Margin requirements for stock-index futures hiked

The country's top securities regulator is stepping up its efforts at cracking down on illegal activities involved in the recent stock market turmoil, particularly on stock-index futures trading, officials said on Friday.

China Securities Regulatory Commission has referred 22 cases of suspected market manipulation, insider trading, fabricating and spreading false information to the police, said Zhang Xiaojun, a commission spokesman.

The number of cases now under investigation has risen to 48 so far this year, he said.