Masimo

Corporate brand

Masimo is a U.S. medical-technology brand specializing in noninvasive patient monitoring, sensors, connectivity, and healthcare automation.

Last updated November 4, 2026

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Overview

Masimo is an American medical-technology company and healthcare brand headquartered in Irvine, California. Founded in 1989 by engineer Joe Kiani, the company built its reputation around noninvasive physiological monitoring, particularly pulse oximetry intended to remain reliable during patient motion and low-perfusion conditions. Its core Signal Extraction Technology, commonly known as Masimo SET, uses signal-processing techniques to separate arterial signals from noise and venous interference. The technology became the foundation for a large installed base of hospital monitors, OEM monitoring modules, reusable and disposable sensors, and connected clinical systems. Masimo primarily serves hospitals, emergency medical services, outpatient and procedural environments, home-care providers, physician offices, long-term-care facilities, and veterinary customers. Its portfolio covers bedside, handheld, wearable, and remote monitoring. Major technology areas include pulse oximetry, pulse co-oximetry, noninvasive hemoglobin and blood-constituent monitoring, acoustic respiration-rate measurement, brain-function monitoring, regional oximetry, capnography, gas analysis, hemodynamic monitoring, telehealth, and hospital connectivity. The company sells directly and through distributors, while also licensing or supplying technologies to original-equipment manufacturers including major patient-monitoring companies. The Masimo SET platform was introduced in the 1990s and became associated with motion-tolerant and low-perfusion pulse oximetry. Masimo later expanded into rainbow Pulse CO-Oximetry, which uses multiple wavelengths of light to estimate additional parameters such as total hemoglobin, carboxyhemoglobin, methemoglobin, and oxygen-reserve indicators. Its broader Hospital Automation portfolio has included Patient SafetyNet, Iris Gateway, UniView, Replica, and related connectivity and notification systems designed to move patient data across hospital workflows and support earlier clinical intervention. Masimo also developed products for the home and consumer markets. Masimo SafetyNet was introduced as a remote-care and telehealth platform using connected sensors, smartphones, and a cloud-based service. The company launched the W1 Medical Watch in 2022, extending Masimo’s physiological-monitoring capabilities into a wearable form factor. In 2020, it introduced Bridge, a neuromodulation product intended to help reduce opioid-withdrawal symptoms. In 2023, Masimo received FDA De Novo authorization for a pulse-oximetry-based device designed to provide an alert related to respiratory depression and potential opioid overdose, with prescription and over-the-counter distribution pathways. Masimo became publicly traded in 2007 under the Nasdaq ticker MASI. Its corporate strategy broadened significantly in 2022 when it acquired Sound United, a consumer-audio platform whose portfolio included brands such as Bowers & Wilkins, Denon, Marantz, Polk Audio, Definitive Technology, Classé, and Boston Acoustics. Masimo described the transaction as a way to expand retail distribution, add engineering resources, and create potential connected-home hubs for health services. The diversification produced strategic and governance tensions, and Masimo later agreed to sell the consumer-audio division to Harman International, a Samsung subsidiary, for approximately $350 million in 2025. The company was involved in a prominent patent dispute with Apple concerning pulse-oximetry technology used in Apple Watch products. In October 2023, the U.S. International Trade Commission found that Apple infringed Masimo patents related to light-based blood-oxygen monitoring. The dispute became one of the most visible examples of conflict between a specialized medical-device company and a major consumer-electronics platform. Masimo experienced a leadership transition in 2024 and 2025 following a proxy contest involving activist investor Politan Capital Management. Founder…

