# OpenAI Loses No. 2 Exec & Head of Safety > Source: [https://icharles.com/articles/openai-fidji-simo-safety-departure](https://icharles.com/articles/openai-fidji-simo-safety-departure) (canonical) > Author: iCharles News — iCharles, https://icharles.com > Published: 2026-07-12 ## TL;DR OpenAI's two most prominent departures landed on the same day. Fidji Simo, the company's No. 2 executive and CEO of Applications, is stepping down from her full-time role after a medical leave for a neuroimmune condition proved longer than expected. Separately, Johannes Heidecke, OpenAI's head of safety systems, told staff he is leaving following a reorganization that merged the safety and research teams under VP Mia Glaese. ## What happened at OpenAI on July 9, 2026? OpenAI lost two senior leaders on the same day. Fidji Simo, the company's CEO of Applications and No. 2 executive, announced she is stepping down from her full-time role. Hours earlier, Johannes Heidecke, OpenAI's head of safety systems, told staff he is leaving after a restructuring merged his team with research. Both departures landed as OpenAI also launched its new GPT-5.6 family of models — Sol, Terra, and Luna — alongside a new agent called ChatGPT Work, [according to TechCrunch](https://techcrunch.com/2026/07/09/fidji-simo-steps-down-from-openais-no-2-role/). --- ## Why is Fidji Simo leaving OpenAI? Simo is stepping down for health reasons. In a staff note on Thursday, she said her medical leave has proven longer and harder than expected. She first disclosed the issue in April, when she announced a relapse of a neuroimmune condition. Rather than return full-time, Simo will move to a part-time advisory role. Sam Altman responded on X: "i am really sad about this and very grateful for all fidji has done for openai, and even grateful for her friendship and who she is as a person. we all wish her the best for a speedy recovery. this sucks." --- ## Who was Fidji Simo at OpenAI? **Fidji Simo** is the executive who joined OpenAI in May 2025 as CEO of Applications — a newly created role that consolidated the company's business and product operations, reporting directly to Sam Altman. When she joined, COO Brad Lightcap, CFO Sarah Friar, and CPO Kevin Weil all began reporting to her. Altman stepped back to focus on research, compute, and safety. Simo came to OpenAI from Instacart, where she had been CEO since 2021 and led the company through its 2023 IPO. Before that, she spent over a decade at Meta, including running the Facebook app. She had also joined OpenAI's board of directors in 2024, before taking the operational role. --- ## What does Simo's exit mean for OpenAI's leadership? Here's what we know so far: OpenAI's executive bench is thin for a company valued at $852 billion. Active senior leaders include Altman, Lightcap, Friar, and co-founder Greg Brockman, who was overseeing product strategy while Simo was on leave. Chief Revenue Officer Denise Dresser, who joined in December, is also part of the core team. Kevin Weil, who had reported to Simo, has already left the company. CMO Kate Rouch also departed earlier this year. Simo's exit leaves Altman without a clear No. 2 as OpenAI eyes a possible IPO, [the Wall Street Journal reports](https://www.wsj.com/tech/openai-top-executive-fidji-simo-to-step-down-c3daca47). **Key leadership changes at OpenAI in 2026:** - **Fidji Simo** — stepping down from CEO of Applications; moving to part-time advisory role - **Johannes Heidecke** — departing as head of safety systems - **Kevin Weil** — previously left as CPO - **Kate Rouch** — previously left as CMO - **Brad Lightcap** — moved to a "special projects" role in April - **Mia Glaese** — promoted to VP of research and safety --- ## Why is OpenAI's safety head Johannes Heidecke leaving? Heidecke's exit follows a reorganization of OpenAI's safety and research teams. Chief research officer Mark Chen announced in a memo to staff that safety teams will now report to Mia Glaese, who takes on an expanded title: VP of research and safety. Saachi Jain, who previously led safety teams, becomes interim head of safety systems, reporting to Glaese. Chen wrote in the memo: "The demands on safety continue to increase — we are training models at a much faster cadence, and release cycles have come down greatly in turn. As a result, we have bigger coordination challenges around safety today than ever before." Heidecke joined OpenAI in 2021 as an AI safety analyst. He became head of safety systems in 2024, after the previous head, Lilian Weng, left to co-found Thinking Machines Lab, [as WIRED reported](https://www.wired.com/story/openai-head-of-safety-leaving/). --- ## What is the new structure of OpenAI's safety team? The reorganization puts safety directly under research leadership. Mia Glaese, previously VP of research and head of alignment, now oversees both research and safety. Saachi Jain steps in as interim head of safety systems under Glaese. Chen framed the move as a push for tighter coordination: "It's important that our safety work is integrated with frontier-model development, with an earlier and more direct role in shaping key model, product, and launch decisions." **Before and after the restructuring:** | Role | Before | After | |---|---|---| | Head of safety systems | Johannes Heidecke | Saachi Jain (interim) | | Safety team