John Edward Williams - 17 Apr 2026 Form 4 Insider Report for MKS INC (MKSI)

Reporting relationship: EVP & GM, PSD
Issuer ticker: MKSI
Reported as of: 17 Apr 2026
Net transaction value: $0
SEC form: 4
Accepted by SEC: 20 Apr 2026, 11:31:19 UTC
Prior SEC filing: 23 Feb 2026
Next SEC filing: 04 Aug 2026
Source filing: View source filing
Reporting owner signature: /s/ James Kruger, attorney-in-fact

Key filing fact

John Edward Williams filed Form 4 for MKS INC (MKSI) on 20 Apr 2026.

Key facts

This page summarizes John Edward Williams's Form 4 filing for MKS INC (MKSI).
3 reported transactions and 1 derivative row are listed below.
Accepted by SEC: 20 Apr 2026, 11:31.

Change

Previous filing in this sequence was filed on 23 Feb 2026.
Current net transaction value: $0.

Research use

This tells you what this filing adds before you inspect full transaction and derivative tables.
You can trace every row back to the original SEC filing document.

Evidence

Filed on Form 4

Ownership activity is grounded in SEC Form 4 disclosures.

View source filing

Reporting Owners (1)

CIK 0001710173 Primary reporting owner

Williams John Edward

Relationship: EVP & GM, PSD
Address: C/O MKS INC., 2 TECH DRIVE, ANDOVER
Signature: /s/ James Kruger, attorney-in-fact
Signature date: 20 Apr 2026

Reported non-derivative transactions

Shares, units, or other non-derivative securities reported in this filing.

MKSI transaction

Common Stock

Options Exercise

Transaction value
Shares: +1,741
Change %: +48%
Price
Shares after: 5,381
Date: 17 Apr 2026
Ownership: Direct
Footnotes: F1

MKSI transaction

Common Stock

Tax liability

Transaction value
Shares: -826
Change %: -15%
Price: $269.89^*
Shares after: 4,555
Date: 17 Apr 2026
Ownership: Direct
Footnotes: F2

Reported derivative securities

Options, warrants, convertible securities, or similar derivative positions disclosed in the filing.

MKSI transaction Derivative

Restricted Stock Unit

Options Exercise

Transaction value
Shares: -1,741
Change %: -20%
Price
Shares after: 6,812
Date: 17 Apr 2026
Ownership: Direct
Underlying class: Common Stock
Underlying amount: 1,741
Exercise price
Footnotes: F1, F3

^* marks a reported price that did not pass the local price check.

Additional SEC filing notes

Filing notes and footnotes

Explanation of responses 3 footnotes

Footnote F1

Each restricted stock unit (RSU) represents the contingent right to receive one share of common stock of MKS Inc.

Footnote F2

These shares were withheld by MKS Inc. to satisfy the tax withholding obligations triggered by the vesting of RSUs and do not represent a discretionary trade by the reporting person.

Footnote F3

These RSUs vest in two equal annual installments commencing on April 17, 2025, provided that if, in any vesting year, April 17th is not a business day, such vesting shall occur on the next business day.