Exhibit 4.2


 


	NUMBER C-	SHARES
	SEE REVERSE FOR CERTAIN DEFINITIONS	 
	 	 
	 	CUSIP 02157P 101


 


ALTITUDE ACQUISITION CORP. III

CLASS A COMMON STOCK


 


THIS CERTIFIES THAT is the owner of fully
paid and non-assessable shares of Class A common stock, par value $0.0001 per share (the “Common Stock”),
of Altitude Acquisition Corp. III, a Delaware corporation (the “Company”), transferable on the books
of the Company in person or by duly authorized attorney upon surrender of this certificate properly endorsed.


 


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


 


Witness the facsimile signature of a duly
authorized signatory of the Company.


 


	Authorized Signatory	Transfer Agent



 

ALTITUDE ACQUISITION CORP. III


 


The Company will furnish without charge
to each stockholder who so requests, a statement of the powers, designations, preferences and relative, participating, optional
or other special rights of each class of equity 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 Company’s Amended and Restated Certificate of Incorporation, as the same may be amended from time
to time (the “Charter”) 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 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	 	 	 	 	 
	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 Common Stock represented by
the within Certificate, and hereby irrevocably constitutes and appoints 


 






     


     


    

 


Attorney to transfer the said shares of
Common Stock 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:	 
	 	 
	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 UNDER THE SECURITIES EXCHANGE ACT OF 1934, AS AMENDED (OR ANY SUCCESSOR RULE).	 


 


As more fully described in, and subject
to the terms and conditions described in, the Company’s final prospectus for its initial public offering 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 the Company’s initial public offering only in the event that (i) the Company redeems the shares
of Common Stock sold in the Company’s initial public offering and liquidates because it does not consummate an initial business
combination by the date set forth (the “Last Date”) in the Charter, as the same may be amended from time to time (the
“Charter”), (ii) the Company redeems the shares of Common Stock sold in its initial public offering properly submitted
in connection with a stockholder vote to amend the Charter to modify the substance or timing of the Company’s obligation
to redeem 100% of the Common Stock if it does not consummate an initial business combination by the Last Date or with respect to
any other material provisions 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 Company 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.