ENTEGRIS INC

On December 4, 2025, Bertrand Loy, our Executive Chair, entered into a Rule 10b5-1 trading plan intended to satisfy the affirmative defense conditions of Rule 10b5-1(c) under the Exchange Act. Mr. Loy’s plan provides for the sale of up to 100,000 shares of the Company’s common stock. The plan expires on November 6, 2026, or upon the earlier completion of all authorized transactions under the plan.

During the quarter ended March 31, 2025, each of (i) Bertrand Loy, our former Chief Executive Officer and the current Executive Chair, (ii) Clint Haris, Senior Vice President and President, Advanced Purity Solutions, and (iii) Mr. James O’Neill, our former Chief Technology Officer, entered into a Rule 10b5-1 Plan. The details of these plans are set forth below.

On February 10, 2025, Mr. Loy entered into a Rule 10b5-1 trading plan intended to satisfy the affirmative defense conditions of Rule 10b5-1(c) under the Exchange Act. Mr. Loy’s plan provides for the sale of up to 194,192 shares of the Company’s common stock. The plan expires on February 19, 2027, or upon the earlier completion of all authorized transactions under the plan.

On February 10, 2025, Mr. Haris entered into a Rule 10b5-1 trading plan intended to satisfy the affirmative defense conditions of Rule 10b5-1(c) under the Exchange Act. Mr. Haris’ plan provides for the sale of up to 15,287 shares of the Company’s common stock. The plan expires on February 12, 2026, or upon the earlier completion of all authorized transactions under the plan.

On February 14, 2025, Mr. O’Neill entered into a new Rule 10b5-1 Plan intended to satisfy the affirmative defense conditions of Rule 10b5-1(c) under the Exchange Act. The plan provides for the sale of up to 6,250 shares of the Company’s common stock. The plan expires on February 13, 2026, or upon the earlier completion of all authorized transactions under the plan.

These plans were inadvertently omitted from the Company’s prior disclosures due to an administrative oversight. The Company has updated its disclosure controls and procedures to ensure timely reporting of such arrangements going forward.