X0306 4 2015-02-13 0 0001269021 PORTOLA PHARMACEUTICALS INC PTLA 0001192591 HOMCY CHARLES J C/O PORTOLA PHARMACEUTICALS, INC. 270 EAST GRAND AVE. SOUTH SAN FRANCISCO CA 94080 1 0 0 0 Common Stock 2015-02-13 4 M 0 20000 3.30 A 20000 D Common Stock 2015-02-13 4 S 0 20000 34.0487 D 0 D Stock Option (Right to Buy) 3.30 2015-02-13 4 M 0 20000 0.00 D 2006-09-06 2016-09-06 Common Stock 20000 210067 D The sales reported on this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on December 9, 2014. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $33.90 to $34.125, 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 ranges set forth in this Form 4. /s/ Mike Ouimette, as attorney-in-fact 2015-02-13