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Microsoft (MSFT) became the second U.S. company to join the exclusive $4 trillion market cap club on Tuesday, riding a 4% surge after restructuring its OpenAI partnership. The software giant now values its stake in the AI startup at roughly $135 billion, representing about 27% ownership on a fully diluted basis.
The milestone comes as Microsoft and Apple (AAPL) raced toward the $4 trillion threshold, with Apple needing to close above $269.54 to claim its spot. Nvidia (NVDA) reached this valuation for the first time back in July and now trades above $5 trillion. The chipmaker moved much faster between trillion-dollar marks than its peers, taking just 66 trading days to jump from $2 trillion to $3 trillion.