OpenAI's No. 2 Fidji Simo steps down amid medical leave

Fidji Simo, OpenAI's No. 2 executive and CEO of Applications, is stepping down from her full-time role, the Wall Street Journal reports. In a staff note Thursday, Simo said her ongoing medical leave for a relapse of a neuroimmune condition has proven longer and harder than expected, and she'll transition to a part-time advisory role. Simo joined OpenAI's board in 2024 and came aboard as CEO of Applications in May 2025, a newly created role that consolidated business and product operations under her. She reported directly to Sam Altman and oversaw COO Brad Lightcap, CFO Sarah Friar, and CPO Kevin Weil, allowing Altman to focus on research, compute, and safety. Simo's departure leaves a significant vacuum as OpenAI eyes a potential IPO later this year; she was widely seen as a likely candidate to take on even more responsibility once public.

Simo's announcement lands on a busy news day for OpenAI, which earlier Thursday launched its GPT-5.6 family of models — Sol, Terra, and Luna — and a new agent called ChatGPT Work, designed to handle multistep office tasks. Both releases directly target Anthropic, but ChatGPT's consumer growth has cooled late last year, missing internal revenue targets and pushing the company to lean harder into coding tools where it trails Anthropic. OpenAI's executive ranks appear thin for a company assigned an $852 billion valuation. Beyond Altman, Lightcap, Friar, and co-founder Greg Brockman, its bench includes Denise Dresser, who joined in December as chief revenue officer after two years as CEO of Slack. Dresser may take on a more expansive role given her background.

Simo's departure also comes amid OpenAI's shifting approach to employee equity. In April 2025, the company shortened its vesting cliff from 12 months to 6 months; in December, it eliminated the cliff altogether for new hires, letting equity vest from day one — a move Simo described as allowing employees to 'take risks' without fear of losing equity. The company was projected to spend $6 billion on stock-based compensation in 2025 alone. While none of the recent exits appear tied to compensation, the talent war remains fierce. Simo's transition to part-time advisor underscores a broader challenge for OpenAI: maintaining leadership stability while scaling for an IPO and competing with Anthropic and other AI rivals.