ISO 4217 [1] specifies that the first two letters in the currency code correspond to a ISO 3166-1 alpha-2 country code so using "BTC" would clash with Bhutan. C

ISO 4217 [1] specifies that the first two letters in the currency code correspond to a ISO 3166-1 alpha-2 country code so using "BTC" would clash with Bhutan. Currency codes that aren't associated with countries typically start with an "X". For example, "XAU" is a troy ounce of gold, and "XBA" is for European Composite Unit. Unfortunately, "XBC" is used for European Unit of Account 9, but they could do something like "XBT" or "XCN" for BitCoin. [1] http://en.wikipedia.org/wiki/ISO_4217 http://en.wikipedia.org/wiki/ISO_4217