Masimo

MASI • NASDAQ

Masimo is a medical - instruments & supplies company in the healthcare sector on NASDAQ, led by Catherine Szyman, with a market cap of $7.4B. As of Q3 2025, 103% of shares are held by 346 institutional investors, with BlackRock, Inc. as the largest holder at 19.07%.

Chief Executive OfficerCatherine Szyman

Market Cap$7.4B

Medical - Instruments & Supplies

Healthcare

Employees3.8K

Websitemasimo.com

Country

United States of America

Overview

Overview of institutional ownership in MASI as of Q3 2025 with a market cap of $8.0B

All Institutions

Institutions: 346
Value Held: $8.3B
Shares Held: 56.2M
Avg Position: $23.9M
Median Position: $757.0K

Hedge Funds

Hedge Funds: 44
Value Held: $1.4B
Shares Held: 9.8M
Avg Position: $32.7M
Median Position: $1.5M

Ownership Breakdown

Institutional (non-HF)

85.37%

$6.8B

Hedge Funds

17.97%

$1.4B

Retail & Other

Based on market cap of $8.0B as of Q3 2025. Institutional (non-HF) excludes hedge funds to avoid double counting.

Biggest Investors

Institutions with the largest positions in MASI as of Q3 2025

Institution	Key People	Position Value	Ownership	Owned Since	Total AUM (Long)
B BlackRock, Inc. Institution	-	$1.5B 0.03% of portfolio	19.07% 10.4M shares	≤ Q2 2013 Held for 12y 5m+	$5.67T
FMR LLC Institution	-	$1.2B 0.06% of portfolio	15.12% 8.2M shares	Q4 2017 Held for 7y 11m	$1.92T
VANGUARD GROUP INC Institution	Salim Ramji CEO	$709.7M 0.01% of portfolio	8.85% 4.8M shares	≤ Q2 2013 Held for 12y 5m+	$6.69T
Politan Capital Management LP Hedge Fund•Activist	Quentin George Koffey CIO	$677.2M 61.54% of portfolio	8.45% 4.6M shares	Q3 2022 Held for 3y 2m	$1.1B
MASSACHUSETTS FINANCIAL SERVICES CO /MA/ Long Only Manager	Edward Murray Maloney CEO	$386.6M 0.12% of portfolio	4.82% 2.6M shares	Q3 2023 Held for 2y 2m	$322.72B
T T. Rowe Price Investment Management, Inc. Insurance Manager	John Edward Robison President	$313.8M 0.19% of portfolio	3.91% 2.1M shares	Q4 2022 Held for 2y 11m	$161.58B
Capital Research Global Investors RIA/Wealth	Maria Alejandra Herrera CIO	$273.6M 0.05% of portfolio	3.41% 1.9M shares	Q4 2022 Held for 2y 11m	$532.36B
STATE STREET CORP Institution	Ronald P. O'Hanley CEO	$219.0M 0.01% of portfolio	2.73% 1.5M shares	≤ Q2 2013 Held for 12y 5m+	$2.88T
WESTFIELD CAPITAL MANAGEMENT CO LP Long Only Manager	William Albert Muggia CEO	$209.4M 0.88% of portfolio	2.61% 1.4M shares	Q2 2023 Held for 2y 5m	$23.8B
A Alyeska Investment Group, L.P. Hedge Fund•Multi-Strategy	Anand Christopher Parekh CEO	$203.8M 0.62% of portfolio	2.54% 1.4M shares	Q2 2021 Held for 4y 5m	$33.0B

Net Capital Flow

Institutional buying and selling activity for MASI in Q3 2025

Traded: −$92.5M
Buyers: 163
Sellers: 183
Total Bought: +$630.4M
Total Sold: −$722.9M
Avg Position: $20.2M

