X0306 4 2021-02-05 0 0001785173 89bio, Inc. ETNB 0001300615 Mansbach Harry H C/O 89BIO, INC. 142 SANSOME STREET, 2ND FLOOR SAN FRANCISCO CA 94104 0 1 0 0 Chief Medical Officer Common Stock 2021-02-05 4 A 0 10000 0.00 A 10000 D Stock Option (Right to Buy) 23.01 2021-02-05 4 A 0 67500 0.00 A 2031-02-05 Common Stock 67500 67500 D Performance stock units vest with respect to 10,000 shares in three equal installments on the first, second and third anniversaries of February 5, 2021, subject to the achievement of specified milestone events and the Reporting Person's continued service to the Issuer. This option represents a right to purchase a total of 67,500 shares of the Issuer's Common Stock, one quarter of which will vest on February 5, 2022, with the remaining three quarters vesting in equal quarterly installments over the following three years, subject to the Reporting Person's continued service to the Issuer /s/ Ryan A. Murr, as attorney-in-fact for Harry H. Mansbach 2021-02-09