Professional social networking site LinkedIn has secured US$53 million from global private investment firm Bain Capital and other existing investors to expand in Europe, Media Guardian reported Wednesday.

The investment values the company at $1 billion. Other investors include Sequoia Capital, Bessemer Venture Partners and Greylock Partners.

“As the competitive landscape continues to widen and business knowledge-sharing goes global, the importance of being linked closely to both local and international markets becomes critical,” Kevin Eyres, European managing director of LinkedIn, told Media Guardian, calling Europe an “integral part” of the company's growth strategy.

LinkedIn allows people to stay in touch with contacts and colleagues. It has 23 million members around the world, and has growth rates of 108 percent year-on-year.

Jeffrey Glass, venture partner at Bain, told Media Guardian that what separates LinkedIn from other social networks is that “user engagement on LinkedIn actually increases over time, a strong testament to the ongoing value that LinkedIn members derive from the experience.”