Concord Music Group, Inc. v. Anthropic PBC
5:24-cv-03811
N.D. Cal.May 23, 2025Background
- Concord Music Group and co-plaintiffs ("Publishers") sued Anthropic PBC alleging copyright infringement relating to the use of their works in training AI models ("Claude").
- Three discovery disputes were presented regarding: (1) Anthropic's request for undisclosed prompts/outputs used by Publishers’ counsel; (2) sampling protocol for the production of Claude prompt-output data; and (3) confidentiality designations by Anthropic.
- Plaintiffs produced nearly 5,000 prompt-output pairs relied on in their pleadings but refused to produce additional, unused ones, claiming privilege.
- The court heard from expert witnesses, including a dispute over a declaration partially drafted/verified with AI, which impacted the credibility of that evidence.
- The court had previously ordered a statistically significant sample of Claude's outputs relating to song lyrics and reviewed arguments and statistical parameters for sampling.
- The parties also disputed the extent and appropriateness of confidentiality designations under the Protective Order for various classes of evidence.
Issues
| Issue | Plaintiff's Argument | Defendant's Argument | Held |
|---|---|---|---|
| Anthropic's request for all prompts/outputs & settings | Work product, privileged, already produced relied data | Privilege waived; need all prompts for context | Denied without prejudice; work product protection not broadly waived; request overbroad |
| Scope of sampling protocol for Claude prompt-output pairs | 5% margin of error for robust discovery | 25% margin sufficient; 5 million pairs too onerous | Margin of error set at ~11.3%; 5 million prompt-output pairs ordered under specified time ranges |
| Confidentiality designations on certain categories | "Highly Confidential – AEO" overused and unnecessary | Maintains high confidentiality is needed | Down-designation required for many; prompts/outputs to "Confidential"; some metrics/training data can remain AEO |
Key Cases Cited
- Fed. R. Civ. P. 26 (attorney work product doctrine governs discovery of materials prepared in anticipation of litigation)
- Republic of Ecuador v. Mackay, 742 F.3d 860 (9th Cir. 2014) (outlines protection for opinion attorney work product; "virtually undiscoverable")
- United States v. Sanmina Corp., 968 F.3d 1107 (9th Cir. 2020) (work product privilege can be waived by placing protected materials at issue; scope of waiver must be closely tailored)