History

Masimo was founded in 1989 by engineer Joe Kiani, with Mohamed Diab later contributing as a co-developer. The company emerged from an effort to improve pulse-oximetry reliability in circumstances where conventional systems could be affected by motion, weak circulation, or interference from venous blood. Its early technology work led to Signal Extraction Technology, or SET, a signal-processing platform designed to distinguish the arterial component of an optical signal from noise and other physiological signals. During the 1990s, Masimo commercialized SET-based pulse oximetry through its own monitors, sensors, and technology modules supplied to original-equipment manufacturers. This business model allowed Masimo technology to appear in a variety of hospital-monitoring systems while the company continued developing proprietary sensors and software. The company’s technology became especially associated with monitoring patients in intensive care, operating rooms, neonatal care, emergency medicine, and transport settings. Masimo expanded beyond oxygen saturation measurement in the 2000s. In 2005, it introduced rainbow Pulse CO-Oximetry, a multiwavelength platform intended to estimate additional blood constituents noninvasively. Depending on the device and clearance, the platform could support measurements such as total hemoglobin, carboxyhemoglobin, methemoglobin, perfusion-related indices, and oxygen-reserve indicators. The company also developed spot-check devices such as Pronto-7 and broadened its monitoring portfolio to include capnography, gas analysis, brain-function monitoring, regional oximetry, acoustic respiration-rate monitoring, and hemodynamic technologies. The company became publicly traded in 2007 on Nasdaq under the symbol MASI. Its hospital business developed from individual monitors and sensors into a connected ecosystem. Products such as Root provided an expandable platform for combining Masimo and third-party measurements, while Patient SafetyNet and related software supported remote alarms, centralized surveillance, workflow integration, and escalation of clinically important events. Masimo’s commercial model increasingly emphasized recurring sensor consumption, installed-base expansion, software, connectivity, and long-term hospital contracts. In 2012, Masimo received FDA 510(k) clearance for devices and sensors labeled for newborn screening for critical congenital heart disease when used with physical examination. The company’s PVI technology was also referenced by healthcare organizations in discussions and guidance concerning perioperative fluid management and hemodynamic optimization. These developments reinforced Masimo’s identity as a clinical-monitoring specialist rather than merely a maker of consumer pulse oximeters. Masimo continued to expand into remote and home monitoring. During the COVID-19 pandemic, it introduced Masimo SafetyNet, a telehealth and remote-patient-monitoring system linking sensors with smartphones and a cloud platform. The company also entered the opioid-care field. Bridge, launched in 2020, is a neuromodulation device intended to reduce opioid-withdrawal symptoms. In 2023, the FDA granted De Novo authorization to an additional pulse-oximetry-based device intended to alert to respiratory depression as a potential early indicator of opioid overdose. Masimo’s corporate strategy changed sharply in 2022 with its acquisition of Sound United, a large consumer-audio business whose brands included Bowers & Wilkins, Denon, Marantz, Polk Audio, Definitive Technology, Classé, and Boston Acoustics. Masimo said the transaction could expand retail reach, provide engineering resources, and create connected audio products that might function as hubs for future health services. The acquisition also created a strategic tension between Masimo’s core medical-device identity and its consumer-electronics ambitions. In 2025, Masimo agreed to sell Sound United to Harman International, a subsidiary of Samsung Electronics, for approximately $350 million, refocusing the company on medical technology. Masimo’s history also includes a major intellectual-property conflict with Apple. Beginning in 2020, the companies became involved in litigation and regulatory proceedings concerning pulse-oximetry patents and Apple Watch products. In October 2023, the U.S. International Trade Commission found that Apple infringed Masimo patents related to light-based blood-oxygen monitoring. Masimo asserted that Apple had recruited employees after discussions about a possible partnership; Apple disputed Masimo’s characterization and said it had evaluated multiple vendors. Governance became another major turning point. In 2024, activist investor Politan Capital Management mounted a proxy contest focused on Masimo’s governance, capital allocation, and diversification strategy. Joe Kiani resigned as CEO in September 2024. Michelle Brennan, a Masimo director, became interim CEO, and Catherine Szyman was selected as permanent CEO effective February 12, 2025. Brennan became chair of the board, while Quentin Koffey, associated with Politan, became vice-chair. In February 2026, Danaher announced an agreement to acquire Masimo for approximately $9.9 billion in enterprise value. Masimo shareholders approved the transaction in May, and Danaher completed it on June 10, 2026. Masimo’s stock ceased trading on Nasdaq, and the company became a wholly owned Danaher subsidiary. Danaher stated that Masimo would remain a standalone operating company within its Diagnostics segment, preserving the Masimo brand while combining its monitoring, sensor, connectivity, and artificial-intelligence capabilities with Danaher’s global scale.

