X0306 4 2023-02-17 0 0001785173 89bio, Inc. ETNB 0001792018 Martins Ryan C/O 89BIO, INC. 142 SANSOME STREET, 2ND FLOOR SAN FRANCISCO CA 94104 0 1 0 0 Chief Financial Officer Common Stock 2023-02-17 4 F 0 1750 13.97 D 61118 D Common Stock 2023-02-21 4 S 0 2540 13.89 D 58578 D Represents shares withheld by the Issuer to satisfy tax withholding obligations in connection with the release of 4,290 restricted stock units on February 17, 2023. This transaction was executed pursuant to a Rule 10b5-1 trading plan in multiple trades at prices ranging from $13.72 to $14.32. The price reported above reflects the weighted average sales price. The reporting person hereby undertakes to provide upon request to the SEC staff, the Issuer or a security holder of the Issuer full information regarding the number of shares and prices at which the transaction was effected. /s/ Ryan A. Murr, as attorney-in-fact for Ryan Martins 2023-02-22