A federal judge on Monday ruled that Apple must pay an additional $184 million in interest. According to Sina Finance, the ruling stems from a $634 million jury award to Masimo Corp. over patent infringement involving the Apple Watch's heart-rate monitoring feature.

Judge James V. Selna rejected Apple's argument that awarding interest would give Masimo a windfall. He cited guidance from the U.S. Supreme Court, saying interest from the date a patent license fee should have been received is meant to restore the patent holder to the full economic position it would have had without infringement.

The judge did not accept Masimo's requested 7% rate and instead used Masimo's own borrowing rate from 2020, when the infringement began, with annual compounding. The U.S. District Court for the Central District of California also said Apple must continue paying post-judgment interest until the full judgment is satisfied, bringing the jury award plus prejudgment interest to $818 million.

The Monday hearing had been scheduled to consider Masimo's motions on prejudgment and post-judgment interest, but the docket showed Selna canceled it after both sides filed papers on his undated tentative ruling. The case stems from a 2025 trial in which the jury found that the Apple Watch's heart-rate alert feature infringed Masimo's U.S. Patent No. 10,433,776, which covers heart-rate and blood-oxygen monitoring technology. Selna had already denied Apple's request in July to vacate or reduce the award.