Prepaid Interest Deduction in South Korea
이 글의 한국어 원문: 선이자를 떼고 받은 대출, 원금은 얼마인가요
Is the Principal the Face Amount or the Money Actually Received?
Contents
- 1. What did the Supreme Court of Korea reverse in the prepaid interest cases?
- 2. Why does Article 3 use the word "principal" twice?
- 3. How does the calculation work with actual numbers?
- 4. Which interest rate ceiling applies to my contract?
- 5. Can a lender avoid the ceiling by calling the charge a fee?
- 6. What if the lender deducts unpaid interest on an earlier loan?
- 7. How is the character of that deduction determined?
- 8. Can excess interest be revived by rewriting the promissory note?
- 9. Why does this calculation matter in fraudulent transfer litigation?
A borrower agrees to a loan of 100 million Korean won. What arrives in the account is 90 million won. The lender explains that one month of interest, 10 million won, was taken out in advance. So what is the principal this borrower must repay: 100 million won, or 90 million won?
Neither. The Supreme Court of Korea calculated 92.25 million won, and reversed a lower court that had arrived at 82.25 million won. The gap between the two figures is exactly 10 million won.
Article 3 of the Interest Limitation Act (Isaje-hanbeop) is a single sentence, but the word “principal” appears in it twice, and the two references point to different amounts. Courts that miss this get the arithmetic wrong. The Supreme Court of Korea has reversed lower courts on precisely this point in 2012, in 2021, and again in 2023. For foreign investors, lenders, and companies extending or receiving credit in South Korea, the distinction determines how much is actually owed.
What did the Supreme Court of Korea reverse in the prepaid interest cases?
The decision of March 25, 2021 (2020Da289989) arose from a fraudulent transfer action, known in Korean practice as sahaehaengwi chwiso, in which a creditor seeks to set aside a debtor’s disposition of assets. To bring such a claim the creditor must establish the amount of the secured claim, and here that claim was a loan disbursed net of prepaid interest. The Supreme Court reversed on two grounds.
The first was a violation of the principle of party presentation. The lower court proceeded on the basis that the loans totaled 320 million won, although the plaintiff had never made that assertion. The Supreme Court held that finding and ruling upon a principal fact that no party has asserted violates the principle of party presentation.
The second ground is the subject of this article. For computational convenience, the lower court had treated the amount deducted in advance as interest exceeding the statutory ceiling as though it were a repayment received from the borrower on the day of disbursement. The Supreme Court held that this reflected a misunderstanding of the law on applying excess prepaid interest against principal, and remanded the case to the Suwon District Court.
Why does the shortcut fail? On the day of disbursement no time has elapsed, so no interest has accrued. Treating the deduction as a same-day repayment leaves no interest for it to be applied against, so the entire deduction goes straight to principal. That erases the step the statute requires, namely that lawful interest computed on the amount actually received is first satisfied. A convenience in arithmetic quietly deleted a step Parliament had written into the statute.
Why does Article 3 use the word "principal" twice?
Article 3 of the Interest Limitation Act provides that where interest has been deducted in advance, if the deduction exceeds the amount calculated at the maximum interest rate under Article 2(1) using the sum actually received by the debtor as the principal, the excess is deemed to have been applied against the principal. The word appears twice, and the two occurrences are not the same figure.
| Position in the provision | Function | Which amount |
|---|---|---|
| First, "using … as the principal" | The base for computing lawful interest | The sum the borrower actually received |
| Second, "applied against the principal" | The target reduced by the excess | The agreed principal before the deduction |
The Supreme Court has stated the second point expressly. In a case governed by the Act on Registration of Credit Business (the Credit Business Act), which is structured the same way, the Court held that any excess is applied against the loan principal agreed between the parties before the deduction of prepaid interest, and that what remains after that application becomes the principal the debtor must repay at maturity (Supreme Court of Korea, November 16, 2023, 2023Da266390).
In short, the net amount received is a measuring stick for lawful interest, while the amount reduced is the face principal. Subtracting the excess from the net amount would count the same deduction twice.
How does the calculation work with actual numbers?
