OpenAI executive Fidji Simo steps down for health

OpenAI executive Fidji Simo has announced she is leaving her full-time role at the ChatGPT maker and will become a part-time adviser while she focuses on recovery from a chronic illness.

Simo joined OpenAI in mid-2025 as CEO of Applications and became one of chief executive Sam Altman's top lieutenants. In a post on X, she said three months of medical leave had made clear that her recovery would take far longer and be more complex than expected.

Simo, 40, said she had lived with postural orthostatic tachycardia syndrome, or POTS, since 2019 and had been on medical leave since April because of a severe flare-up. She said she would continue contributing to OpenAI as an adviser.

Altman wrote on X that he was sad about the decision, grateful for Simo's work and friendship, and wished her a speedy recovery.

Before joining OpenAI, Simo led grocery delivery platform Instacart after becoming its CEO in 2021. She previously spent a decade at Meta.