Adage Capital Partners
MASI

Adage Capital Partners’s Masimo MASI Stock Holding History

Adage Capital Partners’s Portfolio MASI Stock Details MASI Fund Activity
Bought
Maintained
Sold
Quarter Market Value Status Shares Change in
Stake 		Trade Value Portfolio Weight Portfolio Position
2025
Q4 		– Sell
-150,000
Closed -$22.1M – 969
2025
Q3 		$22.1M Buy
+150,000
New +$22.7M 0.04% 436
2022
Q1 		– Sell
-80,000
Closed -$23.4M – 1110
2021
Q4 		$23.4M Buy
+80,000
New +$22.8M 0.04% 407
2014
Q4 		– Sell
-250,000
Closed -$5.32M – 747
2014
Q3 		$5.32M Buy
+250,000
New +$5.71M 0.01% 608

Other funds holding MASI

BlackRock
BlackRock New York $5.72T AUM 30.48% 1-Year Est. Return
Fidelity Investments
Fidelity Investments Boston, Massachusetts $1.9T AUM 41.92% 1-Year Est. Return
PCM
Politan Capital Management New York $985M AUM 3.12% 1-Year Est. Return
Vanguard Group
Vanguard Group Malvern, Pennsylvania $6.9T AUM 27.45% 1-Year Est. Return
Massachusetts Financial Services
Massachusetts Financial Services Boston, Massachusetts $298B AUM 21.96% 1-Year Est. Return
T. Rowe Price Investment Management
T. Rowe Price Investment Management Baltimore, Maryland $145B AUM 22.78% 1-Year Est. Return
NCMU
NAYA Capital Management (UK) London, United Kingdom $1.18B AUM 13.14% 1-Year Est. Return
Westfield Capital Management
Westfield Capital Management Boston, Massachusetts $23.8B AUM 49.45% 1-Year Est. Return
State Street
State Street Boston, Massachusetts $2.9T AUM 29.55% 1-Year Est. Return
Alyeska Investment Group
Alyeska Investment Group Chicago, Illinois $35.4B AUM 33.54% 1-Year Est. Return

Adage Capital Partners's MASI Position: Q4 2025 in Review

Adage Capital Partners sold out of Masimo (MASI) in Q4 2025, closing a stake of 150,000 shares — an estimated $22.1M sold.

Adage Capital Partners first reported a position in MASI in Q3 2014 and held it in 3 quarters. The position peaked at $23.4M in Q4 2021. 390 funds tracked by Wall St. Rank hold MASI as of Q4 2025.

  • Adage Capital Partners reported no remaining Masimo position as of Q4 2025 after selling out during the quarter.
  • Adage Capital Partners sold 150,000 Masimo shares in Q4 2025, an estimated $22.1M.
  • Adage Capital Partners first reported a position in Masimo in Q3 2014 and held it in 3 quarters.
  • Adage Capital Partners's Masimo position peaked at $23.4M in Q4 2021.
  • 390 funds tracked by Wall St. Rank held Masimo as of Q4 2025.

Based on Adage Capital Partners's 13F filing for Q4 2025, filed 17 Feb 2026.