Fidji Simo Steps Down as OpenAI's No. 2 After Three Months of Medical Leave

OpenAI has lost its second-in-command. Fidji Simo, the company's CEO of Applications, said on Thursday, July 9 that she is stepping out of her full-time role and moving to a part-time advisory position, ending a three-month medical leave that had already left the commercial side of OpenAI without its leader.

The job she held

Simo arrived from Instacart, where she was chief executive from 2021 and led the company's 2023 IPO, after a decade at Meta, where she spent her final years running the Facebook app. She joined OpenAI's board in 2024, then in May 2025 took a role created for her: consolidating product and business operations under a single executive reporting to Sam Altman. COO Brad Lightcap, CFO Sarah Friar and then-chief product officer Kevin Weil reported through her.

The leave

On April 3, Simo disclosed a relapse of a neuroimmune condition — she has said publicly she was diagnosed with POTS, or postural orthostatic tachycardia syndrome, in 2019 — and stepped back for what was expected to be several weeks. It ran roughly three months, with president Greg Brockman covering product responsibilities in the interim. "I have decided to leave my full-time role at OpenAI and transition to being a part-time advisor," Simo wrote on Thursday, adding that she was "only making this decision now because I failed to make it many times before." She has said she once turned down a full year of medical leave offered by Meta.

Altman's response

Altman's post on X was unusually plain: "i am really sad about this and very grateful for all fidji has done for openai, and even grateful for her friendship and who she is as a person. we all wish her the best for a speedy recovery. this sucks."

The hole she leaves

OpenAI has named no successor and is searching. Where Lightcap and Friar now report is unclear; Weil left the company in April. Denise Dresser, the chief revenue officer who joined in December 2025 after two years running Slack, absorbed some commercial duties in an April reshuffle but has not been described as taking Simo's full scope. That reshuffle also moved Lightcap off the COO seat to lead special projects, and CMO Kate Rouch stepped down the same day for cancer recovery. The vacancy arrives as OpenAI ships enterprise products at speed and weighs a public offering — a moment when the executive who owned revenue and product was seen as a candidate for more, not less.