MASIMO CORP (MASI) Institutional Ownership Changes & 13F Activity

MASIMO CORP (MASI). Institutional ownership data tracks hedge funds, asset managers, and other institutional investors based on recent SEC Form 13F filings (Q1 2026). This page analyzes institutional buying and selling activity, new holdings, and sold-out positions in the latest reporting period. Notable filers include Fmr Llc, Pentwater Capital Management Lp, Barclays Plc, Hbk Investments L P, and Millennium Management Llc.

InstitutionTypeChange in sharesChange Position %SharesReported stock balancePortfolio quarterFiling date
Neuberger Berman Group LlcBuy+398,303+7956.5%403,309$71.74MQ1 2026Oct 27, 2026
Op Asset Management LtdSell-8,207-100.0%0$0.00Q1 2026Sep 28, 2026
M&T Bank CorpSell-6,069-63.3%3,516$625.83KQ1 2026Sep 04, 2026
Ensign Peak Advisors, IncSell-2,711-100.0%0$0.00Q1 2026Aug 18, 2026
O'Connor Alternative Investments LlcBuy+412,903—412,903$73.44MQ1 2026Aug 14, 2026
Taconic Capital Advisors LpBuy+30,000—30,000$5.34MQ1 2026Aug 14, 2026
Oxford Asset Management LlpBuy+12,202—12,202$2.17MQ1 2026Aug 14, 2026
Brighton Jones LlcBuy+5,281—5,281$939.28KQ1 2026Aug 07, 2026
Verus Capital Partners, LlcSell-3,651-100.0%0$0.00Q1 2026Jul 09, 2026
Wells Fargo & Company/MnSell-7,360-39.4%11,337$2.02MQ1 2026Jul 08, 2026
Western Wealth Management, LlcBuy+250—250$44.47KQ1 2026May 19, 2026
AmundiBuy+199,283+454.4%243,143$43.25MQ1 2026May 18, 2026
Bank Of America CorpSell-52,699-18.5%232,003$41.27MQ1 2026May 18, 2026
California State Teachers Retirement SystemBuy+9,464+21.6%53,287$9.48MQ1 2026May 18, 2026
South Dakota Investment CouncilSell-3,700-17.4%17,568$3.13MQ1 2026May 18, 2026
Bull Harbor Capital LlcBuy+2,151—2,151$382.60KQ1 2026May 18, 2026
Fmr LlcSell-6,413,341-81.6%1,450,823$258.06MQ1 2026May 15, 2026
Pentwater Capital Management LpBuy+3,176,000—3,176,000$564.92MQ1 2026May 15, 2026
Barclays PlcBuy+2,685,627+4602.0%2,743,985$488.07MQ1 2026May 15, 2026
Hbk Investments L PBuy+2,576,109—2,576,109$458.21MQ1 2026May 15, 2026
Millennium Management LlcBuy+800,888+426.1%988,853$175.89MQ1 2026May 15, 2026
Balyasny Asset Management L.P.Buy+770,986—770,986$137.14MQ1 2026May 15, 2026
Fil LtdBuy+482,000—482,000$85.73MQ1 2026May 15, 2026
Aqr Arbitrage LlcBuy+416,956—416,956$73.87MQ1 2026May 15, 2026
Alliancebernstein L.P.Buy+401,131+739.8%455,354$59.22MQ1 2026May 15, 2026
Goldman Sachs Group IncBuy+347,494+54.6%984,192$175.06MQ1 2026May 15, 2026
Fort Baker Capital Management LpBuy+312,720—312,720$55.62MQ1 2026May 15, 2026
Nexpoint Asset Management, L.P.Buy+310,130—310,130$55.16MQ1 2026May 15, 2026
Capitolis Liquid Global Markets LlcBuy+309,102—309,102$54.98MQ1 2026May 15, 2026
Aqr Capital Management LlcSell-259,360-23.8%831,966$147.40MQ1 2026May 15, 2026
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Frequently asked questions about MASI activity

  • Which institutional owners are buying MASI?

    Institutional owners buying MASI 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 MASI activity?

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

  • Is institutional interest in MASI increasing?

    Institutional interest in MASI 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.