India, Aug. 7 -- OpenAI is in early talks about a potential secondary sale of stock for current and former employees at a valuation of about $500 billion, people aware of the matter said, marking an enormous gain in value for the AI leader. The company is targeting a stock sale in billions of dollars, the people said. OpenAI's previous valuation stood at $300 billion in a $40 billion financing round led by SoftBank Group Corp. P14...