• by Wendy Davis , Yesterday

A federal appellate court on Tuesday upheld a ruling that artificial intelligence company Ross Intelligence infringed copyright by training its legal research service on material owned by Thomson Reuters' Westlaw.

The decision appears to mark the first time an appellate court has weighed in on whether artificial intelligence companies are entitled to train their platforms on other publishers' content.

The opinion, issued by a three-judge panel of the Third Circuit Court of Appeals, is temporarily sealed.

The ruling comes in a battle dating to 2020, when Thomson Reuters sued Ross for allegedly training its legal research platform on Westlaw "headnotes" -- summaries of key points in judicial opinions.

Thomson Reuters alleged that Ross “surreptitiously” obtained Westlaw's headnotes from a licensee, then drew on them to “rush out a competing product without having to spend the resources, creative energy, and time to create it itself.”

Ross argued the matter should be dismissed for several reasons, including that it was protected by fair use principles.

In February 2025, U.S. District Court Judge Stephanos Bibas sided against Ross, ruling that the company was not entitled to a fair-use defense because it used Westlaw's headnotes for the same purpose as Thomson Reuters, and aimed to compete with it.

Ross then appealed that ruling to the Third Circuit, and tech organizations as well as digital rights groups backed the artificial intelligence company.

NetChoice and other tech groups argued in a friend-of-the-court brief that Ross's use of the headnotes was transformative because the headnotes enabled Ross to create a new natural language legal search engine.

Entertainment and publishing organizations sided with Westlaw in friend-of-the-court briefs.

Disney and other studios contended in their filing that a ruling in favor of Ross would "chill incentives to continue investing in and creating the movies and television shows that delight audiences worldwide and fuel the engine of the American entertainment industry."

The Third Circuit is expected to unseal the opinion after it issues a decision on requests by the parties to keep certain information confidential.