Last week’s global sell-off, the worst since January, had all the features that make such market events both frightening and exciting for investors. It serves as a reminder to policy makers of the latent threats to financial stability, and the implication this carries for growth and jobs. It also provides insights for the more bumpy road that lies ahead.
最近一轮全球资产抛售是今年1月以来最为严重的，拥有既让投资者感到恐慌、又让他们感到兴奋的市场事件的所有特征。它让政策制定者感到了金融稳定的潜在威胁，以及这种威胁可能给经济增长和就业带来的影响。它还让人们看到，未来的道路更加崎岖不平。
The sell-off was sharp, sudden and generalised. In just a few days the downturn erased the year-to-date gains for major US equity indices, with virtually every segment – both large and small – experiencing significant losses. To add insult to injury, conventional correlations among asset classes broke down as the spillover of the equity market correction spread beyond corporate credit. Commodities also sold off, as did the safest of all havens, German and US government bonds. Well-diversified asset allocations did little to mitigate portfolio risks.
此次抛售是剧烈、突然和全面的。在短短几天时间里，美国主要股指的下跌就抹平了今年以来的涨幅，几乎所有板块（无论是大还是小）都出现了大幅下挫。雪上加霜的是，随着股市调整的溢出效应蔓延至企业信贷以外，不同资产类别的传统关联也被打破。大宗商品也遭到抛售，最安全的避险资产德国国债和美国国债同样如此。多样化投资无助于减轻投资组合风险。

Rather than being driven by a single factor, the correction reflected the cumulative impact of multiple causes that markets could no longer shrug off given high valuations and unbalanced investor positioning. They covered geopolitical, financial, economic and policy factors.
考虑到市场的高估值和投资者头寸失衡，此次调整反映出市场不再无视多种因素——而非仅仅受到单一因素的推动——累积的影响。这些因素涵盖地缘政治、金融、经济和政策几个方面。
Geopolitical tensions
地缘政治紧张局势
On the geopolitical front, markets could no longer ignore mounting tensions that risk disrupting global growth, trade and energy. These include the escalating violence in Ukraine, along with the widening Moscow-west divide that it fuels; civilian deaths in Gaza, and the risk of future radicalisation; the deteriorating rule of law in Iraq and Libya; and the continuing fragmentation of Syria.
市场不再忽视日益加剧的地缘政治紧张局势，后者可能影响全球增长、贸易和能源。这些紧张局势包括乌克兰日益恶化的暴力冲突，再加上由此引发的莫斯科与西方分歧加剧；加沙平民死亡和未来极端化的风险；伊拉克和利比亚法治日益恶化，以及叙利亚持续分裂。
On the financial front, Argentina’s debt default highlighted the extent to which today’s sovereign debt regimes are sensitive to the disruptive influence of intransigent minority holdout creditors facing entrenched governments.
在金融方面，阿根廷债务违约突显出，在政府根基稳固的情况下，当前主权债务体制对拒不妥协的少数不合作债权人所带来的破坏性影响是多么的敏感。
Meanwhile, economic data out of Europe accentuated concerns about the region’s weak recovery. And, on the policy side, more hawkish statements from a growing number of US Federal Reserve officials raised questions about the central bank’s resolve to continue its steadfast support for markets and the economy.
与此同时，欧洲发布的经济数据加剧了人们对该地区经济复苏疲弱的担忧。从政策方面来说，越来越多的美联储(Fed)官员发表了更具有鹰派色彩的声明，这让人对美联储继续毫不动摇地支持市场和经济的决心产生怀疑。
Having already rallied beyond levels easily validated by underlying fundamentals, markets were no longer able to ignore the compounding risks of such a set of factors. The result was a generalised retreat with virtually no place to shelter other than cash and true cash equivalents; or, at least, no shelters readily accessible to many investors. (Professionals could protect their portfolios using both short positioning and insurance, via credit default swaps, though many loathe the costs and risks these entail.)
市场已经上涨至基本面所能支持的水平以上，它们不再能够忽视这一系列因素累积的风险。结果是除了现金和真正的现金等价物以外，几乎所有资产类别都无法抵御市场的全面下挫。或者最起码来说，许多投资者都无法轻易地避险（专业人士可能利用空头头寸和通过信用违约互换(CDS)保险机制来保护他们的投资组合，尽管许多人厌恶这些工具必然带来的成本和风险）。
The breakdown in traditional correlations among different asset classes renders such a sell-off even more unsettling, potentially triggering investor reactions that compound the initial adverse market moves. Over the years I have found two tools particularly helpful for understanding these reactions.
不同资产类别之间的传统关联被打破，导致此类抛售更令人担忧，有可能让投资者做出加剧最初不利的市场走势的反应。多年来，我发现两个工具尤其有助于理解这些反应。
Behavioural insights
行为金融和柠檬理论
The first comes from behavioural finance, which reminds us that certain characteristics, such as natural herding tendencies and destabilised framing mindsets, encourage subsequent market overshoots. Second, the “Markets for Lemon” hypothesis formulated by George Ackelof in 1970 explains why information asymmetry and signalling problems expose both strong and weak securities to large market sell-offs notwithstanding quite large differences in their fundamentals.
首先是行为金融，它提醒我们，某些特征，比如天生的羊群倾向和破坏稳定的框架思维，鼓励了随后的市场过度反应。其次，乔治•阿克洛夫(George Ackelof)在1970年提出的“柠檬市场”假说解释了为何信息不对称和信息传递问题让证券无论优劣都受到市场大幅抛售的影响，尽管这些证券的基本面存在巨大的差异。
These insights are likely to prove particularly relevant given the extent to which the prior period of volatility repression by central banks has induced investors to leverage positions and, in the process, compress a host of risk premia (including credit, default, equity liquidity and volatility). At the same time there is little appetite among broker-dealers to warehouse risk. Indeed, rather than serving as a shock absorber, their current approach to balance sheet management initially amplifies market overshoots.
鉴于各国央行前期大力抑制波动性，从而诱使投资者举债增加头寸，并在此过程中压缩一系列风险溢价水平（包括信贷、违约、股票流动性和波动性），这些观点可能尤其具有重要意义。与此同时，经纪自营商几乎没有承担风险的想法。实际上，它们当前的资产负债表管理方式最初放大了市场过度反应，而没有对冲击起到缓和的作用。
All this should also worry western policy makers. Because of political problems that preclude a comprehensive policy approach, they have been forced to rely on asset markets as the conduit for attaining their growth and employment objectives. As such, the higher the probability of generalised market sell-offs, the greater the risks to financial stability and the wellbeing of Main Street.
所有这些也应该让西方政策制定者感到担心。由于政治上的问题，他们无法实施全面的政策手段，只能被迫把资产市场作为实现增长和就业目标的通道。就此而言，市场全面抛售的可能性越高，金融稳定性和普通民众福利面临的风险就越大。
Yet technical sell-offs also offer opportunities for those able and willing to underwrite high price volatility. Because they initially hit both strong and weak assets, investors can pick up good assets at overly depressed prices. The hope is that such investors can, and will, act in enough numbers and on a sufficiently timely basis to avert economic damage from generalised market downturns.
然而技术性抛售也为那些有能力、也愿意承担较高的价格波动性的人提供了机遇。因为它们最初对所有资产（无论强弱）都造成冲击，投资者可以以极为便宜的价格购得好的资产。希望在于，能够而且将会采取行动的此类投资者足够多，而且也足够及时，能够避免市场全面下跌对经济造成破坏。