The U.S. Court of Appeals for the Third Circuit upheld the ruling against ROSS Intelligence in a dispute with Thomson Reuters concerning the use of copyrighted content to train an artificial intelligence system.
The case concerned ROSS Intelligence’s use of legal headnotes from Westlaw, a legal research database owned by Thomson Reuters, to develop a competing AI-powered legal research tool.
The court held that the headnotes at issue were protected by copyright and that ROSS Intelligence’s use of them was not covered by the U.S. fair use doctrine. Among other factors, the court considered the commercial purpose of the use, its limited transformative nature, and its impact on the existing and potential markets for the copyrighted content.
The decision, issued on 29 September 2026, marks a significant development in U.S. case law concerning copyright and the training of artificial intelligence systems. It should be noted, however, that the case concerned a legal research system rather than generative AI. Accordingly, the decision does not constitute a general ruling on the legality of using copyrighted works to train all types of artificial intelligence systems.
Source: U.S. Court of Appeals for the Third Circuit, Thomson Reuters Enterprise Centre GmbH v. ROSS Intelligence Inc., No. 25-2153 (2026).
Read the decision here.