부당이득으로서 운용이익의 반환 - 미국 "(제3차) 원상회복 및 부당이득법 리스테이트먼트"와의 비교를 중심으로

Could “consequential gains” profits obtained by a restitution defendant through separate acts of operation, such as disposition, use, or investment of the claimant’s property that the defendant has unjustly acquired or interfered with fall within the scope of restitution for unjust enrichment under Article 747(1) of the Korean Civil Act? “Consequential gains” often exceed the objective market value or the ordinary rental value of the original property, and in Korea, there is an ongoing debate as to whether the defendant must return all such gains to the claimant on the ground that they derive from the claimant’s property, or whether the defendant may retain them on the basis that they result from the defendant’s own independent acts of operation. The Korean Supreme Court, based on the traditional “loss-based limitation theory”, which holds that the scope of restitution by the defendant is limited to the extent of the damage suffered by the claimant, maintains that consequential gains are not subject to restitution unless they fall within the range of the claimant’s loss “the profits that the claimant would ordinarily have earned from the property even without the defendant’s intervention”, typically measured by the property’s ordinary market, rental, or use value. This position, however, has been the subject of considerable criticism in Korean academia. In this context, a comparative examination of the Restatement (Third) of Restitution and Unjust Enrichment , published in 2011 by the American Law Institute to systematically organize U.S. unjust enrichment law, yields several important insights. The Restatement, under the heading “Liability in Restitution” in Part II, classifies various circumstances in which restitutionary liability may arise and provides specific rules and comments tailored to each category. This approach reflects an attempt to explain the law of unjust enrichment through a unified general principle while, at the same time, addressing each type with due regard to its particular characteristics, thereby striking a balance between uniformity and individuality. In Korea, too, a longstanding debate has persisted between the “unified theory” and the “typological approach” concerning the foundation and nature of unjust enrichment. Classifying unjust enrichment according to its nature and causes, as the Restatement does, and examining each category from a differentiated analytical perspective, allows for a more reasonable and precise understanding of the elements and legal consequences of each category of unjust enrichment. In Section 1 of Part I, the Restatement sets forth a fundamental principle of restitutionary liability, stating that “A person who is unjustly enriched at the expense of another is subject to liability in restitution.” With respect to the phrase “at the expense of another”, the accompanying comments clarify that when a person obtains a benefit by violating another’s legally protected right, the claimant need not separately prove any loss. Furthermore, Section 3 of the Restatement declares that “A person is not permitted to profit by his own wrong”, thereby establishing a basis for disgorgement when a conscious wrongdoer has obtained profits exceeding the provable loss suffered by the claimant. In contrast, the prevailing view and the Supreme Court of Korea have maintained that “damage to the claimant” is a required element for all forms of unjust enrichment. However, it is inappropriate to uniformly treat “damage to the claimant” as a necessary element and a standard for limiting the scope of restitution across all categories of unjust enrichment. Meanwhile, it is also worth noting that the comments to Section 1 of the Restatement clearly emphasize the distinction between the law of unjust enrichment and the law of torts. While tort law seeks to compensate the victim for the harm suffered, the fundamental purpose of unjust enrichment law is to correct the defendant’s unjust gain. Accordingly, in the context of unjust enrichment, it is the benefit obtained by the defendant that forms the basis for restitution, and it is not necessary to determine the scope of restitution by reference to the claimant’s damage. In Part III, Chapter 7, Topic 1, the Restatement addresses restitution via money judgment. It broadly distinguishes between cases of unjust enrichment arising from misconduct and those that do not, and it sets different standards for measuring enrichment depending on whether the defendant is innocent, conscious, or at fault. In particular, the Restatement provides that when a conscious wrongdoer earns net profits exceeding the market value of the original benefit obtained through the misconduct, the wrongdoer must disgorge the full amount of profits attributable to the underlying wrong, and this liability is not limited by the amount of loss suffered by the claimant. The scope of disgorgement also extends to “consequential gains”, so long as those gains are not unduly remote from the misconduct. Notably, the Restatement’s emphasis on the need to deter wrongful conduct by conscious wrongdoers, and its recognition that the complete disgorgement of gains derived from such conduct constitutes an important objective of the law of unjust enrichment, carry significant implications for Korean law. When a defendant knowingly and intentionally interferes with another’s property without legal justification or authority, the defendant’s exploitation of that property cannot be regarded as lawful or legitimate. In such cases, as the gains are obtained through the defendant’s deliberate violation of the claimant’s property rights, it would be inappropriate to allow the defendant to retain them. Rather, there arises a policy-based need to actively remove or strip such profits from the wrongdoer. However, even when the defendant has obtained profits through intentional infringement or other wrongful conduct, some of those profits may not be directly related to the wrongful conduct or the infringed right, and requiring the return of all such profits could result in the claimant receiving an unjust windfall. Therefore, determining which profits should be subject to restitution and which should not is a difficult but critically important task. In this regard, the Restatement sets forth a variety of standards and considerations for identifying the extent to which the defendant’s profits are attributable to the underlying wrong. Korea, likewise, should further develop its legal doctrine for reasonably delineating the scope of restitution of consequential gains through deeper scholarly analysis of these issues.