Fidji Simo is stepping down from her full-time role at OpenAI, transitioning to part-time advisor after a three-month medical leave, the company confirmed Thursday. Simo joined in May 2025 as CEO of Applications, a newly created No. 2 position reporting directly to Sam Altman that consolidated OpenAI's product and business operations. Her exit lands as OpenAI carries an $852 billion valuation and prepares for an IPO reportedly targeting $1 trillion in 2027.
Simo disclosed in a staff memo that she has lived with a chronic illness for seven years and suffered a severe exacerbation earlier this year. She was diagnosed with Postural Orthostatic Tachycardia Syndrome, or POTS, in 2019, and took medical leave in April 2026 for a relapse of the neuroimmune condition. President Greg Brockman assumed product responsibilities in her absence.
The reporting structure Simo built out was substantial. COO Brad Lightcap, CFO Sarah Friar, and then-CPO Kevin Weil all reported to her, freeing Altman to focus on research, compute, and safety. Weil has since left OpenAI, and Lightcap moved to a special-projects role around the same time Simo went on leave. CMO Kate Rouch also departed in April to focus on cancer recovery.
Key facts
- 01Fidji Simo is stepping down as OpenAI's CEO of Applications and transitioning to a part-time advisor role after three months of medical leave.
- 02Simo was diagnosed with Postural Orthostatic Tachycardia Syndrome (POTS) in 2019 and disclosed a severe relapse of the neuroimmune condition in April 2026.
- 03She joined OpenAI in May 2025 with COO Brad Lightcap, CFO Sarah Friar, and CPO Kevin Weil reporting to her; Weil has since left the company.
- 04OpenAI carries an $852 billion valuation and confidentially filed for an IPO now targeted for 2027 at a reported $1 trillion valuation.
- 05President Greg Brockman absorbed product strategy during Simo's leave and is merging ChatGPT and Codex into a single agentic platform.
Before OpenAI, Simo spent over a decade at Meta running the Facebook app from 2019 to 2021, then took Instacart public as CEO in 2023, breaking the longest tech IPO drought in three decades. She joined OpenAI's board of directors in March 2024 before Altman recruited her to run applications a year later.
In her memo, Simo referenced turning down a full year of medical leave from Meta in 2021, writing that Mark Zuckerberg had told her to play the long game and that she wished she had listened. She said she has spent her tenure at OpenAI postponing medical tests and new therapies to avoid missing work.
The vacancy hits at an awkward moment. OpenAI confidentially filed for an IPO last month, a week after Anthropic did the same, and the company has reorganized aggressively around a smaller set of core products. Thibault Sottiaux was positioned as head of core products including ChatGPT, and OpenAI shut down peripheral bets including Sora as part of the focus strategy.
Brockman's May 2026 reorganization memo laid out four pillars under his control: core product and platform, critical enterprise industries, consumer verticals like health and personal finance, and core infrastructure. The stated goal was to merge ChatGPT and Codex into one agentic experience — a bet on coding tools where OpenAI still trails Anthropic on enterprise adoption.
“invest in a single agentic platform and to merge ChatGPT and Codex into one unified agentic experience for all.”— Greg Brockman, President and co-founder, OpenAI
One internal candidate to expand her portfolio is Denise Dresser, who joined OpenAI as chief revenue officer in December 2025. Dresser previously spent two years as CEO of Slack and 14 years at Salesforce, giving her the enterprise pedigree OpenAI needs as it chases Anthropic in coding and business software.
Simo's exit also lands against OpenAI's escalating equity spending. In April 2025, the month Simo joined, the company shortened its vesting cliff from the industry-standard 12 months to 6 months. In December 2025 it eliminated the cliff entirely, letting equity vest from day one. OpenAI was projected to spend $6 billion on stock-based compensation in 2025 alone, a figure that reflects how aggressively it is defending against poaching from Anthropic and Meta.
ChatGPT's consumer growth cooled late last year and missed internal revenue targets, pushing OpenAI to lean harder into coding and enterprise tools. Simo's mandate had been to scale the applications business into a durable revenue engine ahead of the IPO, and her departure leaves that mandate without an executive owner at a moment when Anthropic is closing the enterprise gap.
Altman said on X he was really sad about the decision and grateful for Simo's contributions and friendship. Simo will remain involved as an advisor but will not carry operational responsibility.
Losing the executive Altman brought in specifically to run the commercial side of OpenAI, months before a $1 trillion IPO attempt, is a real gap. Brockman can hold product strategy in the interim, but the company still needs a full-time operator over applications if the IPO narrative is going to hold up under public-market scrutiny — investors will want to see a named business leader, not a president stretched across every pillar.
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