Sony Music Publishing and Warner Chappell Sue Anthropic for Alleged Copyright Infringement

On August 28, 2026, Sony Music Publishing and Warner Chappell Music filed a lawsuit against Anthropic and its co-founders, claiming the company used tens of thousands of copyrighted musical works to train its Claude AI models. The complaint, lodged in the U.S. District Court for the Northern District of California, identifies CEO Dario Amodei and co-founder Benjamin Mann as individual defendants alongside Anthropic.

Allegations of Massive Intellectual Property Theft

The plaintiffs, a collection of publishing entities known as the Music Publishers, describe Anthropic’s conduct as “one of the largest and most blatant ongoing thefts of intellectual property in history.” Notable songs cited in the lawsuit include classics like “Ain’t No Mountain High Enough,” “All I Want for Christmas is You,” and Taylor Swift’s “Paper Rings.” The publishers are advocating for a jury trial to seek justice.

The Four Key Legal Claims

The lawsuit comprises four primary claims. The first alleges direct copyright infringement via torrenting against all three defendants. The second accuses Amodei and Mann of personally contributing to this infringement. The third and fourth claims target Anthropic alone, alleging direct violation through scraping, downloading, model training, and AI outputs, plus tampering with copyright management information.

Details of the Allegations

The complaint outlines that Mann allegedly utilized the BitTorrent protocol in June 2021 to download over five million pirated books from Library Genesis (LibGen). Further, Anthropic employees reportedly downloaded an additional two million works from a site called Pirate Library Mirror in July 2022. These downloads allegedly included hundreds of songbooks and sheet music containing the publishers’ works, with claims that Amodei authorized these actions. Since BitTorrent users share files as they download, the complaint argues this activity violates the publishers’ distribution rights.

Unauthorized Data Scraping and Operative Procedures

Additionally, the publishers contend that Anthropic illegally scraped lyrics from licensed websites such as MusixMatch and LyricFind, violating these sites’ terms. They also claim the company engaged in “destructive scanning” of second-hand physical books and relied on various third-party datasets. The publishers emphasize that they have never granted Anthropic permission to utilize their works in any of these manners.

AI Model Development and Copyright Issues

The filing details how unlicensed lyrics are integrated into Anthropic’s AI development process. It is alleged that engineers “clean” the text of copyright notices and ownership details, a process described by the publishers as intentional concealment. The lawsuit contends that Claude models can memorize and reproduce lyrics verbatim or even create derivative works mimicking the style of well-known songwriters.

Concerns Over AI’s Market Impact

The publishers acknowledge that while Anthropic implemented guardrails to prevent copyright infringement following previous litigation, these measures can be easily bypassed through re-prompting. They argue that Claude’s capability to generate new lyrics competes directly with the publishers’ catalog, significantly impacting their streaming royalties.

Reference to Bartz Findings

A substantial portion of the complaint is based on findings from Bartz v. Anthropic, where the court concluded that Anthropic had engaged in large-scale torrenting of pirated books. Anthropic settled that case for $1.5 billion in September 2025. The new complaint cites internal documents revealing Mann’s negative characterization of LibGen and acknowledges past copyright violations.

Damages Sought and Future Implications

The publishers are pursuing statutory damages of up to $150,000 for each willful infringement and up to $25,000 for each violation related to the alteration of copyright management details. They also request the court to mandate Anthropic to destroy all infringing copies and provide transparency regarding its training data and methods.

In closing, the publishers express a recognition of the potential for ethical AI and have entered into agreements with other AI companies for authorized use of their songs. “Even groundbreaking technologies must operate within legal frameworks, and Anthropic’s Claude models are no exception,” the complaint asserts. As of the filing date, Anthropic had not yet publicly responded to the lawsuit.