Microsoft sued by authors for allegedly using pirated books to train AI model

A group of prominent authors, including Pulitzer Prize winner Kai Bird and New Yorker writer Jia Tolentino, has filed a lawsuit against Microsoft , accusing the tech giant of illegally using pirated versions of their books to train its AI model known as “Megatron.” Filed in a New York federal court on June 25, the suit claims that Microsoft copied nearly 200,000 copyrighted works without permission to develop AI systems that mimic the authors’ unique writing styles, themes, and voices. This marks another major legal challenge in the growing debate over AI training and copyright law.

Authors accuse Microsoft of copyright infringement
The plaintiffs allege that Microsoft used a massive dataset of pirated digital books to train Megatron, a generative AI model designed to produce human-like text. According to the complaint, the AI’s ability to replicate the tone, syntax, and narrative patterns of copyrighted works demonstrates a clear violation of intellectual property rights. The authors argue that their creative output was exploited to build a product that competes with them in the marketplace, without their consent or compensation.

Lawsuit demands damages and a court injunction
The writers are seeking statutory damages of up to $150,000 per infringed work, along with a court order to block Microsoft from continuing its alleged unauthorised use of their materials. While the exact number of infringed titles remains unclear, the plaintiffs claim that thousands of authors’ works may have been used without licence or attribution. The case could set a precedent for how courts handle AI training involving copyrighted content.

Legal backdrop: A turning point in AI copyright battles
This lawsuit comes just one day after a California judge ruled that AI firm Anthropic may have made “fair use” of copyrighted material in training but could still be liable for using pirated versions of books. It was the first US decision to address the legality of using copyrighted texts in generative AI development. The Microsoft case adds further momentum to a wave of lawsuits from writers, artists, and media outlets challenging how their work is used by tech companies.

Microsoft yet to respond publicly
According to Reuters, Microsoft has not issued an official response to the allegations. A spokesperson for the company declined to comment when contacted by reporters. Meanwhile, legal observers say this case will be closely watched for its implications on the future of AI development and intellectual property rights.

A growing challenge for the AI industry
Tech firms including Meta, OpenAI, and Anthropic have all faced similar legal scrutiny in recent time. The central argument from the companies is that using public data for AI training qualifies as “fair use” under US copyright law. However, rights holders argue that this approach undermines creators' control and devalues their work. As AI models become increasingly sophisticated, courts should define clearer boundaries around what constitutes ethical and legal data usage.