For investors trying to figure out which of the big cloud platforms is winning the AI (artificial intelligence) build-out, the most recent batch of earnings reports just delivered an answer that may surprise some.

Alphabet‘s (GOOGL +0.20%) (GOOG +0.27%) latest quarterly results revealed that Google Cloud revenue surged 63% year over year to $20.0 billion. Showing what an incredible feat this is, that growth rate sat well above the 40% Microsoft (MSFT +1.62%) reported for Azure during the same period — and it’s more than twice the 28% growth Amazon (AMZN +1.25%) posted for its own cloud computing business, AWS.

Even more, this was Google Cloud’s third straight quarter of accelerating growth. And looking ahead, a cloud backlog that nearly doubled in just three months suggests this lead could keep widening.

Outpacing the leaders

In terms of sheer size, Google Cloud’s $20 billion still trails AWS’s $37.6 billion and Microsoft’s broader intelligent cloud segment by meaningful margins. Yet growth rates — particularly during a once-in-a-generation infrastructure shift — provide investors with vital insight into which of these companies is best positioned to capitalize on this new era.

That 63% growth rate built on the segment’s recent trend, accelerating from 32% in the second quarter of 2025 to 34% in the third quarter, then 48% in the fourth quarter. Microsoft’s Azure and other cloud services revenue, by contrast, grew 40% in the quarter ended March 31, hovering in the same 39%-to-40% range it has held for three straight quarters. AWS accelerated to 28% — its fastest growth in roughly four years, but still well behind Google Cloud’s pace.

And Alphabet has seen exceptional momentum in its cloud segment’s profitability. Google Cloud’s operating income climbed to $6.6 billion, up from $2.2 billion in the year-ago period. And the segment’s operating margin expanded to 32.9%, up from 17.8% a year earlier.

Notably, Alphabet CEO Sundar Pichai said during the company’s first-quarter earnings call that revenue from products built on Alphabet’s generative AI models grew nearly 800% year over year — a sign that the AI spend is paying off handsomely for Google Cloud customers.

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A backlog that points forward

Perhaps the most striking figure of the quarter, though, wasn’t revenue, but backlog.

Google Cloud’s revenue backlog — the dollar value of committed but not-yet-delivered customer contracts — climbed to over $460 billion, nearly doubling from roughly $240 billion at the end of 2025. And management said it expects to recognize just over half of that backlog as revenue over the next 24 months.

For perspective, this backlog now sits at more than six times annualized first-quarter cloud revenue.

This kind of forward visibility, however, will require massive investment. To this end, Alphabet raised its full-year 2026 capital expenditures guidance to a range of $180 billion to $190 billion, up from a previous forecast for $175 billion to $185 billion. And chief financial officer Anat Ashkenazi indicated that 2027 capital expenditures should “significantly increase” beyond that.

A spending commitment of this magnitude, of course, introduces risk. If AI demand cools or returns on this infrastructure take longer to materialize than management expects, profit margins could come under significant pressure. And competition isn’t standing still either — Microsoft and Amazon are similarly spending hundreds of billions on capital expenditures, with a large portion of that going to AI compute.

Even so, the picture coming out of the first quarter is hard to argue with: Google Cloud is no longer the distant third-place option in cloud computing. It appears to be the fastest-growing platform among the three at exactly the moment when AI workloads are shaping enterprise spending decisions for the next decade.

Sure, trading at a forward price-to-earnings ratio of 32, shares aren’t cheap. But for a business that seems to be gaining ground against two formidable competitors and virtually locking in nearly half a trillion dollars in committed future revenue, that multiple looks reasonable. This latest quarter, in short, arguably only bolsters the bull case for Alphabet stock.