X0306 4 2018-06-06 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 2018-06-06 4 S 0 5113 45.21 D 222035 D The sales reported on this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on October 13, 2017, as amended. The price reported is a weighted average price. These shares were sold in multiple transactions at prices ranging from $45.00 to $45.54, 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 the footnote to this Form 4. /s/ Mike Ouimette, as attorney-in-fact 2018-06-08