美元贬值带来的恐慌

张坤奇

The weather may be cold and wet, but in the rich worlds financial markets it is beginning to feel like August all over again. Credit spreads have widened and shares are pitching from gloom to elation as investors look to the Federal Reserve for solace. The anxiety is unmistakable. But this time the scare is about more than bad mortgage loans and their baleful effect on the credit markets. America may be falling into recession. And a new fear now stalks the markets: that the dollars slide could spin out of control.

A full-blown dollar crisis on top of a credit crunch and a weakening economy would be frightening. It would send financial markets reeling and tie the hands of the Fed, perhaps forcing it to raise interest rates even as recession looms. The sky-high euro would soar further, choking off Europes growth. Political tensions would also rise. Already Airbus has called the dollars decline “life-threatening” and Frances president, Nicolas Sarkozy, has given warning of “economic war”.

At worst, the shadows could darken further. For half a century the dollar has been the hegemonic currency. A large slice of global trade is counted in dollars. Central banks hold most of their foreign-exchange reserves in dollars, a boon for America that has allowed it to issue debt more cheaply. That dominance has survived dollar slides before, as in the late 1970s and mid-1980s. But now, with the euro as an alternative, the fear is of a sudden shift in the global monetary system, with investors switching quickly from one currency to the other.

So far, this remains only a fear. Although the dollar has been falling at quite a lick，it has seen no chaotic slump, but a slide interspersed, as this week, with brief rallies. Americans expectations of future inflation have not yet risen much. Yields on government bonds have fallen: clearly, investors do not yet expect higher premiums for safe American assets. Whether disaster strikes depends on what exactly is driving the dollar down and on how policymakers react.

天气可能变得阴冷而潮湿了，但是富国的金融市场却又一次感受到了8月般的火热。因投资者看好美联储，信贷规模进一步扩展，股市从死气沉沉变得喜气洋洋。然而担忧也是明摆着的。这次恐慌不只是有关不良抵押贷款和它们对信贷市场的不良影响，而是美国可能会进入经济衰退。现在一种新的恐惧正在市场蔓延，那就是美元贬值可能失控。

在信贷紧缩和经济疲软之上爆发一场全面的美元危机将是令人胆颤心惊的。它将使金融市场动荡并束缚美联储的手脚，也许会迫使它在经济衰退迫近时提高利率。欧元将进一步升值，这将制约欧洲的经济增长。政治上的紧张关系也将加剧。空客公司已经把美元贬值称为是“生死攸关”的事。法国总统尼古拉·萨科齐已经发出爆发“经济战”的警告。

最糟糕的是阴影将进一步扩大。半个世纪以来，美元在货币中一直处于霸主地位。全球很大一部分贸易是以美元计价的。各国央行的大部分外汇储备也是美元，这对美国来说是个恩惠，使得它能够以更低的代价来发行债券。这种统治地位在过去曾经使美元摆脱了下滑，如20世纪70年代后期和20世纪80年代中期。 但是，现在有了欧元可供选择，人们担心会出现全球货币体系的突然变动，投资者会从一种货币迅速转向另一种货币。

到目前为止，这还仅仅是一种恐惧。尽管美元已经贬值很多，但还没有出现无序的暴跌，本周在下跌中还有短暂的反弹。美国人对进一步通货膨胀的预期没有发生。政府债券的收益在下降，这清楚地表明投资者还不寄希望从安全的美国财产中得到更高的收益。灾难是否会袭来取决于是什么原因促使美元继续贬值和政策制定者们做出怎样的反应。