Microsoft is back in the $4 trillion club. The company closed at a market capitalization of $4.02 trillion on October 12, 2026, its first sustained stay above that line since October 29, 2025.
The rebound matters because it answers a question that has hung over the entire tech sector. Investors had been asking whether all that money poured into artificial intelligence would ever pay off. At least for Microsoft, the market now seems to think the answer is yes.
How Microsoft got its groove back
Microsoft shares have recovered by more than 50% from their lows in June 2026.
The engine behind the rally is Azure, Microsoft’s cloud computing business. Azure revenue grew 43% year over year in the June quarter.
Management expects that pace to pick up further. Guidance points to growth of 45% in constant currency, a measure that strips out the effect of exchange rate swings.
Microsoft’s remaining performance obligations, or RPO, for cloud and AI contracts reached $678 billion, an increase of 84%.
RPO is essentially revenue that customers have signed up for but Microsoft has not yet recognized. For investors worried about AI spending, that figure carried a lot of weight. It suggests enterprises are committing real money to AI infrastructure, not just experimenting with pilot projects.
A chip of its own
Microsoft also used the same day to make a hardware statement. The company unveiled its Azure Maia 300 AI chip at the OCP Global Summit on October 12, 2026.
The chip is expected to help Microsoft reduce its dependence on graphics chips from Nvidia and AMD. It is also expected to improve efficiency inside the company’s data centers.
The road from $4 trillion and back
Microsoft first crossed the $4 trillion threshold in July 2025. At the time, it became only the second company in the world to reach that valuation.
The stock slipped after that peak as concerns mounted over the profitability of AI spending and the trajectory of cloud growth.
Even after reclaiming the milestone, Microsoft now ranks as the fourth largest US company by market capitalization, behind Nvidia, Apple, and Amazon.
What this means for investors and the tech sector
Contracted demand, visible in that $678 billion backlog, appears to be validating the company’s heavy spending on cloud and AI infrastructure.
There are still risks. Guidance for 45% Azure growth is a forecast, not a guarantee. A backlog also has to be converted into recognized revenue over time.
Key items to watch include whether Azure hits its constant currency growth target, how quickly the RPO figure translates into reported sales, and whether the Maia 300 meaningfully improves data center economics.
Disclosure: This article was edited by Diego Almada Lopez. For more information on how we create and review content, see our Editorial Policy.