US appeals court upholds Thomson Reuters' landmark win in AI training lawsuit

On Tuesday, a US appeals court affirmed a decision in favor of information services firm Thomson Reuters in a copyright lawsuit against former rival Ross Intelligence. The Philadelphia-based 3rd US Circuit Court of Appeals rejected Ross's claim that its AI-powered legal search engine had made fair use of material from Thomson Reuters' Westlaw platform.

This marks the first instance of a US appeals court ruling on a copyright case involving AI training. The specifics of the court's reasoning remain undisclosed. Ross' spokesperson and an attorney have not yet commented on the decision. Thomson Reuters expressed satisfaction with the ruling, emphasizing the importance of respecting copyright for innovation and protecting intellectual property that drives AI solutions.

The lawsuit alleged that Ross had copied Westlaw's headnotes, which summarize legal points, and used them to train its AI-based legal search engine, which identified relevant court opinions for user queries. Ross ceased operations in 2021 due to the litigation costs. This case is unique as it does not involve generative AI, which creates new content, and involves copyright disputes over AI training for the first time in a US appeals court.