John Tseng-Chung Lee - Oct 31, 2025 Form 4 Insider Report for MKS INC (MKSI)

Role
President & CEO, Director
Signature
/s/ M. Kathryn Rickards, attorney-in-fact
Stock symbol
MKSI
Transactions as of
Oct 31, 2025
Transactions value $
-$287,851
Form type
4
Date filed
11/4/2025, 04:58 PM
Previous filing
May 12, 2025
SEC
View on sec.gov

Reporting Owners (1)

Name Relationship Address Signature Signature date CIK
Lee John Tseng-Chung President & CEO, Director C/O MKS INC., 2 TECH DRIVE, ANDOVER /s/ M. Kathryn Rickards, attorney-in-fact 2025-11-04 0001414656

Transactions Table

Type Sym Class Transaction Value $ Shares Change % * Price $ Shares After Date Ownership Footnotes
transaction MKSI Common Stock Options Exercise +352 +0.24% 148K Oct 31, 2025 Direct F1
transaction MKSI Common Stock Options Exercise +1.65K +1.12% 149K Oct 31, 2025 Direct F1
transaction MKSI Common Stock Tax liability -$288K -2K -1.34% $143.71 147K Oct 31, 2025 Direct F2

Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)

Type Sym Class Transaction Value $ Shares Change % * Price $ Shares After Date Underlying Class Amount Exercise Price Ownership Footnotes
transaction MKSI Restricted Stock Unit Options Exercise -352 -0.39% 89.8K Oct 31, 2025 Common Stock 352 Direct F1, F3
transaction MKSI Restricted Stock Unit Options Exercise -1.65K -1.84% 88.2K Oct 31, 2025 Common Stock 1.65K Direct F1, F4
* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id Content
F1 Each restricted stock unit (RSU) represents the contingent right to receive one share of common stock of MKS Inc.
F2 Shares used to satisfy FICA taxes.
F3 Portion of 2024 RSU Award accelerated to satisfy FICA taxes.
F4 Portion of 2025 RSU Award accelerated to satisfy FICA taxes.