SHANGHAI, July 22 -- No company in Shanghai's Free Trade Zone has been reported for being involved in manipulating futures trade, a municipal government spokesman said Wednesday.

"We have checked with relevant departments and are able to confirm that no company in the Free Trade Zone is suspected of manipulating futures trading in the stock market," said Xu Wei, a spokesman for the Shanghai municipal government, at a press conference.

He refuted recent media reports on a STZ company's involvement in such illegal practices.

"If such practices are found in Shanghai, we are ready to cooperate with investigators closely to handle the cases and maintain a sound market environment for Shanghai's reform and opening up," he said.

Xu said the Shanghai Free Trade Zone has maintained a strict and prudent management and supervision system for investment, trade and finance. "It has taken innovative measures in financial supervision, including precautions against money laundering."

The Ministry of Public Security conducted investigations after clues were found earlier this month that certain trade companies had suspectedly manipulated futures trading in the stock market.

An investigation team led by Vice Minister Meng Qingfeng visited the head office of the China Securities Regulatory Commission on July 9 to investigate what it called "malicious short-selling of stocks and stock indices", an example of the dodgy practices many believed had resulted in the rout in China's stock market.

The team arrived in Shanghai the very next day to search for further clues on such illegal practices.

According to China's criminal law, market manipulators could face up to 10 years in prison and heavy fines.