At a stock trading hall for retail investors near People’s Square in Shanghai, the mood is glum.

在上海人民广场附近一个面向散户投资者的证券营业厅，人们情绪低沉。

Shenyin Wanguo, like other Chinese brokerages, maintains its hall for investors to hang around, make a few trades and share tips. Among the mostly elderly investors, zest for market speculation goes hand-in-hand with the socialist conviction that the government can and should protect them from risk.

就像中国其他券商那样，申银万国(Shenyin Wanguo)维持这个营业厅是为了让投资者流连于股市，做几笔买卖，交流炒股点子。在这些以老年人为主的散户中，对市场投机的狂热与社会主义信念同时存在，这种信念就是：政府能够而且应当保护他们免受风险冲击。

“Even I, an old party member, don’t believe the regulators any more,” says Ms Xu, a 76-year-old retiree.

“即使是身为老党员的我，也不再相信监管机构了，”76岁的退休人员徐女士表示。

China’s main stock index lost 5 per cent yesterday, shrugging off an interest-rate cut by the central bank over the weekend. The market has now tumbled 22 per cent since hitting a seven-year high on June 12. Ms Xu blames the securities regulator for approving too many initial public offerings, siphoning demand away from existing shares.

中国主要股指昨日下挫5%，没有被央行在上周末的降息举措打动。自6月12日触及七年高点以来，中国股市已下跌22%。徐女士指责证券监管机构批准了太多的首次公开发行(IPO)，分流了市场对现有股票的需求。

She also lost money punting on internet stocks amid pledges by top leaders to promote the technology sector. ChiNext, the Shenzhen-based start-up index, had more than tripled in the year to June but has since plummeted 30 per cent.

在高层领导人承诺促进科技行业发展的背景下，她投资了网络股，但赔了钱。位于深圳的创业板(ChiNext)在截至6月的一年里上涨两倍多，但自那以来已跌去30%。

“The country is promoting ‘internet plus’ so I bought some internet-themed stocks,” she says. “Their results looked good. But then came a few days of limit-down. Now I’m stuck,” she says, referring to the maximum 10 per cent limit on a stock’s gain or loss on a single day.

“国家在推动‘互联网+'，所以我买了一些互联网主题的股票，”她说。“他们的业绩看起来很不错。但后来连续几天跌停。现在我被套牢了，”她说。跌停指的是股价触及10%的个股单日下跌限度。

Reflecting the surge of retail investors into the market, trading accounts holding at least some stock hit 68m by the end of May, up 27 per cent from a year earlier, according to clearing houses.

散户投资者大举涌入市场的证据之一是，结算所数据显示，至少持有一些股票的交易账户数量在5月底达到6800万，比一年前增加27%。

Yet analysts say the roots of China’s stock boom, and its unfolding bust, lie not in old-fashioned retail trading halls. Instead, margin lending, which did not exist during China’s last big equity boom and bust, has played a central role.

不过，分析师们表示，无论是中国股市的大涨，还是其眼下经历的震荡，根源都不在面向散户的老式营业厅。相反，在中国股市上一轮大涨大跌期间不存在的保证金贷款，这一次起到了核心作用。

Official margin lending through securities brokerages peaked at Rmb2.3tn ($371bn) on June 19, up from just Rmb403bn a year earlier. Goldman Sachs estimates such lending equals 12 per cent of the free-float market capitalisation of margin-eligible stocks, and 3.5 per cent of gross domestic product.

通过券商进行的正规保证金贷款在6月19日达到2.3万亿元人民币（合3710亿美元）的巅峰，而去年此时只有4030亿元人民币。高盛(Goldman Sachs)估计，此类贷款相当于符合融资交易条件的股票的自由流通股总市值的12%，国内生产总值(GDP)的3.5%。

But even that figure fails to capture the full extent of leveraged stock investing. In addition to brokerages, grey-market margin lending through third parties has pumped an additional Rmb500bn to Rmb1tn in borrowed money into the market, according to estimates from Haitong Securities.