Sony and Warner Music sue Anthropic over AI training on 20,000 copyrighted songs

Allegations of song piracy

Sony Music Publishing and Warner Chappell Music filed a 48-page copyright infringement lawsuit against artificial intelligence company Anthropic in the U.S. District Court for the Northern District of California. The complaint also names Anthropic chief executive Dario Amodei and co-founder Benjamin Mann as individual defendants. The music publishers allege that Anthropic pirated sheet music and lyrics from more than 20,000 copyrighted songs to train its Claude family of AI models. Works cited in the filing include compositions by The Beatles, Michael Jackson, Taylor Swift's "Paper Rings", Mariah Carey's "All I Want for Christmas Is You", and Marvin Gaye and Tammi Terrell's "Ain't No Mountain High Enough". According to the complaint, Claude reproduces protected lyrics verbatim upon user prompt and generates derivative lyrics that compete directly with original song catalogs.

Torrenting operations and internal records

The lawsuit traces Anthropic's data acquisition practices back to July 2021, asserting that Mann used BitTorrent networks to download millions of pirated files from the illicit repository Library Genesis. After federal law enforcement disrupted Library Genesis late in 2021, the company allegedly continued obtaining scraped texts from mirror repositories such as Z-Library with executive approval from Amodei. Publishers argue that these materials included thousands of songbooks, sheet music anthologies, and compilations like "VH1's 100 Greatest Songs of Rock & Roll". The complaint contends that Anthropic retained these files permanently to build models capable of mimicking distinctive songwriting styles, such as restructuring rap verses into pop arrangements.

The publishers described the model's reliance on unauthorized material in their California court filing.

Anthropic clearly considers that to be just the cost of doing business given that its entire business model continues to be built on copyright theft.

Fair use defense and author precedents

Anthropic responded by asserting that training generative artificial intelligence models constitutes fair use under United States copyright law. A company representative stated that the new lawsuit reuses legal arguments from earlier court actions.

Training generative AI models is a transformative fair use -- as the court held in Bartz -- and we will defend ourselves robustly.

The statement referenced the class action Bartz v. Anthropic, which the startup settled for $1.5 billion after authors accused the company of ingesting over 7 million pirated books. In that case, the presiding judge determined that while training on copyrighted content can qualify as fair use, acquiring training data through illicit piracy remains unlawful. The lawyers representing Sony and Warner previously represented the plaintiff class of authors in the Bartz litigation.

Expanding legal exposure across the music sector

The publishers are asking the court for an injunction prohibiting Anthropic from using their musical catalogs, alongside statutory damages reaching up to $150,000 for each infringed work. The lawsuit follows several earlier copyright actions against Anthropic from the recording industry. Universal Music Group, Concord Music Group, and Abkco filed suit in 2023 seeking $3 billion in damages for unauthorized use of compositions by artists such as Beyoncé and The Rolling Stones. German publisher BMG filed an action in March 2026 covering 493 songs, followed by another complaint from Round Hill Music in August 2026.