MKS INSTRUMENTS INC (MKSI) Institutional Ownership Changes & 13F Activity

MKS INSTRUMENTS INC (MKSI) institutional ownership data tracks hedge funds, asset managers, and other institutional investors based on recent SEC 13F filings (Q1 2026). This page analyzes institutional buying and selling activity, new holdings, and sold-out positions among tracked filers. Notable filers include Renaissance Technologies LLC, Sequoia Financial Advisors, First Eagle U.S. Value, Hancock Classic Value, and Torray Fund.

Portfolio quarterNameTypeQuantityRemainingReported stock balance
Q3 2021Torray FundBuy1189,637$1,454
Q2 2021Torray FundSell-1449,519$1,694
Q1 2021Torray FundSell-3449,663$1,792
Q4 2020Renaissance Technologies LLCSell-117,20064,452$9,697
Q4 2020Torray FundBuy12610,007$1,506
Q3 2020Renaissance Technologies LLCSell-75,368181,652$19,842
Q3 2020Torray FundBuy349,881$1,079
Q2 2020Torray FundBuy1139,847$1,115
Q1 2020Renaissance Technologies LLCSell-438,263257,020$20,934
Q1 2020Torray FundBuy5229,734$793
Q4 2019Renaissance Technologies LLCSell-438,586695,283$76,488
Q4 2019Torray FundBuy2,2389,212$1,013
Q3 2019Renaissance Technologies LLCSell-463,8831,133,869$104,633
Q3 2019Torray FundBuy336,974$644
Q2 2019Renaissance Technologies LLCSell-234,7481,597,752$124,449
Q2 2019Torray FundSell-7326,941$541
Q1 2019Renaissance Technologies LLCSell-298,4521,832,500$170,514
Q1 2019Torray FundBuy4187,673$714
Q4 2018Renaissance Technologies LLCBuy228,5802,130,952$137,681
Q4 2018Torray FundSell-887,255$469
Q3 2018Renaissance Technologies LLCBuy893,5721,902,372$152,475
Q3 2018Torray FundBuy2377,343$589
Q2 2018Torray FundBuy7,1067,106$680
Q1 2018Renaissance Technologies LLCBuy323,5001,008,800$116,668
Q4 2017Renaissance Technologies LLCBuy92,048685,300$64,761
Q3 2017Renaissance Technologies LLCBuy120,400593,252$56,033
Q2 2017Renaissance Technologies LLCBuy399,500472,852$31,823
Q1 2016Renaissance Technologies LLCBuy43,89473,352$2,762
Q3 2015Renaissance Technologies LLCBuy1,40629,458$988
Q2 2015Renaissance Technologies LLCSell-118,80028,052$1,064

Frequently asked questions about MKSI activity

  • Which institutional owners are buying MKSI?

    Institutional owners buying MKSI include investors who have either initiated new positions or increased their existing holdings based on recent SEC 13F filings. The activity table above highlights which funds added shares in the latest reporting periods and how their positions changed over time.

  • What does "buy" mean in MKSI activity?

    "Buy" means an investor increased their reported position in MKSI compared to the prior reporting period. This reflects growing exposure to MKS INSTRUMENTS INC (MKSI) rather than necessarily a brand-new position (though new positions also appear as buys when prior quantity was zero).

  • Is institutional interest in MKSI increasing?

    Institutional interest in MKSI can be assessed by comparing the number of tracked funds adding or increasing positions versus those trimming or exiting across the periods shown. A higher number of additions typically signals increasing participation among large filers, but it should be read alongside position sizes and the full table.

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