Sony and Warner sue Anthropic over "one of the largest and most blatant ongoing thefts of intellectual property in history"
Key Points
- Major music publishers including Sony Music and Warner Music have sued Anthropic and its executives personally.
- The AI company allegedly used tens of thousands of copyrighted compositions, mostly song lyrics, to train its Claude models without permission.
- The case centers on how Anthropic acquired the training data, not just how it used it.
Major music publishers accuse Anthropic of illegally downloading and using tens of thousands of copyrighted musical compositions to train Claude.
Sony Music, Warner Music, and other publishers have sued Anthropic in federal court in Northern California. According to the complaint, CEO Dario Amodei and co-founder Benjamin Mann are named as individual defendants for their alleged role in directing and overseeing the torrenting of copyrighted files.
"Dr. Amodei expressly directed, approved, controlled, and intentionally induced these infringements by Mr. Mann and other Anthropic employees," the 48-page complaint states. The plaintiffs call it "one of the largest and most blatant ongoing thefts of intellectual property in history."
The complaint focuses on musical compositions, mostly song lyrics, plus sheet music and derivative works. The plaintiffs are seeking up to $150,000 per infringed work and up to $25,000 per violation for unlawful removal of copyright management information, including copyright notices and other identifying information.
Anthropic has already lost this fight once
In September 2025, Anthropic agreed to the largest copyright settlement in U.S. history, paying $1.5 billion to authors and publishers for using pirated books during AI training. What sank Anthropic in that case wasn't using copyrighted data for training, but acquiring it through illegal torrent downloads.
The Sony-Warner lawsuit targets the same weak spot. Anthropic allegedly torrented at least seven million books from the pirate libraries LibGen and PiLiMi. The lawsuit treats that downloading as a standalone copyright infringement, regardless of whether the works ever made it into a commercial Claude model.
The company also allegedly scraped song lyrics from licensed platforms like MusixMatch and LyricFind without publisher consent, violating those platforms' terms of service. The complaint challenges Anthropic's use of datasets like Books3, The Pile, and Common Crawl, which allegedly contain unauthorized content. It also accuses the company of scanning and destroying used songbooks and sheet music collections.
Synthetic data as a copyright loophole
The plaintiffs also go after how Anthropic handled torrented content during training. Anthropic has publicly denied using LibGen and PiLiMi books directly to train commercial Claude models, but the complaint argues that denial depends on how Anthropic defines "training."
The plaintiffs allege Anthropic trained at least one commercial Claude model on synthetic data generated by a non-commercial model that had itself learned from LibGen and PiLiMi texts. They also claim Anthropic used such a model to provide reinforcement feedback to a commercial Claude model. The full scope of these claims will come out during discovery.
In a related case, the Munich Regional Court ruled in November 2025 that copyright-protected song lyrics count as reproductions even within a model's parameters and that chatbot output of those lyrics amounts to unlawful public disclosure. The court held model operators responsible for what their models produce, not the users who prompted the output, even when those prompts were specifically designed to generate copyrighted lyrics.
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