Amazon retained its dominance at the top of the infrastructure-as-a-service (IaaS) market with steady growth in 2018, while competitors Microsoft, Alibaba, Google, and IBM made major gains, according to a report from Gartner.

The worldwide IaaS market grew 31.3% in 2018 reaching $32.4 billion in total revenues, the report said. Of that, the top-five providers accounted for nearly 77% of the global IaaS market share.

“Despite strong growth across the board, the cloud market’s consolidation favors the large and dominant providers, with smaller and niche providers losing share,” said Sid Nag, research vice president at Gartner in a statement. “This is an indication that scalability matters when it comes to the public cloud IaaS business. Only those providers who invest capital expenditure in building out data centers at scale across multiple regions will succeed and continue to capture market share. Offering rich feature functionality across the cloud technology stack will be the ticket to success, as well.”

Leading the pack was Amazon — the largest and most profitable IaaS provider — which claimed nearly half of all IaaS revenues in 2018.

Gartner anticipates Amazon, with an estimated $15.5 billion in IaaS public cloud sales in 2018, will continue to dominate the market as it “aggressively” expands into new markets and services.

In the No. 2 spot, trailing Amazon by a wide margin, Microsoft reported strong growth in 2018 with revenues topping $5 billion up 60.9% from the year before.

Coming in third was China-based vendor Alibaba Cloud, which experienced the strongest growth with revenues up 92.6% in 2018. According to Gartner, Alibaba’s success was largely driven by aggressive investment in research and development compared to other providers.

Google, which captured the No. 4 position with $1.3 billion in revenues according to Gartner’s report, also saw strong growth in 2018 with revenues up 60.2% from the prior year.

“Google’s cloud offering is something to keep an eye on with its new leadership focus on customers and shift toward becoming a more enterprise-geared offering,” Nag said.

In a distant fifth place was IBM with $577 million in IaaS revenues reported in 2018. The company also saw the weakest growth of the top five providers at 24.7%. However, according to the Gartner report, IBM still managed to outpace smaller providers, which collectively grew at a pace of 11%.

According to Nag, these companies' continued growth will likely drive market consolidation through 2019.

“Consolidation will occur as organizations and developers look for standardized, broadly supported platforms for developing and hosting cloud applications,” he said.