X0306 4 2020-12-15 0 0001826892 BioAtla, Inc. BCAB 0001834843 Short Carolyn Anderson C/O BIOATLA, INC. 11085 TORREYANA ROAD SAN DIEGO CA 92121 0 1 1 0 See Remarks Employee Stock Option (right to buy) 18.00 2020-12-15 4 A 0 7747 0.00 A 2030-12-15 Common Stock 7747 7747 D The option vests over a period of four years, with 25% of the shares underlying the option vesting on December 15, 2021, the first anniversary of the date of grant, and the remainder vesting in 36 substantially equal monthly installments thereafter, subject to the reporting person's continued employment through the applicable vesting dates. Chief of Intellectual Property and Strategy and Assistant Secretary /s/ Carolyn Anderson Short 2020-12-17