The US Dollar Index shows the correlation between the US dollar and the currencies of other countries. The most popular dollar index – the USDX – trades on the New York Board of Trade and shows the dollar’s correlation to the following 6 currencies: euro, Japanese yen, Swiss franc, Canadian dollar, Swedish krona and pound sterling. The currencies have different a share of the basket and the calculation of the dollar index is based on this share as averagely-weighted from the cost of the six currencies. The largest share of the basket is taken up by the euro which makes up over 50%. The USDX is used by traders as an indicator of technical analysis. Another widely used index, the FED, is calculated by the Federal reserve system of Philadelphia and is an aggregate dollar rate against 26 different currencies.