Exhibit 4.2


 


	NUMBER C- 	 	
        _________ SHARES

        SEE REVERSE FOR CERTAIN DEFINITIONS

        CUSIP G85094 103



 


STONEBRIDGE ACQUISITION CORPORATION

INCORPORATED UNDER THE LAWS OF THE CAYMAN ISLANDS

CLASS A ORDINARY SHARES


 


This Certifies that [●] is the owner
of 


 


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


 


STONEBRIDGE ACQUISITION CORPORATION


(THE “COMPANY”)


 


subject to the Company’s amended and restated memorandum
and articles of association, as the same may be amended from time to time, and transferable on the books of the Company in person
or by duly authorized attorney upon surrender of this certificate properly endorsed.


 


The Company will be forced to redeem all of its Class A ordinary
shares if it is unable to complete a business combination by , 2023 all as more fully described in the Company’s final prospectus
dated , 2021.


 


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


 


Witness the facsimile signatures of its duly authorized officers.


 


	Chief Executive Officer	Cayman Islands	Secretary
	 	 	 


 


	CONTINENTAL STOCK TRANSFER

    & TRUST COMPANY	 	 
	 	 	 
	Name:	 	 
	Title:	 	 


STONEBRIDGE ACQUISITION CORPORATION


 


The Company will furnish without charge to each shareholder
who so requests the powers, designations, preferences and relative, participating, optional or other special rights of each class
of shares or series thereof of the Company 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 amended and
restated memorandum and articles of association as the same may be amended from time to time, and resolutions of the Board of Directors
providing for the issue of securities (copies of which may be obtained from the secretary of the Company), 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	 	 
	 	 	 	 	 	 	 	 	 	 	(Cust)	 	 	 	(Minor)
	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 


	TEN ENT	 	—	 	as tenants by the entireties	 	 	 	 	 	 	 	 	 	 
	 	 	 	 	 	 	 	 	 	 	Under Uniform Gifts to Minors 
	 	 	 	 	 	 	 	 	 	 	 
	JT TEN	 	—	 	as joint tenants with right 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 represented by the within Certificate, and hereby irrevocably constitutes and appoints___________________
	 
	Attorney to transfer the said shares on the books of the within named Company 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) UNDER THE SECURITIES ACT OF 1933, AS AMENDED).


 


In each case, as more fully described in the Company’s
final prospectus dated , 2021, 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 Company redeems
the Class A ordinary shares sold in its initial public offering and liquidates because it does not consummate an initial business
combination by , 2023, (ii) the Company redeems the Class A ordinary shares sold in its initial public offering in connection with
a shareholder vote to amend the Company’s amended and restated memorandum and articles of association (as the same may be
amended from time to time) to modify the substance and timing of the Company’s obligation to redeem 100% of the Class A ordinary
shares if it does not consummate an initial business combination by , 2023, or (iii) if the holder(s) seek(s) to redeem for cash
his, her or its respective Class A ordinary shares in connection with a tender offer (or proxy solicitation, solely in the event
the Company seeks shareholder 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.