Sony Music Publishing and Warner Chappell Music initiated legal action against Anthropic on August 28, 2026, accusing the artificial intelligence developer of large-scale copyright infringement. The complaint, lodged in the US District Court for the Northern District of California, names Anthropic and its co-founders, Dario Amodei and Benjamin Mann, as defendants. The music publishers contend that Anthropic "illegally torrented, scraped, and downloaded copyrighted works on a massive scale" to develop its Claude series of AI models. They characterize this activity as "one of the largest and most blatant ongoing thefts of intellectual property in history."
The lawsuit alleges that Anthropic harvested "tens of thousands" of the publishers' musical compositions, including well-known songs such as "Ain't No Mountain High Enough," "All I Want for Christmas is You," and "Eye of the Tiger." The plaintiffs claim these works were systematically copied multiple times, both as inputs for training Anthropic's models and in the outputs generated by those models. The complaint also asserts that Anthropic removed copyright management information from these works.
Sony Music Publishing and Warner Chappell Music are seeking statutory damages of up to $150,000 for each willfully infringed work. Additionally, they are asking for up to $25,000 for each instance where copyright management information was allegedly removed or altered. Given the "tens of thousands" of compositions cited in the complaint, the potential damages could amount to several billion dollars if the court rules in favor of the music publishers and awards the maximum amounts. The publishers are also demanding a jury trial, the destruction of all infringing copies, and a full account of Claude's training data.
The complaint details specific allegations regarding the acquisition of training data. It claims that in June 2021, co-founder Benjamin Mann used BitTorrent to download at least five million pirated books from Library Genesis (LibGen). Subsequently, in July 2022, Anthropic employees allegedly torrented at least two million more books from Pirate Library Mirror. The publishers assert that these pirated hauls included hundreds of songbooks and sheet-music collections containing their copyrighted compositions. Furthermore, the lawsuit alleges that Anthropic scraped lyrics from licensed lyric websites, such as MusixMatch and LyricFind, in violation of their terms of service. The complaint also mentions a "destructive scanning" operation that purportedly digitized millions of second-hand physical books before destroying them, and the use of third-party datasets including Common Crawl, The Pile, and Books3.
Internal Anthropic documents, unsealed in a previous lawsuit, are cited in the current complaint. These documents reportedly include Mann's description of LibGen as "sketchy AF" and an Anthropic archive team's characterization of the site as a "blatant violation of copyright." A 2024 planning document about the scanning operation allegedly stated, "We don't want it to be known that we are working on this." The lawsuit specifically states that Dario Amodei and Benjamin Mann are personally liable for their roles in the alleged illegal torrenting of pirated copies.
This lawsuit follows a $1.5 billion settlement Anthropic reached in September 2025 with authors and publishers in the Bartz v. Anthropic class-action lawsuit. That settlement, approved by a federal judge in July 2026, compensated approximately 500,000 authors and publishers for the use of their pirated books in training Anthropic's AI models. The court in that case ruled that while training AI on lawfully acquired content could be considered fair use, the act of acquiring and storing pirated books to build a permanent library was a copyright violation. The Bartz settlement did not release Anthropic from suits involving the outputs from its large language models.
The current legal action by Sony Music Publishing and Warner Chappell Music is not the first against Anthropic by the music industry. Universal Music Publishing Group, Concord Music Group, and ABKCO filed a lawsuit in October 2023, which was later transferred to California. Those same publishers filed a second suit in January 2026, covering over 20,000 works and seeking more than $3 billion. BMG initiated a third case in March 2026, and Round Hill Music filed a fourth on August 17. Anthropic is reportedly seeking a valuation of about $2 trillion ahead of a potential public offering.