In a research note on Thursday, Bracelin cut his price target on Amazon (AMZN) shares to $895 from $905. Granted that’s still a huge number and a slight cut, but Bracelin is seeing what others have noted in the burgeoning cloud computing field: Amazon is no longer the only game in town. Microsoft and Google, in particular, have made a major push to win both startups and big Fortune 500 companies over to their respective clouds.

On Friday, Amazon shares are trading at about $850.96, off slightly from Thursday’s close of $853.42.

It’s interesting, historically speaking, that Pacific Crest is downgrading Amazon based on AWS. Not that long ago, AWS was seen as a side business (and likely a loss leader) for its parent company. Amazon’s primary business has always been seen as retail and e-commerce. Now one could argue that AWS is running the place.

AWS, Microsoft, and Google are big public cloud providers, meaning that they run massive amounts of servers, networking, and storage in data centers worldwide. Business customers can rent those resources instead of building more of their own data centers. AWS was first to this market over ten years ago, but Microsoft (MSFT), Google, IBM, and others have flooded the field in the last few years.

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Microsoft, like Amazon, has invested heavily in data center infrastructure. But unlike AWS, it has a stronger foundation for companies that want to keep running some workloads in-house indefinitely, whereas AWS moves tells customers to move workloads to its cloud, Bracelin told Fortune.

That is accurate, but first Microsoft must deliver its promised Azure Stack product, which is due out mid-year following a delay.

“Amazon has been wildly successful, is by far the market leader, and has a multi-year advantage,”Bracelin explains. “But on the margins for customers who have not embraced AWS, Microsoft offers the option of running Azure inside their own data centers and move workloads in a much less disruptive manner.”

Bracelin also reiterated that as much as we hear about cloud computing, it’s still very early in the game: “Of a total $1.3 trillion IT spend, about $60 billion is in cloud now.”

That leaves a lot of opportunity for AWS, Microsoft, and Google—all of which he—like other analysts including those at market research firm Gartner (IT)—characterize as the Big Three.

IBM, which will host its own big cloud conference next week, is in the game because of its existing relationships with CIOs. But it’s not really in the same discussions as the other three cloud providers, Bracelin argued.

The widely-reported AWS outage earlier this month that took several major websites offline wasn’t a factor in his downgrade, Bracelin said, explaining: “Everyone has outages, even companies with internal data centers.” And, to be fair, Microsoft Azure had a not-so-little blip of its own this week.

Last week, Google (GOOG) hosted a cloud-focused conference in San Francisco, touting new corporate customers such as international banking giant HSBC. But the company still has work to do expanding its data center presence worldwide, which it is doing.

From what he’s seen, Bracelin said Google senior vice president Diane Greene is Google Cloud Platform’s most successful sales person. “But one person can’t do it. They need to build out sales, service support.” Greene, formerly CEO of VMware (VMW), now runs Google’s enterprise efforts, including cloud.

Microsoft is seen as a leader among corporate users because it has relationships with tens of thousands of businesses already using the Windows operating system, Office business software, and SQL Server databases. It’s possible many business customers use or will use Azure to run those Microsoft workloads, Amazon for building and testing new software, and Google for its BigQuery analytics and machine learning capabilities.

In essence, Amazon’s growth will slow mostly because it’s growing from a far bigger base than the rest. AWS, he noted, has about $14.1 billion in annual revenue—compared to $2.5 billion for Azure and approximately $1 billion for Google.

Bracelin concluded in his report: “That said, we do see the pace of AWS share gains and growth moderating in 2017 and 2018.”