Amazon Web Services (AWS) remains the cloud infrastructure services leader, controlling about a third (34 percent) of the global market, according to Synergy Research Group.

A Synergy report says all four leading cloud providers — AWS, Microsoft, Google, and IBM — maintained or grew their share of the market in the second quarter of 2017.

Synergy estimates that quarterly cloud infrastructure service revenues have now reached almost $11 billion and continue to grow at over 40 percent per year. This includes infrastructure as a service (IaaS), platform as a service (PaaS) and hosted private cloud services.

AWS last week reported $4.10 billion in revenue for the second quarter, a 42 percent year-over-year growth rate.

“For me the biggest story is that Amazon/AWS is holding on to its market share despite increasingly strong competition from a handful of big and aggressive competitors,” said Synergy analyst John Dinsdale in an email. “Microsoft, Google, and Alibaba are all growing their cloud revenues at impressive rates, but AWS keeps on growing by over 40 percent, per year, despite its huge scale. That is a really difficult feat to pull off.”

Both Microsoft Azure and Google Public Cloud (GCP) nearly doubled their quarterly revenues since the second quarter of 2016. But while Microsoft’s share stands at 11 percent and Google’s at 5 percent, AWS is still over three times the size of its nearest competitor.

Meanwhile, IBM’s market share held steady at 8 percent, driven by its strong showing in hosted private cloud services. While AWS, Microsoft, and Google are the leading providers in IaaS and PaaS, IBM continues to lead in hosted private cloud, Synergy says.

The report also mentions Rackspace as a leading private cloud services provider and says Alibaba has now become the fourth ranked provider in IaaS, thanks to very strong growth in its home Chinese market.

“The continued high overall market growth rates mean that opportunities will continue to exist for niche players that cater to specific needs or communities, but there can be no doubt that the hyperscale cloud providers will continue to grow their market share over the coming quarters and years,” Dinsdale said. “This is a game of scale that requires huge ongoing investments in data center infrastructure, a global presence, and credibility and brand that plays well to some key target audiences.”

To this end, IBM opened eight new data centers globally in the first half of 2017. Google also continues to invest in data centers, opening new GCP regions in Virginia, Singapore, Sydney, and London.