CURTIS GEORGE L 4

What Happened

• George L. Curtis, Executive Vice President of Clean Harbors (CLH), disposed of a total of 1,378 shares on 2026-03-13. Of those, 350 shares were withheld to cover tax liability at $288.93 per share (cash value approximately $101,126). An additional 1,028 restricted shares were forfeited and reported with $0 proceeds because the company did not meet the performance targets under its Long Term Equity Incentive Program.
• These were disposals/forfeitures and tax-withholding actions tied to equity vesting/awards, not open-market purchases.

Key Details

• Transaction dates and prices: 2026-03-13 — 350 shares withheld at $288.93 (total ~$101,126); 1,028 shares forfeited to issuer at $0.00.
• Shares owned after transaction: not specified in the filing (check the original Form 4 for post-transaction holdings).
• Notable footnotes: F1 = tax withholding of shares incident to vesting; F2 = restricted shares forfeited due to failure to meet LTIP performance targets; F3 = filing notes inclusion of 11 shares acquired under the Clean Harbors Employee Stock Purchase Plan.
• Filing date: Form 4 was filed 2026-03-17 reporting transactions dated 2026-03-13 — consult the filing for timeliness details.

Context

• Tax-withholding by surrendering shares is a common, administrative consequence of vesting (effectively a cashless tax payment), not an open-market sale signal.
• Forfeiture of performance shares reflects unmet performance conditions under the LTIP and is not a market sale — it reduces outstanding shares held by the insider but does not generate proceeds.