TL;DR
The Third Circuit has issued the first U.S. appellate ruling on AI training and fair use, affirming that Ross Intelligence infringed Thomson Reuters' Westlaw headnotes, and setting a precedent that could reshape how AI companies source training data.
What happened
- The Third Circuit Court of Appeals upheld Thomson Reuters' copyright victory against Ross Intelligence on September 30, 2026.
- Ross Intelligence used Westlaw headnotes (curated legal summaries written by Thomson Reuters editors) to train a competing AI-powered legal research platform.
- The court framed the case not as a novel AI question but as an "ordinary copyright case," rejecting Ross's fair use defense.
- This is the first U.S. appellate ruling to directly address whether scraping copyrighted material for AI training qualifies as fair use.
- The decision affirms a lower court ruling that had already found in Thomson Reuters' favor.
Why it matters
- Fair use as an AI training shield is now weaker: the highest appellate court to rule on the question has said no, at least where the training data competes directly with the source product.
- AI companies that scraped commercial, curated datasets (not raw public-domain text) face the greatest immediate exposure from this ruling.
- Legal tech is the first sector to feel the impact, but the logic applies broadly: any AI product trained on proprietary data to build a competing service is now on notice.
- Thomson Reuters gains significant leverage in licensing negotiations with AI developers who want access to Westlaw content.
- The ruling creates a circuit-level precedent that other courts will cite, accelerating pressure on Congress or the Supreme Court to clarify AI training copyright rules.
What to watch next
- Whether Ross Intelligence petitions for en banc rehearing or certiorari to the Supreme Court, which would be the next major escalation.
- How pending AI training copyright cases in other circuits (involving book publishers, news organizations, and image licensors) cite or distinguish this ruling.
- Whether major AI labs accelerate licensing deals or data-sourcing pivots in response, signaling that the industry reads this as a durable constraint rather than an outlier.
Originally published on Present of AI, a daily source-linked AI news timeline. Read the full timeline or browse the open dataset.