Under the banking confidentiality rules, for instance, a bank is not allowed to certify that somebody has or has not been a customer of the bank. Swiss banking confidentiality is in no way absolute. Since banking confidentiality derives from a contractual agreement, it can be lifted whenever the customer so chooses with a valid waiver. It may also be lifted if a Swiss court issues a lifting order in a criminal, civil, or legal assistance proceeding. Swiss banking confidentiality is strict in safeguarding a customer's privacy but it is not intended to protect criminals.
Banking confidentiality is lifted in cases of Swiss criminal investigations.
It may also be lifted in the course of providing international legal assistance in criminal matters, including foreign criminal investigations of money laundering and insider trading, in cases of tax fraud and in other cases indicated in the previous paragraph. Switzerland has a long tradition of granting legal assistance in criminal matters. For instance, in 1973 Switzerland took the lead as the first country in continental Europe to negotiate a treaty on mutual legal assistance with the United States of America. At the same time, this treaty was the first treaty which contained detailed provisions on fighting organized crime with all means available. Recent examples of the lifting of Swiss banking confidentiality in the course of mutual legal assistance include the case of the brother of former Mexican President Salinas.