Danaher to buy Masimo in $9.9 billion deal in diagnostics push

IRVINE, Calif. – Danaher, a $150 billion U.S. company that makes tools used in developing and testing medicines, has agreed to buy Masimo for $9.9 billion, expanding in patient-monitoring devices in a surprise move outside its main focus.

California-based Masimo is best known for the devices hospitals use to measure bloodoxygen levels, including the pulse oximeters clipped to a patient’s finger, along with other noninvasive monitors that track breathing and brain activity.

Masimo has drawn attention beyond hospitals because of a long-running patent dispute with Apple over bloodoxygen technology used in smartwatches.

The market for blood oxygen monitoring products is dominated by rival Medtronic and Masimo.

Julie Sawyer Montgomery (pictured), executive vice president for diagnostics, Danaher, said: “Masimo’s advanced sensor technology and AI-enabled monitoring bring powerful new capabilities to our diagnostics portfolio. Integrating these strengths into Danaher will create meaningful opportunities to innovate for clinicians and improve decision making in critical settings.”

Upon completion of the transaction, Masimo will be a standalone operating company within Danaher’s Diagnostics segment along with Radiometer, Leica Biosystems, Cepheid and Beckman Coulter Diagnostics.

J.P. Morgan analysts said the move was unexpected, noting that investors had anticipated Danaher would target acquisitions closer to its core lifesciences and diagnostics businesses.

They warned the shift toward patientmonitoring equipment could pressure the shares in the short term, as it may signal that opportunities in Danaher’s traditional markets are less attractive in the current environment.

At the same time, they said Masimo’s high share in pulseoximetry, strong recurringrevenue base and margin expansion potential fit Danaher’s longstanding playbook of buying standalone units with room to grow.

Bernstein analyst Christian Moore expects the acquisition to prove to be a good one for Danaher over time.

The deal with Masimo broadens Danaher’s diagnostic segment, complementing its invasive Radiometer blood analyzer devices with Masimo’s non-invasive pulse oximeters, brain function and respiration monitoring devices, among other products.

Masimo recently transformed itself into a “pure-play” medical technology firm after selling its Sound United unit, which held audio brands Denon and Marantz, to Samsung’s Harman last year for $350 million.

The deal is expected to close by the second half of 2026.