Sec Form 3 Filing - 5AM Ventures IV, L.P. @ IDEAYA Biosciences, Inc. - 2019-05-22

FORM 3 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person 5AM Ventures IV, L.P. 2. Issuer Name and Ticker or Trading Symbol IDEAYA Biosciences, Inc. [ IDYA] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director X __ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) C/O 5AM VENTURES, 501 SECOND STREET, SUITE 350 3. Date of Earliest Transaction (MM/DD/YY) 05/22/2019 (Street) SAN FRANCISCO, CA94107 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) _____ Form filed by One Reporting Person __ X __ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Common Stock 304,200 ( 1 ) I See footnotes ( 2 ) Common Stock 12,675 ( 1 ) I See footnotes ( 3 )

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned ( e.g. , puts, calls, warrants, options, convertible securities) 1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5) 6. Date Exercisable and Expiration Date (MM/DD/YY) 7. Title and Amount of Underlying Securities (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4) Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares Series A Preferred Stock ( 4 ) ( 4 ) ( 4 ) Common Stock 1,721,898 ( 1 ) ( 4 ) I See footnotes ( 2 ) Series A Preferred Stock ( 4 ) ( 4 ) ( 4 ) Common Stock 71,745 ( 1 ) ( 4 ) I See footnotes ( 3 ) Series B Preferred Stock ( 5 ) ( 5 ) ( 5 ) Common Stock 578,447 ( 1 ) ( 5 ) I See footnotes ( 2 ) Series B Preferred Stock ( 5 ) ( 5 ) ( 5 ) Common Stock 24,101 ( 1 ) ( 5 ) I See footnotes ( 3 )

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other 5AM Ventures IV, L.P. C/O 5AM VENTURES 501 SECOND STREET, SUITE 350 SAN FRANCISCO, CA94107 X 5AM Co-Investors IV, L.P. 501 SECOND STREET, SUITE 350 SAN FRANCISCO, CA94107 X 5AM Partners IV, LLC 2200 SAND HILL ROAD, SUITE 110 MENLO PARK, CA94025 X ROCKLAGE SCOTT M C/O 5AM VENTURES 501 SECOND STREET, SUITE 350 SAN FRANCISCO, CA94107 X Schwab Andrew J. C/O 5AM VENTURES 501 SECOND STREET, SUITE 350 SAN FRANCISCO, CA94107 X Signatures /s/ 5AM VENTURES IV, L.P., By: 5AM Partners IV, LLC, its General Partner 05/22/2019 Signature of Reporting Person Date /s/ 5AM CO-INVESTORS IV, L.P., By: 5AM Partners IV, LLC, its General Partner 05/22/2019 Signature of Reporting Person Date /s/ 5AM PARTNERS IV, LLC 05/22/2019 Signature of Reporting Person Date /s/ Scott M. Rocklage 05/22/2019 Signature of Reporting Person Date /s/ Andrew J. Schwab 05/22/2019 Signature of Reporting Person Date

Explanation of Responses:

( 1 )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. ( 2 )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. ( 3 )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. ( 4 )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. ( 5 )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.

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).

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