Tencent Holdings Ltd., operator of China's most popular instant messaging service—QQ, will pay $300 million in cash for a 10.26-percent stake in Digital Sky Technologies Ltd., a Russian Internet investment firm and Facebook shareholder.

"The investment allows us to benefit from the fast growing Internet market in Russia, as well as to leverage our technical and operational know-how to strengthen the leadership position of Digital Sky," said Martin Lau, President of Tencent.

The Shenzhen-based company said it would develop a long-term strategic partnership with Digital Sky and the companies in which it has invested, as well as "explore further business cooperation with them."

Tencent's QQ controls around 75 percent of China's instant messaging market, compared with Microsoft's 4.5-percent market share for its MSN Instant Messenger service. It also profits from selling virtual items and other online value-added services, as well as its online gaming business.