To exercise the taxing right, the tax authority should determine whether an individual or company is a taxpayer in Korea and this is a work of determining a resident for tax purposes. If a taxpayer is determined as a resident in Korea, he or she will be liable to pay tax within the Korean tax jurisdiction for his/her worldwide income. The determination of residence requires physical stays for a certain period in Korea. Thus, if a resident emigrates out of the jurisdiction before realizing gains derived from assets he/she possessed for either the tax evasion purpose or legitimate purpose, it will be doubtful whether the Korean tax authority should give up exercising the taxing right to the emigrant.
It is required for the tax authority to exercise its taxing right on appreciation in value of property accumulated for a period when a taxpayer resides in Korea even if the income is not realized. Furthermore, it is also a just measure to defeat tax evasion which abuses non-residence status.
To resolve the problems, many countries adopted and have operated the exit tax regime. The regime exists with several forms but it is generally defined as a taxation that imposes capital gains tax on the difference between the purchased and sale price (FMV) of an asset a taxpayer possessed. Here, it is usually deemed that the taxpayer disposes his/her assets at the time when the taxpayer gives up his/her residence of a country and achieves it in another country.
As taxation on unrealized income, however, the exit tax has a potential to violate the Constitution by limiting the taxpayers" rights to property, equality, and freedom of residential mobility guaranteed by the Constitution. Consequently, if the introduction of the exit tax has legitimate and reasonable purposes such as securing taxing rights and counteracting against tax avoidance, legislators can introduce it with the constitutional justification.
Moreover, to justify the adoption of the exit tax regime, the followings should be considered. First, the payment of tax should be deferred until the actual disposition arises in the immigration country for a taxpayer to get actual funds to pay the tax. Second, the proceedings with regard to deferring the exit tax payment must be taken in the least restrictive way. Finally, any decrease in value that occurs after emigration has to be taken into account when calculating the final tax bill, unless the country of immigration does not have appropriate measures.
If the above considerations for adopting the exit tax meet the constitutional requirements, the comprehensive exit tax regime will be the right form when it is enacted. That is, if a taxpayer emigrates out of the jurisdiction, his/her all assets he/she possessed at the time of emigration should be subject to the exit tax. In addition, a legislation bill similar to that of Canada will be justifiable if it excludes assets that are located in the Korean tax jurisdiction and not subject to the exit tax in nature.
More importantly, double taxation arisen where the assets subject to the exit tax are actually disposed should be relieved by allowing foreign tax credit, the reverse tax credit for the emigrant. However, for the long term, if a contracting state operates the exit tax regime, it will be required to amend the relevant provision of a tax treaty by negotiation between the treaty parties in which needs to re-estimate the purchase price for an asset that an emigrant possessed and relocated it into the other contracting state.