Masimo Sues CBP Over Apple’s Blood Oxygen Readings on Watches

Medical technology firm Masimo has filed a lawsuit against the US Customs and Border Protection (CBP) over their decision to allow Apple to reinstate blood oxygen readings on its Apple Watches, bypassing a ban that was previously imposed.

In October 2023, the International Trade Commission (ITC) found that the Apple Watch Series 9 and Ultra 2 infringed upon Masimo’s patented light-based pulse oximetry technology, leading to a ban on their sale. However, Apple managed to reintroduce the feature by updating the software on its watches, allowing them to be sold once more.

Last week, blood oxygen readings reappeared on the Apple Watch Series 9, Series 10, and Ultra 2. Notably, these readings are now taken on an iPhone paired with the watch, rather than on the device itself. According to Apple’s announcement, this update was enabled by a recent US Customs ruling.

This development, however, has not been met favorably by Masimo. The lawsuit states that on August 1, 2025, CBP issued an ex parte ruling permitting Apple to import devices capable of performing the same functionality as the ITC found to infringe upon Masimo’s patents. Masimo claims it only became aware of this development after Apple made it public on Aug. 14.

In taking this action without involving Masimo, CBP is alleged to have exceeded its authority, acted unlawfully, and violated the company’s due process rights. As a result, Masimo is now seeking intervention from the US District Court for the District of Columbia to overturn CBP’s Aug. 1 ruling, which could potentially lead to the discontinuation of blood oxygen readings on Apple Watches once more.

“Each passing day that this unlawful ruling remains in effect unfairly deprives Masimo of its right to be shielded from unfair trade practices and to maintain its competitive position in the US market,” stated Masimo in a public statement.