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巨无霸指数以购买力平价这一理念为理论基础，对比全球货币被低估或高估的程度。“汉堡经济学”今年关注的重点是强势的美元和其对全球市场的影响。从商业到经济再到科学技术，《经济学人·商论》精选原刊最具代表性的精彩文章，紧扣全球脉搏。我们不仅关注行业大势，更带来独一无二的分析与洞察，助你在竞争中保持领先。

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《经济学人·商论》2017年一月刊双语试读

肥厚的美元

The all-meaty dollar

巨无霸指数以购买力平价这一理念为理论基础，即长远来看，不同货币的汇率会自动调整，直到相同数量的商品和服务在所有国家中都售价相同。一个巨无霸汉堡在美国售价为5.06美元，但在土耳其只卖10.25里拉（2.75美元），这就意味着里拉的价值被低估。

The Big Mac index is built on the idea of purchasing-power parity, the theory that in the long run currencies will converge until the same amount of money buys the same amount of goods and services in every country. A Big Mac currently costs $5.06 in America but just 10.75 lira ($2.75) in Turkey, implying that the lira is undervalued.

然而，其他的货币对美元的估值还要更低。根据巨无霸指数，墨西哥比索相对美元被低估高达55.9%。上周，因特朗普重提竞选时曾向墨西哥发出的某些威胁，比索也跌至纪录低位。自去年11月以来，比索兑美元已贬值10%。在大国中，以美元计，只有俄罗斯的巨无霸卖得更便宜，尽管过去一年中卢布已经走强。

However, other currencies are even cheaper. In Big Mac terms, the Mexican peso is undervalued by a whacking 55.9% against the greenback. Last week it also plumbed a record low as Mr Trump reiterated some of his campaign threats against Mexico. The peso has lost a tenth of its value against the dollar since November. Of big countries, only Russia offers a cheaper Big Mac, in dollar terms, even though the rouble has strengthened over the past year.

同样受政治不确定因素影响的还有欧元区。荷兰、法国、德国（也许还会有意大利）都预定在今年举行大选。欧元近来已跌至2003年来的最低水平。英国脱欧公投对英磅的冲击还要更大，其兑美元的汇率已跌至1.21，为31年来的最低水平。根据巨无霸指数，欧元与英镑相对于美元分别被低估19.7%和26.3%。

The euro zone is also prey to political uncertainty. Elections are scheduled this year in the Netherlands, France and Germany, and possible in Italy. The euro recently fell to its lowest level since 2003. Britain’s Brexit vote has had an even bigger effect on the pound, which has fallen to $1.21, a 31-year low. According to the Big Mac index, the euro and the pound are undervalued against the dollar by 19.7% and 26.3%, respectively.

巨无霸指数的缺点之一就是它并未计入各国劳动力成本的差异。人们应该并不会因上海的巨无霸要比旧金山的便宜而意外，因为中国工人的薪水要比美国工人低得多。因此，在一个稍微复杂些的巨无霸指数中，我们将一个国家的平均收入考虑在内。

One of the drawbacks of the Big Mac index is that it takes no account of labour costs. It should surprise no one that a Big Mac costs less in Shanghai than it does in San Francisco, since Chinese workers earn far less than their American counterparts. So in a slightly more sophisticated version of the Big Mac index, we take account of a country’s average income.

Historically, this adjustment has tended to raise currencies’ valuations against the dollar, so emerging-market currencies tend to look more reasonably priced. The Chinese yuan, for example, is 44% undervalued against the dollar according to our baseline Big Mac index, but only 7% according to the adjusted one. The deluxe Big Mac index has typically made rich-world currencies look more expensive. Because western Europeans have higher costs of living and lower incomes than Americans, the euro has traded at around a 25% premium against the dollar in income-adjusted burger terms since the euro’s inception.

But what once seemed to be an immutable axiom of burgernomics is true no longer. So strong is the dollar that even the adjusted Big Mac index finds the euro undervalued. The dollar is now trading at a 14-year high in trade-weighted terms. Emerging-world economies may struggle to pay off dollar-denominated debts. American firms may find themselves at a disadvantage against foreign competition. And American tourists will get more burgers for their buck in Europe.