144 0001256715 XXXXXXXX LIVE 0001049502 MKS Inc. 000-23621 2 Tech Dr Andover MA 01810 9786455500 Gerald Colella 2019 Trust u/a dtd 5/4/2019 Director Common Merrill

100 Federal St, 12th Fl Boston MA 02110

20000 5057995.6 67169474 02/20/2026 Nasdaq Common 02/15/2020 Stock grant MKS Inc. N 2 02/15/2020 Cashless Common 07/02/2020 Stock grant MKS Inc. N 10979 07/02/2020 Cashless Common 05/10/2021 Stock grant MKS Inc. N 1 05/10/2021 Cashless Common 05/09/2022 Stock grant MKS Inc. N 1 05/09/2022 Cashless Common 02/15/2018 Stock grant MKS Inc. N 4269 02/15/2018 Cashless Common 02/15/2019 Stock grant MKS Inc. N 4748 02/15/2019 Cashless Y 02/20/2026 Molly Smith