2026
Danaher acquisition is completed
[8]Danaher Completes Acquisition of Masimo Corporationmasimo.com
Danaher completed its acquisition of Masimo on June 10, 2026, ending Masimo’s public listing while retaining the operating brand.
2025
Catherine Szyman becomes CEO
[4]Masimo Leadership Transition Filingsec.gov
Catherine Szyman became CEO on February 12, 2025, while Michelle Brennan became board chair.
2025
Sound United sale is announced
[11]Sound United sale is announcedmasimo.com
Masimo agreed to sell its consumer-audio division to Harman International for approximately $350 million.
2024
Joe Kiani leaves the CEO role
[3]Masimo Fiscal Year 2025 Form 10-K Amendmentsec.gov
Founder Joe Kiani resigned as CEO following a proxy contest involving Politan Capital Management.
2023
FDA De Novo authorization for respiratory-depression alert device
[1]Masimoen.wikipedia.org
Masimo received FDA De Novo authorization for a pulse-oximetry-based device designed to alert to respiratory depression and potential opioid overdose.
2023
ITC rules in Masimo’s favor in Apple patent dispute
[1]Masimoen.wikipedia.org
The U.S. International Trade Commission found that Apple infringed Masimo patents related to light-based pulse-oximetry monitoring.
2022
Masimo acquires Sound United
[1]Masimoen.wikipedia.org
The acquisition added a large consumer-audio portfolio and expanded Masimo’s retail and consumer-electronics presence.
2022
W1 Medical Watch launches
[10]W1 Medical Watch launchessec.gov
Masimo entered the medical-wearable market with the W1 Medical Watch.
2020
Bridge neuromodulation device launches
[1]Masimoen.wikipedia.org
Masimo released Bridge, a neuromodulation device intended to reduce symptoms associated with opioid withdrawal.
2020
Masimo SafetyNet is introduced
[1]Masimoen.wikipedia.org
Masimo introduced a remote-care platform using connected sensors, smartphones, and cloud-based monitoring.
2013
Root platform is introduced
[9]Masimo SET is introducedsec.gov
Masimo introduced Root, an expandable patient-monitoring and connectivity platform designed to combine multiple Masimo and third-party technologies.
2012
FDA clearance for newborn critical-congenital-heart-disease screening
[1]Masimoen.wikipedia.org
Masimo received FDA 510(k) clearance for devices and sensors labeled for newborn screening for critical congenital heart disease when used with physical examination.
2007
Masimo becomes publicly traded
[1]Masimoen.wikipedia.org
Masimo began trading publicly on Nasdaq under the ticker MASI.
2005
Rainbow Pulse CO-Oximetry expands measurement scope
[9]Masimo SET is introducedsec.gov
Masimo introduced a multiwavelength platform capable of estimating additional blood constituents and physiological parameters without conventional invasive sampling.
1995
Masimo SET is introduced
[9]Masimo SET is introducedsec.gov
Masimo introduced its Measure-through Motion and Low Perfusion pulse-oximetry technology, later branded Masimo SET.
1989
Masimo is founded
[1]Masimoen.wikipedia.org
Engineer Joe Kiani founded Masimo in the United States, with Mohamed Diab later joining as a co-developer.

Products and positioning

A specialist medical-technology brand positioned around clinically oriented, noninvasive monitoring; sensor and signal-processing expertise; continuous surveillance; hospital connectivity; and increasingly connected care in home and acute-care settings.

