Bank Secrecy – In most countries one of the terms of the relationship between banker and customer is that the banker will keep the customer’s affairs secret. Staff members are normally required to sign a declaration of secrecy as regards the business of the banks. Where numbered accounts are used their purpose is to limit the number of persons who know the identity of the client. In certain countries (e.g. Switzerland and the Cayman Islands) specific legislation makes breaches of bank secrecy subject to criminal law sanctions. However, in all legal systems (including Switzerland) there are specific cases where the duty of secrecy of a banker is discharged, e.g. where fraud, money laundering and narcotics are involved. The exchange of information clause contained in most tax treaties may enable the tax administration of one treaty country to obtain information concerning bank accounts which its residents have in the other country.