BCAB · BioAtla, Inc.

This transaction is not a sale of shares by the Reporting Person. Instead, this represents shares that have been withheld by the Issuer to satisfy its income tax and withholding and remittance obligations in connection with the vesting and net settlement of previously reported restricted stock units.

Effective on April 6, 2026, the Issuer effected a 50-for-1 share consolidation of its common stock (the "Share Consolidation"). The amount of securities reported on this Form 4 has been adjusted to reflect the Share Consolidation.

This transaction is not a sale of shares by the Reporting Person. Instead, this represents shares that have been withheld by the Issuer to satisfy its income tax and withholding and remittance obligations in connection with the vesting and net settlement of previously reported restricted stock units.

Effective on April 6, 2026, the Issuer effected a 50-for-1 share consolidation of its common stock (the "Share Consolidation"). The amount of securities reported on this Form 4 has been adjusted to reflect the Share Consolidation.

This transaction is not a sale of shares by the Reporting Person. Instead, this represents shares that have been withheld by the Issuer to satisfy its income tax and withholding and remittance obligations in connection with the vesting and net settlement of previously reported restricted stock units.

Effective on April 6, 2026, the Issuer effected a 50-for-1 share consolidation of its common stock (the "Share Consolidation"). The amount of securities reported on this Form 4 has been adjusted to reflect the Share Consolidation.

This transaction is not a sale of shares by the Reporting Person. Instead, this represents shares that have been withheld by the Issuer to satisfy its income tax and withholding and remittance obligations in connection with the vesting and net settlement of previously reported restricted stock units.

Effective on April 6, 2026, the Issuer effected a 50-for-1 share consolidation of its common stock (the "Share Consolidation"). The amount of securities reported on this Form 4 has been adjusted to reflect the Share Consolidation.

This transaction is not a sale of shares by the Reporting Person. Instead, this represents shares that have been withheld by the Issuer to satisfy its income tax and withholding and remittance obligations in connection with the vesting and net settlement of previously reported restricted stock units.

Effective on April 6, 2026, the Issuer effected a 50-for-1 share consolidation of its common stock (the "Share Consolidation"). The amount of securities reported on this Form 4 has been adjusted to reflect the Share Consolidation.

Represents shares of Common Stock underlying a time-based restricted stock unit award ("RSU"). The RSU will vest as to 25% of the total number of shares on March 11, 2027, and thereafter, 6.25% of the total number of shares subject to the RSU shall vest on the last day of each May, August, November and February, subject to the reporting person's continued service through the applicable vesting date.

This transaction is not a sale of shares by the Reporting Person. Instead, this represents shares that have been withheld by the Issuer to satisfy its income tax and withholding and remittance obligations in connection with the vesting and net settlement of previously reported restricted stock units.

Effective on April 6, 2026, the Issuer effected a 50-for-1 share consolidation of its common stock (the "Share Consolidation"). The amount of securities reported on this Form 4 has been adjusted to reflect the Share Consolidation.

Represents shares of Common Stock underlying a time-based restricted stock unit award ("RSU"). The RSU will vest as to 25% of the total number of shares on March 10, 2027, and thereafter, 6.25% of the total number of shares subject to the RSU shall vest on the last day of each May, August, November and February, subject to the reporting person's continued service through the applicable vesting date.

Represents shares of Common Stock underlying a time-based restricted stock unit award ("RSU"). The RSU will vest as to 25% of the total number of shares on March 10, 2027, and thereafter, 6.25% of the total number of shares subject to the RSU shall vest on the last day of each May, August, November and February, subject to the reporting person's continued service through the applicable vesting date.

This transaction is not a sale of shares by the Reporting Person. Instead, this represents shares that have been withheld by the Issuer to satisfy its income tax and withholding and remittance obligations in connection with the vesting and net settlement of previously reported restricted stock units.

This transaction is not a sale of shares by the Reporting Person. Instead, this represents shares that have been withheld by the Issuer to satisfy its income tax and withholding and remittance obligations in connection with the vesting and net settlement of previously reported restricted stock units.

This transaction is not a sale of shares by the Reporting Person. Instead, this represents shares that have been withheld by the Issuer to satisfy its income tax and withholding and remittance obligations in connection with the vesting and net settlement of previously reported restricted stock units.

This transaction is not a sale of shares by the Reporting Person. Instead, this represents shares that have been withheld by the Issuer to satisfy its income tax and withholding and remittance obligations in connection with the vesting and net settlement of previously reported restricted stock units.

This transaction is not a sale of shares by the Reporting Person. Instead, this represents shares that have been withheld by the Issuer to satisfy its income tax and withholding and remittance obligations in connection with the vesting and net settlement of previously reported restricted stock units.

