OpenAI has become the world's most valuable startup, surpassing Elon Musk's SpaceX, Bloomberg reported Thursday. The milestone comes after current and former OpenAI employees sold about $6.6 billion worth of stock to investors in a secondary sale.
Earlier this year, the ChatGPT maker was valued at around $300 billion, compared to SpaceX's $400 billion. However, the latest transaction has pushed the company's valuation past $500 billion, according to a person familiar with the deal.
The price increase comes at a time when OpenAI has been in talks with Microsoft to restructure into a more traditional for-profit entity.
Microsoft has been one of OpenAI's closest partners and biggest supporters, investing billions of dollars in the company as it expands its AI infrastructure. Microsoft CEO Satya Nadella expressed concern last month that advances in AI could make Microsoft's core businesses obsolete, as the company has already cut more than 15,000 jobs this year as part of a broader reorganization.
OpenAI was founded in 2015 as a non-profit research lab with the stated goal of developing artificial intelligence "for the benefit of humanity as a whole."
The group rose to prominence after launching ChatGPT in 2022, which was quickly adopted by millions of users. Since then, the group has launched a series of increasingly advanced models, including GPT-5 in August 2025, while signing large-scale infrastructure agreements with partners such as Oracle and SK Hynix.
Musk was one of the company's co-founders, but resigned from the board in 2018. He has since accused OpenAI of abandoning its original non-profit mission after taking billions of dollars in Microsoft funding.
