1. The defendant shall pay 3,351,500 won to the plaintiff and 951,500 won from June 25, 2008, and 2,400,000 won to the plaintiff.

1. Basic facts

A. On June 25, 2008, the Plaintiff received a loan of 400 million won from the Plaintiff, and the Plaintiff created a right to collateral security on the commercial building No. 301, Yongsan-gu, Yongsan-gu (hereinafter “instant commercial building”) to the Defendant.

(2) At the time of the instant loan contract, the Plaintiff and the Defendant agreed to apply the term of the loan contract to June 25, 201, and the interest rate to the rate of 0.2% lower than the standard interest rate as the floating interest rate.

Since then, the defendant calculated as a variable interest rate in proportion to the standard interest rate, and received interest from the plaintiff.

B. Since then, the Plaintiff lost the benefit of the term of the instant loan agreement due to the delinquency in payment of interest, and the Defendant applied for voluntary auction of the instant commercial building to the Jung-gu District Court C on June 4, 2012.

In the above auction procedure, the sales price of this case was 415,378,000 won, which was decided to permit the sale of the commercial building in this case. D paid in full and completed the registration of ownership transfer on the commercial building in this case on January 9, 2013.

[Reasons for Recognition] Gap's evidence Nos. 1, 2, 4, Eul's evidence Nos. 1 to 4, 11, and 12, the purport of the whole pleadings

2. The assertion and judgment

A. The Defendant asserted that the Plaintiff claimed the return of unjust enrichment (Article 1-A) 1 was paid the interest on the instant loan by changing the interest rate in proportion to the standard interest rate set by the Bank of Korea. While the CD interest rate sharply drops from November 2008 due to the global financial crisis, the standard interest rate is applied as it is, and the Defendant’s failure to adjust the interest rate lower than the CD interest rate is null and void as it used a superior transaction position without reflecting the market situation, and thus, the Defendant’s failure to adjust the interest rate lower than the CD interest rate is deemed to have been conducted an unfair transaction by using a superior transaction position. Therefore, the difference between the interest that the Defendant received if the Defendant applied to the instant loan contract by adjusting the lower ratio of the CD interest rate from