Signal-processing pulse oximetry · 1995
Masimo SET
Masimo SET is the company’s core pulse-oximetry platform. It combines optical sensing with signal-processing algorithms intended to distinguish arterial signals from motion, low-perfusion conditions, and other sources of interference. SET technology is embedded in bedside, handheld, wearable, and OEM monitoring products and supports measurements such as oxygen saturation, pulse rate, perfusion index, and pleth variability index.
Multiwavelength blood-constituent monitoring · 2005
rainbow Pulse CO-Oximetry
Rainbow Pulse CO-Oximetry extends conventional pulse oximetry by using multiple wavelengths of light to estimate additional blood and physiological parameters. Depending on the cleared device and sensor, the platform can support noninvasive measurements including total hemoglobin, carboxyhemoglobin, methemoglobin, oxygen content, perfusion indices, and oxygen-reserve indicators.
Patient-monitoring and connectivity platform · 2013
Root
Root is an expandable patient-monitoring platform designed to aggregate measurements from Masimo technologies and selected third-party modules. It functions as a flexible hub for bedside monitoring, connectivity, and clinical applications, and has supported additions such as SedLine brain-function monitoring, O3 regional oximetry, and capnography.
Bedside and handheld pulse CO-oximeter
Radical-7
Radical-7 is a Masimo patient monitor incorporating SET pulse oximetry and, in compatible configurations, rainbow measurements. It is used in hospital and transport environments for continuous or spot monitoring and can connect with disposable or reusable sensors and broader Masimo clinical platforms.
Wireless wearable monitor
Radius-7
Radius-7 is a tetherless wearable monitoring system designed to transmit physiological measurements without requiring a conventional wired connection to the bedside monitor. It supports continuous patient surveillance and is intended for hospital workflows where mobility, transport, or reduced cable burden is important.
Brain-function monitoring
SedLine
SedLine is a brain-function monitoring system that analyzes electroencephalographic activity from both hemispheres to generate an index used by clinicians when assessing anesthetic depth and brain activity during procedures. The system is designed to complement clinical judgment rather than replace it.
Remote patient surveillance and notification
Patient SafetyNet
Patient SafetyNet is a hospital notification and remote-monitoring system used to support continuous surveillance on medical-surgical and other care floors. It links patient sensors, monitoring infrastructure, and notification workflows so that abnormal conditions can be escalated to clinical staff.
Remote patient monitoring and telehealth · 2020
Masimo SafetyNet
Masimo SafetyNet is a connected-care platform for remote patient monitoring. It uses compatible sensors, smartphones, and a cloud-based service to transmit physiological data and support clinician oversight outside traditional hospital settings, including home-based and post-discharge care.
Medical wearable · 2022
W1 Medical Watch
The W1 Medical Watch is a wearable monitoring product that brings Masimo physiological-measurement capabilities into a watch form factor. It was designed to connect consumer-oriented wearability with Masimo’s clinical-monitoring and telehealth ecosystem.
Neuromodulation device · 2020
Bridge
Bridge is a neuromodulation device intended to reduce symptoms associated with opioid withdrawal. Its introduction broadened Masimo’s portfolio beyond monitoring into a treatment-oriented product category related to substance-use care.

Controversies

2024
Proxy contest and leadership dispute
Masimo became the subject of a high-profile governance dispute involving activist investor Politan Capital Management. The contest focused on board composition, capital allocation, corporate strategy, and the Sound United diversification. Founder and CEO Joe Kiani left the CEO role in September 2024, after which Michelle Brennan became interim CEO.
Source
2020
Masimo sues Apple over Apple Watch technology
Masimo and its spin-off Cercacor filed suit against Apple, alleging that Apple obtained confidential information and infringed 10 patents by using related inventions in Apple Watch products. The allegations are not presented as a court determination.
Source 1 Source 2

2026
Acquisition by DanaherM&A
Background
Danaher sought to strengthen its Diagnostics portfolio with Masimo’s pulse-oximetry, sensor, monitoring, connectivity, and artificial-intelligence capabilities.
Action taken
Danaher acquired all outstanding Masimo shares for $180 per share in cash and completed the transaction on June 10, 2026.
Aftermath
Masimo became a wholly owned subsidiary and standalone operating company within Danaher’s Diagnostics segment; its Nasdaq listing ended.
enterprise value. Approximately $9.9 billion (February 17, 2026 announcement; completed June 10, 2026)
Source
2025
Sale of Sound United to HarmanM&A
Background
Masimo reassessed the role of consumer audio after governance disputes and a renewed emphasis on patient monitoring.
Action taken
Masimo agreed to sell Sound United to Harman International, a subsidiary of Samsung Electronics, for approximately $350 million.
Aftermath
The divestiture reduced Masimo’s consumer-electronics exposure and supported a more focused medical-technology strategy.
announced sale consideration. $350 million (May 2025 announcement)
Source
2024
Leadership reset after proxy contestStrategy
Background
An activist investor challenged Masimo’s governance and diversification strategy, including the company’s involvement in consumer audio.
Action taken
Joe Kiani left the CEO role, Michelle Brennan became interim CEO, and the board began a permanent CEO search.
Aftermath
The transition led to the appointment of Catherine Szyman as CEO in February 2025 and a subsequent refocusing on medical technology.
Source
2022
Acquisition of Sound UnitedM&A
Background
Masimo sought to expand beyond hospital medical technology into consumer electronics, retail distribution, and connected-home experiences.
Action taken
Masimo acquired Sound United, adding audio brands including Bowers & Wilkins, Denon, Marantz, Polk Audio, Definitive Technology, Classé, and Boston Acoustics.
Aftermath
The acquisition expanded retail and engineering capabilities but also intensified investor debate over strategic focus and capital allocation.
Source
2022
Launch of the W1 Medical WatchProduct launch
Background
Masimo aimed to extend its monitoring technologies into wearable and consumer-facing formats.
Action taken
The company launched the W1 Medical Watch with continuous physiological-monitoring features and links to Masimo platforms.
Aftermath
The watch represented Masimo’s most visible move into medical wearables and connected consumer monitoring.
Source
2020
Launch of Masimo SafetyNetProduct launch
Background
The COVID-19 pandemic increased demand for remote monitoring, telehealth, and home-based clinical supervision.
Action taken
Masimo launched SafetyNet, linking compatible sensors, smartphones, and a cloud platform for remote patient monitoring.
Aftermath
The product established a clearer bridge between Masimo’s hospital monitoring technology and connected home care.
Source
2013
Introduction of the Root monitoring platformProduct launch
Background
Hospitals increasingly required monitoring systems that could combine multiple measurements and connect with software and third-party technologies.
Action taken
Masimo introduced Root as an expandable patient-monitoring and connectivity platform.
Aftermath
Root became a central platform for adding Masimo modalities such as SedLine, O3, and capnography.
Source
2005
Launch of rainbow Pulse CO-OximetryProduct launch
Background
Masimo sought to extend pulse oximetry beyond oxygen saturation and pulse rate into noninvasive estimation of additional blood constituents.
Action taken
The company introduced a multiwavelength platform supporting measurements such as total hemoglobin, carboxyhemoglobin, and methemoglobin on compatible devices.
Aftermath
The platform broadened Masimo’s identity from pulse-oximetry supplier to a broader noninvasive monitoring company.
Source

