Alibaba Group, the company that runs China's largest business-to-business website, will make a strategic investment in Sina Weibo, the Chinese version of Twitter, by buying a 15-20 percent stake in the latter, Zhou Jinzeng, a former Alibaba staff member currently in charge of Tencent social media advertisement, said on his NetEase Weibo Saturday.   

Sina Weibo's market value is estimated at between $2 billion and $3 billion, Zhou said in his microblog post.  

Some speculate that the management at Sina Weibo holds 6 percent of the company's shares, 4 percent of shares are options and 10 percent are held by employees, Zhou said, citing unnamed sources.

Other speculations said the management and employees hold a total of 15 percent of shares while the majority of the shares are held by the key management, Zhou said.