Something peculiar is happening in western capital markets. Almost every measure of volatility has tumbled to unusually low levels. If you look at the degree of actual (or “realised”) price swings – and projected (or “implied”) future movements – investors are behaving as if the world is utterly boring.

西方资本市场正在发生一件怪事。几乎所有波动率指标都跌至异常低的水平。看看实际价格波动程度（即“实际”波动率）和预期的未来价格波动程度（即“隐含”波动率）吧：从投资者的表现来看，世界实在是太无趣了。

This is bizarre. Financial history suggests that at this point in an economic cycle, volatility normally jumps; when interest rate and growth expectations rise, asset prices typically swing (not least because traders start betting on the next cyclical downturn). And aside from economics, there are plenty of geopolitical issues right now that should make investors jumpy. European elections have just propelled populist leaders into power, and events in Ukraine and the Middle East are tense.

这很奇怪。金融史告诉我们，当经济周期达到这一节点时，波动率通常会飙升；当利率和增长预期上升时，资产价格往往大幅波动（重要原因是交易者开始押注下一场周期性衰退）。而且，除了经济规律之外，当下还有一大堆令投资者神经紧张的地缘政治问题。欧洲的选举刚刚将民粹主义领导人推上权力舞台，乌克兰和中东则局势紧张。

But investors are acting as if they were living in a calm and predictable universe. Take a look, for example, at Wall Street’s so-called “fear index”, the Vix, which measures the implied volatility of S&P 500 equities. During the financial crisis this surged above 80, and later hovered around 30; it is now just above 11, a low level not sustained since 2007.

但投资者却好像生活在平静、可以预料的世界里。例如，看一下华尔街所谓的“恐慌指数”Vix，它衡量的是标普500 (S&P 500)指数期权的隐含波动率。金融危机期间，Vix指数飙升到80以上，后来在30左右徘徊；如今它仅略高于11，2007年以来还未有过如此低位。

Similarly, the “implied equity vol-of-vol” index (a derivative of volatility measures) is at its lowest level since 2006, and implied volatility in the euro-dollar currency markets is at its lowest since 2007. Bond price swings are very low too, and realised and implied price volatility for oil prices is also at a decade low.

类似地，“隐含股票波动率的波动率”(implied equity vol-of-vol)指数（波动率指标的衍生品）处于2006年以来的最低水平，欧元兑美元汇率市场的隐含波动率处于2007年以来的最低水平。债券价格波动同样很低，油价的实际和隐含波动率也处于十年低位。

“There is no demand for protection [against turbulence],” observes Mandy Xu, an equity derivatives strategist at Credit Suisse. “[Investors in] the options markets are not pricing in any big macro risks. This is very unusual.”

“市场上没有什么防范（动荡）的需求，”瑞信(Credit Suisse)股票衍生品战略师Mandy Xu表示，“期权市场（投资者）没有将任何大的宏观风险纳入考虑。这是很不寻常的。”

Why? If you want to be optimistic, one possible explanation is that the economic outlook has indeed turned benign. For while western economic growth rates have been disappointingly slow since 2008, the good news is that recovery is now afoot, at a fairly steady pace, and the disaster scenarios that used to spook investors – such as an imminent break-up of the eurozone or the debt debacle in Washington – have not materialised; or not yet. More important still, after several years of wild monetary experiments, investors are more willing to accept that western central bankers will do “whatever it takes” to support the markets; they thus expect rates to remain stable and low for a long time – even if some central banks, such as the US Federal Reserve, reduce their level of stimulus.

为什么会这样？如果你是乐观主义者，一个可能的解释是：经济前景确实已经转好。原因是，虽然西方经济增速自2008年以来一直低得令人失望，但好消息是复苏正在稳步进行，而且曾经引起投资者恐慌的灾难情形——例如欧元区即将解体或美国债务危机——并没有成真，或者说尚未成真。更重要的是，在多年大胆的货币政策试验后，投资者现在变得更愿意接受西方央行管理者会“不惜一切代价”支撑市场的观点；因此，他们预期利率将长期稳定在低位——尽管美联储(Fed)等央行减小了刺激力度。

But there is a second, less-benign possible reason for low volatility: markets have been so distorted by heavy government interference since 2008 that investors are frozen. One issue that may account for the pattern, for example, is that tougher regulations have prompted banks to stop trading some assets. Another is that ultra-low interest rates have made investors reluctant to deploy their cash in public, liquid markets.

但波动率低还有一个不那么美好的可能原因：2008年以来，政府的大规模干预严重扭曲了市场，以至于投资者被“冻结”了。更严格的监管法规导致银行不再交易某些资产，这或许能解释这种现象。另一个解释是，超低利率使得投资者不愿把资金部署在流动性强的公开市场。

And there could be a more subtle issue at work too: investors are so unsure what to make of this level of government interference that they are unwilling to take any big bets. Far from being a sign of sunny confidence in the future, ultra-low volatility may show that investors have lost faith that markets work.

或许还有一个更微妙的因素在发挥作用：投资者非常不确定该如何看待这等规模的政府干预，因此不愿意下大赌注。超低波动率远不能代表对未来充满信心，它可能表明投资者已对市场的运转失去信任。

In reality, nobody knows which of these explanations holds true; I suspect that government meddling and low interest rates are the key factors, but academic research on this issue is thin. However, one thing that is clear is that the longer this pattern remains in place, the more wary investors and policy makers should be.

事实上，没人知道上述哪种解释是正确的；我猜测政府干预和低利率是关键因素，但这方面的学术研究不多。不过，有一点很明确：这种局面维持得越久，投资者和政策制定者就越应当警惕。

For while ultra-low volatility might sound like good news in some respects (say, if you are a company trying to plan for the future), there is a stumbling block: as the economist Hyman Minksy observed, when conditions are too calm for too long, investors assume too much leverage, creating asset-price bubbles that eventually burst. Market tranquillity tends to sow the seeds of its own demise and the longer the period of calm, the worse the eventual whiplash.

这是因为，虽然从某些角度看，超低波动率听上去可能像是好消息（例如，对一家试图规划未来的公司来说），但存在一个问题：正如经济学家海曼•明斯基(Hyman Minsky)观察到的那样，如果极端平静的市况维持得太久，投资者就会主动背负太高的杠杆，催生出终将破裂的资产价格泡沫。市场平静往往为它自身的崩盘播下种子，平静持续得越久，最终的伤害就越严重。

That pattern played out back in 2007. There are good reasons to suspect it will recur, if this pattern continues, particularly given the scale of bubbles now emerging in some asset classes. Unless you believe that those governments will be able to bend the markets to their will indefinitely. And that would be a dangerous bet indeed.

这种局面曾在2007年上演。如果现在的局面持续下去，我们有充分理由认为一切将会重演，特别是考虑到某些资产类别正在涌现大量泡沫。除非你相信政府能无限地让市场屈从于自己的意志。这种想法其实也是一个危险的押注。