BioAtla, Inc.

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 14A

Proxy Statement Pursuant to Section (a) of the

Securities Exchange Act of 1934

(Amendment No.)

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Filed by a Party other than the Registrant☐

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☐ Preliminary Proxy Statement

☐ Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2))

☒ Definitive Proxy Statement

☐ Definitive Additional Materials

☐ Soliciting Material under §240.14a-12

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To Our Stockholders:

You are cordially invited to attend the 2025 Annual Meeting of Stockholders, or the Annual Meeting, of BioAtla, Inc. on Wednesday, June 18, 2025 at 8:00 a.m. Pacific Time. The Annual Meeting will be a completely virtual meeting, conducted only via live webcast on the internet at www.proxydocs.com/BCAB. There will be no physical location for the Annual Meeting. You will be able to attend and participate in the Annual Meeting online, submit questions during the meeting and vote your shares electronically. In addition, although the live webcast is available only to stockholders at the time of the meeting, following completion of the Annual Meeting, a webcast replay will be posted to the Investors—Events & Presentations section of our website at www.bioatla.com.

The matters expected to be acted upon at the Annual Meeting are described in the accompanying Notice of Annual Meeting of Stockholders and Proxy Statement. The Annual Meeting materials include the notice, the Proxy Statement, our Annual Report and the proxy card, each of which is enclosed.

Please use this opportunity to take part in our affairs by voting on the business to come before the Annual Meeting. You will receive a Notice of Internet Availability of Proxy Materials, or the Notice, which we expect to mail on or about May 2, 2025, unless you have previously requested to receive our proxy materials in paper form. Only stockholders of record at the close of business on April 21, 2025 may vote at the Annual Meeting and any postponements or adjournments of the meeting. All stockholders are cordially invited to participate in the Annual Meeting and any postponements or adjournments of the meeting. However, to ensure your representation at the Annual Meeting, please vote as soon as possible by using the internet or telephone, as instructed in the Notice. Alternatively, you may follow the procedures outlined in the Notice to request a paper proxy card to submit your vote by mail. Returning the paper proxy card or voting electronically does NOT deprive you of your right to participate in the virtual meeting and to vote your shares for the matters acted upon at the meeting.

Your vote is important. Whether or not you expect to attend and participate in the Annual Meeting, please submit your proxy electronically via the internet or by telephone by following the instructions in the Notice or if you asked to receive the proxy materials in paper form, please complete, sign and date the proxy card and return it in the postage paid envelope provided.

Sincerely,

/s/ Jay M. Short, Ph.D.

Jay M. Short, Ph.D.

Co-founder, Chief Executive Officer and Chairman of the Board of Directors

IMPORTANT NOTICE REGARDING THE AVAILABILITY OF PROXY MATERIALS FOR THE ANNUAL MEETING TO BE HELD ON JUNE 18, 2025: THE PROXY STATEMENT, PROXY CARD AND ANNUAL REPORT ON FORM 10-K FOR THE FISCAL YEAR ENDED DECEMBER 31, 2024 ARE AVAILABLE FREE OF CHARGE AT www.proxydocs.com/BCAB.

NOTICE OF ANNUAL MEETING OF STOCKHOLDERS

For questions regarding your stock ownership, you may contact us through our Investors/Resources/Contact IR section of our website www.bioatla.com or, if you are a registered holder, contact our transfer agent, Pacific Stock Transfer Company, by telephone at (702) 361-3033 or by email at info@pacificstocktransfer.com.

By Order of the Board of Directors,

/s/ Jay M. Short, Ph.D.

Jay M. Short, Ph.D.

Co-founder, Chief Executive Officer and Chairman of the Board of Directors

Table of Contents

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PROXY STATEMENT FOR THE 2025 ANNUAL MEETING OF STOCKHOLDERS

TO BE HELD ON WEDNESDAY, JUNE 18, 2025