Grantham, Mayo, Van Otterloo & Co (GMO)
MASI

Grantham, Mayo, Van Otterloo & Co (GMO)’s Masimo MASI Stock Holding History

Grantham, Mayo, Van Otterloo & Co (GMO)’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 		$24.5M Sell
137,617
-6,208
-4% -$974K 0.06% 159
2025
Q4 		$18.7M Sell
143,825
-98,997
-41% -$14.2M 0.05% 179
2025
Q3 		$35.8M Buy
242,822
+2,259
+0.9% +$342K 0.1% 107
2025
Q2 		$40.5M Buy
+240,563
New +$38.4M 0.12% 89
2020
Q2 		– Sell
-1,783
Closed -$316K – 800
2020
Q1 		$316K Sell
1,783
-6,800
-79% -$1.17M ﹤0.01% 653
2019
Q4 		$1.36M Sell
8,583
-500
-6% -$75.2K 0.01% 468
2019
Q3 		$1.35M Buy
+9,083
New +$1.38M 0.01% 501
2017
Q3 		– Sell
-2,300
Closed -$210K – 598
2017
Q2 		$210K Hold
2,300
– – ﹤0.01% 549
2017
Q1 		$214K Buy
+2,300
New +$189K ﹤0.01% 541
2016
Q2 		– Sell
-30,800
Closed -$1.29M – 602
2016
Q1 		$1.29M Sell
30,800
-300
-1% -$11.3K ﹤0.01% 405
2015
Q4 		$1.29M Sell
31,100
-4,300
-12% -$176K ﹤0.01% 377
2015
Q3 		$1.36M Hold
35,400
– – ﹤0.01% 369
2015
Q2 		$1.37M Sell
35,400
-17,500
-33% -$627K ﹤0.01% 340
2015
Q1 		$1.75M Sell
52,900
-1,700
-3% -$48.9K 0.01% 335
2014
Q4 		$1.44M Sell
54,600
-20,935
-28% -$517K ﹤0.01% 349
2014
Q3 		$1.61M Sell
75,535
-13,265
-15% -$303K ﹤0.01% 365
2014
Q2 		$2.1M Buy
88,800
+5,400
+6% +$134K 0.01% 360
2014
Q1 		$2.28M Buy
+83,400
New +$2.38M 0.01% 399

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

Grantham, Mayo, Van Otterloo & Co (GMO)'s MASI Position: Q1 2026 in Review

Grantham, Mayo, Van Otterloo & Co (GMO) reduced its Masimo (MASI) stake by 4.3% in Q1 2026, selling an estimated $974K and leaving 137,617 shares worth $24.5M. The position accounts for 0.06% of the portfolio, ranked #159.

Grantham, Mayo, Van Otterloo & Co (GMO) first reported a position in MASI in Q1 2014 and has held it in 18 quarters since. The position peaked at $40.5M in Q2 2025. 445 funds tracked by Wall St. Rank hold MASI as of Q1 2026.

  • Grantham, Mayo, Van Otterloo & Co (GMO) held 137,617 shares of Masimo worth $24.5M as of Q1 2026.
  • Grantham, Mayo, Van Otterloo & Co (GMO) sold 6,208 Masimo shares in Q1 2026, an estimated $974K.
  • Masimo made up 0.06% of Grantham, Mayo, Van Otterloo & Co (GMO)'s portfolio in Q1 2026, its #159 holding.
  • Grantham, Mayo, Van Otterloo & Co (GMO) first reported a position in Masimo in Q1 2014 and has held it in 18 quarters since.
  • Grantham, Mayo, Van Otterloo & Co (GMO)'s Masimo position peaked at $40.5M in Q2 2025.
  • 445 funds tracked by Wall St. Rank held Masimo as of Q1 2026.

Based on Grantham, Mayo, Van Otterloo & Co (GMO)'s 13F filing for Q1 2026, filed 14 May 2026.