Numbered bank accounts are offered by Swiss banks to the majority of their clients. Typically the account will also have a codename attached to it for the convenience of both the banker and customer. This avoids confusion between banker and customer as to which account is being discussed. The feature of numbered accounts is that the customer’s name does not appear on bank statements. Only the number and code-name appear. This means that if bank statements are lost or stolen, it will not be immediately obvious as to who is behind the account.

Although numbered accounts may seem to grant some anonymity, Swiss law now requires all banks to know the identity of their customers. However, in the case of a numbered account, the customer’s identity will only be known to a small group of people in the bank, on a “need to know” basis. Also the customer’s name does not appear on the bank’s computer thus preserving confidentiality in the case of cybercrime.

Numbered accounts may not be used to hide the proceeds of a crime. For example, Swiss banks have strict anti-money laundering rules and laws which require the reporting of suspected cases to the Swiss authorities. Still, numbered accounts have been used for criminal activities, such as corrupt politicians hiding money embezzled from citizens. While it is unknown how complicit Swiss banks were in such activities, they have cooperated with subsequent governments to return the funds to the country concerned, such as the fortune of Ferdinand Marcos.

Numbered accounts also have more mundane uses such as hiding funds from spouses, family members, and others who would potentially try to take funds away from the owner. In some countries this might include criminals, kidnappers and blackmailers, whilst in others it may include unknown persons who might potentially sue, e.g. in a malpractice suit. Numbered accounts are also used for tax evasion, but following the imposition of a 15% withholding income tax on interest earned by EU residents, the perceived tax benefits have been somewhat diminished.