Biggest Buyers

Institution	Net Bought	Current Position
S Squarepoint Ops LLC Hedge Fund•Quant	+$80.7M +546.9K shares	$91.6M 620.9K shares
VIKING GLOBAL INVESTORS LP Hedge Fund•Long/Short	+$45.2M +306.0K shares	$158.4M 1.1M shares
GOLDMAN SACHS GROUP INC Institution	+$40.3M +272.9K shares	$109.8M 744.4K shares
A Alyeska Investment Group, L.P. Hedge Fund•Multi-Strategy	+$36.4M +246.6K shares	$203.8M 1.4M shares
WESTFIELD CAPITAL MANAGEMENT CO LP Long Only Manager	+$35.1M +238.0K shares	$209.4M 1.4M shares
BANK OF AMERICA CORP /DE/ Institution	+$31.7M +214.9K shares	$59.8M 405.1K shares
VANGUARD GROUP INC Institution	+$25.4M +171.9K shares	$709.7M 4.8M shares
A ADAGE CAPITAL PARTNERS GP LLC Institution	+$22.1M +150.0K shares	$22.1M 150.0K shares
MASSACHUSETTS FINANCIAL SERVICES CO /MA/ Long Only Manager	+$22.1M +149.6K shares	$386.6M 2.6M shares
Marshall Wace LLP Institution	+$18.7M +126.9K shares	$19.8M 134.1K shares

Biggest Sellers

Institution	Net Sold	Current Position
Holocene Advisors, LP Hedge Fund•Long/Short	−$209.2M −1.2M shares	Sold Off 0 shares
Durable Capital Partners LP Hedge Fund•Long/Short	−$80.2M −543.3K shares	$91.6M 620.6K shares
T T. Rowe Price Investment Management, Inc. Insurance Manager	−$55.1M −373.4K shares	$313.8M 2.1M shares
DIMENSIONAL FUND ADVISORS LP Long Only Manager	−$38.9M −263.6K shares	$38.3M 259.7K shares
Woodline Partners LP Hedge Fund•Long/Short	−$30.7M −182.7K shares	Sold Off 0 shares
Hawk Ridge Management LLC Hedge Fund•Long/Short	−$25.0M −148.7K shares	Sold Off 0 shares
B BlackRock, Inc. Institution	−$21.6M −146.2K shares	$1.5B 10.4M shares
Politan Capital Management LP Hedge Fund•Activist	−$18.7M −126.9K shares	$677.2M 4.6M shares
SCHRODER INVESTMENT MANAGEMENT GROUP RIA/Wealth	−$16.0M −111.9K shares	$48.1M 336.7K shares
Partner Fund Management, L.P. Hedge Fund•Sector	−$15.9M −94.5K shares	Sold Off 0 shares

Entry and Exit Activity

Institutions that initiated new positions or completely exited MASI in Q3 2025

New Positions: 12
New Value: $12.2M
Exited Positions: 64
Exited Value: $368.0M

New Positions

Institution	Position Value
S Swedbank AB Institution	$10.0M 67.5K shares
P Polymer Capital Management LLC Hedge Fund•Multi-Strategy	$867.0K 5.9K shares
D DRW Securities, LLC Institution	$475.6K 3.2K shares
F FIDUCIARY TRUST CO Institution	$300.3K 2.0K shares
1 111 Capital Institution	$245.8K 1.7K shares
Catalytic Wealth RIA, LLC RIA/Wealth	$235.8K 1.6K shares
ISAM Funds Ltd Hedge Fund•Quant	$103.1K 699.0 shares
JPL Wealth Management, LLC RIA/Wealth	$18.6K 126.0 shares
Sontag Advisory, LLC RIA/Wealth	$16.5K 112.0 shares
ZRC WEALTH MANAGEMENT, LLC RIA/Wealth	$1.8K 12.0 shares

Exited Positions

Institution	Previous Position
Holocene Advisors, LP Hedge Fund•Long/Short	$209.2M 1.2M shares
Woodline Partners LP Hedge Fund•Long/Short	$30.7M 182.7K shares
Hawk Ridge Management LLC Hedge Fund•Long/Short	$25.0M 148.7K shares
Partner Fund Management, L.P. Hedge Fund•Sector	$15.9M 94.5K shares
Point72 Ltd RIA/Wealth	$11.6M 68.7K shares
F FIL Ltd Institution	$9.5M 56.3K shares
BANK OF NOVA SCOTIA / Institution	$8.9M 53.1K shares
Cinctive Capital Management LP Hedge Fund•Multi-Strategy	$7.9M 46.8K shares
N NATIXIS Institution	$7.7M 45.6K shares
4D Advisors, LLC Hedge Fund•Long/Short	$7.6M 45.0K shares

