Fidji Simo, OpenAI's CEO of Applications and second-in-command executive, announced she is stepping down from her full-time position and transitioning to a part-time advisory role due to a worsening chronic illness on July 9, 2026 [1, 2, 3]. Simo had been on medical leave since April 2026 following a severe exacerbation of Postural Orthostatic Tachycardia Syndrome (POTS), a neuroimmune condition she was diagnosed with in 2019 [4, 2, 5, 6, 7, 8]. She said, "Three months ago, I had to go on medical leave after a severe exacerbation of a chronic illness I’ve lived with for seven years. During that time, it became clear that the road to recovery would be much longer and more complex than I had anticipated—and that I needed to focus on it fully" [4]. She also reflected, "I am only making this decision now because I failed to make it many times before" [7].

Since Simo’s medical leave began, OpenAI President and cofounder Greg Brockman assumed her product responsibilities and was formally assigned to lead product strategy and scaling efforts [4, 2, 9, 5, 6, 7]. Brockman said he is “deeply grateful for all Fidji has done for OpenAI” and her contributions to the company's mission [9].

Simo joined OpenAI in May 2025 after serving as CEO of Instacart, where she led a 2023 IPO, and a decade as an executive at Meta [2, 5, 6, 7, 8]. She has emphasized her belief that AI applications can significantly impact healthcare and medical innovation, and she plans to continue supporting OpenAI’s work in her advisory capacity [1, 7, 8].

OpenAI has seen broader recent executive changes, with COO Brad Lightcap stepping down to focus on special projects and CMO Kate Rouch also resigning due to health reasons [4, 2, 3, 5]. The company confidentially filed for an initial public offering in June 2026 and aims for a public debut in 2027 with a focus on core products like ChatGPT and coding tools [9, 5, 6].

As Simo transitions to part-time advising, OpenAI is poised to continue scaling under Brockman’s product leadership while preparing for its 2027 IPO milestone [9, 5, 6].