IDEAYA Biosciences, Inc. — Director's Dealing 2019

May 29, 2019

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: IDEAYA Biosciences, Inc. (IDYA)
CIK: 0001676725
Period of Report: 2019-05-28

Reporting Person: 5AM Ventures IV, L.P. (10% Owner)
Reporting Person: 5AM Co-Investors IV, L.P. (10% Owner)
Reporting Person: 5AM Partners IV, LLC (10% Owner)
Reporting Person: ROCKLAGE SCOTT M (10% Owner)
Reporting Person: Schwab Andrew J. (10% Owner)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2019-05-28	Common Stock	C	1721898	—	Acquired	2026098	Indirect
2019-05-28	Common Stock	C	578447	—	Acquired	2604545	Indirect
2019-05-28	Common Stock	C	71745	—	Acquired	84420	Indirect
2019-05-28	Common Stock	C	24101	—	Acquired	108521	Indirect
2019-05-28	Common Stock	P	240000	$10.00	Acquired	2844545	Indirect
2019-05-28	Common Stock	P	10000	$10.00	Acquired	118521	Indirect
2019-05-28	Common Stock	P	500000	$10	Acquired	500000	Indirect

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2019-05-28	Series A Preferred Stock	$	C	1721898	Disposed		Common Stock (1721898)	Indirect
2019-05-28	Series B Preferred Stock	$	C	578447	Disposed		Common Stock (578447)	Indirect
2019-05-28	Series A Preferred Stock	$	C	71745	Disposed		Common Stock (71745)	Indirect
2019-05-28	Series B Preferred Stock	$	C	24101	Disposed		Common Stock (24101)	Indirect

Footnotes

F1: 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.

F2: Each share of Series A Preferred Stock was automatically converted on a 1-for-1 basis into Common Stock immediately prior to the closing of the Issuer's initial public offering.

F3: The shares are held by 5AM Ventures IV, L.P. ("Ventures IV"). 5AM Partners IV, LLC ("Partners IV") is the sole general partner of Ventures IV. Dr. John Diekman, Andrew J. Schwab and Dr. Scott M. Rocklage, are the managing members of Partners IV, and have shared voting and investment power over the shares beneficially owned by Ventures IV. Each of Partners IV, Dr. Diekman, Mr. Schwab, and Dr. Rocklage disclaims beneficial ownership of such shares except to the extent of its or their pecuniary interest therein.

F4: Each share of Series B Preferred Stock was automatically converted on a 1-for-1 basis into Common Stock immediately prior to the closing of the Issuer's initial public offering.

F5: The shares are held by 5AM Co-Investors IV, L.P. ("Co-Investors IV"). Partners IV is the sole general partner of Co-Investors IV. Dr. John Diekman, Andrew J. Schwab and Dr. Scott M. Rocklage, are the managing members of Partners IV, and have shared voting and investment power over the shares beneficially owned by Co-Investors IV. Each of Partners IV, Dr. Diekman, Mr. Schwab, and Dr. Rocklage disclaims beneficial ownership of such shares except to the extent of its or their pecuniary interest therein.

F6: The shares are held by 5AM Opportunities I, L.P. ("Opportunities I"). 5AM Opportunities I (GP), LLC ("Opportunities I GP") is the sole general partner of Opportunities I. Kush Parmar and Andrew J. Schwab are the managing members of Opportunities I GP, and have shared voting and investment power over the shares beneficially owned by Opportunities I. Each of Opportunities I GP and Mr. Schwab disclaims beneficial ownership of such shares except to the extent of its or his pecuniary interest therein.