Zunum Aero v. Boeing — Ninth Circuit Keeps Trade-Secret Appeal and Rejects Patent-Jurisdiction Challenge

Background

Zunum Aero accused Boeing of misusing confidential hybrid-electric-aircraft technology obtained through their investment relationship. Zunum brought Washington-law claims including trade-secret misappropriation, breach of contract, and interference with a business expectancy. Boeing responded with federal counterclaims seeking declarations that its personnel were the sole inventors of two patents, then removed the dispute to federal court.

A jury found that Boeing misappropriated 11 trade secrets and awarded substantial damages, but the district court set the verdict aside and conditionally ordered a new trial. In 2025, a Ninth Circuit panel reversed those post-trial rulings. Boeing sought rehearing and argued for the first time that the Federal Circuit had exclusive appellate jurisdiction because Boeing’s patent-inventorship counterclaims were compulsory.

The Court’s Holding

The published rehearing order rejected Boeing’s jurisdictional argument. Although the inventorship counterclaims arose under federal patent law, they were permissive rather than compulsory. Zunum relied on many alleged trade secrets and multiple theories of misuse; references to Boeing’s patents were only part of that broader case. The facts needed to prove Zunum’s misappropriation claim therefore did not sufficiently overlap with the facts Boeing needed to establish sole inventorship.

That conclusion left appellate jurisdiction in the Ninth Circuit rather than the Federal Circuit. The panel also rejected Boeing’s fallback argument that a permissive federal counterclaim could not support supplemental jurisdiction over the state-law claims. Joining the other circuits to address the issue, it held that the tests are different: claims can share the common nucleus of operative fact required for supplemental jurisdiction even when they do not arise from the same transaction or occurrence for compulsory-counterclaim purposes. Boeing’s access to and alleged misuse of Zunum’s confidential aircraft technology supplied that common nucleus.

Judge Bade agreed that the counterclaims were permissive and that rehearing should be denied, but would have applied a more transaction-focused analysis rather than the majority’s broader “logical relationship” formulation.

Key Takeaways

• A patent counterclaim does not automatically route an appeal to the Federal Circuit; exclusive jurisdiction depends on whether the counterclaim is compulsory.
• The compulsory-counterclaim test is narrower than the constitutional “same case or controversy” standard used for supplemental jurisdiction.
• Using a patent as one item of evidence in a much broader trade-secret case does not necessarily make inventorship part of the same transaction.

Why It Matters

Technology disputes often mix state trade-secret theories with federal patent claims. This order gives parties a clearer map for determining both the proper appellate court and whether the federal forum may keep the full dispute. It also prevents a late jurisdictional objection from displacing the Ninth Circuit’s earlier restoration of Zunum’s trade-secret verdict merely because related patents appeared in the case.