The worldwide public cloud services market grew 27.4% year over year in 2018 with revenues totaling nearly $183 billion, according to results from the 2H 2018 release of the International Data Corporation (IDC) Worldwide Semiannual Public Cloud Services Tracker. This growth rate, which is more than 4.5 times that of the IT industry overall, showed a modest drop from 2017, not unexpected given the growing base of comparison in the public cloud services market, which has more than doubled over the preceding three years.

The top 5 public cloud service providers accounted for 46.3% of all spending growth in 2018 and 35% of all 2018 spending, up 3 points from 2017. This continues a consolidation trend in the overall public cloud services market among the leaders, most pronounced in the combined Infrastructure as a Service (IaaS) and Platform as a Service (PaaS) segments, in which the top 5 vendors accounted for a 63% share of spending.

"Our latest public cloud data continues to show robust growth – headed toward almost $500 billion by 2023 – and consolidating power positions across the board," said Frank Gens, senior vice president and chief analyst at IDC. "The most intense and strategic consolidation – in the combined IaaS and PaaS segments – is being driven by developers' and enterprises' bets on which vendors will sustainably deliver tech innovation for the next decade and beyond."

"Software as a Service (SaaS) continued to be the most highly deployed cloud segment, representing a commanding 62.4% of the total cloud market revenues, including system infrastructure software (SIS). Adoption of cloud enterprise business applications like ERP, SCM, and HCM also accelerated across all segments with most buyers taking a SaaS-first or SaaS-also posture for new applications," said Frank Della Rosa, research director, Software as a Service at IDC.

"The continued demand for applications and the shortage of professional developers fueled the demand for PaaS solutions," said Larry Carvalho, research director, Platform as a Service at IDC. "Cloud native infrastructure grew demand for platform tools to accelerate application development and deployment powered by abstracted container workloads. Although the Asia/Pacific region had just about 11% of total share, the revenue grew faster than the rest of the world."

"The public cloud IaaS market reversed its trend of slowing growth with a robust jump in its year-over-year growth rate," said Deepak Mohan, research director, Cloud Infrastructure Services at IDC. "This shift is notable – given the $24 billion base of this market in 2017 – and was driven heavily by growth among the global market leaders and in the Asia/Pacific (excluding Japan) (APeJ) region, particularly China. Revenue growth for Amazon Web Services and in the APeJ region jointly accounted for 80% of all the spending growth in 2018."