reports to | Head of safety systems | VP of research and safety | | VP of research and safety | Not combined | Mia Glaese | --- ## How does this connect to OpenAI's broader business pressures? ChatGPT's growth cooled late last year, missing internal revenue targets. That pushed OpenAI to lean harder into coding tools — an area where it has been trailing Anthropic. Simo had been primarily focused on growing OpenAI's consumer business. OpenAI has also been spending aggressively to retain staff. The company was projected to spend $6 billion on stock-based compensation in 2025 alone. In December, OpenAI eliminated its equity vesting cliff for new hires, letting stock vest from day one. Simo had described that move internally as a way to let employees "take risks" without fear of losing equity if let go early. These executive moves come as other major AI players are also making big bets — [Anthropic recently leased](/articles/anthropic-nyc-office-terawulf-deal) 466,000 square feet of New York office space, and [Amazon raised](/articles/amazon-25-billion-bond-sale-ai) a $25 billion bond sale to fund AI spending. The [AI talent war](/articles/spacex-nasdaq-100-inclusion-july-2026) is reshaping how companies structure compensation across the sector. The most confirmed next step: Mia Glaese now leads both research and safety at OpenAI, with Saachi Jain serving as interim head of safety systems reporting to her. --- ## Frequently asked questions **Why did Fidji Simo leave OpenAI?** Simo stepped down from her full-time role as CEO of Applications because her medical leave for a neuroimmune condition proved longer and harder than expected. She first disclosed the health issue in April 2026. Rather than return full-time, she will transition to a part-time advisory role. Sam Altman publicly expressed sadness about her departure on X. **Who is replacing Fidji Simo at OpenAI?** No direct replacement has been named. OpenAI's active senior leadership includes Sam Altman, COO Brad Lightcap, CFO Sarah Friar, co-founder Greg Brockman, and Chief Revenue Officer Denise Dresser. Dresser joined in December and previously served as CEO of Slack. No successor to Simo's CEO of Applications role has been announced. **Why did OpenAI's head of safety Johannes Heidecke leave?** Heidecke's departure followed a reorganization that merged OpenAI's safety and research teams. Chief research officer Mark Chen announced that safety teams would now report to Mia Glaese as VP of research and safety. Heidecke had held the head of safety systems role since 2024, after joining OpenAI in 2021 as an AI safety analyst. **Who is Mia Glaese and what is her new role at OpenAI?** Mia Glaese is OpenAI's newly appointed VP of research and safety. She previously served as VP of research and head of alignment. Following the restructuring announced by chief research officer Mark Chen, she now oversees both the research and safety organizations. Saachi Jain reports to her as interim head of safety systems. **What is OpenAI's current valuation and IPO status?** OpenAI was most recently assigned an $852 billion valuation, according to TechCrunch. The company is eyeing a possible IPO, and Simo had been widely seen as a candidate to take on more responsibility once OpenAI went public. Her departure creates a leadership gap at a critical moment in the company's path toward a public offering. ## Frequently asked questions **Why did Fidji Simo leave OpenAI?** Simo stepped down from her full-time role as CEO of Applications because her medical leave for a neuroimmune condition proved longer and harder than expected. She first disclosed the health issue in April 2026. Rather than return full-time, she will transition to a part-time advisory role. Sam Altman publicly expressed sadness about her departure on X. **Who is replacing Fidji Simo at OpenAI?** No direct replacement has been named. OpenAI's active senior leadership includes Sam Altman, COO Brad Lightcap, CFO Sarah Friar, co-founder Greg Brockman, and Chief Revenue Officer Denise Dresser. Dresser joined in December and previously served as CEO of Slack. No successor to Simo's CEO of Applications role has been announced. **Why did OpenAI's head of safety Johannes Heidecke leave?** Heidecke's departure followed a reorganization that merged OpenAI's safety and research teams. Chief research officer Mark Chen announced that safety teams would now report to Mia Glaese as VP of research and safety. Heidecke had held the head of safety systems role since 2024, after joining OpenAI in 2021 as an AI safety analyst. **Who is Mia Glaese and what is her new role at OpenAI?** Mia Glaese is OpenAI's newly appointed VP of research and safety. She previously served as VP of research and head of alignment. Following the restructuring announced by chief research officer Mark Chen, she now oversees both the research and safety organizations. Saachi Jain reports to her as interim head of safety systems. **What is OpenAI's current valuation and IPO status?** OpenAI was most recently assigned an $852 billion valuation, according to TechCrunch. The company is eyeing a possible IPO, and Simo had been widely seen as a candidate to take on more responsibility once OpenAI went public. Her departure creates a leadership gap at a critical moment in the company's path toward a public offering.