Recent events

2026
Danaher agrees to acquire Masimo[6]Danaher To Acquire Masimo Corporationinvestors.danaher.com
M&A
Danaher announced a definitive agreement to acquire Masimo for $180 per share in cash, representing an enterprise value of approximately $9.9 billion. Masimo was expected to remain a standalone operating company within Danaher’s Diagnostics segment.
2026
Masimo shareholders approve Danaher transaction[7]Masimo Shareholders Approve Acquisition by Danahermasimo.com
M&A
Masimo shareholders approved the merger agreement at a special meeting held May 1, 2026, clearing a major condition to Danaher’s acquisition.
2026
Danaher completes acquisition of Masimo[8]Danaher Completes Acquisition of Masimo Corporationmasimo.com
M&A
Danaher completed the acquisition on June 10, 2026. Masimo became a wholly owned subsidiary, its Nasdaq listing ended, and it continued operating under the Masimo brand.
2025
Masimo agrees to sell Sound United to Harman[11]Sound United sale is announcedmasimo.com
M&A
Masimo announced an agreement to sell its consumer-audio division, Sound United, to Harman International, a Samsung Electronics subsidiary, for approximately $350 million.
2025
Katie Szyman appointed Masimo chief executive officer[4]Masimo Leadership Transition Filingsec.gov
Leadership change
Masimo appointed Catherine Katie Szyman CEO effective February 12, 2025. Michelle Brennan moved from interim CEO to chair of the board.
2024
Masimo founder Joe Kiani leaves CEO role[3]Masimo Fiscal Year 2025 Form 10-K Amendmentsec.gov
Leadership change · Other
Joe Kiani resigned as Masimo’s CEO in September 2024 following a proxy contest involving activist investor Politan Capital Management.
2023
U.S. ITC finds Apple infringed Masimo pulse-oximetry patents[1]Masimoen.wikipedia.org
Lawsuit · Other
The U.S. International Trade Commission ruled that Apple infringed Masimo patents related to light-based pulse-oximetry technology used in Apple Watch products.
2023
Masimo receives FDA De Novo authorization for overdose-related respiratory-depression alert device[1]Masimoen.wikipedia.org
Product launch · Regulation
Masimo received FDA De Novo clearance for a pulse-oximetry-based device intended to alert users to respiratory depression as a potential early sign of opioid overdose.
2022
Masimo launches W1 Medical Watch[10]W1 Medical Watch launchessec.gov
Product launch · Product generation
Masimo introduced the W1 Medical Watch, extending its physiological-monitoring portfolio into a wearable format and linking consumer-facing monitoring with broader Masimo platforms.
2022
Masimo acquires Sound United[1]Masimoen.wikipedia.org
M&A
Masimo acquired Sound United, adding a substantial consumer-audio portfolio that included Bowers & Wilkins, Denon, Marantz, Polk Audio, Definitive Technology, Classé, and Boston Acoustics.

Sources22 sources

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