Take that, Google. When the search engine mentioned it may shut down its China site, Google.cn, Chinese search engine Baidu's shares jumped 5.6 percent, which is "a huge positive for Baidu," says Citigroup analyst Catherine Leung. Google's Chinese rival already has a 63 percent market share of Internet searches, according to comScore, and if Google closes, Baidu's user base will grow ever larger and add advertisers to their team. Security concerns sparked Google to make the threat, and the company stated Tuesday it will end censorship of China-based searches. Concerns grew when a hacker group called "Iranian Cyber Army" took over Baidu for four hours Tuesday. "If Baidu were able to get the majority of Google's market share that means we are looking at a player with 80 percent to 90 percent market share in China," said Leung.