Fidji Simo, Sam Altman’s second-in-command at OpenAI, is stepping down from her full-time role after an extended medical leave, as the company prepares for its IPO. Simo announced on X that her neuroimmune condition had worsened and her recovery timeline would be longer than anticipated. Her departure follows a series of high-profile exits, including former COO Brad Lightcap, CMO Kate Rouch, and research head Kevin Weil. In an internal note Thursday, Simo said her product and business duties would be divided among President Greg Brockman, CFO Sarah Friar, and Chief Strategy Officer Jason Kwon. Simo was key in ramping up OpenAI’s focus on business-oriented coding tools after rival Anthropic pulled ahead, led early efforts to create a coding-focused “superapp” that launched Friday, and cut costly side projects like video-generator app Sora. She will become a part-time adviser. Simo had been tasked with accelerating ChatGPT’s growth, introducing ads and features such as health advice, and was set to take on larger roles after the IPO, expected as soon as this year. She joined last August and took medical leave in April.