Exhibit 4.2


 


NUMBER


 


	 	NUMBER
	 	C 

        SHARES

	 	SEE
    REVERSE FOR
	 	CERTAIN
    DEFINITIONS
	 	CUSIP
    42588L 105


 


HENNESSY
CAPITAL ACQUISITION CORP. III 


INCORPORATED
UNDER THE LAWS OF THE STATE OF DELAWARE


 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 COMMON STOCK OF


 


HENNESSY
CAPITAL ACQUISITION CORP. III


(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 common stock if it is unable to complete a business combination by ___________,
20___ or as more fully described in the Corporation’s final prospectus dated             ,
2017.


 


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.


 


	 	[Corporate
    Seal]	 
	Secretary	Delaware	President


 






     

     


    

 


HENNESSY
CAPITAL ACQUISITION CORP. III


 


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 	 	 	Under
    Uniform Gifts to Minors
	 	 	of
    survivorship and not as tenants in common	 	 
	 	 	 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.


 






    	 	2	 



     


    

 


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             ,
2017, 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 common
stock sold in its initial public offering and liquidates because it does not consummate an initial business combination by __________,
2019, (ii) the Corporation redeems the shares of common stock sold in its initial public offering in connection with a stockholder
vote to approve an amendment to any provision of the Corporation’s amended and restated certificate of incorporation relating
to stockholders’ rights or pre-initial business combination activity, or (iii) if the holder(s) seek(s) to redeem for cash
his, her or its respective shares of 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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