The leading authority is the decision of October 11, 2012 (2012Da55198). The facts are straightforward. A lender agreed to lend 100 million won at 10 percent per month, deducted one month of interest amounting to 10 million won at disbursement, and handed over 90 million won. The applicable ceiling at the time was 30 percent per year.
| Step | Calculation | Amount |
|---|---|---|
| Lawful one-month interest on the net amount | 90,000,000 × 30% × 1/12 | 2,250,000 won |
| Prepaid interest deducted | — | 10,000,000 won |
| Excess over the ceiling | 10,000,000 − 2,250,000 | 7,750,000 won |
| Principal after application | 100,000,000 − 7,750,000 | 92,250,000 won |
The Supreme Court held that of the 10 million won deducted as prepaid interest at disbursement, 2.25 million won, being one month of interest at the statutory ceiling of 30 percent per year on the 90 million won actually received, was satisfied as interest, and that the remaining 7.75 million won was applied against the principal of 100 million won.
The lower court had subtracted the same 7.75 million won from the net amount of 90 million won, reaching 82.25 million won, and was reversed. The difference between the two results is exactly 10 million won, the full amount of the deduction, because the deduction was counted once in the net figure and again as the excess.
The 2.25 million won is not lost. It is interest the lender lawfully retains. The Interest Limitation Act does not void interest as such; it voids only the portion above the ceiling.
Which interest rate ceiling applies to my contract?
The 30 percent figure applied because the loan was made in 2008. Article 2(2) of the Interest Limitation Act provides that the maximum interest rate means the rate in force at the time of the agreement. The rate to look up is therefore the one in effect on the date the loan was agreed, not the rate in force today.
| Period | Ceiling | Source |
|---|---|---|
| June 30, 2007 to July 14, 2014 | 30% per year | 2012Da55198; 2020Da289989 |
| July 15, 2014 to February 7, 2018 | 25% per year | Presidential Decree No. 25376; 2022Da286144 |
| February 8, 2018 to July 6, 2021 | 24% per year | Presidential Decree No. 28413; 2022Da286144 |
| July 7, 2021 to the present | 20% per year | Presidential Decree No. 31593, amended April 6, 2021 |
The current decree sets the maximum contractual interest rate for monetary loans at 20 percent per year. The supplementary provisions of each amending decree apply the new rate to contracts concluded or renewed on or after the effective date, so whether an older loan was renewed at some point must also be checked.
Applying today’s 20 percent to an older loan understates the principal, while applying the historical 30 percent to a recent contract overstates it. The date of the agreement has to be fixed before any calculation begins.
Can a lender avoid the ceiling by calling the charge a fee?
No. Article 4(1) of the Interest Limitation Act provides that anything a creditor receives in connection with a monetary loan is deemed to be interest, regardless of whether it is labeled a gratuity, a discount, a commission, a deduction, an advance payment, or anything else. The provision looks past the label.
The Supreme Court applied this to an amount deducted as an introduction fee, holding that even under that label, if the amount relates to the loan between creditor and debtor and can be regarded as consideration for the loan, it is deemed to be interest, and that a creditor who deducts it from the loan in advance has made a deduction of prepaid interest (Supreme Court of Korea, September 30, 1997, 97Da24023).
Brokerage commissions and notarization fees are treated the same way. Where a lender arranged for the borrower to pay the broker directly while paying the broker nothing itself, the Court found that the lender had shifted its own cost to the borrower, making the amount consideration for the loan and therefore interest (Supreme Court of Korea, November 13, 2014, 2014Da24785, 24792, 24808).
Article 4 is not, however, a rule that every amount withheld is interest. In an en banc decision the Supreme Court restated the test, explaining that the purpose of the provision is to prevent evasion, so that anything connected to the loan and capable of being regarded as consideration for it is deemed interest, while holding that a prepayment fee is not deemed interest because it cannot readily be regarded as consideration for the loan (Supreme Court of Korea, September 18, 2025, 2023Da221885, en banc). The majority reasoned that a prepayment fee is liquidated damages for early repayment.
The operative question is always the same: is the amount consideration for the loan?
What if the lender deducts unpaid interest on an earlier loan?
