Microsoft Borrowed $25 Billion to Keep Building Its AI Infrastructure
The company priced ten bond tranches on October 29, with rates running as high as 6.35 percent on the longest-dated debt, signalling how much cash it needs to keep building.
Key points
- Microsoft priced $25 billion in senior unsecured notes (bonds it sells to investors to raise cash) on October 29, 2026, spread across ten tranches with maturities ranging from two years to forty years.
- Fixed rates run from 4.85 percent on two-year paper to 6.35 percent on debt due in 2066, reflecting the long-term commitments Microsoft is taking on.
- Microsoft CFO Amy Hood told analysts on its earnings call that the company had not yet tapped the bond market despite having access to it, making this the first use of that option.
- Oracle announced plans to raise $10 billion in new debt on the same day.
- The offering is expected to close on November 4, 2026, according to the official Microsoft announcement.
Microsoft needs a lot of data centres. The company is racing to keep up with demand from AI labs, meeting requests from OpenAI, Anthropic and other clients whose models run on Microsoft's cloud infrastructure. Building those data centres costs money that even a company of Microsoft's size cannot cover entirely from its own earnings.
So on October 29, 2026, it did something it had been holding in reserve: it borrowed.
The $25 billion bond offering is structured as ten separate tranches. A tranche is simply a slice of a larger debt deal, each with its own repayment date and interest rate. The shortest-dated slices mature in November 2028; the longest runs to November 2066. That forty-year window tells you something about how far out Microsoft is planning its infrastructure bets.
Fixed rates climb with the length of the loan: 4.85 percent for two-year money, up to 6.35 percent for the forty-year slice. Two tranches carry floating rates, meaning the interest cost moves with market benchmarks rather than being locked in.
Why borrow now?
Microsoft's finance chief, Amy Hood, had signalled the move on the company's earnings call. She told analysts the company held a strong credit rating and had not yet used that access. Her precise words: "We're fortunate to have access in the debt markets, given where our ratings are, and we haven't yet tapped that." Microsoft carries a AAA rating from S&P, the credit-rating agency, the highest possible grade, which makes its bonds attractive to the large institutional investors who fund deals like this.
Management has targeted $170 billion in capital expenditure for 2026. That figure covers the chips, servers and land that underpin AI services. It simply exceeds what internal cash flow can cover alone.
Microsoft isn't alone. Amazon and Alphabet have both tapped the bond market for infrastructure projects this year. We covered a comparable move in September, when SoftBank borrowed $11.1 billion to close its $30 billion OpenAI bet, selling bonds in two currencies to fund the final payment on a deal giving it a 13 percent stake. Oracle announced plans to raise $10 billion in new debt on the same day as Microsoft's offering.
What does this mean for ordinary people?
Nothing changes in the short term for people who use Microsoft products. The debt funds the pipes, not the pricing. What it confirms is that AI infrastructure is expensive enough that even the most creditworthy companies need outside money to sustain it.
Watch the interest cost over time. At 6.35 percent on the forty-year notes, the bill runs deep. If the AI demand that justifies this spending doesn't materialise at scale, that debt stays on the books regardless.
Common questions
What is a bond offering and why would a company like Microsoft use one?
A bond is a loan from investors to a company, repaid with interest over a set period. Companies use bonds instead of bank loans when they need very large sums, because the bond market can absorb billions at once in a way that individual banks typically cannot.
Does Microsoft borrowing this much mean it is in financial trouble?
No. Microsoft reported positive free cash flow in its most recent earnings. Borrowing at a AAA credit rating, the safest grade available, is a routine tool for funding big capital projects at a lower interest rate than most companies could access.
Will this affect the cost of Microsoft's AI products for businesses or consumers?
Microsoft said proceeds go toward infrastructure and may also be used for general corporate purposes including debt repayment and share buybacks. No pricing changes have been announced.