Includes shares purchased under the Issuer's ESPP.

This transaction is not a sale of shares by the Reporting Person. Instead, this represents shares that have been withheld by the Issuer to satisfy its income tax and withholding and remittance obligations in connection with the vesting and net settlement of previously reported restricted stock units.

This transaction is not a sale of shares by the Reporting Person. Instead, this represents shares that have been withheld by the Issuer to satisfy its income tax and withholding and remittance obligations in connection with the vesting and net settlement of previously reported restricted stock units.

This transaction is not a sale of shares by the Reporting Person. Instead, this represents shares that have been withheld by the Issuer to satisfy its income tax and withholding and remittance obligations in connection with the vesting and net settlement of previously reported restricted stock units.

Includes shares purchased under the Issuer's ESPP.

This transaction is not a sale of shares by the Reporting Person. Instead, this represents shares that have been withheld by the Issuer to satisfy its income tax and withholding and remittance obligations in connection with the vesting and net settlement of previously reported restricted stock units.

This transaction is not a sale of shares by the Reporting Person. Instead, this represents shares that have been withheld by the Issuer to satisfy its income tax and withholding and remittance obligations in connection with the vesting and net settlement of previously reported restricted stock units.

This transaction is not a sale of shares by the Reporting Person. Instead, this represents shares that have been withheld by the Issuer to satisfy its income tax and withholding and remittance obligations in connection with the vesting and net settlement of previously reported restricted stock units.

This transaction is not a sale of shares by the Reporting Person. Instead, this represents shares that have been withheld by the Issuer to satisfy its income tax and withholding and remittance obligations in connection with the vesting and net settlement of previously reported restricted stock units.

Represents shares of Common Stock underlying a time-based restricted stock unit award ("RSU"). The RSU will vest as to 100% of the total number of shares on the earlier of (i) June 18, 2026, or (ii) the next Company annual meeting of stockholders, subject to the reporting person's continued service through the vesting date.

Represents shares of Common Stock underlying a time-based restricted stock unit award ("RSU"). The RSU will vest as to 100% of the total number of shares on the earlier of (i) June 18, 2026, or (ii) the next Company annual meeting of stockholders, subject to the reporting person's continued service through the vesting date.

Represents shares of Common Stock underlying a time-based restricted stock unit award ("RSU"). The RSU will vest as to 100% of the total number of shares on the earlier of (i) June 18, 2026, or (ii) the next Company annual meeting of stockholders, subject to the reporting person's continued service through the vesting date.

Represents shares of Common Stock underlying a time-based restricted stock unit award ("RSU"). The RSU will vest as to 100% of the total number of shares on the earlier of (i) June 18, 2026, or (ii) the next Company annual meeting of stockholders, subject to the reporting person's continued service through the vesting date.

Represents shares of Common Stock underlying a time-based restricted stock unit award ("RSU"). The RSU will vest as to 100% of the total number of shares on the earlier of (i) June 18, 2026, or (ii) the next Company annual meeting of stockholders, subject to the reporting person's continued service through the vesting date.

Represents shares of Common Stock underlying a time-based restricted stock unit award ("RSU"). The RSU will vest as to 100% of the total number of shares on the earlier of (i) June 18, 2026, or (ii) the next Company annual meeting of stockholders, subject to the reporting person's continued service through the vesting date.

This transaction is not a sale of shares by the Reporting Person. Instead, this represents shares that have been withheld by the Issuer to satisfy its income tax and withholding and remittance obligations in connection with the vesting and net settlement of previously reported restricted stock units.

This transaction is not a sale of shares by the Reporting Person. Instead, this represents shares that have been withheld by the Issuer to satisfy its income tax and withholding and remittance obligations in connection with the vesting and net settlement of previously reported restricted stock units.

Includes shares purchased under the Issuer's ESPP Plan.

This transaction is not a sale of shares by the Reporting Person. Instead, this represents shares that have been withheld by the Issuer to satisfy its income tax and withholding and remittance obligations in connection with the vesting and net settlement of previously reported restricted stock units.

Includes shares purchased under the Issuer's ESPP Plan.

This transaction is not a sale of shares by the Reporting Person. Instead, this represents shares that have been withheld by the Issuer to satisfy its income tax and withholding and remittance obligations in connection with the vesting and net settlement of previously reported restricted stock units.

Represents shares of Common Stock underlying a time-based restricted stock unit award ("RSU"). The RSU will vest as to 25% of the total number of shares on March 11, 2026, and thereafter, 6.25% of the total number of shares subject to the RSU shall vest on the last day of each May, August, November and February so long as the reporting person remains a service provider.