This structure appears constantly in practice. Principal and accrued interest remain outstanding on a first loan. The lender then advances a second loan, withholds part of it, hands over the balance, and records the withheld amount as payment of the overdue interest on the first loan. Is that withholding prepaid interest on the second loan, or repayment of the first claim?
Suppose the first loan is 10 million won with 1 million won of unpaid interest, and the lender advances a second loan of 10 million won for six months, withholding 1 million won and handing over 9 million won. The ceiling in force at the date of the agreement is 20 percent per year.
| Characterization | Principal of the second loan | Unpaid interest on the first loan |
|---|---|---|
| Treated as prepaid interest on the second loan | Lawful interest is 900,000 won (9,000,000 × 20% × 6/12), so 100,000 won is excess → 9,900,000 won | 1,000,000 won still outstanding |
| Treated as repayment of the first claim | 10,000,000 won in full | Extinguished |
Measured against total indebtedness, 900,000 won turns on the characterization. The shorter the term of the second loan, the smaller the lawful interest and the larger the excess, so the gap widens. The money and the transaction are identical; only the label differs.
It should be noted that no decision of the Supreme Court of Korea squarely addressing this question has been identified. The 2021 decision discussed above (2020Da289989) does not resolve it either. There the lower court had already found the amount to be prepaid interest deducted in advance, and only the subsequent method of calculation was at issue.
How is the character of that deduction determined?
Absent a decision on point, the test must be drawn from adjacent authority. The closest language appears in the decision of February 23, 2023 (2022Da286144), where the borrowers argued that the amounts withheld were investment-related costs and commissions rather than interest.
The Supreme Court held that once the advance deduction is found to have been made pursuant to an interest agreement, it constitutes a deduction of prepaid interest, so that where the deduction exceeds the amount calculated at the statutory ceiling on the sum the borrowers actually received, the excess is deemed applied against principal.
The dividing line is therefore whether the withholding was made pursuant to an interest agreement relating to the second loan. The factors below are drawn from the authorities discussed here as practical guidance; they are analysis, not a test articulated by the Court.
| Points toward prepaid interest | Points toward repayment of the first claim |
|---|---|
| The amount corresponds arithmetically to the term and rate of the second loan | The amount matches the overdue interest on the first loan exactly |
| The second loan agreement contains an interest clause and the deduction implements it | There is a designation or agreement on application of payment, and a receipt entry against the first claim |
| Interest on the first claim exceeded the ceiling and so did not lawfully exist | Interest on the first claim was within the ceiling and its discharge is reflected in the records |
| No funds actually moved; the second loan was a formality | The second loan was genuinely disbursed as separate funds |
The last row connects to a separate line of authority. The Supreme Court has held that a so-called rollover, in which a new loan is extended only in form, without any actual movement of funds, in order to repay an existing debt, is in substance no more than an extension of the maturity of the existing obligation, and is legally characterized as a quasi-loan for consumption under which the existing debt continues to exist with its identity preserved (Supreme Court of Korea, February 23, 2012, 2011Da76426). If a transaction that looks like a new loan is in truth a deferral, no separate principal arises in the first place.
Can excess interest be revived by rewriting the promissory note?
It cannot, and this point is often overlooked. Even where the withheld amount is genuinely characterized as repayment of the first claim, the analysis is not finished. Whether that interest was lawful in the first place must be examined.
Under Article 2(3) of the Interest Limitation Act the portion of an interest agreement above the ceiling is void, and under Article 2(4) any excess interest the debtor pays voluntarily is applied against principal. The interest available to be discharged may never have existed in that amount.
Rolling the excess into a new promissory note or a quasi-loan for consumption changes nothing. The Supreme Court has held that where a debtor voluntarily pays interest exceeding the maximum rate, the excess is applied against principal, and that even if the parties conclude a quasi-loan for consumption or a novation covering that excess, it has no effect as to that amount (Supreme Court of Korea, January 15, 2015, 2014Da223506).
In practice it is common for overdue interest to be folded into principal each time a new note is signed. The portion above the ceiling does not revive on new paper. A lender may therefore overestimate what is recoverable, and a borrower may have grounds to dispute the balance.
Why does this calculation matter in fraudulent transfer litigation?
