MCKIM ALAN S 4

What Happened
Alan S. McKim, Executive Chair, CTO and Director of Clean Harbors (CLH), had 1,265 shares withheld to satisfy tax withholding obligations tied to vested securities. The shares were valued at $288.93 each for a total of $365,496 on March 13, 2026. This was a withholding to cover taxes—not an open-market sale.

Key Details

• Transaction date and price: March 13, 2026 — 1,265 shares withheld at $288.93 per share (total ~$365,496).
• Transaction code: F (withholding/tax payment incident to vesting).
• Footnote: F1 — withholding of securities to pay tax liability in connection with vesting under Rule 16b-3.
• Filing date: March 17, 2026 — filed within the typical two business‑day Form 4 deadline (timely).
• Shares owned after transaction: Not specified in the provided filing excerpt.

Context
Tax-withholding transactions (code F) are routine administrative actions where the company retains shares that would otherwise be delivered to the insider to cover payroll/tax obligations on vested awards. They are not the same as an open-market sale and generally do not signal a change in the insider’s market view.