Masimo takes CBP to court for approving Apple Watch imports with patent-infringing blood-oxygen function

Masimo Corporation, the American medical-technology company, has taken legal action against U.S. Customs and Border Protection in Washington, D.C., after the agency allowed Apple Inc. to continue importing Apple Watch models with blood-oxygen monitoring despite a long-running patent dispute. The case shines a spotlight on how trade enforcement interacts with intellectual property rights at the intersection of health-tech and consumer electronics.

According to Masimo’s filing, Customs reversed its earlier stance that upheld an International Trade Commission (ITC) exclusion order banning Apple Watch Series 9 and Ultra 2 models using Masimo’s patented pulse-oximetry technology. The ITC had previously determined in 2023 that Apple infringed Masimo’s intellectual property, prompting the import ban. But on August 1, Customs permitted Apple to bring in new watches with a software workaround that re-enabled the disputed feature. Masimo says this reversal undermines ITC enforcement and bypasses due process.

Industry observers note that the court’s handling of this case could reset expectations for patent holders in enforcing ITC bans, especially as consumer technology increasingly overlaps with regulated health functions.

What led Masimo to escalate its patent enforcement against Apple and now sue U.S. Customs?

Masimo has accused Apple for years of misappropriating its proprietary blood-oxygen sensor designs and hiring away its engineers to replicate key technology. The ITC decision in late 2023 vindicated part of this claim, resulting in an exclusion order that barred the import of affected Apple Watch models.

To comply, Apple disabled the blood-oxygen monitoring feature through software updates, allowing continued sales of hardware but without the contested functionality. For several months, Apple marketed U.S. models without the feature, while international versions retained it.

On August 14, Apple announced that it would reintroduce blood-oxygen measurement via a new software update. The change reroutes data processing from the watch to a paired iPhone, a modification Apple claimed complied with U.S. government approval. Masimo’s lawsuit argues that Customs’ acceptance of this workaround effectively nullified the ITC ruling and denied Masimo the ability to defend its rights.

Why is Masimo objecting to Customs’ approval of Apple’s workaround in the blood-oxygen feature dispute?

In its complaint, Masimo asserted that Customs’ decision on August 1 was made without notifying or consulting the medical-technology firm. The company argues this action violated administrative law and the Fifth Amendment’s due-process protections. By allowing Apple to activate blood-oxygen measurement again, Masimo claims Customs effectively acted as a final authority in a dispute already adjudicated by the ITC.

The medical-technology company emphasized that each day of delay in restoring the ITC exclusion order inflicts market harm, erodes competitive advantage, and reduces confidence in the enforceability of U.S. patent protections. Masimo is seeking both a temporary restraining order and a preliminary injunction to block Customs’ ruling while the case proceeds.

How are Apple, investors, and institutional stakeholders reacting to Masimo’s lawsuit against Customs?

Apple has not issued a direct response to the lawsuit. In prior statements, the Cupertino-based technology company defended its software workaround, claiming it complied with U.S. law and maintained a seamless experience for Apple Watch users.

Institutional investors have reacted cautiously. Shares of Masimo Corporation (NASDAQ: MASI) gained modestly after the lawsuit was announced, reflecting optimism among some investors that stronger patent enforcement could support its intellectual-property portfolio. At the same time, Apple’s stock (NASDAQ: AAPL) remained stable, reflecting the broader scale of its business where Apple Watch sales are significant but not dominant compared to iPhone and services revenue.

Analysts say institutional sentiment is divided. Some view Masimo’s assertiveness as an important test case for strengthening patent enforcement mechanisms in U.S. trade law, while others warn that protracted litigation may not deliver significant financial benefit relative to the costs. For Apple, the risk is reputational as much as commercial: repeated disputes over health-related technology highlight the company’s reliance on contested innovation pathways.

What could be the market and legal implications if Masimo prevails in reinstating the import ban?

If the court rules in favor of Masimo, Customs may be required to withdraw approval of Apple’s workaround, which could force Apple to once again disable or remove the blood-oxygen feature in U.S. Apple Watch models. That would strengthen the ITC’s role as a decisive arbiter in patent enforcement and provide reassurance to intellectual-property holders that exclusion orders remain durable.

For Masimo, a favorable outcome could bolster its negotiating leverage against large technology firms and reaffirm its competitive stance in non-invasive monitoring. For Apple, an adverse ruling could delay rollout of health-related watch features in its upcoming Series 10, adding uncertainty around regulatory pathways for future product launches.

On the other hand, if the court sides with Customs and Apple, the precedent could grant technology firms more flexibility to implement workarounds during disputes. That could weaken the deterrent power of ITC bans and complicate enforcement for smaller innovators whose patents are infringed.

How does this lawsuit reflect the evolving balance of power between patent holders and multinational technology firms?

The dispute underscores a broader trend in which medical-technology innovators are clashing with consumer-tech giants over ownership of health-related features. The Apple-Masimo battle has become emblematic of the difficulties smaller firms face when defending intellectual property against multinational companies with deep resources.

Patent enforcement via ITC exclusion orders has traditionally been a powerful tool for leveling the playing field. But if Customs or courts dilute that authority, critics argue it could discourage innovation among smaller medical-technology companies and embolden large corporations to pursue aggressive design-around strategies.

For global investors, the case is being closely watched as a test of how U.S. agencies reconcile innovation, consumer choice, and intellectual-property enforcement in one of the fastest-growing sectors: wearable health technology.

What is the forward-looking outlook as Masimo’s legal challenge against Customs progresses?

The case is still in its early stages, but analysts expect initial rulings on Masimo’s request for a restraining order in the coming weeks. Institutional investors are likely to monitor court signals to gauge whether stricter enforcement could impact Apple Watch availability in the U.S.

For Masimo, the lawsuit carries reputational stakes as it positions itself as a defender of intellectual property in the face of industry giants. A win could elevate the company’s standing with both investors and potential partners. For Apple, the proceedings highlight the risks that come with embedding regulated health features into consumer devices, especially when those features draw on contested innovations.

Over the long term, the outcome could shape how companies balance health-tech development with the legal and procedural hurdles of patent enforcement. Whatever the court decides, the Masimo–Customs dispute will serve as a precedent for future clashes between technology companies and U.S. regulators.