The US dollar index, also known as DXY, is a weighted index of the value of the US dollar relative to a basket of foreign currencies. The index was created in 1973 by the Intercontinental Exchange (ICE) to provide a measure of the dollar's strength or weakness in the foreign exchange market.

The basket of currencies included in the US dollar index consists of the euro, Japanese yen, British pound, Canadian dollar, Swedish krona, and Swiss franc. The index is weighted based on the trade volume of each currency against the US dollar.

A higher value of the US dollar index indicates a stronger US dollar, while a lower value indicates a weaker US dollar. The index is widely used by investors, traders, and policymakers as a gauge of the overall strength of the US dollar and as a benchmark for measuring the performance of investments denominated in US dollars.