Masimo Ownership | Who Owns Masimo?


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Masimo Ownership Summary


Masimo is owned by 18.88% institutional investors, 6.06% insiders, and 75.07% retail investors. Blackrock funding, inc. /de is the largest institutional shareholder, holding 19.19% 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


TypeName% Inst% Insiders% Retail
StockMasimo18.88%6.06%75.07%
SectorHealthcare Stocks 42.54%10.83%46.63%
IndustryMedical Instruments & Supplies Stocks40.77%13.85%45.38%

Institutional Shareholders


Top Institutional Shareholders by Total Shares

HolderShares% HoldingValue
Blackrock funding, inc. /de10.36M19.19%$1.53B
Blackrock9.35M17.64%$1.18B
Fmr8.21M15.21%$1.21B
Vanguard group4.81M8.91%$709.72M
Politan capital management lp4.59M8.50%$677.20M
Massachusetts financial services co /ma/2.62M4.85%$386.58M
T. rowe price investment management2.13M3.94%$313.80M
Capital research global investors1.85M3.43%$273.58M
State street1.48M2.75%$219.03M
Westfield capital management co lp1.42M2.63%$209.41M

Top Institutional Shareholders by % of Total Assets

HolderShares% AssetsValue
Ace management global47.69K100.00%$7.88M
Politan capital management lp4.59M61.54%$677.20M
Ensemble capital management407.10K3.99%$51.27M
Bridger management47.84K3.80%$7.06M
Lockerman financial group11.80K2.19%$1.74M
Pura vida investments25.00K1.99%$3.15M
Liontrust investment partners llp792.93K1.90%$131.07M
Alpha wave global, lp97.10K1.45%$14.33M
Rtw investments, lp683.29K1.24%$100.82M
Cramer rosenthal mcglynn114.61K1.05%$16.91M

Top Buyers

HolderShares% AssetsChange
Blackrock9.35M0.03%1.47M
Squarepoint ops620.93K0.09%546.90K
Millennium management408.06K0.03%378.81K
Viking global investors lp1.07M0.41%306.01K
Goldman sachs group744.40K0.01%272.88K

Top Sellers

HolderShares% AssetsChange
Holocene advisors, lp---1.24M
Ace management global47.69K100.00%-917.81K
Alliancebernstein53.56K0.00%-790.51K
Durable capital partners lp620.62K0.68%-543.28K
Farallon capital management---397.00K

New Positions

HolderShares% AssetsChangeValue
Adage capital partners gp150.00K0.04%150.00K$22.13M
Df dent108.65K0.21%108.65K$16.03M
Jupiter asset management84.66K0.11%84.66K$12.49M
Caption management70.30K0.14%70.30K$8.85M
Capital fund management34.42K0.01%34.42K$5.08M

Sold Out

HolderChange
Clearstead trust-1.00
Financial management professionals-1.00
American capital advisory-1.00
Claris advisors, llc / mo /-2.00
Advisornet financial-2.00

Institutional Ownership Trends


DateHoldingsChange %SharesChange %OwnershipChange %Increased PositionChange %Decreased PositionChange %
Sep 30, 2025147-61.21%10,193,987-82.28%180.17%58-66.67%54-59.40%
Jun 30, 2025375-5.54%56,778,5504.69%1051.04%171-19.34%13211.86%
Mar 31, 20253925.38%54,108,0945.12%1001.08%20920.11%117-4.10%
Dec 31, 2024343-8.78%49,007,771-2.29%911.04%159-5.36%111-8.26%
Sep 30, 20243711.64%49,915,7301.01%931.08%169-1176.36%

Top Mutual Funds Shareholders


HolderShares% HoldingChange
MFS Mid Cap Growth Equity1.68M3.09%230.99K
MFS Mid Cap Growth A1.63M3.00%-43.77K
Vanguard US Total Market Shares ETF1.53M2.83%-71.94K
Vanguard Total Stock Mkt Idx Inv1.53M2.82%-32.31K
iShares Core S&P Mid-Cap ETF1.46M2.70%-
Fidelity Select Health Care1.43M2.63%28.00K
Fidelity Select Medical Tech and Devcs1.35M2.49%30.00K
American Funds SMALLCAP World A1.21M2.24%65.00K
BlackRock Mid-Cap Growth Equity Instl1.20M2.20%-18.64K
Vanguard Small Cap Index1.18M2.18%-7.90K

Recent Insider Transactions


DateNameRoleActivityValue
Aug 12, 2025Brennan Michelle Chairman of the BoardBuy$15.04K
Aug 13, 2025Brennan Michelle Chairman of the BoardBuy$15.53K
Aug 11, 2025Jellison William R-Buy$437.94K
May 12, 2025Muhsin Bilal Chief Operating OfficerSell$631.51K
May 12, 2025Muhsin Bilal Chief Operating OfficerSell$914.66K

Insider Transactions Trends


DateBuySell
2025 Q33-
2025 Q2-3
2025 Q1-9
2024 Q4--
2024 Q3--

MASI Ownership FAQ


Who Owns Masimo?

Masimo shareholders are primarily institutional investors at 18.88%, followed by 6.06% insiders and 75.06% retail investors. The average institutional ownership in Masimo's industry, Medical Instruments & Supplies Stocks, is 40.77%, which Masimo falls below.

Who owns the most shares of Masimo?

Masimo’s largest shareholders are Blackrock funding, inc. /de (10.36M shares, 19.19%), Blackrock (9.35M shares, 17.64%), and Fmr (8.21M shares, 15.21%). Together, they hold 52.04% 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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