Masimo Ownership | Who Owns Masimo?

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Masimo Ownership Summary

Masimo is owned by 105.15% institutional investors, 5.97% insiders. Blackrock funding, inc. /de is the largest institutional shareholder, holding 19.46% of MASI shares. MFS Mid Cap Growth Equity is the top mutual fund, with 3.09% of its assets in Masimo shares.

MASI Ownership Benchmark

Type	Name	% Inst	% Insiders	% Retail
Stock	Masimo	105.15%	5.97%	-11.12%
Sector	Healthcare Stocks	488.17%	11.08%	-399.26%
Industry	Medical Instruments & Supplies Stocks	56.90%	14.82%	28.28%

Institutional Shareholders

Top Institutional Shareholders by Total Shares

Holder	Shares	% Holding	Value
Blackrock funding, inc. /de	10.51M	19.46%	$1.77B
Blackrock	9.35M	17.64%	$1.18B
Fmr	8.10M	15.16%	$1.34B
Politan capital management lp	4.72M	8.73%	$793.42M
Vanguard group	4.59M	8.59%	$758.18M
T. rowe price investment management	2.50M	4.63%	$420.57M
Massachusetts financial services co /ma/	2.47M	4.57%	$415.57M
Capital research global investors	1.86M	3.44%	$312.16M
State street	1.43M	2.70%	$179.92M
Holocene advisors, lp	1.24M	2.30%	$209.20M

Top Institutional Shareholders by % of Total Assets

Holder	Shares	% Assets	Value
Ace management global	47.69K	100.00%	$7.88M
Politan capital management lp	4.72M	56.98%	$793.42M
Ensemble capital management	407.10K	3.99%	$51.27M
Bridger management	33.64K	3.34%	$5.66M
Lockerman financial group	13.10K	2.97%	$2.20M
Pura vida investments	25.00K	1.99%	$3.15M
Liontrust investment partners llp	792.93K	1.90%	$131.07M
Alpha wave global, lp	102.07K	1.85%	$17.17M
Rtw investments, lp	683.29K	1.64%	$114.94M
Durable capital partners lp	1.16M	1.48%	$195.79M

Top Buyers

Holder	Shares	% Assets	Change
Blackrock	9.35M	0.03%	1.47M
Fmr	8.10M	0.08%	1.34M
Alliancebernstein	947.39K	0.05%	878.59K
T. rowe price investment management	2.50M	0.27%	826.89K
Viking global investors lp	767.43K	0.37%	767.43K

Top Sellers

Holder	Shares	% Assets	Change
Ace management global	47.69K	100.00%	-917.81K
Farallon capital management	-	-	-397.00K
Mig capital	-	-	-381.73K
Two sigma investments, lp	39.89K	0.01%	-302.94K
Artisan partners limited partnership	-	-	-299.02K

New Positions

Holder	Shares	% Assets	Change	Value
Viking global investors lp	767.43K	0.37%	767.43K	$129.10M
Grantham, mayo, van otterloo	240.56K	0.12%	240.56K	$40.47M
Hawk ridge capital management lp	148.69K	1.04%	148.69K	$25.01M
Alpha wave global, lp	102.07K	1.85%	102.07K	$17.17M
Pfm health sciences, lp	94.45K	1.36%	94.45K	$15.89M

Sold Out

Holder	Change
American capital advisory	-1.00
Clearstead trust	-1.00
Pacific capital wealth advisors	-2.00
Claris advisors, llc / mo /	-2.00
Financial synergies wealth advisors	-2.00

Institutional Ownership Trends

Date	Holdings	Change %	Shares	Change %	Ownership	Change %	Increased Position	Change %	Decreased Position	Change %
Jun 30, 2025	375	-5.54%	56,778,550	4.69%	105	1.04%	171	-19.34%	132	11.86%
Mar 31, 2025	392	5.38%	54,108,094	5.12%	100	1.08%	209	20.11%	117	-4.10%
Dec 31, 2024	343	-8.78%	49,007,771	-2.29%	91	1.04%	159	-5.36%	111	-8.26%
Sep 30, 2024	371	1.64%	49,915,730	1.01%	93	1.08%	169	-	117	6.36%
Jun 30, 2024	363	2.54%	49,413,792	-3.99%	93	0.98%	167	20.14%	110	-18.52%

Top Mutual Funds Shareholders

Holder	Shares	% Holding	Change
MFS Mid Cap Growth Equity	1.68M	3.09%	230.99K
MFS Mid Cap Growth A	1.63M	3.00%	-43.77K
Vanguard US Total Market Shares ETF	1.53M	2.83%	-71.94K
Vanguard Total Stock Mkt Idx Inv	1.53M	2.82%	-32.31K
iShares Core S&P Mid-Cap ETF	1.47M	2.70%	-2.64K
Fidelity Select Health Care	1.40M	2.58%	10.06K
Fidelity Select Medical Tech and Devcs	1.32M	2.43%	-25.43K
American Funds SMALLCAP World A	1.21M	2.24%	65.00K
BlackRock Mid-Cap Growth Equity Instl	1.20M	2.20%	-18.64K
Vanguard Small Cap Index	1.18M	2.18%	-7.90K

Recent Insider Transactions

Date	Name	Role	Activity	Value
Aug 12, 2025	Brennan Michelle	Chairman of the Board	Buy	$15.04K
Aug 13, 2025	Brennan Michelle	Chairman of the Board	Buy	$15.53K
Aug 11, 2025	Jellison William R	-	Buy	$437.94K
May 12, 2025	Muhsin Bilal	Chief Operating Officer	Sell	$631.51K
May 12, 2025	Muhsin Bilal	Chief Operating Officer	Sell	$914.66K

Insider Transactions Trends

Date	Buy	Sell
2025 Q3	3	-
2025 Q2	-	3
2025 Q1	-	9
2024 Q4	-	-
2024 Q3	-	-

MASI Ownership FAQ

Who Owns Masimo?

Masimo shareholders are primarily institutional investors at 105.15%, followed by 5.97% insiders and -11.12% retail investors. The average institutional ownership in Masimo's industry, Medical Instruments & Supplies Stocks, is 56.90%, which Masimo exceeds.

Who owns the most shares of Masimo?

Masimo’s largest shareholders are Blackrock funding, inc. /de (10.51M shares, 19.46%), Blackrock (9.35M shares, 17.64%), and Fmr (8.1M shares, 15.16%). Together, they hold 52.27% of Masimo’s total shares outstanding.

Does Blackrock own Masimo?

Yes, BlackRock owns 17.64% of Masimo, totaling 9.35M shares as of Jun 2024. This represents 0.03% of BlackRock's total assets, with a market value of 1.18B$. In the last quarter, BlackRock increased its holdings by 1.47M shares, a 18.66% change.

Who is Masimo’s biggest shareholder by percentage of total assets invested?

Ace management global is Masimo’s biggest shareholder by percentage of total assets invested, with 100.00% of its assets in 47.69K Masimo shares, valued at 7.88M$.

Who is the top mutual fund holder of Masimo shares?

MFS Mid Cap Growth Equity is the top mutual fund holder of Masimo shares, with 3.09% of its total shares outstanding invested in 1.68M Masimo shares.

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