Federal Act on Banks and Savings Banks in the context of Law of Switzerland

Banking secrecy, alternatively known as financial privacy, banking discretion, or bank safety, is a conditional agreement between a bank and its clients that all foregoing activities remain secure, confidential, and private. Most often associated with banking in Switzerland, banking secrecy is prevalent in Luxembourg, Monaco, Hong Kong, Singapore, Ireland, and Lebanon, among other off-shore banking institutions.

Otherwise known as bank–client confidentiality or banker–client privilege, the practice was started by Italian merchants during the 1600s near Northern Italy (a region that would become the Italian-speaking region of Switzerland). Geneva bankers established secrecy socially and through civil law in the French-speaking region during the 1700s. Swiss banking secrecy was first codified with the Banking Act of 1934, thus making it a crime to disclose client information to third parties without a client's consent. The law, coupled with a stable Swiss currency and international neutrality, prompted large capital flight to private Swiss accounts. During the 1940s, numbered bank accounts were introduced creating an enduring principle of bank secrecy that continues to be considered one of the main aspects of private banking globally. Advances in financial cryptography (via public-key cryptography) could make it possible to use anonymous electronic money and anonymous digital bearer certificates for financial privacy and anonymous Internet banking, given enabling institutions and secure computer systems.

Banking in Switzerland dates to the early 18th century through Switzerland's merchant trade and over the centuries has grown into a complex and regulated international industry. Banking is seen as very emblematic of Switzerlandand the country has been one of the largest, if not largest, offshore financial centers and tax havens in the world since the mid-20th century, with a long history of banking secrecy, security and client confidentiality reaching back to the early 1700s. Starting as a way to protect wealthy European banking interests, Swiss banking secrecy was codified in 1934 with the passage of a landmark federal law, the Federal Act on Banks and Savings Banks. These laws were used to protect assets of persons being persecuted by Nazi authorities but have also been used by people and institutions seeking to illegally evade taxes, hide assets, or to commit other financial crime.

Controversial protection of foreign accounts and assets during World War II sparked a series of proposed financial regulations seeking to limit bank secrecy, but with little resulting action. Despite various international efforts to roll back banking secrecy laws in the country which were largely minimized or reverted by Swiss social and political forces, in 2017 Switzerland agreed to "automatic exchange of information" (AEOI) with foreign governments and their revenue services regarding information of depositors not resident in Switzerland. This constituted de facto the end of Swiss banking secrecy for depositors who were not Swiss residents. Furthermore, after Switzerland ratified the Foreign Account Tax Compliance Act agreement with the United States, because of concerns regarding their tax liability (the U.S. taxes its citizens regardless of whether they are resident in the U.S. or not) some Swiss banks have gone so far as to close accounts held by US citizens, and to ban the opening of new accounts by US citizens and by dual US-Swiss citizens, including those deemed lawful permanent Swiss residents. Thus banking secrecy remains in force only for those residing in and solely taxable in Switzerland.

Numbered bank accounts are bank accounts wherein the identity of the holder is replaced with a multi-digit number known only to the client and selected private bankers. Although these accounts do add another layer of banking secrecy, they are not completely anonymous as the name of the client is still recorded by the bank and is subject to limited, warranted disclosure.

During the 1910s, bankers from Switzerland created numbered bank accounts to add a layer of anonymity for European clients seeking to avoid paying World War I taxes. With the passage of the Swiss Banking Law of 1934, this practice proliferated across the banking industry in Switzerland. Some Swiss banks supplement the number with a code name such as "Cardinal", "Octopussy" or "Cello" as an alternative manner to identify the client. However, to open this type of account in Switzerland, clients must pass a multi-stage clearance procedure and prove to the bank the lawful origins of their assets. Banking institutions that have adopted this practice in Europe, Asia, and the Americas also require clients to undergo stringent vetting and provide the identity of the beneficial owner. The usage of fake names to open these accounts is prohibited in Switzerland, the European Union, the United States, and other off-shore financial centers.