Welcome to the $4 Trillion Market Cap Club, Microsoft! Are There More Gains for MSFT Stock in Store?

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.

The company’s latest agreement with OpenAI brings significant changes. OpenAI is committed to purchasing an additional $250 billion in Azure services, though Microsoft loses its exclusive computing provider status.

The partnership maintains critical elements, including Microsoft’s rights to frontier models and Azure API exclusivity, until general artificial intelligence is achieved. The restructured OpenAI deal provides clarity on a partnership that had raised investor concerns about growth sustainability and competition from cheaper alternatives.

Microsoft delivered strong fiscal first-quarter results that topped Wall Street expectations. However, the tech stock has pulled back amid concerns about the company’s rising AI expenses.

In fiscal Q1 of 2026 (ended in September), Microsoft reported revenue of $77.67 billion and adjusted earnings of $3.72 per share, above estimates of $75.33 billion and $3.67 per share, respectively.

Azure cloud services drove the top line in Q1, with the segment growing 40%, above estimates of 38.2%. The Intelligent Cloud division reported revenue of $30.9 billion, up 28% year-over-year (YoY).

Microsoft disclosed that its OpenAI investment resulted in a $3.1 billion net income hit during the quarter, equivalent to $0.41 per share. Despite this impact, net income rose to $27.7 billion from $24.67 billion a year earlier.