Under the Internal Revenue Code, a "U.S. person" (including United States citizens and U.S. permanent residents) is taxed on his or her worldwide income regardless of place of residence. U.S. persons can avoid U.S. tax liability on non-U.S. source income only by moving abroad, renouncing citizenship (or terminating or losing permanent residence), documenting that renunciation/termination/loss, and (as often required) formally exiting the U.S. tax system via IRS Form 8854. Exiting high net worth and high income individuals may owe an expatriation tax. However, if they continue to receive income from any U.S. sources, they will still be liable for U.S. taxes, often on a tax withholding basis and sometimes with less favorable tax rates (such as dividend tax rates). U.S. states and municipalities with their own tax systems sometimes have different exit rules.