Why have the prices of bank shares fallen so sharply? A part of the answer is that stock markets have declined. Banks, however, remain the weak link in the chain, fragile themselves and able to generate fragility around them.

银行股价格跌幅为何如此之大？部分答案在于股市的整体下跌。然而，银行仍然是整个经济链条中的薄弱环节，它们本身很脆弱，同时可以把这种脆弱性传导给周围环节。

Between January 4 and February 15 2016, the Standard & Poor 500 index fell 7.5 per cent while the index of bank stocks fell 16.1 per cent. Over the same period, the FTSE Eurofirst 300 fell 9.5 per cent, while the index of bank stocks fell 19.5 per cent.

在2016年1月4日至2月15日期间，标准普尔500指数(Standard & Poor’s 500)下跌7.5%，而其银行股指数下跌16.1%。同一时期，富时Eurofirst 300指数(FTSE Eurofirst 300)下跌9.5%，而其银行股指数下跌19.5%。

The decline of European stocks was a little bigger than that of US ones but the underperformance of the European banking sector was similar. Relative to the overall US market, the index of shares in US banks fell 9.1 per cent, while that of European banks fell 11 per cent relative to European markets — and so only a bit more. (See charts.)

欧洲股市的跌幅稍大于美国股市，但是欧洲银行业的表现同样逊于美国银行业。相对于整个美国股市，美国银行股指数下跌9.1%，而欧洲银行股相对欧洲股市跌幅为11%——所以后者的跌幅只是略大一点。（见图表）

The dire performance of European banks becomes more evident if one takes a longer view. Bank stocks have failed to recover the huge losses they suffered in the wake of the financial crisis of 2007-09. On February 15 2015, the S&P 500 was 23 per cent higher than on July 2 2007 but the US banking sector was still 51 per cent below where it had been then; the FTSE Eurofirst was 21 per cent below its 2007 level, reflecting the botched European recovery, but its banking sector was down by 71 per cent. In the European case a decline of 40 per cent in the value of bank stocks would return them to the 2009 nadir.

如果从更长期看，欧洲银行股的惨淡表现会越发明显。银行股未能从2007-09年金融危机时的巨大跌幅中恢复。2015年2月15日，标普500指数比2007年7月2日高23%，但是美国银行股指数仍比那时低51%；富时Eurofirst指数比2007年时的水平低21%，反映出欧洲糟糕的复苏情况，但是其银行股指数比那时低71%。对欧洲而言，银行股再下跌40%就回到2009年的谷底了。

So what might explain what is going on? The short answer is always: who knows? Mr Market is subject to huge mood swings. Yet a vital consideration, particularly in the US market, is that Robert Shiller’s cyclically adjusted price-earnings ratio is at levels substantially exceeded only in the stock market bubbles that peaked in 1929 and 2000. Investors might simply have realised that the downside risks to stocks outweigh the upside possibilities.

那么怎样解释眼下的情况？简短的回答总是一样的：谁知道呢？市场先生受制于巨大的情绪波动。不过，有一个重要的考虑因素（特别是在美国股市）是，经周期因素调整后的“席勒市盈率”(Robert Shiller’s price-earnings ratio，又称Shiller P/E)，只有在1929年和2000年股市泡沫达到巅峰时，才大幅高于现在的水平。投资者或许只是意识到了银行股的下行风险大于上行的可能性。

Plausible worries could also have triggered such a realisation. Of such worries, there is no lack. One might be anxious about a slowdown in the American economy, partly driven by the strong dollar, weakening corporate profits and a misguided commitment to tightening by the US Federal Reserve. One might fear the short-term damage being done by collapsing commodity prices, which are imposing economic and fiscal stresses on commodity-exporting countries and financial pressures on commodity-producing companies. One might be concerned over the need for sovereign wealth funds to liquidate assets to fund fiscally stressed governments, particularly of the oil exporters. One might worry about a big slowdown in China and the ineffectiveness of its government’s policies. One might fear a new crisis in the eurozone. One might be worried about geopolitical risks, including the threat of war between Russia and Nato, disintegration of the EU and the chance that the next US president will be a hardline populist.

看似合理的担忧也可能引发这样的认识。这类担忧从不缺乏。人们可能会担心美国经济放缓，后者部分由美元走强、企业利润减少以及美联储错误地承诺收紧银根造成。人们可能担心大宗商品价格暴跌——对大宗商品出口国造成经济和财政压力、对大宗商品生产国造成金融压力——带来的短期伤害。人们可能担心主权财富基金不得不变卖资产以向财政吃紧的政府（特别是石油出口国）提供资金。人们可能担心中国经济大幅放缓以及中国政府的政策不起作用。人们可能担心欧元区爆发新危机。人们可能担心地缘政治风险，其中包括俄罗斯和北约(Nato)爆发战争的威胁、欧盟解体以及下一任美国总统将会是强硬的民粹主义者的可能。

More fundamentally, chronic demand deficiency syndrome is worsening, with a slowing China adding to the sickness. It is possible to argue that a financial crisis is unlikely, without prior euphoria. One possible response is that it is the euphoria over China that is over. A better response, however, would be that the high-income economies have not yet recovered from the financial crisis and subsequent eurozone crisis, as ultra-low interest rates show.

