At a stock trading hall for retail¹ investors² near People’s Square in Shanghai, the mood is glum³.

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, zest⁴ for market speculation⁵ goes hand-in-hand with the socialist⁶ 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。

“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 sector⁷. ChiNext, the Shenzhen-based start-up index, had more than tripled in the year to June but has since plummeted⁸ 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 analysts¹⁰ say the roots of China’s stock boom, and its unfolding bust¹¹, lie not in old-fashioned retail trading halls. Instead, margin¹² lending, which did not exist during China’s last big equity¹³ 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 leveraged¹⁵ 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.

但是，就连上述数字也未能充分反映杠杆炒股的规模。除了券商外，据海通证券(Haitong Securities)测算，通过第三方进行的灰色市场保证金贷款，也向股市输送了5000亿至1万亿元人民币。

Brokerages limit margin leverage¹⁴ to a ratio of two to one and require clients to put up at least Rmb500,000. By contrast, Xunqianwang, a company that connects punters with borrowed money, allows leverage of up to six to one, and requires as little as Rmb2,000 of the client’s own funds. The company, whose Chinese name translates as “search for money”, boasts that new clients can gain approval in an hour.

券商对保证金贷款规定的杠杆率上限为2比1，并要求客户至少拿出50万元人民币本金。相比之下，在炒股者与资金之间牵线搭桥的寻钱网允许最大为六比一的杠杆率，而且只要求客户自己至少拿出2000元人民币。寻钱网夸口说，新客户有望在一小时内获得批准。

“We can still control the risk because we strictly¹⁶ examine and assess every client,” says Zhong Jingtian, the founder¹⁷ and chief executive. The company restricts which stocks a client can buy and does not give loans to a single client exceeding Rmb3m.

“我们仍然可以控制风险，因为我们严格审查和评估每一个客户，”寻钱网创始人和首席执行官周竞天表示。该公司对客户可以买入哪些股票实行限制，而且不向单一客户提供超过300万元人民币的贷款。

Analysts say the proliferation of margin lending creates the risk of a snowball effect as margin investors, faced with mounting losses, are forced to liquidate¹⁸ their positions unless they can post additional collateral¹⁹.

分析师们表示，保证金贷款的泛滥带来了雪球效应风险，因为在亏损越来越大的情况下，利用保证金的投资者除非能够拿出额外担保金，否则将被迫平仓。

David Cui, equity analyst⁹ at Bank of America Merrill Lynch, estimates that the Shanghai Composite would need to fall an additional 40 per cent for large-scale margin calls to kick in on official margin lending. “However, this doesn’t mean that margin call is not a serious risk right now,” he wrote in a note yesterday. “The selling pressure so far has mainly come from stock-related borrowings via various unofficial channels where the leverage is much higher.”

美银美林(BofAML)股票策略师崔伟(David Cui)估计，上证综指(Shanghai Composite)还需要再下跌40%，才会触发正规保证金贷款的大规模追加要求。“不过，这并不意味着追加保证金通知现在不是一个严重风险，”他在昨日一份简报中写道。“迄今的抛压主要来自各种非正规渠道的股票相关借款，它们的杠杆率要高得多。”

Some analysts still expect the market to rebound²⁰. They argue that the fundamental factors underpinning²¹ the rally, especially loose monetary²² policy and ongoing²³ economic reforms in China, are still intact, even as valuations now look more reasonable.

一些分析师仍预计市场将反弹。他们认为，支撑股市涨势的一些基本面因素，尤其是中国的宽松货币政策和正在开展的经济改革，仍然完好存在，同时现在的估值看起来较为合理。