On Friday, September 4, 2026, the Authors Guild and its co-plaintiffs (the class plaintiffs) filed a motion for summary judgment and supporting brief in their copyright litigation against OpenAI and Microsoft, in In re OpenAI, Inc., Copyright Infringement Litigation, MDL No. 25-md-3143, pending before Judge Sidney H. Stein in the Southern District of New York. The motion and brief ask the court to rule that defendants OpenAI and Microsoft infringed on the authors’ copyrights by pirating their works, copying them to train their AI, and trading the books between them as currency, and to reject the defendants’ fair use defense. The defendants also filed their own motions for summary judgement.

A summary judgment motion asks the court to rule as a matter of law, even when taking the facts as presented by the other side as valid. If the court determines that there are material disputed facts, then the case will proceed to trial.

The Guild and more than a dozen authors initially brought suit on September 19, 2023, and the case was consolidated with other pending class actions then centralized in a multi-district litigation along with The New York Times’ and other news companies’ suits on April 3, 2025. Along with the Authors Guild, the named plaintiffs in the consolidated class case are David Baldacci, Taylor Branch, Michael Connelly, Sylvia Day, Jonathan Franzen, Christopher Golden, Andrew Sean Greer, John Grisham, David Henry Hwang, George R.R. Martin, Jodi Picoult, Stacy Schiff, and James Shapiro. The class case and news cases have proceeded on the same schedule. Fact and expert discovery were completed this summer.

The plaintiffs’ brief argues that “OpenAI’s GPT models pose an existential threat to those who write and publish books.” The brief describes how, since the release of ChatGPT, “a torrent of AI-generated books of all types” has started flooding the market, threatening to “’substitute’ for the creations of authors.” Not only did OpenAI feed plaintiffs’ books to its models so that the models can regurgitate and create derivatives of the works with simple prompts by anyone in the world, but it also initially downloaded the books from pirate websites and quite literally “built the foundations of its business on mass piracy.”

Describing the actual and potential harm caused by defendants’ pirating and training as the “single most important element” in the fair use analysis, the brief lays out how unchecked and uncompensated use of copyrighted books by defendants will decimate the market for books and eviscerate the incentives to write new books afforded authors by the U.S. Constitution. As the brief states, “OpenAI’s models are capable of displacing human authors precisely because it exploited their works.”

This harm is here. The publicly-available evidence of market dilution shows a clear trend of “substitution” of human authored works. And public statements by OpenAI’s Head of Model Writing Quality Tarun Gogineni say it all: His “research mission” was to have GPT models write the “last two books of [plaintiff Martin’s] A Song of Ice and Fire” series.

Gogineni had described himself as having “an undue amount of power over the english language” and “recognized that the models’ writing capabilities depended entirely on their training data, stating that models’ abilities depended ‘the vast lineage of human mastery recorded in bytes, without which models could not do anything great.’” He knew authors were upset about having their works stolen and losing work due to AI, but stated that he was not “all that sympathetic,” viewing the displacement of writers as mere “acceptable economic disruption.”

Opposition briefs are due in early October with reply briefs due in early November.

You can read the plaintiffs’ brief here (PDF).