York Charles N II 4

What Happened
Charles N. York II, Day One Biopharmaceuticals' COO and CFO, disposed of a total of 1,832,817 shares (including shares delivered on derivative awards) on April 23, 2026 in connection with the company’s merger with Servier. Under the merger, each share was purchased for $21.50 per share (the Offer Price), so the aggregate cash consideration for these shares was approximately $39.4 million before applicable withholding taxes. The dispositions were "to the issuer" (D) as the merger consideration was paid in cash; many of the shares converted were derivative awards (options/RSUs) that were cashed out.

Key Details

• Transaction date: April 23, 2026 (filing date: April 23, 2026 — timely).
• Price: $21.50 per share (Offer Price per Merger Agreement, Footnote F2).
• Total shares disposed: 1,832,817 shares.
  • Direct common shares: 312,025 shares.
  • Derivative-based shares (options/RSUs converted to cash): 1,520,792 shares.
• Approximate gross proceeds: ~$39.4 million (before applicable withholding taxes).
• Footnotes of note:
  • F1/F2: The dispositions were part of the Merger with Servier; all issued and outstanding shares were purchased or converted into the Offer Price.
  • F4: Outstanding unvested stock options and RSUs became fully vested immediately prior to the merger and were canceled/converted into the right to receive cash.
  • F10–F13: RSUs represented contingent rights to one share each and, under the terms, were treated in the merger as described above.
• Shares owned after transaction: The filing indicates the reporting person’s equity awards and shares were converted/cashed out in the merger (i.e., no remaining common shares from the canceled awards).
• Taxes/withholding: Merger consideration was paid net of applicable withholding taxes per the merger terms.

Context

• These are merger-related cash payouts (dispositions to the issuer), not open-market sales. Dispositions labeled as derivative reflect options or RSUs that were cashed out per the Merger Agreement rather than exercised and held.
• This transaction is procedural in connection with the change of control; it does not necessarily indicate a voluntary “sell” decision by the insider in the same sense as an open-market sale.