Ann Altman, the younger sister of OpenAI’s CEO and co-founder, Sam Altman, has filed a lawsuit accusing him of sexually abusing her when she was a minor.

The suit, filed in US District Court for the Eastern District of Missouri on Monday (Tuesday NZT), said that the abuse occurred in
the Altmans’ family home outside St Louis from 1997 to 2006 and started when Ann Altman was 3 years old.

The lawsuit said Altman had sustained bodily injury and had “experienced PTSD, severe emotional distress, mental anguish and depression, which is expected to continue into the future”, as a result of the abuse.

Altman has long made similar sexual assault claims against her brother on social media platforms like X. She is represented by an Illinois-based law firm that specialises in sexual assault and harassment cases.

In a statement posted to X on Tuesday, Sam Altman, along with his mother and two younger brothers, denied the claims. “Annie has made deeply hurtful and entirely untrue claims about our family, and especially Sam,” the statement said. “This situation causes immense pain to our entire family.”