X0306 4 2021-10-22 0 0001581280 Twist Bioscience Corp TWST 0001753670 Banyai William C/O TWIST BIOSCIENCE CORPORATION 681 GATEWAY BLVD. SOUTH SAN FRANCISCO CA 94080 1 1 0 0 See Remarks Common Stock 2021-10-22 4 F 0 288 117.41 D 326169 D Common Stock 2021-10-25 4 S 0 1335 115.7896 D 324834 D Common Stock 2021-10-25 4 S 0 863 117.1300 D 323971 D Common Stock 2021-10-25 4 S 0 7619 117.9605 D 316352 D Common Stock 2021-10-25 4 S 0 9974 118.6762 D 306378 D Represents shares withheld by the Issuer to satisfy the Reporting Person's tax withholding obligation in connection with the vesting of certain Restricted Stock Units ("RSUs") previously granted to the Reporting Person. Such withholding is exempt from Section 16(b) pursuant to Rule 16b-3(e). The transactions reported on this Form 4 were effected pursuant to a Rule 10b5-1 trading plan previously adopted by the Reporting Person on August 28, 2020. Represents the weighted average sales price per share. The shares sold at prices ranging from $115.37 to $116.30 per share. Full information regarding the number of shares sold at each price shall be provided upon request to the staff of the U.S. Securities and Exchange Commission, the Issuer, or a security holder of the Issuer. Represents the weighted average sales price per share. The shares sold at prices ranging from $116.44 to $117.40 per share. Full information regarding the number of shares sold at each price shall be provided upon request to the staff of the U.S. Securities and Exchange Commission, the Issuer, or a security holder of the Issuer. Represents the weighted average sales price per share. The shares sold at prices ranging from $117.44 to $118.43 per share. Full information regarding the number of shares sold at each price shall be provided upon request to the staff of the U.S. Securities and Exchange Commission, the Issuer, or a security holder of the Issuer. Represents the weighted average sales price per share. The shares sold at prices ranging from $118.44 to $118.94 per share. Full information regarding the number of shares sold at each price shall be provided upon request to the staff of the U.S. Securities and Exchange Commission, the Issuer, or a security holder of the Issuer. Senior Vice President of Advanced Development and General Manager of Data Storage /s/ William Solis, as Attorney-in-Fact for William Banyai 2021-10-26