必须预防美元大跌

　　

　　瑞银(UBS)外汇策略董事总经理曼苏尔•毛希丁(Mansoor Mohi-uddin)

　　

　　英国《金融时》 2009-09-24

　　

　　美元在去年金融危机最严重时期的反弹，是当时决策者眼中为数不多的一丝希望。避险意识的增强促使投资者重新回到安全且流动性强的美国债券，从而避免了美元崩盘。

　　

　　今年，美元汇率再度走软，因愿意冒险的美国投资者买进了收益率较高的外国资产。美元的这种疲软应该是良性的，如果投资者的乐观情绪有所减弱，美元有可能走强。但美元崩盘将给全球经济带来灾难性的后果。加拿大央行(Bank of Canada)和新西兰央行(Reserve Bank of New Zealand)的官员已经对外汇市场的动向提出了警告。本月，20国集团(G20)决策者在匹兹堡会晤时，应该讨论汇率问题。

　　

　　美元暴跌将损害美国经济。外国投资者将为所持美国资产要求更高的回，这将导致债券收益率曲线变得陡峭起来。但美元极度疲弱还会对全球其它国家构成威胁。本世纪初以来的大部分时间里，由于全球经济蓬勃增长，世界经济一直能够适应汇率不断下跌的情况。但在信贷紧缩的环境下，极度疲软的美元，有可能将通缩出口到全世界。

　　

　　在富裕的七国集团(G7)经济体中，官方利率目前处于非常低的水平，各国央行在忙着印钞票，而财政部则面临巨额财政赤字。这使得决策者几乎无力应对本币兑美元汇率的突然上升。在最糟糕的情况下，美元崩盘可能会令一些G7国家陷入流动性陷阱，在这种情况下，即使是极度宽松的货币及财政政策，也无法令其经济摆脱通缩。

　　

　　债务和萧条距离政府诉诸于保护主义仅一步之遥。为了避免踏上这条毁灭性的道路，G7应做好准备，在美元意外暴跌时对外汇市场进行干预。

　　

　　过去30年，G7曾经实施过5次针对主要货币的联合干预行动。1985年，G7签署《广场协议》(Plaza Accord)，以压低美元汇率。1987年，G7在卢浮宫改变立场，承诺为不断下跌的美元提供支持。同样，1995年，G7再次决定出手干预，维护美元。1998年，美国和日本联手卖出美元，以提振日元汇率。2000年，欧洲央行(ECB)说服美联储(Fed)、日本央行(Banks of Japan)、英国央行(Banks of England)和加拿大央行(Banks of Canada)为欧元护盘。

　　

　　在上述5次干预行动中，有4次最终成功地改变了外汇市场的趋势。1985年，美元兑日元及德国马克汇率停止了飙升。1995年，美元汇率开始了一轮持续涨升行情，并延续到整个90年代末期。1998年，“日元套利交易”朝着有利于日元的方向大幅逆转。而本世纪初，欧元汇率很少跌破G7各国央行出手干预、为其提供支持的水平。

　　

　　《卢浮宫协议》(Louvre Accord)是唯一的例外。尽管G7在1987年2月同意为美元提供支持，但由于德国央行(Bundesbank)当年夏季上调利率，美元继续下跌。这造成全球范围内的债券收益率上升，最终导致华尔街1987年10月份的崩盘。

　　

　　因此，决策者应该吸取的教训是，联手干预在外汇市场是行得通的，但它需要与全球利率的变动保持一致。目前这点十分重要，因为美联储打算维持极低的联邦基金利率，直至2010年。联合干预要想获得成功，其他G7成员就需要考虑降息。简言之，欧洲央行需承担调降其再融资利率（目前为1%）的责任，因为日本、加拿大和英国央行已将利率调降至0.50%或更低的水平。

　　

　　对于欧洲央行这样的机构而言，让货币政策屈从于汇率政策，是一件痛苦的事情。但1987年的经历表明，汇率不断暴跌，可能对金融市场和全球经济造成重创。G7应制定一个计划，防止外汇市场重新陷入动荡之中。

G7 needs plan to deal with a plunging US currency　　

　　By Mansoor Mohi-Uddin

　　

　　Published: September 22 2009 03:00 | Last updated: September 22 2009 03:00

　　

　　The rebound of the dollar at the height of last year's financial crisis was one of the few silver linings for policymakers. Increased risk aversion prompted investors to return to the safety of liquid US Treasuries, averting a collapse of America's currency.

