Apple has to pay Masimo another $184 million in interest on top of the $634 million jury verdict over Apple Watch heart-rate monitoring features. A federal judge ruled on the interest question on Monday, October 5.
Judge Selna issued the decision as per a report by Bloomberg Law. The interest pushes the total Apple owes Masimo to about $818 million.
Apple Lost Its Argument That Interest Would Hand Masimo a Windfall
Apple argued that adding interest would give Masimo more than it deserved. Selna rejected that. He pointed to US Supreme Court guidance that interest from the date royalties would have been paid “merely serves to make the patent owner whole.”
In patent cases, this kind of interest covers the gap between when payment should have started and when the court enters judgment. The longer that gap, the bigger the number gets. That is how a $634 million verdict ended up with a $184 million add-on.
Masimo asked for a 7% interest rate, and Selna denied it. He used Masimo’s own borrowing rate instead, compounded annually. The verdict was based on sales of Apple Watch models with heart-rate monitoring features.
Here is how the amounts stack up:
- Jury verdict in favor of Masimo: $634 million
- Interest added by Selna: $184 million
- Combined total: about $818 million
The Masimo Fight Over the Apple Watch Has Been Running Since January 2020
Masimo sued Apple in January 2020, and the jury verdict arrived in November 2025. The jury found that Apple Watch features such as high heart rate notifications infringed a Masimo patent. Apple said it would appeal, and argued that the patent expired in 2022 and covers patient monitoring technology from decades ago.
The two companies have clashed over the Apple Watch for years. Apple had to drop the blood oxygen feature to dodge an import ban, and a redesigned blood oxygen feature later returned in the US.
Masimo then sued US Customs over the Apple Watch oxygen feature, and US Customs challenged that lawsuit. Apple is dealing with other patent claims too, including a lawsuit from TrinamiX over Face ID skin detection patents.
Monday’s ruling added $184 million to a verdict that already stood at $634 million.
