As previously announced, on April 1, 2024, Seth H. Bagshaw retired as Chief Financial Officer of MKS Instruments, Inc. Mr. Bagshaw will remain employed in the role of special advisor to the company until May 1, 2024. Following Mr. Bagshaw's retirement, on April 1, 2024, John T.C. Lee, President and Chief Executive Officer of the company, assumed the role of principal financial officer of the company on an interim basis while the company continues its search for Mr. Bagshaw's successor.