Sam Altman, CEO of OpenAI attends the annual Allen and Co. Sun Valley Media and Technology Conference at the Sun Valley Resort in Sun Valley, Idaho, U.S., on July 8, 2025.

David A. Grogan | CNBC

OpenAI is in talks with investors about a potential stock sale at a valuation of roughly $500 billion, according to two sources with knowledge of the matter.

The talks are in early stages and would involve a secondary sale with shares sold by current and former employees, said the people, who asked not to be named because the discussions are confidential. Thrive Capital, an investor in OpenAI, could lead the potential round, the sources said.

Bloomberg was first to report on the latest talks.

OpenAI’s valuation has been on a continuous upswing since the artificial intelligence startup launched ChatGPT in late 2022 and quickly established itself as the leader in generative AI. The company announced a $40 billion funding round in March at a $300 billion, by far the largest amount ever raised by a private tech company.

Last week, OpenAI announced its most recent $8.3 billion tranche tied to that funding round.

OpenAI released two open-weight language models on Tuesday for the first time since it rolled out GPT-2 in 2019. The models aim to serve as lower-cost options that developers and researchers can easily run and customize, OpenAI said.

The company said earlier this week that ChatGPT was about to hit 700 million weekly active users.

OpenAI rival Anthropic, meanwhile, is in talks to secure between $3 billion and $5 billion in new funding led by Iconiq Capital at a potential $170 billion valuation, up from $61.5 billion in March.

CNBC previously reported that OpenAI’s annual recurring revenue is projected to top $20 billion by year-end, up from $10 billion in June.

WATCH: OpenAI releases two new open-weight AI models