Masimo Corp (MASI) Institutional Ownership

Ownership Summary

Masimo Corp (NASDAQ:MASI) showed up in the 13F filings of 380 institutional investors as of December 2025.

• These investors held 102.7% of outstanding shares in December 2025, down from 105.6% in September 2025.
• Their total shares held in MASI increased 0.43% from the prior quarter, while the number of investors in Masimo increased 5.26% year over year.
• Of these 380 funds, 183 grew their exposure to Masimo, 128 cut back, and 69 maintained positions.
• The aggregate institutional position in Masimo amounted to 55.89Mn shares as of December 2025, up by 238.01K shares quarter on quarter, and up 2.84Mn shares year over year.
• BlackRock, Inc. is the top holder of Masimo as of December 31, 2025, with 4.64Mn shares representing 8.54% of outstanding stock.
• The biggest buyers of Masimo for the quarter ending December 2025 included Pentwater Capital Management LP (3.18Mn), Barclays Plc (2.69Mn), HBK INVESTMENTS L P (2.58Mn), VANGUARD CAPITAL MANAGEMENT LLC (2.05Mn), VANGUARD PORTFOLIO MANAGEMENT LLC (2.01Mn).
• The largest sellers of Masimo for the quarter ending December 2025 were FMR LLC (6.41Mn), BlackRock, Inc. (4.21Mn), WESTFIELD CAPITAL MANAGEMENT CO LP (1.18Mn), Ameriprise Financial Inc (403.2K), SCHRODER INVESTMENT MANAGEMENT GROUP (379.32K).
• Per Business Quant, the top 10 investors in MASI for the quarter ending December 2025 include BlackRock, Inc. (4.64Mn), Politan Capital Management LP (4.59Mn), Pentwater Capital Management LP (3.18Mn), Barclays Plc (2.74Mn), HBK INVESTMENTS L P (2.58Mn), MASSACHUSETTS FINANCIAL SERVICES CO /MA/ (2.34Mn), VANGUARD CAPITAL MANAGEMENT LLC (2.05Mn), VANGUARD PORTFOLIO MANAGEMENT LLC (2.01Mn), FMR LLC (1.45Mn), State Street Corp (1.44Mn).