GoKawiilGreg Brockman, president of OpenAI, arrives at a federal courthouse as the trial in Elon Musk's lawsuit over OpenAI's for-profit conversion continues, in Oakland, California, U.S., May 6, 2026.
There's a new second-in-command at OpenAI.
Greg Brockman, the company's president, is officially responsible for OpenAI's most important and profitable projects after Fidji Simo stepped down from her role on Thursday due to chronic illness.
Simo, a former Meta executive and ex-CEO of Instacart , served as OpenAI's product and business chief for about a year, focusing the company's roadmap and helping it scale. Simo, who was diagnosed with Postural Orthostatic Tachycardia Syndrome, or POTS, in 2019, took a medical leave in April, and said Thursday that she would transition to a position as a part-time advisor.
Brockman, an OpenAI co-founder, took over product responsibilities during Simo's absence, and will continue to lead those efforts, according to a source familiar with the company's plans who asked not to be named due to confidentiality. Brockman will oversee OpenAI's ChatGPT product business, as well as its go-to-market teams, enterprise teams and compute initiatives, the person said.
"I am deeply grateful for all Fidji has done for OpenAI and to advance our mission, and for the opportunity to have worked alongside her for the past few years," Brockman wrote in a post on X on Friday.
Reporting directly to CEO Sam Altman, Brockman is under pressure to bring in revenue and justify OpenAI's $852 billion valuation, especially as the company gears up for what's expected to be a historic IPO. OpenAI confidentially filed its prospectus with regulators in June, but the company hasn't disclosed when it plans to debut and is reportedly delaying until next year.
OpenAI is also facing increasingly stiff competition from rivals, including Anthropic, Google and Elon Musk's SpaceX , along with a host of cheaper open-weight models primarily out of China.
ChatGPT's market share fell below 50% for the first time in March, according to a report from Sensor Tower, and OpenAI has been aggressively touting its AI coding assistant, Codex, in an effort to win over more users.