2026-09-30——
Third Circuit affirms Thomson Reuters win against ROSS Intelligence over Westlaw headnote AI training
A short entry: a summary of the public record, checked against its sources, not yet read and analysed by Gianluca. How the register works
On 30 September 2026 the Third Circuit affirmed a district court ruling that ROSS Intelligence infringed Thomson Reuters' copyright by training its AI legal research tool on Westlaw headnotes, rejecting ROSS's fair use defense.
What happened
- Thomson Reuters sued ROSS Intelligence in May 2020 after ROSS used third party LegalEase Solutions to access Westlaw headnotes following Westlaw's refusal to license ROSS directly.
- In February 2025, Judge Stephanos Bibas granted Thomson Reuters partial summary judgment, finding ROSS infringed 2,243 Westlaw headnotes.
- The Third Circuit panel heard oral argument on 11 June 2026 and affirmed on 30 September 2026, with Judge Tamika Montgomery-Reeves writing the opinion joined by Judges L. Felipe Restrepo and Emil J. Bove III.
- The panel held Westlaw's headnotes showed the 'creative spark' required for originality and that ROSS's use was 'minimally transformative at best'.
- The panel found harm to Westlaw in both the legal research market and the derivative market for licensing headnotes to train AI.
- ROSS Intelligence went defunct in January 2021 citing litigation costs; counsel Yar Chaikovsky of White & Case said ROSS will seek Supreme Court review.
Who is involved
Thomson Reuters
Thomson Reuters is an AI and technology company empowering professionals with trusted content and workflow automation.
ROSS Intelligence
ROSS Intelligence builds AI-driven products to augment lawyers' cognitive abilities.
Sources
- courthousenews.com — primary
- techtimes.com — corroborating
- claimsjournal.com — party background
- en.wikipedia.org — party background
- legaltechnology.com — party background
- copyrightlately.com — party background
Announced 2026-09-30