Margin buying has been soaring in China to record levels for some time now
"But it's not just dumb money that's pouring into stocks. It's dumb borrowed money, too. Margin accounts, which let you take out loans to buy stocks, more than doubled in 2014. And to give you an idea how important this has become to the market, well, just take another look at this chart. Notice how new stock accounts briefly collapsed at the start of the year? That was because the government said it wouldn't let the three biggest brokerages open any new margin accounts for the next three months, so nobody wanted to open any stock accounts at all. As a result, the Shanghai Index fell 7.7 percent in a single day. It more than bounced back, though, once people realized that they could still buy stocks with borrowed money now that China's shadow banks—basically unregulated lenders—had stopped putting money into the faltering property market and started putting it into the flaming-hot stock market instead."
http://www.washingtonpost.com/blogs/wonkblog/wp/2015/03/31/chinas-stock-market-sure-looks-like-a-bubble/
http://www.talkmarkets.com/content/global-markets/china-margin-debt-soars-to-record-1-trillion-yuan-another-central-bank-sponsored-bubble?post=62066