[SHANGHAI] Chinese police slapped a two-year freeze on more than US$670 million of shares owned by the mother of Xu Xiang, the Shanghai hedge fund boss under investigation for alleged insider trading and stock manipulation.

Two companies, one in Beijing and one in Nantong in Jiangsu province, reported the freeze on stakes held by Xu's mother, Zheng Suzhen, in statements to the Shanghai stock exchange on Monday night. Zheng hasn't been named by authorities as being under investigation.

Xu, one of China's highest-profile and top-performing money managers, is among the targets of a Chinese government crackdown that spans executives at brokerage Citic Securities and officials at the China Securities Regulatory Commission after a US$5 trillion summer stock market rout.

The police detained Xu, who's known in China as "hedge fund brother No 1" on the highway between Shanghai and Ningbo on Nov 1, China National Radio reported. Xu, the general manager of Zexi Investment, didn't answer a call to his mobile phone on Tuesday and calls to Zexi's Shanghai and Beijing offices weren't answered.

His mother Zheng's 275 million shares in retailing firm Wenfeng Great World Chain Development Corp. in Nantong were worth 2.16 billion yuan (S$483 million) at Monday's closing price. The company's stock jumped as much as the maximum 10 per cent on Tuesday.

At technology firm Daheng New Epoch Technology in Beijing, Zheng is the biggest shareholder with 129.96 million shares valued at 2.14 billion yuan on Monday. That firm's stock also rose by as much as 10 per cent on Tuesday.

Cheng Min, Wenfeng's securities affairs representative, said the company didn't have any contact information for Zheng. At Daheng, two officials - the board secretary and the securities affairs representative - didn't answer phone calls.

Xu's Zexi managed four of China's top-10 performing hedge funds between June and August, according to Shenzhen Rongzhi Investment Consultant Co. The average return of Zexi's five stock funds has ranked in China's top three each year since the firm was founded five years ago, according to the Economic Daily's website.

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