How Much of U.S. Growth Now Rides on the AI Buildout?

Three of the largest American companies reported earnings this week, and each spent the quarter building the same thing. Microsoft and Alphabet are pouring record sums into data centers, chips, and the power to run them, and Amazon reports Thursday afternoon. The scale has grown large enough that economists now argue over how much of the country’s growth it accounts for. Apollo’s chief economist, Torsten Slok, estimates that AI-related activity makes up about half of U.S. economic growth in 2026. ING’s James Knightley puts the figure nearer a third. Either way, the number is large. And it is rising. That has turned a corporate spending cycle into a question about the whole economy: if the buildout is doing this much of the lifting, what is the expansion standing on? This week’s results spoke to that from both sides at once.

Azure grew 48% and Google’s cloud revenue doubled

The case for the spending starts with demand that is still accelerating. Microsoft said Azure revenue grew 48% in its latest quarter, above the 44% to 45% range management had guided to, and disclosed the cloud unit’s revenue in dollars for the first time. Total revenue reached $92.3 billion, up 19%. Alphabet’s Google Cloud revenue more than doubled from a year earlier, to $30.7 billion, past what analysts had modeled. The demand is real. These are booked sales growing at rates most businesses this size never see, well past the pilot stage. The firms funding the buildout also generate enormous cash and carry little debt against it, part of why the International Monetary Fund, even while flagging risk, judged an abrupt dot-com-style collapse less likely this time. If customers keep signing up for computing at these rates, the capital going into it reads as a company building ahead of orders it already holds.

Alphabet spent $51 billion and still burned cash

The same reports carry the opposite reading. Alphabet’s capital spending hit $51.4 billion in the quarter, up from $24 billion a year earlier, and its free cash flow ran to negative $9.1 billion, deeper than the quarter before. The company told investors to expect about $200 billion in capital spending this year, rising toward $300 billion next year. Microsoft spent $45.2 billion in its quarter and guided to about $170 billion for the calendar year. The pace is the problem. Spending faster than the cash coming in is the crux of the worry, and the depreciation charges on all that hardware arrive later, as the equipment ages. Concentration deepens the concern. The IMF’s October financial-stability report named a sharp drop in AI-related shares a leading risk to global markets, noting that the largest technology companies now make up more than a third of the S&P 500, against roughly an eighth a decade ago. When a few firms account for that much of the index and that much of the spending, a shift in their plans reaches the broader market and the growth data alike.

What the data shows

The market itself is not pricing panic. The S&P 500 closed its latest session at 7,714, down a fraction of a percent, while the Nasdaq Composite, where the AI names weigh most, fell 1.4% to 26,186. The Dow slipped 0.3%. The VIX, Wall Street’s gauge of expected volatility, sat at 16.4, low by historical standards and down on the day. The 10-year Treasury yield held at 4.99%. The split in the tape mirrors the split in the earnings: the broad market steady, the technology-heavy index giving back ground as investors weigh how much spending is too much. Capital-expenditure plans from the three largest spenders run into the hundreds of billions of dollars for this year alone, a sum that now registers in the national growth accounts rather than only in corporate ones.

What would settle it

The next read lands within hours. Amazon reports Thursday afternoon, and its cloud division, Amazon Web Services, together with its own capital-spending figure, will show whether the pattern from Microsoft and Alphabet holds across the group. Beyond that, the companies have already put numbers on the table: Alphabet’s roughly $300 billion capital-spending plan for next year and Microsoft’s calendar-2026 total near $170 billion are commitments investors can track against the revenue meant to justify them. The government’s quarterly growth figures will keep logging how much of the expansion traces to this one category of investment. Each earnings season from here poses the same test the data keeps posing: whether demand is arriving as fast as the capacity being built for it. The numbers are scheduled. The verdict is not.

This is a general-market summary for information only — not investment advice, and not a recommendation regarding any security.