Masimo vs. Apple Lawsuit: Import Ban, $634M Verdict, and Retrial

The Masimo vs. Apple lawsuit is a multi-front legal battle that began in January 2020 over the blood oxygen sensor in the Apple Watch. Masimo Corporation, a medical device maker, accuses Apple of stealing trade secrets and infringing patents tied to pulse oximetry technology. The fight has produced a U.S. import ban on certain Apple Watch models, a $634 million patent verdict against Apple, a countersuit by Apple over Masimo’s own smartwatch design, and a trade-secrets case still headed for retrial.

What Masimo Accused Apple of Doing

Masimo and its spinout Cercacor Laboratories sued Apple on January 9, 2020, in the Central District of California.1CourtListener. Masimo Corporation v. Apple Inc., 8:20-cv-00048 The core claim: Apple took trade secrets to build the Apple Watch’s light-based pulse oximetry feature, the sensor that estimates blood oxygen through the skin.

Masimo said Apple obtained those secrets by hiring away key employees. Internal Apple documents shown at trial referenced a 2013 initiative called “Project Everest” that listed an option for the “acquisition of Cercacor and/or Masimo (or people or assets).” Two of the most prominent recruits were engineer Marcelo Lamego and Michael O’Reilly, who joined Apple’s health team. Testimony revealed that Apple hired at least five additional Masimo and Cercacor employees between 2014 and 2020, and that internal Apple email threads carried the subject line “Recruiting from Masimo.”2Legal Affairs and Trials. Jury Learns of Other Masimo Hires Apple countered that the hires were coincidental and that the employees’ work at Apple was unrelated to the specific features at issue.

That first trade-secrets trial ended in mistrial in the spring of 2023. Masimo had sought up to $1.85 billion in damages, reduced from an original demand exceeding $3.1 billion. After three weeks of testimony, six jurors sided with Apple and one held out for Masimo, prompting Judge James V. Selna to declare a mistrial.3Fierce Biotech. Apple-Masimo Court Case Over Smartwatch Trade Secrets Ends Hung Jury

The Apple Watch Import Ban

While the California case moved forward, Masimo opened a second front. In June 2021, Masimo and Cercacor filed a complaint at the U.S. International Trade Commission, alleging that Apple Watch models with blood oxygen sensors infringed two Masimo patents (U.S. Patent Nos. 10,912,502 and 10,945,648) covering wearable devices that use LEDs and photodetectors to measure blood oxygen saturation.4U.S. International Trade Commission. Investigation No. 337-TA-1276, Notice of Final Determination

In October 2023, the Commission found that Apple violated Section 337 of the Tariff Act on five patent claims and issued a limited exclusion order barring the importation of Apple Watches with “light-based pulse oximetry functionality.”4U.S. International Trade Commission. Investigation No. 337-TA-1276, Notice of Final Determination The investigation focused on the Apple Watch Series 6 (introduced September 2020) and later models with the sensor.5Mintz. Federal Circuit Affirms ITC Exclusion Order Against Apple

The ban took effect December 26, 2023. Apple briefly halted sales of the Series 9 and Ultra 2, then got a federal appeals court to pause the ban the following day.6NBC News. Apple Can Use Redesign to Bypass Import Ban on Apple Watches, US Customs Says

Apple’s Redesign

To keep selling watches in the U.S., Apple disabled the pulse oximetry feature entirely and submitted the modified devices to U.S. Customs and Border Protection. In January 2024, CBP’s Exclusion Order Enforcement branch ruled that the modified watches fell outside the ITC’s exclusion order, clearing them for import.7PatentlyO. Apple Watch Pulse Oximetry Redesign Released

In August 2025, Apple reintroduced a redesigned blood oxygen feature through a software update for the Series 9, Series 10, and Ultra 2. The key change is that sensor data is now measured and calculated on a paired iPhone rather than on the watch itself, with results shown in the Health app.8Apple. An Update on Blood Oxygen for Apple Watch in the US CBP approved the updated version too.9Reuters. Apple Defeats Bid for New Apple Watch Import Ban at US Trade Tribunal

