Sam Altman on the board of OpenAI, nearly four months after the CEO was ousted, and quickly reinstated, from the company he founded. Although Altman had returned as the AI company’s top executive in November, a temporary board oversaw his return and the subsequent investigation into his conduct.

That investigation is now complete, according to the company, which added three new members to its board of directors. The additions include: Instacart CEO and former Meta executive Fidji Simo, former Sony executive Nicole Seligman and Dr. Sue Desmond-Hellmann, former CEO of the Bill and Melinda Gates Foundation. Salesforce co-CEO Bret Taylor, economist Larry Summers and OpenAI co-founder Greg Brockman, who served on the temporary three-seat board, will remain in their positions with Taylor continuing as chair.

The announcement caps off a tumultuous several months for the AI company, which by Altman’s abrupt ouster last fall.

On Friday, OpenAI also published a summary of the findings from WilmerHale, a law firm that the company’s board retained in December 2023 to conduct an independent investigation into the events that led to Altman’s firing. Despite that, however, we’re no closer to finding out exactly why Altman, who rejoined the company as CEO within five days, was fired to begin with.

“WilmerHale [found] that the prior Board’s decision did not arise out of concerns regarding product safety or security, the pace of development, OpenAI’s finances, or its statements to investors, customers, or business partners,” the summary said. “Instead, it was a consequence of a breakdown in the relationship and loss of trust between the prior Board and Mr. Altman.” WilmerHale also concluded that OpenAI’s previous board fired Altman abruptly without giving notice to “key stakeholders”, and without giving Altman an opportunity to respond to its concerns.

To come to this conclusion, the firm reviewed more than 30,000 documents and conducted dozens of interviews with OpenAI staffers including previous board members over the last few months.