X0306 4 2019-07-23 0 0001581280 Twist Bioscience Corp TWST 0001222644 RAGUSA ROBERT P C/O TWIST BIOSCIENCE CORPORATION 455 MISSION BAY BOULEVARD SOUTH SAN FRANCISCO CA 94158 1 0 0 0 Director Stock Option (right to buy) 30.41 2019-07-23 4 A 0 5590 0.00 A 2029-07-22 Common Stock 5590 5590 D 100% of the shares subject to the option will vest and become exercisable on the earlier of (i) the one-year anniversary of the date of grant and (ii) the date of the Issuer's first annual meeting of stockholders following the date of grant, subject to the Reporting Person's continuous service through each vesting date. /s/ William Solis, as Attorney-in-Fact for Robert Ragusa 2019-10-09