The publishing arms of two of the three major music companies have joined the legal assault on Anthropic, alleging the AI lab's founders personally orchestrated the torrenting of millions of pirated books to train Claude.
The publishing arms of two of the three major music companies have joined the legal assault on Anthropic, alleging the AI lab's founders personally orchestrated the torrenting of millions of pirated books to train Claude.

Sony Music Publishing and Warner Chappell Music sued Anthropic and its co-founders Friday, seeking up to $150,000 per work for alleged copyright infringement tied to AI training data.
The publishers called the case "one of the largest and most blatant ongoing thefts of intellectual property in history," alleging a "brazen campaign of illegally torrenting, scraping, and downloading copyrighted works on a massive scale" to develop and operate the Claude series of AI models.
The suit, filed in the US District Court for the Northern District of California, alleges co-founder Benjamin Mann used BitTorrent in June 2021 to download at least five million pirated books from Library Genesis, with Anthropic employees torrenting at least two million more from Pirate Library Mirror in July 2022. The publishers identify "tens of thousands" of allegedly infringed compositions, placing Anthropic's theoretical statutory exposure in the multi-billion-dollar range. The complaint also alleges Anthropic scraped lyrics from licensed platforms including MusixMatch and LyricFind, and used Common Crawl, The Pile, and Books3 datasets.
The lawsuit marks the fifth major copyright action against Anthropic, following a $1.5 billion settlement with book authors in September 2025 and separate suits from UMG, Concord, ABKCO, BMG, and Round Hill Music. The complaint cites Anthropic's projected $2 trillion valuation from an August 2026 Forbes report on a planned October IPO, arguing the $1.5 billion settlement "is obviously not a large enough settlement to deter infringing conduct."
The complaint leans heavily on findings from Bartz v. Anthropic, the authors' case in which a judge in the same district described Anthropic's conduct as "straightforward piracy but at massive scale." Internal Anthropic material unsealed in that case shows Mann describing LibGen as "sketchy AF," while the company's own Archive Team called it a "blatant violation of copyright." A 2024 Anthropic planning document quoted in the filing reads: "We don't want it to be known that we are working on this."
Songs Named in the Complaint
The filing names beloved compositions including "Ain't No Mountain High Enough," "All I Want for Christmas is You," "Eye of the Tiger," "Livin' On a Prayer," "September," "Hallelujah," "Uptown Funk," and Taylor Swift's "Paper Rings." The publishers allege Claude reproduces their lyrics verbatim in outputs, and that guardrails added after earlier litigation from UMG, Concord, and ABKCO are "easily circumventable by simply 're-prompting'" the model.
Legal Exposure Mounts
The suit brings four counts: direct infringement by torrenting against all three defendants, contributory infringement by torrenting against Amodei and Mann, and direct infringement and removal of copyright management information against Anthropic alone. The publishers are represented by Oppenheim + Zebrak, LLP — lead counsel for the Concord/UMG case — and Pryor Cashman LLP. They are demanding a jury trial, destruction of all infringing copies, and an accounting of Claude's training data.
With the publishing arms of all three major music companies now litigating against Anthropic, cumulative statutory exposure across all pending cases could exceed $10 billion. The complaint argues that Anthropic's "ethical AI" branding is contradicted by its conduct: "Despite branding itself as the 'ethical AI company,' Anthropic has repeatedly acted in ways that belie that image, prioritizing competitive advantage over compliance with the law."
For investors tracking the AI sector, the case shows that training-data liability remains a structural risk for model developers. Anthropic's projected October IPO could face headwinds from unresolved litigation, and the precedent set here could affect how other AI companies — including Microsoft-backed OpenAI — source training data. Music Publishers said they "recognize the potential of ethical AI technology" and have entered licenses for authorized use, but insisted that "even the most revolutionary of technologies must develop within the bounds of the law."
This article is for informational purposes only and does not constitute investment advice.