Anthropic's copyright battle just escalated. On August 29, Sony Music Publishing and Warner Chappell filed suit against Anthropic in the U.S. District Court for the Northern District of California, this time over how Claude was trained. The 48-page complaint targets Anthropic's acquisition methods rather than the question of training itself as fair use — and it's notably broader than previous actions: while BMG's earlier suit covered 493 compositions, Sony/Warner cite "tens of thousands."
The complaint names co-founders Dario Amodei and Benjamin Mann as individual defendants and groups the alleged conduct into three buckets: more than five million pirated books downloaded via BitTorrent, at least two million more from Pirate Library Mirror, and lyrics scraped from licensed sites such as MusixMatch and LyricFind. The plaintiffs argue the activity funded Claude and "enormous profits" for Anthropic.
The damage math is what changes the stakes
The plaintiffs are asking for up to $150,000 per infringed work plus up to $25,000 for each instance of stripped copyright metadata — at the upper end, several billion dollars. That tracks a pattern: book publishers extracted roughly $1.5 billion in a prior Anthropic settlement, and Universal, Concord, ABKCO, BMG, and Round Hill Music had each filed separately. What changes here is that Sony and Warner are aiming directly at the BitTorrent and Pirate Library Mirror channels — activities that Bartz v Anthropic already established as copyright infringement, distinct from the still-open question of whether training itself is fair use. Songs specifically named in Anthropic's training data include "Ain't No Mountain High Enough," "Livin' On a Prayer," "September," "Hallelujah," and Taylor Swift's "Paper Rings."
Why this is a leading indicator, not just one more lawsuit
OpenAI spent the past two years signing licensing agreements — News Corp, Axel Springer, and others — precisely to avoid this kind of fight. Sony and Warner chose instead to sue for statutory-max damages and put founders personally in the defendants' chair. For Claude, that means the cost of getting training data provenance right is going up, not down. The legal precedent set by this case will shape every future AI-training fight that touches the music catalog — and possibly the publishing catalog too, given that the conduct alleged is identical to what already cost Anthropic a nine-figure settlement on the book side.