1. The plaintiff's appeal is dismissed.

2. The costs of appeal shall be borne by the Plaintiff.

Purport of claim and appeal

The first instance court.

1. On February 26, 2015, the Plaintiff asserted that he/she transferred KRW 20 million to C among the customers, but mistakenly, he/she transferred KRW 20 million to the account of the other transaction partner B.

B On March 4, 2015, the Defendant requested the Defendant to set off his/her overdue loan and the above KRW 20 million, but requested the Defendant to set off and withdraw the set-off for one hour after receiving the Plaintiff’s request. However, the Defendant rejected the request for the withdrawal of set-off.

Since the defendant's set-off is a violation of the principle of good faith and is abuse of the right of set-off, the defendant is obligated to return the amount of undue profits to the plaintiff.

2. The Plaintiff’s transfer of KRW 20 million to the Defendant Bank’s deposit account on February 26, 2015 is no dispute between the parties.

However, barring any special circumstance, in a case where a remitter enters into the ledger of a deposit by transferring funds to a bank account of an addressee pursuant to the basic terms and conditions of deposit transaction, barring any special circumstance, a deposit contract equivalent to the above deposit amount is established between the remitter and the receiving bank regardless of whether there exists a legal relationship between the remitter and the recipient, and the receiving bank acquires deposit claims equivalent to the above deposit amount from the receiving bank (see, e.g., Supreme Court Decision 2007Da51239, Nov. 29, 2007). The receiving bank, in principle, has no duty to investigate whether the money deposited into the account of the payee is deposited without the cause of the transfer of funds due to mistake of the remitter, and it is valid to offset the amount of money deposited to the payee’s account with automatic bonds by the recipient’s loan claims, etc. constitutes a violation of the good faith principle or an abuse of rights, barring special circumstances.

(Supreme Court Decision 2007Da66088 Decided May 27, 2010). In the instant case, even if the Plaintiff’s remittance was based on mistake, B made unjust enrichment by acquiring a deposit claim equivalent to the amount deposited against the Defendant bank.