Masimo Ownership | Who Owns Masimo?

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Masimo Ownership Summary

Masimo is owned by 16.04% institutional investors, 4.81% insiders, and 79.15% retail investors. Blackrock is the largest institutional shareholder, holding 17.64% of MASI shares. MFS Mid Cap Growth A is the top mutual fund, with 3.15% of its assets in Masimo shares.

MASI Ownership Benchmark

Type	Name	% Inst	% Insiders	% Retail
Stock	Masimo	16.04%	4.81%	79.15%
Sector	Healthcare Stocks	232.86%	10.65%	-143.51%
Industry	Medical Instruments & Supplies Stocks	32.32%	13.56%	54.11%

Institutional Shareholders

Top Institutional Shareholders by Total Shares

Holder	Shares	% Holding	Value
Blackrock	9.35M	17.64%	$1.18B
Blackrock funding, inc. /de	8.86M	16.40%	$1.15B
Fmr	8.21M	15.21%	$1.21B
Politan capital management lp	4.59M	8.50%	$677.20M
Vanguard group	4.35M	8.05%	$565.60M
Massachusetts financial services co /ma/	2.66M	4.93%	$346.46M
T. rowe price investment management	2.13M	3.94%	$313.80M
Westfield capital management co lp	1.52M	2.82%	$197.96M
State street	1.48M	2.75%	$219.03M
Alyeska investment group	1.38M	2.56%	$203.78M

Top Institutional Shareholders by % of Total Assets

Holder	Shares	% Assets	Value
Ace management global	47.69K	100.00%	$7.88M
Politan capital management lp	4.59M	61.54%	$677.20M
Cibra capital	90.38K	7.76%	$16.08M
Ensemble capital management	407.10K	3.99%	$51.27M
Bridger management	47.84K	3.80%	$7.06M
Lockerman financial group	10.50K	3.36%	$1.87M
Pura vida investments	25.00K	1.99%	$3.15M
Alpine associates management	189.00K	1.98%	$33.62M
Liontrust investment partners llp	792.93K	1.90%	$131.07M
Alpha wave global, lp	97.10K	1.45%	$14.33M

Top Buyers

Holder	Shares	% Assets	Change
Blackrock	9.35M	0.03%	1.47M
Squarepoint ops	620.93K	0.09%	546.90K
Sg americas securities	522.82K	0.10%	506.39K
Ubs group	599.27K	0.01%	429.47K
Millennium management	408.06K	0.03%	378.81K

Top Sellers

Holder	Shares	% Assets	Change
Blackrock funding, inc. /de	8.86M	0.02%	-1.51M
Holocene advisors, lp	-	-	-1.24M
Capital research global investors	637.89K	0.02%	-1.22M
Ace management global	47.69K	100.00%	-917.81K
Alliancebernstein	53.56K	0.00%	-790.51K

New Positions

Holder	Shares	% Assets	Change	Value
Norges bank	377.42K	0.01%	377.42K	$49.09M
Alpine associates management	189.00K	1.98%	189.00K	$33.62M
Adage capital partners gp	150.00K	0.04%	150.00K	$22.13M
Df dent	108.65K	0.21%	108.65K	$16.03M
Hrt financial lp	92.78K	0.04%	92.78K	$12.07M

Sold Out

Holder	Change
Financial management professionals	-1.00
Clearstead trust	-1.00
Claris advisors, llc / mo /	-2.00
Advisornet financial	-2.00
Twin peaks wealth advisors	-2.00

Institutional Ownership Trends

Date	Holdings	Change %	Shares	Change %	Ownership	Change %	Increased Position	Change %	Decreased Position	Change %
Dec 31, 2025	126	-65.00%	8,662,748	-84.58%	16	0.15%	52	-68.29%	38	-68.85%
Sep 30, 2025	147	-61.21%	10,193,987	-82.28%	18	0.17%	58	-66.67%	54	-59.40%
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%

Top Mutual Funds Shareholders

Holder	Shares	% Holding	Change
MFS Mid Cap Growth A	1.64M	3.15%	-
MFS Mid Cap Growth Equity	1.64M	3.15%	-
iShares Core S&P Mid-Cap ETF	1.51M	2.90%	2.70K
Vanguard US Total Market Shares ETF	1.53M	2.83%	-71.94K
Vanguard Total Stock Mkt Idx Inv	1.45M	2.77%	7.11K
BlackRock Mid-Cap Growth Equity Instl	1.20M	2.20%	-18.64K
Vanguard Small Cap Index	1.05M	2.01%	17.18K
BlackRock Global Uncons Eq Z USD Acc	1.06M	1.96%	31.08K
Fidelity Select Health Care	1.00M	1.92%	-230.00K
BlackRock Event Driven Equity Instl	971.82K	1.86%	308.48K

Recent Insider Transactions

Date	Name	Role	Activity	Value
Jan 28, 2026	Sampath Anand	EVP, Ops & Clinical Research	Sell	$27.07K
Jan 28, 2026	Sampath Anand	EVP, Ops & Clinical Research	Sell	$900.16K
Jan 28, 2026	Sampath Anand	EVP, Ops & Clinical Research	Sell	$1.63M
Aug 12, 2025	Brennan Michelle	Chairman of the Board	Buy	$15.04K
Aug 13, 2025	Brennan Michelle	Chairman of the Board	Buy	$15.53K

Insider Transactions Trends

Date	Buy	Sell
2026 Q1	-	3
2025 Q4	-	-
2025 Q3	3	-
2025 Q2	-	3
2025 Q1	-	9

MASI Ownership FAQ

Who Owns Masimo?

Masimo shareholders are primarily institutional investors at 16.04%, followed by 4.81% insiders and 79.15% retail investors. The average institutional ownership in Masimo's industry, Medical Instruments & Supplies Stocks, is 32.32%, which Masimo falls below.

Who owns the most shares of Masimo?

Masimo’s largest shareholders are Blackrock (9.35M shares, 17.64%), Blackrock funding, inc. /de (8.86M shares, 16.40%), and Fmr (8.21M shares, 15.21%). Together, they hold 49.25% 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 A is the top mutual fund holder of Masimo shares, with 3.15% of its total shares outstanding invested in 1.64M Masimo shares.

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