Sony Music Publishing, Warner Chappell, and several other major music publishers have filed a lawsuit against Anthropic and its co-founders, alleging a “brazen campaign” of intellectual property theft. The complaint, lodged in the U.S. District Court for the Northern District of California on August 28, 2026, accuses Anthropic of illegally torrenting, scraping, and downloading millions of copyrighted works to train its AI model Claude. This includes music-related content such as lyrics and sheet music, intensifying prior legal disputes around unauthorized use of protected materials.

The lawsuit marks a significant escalation in ongoing conflicts between Anthropic, an AI research lab, and the music publishing industry. The plaintiffs describe Anthropic’s behavior as “blatant theft” and “flagrant piracy,” highlighting the scale and scope of the alleged copyright violations. Anthropic has responded by rejecting the claims and expressing its intention to defend itself firmly in court. This case draws attention to the controversial practices involved in sourcing training data for AI systems and the legal ramifications facing AI developers.

This is not Anthropic’s first lawsuit involving intellectual property infringement. The same legal teams behind this case also represent Concord Music Group and Universal Music Group in an earlier suit filed in January 2026. Furthermore, Anthropic recently settled a separate landmark case, Bartz v. Anthropic, where it was ordered to pay $1.5 billion after a court determined that while using copyrighted works for AI training could be lawful if obtained legally, Anthropic had acquired many of the materials through piracy.

The latest lawsuit builds on these earlier proceedings but widens its focus by emphasizing claims of illegal torrenting as a method Anthropic allegedly used to amass copyrighted content. This legal development underscores the growing tension between content owners and AI companies over responsible data sourcing. As the battle continues, the outcome may have far-reaching implications for the music industry’s role in AI development and the boundaries of lawful training data use.