The cloud services market will surpass US$109bn worldwide with business process services (BPaaS) representing the largest segment as infrastructure as a service (IaaS) looks to become the fastest-growing area of the industry.

According to technology researchers Gartner, the public cloud services market is forecast to grow 19.6% this year with BPaaS accounting for 77% while IaaS grows at a rate of 45.4%.

The company says BPaaS is the largest segment primarily because of the inclusion of cloud advertising as a subsegment, reaching $84.2bn from $72bnn last year.

During 2011 cloud advertising represented roughly 47% of the total public cloud services market according to Gartner, making it the biggest identifiable subsegment in the forecast.

"The cloud services market is clearly a high-growth sector within the overall IT marketplace," says Ed Anderson, research director at Gartner.

"The key to taking advantage of this growth will be understanding the nuances of the opportunity within service segments and geographic regions, and then prioritizing investments in line with the opportunities."

Software as a service (SaaS) is the next-largest segment and is expected to hit $14.4bn this year while IaaS is forecast to reach $6.2bn.

Gartner says in 2010 the IaaS market was less than one-third the size of the SaaS market but by 2016 believes it will grow to almost equal.

"The total public cloud services market size in 2011 was $91.4bn, and it will grow to $206.6bn in 2016," Anderson says.

"As the market grows, IaaS will become a larger part of the overall market, while the market share of cloud management and security services will grow as well.

"When targeting specific markets within the cloud services marketplace, we recommend evaluating both potential market size and growth rates.

"These will vary by segment, subsegment, region and country."