ISTANBUL

OpenAI finalized a $6.6 billion secondary share sale, enabling current and former workers to sell stock for a record valuation of $500 billion, CNBC reported Thursday, citing a person familiar with the matter.

Thrive Capital, SoftBank, Dragoneer Investment Group, Abu Dhabi's MGX, and T. Rowe Price were among the investors in OpenAI's proposed secondary share sale in August, which was at a $500 billion valuation.

Only around two-thirds of the $10.3 billion in shares that OpenAI had approved for sale actually changed hands, despite the company's initial $6 billion goal having been raised.

Even with a $500 billion valuation, up significantly from $300 billion earlier this year, the person informed on internal conversations said that lesser participation is being seen internally as a vote of confidence in the company's long-term prospects and an indication that investor demand is still robust.

In September, the offer was made to qualified current and past workers, anyone who had owned shares for more than two years was entitled to participate.

After a $1.5 billion agreement with SoftBank in November, this share sale is OpenAI's second significant tender offer in less than a year.

With this most recent deal, OpenAI has surpassed SpaceX's $456 billion value to become the most valuable privately owned firm in the world.

The transaction comes as the race for AI talent heats up. In an effort to attract prominent academics, Meta, in particular, is said to have offered nine-figure remuneration packages.

OpenAI is part of an expanding group of well-known startups that use secondary sales to let staff members cash out while remaining anonymous, such as SpaceX, Stripe, and Databricks.