X0306 4 2018-07-28 0 0001269021 PORTOLA PHARMACEUTICALS INC PTLA 0001574558 Lis William C/O PORTOLA PHARMACEUTICALS, INC. 270 EAST GRAND AVE. SOUTH SAN FRANCISCO CA 94080 1 1 0 0 Chief Executive Officer Common Stock 2018-07-28 4 M 0 35000 0.00 A 222035 D Common Stock 2018-08-23 4 F 0 17587 26.05 D 204448 D Each Performance Stock Unit ("PSU") granted on January 27, 2015 pursuant to the Issuer's 2013 Equity Incentive Plan represented a contingent right to receive one share of Issuer's Common Stock. These PSUs were earned based on achievement of the market performance conditions and were subject to an additional one year period of service. 50% of the PSUs vested on July 28, 2018 and 50% will vest on August 31, 2018. Represents the number of shares required to be sold by the reporting person to cover tax withholding obligations in connection with the vesting of Performance Stock Units. This sale is mandated by the Issuer's election under its equity incentive plans to require the satisfaction of tax withholding obligations to be funded by a "sell to cover" transaction and does not represent a discretionary trade by the reporting person. The sale is intended to comply with the requirements of Rule 10b5-1(c)(1)(i)(B) under the Exchange Act and be interpreted to meet the requirements of Rule 10b5-1(c). /s/ Mike Ouimette, as attorney-in-fact 2018-08-28