X0306 4 2019-01-15 0 0001370053 ANAPTYSBIO INC ANAB 0001654500 Londei Marco C/O ANAPTYSBIO, INC. 10421 PACIFIC CENTER COURT, SUITE 200 SAN DIEGO CA 92121 0 1 0 0 Chief Medical Officer Common Stock 2018-12-26 5 G 0 E 122500 0.00 D 22377 D Common Stock 2019-01-15 4 M 0 19075 6.93 A 41452 D Common Stock 2019-01-15 4 S 0 4181 69.2864 D 37271 D Common Stock 2019-01-15 4 S 0 14894 70.0413 D 22377 D Employee Stock Option (Right to Buy) 6.93 2019-01-15 4 M 0 19075 0.00 D 2025-08-13 Common Stock 19075 51148 D Represents the number of shares of Issuer's common stock that were donated as a charitable contribution. The reporting person does not exercise voting or dispositive powers, directly or indirectly, over the donated shares following this transfer. The transactions reported on this Form 4 were effected pursuant to a 10b5-1 trading plan adopted by the reporting person. The reported price in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $68.63 to $69.60 per share, inclusive. The reporting person undertakes to provide to the issuer, any security holder of the issuer, or the staff of the Securities and Exchange Commission, upon written request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote. The reported price in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $69.63 to $70.37 per share, inclusive. The reporting person undertakes to provide to the issuer, any security holder of the issuer, or the staff of the Securities and Exchange Commission, upon written request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote. The stock option vested and became exercisable as to 25% of the shares subject to the option on August 13, 2016, and thereafter vests as to 1/48th of the shares in equal monthly installments, until such time as the option is 100% vested, subject to the continuing employment of the Reporting Person on each vesting date. In addition to the remaining options to purchase 51,148 shares of common stock as set forth in Table II above, the Reporting Person also holds (i) additional options to purchase up to an aggregate of 148,060 shares of common stock, which options vest according to their terms, and (ii) 22,377 shares of common stock held directly. /s/Eric Loumeau, attorney-in-fact 2019-01-16