BioAtla, Inc.

We have elected to utilize the “full set delivery” option. We are delivering to all stockholders paper copies of all of our proxy materials, including a proxy card, as well as providing access to all our proxy materials on a publicly accessible website. On or about December 5, 2025, we expect to mail our proxy materials to our stockholders of record at the close of business on November 25, 2025. Our proxy materials, including this Proxy Statement, form of proxy card, and Annual Report on Form 10-K for the year ended December 31, 2024 are available online at https://web.viewproxy.com/BCAB.

This Proxy Statement and the accompanying proxy card direct stockholders as to the date and the time of the Special Meeting and information on how to participate in and vote at the meeting; the matters to be acted upon at the meeting and our board of directors’ recommendations with regard to each matter; and instructions on how to vote.