Special drawing rights are supplementary foreign exchange reserve assets defined and maintained by the IMF to supplement the official reserves of its member countries. It is a potential claim on the freely usable currencies of IMF members, thereby increasing liquidity of a country.
The basket of currencies that define the SDR include the US dollar, Euro, Chinese Yuan, Japanese Yen, and the British Pound."" Inclusion of a currency requires that it is freely exchangeable, i.e. there is no government restrictions on currency exchange