Explanation : The value of the SDR is the sum of the values of specified amounts of the four currencies that satisfy the following criteria: (i) they are issued by IMF members, or by monetary unions that include IMF members, that have the largest value of exports of goods and services; and (ii) they have been deemed by the IMF to be freely usable currencies. These four currencies currently are the U.S. dolar, the Euro, the Japanese Yen, and the Pound sterling. The SDR value is calculated daily in terms of the U.S. dollar, using the midpoint of the buying and selling spot exchange rates for each currency against the US dollar at noon on the London exchange market as determined by the Bank of England.