OpenAI IPO Closing Market Cap is a active prediction market event on Polymarket with 7 markets, $1.5M total volume, and $128.5K in liquidity. Key markets: Will OpenAI’s market cap be less than $500B at market close on IPO day?; Will OpenAI’s market cap be between $500B and $750B at market close on IPO day?; Will OpenAI’s market cap be between $750B and $1T at market close on IPO day?.