更重要的是，慢性需求缺乏综合征正在恶化，中国经济放缓可谓雪上加霜。可以认为不太可能发生金融危机，但之前市场中的欣喜情绪已经消失。一种可能的回答是，对中国的欣喜之情已经结束。然而，更好的答案是高收入经济体尚未从金融危机以及随后的欧元区危机中恢复过来，正如超低利率所表明的那样。

This array of worries, and particularly the ongoing deflationary pressure, throws a sharp light on the plight of the banks. Banks are highly leveraged plays on economies. If economies are sick, banks are likely to be sicker. Worse, the sicker the banks, the sicker will be economies. Worries about banks are shown now not only in the price of their stocks, but also dramatically so in the prices of contingent convertible bonds, or cocos . These bonds are hybrids: debt in good times but convertible into equity when common equity becomes too small relative to banks’ balance sheets. The collapse in the prices of cocos of a number of banks can be seen either as proof that they work or as the possible beginning of a death spiral, in which the signal of stress dries up the funding of fragile banks more broadly (see chart).

这一系列的担忧——特别是眼下的通缩压力——向银行的困境投射了一道强光。银行在经济的基础上有很高的杠杆。如果经济病了，银行可能会病得更重。更糟糕的是，银行病得越重，经济也会病得越重。如今，对银行的担忧不仅表现在它们的股价上，还极大地表现在应急可转债(contingent convertible bonds)的价格上。这些债券都是混合型证券：行情好时是债券，但是当银行的普通权益相对于银行资产负债表过小时，可以转化为权益。许多银行应急可转债的价格崩盘，既可以被视为它们在发挥作用、转化为权益的证据，也可能预示着死亡漩涡的开始，在这样的漩涡里，压力信号在更大范围上使脆弱的银行资金枯竭（见图表）。

Why should banks be so fragile after all the vaunted re-regulation? One answer is that they remain highly leveraged. If one ignores the vanishing trick of risk-weighting, the true leverage of many large banks remains at more than 20 to one. Another answer is that banks are exposed to almost everything. Poor market conditions undermine their returns from broking and wealth management.

在所有被大肆吹嘘的再监管措施落实后，银行为什么还会如此脆弱呢？其中一个答案是，它们仍然高度杠杆化。如果人们忽视风险权重这种消失把戏，很多大型银行真正的杠杆仍然高于20比1。另一个答案是，银行几乎对一切资产都存在敞口。糟糕的市场环境破坏了银行经纪和财富管理业务的收益。

The threat of deflation increases the likelihood of negative interest rates on reserves. The effect of that on the banks is uncertain but also worrying. At least as important is the flattening of the yield curve as returns on longer-term bonds collapse (see chart). A flat yield curve is bad for the profitability of banks, whose business is to borrow short and lend long. Commodity-price falls also raise worries about solvency of borrowers. A bigger issue is the new rules on resolution of banks in difficulty. These threaten creditors with forced conversions into equity. For shareholders, that would mean dilution. For creditors, it might mean unexpected losses.

通缩风险增加了存款准备金实行负利率的可能性。这对银行的影响尚不确定，但是同样令人担忧。至少同样重要的是，随着较长期债券收益率骤降（见图表），收益率曲线趋平。平坦的收益率曲线不利于银行盈利，因为银行的业务是短借长贷。大宗商品价格下滑也引发了市场对借款人偿债能力的担忧。更重要的问题是对困境中银行的处置新规。新规让债权人面临强制转股的威胁。对于股东来说，这将意味着股权稀释。对于债权人来说，这可能意味着意料之外的损失。

The world economy is not necessarily heading for a crisis, it is probably just heading for a slowdown — but risks abound. Moreover, such risks are bound to affect banks, particularly those of bank-dependent Europe. The weakened banks will then damage economies.

全球经济并不一定会陷入危机，它可能只是在走向放缓——但是风险无处不在。此外，这类风险一定会影响银行，特别是欧洲的银行——欧洲经济非常依赖银行。然后，被削弱的银行会损害经济。

Policymakers must remain aware of these downside risks and do what they can to avoid adding to them. One thing remains clear: banks are still the weak links in the global economic chain. People worry about the health of these huge, highly leveraged, extremely complex and opaque behemoths. They are undoubtedly right to do so.

政策制定者必须对这些下行风险保持警惕，尽一切可能避免雪上加霜。有一点仍很明确：银行仍然是全球经济链条中的薄弱环节。人们担心这些高杠杆、极为复杂而且不透明的庞然大物的健康。他们的担忧无疑是正确的。