X0306 4 2021-11-30 0 0001826892 BioAtla, Inc. BCAB 0001226961 WALDRON RICHARD A C/O BIOATLA, INC. 11085 TORREYANA ROAD SAN DIEGO CA 92121 0 1 0 0 Chief Financial Officer Common Stock 2021-11-30 2021-12-03 4 S 0 2240 23.997 D 146419 D Common Stock 2021-11-30 2021-12-03 4 S 0 2422 24.676 D 143997 D Common Stock 2021-11-30 2021-12-03 4 S 0 848 25.379 D 143149 D Common Stock 2021-12-01 2021-12-06 4 S 0 2332 22.186 D 140817 D Common Stock 2021-12-01 2021-12-06 4 S 0 4034 23.266 D 136783 D Common Stock 2021-12-01 2021-12-06 4 S 0 880 24.224 D 135903 D Common Stock 2021-12-02 2021-12-06 4 S 0 1405 21.741 D 134498 D Common Stock 2021-12-02 2021-12-06 4 S 0 29 22.471 D 134469 D Represents shares of the Issuer's common stock sold by the reporting person to cover taxes due upon the release and settlement of the vested RSUs. The range of prices for the shares of Common Stock is from $23.33 to $24.32. The reporting person undertakes that he will provide, upon request by the staff of the U.S. Securities and Exchange Commission, full information regarding the number of securities sold at each separate price. The range of prices for the shares of Common Stock is from $24.33 to $25.25. The reporting person undertakes that he will provide, upon request by the staff of the U.S. Securities and Exchange Commission, full information regarding the number of securities sold at each separate price. The range of prices for the shares of Common Stock is from $25.30 to $25.38. The reporting person undertakes that he will provide, upon request by the staff of the U.S. Securities and Exchange Commission, full information regarding the number of securities sold at each separate price. The range of prices for the shares of Common Stock is from $21.79 to $22.73. The reporting person undertakes that he will provide, upon request by the staff of the U.S. Securities and Exchange Commission, full information regarding the number of securities sold at each separate price. The range of prices for the shares of Common Stock is from $22.79 to $23.77. The reporting person undertakes that he will provide, upon request by the staff of the U.S. Securities and Exchange Commission, full information regarding the number of securities sold at each separate price. The range of prices for the shares of Common Stock is from $23.80 to $24.68. The reporting person undertakes that he will provide, upon request by the staff of the U.S. Securities and Exchange Commission, full information regarding the number of securities sold at each separate price. The range of prices for the shares of Common Stock is from $21.40 to $22.37. The reporting person undertakes that he will provide, upon request by the staff of the U.S. Securities and Exchange Commission, full information regarding the number of securities sold at each separate price. The range of prices for the shares of Common Stock is from $22.40 to $22.51. The reporting person undertakes that he will provide, upon request by the staff of the U.S. Securities and Exchange Commission, full information regarding the number of securities sold at each separate price. /s/ Christian Vasquez, as Attorney-in-Fact for Richard A. Waldron 2021-12-07