Data from China's two exchanges in Shanghai and Shenzhen showed the combined outstanding balance of margin trading transactions -- the use of borrowed funds on the stock markets -- at 2.03 trillion yuan (USD 328 billion) by the end of trade yesterday.
Under the practice, investors only need to deposit a small proportion of the value of their trade, generating bigger profits for a given amount of money put down -- but also bigger losses.
"Investors are borrowing money without any substantial collateral. They will face enormous risks once the market changes direction," he said.
The China Securities Regulatory Commission (CSRC) cracked down on margin trading in January, causing the Shanghai market to slump 7.70 per cent, its biggest one-day fall since 2008.
But the index resumed its rise. As of Thursday, Shanghai was up more than 40 per cent so far this year, while Shenzhen had surged 91.7 per cent.
The margin trading balance has doubled in just six months. It surged above 1 trillion yuan on December 19 last year for the first time since March 31, 2010, when China's market regulator first allowed the practice.
