San Francisco-based OpenAI Chief Executive Officer of Applications Fidji Simo has stepped down from her full-time executive position, transitioning to a part-time advisory role. The announcement, confirmed on Thursday, concludes three months of medical leave as Simo manages postural tachycardia syndrome (POTS), a chronic neurological disorder diagnosed in 2019 that causes severe dizziness, elevated heart rates, and fainting. Simo stated that her recovery has proven more complex than anticipated, requiring her full attention and prompting the leadership adjustment. Simo joined OpenAI in 2025 after serving as chief executive of Instacart, where she successfully guided the company through its initial public offering. Her tenure at the artificial intelligence developer was defined by a strategic pivot toward commercialization and enterprise revenue generation. Tasked with translating foundational research into scalable business operations, Simo redirected corporate focus away from speculative consumer projects. The company subsequently discontinued the Sora video generation platform and reallocated engineering resources toward developer-centric products, notably the Codex coding assistant. This recalibration was designed to capture lucrative enterprise contracts and directly compete with rival Anthropic as OpenAI prepares for a potential initial public offering and trillion-dollar valuation. Throughout her leadership, Simo conducted extensive internal reviews to maintain OpenAI research-oriented culture amid rapid corporate scaling. She enforced disciplined capital allocation, publicly cautioning executive teams against diverting resources into non-core initiatives. Her operational strategy coincided with OpenAI aggressive push to secure high-value corporate partnerships and expand compute infrastructure. Chief Executive Sam Altman, who oversees foundational research and infrastructure, publicly praised Simo contributions. In a brief statement, Altman expressed gratitude for her strategic leadership and personal friendship, while extending wishes for her continued recovery. Co-president Greg Brockman also acknowledged Simo ongoing advisory commitment, ensuring uninterrupted execution of OpenAI product roadmap. The transition occurs at a critical growth juncture for the company. With Simo moving to a reduced-capacity advisory capacity, day-to-day product strategy and enterprise commercialization will remain under current executive leadership. OpenAI strategic emphasis on developer ecosystems, API infrastructure, and industry-specific AI applications will proceed unchanged, preserving the competitive positioning Simo helped establish. Her departure underscores the physical demands of leading rapid-scale technology firms, even as OpenAI advances toward public market readiness and sustained industry dominance.