According to Articles 2(1), 2(3) and (4), and 3 of the former Interest Limitation Act (amended by Act No. 10925, Jul. 25, 201; hereinafter “Interest Limitation Act”), and “the maximum interest rate under Article 2(1) of the Interest Limitation Act”, the maximum interest rate under a contract for monetary lending is 30% per annum; the contractual interest is more than the above maximum interest rate under a contract; and where an obligor has voluntarily paid interest exceeding the above maximum interest rate, the amount equivalent to the excess interest paid shall be appropriated for the original, and where the original is extinguished, the return thereof may be claimed.

The judgment below

According to the reasoning, the court below recognized the fact that the defendant agreed with C to receive 20% or 25% interest at intervals of 35 to 40 days, which is the highest interest rate stipulated in the Interest Limitation Act, from April 16, 2007 to May 27, 2008, and C borrowed a total of KRW 1,02,70 million from May 25, 2007 to May 21, 2008, and received KRW 1,79,270,000,00 as the principal interest, from May 25, 2007 to May 21, 2008. Accordingly, even if C arbitrarily paid the interest to the defendant exceeding the highest interest rate stipulated in the Interest Limitation Act, the amount equivalent to the interest paid should be appropriated to the principal, and as long as it appears to have expired, C can claim the return of the principal and interest from the defendant under the Interest Limitation Act.

Nevertheless, the lower court, on the ground that C voluntarily pays interest exceeding the interest rate specified in the Interest Limitation Act, and on the ground that the return of the interest is not possible even if the payment of such interest is null and void, again paid the excess amount against the Defendant.