The Most Commonly Quoted Currency Exchange Is That Between the U.s

When the cross rate for currencies offered by two banks differs from the exchange rate offered by a third bank, a triangular arbitrage opportunity exists.

A confusing "quirk" of international exchange rates occurs when calculating the percentage change in spot rates from one period to another. The percent change in the spot rate from one period to another when quoted using foreign currency terms is always greater than the percent changes quoted when using home currency terms.