Currency is understood to mean paper money (including banknotes) and metallic money, the circulation of which is legally authorized. A person who commits any of the following acts is engaged in counterfeiting currency: fraudulent making or altering of currency, whatever means are employed; fraudulent uttering of counterfeit currency; introduction into a country of, or the receiving or obtaining of counterfeit currency with a view to uttering the same and with knowledge that it is counterfeit; attempts to commit, and any intentional participation in, the foregoing acts; and the fraudulent making, receiving, or obtaining of instruments or other articles peculiarly adapted for the counterfeiting or altering of currency.
Neglecting national variations in the basis of statistical estimates, figures from Interpol indicate that in 1990 there were approximately 15,623 cases of counterfeiting reported from 91 countries worldwide, namely 0.5 per 100,000 population; some 7,000 (namely 45%) were claimed to have been resolved.
It has been estimated that for every 1 million American notes in circulation, 500 is counterfeit. In 1993 USA authorities seized some US$140 million in counterfeit bills, considered to be only a fraction of those in existence. Very high quality counterfeit bills cost the Federal Reserve of USA several million dollars in 1993 when for several months it was obliged to suspend the policy of charging back to all member banks the cost of counterfeits it had detected.