X0306 4 2018-03-08 0 0001269021 PORTOLA PHARMACEUTICALS INC PTLA 0001574591 Dier Mardi C/O PORTOLA PHARMACEUTICALS, INC. 270 EAST GRAND AVENUE SOUTH SAN FRANCISCO CA 94080 0 1 0 0 Executive VP and CFO Common Stock 2018-03-08 4 D 0 10465 38.6875 D 63451 D Common Stock 2018-03-08 4 D 0 2009 39.1571 D 61442 D The sales reported on this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on September 18, 2017. The price reported is a weighted average price. These shares were sold in multiple transactions at prices ranging from $38.05 to $39.02, inclusive. The reporting person undertakes to provide Portola Pharmaceuticals, Inc., any security holder of Portola Pharmaceuticals, Inc., or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in footnotes (2) and (4) to this Form 4. This number includes 31,040 unvested RSUs. The price reported is a weighted average price. These shares were sold in multiple transactions at prices ranging from $39.06 to $39.28, inclusive. The reporting person undertakes to provide Portola Pharmaceuticals, Inc., any security holder of Portola Pharmaceuticals, Inc., or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in footnotes (2) and (4) to this Form 4. This number includes 31,040 unvested RSUs. /s/ Mike Ouimette, as attorney-in-fact 2018-03-12