Apple's Patent Bill Grows to $818 Million as Court Adds $184 Million in Interest: What This Means for Patent Holders

A federal judge ruled on October 6, 2026, that Apple must pay an additional $184 million in prejudgment interest on top of the $634 million patent infringement verdict awarded to medical technology company Masimo Corporation, bringing Apple's total bill in the case to approximately $818 million. U.S. District Judge James Selna issued the ruling in what has become one of the most expensive patent disputes in recent years. For patent holders and businesses developing technology-driven products, the case illustrates the full scope of financial consequences that follow a finding of infringement.

The Dispute

Masimo, a nearly 40-year-old medical technology company based in Irvine, California, sued Apple over a pulse-oximetry patent that covers technology used in the Apple Watch's health monitoring features. The dispute has been ongoing for several years, with Masimo alleging that Apple incorporated its patented technology into the Apple Watch without obtaining a license. In November 2025, a jury found Apple liable for patent infringement and awarded Masimo $634 million in damages. Apple attempted to overturn the verdict, but Judge Selna upheld the jury's decision in July 2026.

The October 2026 ruling addressed the question of prejudgment interest, which compensates a patent holder for the time value of money lost between the date infringement began and the date of the verdict. Judge Selna stated that "interest from the time that the royalty payments would have been received merely serves to make the patent owner whole." He rejected Apple's argument that the interest award would be a windfall for Masimo and declined Masimo's request for a 7% interest rate, instead applying Masimo's actual borrowing rate to calculate the $184 million figure. Post-judgment interest continues to accrue until Apple makes full payment. Separately, Masimo also obtained a U.S. International Trade Commission import ban on certain Apple Watch models, which prompted Apple to disable blood oxygen features on affected devices.

Why This Ruling Matters

This case demonstrates that patent infringement damages extend well beyond the initial jury verdict. Prejudgment interest is a standard remedy in patent cases, designed to ensure that a patent holder receives the full economic value of the rights that were violated. Without interest, an infringer would effectively benefit from delaying payment, keeping money that rightfully belongs to the patent holder. Courts routinely award prejudgment interest to place the patent owner in the position it would have occupied had the infringer paid a reasonable royalty at the time of infringement rather than forcing the patent holder to litigate for years to recover what it was owed.

The Masimo patent expired in June 2022, but expiration does not eliminate liability for past infringement. A patent holder can pursue damages for any infringement that occurred during the life of the patent, even after the patent itself is no longer in force. This is an important point for businesses that assume they can simply wait out a patent's term to avoid consequences.

Key Takeaway for Business Owners

This ruling serves as a strong reminder that patent infringement carries compounding costs. The longer a dispute takes to resolve, the more interest accrues on any damages award. Businesses that develop products incorporating third-party technology should invest in thorough patent clearance searches before bringing products to market. Identifying potential patent conflicts early and negotiating licensing agreements is almost always less expensive than facing a jury verdict plus years of accumulated interest. For patent holders, this case reaffirms that enforcing patent rights can yield significant returns, including interest that compensates for the delay between infringement and recovery.

Whether you are building a patent portfolio, evaluating potential infringement risks, or considering enforcement of your existing patents, having a clear strategy is essential. Schedule a free consultation with Diorio IP Law Group to discuss how to protect your innovations and maximize the value of your intellectual property.