Sony Music Publishing and Warner Chappell Music have joined forces to sue Anthropic, home of Claude, over what the publishers call “one of the largest and most blatant ongoing thefts of intellectual property in history.”

The complaint – obtained by MBW, and which you can read in full here – also names Anthropic Co-Founder and Chief Executive Officer Dario Amodei and Co-Founder Benjamin Mann as individual defendants.

It was filed on Friday (August 28) in the US District Court for the Northern District of California.

With Sony Music Publishing and Warner Chappell Music launching their own suit as plaintiffs, the publishing arms of all three major music companies are now litigating against the Claude maker.

Universal Music Publishing Group, Concord Music Group, and ABKCO sued in Nashville in October 2023 over roughly 500 songs, in a case later transferred to California.

The same publishers filed a second suit in January 2026 covering more than 20,000 works and seeking over USD $3 billion.

BMG brought a third case in March 2026 over 493 compositions, and Round Hill Music filed a fourth on August 17.

Sony and Warner are seeking statutory damages of up to $150,000 per work willfully infringed, plus up to $25,000 for each alleged removal of copyright management information.

Among the innumerable copyrighted works Defendants illegally harvested to fuel Claude are thousands upon thousands of Music Publishers’ copyrighted musical compositions, including such beloved songs as “Ain’t No Mountain High Enough,” “All I Want for Christmas is You,” “Eye of the Tiger,” “Here Comes Santa Claus,” and “Paper Rings.” In blatant violation of copyright law, Defendants have unlawfully acquired troves of Music Publishers’ musical compositions, and then systematically copied those works multiple times, including as the inputs to train Anthropic’s Claude AI models and in the outputs those models generate.”

Sony Music Publishing/Warner Chappell Music complaint

The complaint identifies “tens of thousands” of the publishers’ allegedly infringed compositions – a characterization that would place Anthropic‘s theoretical statutory exposure in the multi-billion-dollar range.

Sony Music Publishing (SMP) and Warner Chappell Music (WCM) are demanding a jury trial, and are being represented in the suit by Oppenheim + Zebrak, LLP – the lead counsel for the Concord/UMG vs Anthropic case – and by Pryor Cashman LLP.

SMP and WCM are also demanding that all infringing copies of the works are destroyed, and that Anthropic supplies an account of Claude‘s training data.

The suit brings four counts: (i) direct infringement by torrenting, against all three defendants; (ii) contributory infringement by torrenting, against Amodei and Mann; and, against Anthropic alone, (iii) direct infringement and (iv) removal or alteration of copyright management information.

SMP and WCM’s complaint alleges that in June 2021, Mann used BitTorrent to download at least five million pirated books from Library Genesis, and that Anthropic employees torrented at least two million more from Pirate Library Mirror in July 2022.

Both figures are drawn from findings in Bartz v. Anthropic, the authors’ case in which another judge in the same district described Anthropic‘s conduct as “straightforward piracy but at massive scale.”

“Dr. Amodei and Mr. Mann are personally liable for their respective roles in this illegal torrenting of pirated copies of Music Publishers‘ works from LibGen and PiLiMi,” the complaint states.

The filing cites internal Anthropic material unsealed in Bartz, including Mann‘s description of LibGen as “sketchy AF.”

It also states that Anthropic’s own Archive Team had described LibGen as a “blatant violation of copyright.”

“[we] bring this action to hold accountable the culprits behind one of the largest and most blatant ongoing thefts of intellectual property in history. Defendants Anthropic and its founders Dario Amodei and Benjamin Mann have conducted a brazen campaign of illegally torrenting, scraping, and downloading copyrighted works on a massive scale in order to develop, operate, and reap enormous profits from Anthropic’s “Claude” series of artificial intelligence (“AI”) models.”

Sony Music Publishing/Warner Chappell Music complaint

The publishers further allege that Anthropic scraped lyrics from licensed sites including MusixMatch and LyricFind, ran a “destructive scanning” operation on second-hand books, and used Common Crawl, The Pile, and Books3.

On the last of these, the complaint says Mann downloaded pirated books “to avoid the trouble of paying for them, hoping they might prove useful for training large language models (LLMs) or something else” – quoting Bartz.

On the scanning, it quotes a 2024 Anthropic planning document unsealed in Bartz: “We don’t want it to be known that we are working on this.”

The publishers further allege that Claude reproduces their lyrics verbatim in outputs, and that guardrails added after earlier litigation (from UMG/Concord/ABKCO) are “easily circumventable by simply ‘re-prompting’” the model.

Song titles named in the body of the filing as being allegedly infringed include 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 complaint leans heavily on Anthropic‘s $1.5 billion settlement with book authors, agreed in September 2025 over the same torrenting conduct.

“But 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,” it states. “And $1.5 billion is obviously not a large enough settlement to deter infringing conduct by a company that has parlayed such mass infringement into a staggering $2-trillion-dollar valuation.”

That valuation figure is attributed in the filing to an August 2026 Forbes report on a projected October IPO.

The publishers also take aim at Anthropic‘s positioning: “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.”

The Sony and Warner Chappell complaint adds: “Music Publishers recognize the potential of ethical AI technology, and they have entered licenses permitting the authorized use of their musical compositions in connection with AI.

“It remains crucial, however, that AI development occurs responsibly and on terms that are agreeable to rightsholders and in a manner that protects their rights, livelihoods, and the creative industries as a whole.

“Even the most revolutionary of technologies must develop within the bounds of the law, and Anthropic‘s Claude models are no different.”Music Business Worldwide