Switzerland and Singapore are among the most expensive places in the world to grab a mug of coffee—overpriced as it already is in the United States. But there's more to the matter than mere inconvenience for tourists. The Wall Street Journal reports on Starbucks becoming an indicator of currency trouble.

The financial community uses dozens of metrics to determine how much a currency should be worth—and which currencies to buy and sell. These often tell starkly different stories. One measure created by the Council on Foreign Relations shows the U.S. dollar is 11% overvalued.

A rival to the Starbucks index is the Big Mac index, as devised by The Economist. Finding it inadequate, the Council on Foreign Relations came up with a Mini Mac index, with the international prices of Apple gadgets as the benchmark: "Minis are a global product that, unlike Big Macs, can move quickly and cheaply around the world."

Photo: Camila Tamara Silva Sepúlveda (cc)