Amazon Web Services (AWS) maintained its chokehold on the enterprise cloud market in the fourth quarter, but Microsoft and Google's continued growth threatens to break AWS' longstanding dominance, analysts report.

Synergy Research Group (SRG) and Canalys reported total market spending surpassed $50 billion for the fourth quarter, marking an all-time high for cloud spending. That's a 36% year-over-year jump in cloud spending from last year, according to SRG. Those figures were backed up by similar reporting from Canalys, which tracked a 34% year-over-year increase.

AWS' market share stayed constant at 33%, while Microsoft and Google held onto their N0. 2 and No. 3 spots with 21% and 10%, respectively, SRG reported. Meanwhile, Alibaba, IBM/Kyndryl, Salesforce, Tencent, and Oracle followed the major cloud providers, collectively accounting for about 18% of the market. The final tier of providers included China Telecom, China Unicom, Huawei, Fujitsu, NTT, Rackspace, and SAP, with each claiming about 1% market share.

Although the leaderboard hasn't changed much in recent years, SRG chief analyst John Dinsdale wrote "the battle for market share is getting more interesting."

And while Amazon grew faster than the market at large, a fact that helped the provider maintain a significant lead, Microsoft, Google, and Alibaba all grew faster than Amazon, according to Dinsdale

Microsoft has gained almost 9 percentage points since 2017, boosting the cloud provider to a 21% market share, and putting it 11 percentage points behind Amazon.

As the cloud giants’ market shares have grown, they’ve left little room for smaller rivals.

"Google and Alibaba also continue to grow market share, while in aggregate the long tail of small-to-medium sized cloud providers see revenues growing steadily but market shares declining," Dinsdale said. "The rising tide continues to lift all boats, but some are being lifted more swiftly than others."

Cloud infrastructure services have seen a greater diversification of applications, particularly in healthcare and the public sector, Canalys reported. Combined with higher demand for cloud services from ongoing digital transformation and other pandemic forces, these growth patterns aren't all that surprising, the report's authors explained.

Total cloud spending hit $191.7 billion in 2021, a 35% increase from 2020, Canalys reported. Meanwhile, SRG tracked $178 billion in cloud spending, up 37% during the same period.

“It is a strong testimony to the value and attractiveness of cloud services that the 2021 market growth rate actually exceeded 2020 growth, despite the enormous scale that has already been achieved. Enterprises are now spending twice as much on cloud services as they spend on their own data centers,” Dinsdale said.