When the chips are down
The latest Big Mac index suggests the euro is still overvalued
Jul 22nd 2010

ASK Western policymakers how they intend to squeeze growth from their sluggish economies and most pin their hopes on higher exports. That makes exchange rates an especially sensitive topic. A weaker currency improves the competitiveness of a country by making exports cheaper. It also encourages domestic consumers to switch from expensive imports to domestic goods. The Economist’s exchange-rate scorecard, the Big Mac index, shows that currencies continue to be cheap in the developing world but overvalued in Europe.
The index is a lighthearted attempt to gauge how far currencies are from their fair value. It is based on the theory of purchasing-power parity (PPP), which argues that in the long run exchange rates should move to equalise the price of an identical basket of goods between two countries. Our basket consists of a single item, a Big Mac hamburger, produced in nearly 120 countries. The fair-value benchmark is the exchange rate that leaves burgers costing the same in America as elsewhere.
Asia remains the cheapest place to enjoy a burger. China’s recent decision to increase the “flexibility” of the yuan has not made much difference yet. A Big Mac costs $1.95 in China at current exchange rates, against $3.73 in America. Our index suggests that a fair-value rate would be 3.54 yuan to the dollar, compared with the current rate of 6.78. In other words the yuan is undervalued by 48%.
Other Asian currencies such as the Thai baht and the South Korean won are also undervalued. The Brazilian real is one of the few emerging-market currencies that is trading well above its Big Mac benchmark. With interest rates high—the policy rate now stands at 10.75%—Brazil has attracted lots of attention from yield-hungry investors. Burgernomics suggests that the real is overvalued by 31%.
The Big Mac numbers should be taken with a generous pinch of salt. They...