MF
MASI

Magnetar Financial’s Masimo MASI Stock Holding History

Magnetar Financial’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
2026
Q1 		$76M Buy
427,081
+421,626
+7,729% +$66.2M 0.77% 13
2025
Q4 		$709K Buy
+5,455
New +$781K 0.01% 493
2022
Q2 		– Sell
-7,866
Closed -$1.15M – 1762
2022
Q1 		$1.15M Buy
7,866
+6,476
+466% +$1.24M 0.01% 775
2021
Q4 		$407K Buy
+1,390
New +$396K ﹤0.01% 1007
2021
Q2 		– Sell
-9,772
Closed -$2.24M – 1304
2021
Q1 		$2.24M Buy
+9,772
New +$2.45M 0.02% 550
2020
Q3 		– Sell
-1,122
Closed -$256K – 703
2020
Q2 		$256K Buy
+1,122
New +$246K 0.01% 360
2017
Q3 		– Sell
-3,487
Closed -$318K – 826
2017
Q2 		$318K Buy
+3,487
New +$320K ﹤0.01% 562
2016
Q1 		– Sell
-5,114
Closed -$212K – 429
2015
Q4 		$212K Buy
+5,114
New +$209K ﹤0.01% 324

Other funds holding MASI

BlackRock
BlackRock New York $5.72T AUM 30.48% 1-Year Est. Return
PCM
Politan Capital Management New York $985M AUM 3.12% 1-Year Est. Return
PCM
Pentwater Capital Management Naples, Florida $19.3B AUM 58.13% 1-Year Est. Return
Barclays
Barclays London, United Kingdom $416B AUM 33.63% 1-Year Est. Return
HI
HBK Investments Dallas, Texas $9.85B AUM 55.6% 1-Year Est. Return
Massachusetts Financial Services
Massachusetts Financial Services Boston, Massachusetts $298B AUM 21.96% 1-Year Est. Return
VCM
Vanguard Capital Management Malvern, Pennsylvania $4.04T AUM
VPM
Vanguard Portfolio Management Malvern, Pennsylvania $1.91T AUM
Fidelity Investments
Fidelity Investments Boston, Massachusetts $1.9T AUM 41.92% 1-Year Est. Return
State Street
State Street Boston, Massachusetts $2.9T AUM 29.55% 1-Year Est. Return

Magnetar Financial's MASI Position: Q1 2026 in Review

Magnetar Financial increased its Masimo (MASI) stake by 7,729% in Q1 2026, buying an estimated $66.2M and bringing the position to 427,081 shares worth $76M. The position accounts for 0.77% of the portfolio, ranked #13.

Magnetar Financial first reported a position in MASI in Q4 2015 and has held it in 8 quarters since. 445 funds tracked by Wall St. Rank hold MASI as of Q1 2026.

  • Magnetar Financial held 427,081 shares of Masimo worth $76M as of Q1 2026.
  • Magnetar Financial bought 421,626 Masimo shares in Q1 2026, an estimated $66.2M.
  • Masimo made up 0.77% of Magnetar Financial's portfolio in Q1 2026, its #13 holding.
  • Magnetar Financial first reported a position in Masimo in Q4 2015 and has held it in 8 quarters since.
  • 445 funds tracked by Wall St. Rank held Masimo as of Q1 2026.

Based on Magnetar Financial's 13F filing for Q1 2026, filed 13 May 2026.