Microsoft Pays Cash For AI. CoreWeave Borrows.
The AI build-out is running partly on borrowed money, and borrowed money isn’t cheap: the 10-year Treasury yields 5.1%, with inflation back at 3.7%. Two AI companies show what that means for shareholders. Microsoft closed on Oct 19 just 1.8% below its 52-week high, set on Oct 13. CoreWeave is 56.3% below its own, set on Oct 29, 2025. Same AI boom, so why the gap?
Both live off AI. Microsoft is one of its biggest buyers: its capital spending, mostly chips and data centers, came to $115.9 billion in the fiscal year to June 30, 2026. CoreWeave is a builder. It rents out Nvidia chips to AI labs and tech companies, and pays for them largely with debt.
Here’s the odd part. CoreWeave now owes almost as much as Microsoft: $51.6 billion of total debt against $56.8 billion. Microsoft’s revenue is 44 times bigger.
A plain word: this is general education using two real companies as examples. It isn’t advice, and it isn’t a call to buy or sell either stock.
How Much Does Each One Owe?
Microsoft holds $19.8 billion more cash and short-term investments than debt. Over the twelve months to June 30, 2026, its operating income covered its interest bill 51 times.
CoreWeave’s debt went from $6.3 billion to $51.6 billion in 21 months, including leases (about $35 billion excluding leases). Net of cash, it owes $46.1 billion, more than its $33.7 billion stock market value. And it ran an operating loss, so operating income covered none of its $1.9 billion of interest.
| Figure | Microsoft | CoreWeave | Basis |
|---|---|---|---|
| Net cash (net debt) | $19.8B | ($46.1B) | June 30, 2026; total debt (CoreWeave’s includes leases) |
| Operating income ÷ interest | 51× | Operating loss | twelve months to June 30, 2026 |
| Free cash flow | $67.0B | −$13.7B | twelve months to June 30, 2026 |
| Distance from 52-week high | −1.8% | −56.3% | Oct 19, 2026 close |
Microsoft’s twelve months are its fiscal year. Net cash or debt is cash and short-term investments minus total debt; CoreWeave’s debt includes $16.5B of leases.
How Does Microsoft Pay For AI?
Out of pocket. Its business brought in $182.9 billion of cash in the fiscal year, up 34%. Capital spending rose 80% and still used only 63% of that cash.
Why spend so much? “Customer demand continues to exceed available capacity,” finance chief Amy Hood said on the Jul 29 call. She expects capital spending to grow again in the year to June 2027, and free cash flow to stay positive.
And CoreWeave?
It borrows to build. Revenue more than doubled, to $7.6 billion over the twelve months to June 30, 2026, and the business brought in $6.9 billion of cash. But it spent three times that, $20.6 billion, on chips and data-center gear. The $13.7 billion gap came mostly from lenders, with some from new shares. Its $5.5 billion of cash covers about five months of that.
The bill is rising. Interest ate about a quarter of revenue, and CoreWeave plans $35 billion to $39 billion of capital spending this year. In September it priced $3.7 billion of convertible notes. On Oct 15, yields on its 2031 bonds topped 15%, CNBC reported.
What Happens When The Buyer Builds Its Own?
Microsoft rents from the builders too. In August, IREN, another AI data-center builder, said Microsoft had accepted Horizon 1, capacity built for IREN’s AI cloud contract with Microsoft.
But the buyer has choices. On Oct 12, Microsoft said it intends to make its own Maia chips its main architecture for running AI models, CNBC reported; Satya Nadella says Maia 200 gives 30% better performance per dollar than the latest hardware in its fleet. And on Oct 18, Reuters, citing the Telegraph, reported that Microsoft had pulled out of a UK data-center deal with Nscale.
Bernstein analysts warned in March that CoreWeave’s business could be cannibalized as Big Tech customers build their own. As we read it, that’s the gap in one line: Microsoft can build, rent or wait. CoreWeave needs its customers to keep renting.
Holding a lot of one AI stock? See how to put a floor under a large position.
Why Did The Stocks Split So Far?
Not sales. As we read it, what fell at CoreWeave is the price investors will pay for growth funded with debt, as its borrowing costs climbed: the multiple, not the business.
Microsoft’s gain this year is earnings. Its twelve-month net income rose 12% between the December and June quarter-ends, and its price-to-earnings multiple slipped from 30.1 at the end of December to 29.6 on Oct 19.
How Each Story Unfolded
Microsoft
1 · Demand outruns supply Capacity short of what customers want.
2 · It builds from cash $115.9B of capex, 63% of operating cash.
3 · Cash left over $67.0B of free cash flow.
4 · Chips in-house Maia to run its AI models.
CoreWeave
1 · Contracts pile up $104.2B backlog at June 30.
2 · It borrows to build Debt from $6.3B to $51.6B.
3 · Interest bites About a quarter of revenue.
4 · It needs more $35–39B capex plan vs $5.5B of cash.
5 · Lenders want more 2031 bond yields topped 15% on Oct 15.
Notice where CoreWeave’s chain ends: with its lenders, not its customers. Apart from loans that pay down as contracts pay, and vendor financing, nothing comes due until 2029, it says. The question is what the next dollar costs.
What Would Flip The Call?
For Microsoft, the payoff. Capital spending rose 80% while free cash flow fell 6%. If AI demand stalls, Microsoft is left holding capacity, but not owing for it.
For CoreWeave, prices and customers. It says it is signing new short contracts at about $40 million of yearly revenue per megawatt, and added over $25 billion of commitments early in the third quarter. If that cash arrives on time, lenders may relax.
What To Watch
CoreWeave’s 2031 bonds. Yields topped 15% on Oct 15, 2026. A fall toward the 9.625% it paid on new notes in June would say the fear has passed.
CoreWeave’s cash. $5.5 billion at June 30, 2026, against $35 billion to $39 billion of planned spending this year. Watch the size and price of each raise.
Microsoft’s spending. Over $50 billion guided for the July-to-September quarter, its first of fiscal 2027, after an accounting change that moves some future data-center leases out of capital spending. More Maia, we think, means less need for rented chips.
The Bottom Line
This is cash vs debt in its plainest form, and it isn’t a one-off: across five pairs of rivals in different industries, the company with the stronger balance sheet sits closer to its 52-week high. Both sell AI computing in the end. One pays from a business that brought in $182.9 billion of cash last fiscal year. The other borrows against contracts.
And the biggest buyers of AI computing can also build it themselves. Microsoft can choose. CoreWeave can’t.
What If Much Of Your Wealth Rides On One AI Stock?
The same AI boom lifted both stocks, and only one is still near its high. If an AI winner has grown into a large part of your wealth, a sharp fall can hurt your whole plan, and selling to spread the money out can bring a large tax bill. There are ways in between: putting a floor under the position, paid for by giving up some of the upside, and moving out of it over time with less tax. Our partner advisory firm offers a free strategy review of how that would work for your holdings.