Kathleen Flaherty Burke - Oct 31, 2025 Form 4 Insider Report for MKS INC (MKSI)

Role
EVP, GC & Secretary
Signature
/s/ M. Kathryn Rickards, attorney-in-fact
Stock symbol
MKSI
Transactions as of
Oct 31, 2025
Transactions value $
-$111,663
Form type
4
Date filed
11/4/2025, 05:01 PM
Previous filing
Feb 19, 2025
SEC
View on sec.gov

Reporting Owners (1)

Name Relationship Address Signature Signature date CIK
Burke Kathleen Flaherty EVP, GC & Secretary C/O MKS INC., 2 TECH DRIVE, ANDOVER /s/ M. Kathryn Rickards, attorney-in-fact 2025-11-04 0001775435

Transactions Table

Type Sym Class Transaction Value $ Shares Change % * Price $ Shares After Date Ownership Footnotes
transaction MKSI Common Stock Options Exercise +158 +0.31% 51.2K Oct 31, 2025 Direct F1
transaction MKSI Common Stock Options Exercise +52 +0.1% 51.3K Oct 31, 2025 Direct F1
transaction MKSI Common Stock Options Exercise +82 +0.16% 51.4K Oct 31, 2025 Direct F1
transaction MKSI Common Stock Options Exercise +144 +0.28% 51.5K Oct 31, 2025 Direct F1
transaction MKSI Common Stock Options Exercise +341 +0.66% 51.9K Oct 31, 2025 Direct F1
transaction MKSI Common Stock Tax liability -$112K -777 -1.5% $143.71 51.1K 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 -158 -0.89% 17.6K Oct 31, 2025 Common Stock 158 Direct F1, F3
transaction MKSI Restricted Stock Unit Options Exercise -52 -0.3% 17.6K Oct 31, 2025 Common Stock 52 Direct F1, F4
transaction MKSI Restricted Stock Unit Options Exercise -82 -0.47% 17.5K Oct 31, 2025 Common Stock 82 Direct F1, F3
transaction MKSI Restricted Stock Unit Options Exercise -144 -0.82% 17.3K Oct 31, 2025 Common Stock 144 Direct F1, F4
transaction MKSI Restricted Stock Unit Options Exercise -341 -1.97% 17K Oct 31, 2025 Common Stock 341 Direct F1, F5
* 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 2023 RSU Award accelerated to satisfy FICA taxes.
F4 Portion of 2024 RSU Award accelerated to satisfy FICA taxes.
F5 Portion of 2025 RSU Award accelerated to satisfy FICA taxes.