Third Circuit Affirms Thomson Reuters Win Over ROSS on Westlaw Headnotes and Fair Use

# What happened The Third U.S. Circuit Court of Appeals has ruled for Thomson Reuters in its long-running copyright dispute with ROSS Intelligence. The court affirmed a February 2025 summary judgment by Judge Stephanos Bibas that was previously entered in favor of Thomson Reuters.

# What the court decided The panel resolved the two main legal questions that were before it:

• Whether Westlaw headnotes are protected by copyright. The court affirmed that the headnotes are sufficiently original to qualify for copyright protection.
• Whether ROSS's internal use of those headnotes to train its legal-research system was fair use. The court concluded it was not fair use.

The appellate judgment keeps those lower-court rulings in place.

# Procedural posture and public access The opinion was issued under seal while the court allows the parties to propose redactions. Because the published opinion is not yet public, the Third Circuit entered judgment without releasing the full written opinion for immediate public review. This was an interlocutory appeal of a summary-judgment order rather than a final-judgment appeal.

# Why the ruling matters to the parties For Thomson Reuters, the ruling preserves the company's copyright protections for its editorial content and affirms the lower court's finding that ROSS's use of that content did not qualify as fair use. Thomson Reuters told Reuters it was pleased with the outcome.

ROSS has said it will seek review in the U.S. Supreme Court. That procedural step follows the appellate loss and indicates the dispute may continue beyond the Third Circuit.

The factual record the lower court relied on included two distinctive points:

• ROSS's copying happened before the widespread popularity of generative models and before current mainstream practices for model training.
• ROSS used the headnotes to build a direct competitor to Thomson Reuters' product.

Those facts shaped the summary-judgment rulings and may limit how broadly the appellate opinion will be read once released. If the appellate opinion closely tracks the lower-court findings tied to these facts, its practical reach could be confined to similar scenarios. If the opinion states broader legal principles, it could affect other lawsuits about the use of publishers' materials to develop competing services.

# What to watch next

• Whether the Third Circuit releases a redacted opinion and the specific legal reasoning it adopts.
• Whether ROSS files a petition for certiorari with the Supreme Court and, if so, how the Court responds.
• How other litigants and courts treat this judgment in cases that involve training of automated research or model systems using copyrighted source material.

# Bottom line Westlaw headnotes are copyrightable and that ROSS's internal use of those headnotes to train its product was not protected by fair use. The full written opinion remains under seal pending redaction requests, and ROSS plans to pursue further review.