Key bourses double margin requirements

New rules to help curb leverage, prevent market volatility, says securities regulator

The Shanghai and Shenzhen stock exchanges raised deposit requirements for margin trading to 100 percent from the current 50 percent on Friday, as part of China's efforts to curb market volatility.

Margin trading refers to stock purchases made using borrowed money and was cited as one of the main culprits for the market rout earlier this year.