Sony Music Publishing and Warner Chappell sue Anthropic over alleged torrenting of lyrics and sheet music to train Claude

What happened

On 28 August 2026, Sony Music Publishing (US) LLC, Warner Chappell Music, Inc., and others filed a copyright infringement complaint against Anthropic PBC — and against CEO Dario Amodei and co-founder Benjamin Mann personally — in the U.S. District Court for the Northern District of California, San Jose Division (Case No. 5:26-cv-09217). The 48-page complaint (Document 1, read in full) calls the conduct "one of the largest and most blatant ongoing thefts of intellectual property in history" and alleges Anthropic "conducted a brazen campaign of illegally torrenting, scraping, and downloading copyrighted works on a massive scale" to train Claude.

The complaint alleges Mann used BitTorrent to torrent at least 5 million books from Library Genesis (June 2021) and at least 2 million more from Pirate Library Mirror (July 2022) at Amodei's direction, with both knowing the works were pirated; that Anthropic scraped lyrics and sheet music from licensed platforms Musixmatch and LyricFind as well as Common Crawl, The Pile, and Books3; and that Anthropic stripped copyright-management information. It further alleges Anthropic rewarded accurate reproduction of copyrighted lyrics during fine-tuning and that Claude reproduces lyrics verbatim when prompted. The publishers seek up to $150,000 per infringed work and up to $25,000 per instance of CMI removal, with total damages potentially reaching billions. These are allegations in a complaint; no ruling has issued on them. Anthropic has said it will defend itself robustly, citing the Bartz v. Anthropic fair-use ruling on training. A separate author/publisher suit against Anthropic (the "Shakespeare" matter) saw Anthropic file a statute-of-limitations motion to dismiss on 18 September 2026.

Why it may matter to you

This is the fifth music copyright suit against Anthropic and the first to name its CEO and co-founder personally. The alleged RLHF reward for verbatim lyric reproduction, if proven, would complicate the transformative-use defense. Universal Music Group's earlier lyrics suits against Anthropic remain ongoing.

What is not yet known

Whether discovery substantiates the torrenting and RLHF allegations; whether the personal liability claims against Amodei and Mann survive; how the September 2025 $1.5 billion Bartz settlement shapes settlement leverage here.