Lawsuit tracker
Music Publishers v. Anthropic
Concord Music Group, Inc. et al. v. Anthropic PBC, No. 5:24-cv-03811 (N.D. Cal.), with follow-on No. 5:26-cv-00880 (N.D. Cal.)
| Plaintiffs | Music publishers including Universal Music Publishing Group entities, Concord Music Group and ABKCO |
|---|---|
| Defendants | Anthropic PBC |
| Court | U.S. District Court for the Northern District of California (filed in the Middle District of Tennessee, transferred 2024) |
| Filed | 2023-10-18 |
| Status | Active |
| Content type | song lyrics |
| Last updated | 2026-07-21 |
The claims
Copyright infringement of lyrics used in training and reproduced in Claude outputs; the 2026 follow-on complaint adds claims over more than 20,000 musical works allegedly sourced from pirate libraries and seeks roughly $3 billion.
What has happened
The publishers sued in October 2023, alleging Claude was trained on lyrics to roughly 500 works and would reproduce them, or close paraphrases, on request. The case moved from Nashville to the Northern District of California in 2024. In January 2025 Anthropic stipulated to maintaining output guardrails against reproducing the publishers’ lyrics. In March 2025 the court denied a preliminary injunction against training use, finding the publishers had not shown irreparable harm, while allowing further evidence-gathering. Fact and expert discovery closed in the original case, and on March 23, 2026 the publishers moved for partial summary judgment, arguing the infringement evidence is overwhelming and fair use does not excuse it. In January 2026 the same publishers filed a second suit, reported at roughly $3 billion over more than 20,000 works, built in part on evidence from the separate Bartz v. Anthropic record about pirated source libraries. Anthropic moved to stay the second case pending the first; the court refused on April 24, 2026, with Anthropic’s response due August 3, 2026. Industry groups including the RIAA and NMPA have filed amicus support for the publishers.
Key developments
- 2023-10-18 — Publishers sue in the Middle District of Tennessee over roughly 500 works, the first major music-industry case against an LLM developer.
- 2024-06 — Case transferred to the Northern District of California.
- 2025-01 — Anthropic and the publishers stipulate that Claude will maintain output guardrails against reproducing the publishers’ lyrics.
- 2025-03 — Court denies the publishers’ preliminary injunction against use of lyrics in training, citing lack of shown irreparable harm.
- 2026-01 — Publishers file a follow-on suit reported at roughly $3 billion covering more than 20,000 works, alleging sourcing from pirate shadow libraries.
- 2026-03-23 — Publishers move for partial summary judgment in the original case, asking the court to reject Anthropic’s fair-use defense.
- 2026-04-24 — Court denies Anthropic’s motion to stay the follow-on case; Anthropic’s response due August 3, 2026.
Why it matters for training data
Lyrics are licensed text with an existing market, which makes this a cleaner damages story than most scraping cases: the publishers can point to what licensed use already costs. The case also shows escalation mechanics. A contained 500-work dispute became a reported $3 billion claim once discovery in an unrelated case surfaced how source datasets were assembled — evidence found in one lawsuit fed another. For data buyers, vendor diligence now includes the discovery exhaust of other dockets. The pending fair-use ruling on lyrics-in-training will read across to any text corpus containing licensed lyrical content.
Sources
- Music Business Worldwide on the $3bn follow-on suit
- Music Business Worldwide on the partial summary-judgment motion
- Music Business Worldwide on the injunction denial
- Musically on the March 2026 summary-judgment filing
- Anthropic motion to stay Concord II (filing PDF)
Deeper analysis
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