OpenAI is in early discussions to organise a secondary share sale that would let current and former employees sell part of their equity at a valuation of roughly $500 billion, according to people familiar with the matter. The mooted price tag would lift the San-Francisco-based artificial-intelligence developer’s worth by about two-thirds from the $300 billion level reached in April and would eclipse the latest private valuation of Elon Musk’s SpaceX, estimated at about $350 billion. Existing backer Thrive Capital is among the investors sounding out the company about purchasing the stock, while SoftBank and other large funds also hold stakes. Past tenders have allowed OpenAI staff to cash out between $2 million and $10 million apiece, and the new process is expected to run along similar lines, giving employees fresh liquidity without diluting the company’s overall share count. A half-trillion valuation would underscore the intense investor appetite for generative-AI leaders. OpenAI last week raised $8.3 billion of fresh capital and said its flagship chatbot, ChatGPT, is on track to reach 700 million weekly active users. Rival Anthropic is separately in talks for financing that could value it at about $170 billion, highlighting the accelerating capital requirements across the sector. The prospective share sale comes as OpenAI prepares to unveil GPT-5, the next iteration of its large language model, during a livestream scheduled for Thursday at 10 a.m. Pacific time. The launch, alongside the potential tender offer, would further cement the company’s position at the forefront of the global artificial-intelligence boom.