Shares of alibaba.com, the country's biggest corporate e-commerce site, jumped the most in around four years Wednesday after its parent company announced a bid to buy out minority shareholders.

Alibaba Group announced late Tuesday that it will offer HK$13.50 ($1.74) a share for 27 percent of the shares it does not own in Alibaba.com, a B2B e-commerce website. The transaction will amount to HK$19.6 billion.

The Hong Kong-listed B2B site's shares surged 42.7 percent to close at HK$13.2 per share Wednesday.

"Taking the unit private will help us avoid the pressures of managing a listed company and will bring returns to investors," Alibaba's CEO Jack Ma Yun said.

Ma has been negotiating with Yahoo! Inc to buy the 40 percent stake that the US company owns in Alibaba Group. But the talks have not yet yielded a desirable outcome due to a conflict of interests.

But full control of Alibaba.com may be a new step for the group to reach an agreement with Yahoo!, Li Weidong, a capital market research director at China Venture, told the Global Times Wednesday.

"The privatization of alibaba.com could help Yahoo! gain both cash and asset income, while Ma will get more flexibility in dealing with the assets, which can pave the way for buying back the 40 percent stake held by the US company," Li noted.

But according to the group's announcement, the planned buyout of alibaba.com is unrelated to negotiations between Alibaba Group and Yahoo!.

"The privatization of the site can allow Ma to improve its management efficiency and develop a long-term strategy," Liu Guanwu, an analyst at Analysys International, told the Global Times yesterday.

After the delisting, the company will not need to make quarterly information disclosures, which have caused problems in the past due to profit fluctuations, noted Liu.

"Ma can focus on the long-term growth of the company without having to worry about investor sentiment," Liu said.

Li Daxiao, director of the research institute of Yingda Securities Co, said that it was a good buyout opportunity, because "the market value of the stock is not very high, which means the buyout cost will be low."

Su Huiyan, an analyst at consultancy iResearch, said that Alibaba may reorganize its assets, including alibaba.com, to launch a group IPO later, since "Ma has been thinking about an e-commerce group which combines B2B, B2C, C2C and online payments businesses together."

But Li of China Venture said it was unlikely. "The parent company's affiliated firms, including taobao.com and tmall.com, might list separately so as to gain higher combined market value."