Masimo challenged the workaround. On March 18, 2026, an ITC administrative law judge issued a recommended determination finding that the redesigned version does not infringe Masimo’s patents.5Mintz. Federal Circuit Affirms ITC Exclusion Order Against Apple On April 22, 2026, the full Commission voted not to review that determination, effectively closing the enforcement case and letting Apple continue offering the blood oxygen feature to U.S. customers.10MedTech Dive. Apple Fends Off Masimo Challenge to Apple Watch Redesign

Federal Circuit Affirms the Ban

On March 19, 2026, the Federal Circuit issued its opinion in Apple Inc. v. International Trade Commission (No. 24-1285), affirming the ITC’s finding that Apple violated Section 337.11U.S. Court of Appeals for the Federal Circuit. Apple Inc. v. International Trade Commission, No. 24-1285 The court rejected every argument Apple raised, upholding the ITC’s conclusions on infringement, patent validity, claim construction, the domestic industry requirement, and prosecution laches.12IPWatchdog. Federal Circuit Affirms ITC Finding Apple Watch Infringes Masimo Blood Oxygen Patents

The practical effect: the original on-watch version of the blood oxygen feature remains barred from importation, while the iPhone-offloaded redesign is permitted.

The $634 Million Patent Verdict

In a separate case in California federal court, a jury awarded Masimo $634 million in November 2025 for patent infringement.13PatentlyO. Patient Consumer Wearable This case involved a different patent from the ITC dispute: U.S. Patent No. 10,433,776, covering low-power pulse oximetry designed to minimize battery drain in wearables.14Patsnap. Apple v. Masimo: Federal Circuit Affirms Patent Validity Its validity had already survived an Apple challenge at the Patent Trial and Appeal Board and a Federal Circuit appeal in January 2024.15U.S. Court of Appeals for the Federal Circuit. Apple Inc. v. Masimo Corporation, No. 22-1890

Apple moved in December 2025 to overturn the verdict or obtain a new trial, arguing that the jury’s award was unreasonable and that Apple had been “severely prejudiced” by erroneous court rulings.16Law360. Apple Seeks to Overturn $634M Masimo Patent Verdict Apple has said it will appeal if the motion fails.17Yahoo Finance. Apple Defeats Bid for Apple Watch Import Ban

Apple’s Countersuit Over Masimo’s Own Watch

The conflict also runs in the other direction. In 2022, Apple sued Masimo in Delaware federal court, alleging that Masimo’s W1 and Freedom smartwatches copied Apple Watch design patents.18Reuters. Masimo Smartwatches Infringe Apple Patents, US Jury Says Masimo called the suit retaliatory.

On October 25, 2024, a Delaware jury found that early versions of the W1 watch and its charger willfully infringed two Apple design patents. Apple was awarded $250, the statutory minimum for design patent infringement, a figure Apple itself had requested because the real objective was an injunction, not damages. The jury also found that Masimo’s current watches did not infringe, which Masimo called a win on the injunction question.18Reuters. Masimo Smartwatches Infringe Apple Patents, US Jury Says Apple moved in March 2025 for an injunction against the original W1 design.19Law360. Apple Seeks Ban Against Masimo’s Original Smartwatch

Trade-Secrets Retrial

The original trade-secrets case that ended in mistrial has continued toward retrial. Court docket records show a jury trial was scheduled before Judge Selna beginning November 4, 2025, following extensive pretrial activity including Daubert motions and summary judgment rulings.20CourtListener. Masimo Corporation v. Apple Inc., 8:20-cv-00048, Docket The case remained active as of mid-2026 with continuing pretrial filings.

The companies have not settled. Masimo CEO Joe Kiani said in December 2023 that he was “open to settling” and wanted to “work with them to improve their product,” but that Apple had not sought talks. “It takes two to tango,” he told Bloomberg.21Bloomberg. Masimo CEO Says He’d Settle Apple Watch Rift

Where the Fight Stands

As of mid-2026, the litigation looked like this: