IDEAYA Biosciences, Inc. — Director's Dealing 2021

May 13, 2021

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: IDEAYA Biosciences, Inc. (IDYA)
CIK: 0001676725
Period of Report: 2021-05-11

Reporting Person: Dillon Michael P. (SVP, Chief Scientific Officer)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2021-05-11	Common Stock	M	5000	$6.92	Acquired	103789	Direct
2021-05-11	Common Stock	S	5000	$20.2185	Disposed	98789	Direct

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2021-05-11	Stock Option (right to buy)	$6.92	M	5000	Disposed	2030-02-20	Common Stock (5000)	Direct

Footnotes

F1: The transactions reported herein were effected pursuant to the Reporting Person's Rule 10b5-1 trading plan.

F2: This transaction was executed in multiple trades in prices ranging from $19.97 to $20.76, inclusive. The price reported in Column 4 above reflects the weighted average sale price. The Reporting Person hereby undertakes to provide to the Securities and Exchange Commission staff, the Issuer, or a security holder of the Issuer, upon request, full information regarding the number of shares sold at each respective price within the range set forth in this footnote.

F3: 25% of the shares subject to the option vest on the first anniversary measured from January 1, 2020 (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.