Masimo
MASI
MASI was delisted on the 9th of June, 2026.
445 hedge funds and large institutions have $9.48B invested in Masimo in 2026 Q1 according to their latest regulatory filings, with 132 funds opening new positions, 139 increasing their positions, 106 reducing their positions, and 71 closing their positions.
988% more call options, than puts
Call options by funds: $276M | Put options by funds: $25.3M
225% more funds holding in top 10
Funds holding in top 10: 4 → 13 (+9)
86% more first-time investments, than exits
New positions opened: 132 | Existing positions closed: 71
31% more repeat investments, than reductions
Existing positions increased: 139 | Existing positions reduced: 106
31% more capital invested
Capital invested by funds: $7.24B → $9.48B (+$2.24B)
14% more funds holding
Funds holding: 390 → 445 (+55)
4.13% less ownership
Funds ownership: 103.67% → 99.54% (-4.1%)
Top Buyers
| Rank | Fund | Capital Flow |
|---|---|---|
| 1 |
PCM
Pentwater Capital Management
Naples,
Florida
|
+$498M |
| 2 |
Barclays
London,
United Kingdom
|
+$422M |
| 3 |
HI
HBK Investments
Dallas,
Texas
|
+$404M |
| 4 |
Millennium Management
New York
|
+$126M |
| 5 |
Balyasny Asset Management
Chicago,
Illinois
|
+$121M |
Top Sellers
| Rank | Fund | Capital Flow |
|---|---|---|
| 1 |
Fidelity Investments
Boston,
Massachusetts
|
-$1.01B |
| 2 |
BlackRock
New York
|
-$661M |
| 3 |
T. Rowe Price Investment Management
Baltimore,
Maryland
|
-$303M |
| 4 |
NCMU
NAYA Capital Management (UK)
London,
United Kingdom
|
-$203M |
| 5 |
Westfield Capital Management
Boston,
Massachusetts
|
-$185M |
MASI Hedge Fund Activity: Q1 2026 in Review
445 of the 8,132 institutional investors tracked by Wall St. Rank reported a position in Masimo (MASI) for Q1 2026, worth a combined $9.48B — up 31% from $7.24B a quarter earlier.
Buyers outnumbered sellers: 132 funds opened new MASI positions and 71 closed out — a net gain of 61 holders — while 139 added to existing stakes and 106 trimmed.
The largest buyer was Pentwater Capital Management, opening a new position worth an estimated $498M. The largest seller was Fidelity Investments, cutting an estimated $1.01B.
- 445 institutional investors held Masimo (MASI) as of Q1 2026, up from 390 in Q4 2025.
- Funds reported $9.48B of Masimo stock for Q1 2026, up 31% quarter-over-quarter.
- 132 funds opened new Masimo positions in Q1 2026 and 71 closed out, a net change of +61 holders.
- The largest Masimo buyer in Q1 2026 was Pentwater Capital Management, an estimated $498M added.
- The largest Masimo seller in Q1 2026 was Fidelity Investments, an estimated $1.01B sold.
Based on aggregated 13F filings for Q1 2026.