Form of Common Stock Certificate.



 Exhibit 4.3 
  






 
 NUMBER 
AB 
ALDER BIOPHARMACEUTICALS 
INCORPORATED UNDER THE LAWS OF THE STATE OF DELAWARE 
SHARES 
CUSIP 014339 10 5 
SEE REVERSE FOR CERTAIN DEFINITIONS 
This certifies that 
is the record holder of 
FULLY PAID AND NONASSESSABLE SHARES OF COMMON STOCK, $0.0001 PAR
VALUE, OF 
Alder BioPharmaceuticals, Inc. 
transferable on the books of the
Corporation in person or by duly authorized attorney upon surrender of this Certificate properly endorsed. This Certificate is not valid until countersigned by the Transfer Agent and registered by the Registrar. 
WITNESS the facsimile seal of the Corporation and the facsimile signatures of its duly authorized officers. 
Dated: 
PRESIDENT 
ALDER BIOPHARMACEUTICALS, INC. 
CORPORATE 
SEAL 
MAY 20, 2002 
DELAWARE 
SECRETARY 
COUNTERSIGNED AND REGISTERED: 
AMERICAN STOCK TRANSFER & TRUST COMPANY, LLC

(NEW YORK, NY) TRANSFER AGENT 
AND REGISTRAR 
BY: 
AUTHORIZED SIGNATURE 







 The Corporation shall 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 of the Corporation or series thereof and the qualifications, limitations or restrictions of such preferences and/or rights.
Such requests shall be made to the Corporation’s Secretary at the principal office of the Corporation. 
 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	 		 		 	under Uniform Gifts to Minors
		 		 	survivorship and not as tenants	 		 		 	Act	 	  

		 		 	in common	 		 		 		 	(State)
	COM PROP	 	–	 	as community property	 	UNIF TRF MIN ACT	 	–	 	  
	 	Custodian (until age	 	  
	 	)
		 		 		 		 		 	(Cust)	 		 		 	
		 		 		 		 		 	  
	 	under Uniform Transfers
		 		 		 		 		 	(Minor)	 		 		 	
		 		 		 		 		 	to Minors Act	 	  

		 		 		 		 		 		 	(State)

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

					
	FOR VALUE RECEIVED,	 	  
	 	hereby sell(s), assign(s) and transfer(s) unto


  

					
	 PLEASE INSERT SOCIAL SECURITY OR OTHER IDENTIFYING NUMBER OF ASSIGNEE

 
	 		 	
	 	 		 	
	 	 		 	
	 	 		 	

  

			
	  

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

	
	  

		
	  
	 	shares
	of the capital stock represented by within Certificate, and do hereby irrevocably constitute and appoint


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

  

			
	Dated	 	  


  

									
		 		 	X	 	  

				
		 		 	X	 	  

	Signature(s) Guaranteed:	 		 		 	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 WHATSOEVER.

  

			
	By	 	  

	THE SIGNATURE(S) SHOULD 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. GUARANTEES BY A NOTARY PUBLIC ARE NOT ACCEPTABLE. SIGNATURE GUARANTEES MUST NOT BE DATED.