A Delaware district court granted partial summary judgment to Thomson Reuters in February 2025, finding that Ross Intelligence's use of Westlaw's copyrighted headnotes and Key Number system to train a competing legal research AI was neither transformative nor shielded by fair use, because the product directly substituted for the plaintiff's market. The ruling established that a potential licensing market for AI training data can satisfy the fourth fair use factor, meaningfully narrowing the fair use defense for AI developers whose products compete with source material. The case is stayed pending Third Circuit interlocutory appeal, but it has already been cited in subsequent AI copyright cases, including Bartz v. Anthropic, raising the quantifiable legal exposure for AI vendors whose training pipelines relied on commercially curated content without licensing agreements.
185 other tracked developments touching the same claims.