China's online advertising market soared 56.2 percent year-on-year to be worth 14 billion yuan ($2.2 billion) in the first quarter of 2012, a major tech and internet information provider said Wednesday.

The market, however, shrank 5.6 percent from the fourth quarter of last year due to seasonal factors, said Dong Xu, of Analysys International.

Dong added that the online ad market this year will be more driven by big sports events like the London Olympic Games and the European Football Championship.

Baidu, the country's largest search engine, had the largest market share of 30.9 percent, followed by Alibaba's 17.9 percent and Google's 6.5 percent, Analysys International said in a research report.

The four web portals, Sohu, Sina, Tencent and Netease, had a 12-percent market share. Sofun, China's largest realty website, had a 2.3-percent share.

(Xinhua News Agency April 25, 2012)