Sam Altman, chief executive officer of OpenAI Inc., during a media tour of the Stargate AI data center in Abilene, Texas, US, on Tuesday, Sept. 23, 2025. Kyle Grillot | Bloomberg | Getty ImagesOpenAI has finalized a secondary share sale totaling $6.6 billion, allowing current and former employees to sell stock at a record $500 billion valuation, according to a person familiar with the transaction.Bloomberg was first to report that the deal had closed.CNBC reported in August that OpenAI was looki...