AnaptysBio Inc. Watch

from S-3 40 pages Anaptysbio, Inc. and , as Trustee Indenture Dated as of ,

from S-3 5 pages Form of Debt Security

from S-3 43 pages Anaptysbio, Inc. and , as Trustee Indenture Dated as of ,

from 10-K ~5 pages Description of the Registrant’s Securities Registered Pursuant to Section 12 of the Securities Exchange Act of 1934

from 10-Q 6 pages Amendment No. 1 to Fourth Amended and Restated Investor Rights Agreement

from S-3ASR 28 pages Anaptysbio, Inc. and , as Trustee Indenture Dated as of ,

from S-1/A 2 pages Number Ab Incorporated Under the Laws of the State of Delaware AnaptysBio Shares Cusip 032724 10 6 See Reverse for Certain Definitions This Certifies That Is the Record Holder of Fully Paid and Nonassessable Shares of Common Stock, $0.001 Par Value Per Share, of Anaptysbio, 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, Chief Executive Officer & Secretary Anaptysbio, Inc. Corporate Seal November 16, 2005 * Delaware * Chief Financial Officer Countersigned and Registered: American Stock Transfer & Trust Company, LLC (Brooklyn, Ny) Transfer Agent and Registrar By: Authorized Signature

from S-1 48 pages Anaptysbio, Inc. Fourth Amended and Restated Investor Rights Agreement

from DRS 48 pages Anaptysbio, Inc. Fourth Amended and Restated Investor Rights Agreement