The USDX is a composite currency index, averaging the exchange rates between the U.S. dollar and ten major world currencies. A rise in the USDX indicates an increase in the overall value of the U.S. dollar, while a fall in the USDX indicates a weaker dollar.

The USDX's currencies and weights are identical to those of the Federal Reserve Board's trade-weighted dollar index (see left). The USDX is computed by FINEX continuously with exchange rates supplied by over 500 banks around the world.