D1 Capital Partners L.P. Discloses 2.5% Stake in Clean Harbors Inc. (CLH) via Schedule 13G/A

D1 Capital Partners L.P. and Daniel Sundheim filed a Schedule 13G/A on May 15, 2026, disclosing a 2.5% ownership stake in Clean Harbors Inc. (CLH). The filing indicates that the reporting persons beneficially own 1,338,281 shares of common stock as of the event date of March 31, 2026. This represents an increase from a previous 0.0% position, though the total ownership remains below the 5% threshold typically requiring active disclosure, leading to the check of Item 5 regarding ownership of 5% or less. D1 Capital Partners L.P. serves as the investment manager for private investment vehicles, including D1 Capital Partners Master LP, which holds the shares. Daniel Sundheim, who indirectly controls the investment manager, is also named as a reporting person. The shares were acquired in the ordinary course of business and not for the purpose of influencing or changing the control of the issuer. The percentage calculation is based on approximately 52.9 million shares outstanding.