Bank secrecy was invented by the 1934 Swiss Banking Act following a public scandal in France, when MP Fabien Alberty denounced tax evasion by eminent French personalities, including politicans, judges, industrialists, church dignitaries and directors of newspapers, who were hiding their money in Switzerland. He called these men of "a particularly ticklish patriotism", who "probably are unaware that the money they deposit abroad is lent by Switzerland to Germany". The Peugeot brothers and François Coty, of the famous perfume family, were on his list. Since then, Swiss banks have acquired world-wide celebrity due to their anonymous numbered bank accounts, which critics such as ATTAC NGO alleged only help legalized tax evasion, money laundering and more generally the underground economy.

Under the principle of bank secrecy, privacy is statutorily enforced, with Swiss law strictly limiting any information shared with third parties, including tax authorities, foreign governments or even Swiss authorities, except when requested by a Swiss judge's subpoena [citation needed]. However anonymous banking is not strictly true as a term as all Swiss bank accounts, including numbered bank accounts, are linked to an identified individual under Swiss banking law. This law only permits a bank to share information with others in cases of severe criminal acts, such as identifying a terrorist's bank account [citation needed]. Any bank employee violating a client's privacy is punished quite severely by law. Many offshore banks, located in tax havens such as in the Cayman Islands and Panama, also have strict privacy laws.

http://www.swiss-privacy.com/bank-secrecy.html#Swiss_Banking_Act_of_1934