A jury must decide the outcome of a lawsuit by information services company Thomson Reuters accusing Ross Intelligence of unlawfully copying content from its legal-research platform Westlaw to train a competing artificial intelligence-based platform, a Delaware federal judge said on Monday.

The decision by U.S. Circuit Judge Stephanos Bibas sets the stage for what could be one of the first trials related to the unauthorized use of data to train AI systems. Tech companies including Meta Platforms, Stability AI and Microsoft-backed OpenAI are also facing lawsuits from authors, visual artists and other copyright owners over the use of their work to train the companies' generative AI software.

A spokesperson for Thomson Reuters, the parent company of Reuters News, said it looks forward to presenting evidence to a jury.

"This case continues to be about Ross’ theft of Thomson Reuters proprietary commentary, analysis, and organizational system," the spokesperson said. "We sought summary judgment on select issues because we believe the facts of the case are clear cut."

Representatives for Ross did not immediately respond to requests for comment.

Thomson Reuters' 2020 lawsuit accused legal research company Ross Intelligence of copying Westlaw's "headnotes," which summarize points of law in court opinions. Thomson Reuters accused Ross of misusing thousands of the headnotes to train its AI-based legal search engine.

Ross said it shut down its platform in January 2021, citing the costs of the "spurious" litigation. Reuters could not establish if it did so.

Both companies asked the court for pretrial wins in the case. Ross argued in part that it made fair use of the Westlaw material, raising what could be a pivotal question for legal disputes over generative AI training.

Ross said that the Headnotes material was used as a "means to locate judicial opinions," and that the company did not compete in the market for the materials themselves. Thomson Reuters responded that Ross copied the materials to build a direct Westlaw competitor.

Bibas said on Monday that a jury should decide fair use and other questions, including the extent of Thomson Reuters' copyright protection in the headnotes. He noted that there were factors in the fair-use analysis that favored each side.

The judge said he could not determine whether Ross "transformed" the Westlaw material into a "brand-new research platform that serves a different purpose," which is often a key fair use question.

Bibas also said he could not decide whether a ruling for Ross or Thomson Reuters would best serve the public interest.

"Here, we run into a hotly debated question," Bibas said. "Is it in the public benefit to allow AI to be trained with copyrighted material?"

No trial date has been set in the case.