IDEAYA Biosciences, Inc. — Director's Dealing 2019

May 23, 2019

SEC Form 3 — Initial Statement of Beneficial Ownership

Issuer: IDEAYA Biosciences, Inc. (IDYA)
CIK: 0001676725
Period of Report: 2019-05-22

Reporting Person: Hambleton Julie (SVP, Chief Medical Officer)

Holdings (Derivative)

Security	Exercise Price	Expiration	Underlying	Shares	Ownership
Stock Option (right to buy)	$4.62	2028-06-20	Common Stock (155932)		Direct
Stock Option (right to buy)	$11.08	2029-03-13	Common Stock (23400)		Direct

Footnotes

F1: 25% of the shares subject to the option vest on the first anniversary measured from June 1, 2018 (the "Vesting Commencement Date"), and 1/48th of the total number of shares vest monthly thereafter, such that 100% of the shares subject to the option will be fully vested and exercisable on the fourth anniversary of the Vesting Commencement Date.

F2: 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.

F3: 25% of the shares subject to the option vest on the first anniversary measured from February 19, 2019 (the "Vesting Commencement Date"), and 1/48th of the total number of shares vest monthly thereafter, such that 100% of the shares subject to the option will be fully vested and exercisable on the fourth anniversary of the Vesting Commencement Date.