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

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

This marks the first time a US appeals court has ruled on a copyright dispute involving AI training, though the reasoning behind the decision remains confidential. Thomson Reuters, parent company of Reuters News, had accused Ross of copying Westlaw's "headnotes" - legal summaries extracted from court opinions - and using them to train its AI search engine to locate relevant legal opinions.

Ross shut down its platform in 2021 following the litigation costs imposed by Thomson Reuters. This case is distinct from others involving generative AI, as it does not involve the creation of new content, but rather the unauthorized use of copyrighted material to train AI systems. Ross had argued that its use of the headnotes was transformative, but the judge disagreed, stating that the company's use was not.