Apple’s request to overturn a $634 million patent judgment and secure a new trial in its long-running legal battle with Masimo has been denied. Here are the details:
a little background
In early 2020, medical technology company Masimo sued Apple for stealing trade secrets and infringing patents related to pulse oximetry and other optical health monitoring technologies used in the Apple Watch.
Since then, the two companies have been embroiled in a major legal battle. In 2023, Masimo secured an International Trade Commission (ITC) ruling that led to a U.S. import ban affecting Apple Watch models equipped with blood oxygen monitoring.
In response, Apple temporarily suspended sales, then resumed sales of the affected models with the blood oxygen feature disabled. In 2025, the company introduced a redesigned feature that measures and calculates sensor data from the Apple Watch on a paired iPhone and displays the results in the Health app. Masimo subsequently sued U.S. Customs and Border Protection over its decision to allow import of the redesigned watch.
Meanwhile, the patent portion of Masimo’s original California lawsuit was tried separately from the ITC lawsuit. In November 2025, a jury found that the Apple Watch’s heart rate monitoring and notification features infringed another Masimo pulse oximetry patent and ordered Apple to pay $634 million in damages.
Since then, Apple has continued to try to reverse this finding, to this day.
the judge upholds the jury’s findings
According to reports law 360 (via AppleInsider):
Apple lost its bid to avoid a jury finding it owed $634 million for infringing Masimo’s patents after a federal judge in California rejected the tech giant’s challenge to how the court interpreted key terms and made a bid for a new trial.
U.S. District Judge James V. Serna denied Apple’s request for judgment as a matter of law or a new trial in the multi-pronged lawsuit, rejecting one of Apple’s arguments that its product is not a “patient monitor” as required by Masimo’s patent.
In his ruling, Judge Serna upheld the jury’s conclusion that the Apple Watch could be considered a patented patient monitoring device. Apple essentially argued that the term should only apply to traditional medical devices, but the judge ruled that the patent’s broader, everyday meaning could also apply to the Apple Watch.
He also rejected Apple’s request for a new trial. Apple challenged the jury instructions and the decision to exclude the testimony of one of its experts, but Judge Serna found there were no errors significant enough to warrant a new trial.
When asked for comment, Apple referred Law360 to its previous statement:
“Masimo is a medical device company that does not sell any products to consumers. Over the past six years, they have sued Apple in multiple courts and asserted more than 25 patents, most of which were found to be invalid. (…) The single patent in this case expires in 2022 and is specific to historic patient monitoring technology that is decades old. We plan to appeal.”
To read Law360’s full report, click this link.
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