US appeals court upholds Thomson Reuters' landmark win in AI training lawsuit

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1. 1h ago

   Appeals Court Backs Thomson Reuters in AI Training Copyright Suit

   A US appeals court upheld a ruling for information services company Thomson Reuters on Tuesday in its copyright dispute with former legal research rival Ross Intelligence. The Philadelphia-based Third Circuit Court of Appeals backed Thomson Reuters in the landmark litigation concerning Ross's alleged misuse of copyrighted material, specifically Westlaw headnotes, to train an artificial intelligence-powered legal search engine. The case marks the first US appellate finding addressing fair use standards for artificial intelligence training, delivering a significant victory to copyright holders.

   Why it matters

   The litigation centers on how artificial intelligence companies utilize copyrighted works to train competitive products. The Third Circuit opinion maintains the win for Westlaw regarding the use of headnotes to train an artificial intelligence competitor.

   What is confirmed

   • A US appeals court on Tuesday upheld a ruling for information services company Thomson Reuters in its copyright dispute with former legal-research rival Ross Intelligence.
   • The dispute centers on Ross's alleged misuse of copyrighted material to train an AI-powered legal search engine.
   • The Philadelphia-based 3rd US Circuit Court of Appeals issued the opinion.

   Still unconfirmed

   • The 3rd Circuit opinion was initially sealed before being released.

   What to watch next

   • Further public availability or redaction details of the sealed 3rd Circuit opinion documents.
   • Potential subsequent legal appeals or further proceedings in the Thomson Reuters versus ROSS case.
   Sources used for this update (10)

   1. Reuters — US appeals court upholds Thomson Reuters' landmark win in AI training lawsuit
   2. lawnext.com — 3rd Circuit Issues Opinion in Thomson Reuters v. ROSS Case, But For Now It Is Sealed
   3. Copyright Lately — Signed, Sealed, Affirmed: Third Circuit Backs Thomson Reuters over ROSS
   4. Bloomberg Law News — Westlaw Retains Win Over Use of Headnotes to Train AI Competitor
   5. MLex — First US appellate finding on fair use for AI training favors copyright holders
   6. www.channelnewsasia.com — US appeals court upholds Thomson Reuters' landmark win in AI training lawsuit
   7. www.claimsjournal.com — Appeals Court Upholds Thomson Reuters’ Landmark Win in AI Training Lawsuit - Claims Journal
   8. www.aol.com — US appeals court upholds Thomson Reuters' landmark win in AI training lawsuit - AOL
   9. www.thestar.com.my — US appeals court upholds Thomson Reuters' landmark win in AI training lawsuit
   10. note.com — パテサロデイリー【昨日の英語知財ニュース】 2026年10月2日号｜パテントサロ....
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