Anthropic at Risk: Pirated Books Lawsuit Could Cost Billions

The judge overseeing a copyright lawsuit filed against Anthropic by a group of authors has denied the company's request to stay the case. Anthropic sought to pause the proceedings while it appeals to a higher court. The company faces allegations of copyright infringement for downloading and storing more than 7 million "pirated" books. The judge argued that the appeals court would be better positioned to issue a ruling after the scheduled trial concludes in December. According to Anthropic's attorneys, the trial could expose the company to "potentially billions of dollars in liability." The plaintiffs, including authors Andrea Bartz, Charles Graeber, and Kirk Johnson, claim that Anthropic infringed copyrights by purchasing and downloading books, including their own, and using them to train its Claude models.

Fair Use Ruling: A Partial Victory for Anthropic

An earlier court ruling brought Anthropic partial success. Judge William Alsup, who is presiding over the case, ruled that using legally obtained books to train AI models falls under fair use, meaning that companies such as Anthropic do not have to pay licensing fees for such use. This ruling applies to situations in which the books were not obtained illegally. However, the court clearly distinguishes between legal and pirated sources. According to the court, the use of illegally obtained materials, such as books downloaded from piracy websites, is not protected by fair use. This ruling cleared the way for a separate trial concerning pirated copies and potential damages, scheduled for December 1, 2025.

Details of the Lawsuit

The lawsuit was filed last year by authors Andrea Bartz, Charles Graeber, and Kirk Johnson on behalf of a large number of authors. They claim that Anthropic committed "large-scale theft" of copyrighted works by downloading millions of books from piracy sites such as Library Genesis (LibGen) and Pirate Library Mirror (PiLiMi). These books were allegedly used to create a "central library" of digital works for training the Claude AI system, without any authorization from or compensation to copyright holders. The plaintiffs accuse the company of attempting to conceal the extent of the infringement. The plaintiff class includes all legal or beneficial owners of books with ISBNs or ASINs that Anthropic allegedly copied from these pirated sources. The court approved the case to proceed as a class action, expanding its impact to many other authors.

Billions at Stake and the Future of AI

If the court rules against Anthropic in December, damages could reach billions of dollars, potentially threatening the company's very existence. In his fair use ruling, Judge Alsup stated that training on legally obtained books does not harm the authors' market in a way that violates copyright law. However, the issue of pirated copies remains unresolved and could lead to significant financial penalties. This case is part of a broader wave of AI copyright lawsuits in which companies face allegations of using works to train models without authorization. For Anthropic, this means that despite its partial victory on fair use, the risk remains high—and the legal battle continues without delay.