as of 01 2026. In the standard the values are called "alphabetic code", "numeric code", "minor unit", and "entity".

According to UN/CEFACT recommendation 9, paragraphs 8-9 ECE/TRADE/203, 1996:
: 8. In applications where monetary resources associated with a currency (i.e. funds) need not be specified and where a field identifier indicating currency is used, the first two (leftmost) characters are sufficient to identify a currency--example: US for United States dollars for general, unspecified purposes where a field identifier