Apple is being ordered to pay an extra $184 million to Masimo as part of the Apple Watch blood oxygen sensor trial, as an interest payment on top of the existing $634 million fine.
In November 2025, Masimo was awarded $634 million in compensation, after a federal jury agreed heart rate notification features and the Apple Watch workout mode violated its patents. Eleven months later, Apple has to pay even more.
An October 5 ruling by Federal Judge James Selina rejected an argument from Apple that adding interest to the existing award would be a windfall for Masimo, reports Bloomberg Law.
The judge cited guidance from the U.S. Supreme Court that the interest from the time that royalty payments would have been normally received "merely serves to make the patent holder whole."
In short, it's not a windfall, it's what Masimo was due, and now Apple has to pay it. The interest brings the total payments from Apple to Masimo up to $818 million.
It's not entirely bad news for Apple. It could've paid a lot more.
The judge rejected Masimo's demand for an intrest rate of 7%, and instead decided that the payment would be based on Masimo's own borrowing rate, compounding. If Masimo had its way, Apple would be paying $243 million in interest, an increase of $59 million.
A lengthy legal saga
Apple's courtroom activity with Masimo started back in 2020, over accusations that the Apple Watch infringed 10 patents and Apple's alleged stealing of trade secrets through hiring ikey personnel.
More lawsuits were filed in 2021 by Masimo, declaring that the Apple Watch Series 6 should be banned from sale for five patent infringements over blood oxygen measuring technology.
Lawfare continued in 2023, leading up to Apple preparing to stop sales of the Apple Watch at the end of that year to comply with an ITC ruling. However, after a temporary stay on December 27, 2023, it was determined that stripping out blood oxygen sensing in code would be enough to get around the ban.
The change allowed Apple to restore the feature to devices sold in the U.S. during the ban period, 18 months later.
Masimo was given its $634 million verdict in November 2025, with jurors agreeing that heart rate notification features and the Apple Watch's workout mode violated patents. The royalty figure was at the lower end of Masimo's requested range, but far higher than Apple's estimate of $3 million to $6 million.
By April 2026, Masimo's complaint over the USITC's decision to deny a reinstatement of the Apple Watch ban was dismissed with prejudice by a U.S. District Court. Not long after, in July 2026, Apple's attempt to appeal against the $634 million award was rejected.
