Form 4 Filing for MKS Inc.

This filing details transactions by John Edward Williams, EVP & GM, PSD of MKS Inc. On April 17, 2026, Mr. Williams acquired 1740.714 shares of Common Stock through the vesting of Restricted Stock Units (RSUs). Concurrently, 825.969 shares were disposed of to cover tax withholding obligations related to the RSU vesting. The RSUs vest in two equal annual installments starting April 17, 2025. Following these transactions, Mr. Williams holds 5380.813 shares directly and 6812.003 shares indirectly through RSUs.