District Court Finds That Using Copyrighted Works To Train Large Language Models Is Fair Use

In a significant ruling issued on June 23, 2025, the U.S. District Court for the Northern District of California held that using copyrighted works to train large language models (LLMs) is fair use under U.S. copyright law. The court found such use is "exceedingly transformative" and does not displace demand for or harm the market for the original works.

The court granted summary judgment for defendant Anthropic PBC, finding both that using copyrighted works for training LLMs was a fair use, and that Anthropic's creation of a digital library by purchasing and digitizing millions of print books was a fair use. The court, however, found the use of downloaded pirated copies to build Anthropic's central library was not justified by fair use, and thus denied summary judgment for Anthropic that the pirated library copies must be treated as training copies.