US Dollar (USD)

The US dollar is the world's main reserve currency and the most traded currency on the foreign exchange market by a wide margin. The Bank for International Settlements' surveys have consistently found it on one side of the large majority of all currency trades, which is why so many exchange rates are quoted against it, and why converting between two non-dollar currencies often routes through the dollar behind the scenes.

Several countries use the dollar as their own official currency (a practice called dollarization), including Ecuador, El Salvador, and Panama, and many more peg their currency to it at a fixed rate. Commodities like oil and gold are priced in dollars internationally, so moves in the dollar ripple into prices around the world.