Apple’s $634 Million Masimo Patent Judgment Grows to About $818.5 Million With Interest

On November 14, 2025, a federal jury found that Apple infringed claims 11 through 14 of Masimo’s U.S. Patent No. 10,433,776. On July 20, 2026, Judge Selna entered final judgment awarding Masimo $634,313,913 in patent damages and concluded that Apple’s infringement was not willful.

The July judgment expressly reserved prejudgment and postjudgment interest for later determination. The additional $184.2 million was therefore not a second jury verdict and not an enhanced award for willful infringement. It was an interest award.

Federal patent law provides that a successful claimant may receive damages adequate to compensate for infringement, “together with interest and costs as fixed by the court.” See 35 U.S.C. § 284.

In General Motors Corp. v. Devex Corp., 461 U.S. 648, 655–57 (1983), the U.S. Supreme Court explained that prejudgment interest serves to place the patent owner in about the position it would have occupied had royalty payments been made when due, and held that it should ordinarily be awarded absent some justification for withholding it. Money that should have been paid years earlier has economic value during the time it was unavailable.

The parties disagreed sharply over the calculation. According to Bloomberg Law and MedTech Dive’s reporting on the October 5 order:

The choice of rate changed the result by tens of millions of dollars—a reminder that interest is a meaningful part of damages analysis, not an afterthought.

Prejudgment interest addresses the period before judgment—here, the time during which royalty-related money would otherwise have been available to Masimo. Postjudgment interest begins after judgment and can continue while a federal money judgment remains unpaid. It is governed by 28 U.S.C. § 1961.

Reporting states that Judge Selna applied a 4% postjudgment rate to the approximately $818.5 million amount, running from July 20, 2026, until the judgment is satisfied. The amount associated with the judgment can therefore continue to grow, subject to further proceedings.

The court found Apple’s infringement not willful, yet still awarded substantial prejudgment interest. That is because the two remedies serve different purposes: interest compensates for delayed payment, while enhanced patent damages involve different considerations, such as particularly culpable infringement. The October award should not be described as additional punishment.

The July judgment also found that Apple misappropriated two identified Masimo trade secrets, but awarded no monetary relief on those claims. The $634.3 million award and the interest discussed here belong to the patent-infringement judgment, not the trade-secret findings.

When litigation lasts for years, parties may need to weigh not only:

but also whether applicable law permits prejudgment or postjudgment interest. The rules vary by claim. This federal patent framework should not be treated as a universal rule for California contract, tort, property, or other commercial disputes.

Interest is one of several categories that separate winning a case from what is ultimately recovered; see also why winning a California lawsuit does not automatically mean recovering attorney fees.

The July 2026 judgment awarded approximately $634.3 million in patent damages. The October ruling added approximately $184.2 million in prejudgment interest, bringing the total to roughly $818.5 million before continuing postjudgment interest. It was not another jury award and not a finding of additional misconduct, and the ruling remains subject to further proceedings. For businesses evaluating significant litigation, the headline damages figure may not tell the entire financial story.

Mahrouyan Law, P.C. handles selected intellectual-property matters and business and commercial litigation, and advises founders on intellectual-property ownership, licensing, and startup risk. Specialized patent matters may require patent counsel or appropriate co-counsel depending on the circumstances.