X0306 4 2020-04-05 0 0001785173 89bio, Inc. ETNB 0001352908 Hayden Michael R C/O 89BIO, INC. 142 SANSOME STREET, 2ND FLOOR SAN FRANCISCO CA 94104 1 0 0 0 Stock Option (Right to Buy) 21.40 2020-04-05 4 A 0 7000 0.00 A 2030-04-05 Common Stock 7000 7000 D This option represents a right to purchase a total of 7,000 shares of the Issuer's Common Stock, one third of which will vest on April 5, 2021, with the remaining two thirds vesting in equal monthly installments over the following two years, subject to the Reporting Person's continued service to the Issuer through each vesting date. /s/ Ryan A. Murr, as attorney-in-fact for Michael R. Hayden 2020-04-07