Parallels Inc, which makes Parallels Desktop for Mac software, acknowledged on Monday that it is owned by SWSoft after a report in Fortune magazine broke news of the relationship between the companies.

Parallels Desktop for Mac software has won kudos from critics and users, but the general perception of the company was that it was a start-up success story. SWsoft's ownership of the company changes that view.

SWSoft, a company that focuses on server-side virtualisation, "quietly" purchased Parallels three years ago, said Benjamin Rudolph, a Parallels spokesman. However, Parallels has operated as an independent company since then and will continue to do so, he said.

A joint press statement by Serguei Belousso, CEO of SWsoft, and Nick Dobrovolskiy, CEO of Parallels, also acknowledged SWsoft's purchase of Parallels, but said the companies will continue to focus on different segments of the virtualisation market.

"About virtualisation specifically, management of both companies has always believed that these different types of virtualisation each has its own advantages," the CEOs said in the statement. "And both types can work side by side for maximum benefit."

SWsoft is backed by investment from well-known venture capital firms Intel Capital, Insight Venture Partners and Bessemer Venture Partners.