Apple owes Masimo $184 million in interest on the Apple Watch patent verdict, taking the bill to about $818 millionApple owes Masimo $184 million in interest on the Apple Watch patent verdict, taking the bill to about $818 million

A federal judge in California has ordered Apple to pay Masimo $184 million in interest on top of the $634 million a jury awarded the medical device maker over the Apple Watch.

Judge James Selna of the US District Court for the Central District of California issued the ruling on 5 October, Bloomberg Law first reported, and Law360 reported the same figure separately. With the interest added, Apple's bill comes to about $818 million. That still leaves out post-judgment interest, which keeps running until Apple actually pays, MacRumors notes.

The underlying verdict dates from November 2025, when a jury found that Apple Watch features including heart rate notifications infringed Masimo's US patent 10,433,776. Selna entered final judgment for $634,313,913 on 23 July 2026, Strata-gee reported at the time, and put off the interest question until both sides had argued it.

How did the judge arrive at $184 million?

Apple argued that adding prejudgment interest would hand Masimo a windfall. Selna disagreed, citing US Supreme Court guidance that such interest only makes a patent owner whole: it pays for the years Masimo went without the royalties it should have received while the infringement went on.

Masimo did not get everything it asked for. It wanted interest at 7 per cent, which would have produced about $243 million. Selna instead used Masimo's own borrowing rate, compounded every year from the start of the infringement. That choice alone is worth $59 million to Apple, by AppleInsider's arithmetic.

Does this affect the Apple Watch you can buy today?

No. The patent expired in June 2022, MacRumors reports, so the case is about past sales only. Heart rate notifications on current models are untouched. This is also a different dispute from the one that led to the US import ban and to Apple switching off blood oxygen readings on watches sold during it. That feature came back in a redesigned form in 2025.

Our take

The headline number is the interest, but the more telling figure is the gap the jury had to bridge. AppleInsider reports that Apple's own damages estimate at trial was $3 million to $6 million. A verdict two orders of magnitude above that, upheld, and now grown by nearly a third through interest alone, is the cost of taking a patent fight to the end and losing. Interest compounds against whoever is losing for longer, and this case has been running since 2020.

It is also part of a pattern this year. A jury ordered Apple to pay 5.7 billion dollars over Taptic Engine patents in the Taction case, and Apple's own trade secret case against Oppo over the Apple Watch is going ahead. The watch has become one of Apple's most litigated products, in both directions.

What none of the reports settles is when, or whether, Apple pays. An appeal was filed on the day the July judgment was entered, Strata-gee reported, and Apple has fought every stage so far. APPDOOK expects the $818 million to sit under appeal for a long time, with post-judgment interest adding to it the whole while. For Apple Watch owners nothing changes. For Apple, the cheapest moment to settle this passed several years ago.