Special drawing rights (SDRs) are an international reserve asset, created by the IMF in 1969 to supplement its member countries' official reserves. Its value is based on a basket of four key international currencies, and SDRs can be exchanged for freely usable currencies. In short, SDRs are supplementary foreign exchange reserve assets defined and maintained by the International Monetary Fund (IMF). Not a currency, SDRs instead represent a claim to currency held by IMF member countries for which they may be exchanged. As they can only be exchanged for Euros, Japanese yen, UK pounds, or US dollars, SDRs may actually represent a potential claim on IMF member countries' non gold foreign exchange reserve assets, which are usually held in those currencies. While they may appear to have a far more important part to play, or, perhaps, an important future role, being the unit of account for the IMF has long been the main function of the SDR.
Created in 1969 to supplement a shortfall of preferred foreign exchange reserve assets, namely gold and the US dollar, the SDR's value is defined by a weighted currency basket of four major currencies: the Euro, the US dollar, the British pound, and the Japanese yen.
SDRs are denoted with the ISO 4217 currency code XDR. SDRs are allocated to countries by the IMF. Private parties do not hold or use them. As of March 2011, the amount of SDRs in existence is around XDR 238.3 billion, but this figure is expected to rise to XDR 476.8 by 2013.