CopyrightU.S. appeals court rules a legal-research AI's training on case summaries was not fair use

The U.S. Court of Appeals for the Third Circuit on September 30 upheld the lower court in Thomson Reuters' copyright suit against the legal research startup ROSS. ROSS copied thousands of Westlaw headnotes to train its legal search AI, and the court found that this was not fair use. It called the use commercial and a competing product, only minimally transformative at best, and harmful to both the Westlaw market and the market for licensing AI training data.

ROSS first asked Thomson Reuters for a license and was refused, then had a third party build training material. ROSS's lawyer said the company intends to seek Supreme Court review.