3자간 등기명의신탁과 명의수탁자의 처분으로 인한 부당이득반환 관계 - 대법원 2021. 9. 9. 선고 2018다284233 전원합의체 판결을 중심으로 -

In a case where the obligation to register a complete transfer of ownership was impossible due to the arbitrary disposal (establishment of a mortgage) of the trust property by the nominal trustee to a third party in a three-party registered trust, and the sale of the trust property by the seller to the buyer and nominal trustor resulted in the cancellation of the mortgage registration, the majority opinion of the subject judgment affirmed the nominal trustor’s claim for the return of unjust enrichment equivalent to the secured debt amount against the nominal trustee, while the minority opinion denied this. However, assuming that the three-party registered trust is basically a case of shortened payment by instruction, the buyer and nominal trustor is deemed to have transferred the transfer registration of ownership of the trust property inherited from the seller back to the nominal trustee, and thus the transfer registration of ownership of the trust property from the nominal trustor to the nominal trustee has been completed, which is a ‘payment’ in the case of unjust enrichment. Meanwhile, since the obligation to return the original property (register transfer of ownership for trust real estate for which the registration of establishment of mortgage has been cancelled) as a return of unjust enrichment has become impossible to perform in terms of social norms due to arbitrary disposal (establishment of mortgage) of trust real estate to a third party under the Real Estate Real-Name System Act, the nominal trustee has an obligation to pay the nominal trustor an amount equivalent to the secured claim of the mortgage established on the trust real estate as a return of value as a return of unjust enrichment. In addition, the trustee who is the nominal holder of the invalid transfer of ownership registration regarding the trust property has the obligation to cancel the transfer of ownership registration in the trustee’s name to the seller who is the owner, in the case of arbitrary disposal (establishment of mortgage) of trust real estate to a third party, the trustee has the obligation to cancel the transfer of ownership registration in the trustee’s name or to register the transfer of ownership in the seller’s name, which must be completed in a state where the mortgage registration in the third party’s name has been canceled, and this obligation has become impossible to perform in terms of social norms, since this constitutes an infringement of the seller’s ownership rights, which are exclusive allocation benefits from unjust enrichment, the nominal trustee has an obligation to pay the seller the amount equivalent to the secured claim of the mortgage established on the trust property as return of unjust enrichment. And the obligations of these trustees to return unjust enrichment to the trustee and seller overlap to the extent that they are in a joint and several debtor relationship.