On May 19, 2025, Wilson Sonsini secured summary judgment for OpenAI in the first-ever case charging a generative AI company with defamation based on an AI output. The plaintiff, Mark Walters, is a nationally prominent gun rights advocate and radio show host. His defamation claim arose from a journalist's use of ChatGPT in May 2023, where the journalist asked ChatGPT to read and summarize a legal complaint hosted on the web. ChatGPT incorrectly summarized the lawsuit as involving allegations of embezzlement against Walters. 

Wilson Sonsini took over the case after the court had previously denied a motion to dismiss Walters’ claims. In a precedent-setting ruling, Judge Cason of the Superior Court of Gwinnett County, Georgia, granted summary judgment to OpenAI on multiple independent grounds. Based on the factual record developed by our team, Judge Cason held, among other things, that ChatGPT’s output could not reasonably be understood as defamatory and that Walters had failed to prove that OpenAI acted with fault. 

This decision sets important precedent in this fast-evolving area of law. 

The Wilson Sonsini team that represented OpenAI in this matter included attorneys Matthew Macdonald, Stephanie Jensen, Catherine Hartman, Benjamin Margo, Ara Astourian, and Madelyn Chen. In addition, Naomi Pierce, Michael Lamb, and Mary Pantoja provided invaluable support.