PETERS WILLIAM J 4

What Happened
William J. Peters, Amphastar Pharmaceuticals' CFO, EVP & Treasurer and a company director, had 1,973 restricted stock units (RSU) shares withheld to satisfy his tax liability upon vesting. The withholding is reported as a disposition (code F) at $18.18 per share, for a total value of roughly $35,869. This is an administrative tax-withholding action tied to RSU vesting—not an open-market sale or purchase.

Key Details

• Transaction date: 2026-03-15; Filing date (Form 4): 2026-03-17 (filing appears timely).
• Shares withheld/disposed: 1,973 at $18.18 per share; total value ≈ $35,869.
• Shares owned after transaction: not specified in the filing.
• Footnote: F1 — shares were withheld to cover the reporting person’s tax liability in connection with RSU vesting.
• Transaction code: F (tax withholding related to RSU vesting), not a market sale (S) or purchase (P).

Context
Tax-withholding by withholding or surrendering vested RSUs is a common, routine administrative step and does not necessarily signal insider sentiment about the stock. For retail investors, purchases are generally more informative than withholding or routine dispositions like this one.