Division of the Matrimonial Property and Performance for Illegal Cause

The Supreme Court decision on October 16, 2025 (cases 2024므13669, 13676) dealt with the divorce and division of the matrimonial property between a chaebol group chairman and a former president's daughter, which attracted significant public attention. The Court held that even if the former president had provided approximately 30 billion won to the chaebol chairman's father around 1991, claiming that this constituted a contribution to matrimonial property formation is equivalent to requesting the return of a performance for illegal cause, and therefore cannot be permitted. In contrast, the lower court in that case held that receiving financial support from the president around 1991 could not itself be regarded as a performance for illegal cause, and also that such act by the chaebol chairman's father at that time did not constitute any criminal offense, meaning that receiving such financial support was not subject to criminal punishment and therefore was not considered as a performance for illegal cause. This article examines whether the Supreme Court's judgment is reasonable. First, regarding the raison d'etre of the probihibition of the return of a performance for illegal cause, the theory of general prevention or deterrence is considered the most reasonable. As for determining whether it qualifies as a performance for illegal cause, it should be determined based on whether not allowing the return of unjust enrichment aligns with the purpose of prohibiting such actions. And if, after the Enforcement of the Act on Regulation and Punishment of Criminal Proceeds Concealment on September 28, 2001, the President gave money acquired through dishonest means to another person as a gift, this should be regarded as a performance for illegal caus. The previous Supreme Court precedents also hold this view. Furthermore, even before the Enforcement of the Act on Regulation and Punishment of Criminal Proceeds Concealment, if, as in this case, a person who received a bribe gave it as a gift to someone who was aware of this fact, it would be reasonable to consider it as a performance for illegal caus. Money laundering acts that disguise the proceeds of crime as legitimate funds inherently promote crime and are undeniably harmful to society. Receiving criminal proceeds, like acquiring stolen goods, possesses harmful characteristics. However, as stolen goods refer to property illegally obtained through property crimes, so before the enforcement of the Act on Regulation and Punishment of Criminal Proceeds Concealment, it could not be punishable. Therefore, the absence of a law directly regulating this can be seen as a legal vacuum. Nevertheless, the provision of public policy under Article 103 of the Civil Act serves to supplement this incompleteness of statutory law. Meanwhile, Article 746 of the Civil Code, which stipulates the principle of the probihibition of the return of a performance for illegal cause, together with Article 103 of the Civil Code, serves as a fundamental expression of a major ideal underlying private law. It not only prohibits the return of unjust enrichment but also applies in cases such as exercising real rights or claiming damages for torts. Therefore, even if a spouse contributed to the accumulation of the other spouse's assets, if that contribution is based on a performance for illegal cause, it should not be allowed to claim a division of the matrimonial property.