OpenAI chief executive Sam Altman accused of sexual abuse by sister in lawsuit | Sam Altman

The sister of the OpenAI chief executive, Sam Altman, has filed a lawsuit alleging that he regularly sexually abused her for several years, starting when they were children.

The lawsuit filed on 6 January in a US district court in the Eastern District of Missouri alleges that the abuse began when Ann Altman was three and Sam Altman was 12. The filing alleges that the last instance of abuse took place when he was an adult but his sister, known as Annie, was still a child.

The chief executive of the ChatGPT developer posted a joint statement on X, which he had signed along with his mother, Connie, and his younger brothers, Max and Jack, denying the allegations and calling them “utterly untrue”.

“Our family loves Annie and is very concerned about her wellbeing,” the statement said. “Caring for a family member who faces mental health challenges is incredibly difficult.”

It added: “Annie has made deeply hurtful and entirely untrue claims about our family, and especially Sam. This situation causes immense pain to our entire family.”

Ann Altman has previously made similar allegations against her brother on social media platforms.

In the court filing, her lawyers said she had experienced mental health issues as a result of the alleged abuse. The lawsuit is requesting a jury trial and damages in excess of $75,000 (£60,000) as well as legal fees.

The family statement said Ann Altman had made “deeply hurtful and entirely untrue claims” about the family and accused her of demanding more money.

They added that they had offered her “monthly financial support” and “attempted to get her medical help” but that she “refuses conventional treatment”.

The family said they had previously decided not to respond publicly to the allegations, but had chosen to do so after her decision to take legal action.

Sam Altman, 39, is one of the most prominent leaders in the technology sector, and co-founded OpenAI, which is best known for ChatGPT, the artificial intelligence (AI) chatbot, which was launched in 2022.

The billionaire was briefly fired as chief executive in November 2023 by the then board of directors, which accused him of “being not consistently candid in his communications”. Nearly all the workforce threatened to resign and he was hired again to the post the following week.