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.
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 · Added to the register 2026-10-02