Yujiro S. Hata - 06 Oct 2026 Form 4 Insider Report for IDEAYA Biosciences, Inc. (IDYA)

Reporting relationship: President and CEO, Director
Issuer ticker: IDYA
Reported as of: 06 Oct 2026
Net transaction value: -$985,397
SEC form: 4
Accepted by SEC: 08 Oct 2026, 19:03:44 UTC
Prior SEC filing: 13 Mar 2026
Source filing: View source filing
Reporting owner signature: /s/ Andres Ruiz Briseno, as Attorney-in-Fact for Yujiro Hata

Filing notes and source

Key filing fact

Yujiro S. Hata filed Form 4 for IDEAYA Biosciences, Inc. (IDYA) on 08 Oct 2026.

Key facts

This page summarizes Yujiro S. Hata's Form 4 filing for IDEAYA Biosciences, Inc. (IDYA).
4 reported transactions and 1 derivative row are listed below.
Accepted by SEC: 08 Oct 2026, 19:03.

Change

Previous filing in this sequence was filed on 13 Mar 2026.
Current net transaction value: -$985,397.

Research use

This tells you what this filing adds before you inspect full transaction and derivative tables.
You can trace every row back to the original SEC filing document.

Evidence

Filed on Form 4

Ownership activity is grounded in SEC Form 4 disclosures.

View source filing

Reporting Owners (1)

CIK 0001649119 Primary reporting owner

Hata Yujiro S

Relationship: President and CEO, Director
Address: C/O IDEAYA BIOSCIENCES, INC., 5000 SHORELINE COURT, SUITE 300, SOUTH SAN FRANCISCO
Signature: /s/ Andres Ruiz Briseno, as Attorney-in-Fact for Yujiro Hata
Signature date: 08 Oct 2026

Reported non-derivative transactions

Shares, units, or other non-derivative securities reported in this filing.

IDYA transaction

Common Stock

Options Exercise

Transaction value
Shares: +26,338
Change %: +3.8%
Price: $4.31^*
Shares after: 717,033
Date: 06 Oct 2026
Ownership: Direct

IDYA transaction

Common Stock

Sale

Transaction value: -$954,787
Shares: -25,538
Change %: -3.6%
Price: $37.39
Shares after: 691,495
Date: 06 Oct 2026
Ownership: Direct
Footnotes: F1, F2

IDYA transaction

Common Stock

Sale

Transaction value: -$30,610
Shares: -800
Change %: -0.12%
Price: $38.26
Shares after: 690,695
Date: 06 Oct 2026
Ownership: Direct
Footnotes: F1, F3

Reported derivative securities

Options, warrants, convertible securities, or similar derivative positions disclosed in the filing.

IDYA transaction Derivative

Stock Option (right to buy)

Options Exercise

Transaction value
Shares: -26,338
Change %: -53%
Price: $0.000000^*
Shares after: 23,116
Date: 06 Oct 2026
Ownership: Direct
Underlying class: Common Stock
Underlying amount: 26,338
Exercise price: $4.31
Footnotes: F4

^* marks a reported price that did not pass the local price check.

Additional SEC filing notes

Filing notes and footnotes

Rule 10b5-1 trading plan

These transactions were reported as open-market trades under a Rule 10b5-1 plan. The plan lets an insider set trading instructions in advance, which can reduce the risk of trading while in possession of material nonpublic information.

Original filing language: transaction made pursuant to a contract, instruction, or written plan intended to satisfy Rule 10b5-1(c).

Explanation of responses 4 footnotes

Footnote F1

The transactions reported herein were effected pursuant to the Reporting Person's Rule 10b5-1 trading plan, adopted on July 7, 2026, in which the majority of the shares acquired upon the exercise of stock options were granted to the Reporting Person prior to the Issuer's initial public offering and are approaching their expiration date.

Footnote F2

This transaction was executed in multiple trades in prices ranging from $37.00 to $37.98, 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.

Footnote F3

This transaction was executed in multiple trades in prices ranging from $38.23 to $38.34, 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.

Footnote F4

The shares subject to the option are fully vested and exercisable.