The tax liability influences in a substantial manner the economic behaviour of households and firms. Efforts to reduce the tax burden can gain the form of tax planning, tax avoidance and tax evasion.
When applying the lawful tax optimization, many possibilities which are enabled by particular provisions of the law are used, whereas in the case of abuse of rights and circumvention of law, the actions leading to the reduction of the tax duty are performed only "apparent" or they serve as an instrument for the intentional circumvention of another norm. The use of tax havens as an instrument for tax optimization means searching for positive differences among tax systems of different countries.
They are subsequently used for the reduction of the tax burden of commercial and similar activities.