<div id="readability-page-1"><div><p><span>Merendino Lauren, Officer of Day One Biopharmaceuticals Inc [DAWN], filed a Form 144 on November 17, 2025 with the Securities and Exchange Commission proposing to sell restricted securities:</span></p><div><table><tbody><tr><td><span>Approximate Date Of Sale</span></td><td><span>11/17/25</span></td></tr><tr><td><span>Shares</span></td><td><span>3,726</span></td></tr><tr><td><span>Broker</span></td><td><span>Morgan Stanley Smith Barney LLC</span></td></tr></tbody></table></div><p><span>Prior to the sale of restricted stock, owners must file a Form 144 with the SEC.  Upon submission of the filing to the SEC the owner is permitted to sell the shares, or any fraction thereof, within 90 days.</span></p><p><span>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.</span></p><p><span>Founded in 1970, The Washington Service provides securities professionals with financial, economic and public policy research and data.</span></p><span> </span></div></div>

DAWN

<p>Officer Lauren Merendino of Day One Biopharmaceuticals Inc filed a Form 144 with the SEC to sell 3,726 shares on November 17, 2025. The sale will be brokered by Morgan Stanley Smith Barney LLC. Form 144 is required for selling restricted stock, allowing sales within 90 days of filing. The Washington Service offers insider trading analysis and data services.</p>

Officer Merendino Files To Sell 3,726 Of Day One Biopharmaceuticals Inc [DAWN]