A tax paradise (tax haven) is a country, state or territory where certain taxes are levied at a low rate or not at all while offering due process, good governance, a low corruption rate and, frequently, numbered accounts for bank secrecy purpose. Individuals and/or corporate entities can find it attractive to move themselves to areas with reduced or nil taxation levels. In business this is called off shore banking

Numbered bank accounts, used by Swiss banks and other offshore banks located in tax havens, have been accused by NGOs such as ATTAC of being a major instrument of the underground economy, facilitating tax evasion and money laundering.

Wikipedia on tax havens and bank secrecy >>>