE GUARANTEED
BY AN ELIGIBLE GUARANTOR INSTITUTION (BANKS, STOCKBROKERS, SAVINGS AND LOAN ASSOCIATIONS AND CREDIT UNIONS WITH MEMBERSHIP IN AN
APPROVED SIGNATURE GUARANTEE MEDALLION PROGRAM, PURSUANT TO S.E.C. RULE 17Ad-15 (OR ANY SUCCESSOR RULE).


 


In each case, as more fully described
in the Corporation’s final prospectus dated                   ,
2018, the holder(s) of this certificate shall be entitled to receive a pro-rata portion of certain funds held in the trust
account established in connection with its initial public offering only in the event that (i) the Corporation redeems the
shares of Class A common stock sold in the Company’s initial public offering and liquidates because it does not consummate
an initial business combination by                   ,
2020, (ii) the Corporation redeems the shares of Class A common stock sold in its initial public offering in connection
with a stockholder vote to amend the Corporation’s amended and restated certificate of incorporation to modify the substance
or timing of the Corporation’s obligation to redeem 100% of the Class A common stock if it does not consummate an initial
business combination by                   ,
2020, or (iii) if the holder(s) seek(s) to redeem for cash his, her or its respective shares of Class A common
stock in connection with a tender offer (or proxy solicitation, solely in the event the Corporation seeks stockholder approval
of the proposed initial business combination) setting forth the details of a proposed initial business combination. In no other
circumstances shall the holder(s) have any right or interest of any kind in or to the trust account.


 


 


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