Thomson Reuters blasts appeal in dispute over Westlaw copying
2025 IPDBRF 4324
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WESTLAW Intellectual Property Daily Briefing
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November 20, 2025
(November 20, 2025) – Thomson Reuters has filed a response to ROSS Intelligence Inc.’s claim that copying Westlaw content was permissible for training its artificial intelligence system, saying the dispute differs from others involving AI training.
Thomson Reuters Enterprise Centre GmbH et al. v. ROSS Intelligence Inc., No. 25-2153, appellees’ brief filed (3d Cir. Nov. 19, 2025).
ROSS’ arguments fail to show that its actions were permitted under U.S. copyright law, Thomson Reuters Enterprise Centre GmbH and its West Publishing Corp. subsidiary say in their brief, filed Nov. 19 with the 3rd U.S. Circuit Court of Appeals.
ROSS does not dispute that it copied Westlaw content, including more than 2,000 headnotes. Rather, it claims that the content was not copyrightable.
While judicial opinions are generally not protected by copyright law, Thomson Reuters notes that Westlaw’s “original selection and arrangement” of legal materials have been recognized by the U.S. Copyright Office, which registers the materials.
Writing the headnotes involves creative choices about wording and context, the brief says, arguing that headnotes “easily pass the bar required for copyright protection.”
Brief claims no fair use here, maybe elsewhere
Assuming the works in question are copyrightable, ROSS says its actions were nevertheless permitted under the fair-use doctrine.
U.S. Circuit Judge Stephanos Bibas, sitting by designation in the U.S. District Court for the District of Delaware, rejected this argument. Thomson Reuters Enter. Ctr. GmbH v. ROSS Intel. Inc., 765 F. Supp. 3d 382 (D. Del. 2025).
The appellees’ brief points out that Judge Bibas’ decision, addressing whether training an AI system can be considered a fair use, applies only to the copying of Westlaw content.
“This is not a generative AI case,” the brief says, cautioning the 3rd Circuit not to address “all scenarios” in which an AI company has used copyrighted content.
“There may be factual circumstances where such copying is a fair use,” the brief says. “This scenario — where the copying was for purposes of creating a commercial substitute for the original — is not one of them.”
Considering the factors courts use to decide if a use is fair, Thomson Reuters says the “most important factor,” which measures a use’s effect on “actual” or “potential” markets, fell against ROSS precisely because its product is a commercial substitute for Westlaw content.
The brief includes an advertisement that compares ROSS’ services to Westlaw’s and states that some Westlaw customers switched providers.
The appellees also downplay ROSS’ comparison of its services to Google’s book-scanning initiative, which the 2nd U.S. Circuit Court of Appeals ruled was largely permissible as a fair use. Authors Guild Inc. v. Google Inc., 804 F.3d 202 (2d Cir. 2015).
“That case involved a tool that provided searchers access to small, arbitrarily distributed snippets of books that were unlikely to substitute for the original books and actually helped customers find the original books,” the brief says. “Here, customers are not directed to the original; they are being pitched to purchase ROSS instead of Westlaw.”
‘Not technological advancement’
The appellees also discount the argument that headnotes were not a “substantial part” of the training data, further distancing the dispute over Westlaw content from other generative AI training controversies.
Other AI training disputes involve scraping large amounts of data from the internet, a small piece of which can be used for training data sets. “There is no evidence that ROSS trained on anything other than [infringing content],” the brief says.
Those other AI firms might be able to argue that their systems benefit the public with new creations, the appellees say.
Given the circumstances, ROSS cannot claim its system, as a competitor to Westlaw, can accomplish what those AI firms can, the brief says.
“ROSS’ copying was not technological advancement,” Thomson Reuters says. “It was theft.”
West Publishing operates the Westlaw legal research service. Thomson Reuters publishes Westlaw Journals and Westlaw Daily Briefings.
Attorneys from Kirkland & Ellis LLP represent Thomson Reuters and West. Attorneys from Pillsbury Winthrop Shaw Pittman LLP and White & Case LLP represent ROSS.
