The appeal is dismissed.

The costs of appeal are assessed against the defendant.

The grounds of appeal are examined (to the extent of supplement in case of supplemental appellate briefs not timely filed).

1. The system of unjust enrichment is a system that orders an acquirer of property value to return a certain amount of property value in a case where the change in property value among the parties seems to be justifiable in a general form, but it is judged that the change in property value between them is unjust from a relative and substantial perspective

(See Supreme Court en banc Decision 2014Da5531 Decided June 25, 2015). 2. Reviewing the reasoning of the lower judgment and the record reveals the following facts.

(1) A, while working as the director of the Plaintiff’s branch division, embezzled and commercialized the Plaintiff’s certificate of deposit with his accomplice, requested the Defendant to open an account under the name of F Co., Ltd. (hereinafter “F”) and deposited part of the amount of embezzlement in the said account.

In the process of withdrawing the above deposit between May 10, 2005 and July 12, 2005, A, etc. deposited KRW 2,50 million into the Defendant’s special deposit account with the cash issuing cashier’s checks, and issued 25 copies of the cashier’s checks listed in the attached list of the judgment below (hereinafter “instant cashier’s checks”).

(2) Around July 27, 2005, the Plaintiff reported the instant cashier’s checks to the Defendant, and around that time, the Defendant suspended the payment of KRW 2,050,000,000 for the issued funds.

The defendant is not entitled to exercise the right to the cashier's checks of this case or the right to claim reimbursement of benefit in the event that the respective period of presentation for payment for the cashier's checks of this case has expired and the ten years have passed since the respective period of presentation for payment for the cashier's checks of this case.

(3) The Defendant, upon receiving the Plaintiff’s accident report, was aware that the source of the issued fund is embezzlement, and thus suspended payment.