X0206 3 2019-05-22 0 0001676725 IDEAYA Biosciences, Inc. IDYA 0001207114 SHANNON TIMOTHY M C/O CANAAN PARTNERS 285 RIVERSIDE AVENUE, SUITE 250 WESTPORT CT 06880 1 0 0 0 Series A Preferred Stock Common Stock 1658164 I See footnote Series B Preferred Stock Common Stock 602549 I See footnote Reflects a 1-for-10.2564 reverse stock split of the Issuer's outstanding securities effected prior to the effectiveness of the Issuer's S-1 Registration Statement. The reported securities are held directly by Canaan X L.P. (the "Canaan Fund"). The sole general partner of the Canaan Fund is Canaan Partners X LLC ("Canaan X", and together with the Canaan Fund, the "Canaan Entities"), and may be deemed to have sole voting, investment and dispositive power with respect to the shares held by the Canaan Fund. The Reporting Person is a manager and member of Canaan X. The Reporting Person disclaims Section 16 beneficial ownership in the securities held by the Canaan Entities, except to the extent of his pecuniary interest therein, if any, in such securities by virtue of the limited liability company interest he owns in Canaan X. Each share of Series A Preferred Stock will automatically convert on a 1-for-1 basis into Common Stock immediately prior to the closing of the Issuer's initial public offering. Each share of Series B Preferred Stock will automatically convert on a 1-for-1 basis into Common Stock immediately prior to the closing of the Issuer's initial public offering. Exhibit 24 - Power of Attorney filed herewith. /s/ Janine MacDonald, Attorney-in-Fact for Timothy M. Shannon 2019-05-22