SEC Form DEFA14A filed by IDEAYA Biosciences Inc.

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, DC 20549

SCHEDULE 14A

(Rule 14a-101)

INFORMATION REQUIRED IN PROXY STATEMENT

SCHEDULE 14A INFORMATION

Proxy Statement Pursuant to Section 14(a) of the

Securities Exchange Act of 1934

(Amendment No. )

Filed by the Registrant ☒     Filed by a Party other than the Registrant ☐

Check the appropriate box:

IDEAYA BIOSCIENCES, INC.

(Name of Registrant as Specified in its Charter)

(Name of Person(s) Filing Proxy Statement, if Other Than the Registrant)

Payment of Filing Fee (Check all boxes that apply):

P.O. BOX 8016, CARY, NC 27512-9903 Your vote matters! Meeting Materials: Notice of Meeting and Proxy Statement & Annual Report or Form 10-K Important Notice Regarding the Availability of Proxy Materials for the Stockholders IDEAYA Biosciences, Inc. Meeting To Be Held On June 16, 2026 For Stockholders of record as of April 20, 2026 Annual Meeting of Stockholders To order paper materials, use one of the Tuesday, June 16, 2026 1:30 PM, Pacific Time Annual Meeting to be held live via the internet—please visit www.proxydocs.com/IDYA for following methods. more information. You must register by June 15, 2026, 5:00PM ET to attend the meeting online. Please visit www.proxydocs.com/IDYA Internet: For a convenient way to view proxy materials, VOTE, and obtain www.investorelections.com/IDYA directions to attend the meeting go to www.proxydocs.com/IDYA To vote your proxy while visiting this site, you will need the 12 digit control number in the box below. Call: 1-866-648-8133 This communication presents only an overview of the more complete proxy materials that are available to you on the Internet. This is not a ballot. You cannot use this notice to vote your shares. We encourage you to access and review all of the important information contained in the proxy materials before voting. Email: paper@investorelections.com Under United States Securities and Exchange Commission rules, proxy materials do not have to be delivered in paper. Proxy materials can be distributed by making them available on the * If requesting material by e-mail, please send a blank e-mail with the internet. 12 digit control number (located below) in the subject line. No other requests, instructions OR other inquiries should be included with your If you want to receive a paper or e-mail copy of the proxy material, you must request one. e-mail requesting material. There is no charge to you for requesting a copy. In order to receive a paper package in time for this year’s meeting, you must make this request on or before . Your control number Have the 12 digit control number located in the box above available when you access the website and follow the instructions. SEE REVERSE FOR FULL AGENDA Copyright © 2026 BetaNXT, Inc. or its affiliates. All Rights Reserved 

IDEAYA Biosciences, Inc. Annual Meeting of Stockholders THE BOARD OF DIRECTORS RECOMMENDS A VOTE: FOR ON PROPOSALS 1, 2 AND 3 PROPOSAL 1. To elect three Class I directors to hold office until the 2029 annual meeting of stockholders or until their successors are elected; 1.01 Yujiro S. Hata 1.02 M. Garret Hampton, Ph.D. 1.03 Catherine J. Mackey, Ph.D. 2. To ratify the selection, by the Audit Committee of the Company’s Board of Directors, of PricewaterhouseCoopers LLP, as the independent registered public accounting firm of the Company for its fiscal year ending December 31, 2026; 3. To approve, on a non-binding, advisory basis, the compensation of the Company’s named executive officers as disclosed in the Proxy Statement accompanying this Notice of Annual Meeting of Stockholders; and 4. To transact such other business as may properly come before the Annual Meeting or any adjournment or postponement thereof.