汉堡经济学

汉堡经济学

Burgernomics

Watch your BMI

Investors are gorging themselves on American assets

汉堡经济学
关注你的巨无霸指数(BMI)
投资者开始疯狂囤积美国资产

ECONOMISTS think prices, like spilt ketchup, are sticky. They move only slowly as firms digest economic conditions. Financial markets are an exception. Computerised trading by thousands of participants means prices, especially of currencies, can move in a McFlurry.

经济学家认为，价格就像撕开的蕃茄酱一样，总是粘糊糊的，它们只有在公司消化吸收了经济环境因素以后才会缓慢变化。而金融市场则是一个例外，数以万计的量化交易有，意味着价格，特别是货币的价格，可能会像麦旋风冰淇淋中一样急速波动。

Since The Economist last updated the Big Mac index (BMI), our lighthearted guide to currency valuation, burger prices have remained constant in 19 of 44 countries. But every currency has shifted in value (see chart 1).

自从经济学人上一次更新巨无霸指数，也就是，我们对货币价值的简化指标，汉堡的价格在44个国家中的19个国家保持稳定。然而，每种货币的价值已经发生了变动。

Our index uses a nugget of economic wisdom called purchasing-power parity: currencies should adjust until goods cost the same everywhere. If, once converted into dollars, Big Mac prices vary, one or other currency looks dear. Big movements in exchange rates, without similarly supersized shifts in burger prices, can send a currency up or down the index.

我们的指数使用了一种珍贵的经济学智慧，被称为购买力平价的概念：调整货币的价值直到物品的成本在各个地区能保持一致性。比如，如果转换成以美元计价，巨无霸的价格发生了变化，那么其中的一种货币会更吸引人。货币汇率的巨大变化，如果没有带来汉堡价格同样巨大的变化，那么可能会造成货币指数上升或者下降。

That explains why the Argentine peso has been the biggest mover since January. Then, it looked 25% undervalued compared with the dollar; today, that has swelled to 51%. The peso tumbled on fears of a debt crisis and inflation.

这解释了为什么阿根廷比索从一月份以来，成为变动最大的货币。也就是说，比索相对于美元贬值了25％；而今天，这一贬值幅度已经扩大到了51％。比索的币值下滑，源于对债务危机和通货膨胀的担忧。

For similar reasons, two other emerging-market currencies, the Turkish lira and Brazilian real, are also big movers. Only the valuation of Norway’s krone has moved much on account of purchasing power. A 14% fall in the dollar price of a Norwegian Big Mac has taken the krone from looking 18% overvalued in January to 5% undervalued now.

基于同样的原因，另外两种新兴市场的货币，土耳其里拉和巴西雷亚尔，也是变化较大的货币。只有挪威克朗的价值是缘于购买力变化。以美元计价的挪威巨无霸价格下降了14％，使得挪威克郎从一月份升值18％转为现如今贬值5％。

This shift should be taken with a pinch of salt, however; burgers may be getting cheaper, but overall Norwegian inflation is a bland 2.6%.

然而这种变化应该是缘于一小撮盐；汉堡的价格可能变得便宜了，但总体上，挪威的通货膨胀率只是平淡无奇的2.6%。

Sometimes, currency traders foresee long-term changes that have yet to move domestic prices. That may be true in Britain, where the pound has been particularly cheap since the Brexit vote in 2016 (see chart 2).

有时候，货币交易员会预测可能会影响本地价格的长期变化趋势。在英国，的确如此，自从英国2016年脱欧后，英镑变得特别便宜。

It now looks 23% undervalued. At other times, currencies deviate from fundamentals because of temporary disparities in risks and short-term interest rates. America’s economy is sizzling and the Federal Reserve is raising rates, but growth has flattened off elsewhere.

现在看起来，英镑已经贬值了23％。在其它的时候，由于暂时与风险和短期利率的不一致，导致货币偏离其基础价值。美国经济正欣欣向荣，美联储正走在加息的路上，但是其它地区的增长则表现平平。

That has made the dollar as strong as a bull. Almost every currency in the index has weakened relative to the greenback since January. Only two, the Swiss franc and the Swedish krona, now look overvalued against it.

这一切使得美元气壮如牛。从一月份以来，指数中差不多每种货币，相对于绿色的美元都显得疲弱。目前看来，只有两种货币，包括瑞士法朗和瑞典克朗，相对美元升值。

One beef with the BMI is that burgers cannot easily be traded across borders. Neither can some inputs to production, such as land and labour. To take account of this, we also produce another version of the index.

巨无霸指数中最重要的一点是，汉堡包不容易进行跨境交易，还有一些生产中的要素投入比如土地和劳动力，同样如此。考虑到这些因素，我们也在思考构建另一种形式的指数。