Question 1

Does Westfield Capital Management own MKSI stock?

Accepted Answer

Yes. As of its Q2 2026 13F, Westfield Capital Management holds 928,617 shares of MKSI (MKS), worth $413M.

Question 2

How many shares of MKSI does Westfield Capital Management own?

Accepted Answer

As of its Q2 2026 13F, Westfield Capital Management holds 928,617 shares of MKSI (MKS).

Question 3

What is Westfield Capital Management's MKSI position worth?

Accepted Answer

As of its Q2 2026 13F, Westfield Capital Management's MKSI position is worth $413M.

Question 4

Is Westfield Capital Management buying or selling MKSI?

Accepted Answer

In Q2 2026, Westfield Capital Management reduced its MKSI position by 118,146 shares (-11.3%).

Question 5

When did Westfield Capital Management first buy MKSI?

Accepted Answer

Westfield Capital Management already held MKSI in its Q4 2018 13F, the earliest on record, and has listed it in 21 quarterly 13F filings.

Quarter	Action	Shares	Change	Value	Weight	Price	Conviction
2026-Q2 Latest	Decreased	928,617	-11.3%	$413M	1.3%	$444.39	0
2026-Q1	Increased	1M	+24.6%	$240.6M	1.0%	$229.42	59
2025-Q4	Increased	839,773	+159.7%	$134.2M	0.6%	$159.38	69
2025-Q3	New	323,364	-	$40M	0.2%	$123.25	48
2024-Q4	Exited	0	-100.0%	$0	0.0%	$103.24	0
2024-Q3	Unchanged	24,100	0.0%	$2.6M	0.0%	$107.31	0

MKSIShowing 6 of 24 quarters

MKSI
Showing 6 of 24 quarters