Fidji Simo, who served as CEO of Applications and the second-highest executive at OpenAI, is moving from her full-time position to a part-time advisory role. In a communication to staff on Thursday, Simo explained that her medical leave, which began in April due to a relapse of a neuroimmune condition, had become more prolonged and difficult than originally anticipated.

Simo joined the company in May 2025, reporting directly to Sam Altman. Her role was designed to consolidate product and business operations, meaning that the CPO, CFO, and COO all reported to her while Altman focused on safety, compute, and research. Before joining OpenAI, Simo was the CEO of Instacart from 2021 through its 2023 IPO and spent over ten years at Meta, where she managed the Facebook app.

Her departure occurs during a volatile period for OpenAI's leadership; since April, other executives like Kevin Weil and Kate Rouch have also left. Simo was tasked with expanding the consumer side of the business, though ChatGPT's growth slowed toward the end of last year and missed revenue goals, leading the firm to prioritize coding tools to compete with Anthropic.

The move creates a significant leadership gap for Sam Altman. Simo had been viewed as a key figure for the company's future management, particularly as OpenAI considers a potential initial public offering (IPO).