Acceptance levels for open source software (OSS) have trumped IDC’s expectations this year, leading the market watcher to hoist its growth forecasts for the market.

The market watcher believes the OSS market will enjoy a 22.4 per cent compound annual growth rate to reach $8.1bn (£4.94bn) by 2013.

That significantly trumps IDC’s best guess last year.

IDC admitted that the level of acceptance among leading businesses since it made its last forecast had been higher than it expected. The economy also accelerated uptake in the closing months of 2008, it added.

A third reason for the revision is that IDC has begun including more projects in its research to generate the forecast.

Michael Fauscette, group vice president of IDC’s Software Business Solutions, said: "OSS is increasingly a part of the enterprise software strategy of leading businesses and is seeing mainstream adoption at a strong pace.”

IDC did, however, suggest there may be limits to the long-term success of the open source model. The hybrid business model is on the increase and would probably end up as the “most prevalent business model”, it advised, not just for open source and closed source vendors, but for on-premise and software-as-a-service (SaaS) vendors.

Fauscette also predicted that niche OSS players would increasingly find themselves the prey of larger vendors.

“As the overall software industry continues to consolidate, it will be key for OSS vendors to reach scale if they plan to continue as a standalone business,” he said.