OpenAI is reportedly in talks about a stock sale that would push its market valuation to half a trillion dollars

ChatGPT maker OpenAI is in talks with investors on a stock sale that could value it at $500 billion, Bloomberg reported on Tuesday. The deal would let employees sell shares and could make the company the world's most valuable private tech firm, surpassing Elon Musk's $400 billion-valued SpaceX.

The talks are reportedly in the early stages, but a source said all OpenAI's current investors, including New York-based firm Thrive Capital, are involved. As OpenAI isn't publicly traded, the sale would allow current and former staff to sell shares directly to investors. The final valuation will depend on demand.

Sources claimed OpenAI is looking to tap strong investor interest to give staff a chance to cash out and benefit from the company's growth. The report comes after OpenAI's recent $40 billion funding round led by Japan's SoftBank, which valued the company at $300 billion. Last week, the firm raised $8.3 billion from that round, with demand reportedly five times higher than available shares. Sources said investor interest means the new share sale could be much bigger than the $1.5 billion one OpenAI did late last year.

OpenAI and Thrive Capital declined to comment.

The possible sale comes during an AI boom, with investors pouring money into leading firms. Public filings show Meta, Microsoft, Amazon, and Alphabet spent tens of billions on AI this year and plan to invest over $400 billion in 2026. Experts say spending could climb higher under US President Donald Trump's 'Big Beautiful Bill', which offers tax breaks for companies that frontload investments, freeing up cash for AI projects.

Big US startups often let employees sell shares to reward them, keep them on board, and draw in new investors. OpenAI is one of the most influential players in AI research but faces stiff competition. Since launching ChatGPT in late 2022, its annual subscription revenue has grown to $12 billion, while rival Anthropic has quadrupled its revenue this year to $4 billion.

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To stay ahead, OpenAI this week released new "open weight" models for developers to freely customize and is preparing to launch its much-anticipated GPT 5 model later this month.