Coins minted for payment transactions are circulation coins. Their value is guaranteed by the issuing governmental or supranational organisation. In most cases the nominal value of the coins is lower than the metal value, unlike investment coins. However, circulation coins can become investment coins, as is the case with many gold coins, for example from the former German Empire. In the EU, the condition for circulation coins to be traded as tax-exempt bullion coins is that the coins have a purity of at least 900/1000 and were minted after 1800.