IP Law Daily, COPYRIGHT—N.D. Cal: Court refuses to halt proceedings in copyright class action against Anthropic, (Aug 12, 2025)

By George Basharis, J.D.

Judge finds trial should proceed despite pending appellate review of class certification and fair use rulings.

A federal judge in San Francisco has denied Anthropic PBC’s request to pause proceedings in a copyright class action over the artificial intelligence company’s alleged downloading of millions of pirated books. The ruling leaves intact a December 1, 2025, trial date while the Ninth Circuit considers whether to grant interlocutory review of the court’s class certification decision and partial summary judgment order, which upheld fair use for certain lawfully obtained books but left infringement claims over millions of alleged pirate library copies for trial (Bartz v. Anthropic PBC, No. 3:24-cv-05417-WHA (N.D. Cal. Aug. 11, 2025)).

The lawsuit, filed in August 2024 by several authors on behalf of a proposed class, challenges Anthropic’s acquisition of books from multiple sources to train its Claude large language model. The court previously found that Anthropic’s use of lawfully purchased and scanned print books for training was transformative and qualified as fair use under the Copyright Act. However, it denied summary judgment as to millions of works obtained from “pirate libraries,” concluding a trial was necessary to determine whether that copying was lawful.

On July 17, 2025, the court certified a narrowed “LibGen & PiLiMi Pirated Books Class” covering owners of timely registered copyrights in books identifiable by ISBN or ASIN numbers that Anthropic allegedly downloaded from the LibGen and PiLiMi repositories. The court excluded works from the “Books3” dataset, a large collection of digital books obtained from an online repository used in some AI training, citing incomplete metadata. The court also excluded lawfully purchased and scanned works. In certifying the class, the court concluded that common questions predominated and that individual actions were not a realistic alternative, given the scale of alleged copying and the resources required to litigate.

Anthropic’s bid for a stay. Anthropic moved on July 24, 2025, to stay all proceedings while it sought Ninth Circuit review of the class certification order under Rule 23(f) and potential interlocutory review of the partial summary judgment order. In that earlier ruling, the court found Anthropic’s use of lawfully purchased and scanned books to be fair use but left for trial the question of whether its downloading of millions of works from pirate libraries was lawful. The company argued that the certified class could encompass millions of works and create potential statutory damages exposure in the billions, exerting extreme settlement pressure regardless of the merits. Anthropic contended that the certification ruling presented an unsettled and fundamental question of class action law, namely whether such a large and diverse copyright class could satisfy Rule 23’s requirements, and that the court's rulings on fair use conflicted with other recent decisions.

Anthropic warned that absent a stay, the parties would be forced to complete discovery, pretrial preparation, and class notice while appellate proceedings were pending, potentially wasting resources if the Ninth Circuit reversed or narrowed the class.

Plaintiffs push forward as amici back review. Plaintiffs opposed the stay, maintaining that the case should proceed to trial on schedule. An amicus brief filed in the Ninth Circuit by the Authors Alliance, the Electronic Frontier Foundation, and others supported Anthropic’s petition for review. While not taking a position on liability, the amici argued that the district court’s certification decision failed to rigorously assess whether the proposed class satisfied Rule 23’s adequacy and commonality requirements. They cautioned that without prompt appellate review, fundamental questions about the viability of large, heterogeneous copyright classes might evade review entirely, as the magnitude of potential damages could compel settlement.

Court’s denial of the stay. In a detailed order, the court rejected Anthropic’s request. On the fair use issues, the court acknowledged their importance but found they should be adjudicated at trial on a full evidentiary record. The court noted unresolved factual questions about Anthropic’s downloading of entire pirate library collections, its use of BitTorrent to acquire them, and the extent to which those works were actually used in training Claude. The court emphasized that Anthropic retained all the downloaded works, even when only subsets were used for training, and had not fully disclosed which works fell into each category.

The court criticized Anthropic’s request for a broad legal ruling that it could lawfully copy and retain all pirated works so long as any portion was later used in training, finding such a rule inconsistent with the statutory fair use factors, particularly the “amount and substantiality” factor. The order stressed that it was Anthropic’s burden to prove how much was copied for a qualifying purpose and that a trial would better illuminate those facts.

On the stay factors, the court found that Anthropic had not shown a likelihood of success on the merits sufficient to justify halting proceedings. The court also determined that Anthropic had not established irreparable harm beyond the ordinary burdens of litigation and rejected the argument that the possibility of large damages warranted a stay. The public interest and judicial efficiency favored moving forward, the court concluded, noting that appellate review would be more meaningful after a complete trial record was developed.

The Case is No. 3:24-cv-05417-WHA.

Judge: Alsup, W.

Attorneys: Justin A. Nelson (Susman Godfrey L.L.P.) for Andrea Bartz. Douglas Andrew Winthrop (Arnold & Porter Kaye Scholer LLP) for Anthropic PBC.

Companies: Anthropic PBC

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