　　

　　This year the greenback has weakened again as risk-seeking US investors have bought higher-yielding foreign assets. This dollar weakness should be benign and the currency is likely to strengthen if investor bullishness eases. But a collapse of the dollar would have grave consequences for the world economy. Already officials at the Bank of Canada and the Reserve Bank of New Zealand are warning about developments in the currency markets. This month G20 policymakers should discuss exchange rates when they meet in Pittsburgh.

　　

　　A plunge in the dollar would hurt America's economy. Foreign investors would demand higher returns for holding US assets, causing bond yields to steepen. But extreme dollar weakness also poses a threat to the rest of the world. For most of this decade, the world economy has been able to accommodate sliding currencies as global growth has boomed. But in the credit crunch world, a super-weak dollar risks exporting deflation across the globe.

　　

　　In the rich G7 economies, official interest rates are very low, central banks are printing money and finance ministries are running big fiscal deficits. This leaves policymakers with little scope to deal with a sudden appreciation of their currencies against the dollar. In the worst-case scenario, a rout of the greenback could tip some G7 countries into liquidity traps where extremely loose monetary and fiscal policies are unable to prise their economies out of deflation.

　　

　　It is only a short step from debt and depression to governments resorting to protectionism. To avoid this ruinous path, the G7 should be prepared to act in the currency markets should the dollar plunge unexpectedly.

　　

　　Over the last three decades there have been five bouts of co-ordinated intervention in the major currencies. In 1985 the G7 signed the Plaza Accord to weaken the dollar. In 1987 the G7 changed stance at Louvre and pledged to support the falling greenback. Similarly, in 1995 the G7 again decided to intervene to help America's currency. In 1998 America and Japan sold dollars to prop up the yen. And in 2000 the European Central Bank persuaded the Federal Reserve and the Banks of Japan, England and Canada to support the euro.

　　

　　Four of these five episodes were ultimately successful in changing the trend of the currency markets. In 1985 the dollar stopped overshooting against the yen and the German mark. In 1995 the greenback began a sustained rally that lasted throughout the late 1990s. In 1998 the "yen carry trade" reversed sharply to the benefit of Japan's currency and in the early 2000s the euro rarely traded below the levels where the G7 central banks had intervened to support it.

　　

　　The Louvre Accord is the one exception here. Though the G7 agreed in February 1987 to help the greenback, the dollar continued to slide as Germany's Bundesbank increased interest rates in the summer. This caused bond yields to rise around the world, eventually causing Wall Street to crash in October 1987.

　　

　　The lesson for policymakers therefore is that co-ordinated intervention can work in the currency markets but it needs to be consistent with changes in interest rates globally. This matters now as the Federal Reserve intends to keep the Fed funds rate very low well into 2010. In order for co-ordinated intervention to be successful, the rest of the G7 will thus need to consider cutting interest rates. In short the onus would be on the European Central Bank to lower its refinance rate from 1.00 per cent as the central banks of Japan, Canada and Britain already have interest rates at or below 0.50 per cent.

　　

　　Subordinating monetary policy to exchange rate policy would be painful for institutions like the ECB. But the experience of 1987 shows plunging exchange rates can cause severe shocks to financial markets and the world economy. The G7 should have a plan in case of renewed turmoil in the currency markets.

　　

　　The writer is managing director of foreign exchange strategy at UBS investment bank

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