Tax amnesty is a limited-time opportunity for a specified group of taxpayers to pay a defined amount, in exchange for forgiveness of a tax liability (including interest and penalties) relating to a previous tax period or periods and without fear of criminal prosecution. It typically expires when some authority begins a tax investigation of the past-due tax. In some cases, legislation extending amnesty also imposes harsher penalties on those who are eligible for amnesty but do not take it. Tax amnesty is one of voluntary compliance strategies to increase tax base and tax revenue. Tax amnesty is different from other voluntary compliance strategies in part where tax amnesty usually waives the taxpayers' tax liability.