Microsoft eyes a $25B+ bond sale, its first of the kind since 2017

Microsoft is seeking to raise at least $25 billion in its first US investment-grade bond sale since 2017, to pay for AI-related capital spending, according to Bloomberg’s report, relayed by Techmeme. A preliminary SEC filing dated October 29, 2026 confirms the offering, but not its size.

A ten-part note offering, with the size left blank

Bloomberg, citing people familiar with the matter, says the company wants to raise at least $25 billion. It was last in this market in 2017, when it raised $17 billion. Microsoft has not publicly confirmed the amount.

What the company has put on record is a preliminary prospectus supplement (form 424B2), filed with the SEC and marked “Subject to Completion, Dated October 29, 2026”. It describes ten series of senior notes: two floating-rate series, priced at compounded SOFR plus a margin that resets quarterly, and eight fixed-rate series that pay interest twice a year.

The notes are issued under a base indenture dated May 18, 2009. In this preliminary version the total principal, the maturity dates, the coupons and the pricing date are all blank, so the $25 billion figure rests on Bloomberg’s sources alone. Those numbers normally appear when the deal is priced.

Proceeds are not tied to AI in the filing

The filing is broader than the report. It says the net proceeds will go to “general corporate purposes”, a category it says may include working capital, capital expenditures, share repurchases, acquisitions and repaying existing debt. It does not mention AI or data centers. The link to AI spending comes from Bloomberg’s sources, not from the document.

That gap matters for readers who want to know what the money will build. Until Microsoft or the final prospectus says more, the AI purpose is a reported motive, not a stated commitment.

Track record: Big tech turns to debt as cash flow tightens

Microsoft is joining a pattern rather than starting one. Within the same week, Techmeme reported, via Bloomberg, that Meta’s $25B share sale was oversubscribed five times as the company seeks $98B for AI spending. Search coverage of earlier deals points the same way: Oracle sold about $25 billion of bonds in February 2026, and Alphabet and Amazon have each been reported seeking $25 billion in bond sales, though those reports were not checked against filings for this article.

The strain is visible in earnings. Our report on Alphabet’s quarter found that Google’s cloud sales doubled to $30.7B, but spending turned its cash flow negative. Borrowing in the bond market is one way to bridge that kind of gap without issuing shares.

Microsoft’s own history is the sharpest contrast. Its last comparable sale, in 2017, raised $17 billion, and the reported new target is at least roughly 1.5 times that. The company has also gone more than nine years without a dollar bond sale of this kind, according to Bloomberg.

What the reports leave open

Several basics are still unknown. The final size could differ from the reported minimum. The split between floating and fixed notes, the maturities and the yields will only become clear at pricing, and demand from investors is not yet known. Microsoft has also not said how much of the money will go to data centers and chips versus other uses.

For most readers there is nothing to do: the notes are sold to institutional buyers through banks, and the filing is a step in a process that ends with pricing. What the filing does show is that one of the largest software companies is ready to take on debt on a scale it has not used in years, and that the AI buildout is now being funded with borrowed money as well as operating cash.