<div id="readability-page-1"><div>York Charles N II Chief Operating Officer of Day One Biopharmaceuticals Inc [DAWN] filed a Form 4 on November 18, 2025 with the Securities and Exchange Commission disclosing the following changes in ownership:<div><table><tbody><tr><th>Date</th><th>Transaction</th><th>Shares</th><th>Price</th><th>Value</th></tr><tr><td>11/15/25</td><td>Exercise</td><td>16,875</td><td>$0.00</td><td>N/A</td></tr><tr><td>11/17/25</td><td>Surrender(1)</td><td>4,062</td><td>$8.91</td><td>$36,212</td></tr></tbody></table></div>Ending Holdings: 294,715 - Direct<ul><li>(1)</li><li>Surrender of shares back to company to pay option exercise cost and/or resulting tax liability.</li></ul>For a free trial, or to learn more about our insider trading analysis and data services, please visit http://www.washingtonservice.com or contact us at (301) 913-5100 or send an email to info@washingtonservice.com.Founded in 1970, The Washington Service provides securities professionals with financial, economic and public policy research and data. </div></div>

DAWN

York Charles N II, COO of Day One Biopharmaceuticals Inc, acquired 12,813 shares of the company. He filed a Form 4 with the SEC on November 18, 2025, detailing changes in ownership, including exercising 16,875 shares and surrendering 4,062 shares to cover option exercise costs and tax liabilities. His ending holdings are 294,715 shares directly.

COO York II Acquires 12,813 Of Day One Biopharmaceuticals Inc [DAWN]