Anthropic becomes the latest AI company to be sued over how it trained its AI models. Sony Music Publishing and Warner Chappell Music took Anthropic and its co-founders to a federal court in Northern California. The suit was filed late on Friday, August 28, and it accuses the AI firm of pirating over 20,000 songs to train its Claude chatbot. The lawsuit comes amid growing copyright suits against AI companies. Just last year, Anthropic was ordered to pay $1.5 billion by the courts after it was sued by authors in another piracy case. The plaintiffs in this case argue Anthropic has not changed its pattern of pirating copyrighted content.Why are publishers suing Anthropic? The 48-page filing tells of Anthropic’s antics, calling it “one of the largest and most blatant ongoing thefts of intellectual property in history,” naming CEO Dario Amodei and co-founder Benjamin Mann as individual defendants as well as the company. The plaintiffs accuse the Amodei-led firm of running “a brazen campaign of illegally torrenting, scraping, and downloading copyrighted works” just to train Claude.The suit gets more detailed as it describes how the copyrighted materials were allegedly obtained. Co-founder Benjamin Mann is accused of obtaining over five million pirated books using BitTorrent while his employees pulled down 2 million more from Pirate Library Mirror. Those books contained lyrics and sheet music. Anthropic also obtained lyrics from MusixMatch and LyricFind; both services pay the labels for the license to their content.The catalog Anthropic allegedly pirated The publishers allege the piracy of popular songs like Mariah Carey’s “All I Want for Christmas is You,” Taylor Swift’s “Paper Rings,” Marvin Gaye and Tammi Terrell’s “Ain’t No Mountain High Enough,” Bon Jovi’s “Livin’ on a Prayer,” Earth, Wind & Fire’s “September,” and Leonard Cohen’s “Hallelujah.”Sony and Warner seek a jury trial and statutory damages to the tune of $150,000 per pirated copy, as well as $25,000 for each time copyright information was copied from a work. That amounts to billions of dollars for over 20,000 songs. In matters pertaining to individually copyrighted commercial recordings, plaintiffs need not prove they lost money before seeking statutory damages.Why the piracy claim is a big dealThe manner of acquiring the music catalog is what makes this a big deal for Anthropic. This all leads back to the author’s case from 2025. The judge ruled that using copyrighted work to train AI can pass as fair use, but downloading such works from pirated sources is against the law. That led to the $1.5 billion settlement, and Sony and Warner have made reference to the judge’s ruling in that case, claiming Anthropic’s business model is “built on copyright theft.”The irony is not lost on anyone who has been paying close attention to the AI industry. AI labs jealously guard their systems against distillation, the practice of training a rival model on another model’s outputs, calling it the pilfering of proprietary work. The same firm(s) protecting their intellectual property are now accused of stealing the proprietary work of others. Anthropic’s responseAnthropic is not going down without a fight, saying, “We disagree with the publishers’ claims, and we intend to defend ourselves robustly in court.” The company continued its response by calling this “the third lawsuit from the same lawyers, recycling allegations from cases already before the courts,” and reiterating that model training is “a transformative fair use.”The suit comes in the wake of other lawsuits against Anthropic from Universal Music Group, Concord, BMG, and Round Hill Music. It remains to be seen whether or not US courts will label AI training on copyrighted material as fair use. If you're reading this, you’re already ahead. Stay there with our newsletter.