美元有望迎来一波大牛市行情。美国从“大衰退”(Great Recession)中复苏的情况好于其他发达国家，美元也节节攀升。

　　A wave of upbeat economic figures, the latest being robust February jobs data, have pushed the 10-year benchmark Treasury yield back above 2 per cent and left the S and P 500 stock market index sitting just 1 per cent below a record high. And that is good news for the dollar.

　　一连串经济数据转好（最新表现是2月就业数据强劲），推动美国基准10年期国债收益率回到2%以上，标准普尔500指数也只比历史最高值低1%。这对美元是利好消息。

　　On a trade-weighted basis, the world’s foremost reserve currency has marched 4.5 per cent higher over the past five weeks – gaining with relatively risky assets such as equities as US recovery prospects have brightened – while the euro, sterling and yen have all retreated.

　　随着美国经济复苏前景转好，作为世界主要储备货币的美元与股票等风险资产一同上涨，美元贸易加权汇率过去5周来已累计上升4.5%，与此同时，欧元、英镑和日元全都走低。

　　“It’s becoming increasingly clear that the US is crawling out of the mud faster than other developed economies,” says Nicholas Pifer, portfolio manager at Columbia Management.

　　Columbia Management的投资组合经理尼古拉斯·皮弗(Nicholas Pifer)说：“美国步出困境的速度比其他发达经济体更快，这一点已越来越明显。”

　　This relative US outperformance is restoring the role of interest rates to foreign exchange markets. Put simply, the rise in the dollar is attracting more foreign investors wanting to own US assets that generate additional currency gain. Even as the Federal Reserve has been buying heavily US Treasury bonds under its quantitative easing programme – which should send bond prices higher and yields lower – yields have been rising against those of German Bunds and Japanese government bonds, boosting the dollar. 美国经济相对较好的表现逐渐恢复了利率对外汇市场的作用。简言之，美元走强正吸引更多外国投资者持有美国资产，以获取额外的汇率收益。 恒星Shaun.

　　“The best explanation for this latest leg up in the dollar is growth differentials mediated by interest rate differentials,” says Marc Chandler, global head of currency strategy at Brown Brothers Harriman.

　　即使美联储一直在通过量化宽松计划大量购买美国国债（此举按说会推高美国国债价格、拉低其收益率），美国国债收益率相对德国和日本国债也一直在升高，这对美元具有提振作用。

　　Alan Ruskin, global head of currency strategy at Deutsche Bank, says: “We are getting back to a traditional cycle where the US is at the forefront of a recovery.”

　　布朗兄弟哈里曼银行(Brown Brothers Harriman)全球外汇策略主管马克·钱德勒(Marc Chandler)说：“关于最近美元走强的原因，最好的解释是，这是增长速度差异与利率差异共同作用的结果。”

　　US 10-year yields have risen to their highest premium since August 2011 versus much lower Japanese yields. German two-year yields sit an average of 18 basis points below their US benchmark, the largest divergence since early January, says Mr Chandler.

　　德意志银行(Deutsche Bank)全球外汇策略主管艾伦·拉斯金(Alan Ruskin)说：“我们正回归传统周期，美国重新成为经济复苏的领头羊。”

　　Some warn that this divergence in bond yields may not last. If so, the recent burst of dollar strength could prove temporary. Jose Wynne, head of global FX strategy at Barclays, says investors looking for a firmer signal of sustained dollar strength should wait for it to rally against a broader pool of currencies, including those of emerging nations.

　　美国10年期国债收益率走高，而日本10年期国债收益率则大幅下跌，二者息差已扩大到2011年8月以来的最高值。德国两年期国债收益率平均比美国两年期国债收益率低18个基点，钱德勒表示，目前两者息差处于1月初以来最高水平。

　　There are historical clues to further gains. The last two big periods of dollar ascendancy occurred in the early 1980s and mid-1990s. Those bull runs were marked by a starting point where the dollar was cheaply valued against the backdrop of an improving domestic economy and rising interest rates.

　　有人警告称，债券收益率的这种差异可能不会持久。如果是这样的话，美元最近的强势或只是暂时现象。巴克莱(Barclays)全球外汇策略主管乔斯·温(Jose Wynne)表示，投资者如果希望看到更明确的美元持续走强信号，应该等待美元对更多种货币（包括新兴国家的货币）走高。

　　The dollar index is currently a third below its 2001 peak.

　　从历史情况来看，美元应该会继续上涨。美元上两轮大牛市行情发生在上世纪80年代早期和90年代中期。那两波行情开始时，都正值美国国内经济好转、利率上升，美元正是在这种背景下遭到低估。

　　Much will ride on whether the Fed continues buying bonds, and for how long. Much of the move so far may be anticipation of an end to QE.

　　目前，美元指数比2001年时的峰值低三分之一。

　　“The fact the dollar index is moving higher with risk assets illustrates that the market is pricing in a new phase of the US dollar rallying on strong data, ultimately facilitating a move to higher yields as the Fed becomes more confident that the lags behind in policy have effectively already delivered ‘escape velocity’,” says Richard Gilhooly, strategist at TD Securities.

　　美元后市是否会继续走强，一定程度上将取决于美联储是否会继续购买美国国债，以及购买活动持续多长时间。从迄今情况来看，人们可能预期量化宽松将告一段落。

　　Not all are convinced by such an outcome, however. Tad Rivelle, chief investment officer of fixed income at TCW, says the dollar bounce is likely to fade as QE fails to deliver a sustained US recovery. “The more likely scenario is a stagflationary outcome and I’m not a fan of the dollar longer term.”

　　道明证券(TD Securities)策略师理查德·吉尔胡利(Richard Gilhooly)说：“美元指数随风险资产一同上涨，说明市场现在预期美元进入了凭借强劲数据走强的新阶段，并据此进行操作，进而在美联储更加确信政策滞后效应已有效地使经济产生‘逃逸速度’的情况下，推动美国国债收益率上涨。”

　　Long-term dollar bulls cite another factor: US energy self-sufficiency.

　　然而，并不是所有人都相信这种结果。TCW固定收益业务首席投资官塔德·里韦尔(Tad Revelle)表示，如果量化宽松未能推动美国经济进入持续复苏轨道，那么此次美元反弹可能后继乏力。里韦尔说：“更大的可能性是出现滞涨，我不看好美元的中长期走势。”

　　Just as the Reagan tax cuts and military spending boosted the US economy and dollar in the early 1980s and the dotcom boom and higher productivity fuelled faster growth in the mid-to-late-1990s, some analysts argue the shale gas revolution, by reducing foreign energy imports, will transform America’s manufacturing prospects.

　　看好美元长期走势的人士提到了另一个理由：美国能源现在能够自给自足。

　　“The shale revolution looks like being a positive supply shock for the US dollar,” says Mr Pifer. “From a foreign perspective, dollar assets become more attractive.”

　　一些分析师指出，上世纪80年代早期，里根减税和增加军事开支的举措曾提振美国经济和美元，上世纪90年代中晚期，网络热潮和生产力提高也曾推动美国经济增长率提高，同样，如今的页岩气革命也将通过降低能源进口，令美国制造业的前景焕然一新。 皮弗说：“页岩气革命似乎是一场利好美元的供给冲击(supply shock)。从外国人的角度来看，这提高了美元资产的吸引力。”