Form of Common Stock Certificate



 Exhibit 4.1 
  



 
  
 Exhibit 4.1

 COUNTERSIGNED AND REGISTERED: 
 AMERICAN STOCK TRANSFER & TRUST COMPANY 
 (NEW YORK, NY) 
 TRANSFER AGENT AND REGISTRAR 
 BY 
 COMMON STOCK 
 COMMON STOCK 
 SEE REVERSE FOR 
 CERTAIN DEFINITIONS 
 CUSIP 45665G 30 3 
 Infinity Pharmaceuticals, Inc. 
 INCORPORATED UNDER THE LAWS OF THE STATE OF DELAWARE 
 THIS CERTIFIES THAT 
 SPECIMEN 
 is the owner of 
 FULLY PAID AND NON-ASSESSABLE SHARES OF COMMON STOCK, $0.001 PAR VALUE, OF 
 INFINITY PHARMACEUTICALS, INC.

 transferable on the books of the corporation by such owner in person or by attorney upon surrender of this certificate duly
endorsed or assigned. This certificate and the shares represented hereby are subject to the laws of the State of Delaware and the Certificate of Incorporation and By-Laws of the corporation, as now in effect or hereinafter amended. This certificate
is not valid until countersigned and registered by the Transfer Agent and Registrar. 
 WITNESS the facsimile seal of the
corporation and the facsimile signatures of its duly authorized officers. 
 Dated: 
 SECRETARY 
 PRESIDENT 
 AUTHORISED SIGNATURE 
 AMERICAN BANK NOTE COMPANY. 







 INFINITY PHARMACEUTICALS, INC. 
  
 The Corporation is authorized to issue more than one class of stock. The Corporation 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 stock or series thereof of the Corporation, and the qualifications, limitations or
restrictions of such preferences and/or rights. 
  
 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 sell, assign and transfer, unto 
  

			
	 PLEASE INSERT SOCIAL SECURITY OR OTHER
 IDENTIFYING NUMBER OF ASSIGNEE
	  	 
	 	
	 	  	 
	
	 
	Please print or typewrite name and address, including postal zip code, of assignee
	
	 
	
	 


					
		
	 	  	Shares
	of the Common Stock represented by the within Certificate, and do hereby irrevocably constitute and appoint


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


			
	 	 	 

  

	
	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.

  
 KEEP THIS CERTIFICATE IN A SAFE
PLACE, IF IT IS LOST, STOLEN, MUTILATED OR DESTROYED, THE CORPORATION MAY REQUIRE A BOND OF INDEMNITY AS A CONDITION TO THE ISSUANCE OF A REPLACEMENT CERTIFICATE. 
  
 NOTICE: The signature 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.