Represents shares of Common Stock underlying a time-based restricted stock unit award ("RSU"). The RSU will vest as to 25% of the total number of shares on March 11, 2026, and thereafter, 6.25% of the total number of shares subject to the RSU shall vest on the last day of each May, August, November and February so long as the reporting person remains a service provider.

Represents shares of Common Stock underlying a time-based restricted stock unit award ("RSU"). The RSU will vest as to 25% of the total number of shares on March 11, 2026, and thereafter, 6.25% of the total number of shares subject to the RSU shall vest on the last day of each May, August, November and February so long as the reporting person remains a service provider.

Represents shares of Common Stock underlying a time-based restricted stock unit award ("RSU"). The RSU will vest as to 25% of the total number of shares on March 11, 2026, and thereafter, 6.25% of the total number of shares subject to the RSU shall vest on the last day of each May, August, November and February so long as the reporting person remains a service provider.

This transaction is not a sale of shares by the Reporting Person. Instead, this represents shares that have been withheld by the Issuer to satisfy its income tax and withholding and remittance obligations in connection with the vesting and net settlement of previously reported restricted stock units.

This transaction is not a sale of shares by the Reporting Person. Instead, this represents shares that have been withheld by the Issuer to satisfy its income tax and withholding and remittance obligations in connection with the vesting and net settlement of previously reported restricted stock units.

Includes shares purchased under the Issuer's ESPP Plan.

This transaction is not a sale of shares by the Reporting Person. Instead, this represents shares that have been withheld by the Issuer to satisfy its income tax and withholding and remittance obligations in connection with the vesting and net settlement of previously reported restricted stock units.

Includes shares purchased under the Issuer's ESPP Plan.

This transaction is not a sale of shares by the Reporting Person. Instead, this represents shares that have been withheld by the Issuer to satisfy its income tax and withholding and remittance obligations in connection with the vesting and net settlement of previously reported restricted stock units.

This transaction is not a sale of shares by the Reporting Person. Instead, this represents shares that have been withheld by the Issuer to satisfy its income tax and withholding and remittance obligations in connection with the vesting and net settlement of previously reported restricted stock units.

This transaction is not a sale of shares by the Reporting Person. Instead, this represents shares that have been withheld by the Issuer to satisfy its income tax and withholding and remittance obligations in connection with the vesting and net settlement of previously reported restricted stock units.

This transaction is not a sale of shares by the Reporting Person. Instead, this represents shares that have been withheld by the Issuer to satisfy its income tax and withholding and remittance obligations in connection with the vesting and net settlement of previously reported restricted stock units.

This transaction is not a sale of shares by the Reporting Person. Instead, this represents shares that have been withheld by the Issuer to satisfy its income tax and withholding and remittance obligations in connection with the vesting and net settlement of previously reported restricted stock units.

This transaction is not a sale of shares by the Reporting Person. Instead, this represents shares that have been withheld by the Issuer to satisfy its income tax and withholding and remittance obligations in connection with the vesting and net settlement of previously reported restricted stock units.

This transaction is not a sale of shares by the Reporting Person. Instead, this represents shares that have been withheld by the Issuer to satisfy its income tax and withholding and remittance obligations in connection with the vesting and net settlement of previously reported restricted stock units.

Represents shares of Common Stock underlying a time-based restricted stock unit award ("RSU"). The RSU will vest as to 100% of the total number of shares on the earlier of (i) June 13, 2025, and (ii) the next Company annual meeting of stockholders, subject to the reporting person's continued service through the vesting date.

Represents shares of Common Stock underlying a time-based restricted stock unit award ("RSU"). The RSU will vest as to 100% of the total number of shares on the earlier of (i) June 13, 2025, and (ii) the next Company annual meeting of stockholders, subject to the reporting person's continued service through the vesting date.

Represents shares of Common Stock underlying a time-based restricted stock unit award ("RSU"). The RSU will vest as to 100% of the total number of shares on the earlier of (i) June 13, 2025, and (ii) the next Company annual meeting of stockholders, subject to the reporting person's continued service through the vesting date.

Represents shares of Common Stock underlying a time-based restricted stock unit award ("RSU"). The RSU will vest as to 100% of the total number of shares on the earlier of (i) June 13, 2025, and (ii) the next Company annual meeting of stockholders, subject to the reporting person's continued service through the vesting date.

Represents shares of Common Stock underlying a time-based restricted stock unit award ("RSU"). The RSU will vest as to 100% of the total number of shares on the earlier of (i) June 13, 2025, and (ii) the next Company annual meeting of stockholders, subject to the reporting person's continued service through the vesting date.