Options Activity

Institutions with the largest Call and Put options positions in MASI as of Q3 2025

Call Positions: 4
Call Value: $5.3M
Put Positions: 4
Put Value: $5.4M

Call Positions

Institution	Position Value
SUSQUEHANNA INTERNATIONAL GROUP, LLP Private Equity	$2.9M 198.0 contracts
CITADEL ADVISORS LLC Hedge Fund•Multi-Strategy	$1.6M 108.0 contracts
J JANE STREET GROUP, LLC Institution	$619.7K 42.0 contracts
W WOLVERINE TRADING, LLC Institution	$200.1K 14.0 contracts

Put Positions

Institution	Position Value
SUSQUEHANNA INTERNATIONAL GROUP, LLP Private Equity	$4.5M 308.0 contracts
CITADEL ADVISORS LLC Hedge Fund•Multi-Strategy	$383.6K 26.0 contracts
W WOLVERINE TRADING, LLC Institution	$228.7K 16.0 contracts
J JANE STREET GROUP, LLC Institution	$221.3K 15.0 contracts

Most Committed Institutions

Institutions with MASI as the highest % of their portfolio as of Q3 2025

Institution	Key People	Portfolio Weight	Ownership	Owned Since	Total AUM (Long)
Politan Capital Management LP Hedge Fund•Activist	Quentin George Koffey CIO	61.54% $677.2M	8.45% 4.6M shares	Q3 2022 Held for 3y 2m	$1.1B
BRIDGER MANAGEMENT, LLC Hedge Fund•Long/Short	Matthew P Truax COO	4.11% $7.1M	0.09% 47.8K shares	Q1 2025 Held for 8 months	$171.6M
LOCKERMAN FINANCIAL GROUP, INC. RIA/Wealth	Lisa Lynn Lockerman CCO	2.22% $1.7M	0.02% 11.8K shares	Q4 2021 Held for 3y 11m	$78.3M
Falcon Edge Capital LP Hedge Fund•Multi-Strategy	Richard Matthew Gerson Founder	1.45% $14.3M	0.18% 97.1K shares	Q2 2025 Held for 5 months	$987.3M
Liontrust Investment Partners LLP Long Only Manager	John Stephen Ions CEO	1.42% $100.6M	1.26% 681.9K shares	Q1 2022 Held for 3y 8m	$7.1B
RTW INVESTMENTS, LLC Hedge Fund•Sector	Peter M Fong President	1.25% $100.8M	1.26% 683.3K shares	Q3 2015 Held for 10y 2m	$8.1B
CRAMER ROSENTHAL MCGLYNN LLC Long Only Manager	Brian Michael Harvey CEO	1.09% $16.9M	0.21% 114.6K shares	Q2 2024 Held for 1y 5m	$1.6B
W WILSON ASSET MANAGEMENT PTY LTD Institution	-	0.99% $4.0M	0.05% 27.2K shares	Q2 2025 Held for 5 months	$404.2M
Westmount Partners, LLC Fund of Funds	James Edgar Berliner Chairman	0.95% $3.7M	0.05% 25.9K shares	Q4 2022 Held for 2y 11m	$387.2M
B Birchview Capital, LP Hedge Fund•Value	Matthew William Strobeck CIO	0.94% $1.2M	0.02% 8.3K shares	Q4 2014 Held for 10y 11m	$130.3M

Hedge Fund Spotlight

Discover hedge funds investing in MASI

VOLORIDGE INVESTMENT MANAGEMENT, LLC

Hedge Fund • Multi-Strategy

Portfolio ManagerDavid Spiel Vogel

Portfolio Value: $29.8B
Positions: 1,153
Last Reported: Q3 2025

Sector Allocation

Position in Masimo

Market Value: $422.4K
Shares Held: 2.9K
Portfolio Weight: 0.00%
Owned Since: 2025-Q3

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