Return to the fact that the 2021 decision was a fraudulent transfer case. When a creditor seeks to set aside a debtor’s disposition of assets, the scope of avoidance and of value restitution is limited by the amount of the secured claim. If that amount is inflated, the scope of avoidance is inflated with it.
In that case the plaintiff’s claim was a loan receivable assigned from a third party, and the loan had been disbursed net of prepaid interest. If the prepaid interest calculation changes, the principal changes; if the principal changes, so does the amount of the secured claim; and the sum the transferee must return changes accordingly. An error of law in the method of calculation alters the outcome of the case.
A violation of the principle of party presentation compounded the problem, because the court had itself found a loan total that no party had asserted and used it as the basis for its ruling. The Supreme Court identified both errors and remanded without reaching the remaining grounds of appeal.
A transferee defending a fraudulent transfer action in South Korea should therefore not confine the defense to whether the secured claim exists. Whether the amount was calculated correctly under the Interest Limitation Act deserves separate examination. Where prepaid interest, charges withheld under another label, or promissory notes rewritten to include overdue interest are present, the claim amount itself may be reduced.
Frequently Asked Questions
Q. I agreed to borrow 100 million won and received 90 million won after a deduction of 10 million won. What is my principal?
A. It is not the 90 million won you received. Lawful interest for the period is first computed on the 90 million won at the ceiling in force when the loan was agreed, and if the 10 million won deducted exceeds that figure, the excess is subtracted from the face principal of 100 million won. Applying a ceiling of 30 percent per year over one month, the Supreme Court of Korea calculated lawful interest of 2.25 million won and applied the excess of 7.75 million won against the 100 million won, leaving a principal of 92.25 million won (October 11, 2012, 2012Da55198).
Q. Why can the excess not be subtracted from the amount actually received?
A. Because the same deduction would be counted twice. The net amount received has already been reduced by the prepaid interest, so subtracting the excess from it again double counts. Under Article 3 of the Interest Limitation Act the net amount is only the base for computing lawful interest, while the amount reduced is the agreed principal before the deduction. The Supreme Court of Korea stated on November 16, 2023 (2023Da266390) that the excess is applied against the loan principal agreed between the parties before the deduction of prepaid interest.
Q. What is the ceiling for a contract concluded today?
A. Twenty percent per year. Presidential Decree No. 31593, amended on April 6, 2021 and effective July 7, 2021, sets the maximum contractual interest rate for monetary loans at 20 percent per year. Article 2(2) of the Interest Limitation Act defines the maximum rate as the rate in force at the time of the agreement, so earlier contracts are governed by the ceilings of 30, 25, or 24 percent that applied when they were made. Because each amending decree applies to contracts concluded or renewed after its effective date, any renewal must also be checked.
Q. Can the ceiling be avoided by describing the charge as a fee rather than interest?
A. No. Article 4(1) of the Interest Limitation Act deems anything a creditor receives in connection with a monetary loan to be interest regardless of its label, including gratuities, discounts, commissions, deductions, and advance payments. The Supreme Court of Korea held that an amount deducted as an introduction fee is deemed interest where it can be regarded as consideration for the loan, so that deducting it in advance is a deduction of prepaid interest (September 30, 1997, 97Da24023), and reached the same conclusion for brokerage commissions and notarization fees (November 13, 2014, 2014Da24785, 24792, 24808).
Q. Does that mean everything the lender receives is interest?
A. Not quite. The test is whether the amount is consideration for the loan. In its en banc decision of September 18, 2025 (2023Da221885), the Supreme Court of Korea held that a prepayment fee is liquidated damages for the borrower’s early repayment and therefore cannot readily be regarded as consideration for the loan, so it is not deemed interest under Article 4(1). The inquiry looks past the label to the substance, and within substance to whether the amount is consideration for the credit.
Q. Is there a Supreme Court decision on deducting unpaid interest of an earlier loan from a second loan?
A. None has been identified. No decision of the Supreme Court of Korea addressing that structure as a stated holding was found. The decision of March 25, 2021 (2020Da289989) does not resolve it either, because the lower court had already found the amount to be prepaid interest deducted in advance and only the subsequent method of calculation was challenged. The question must therefore be analyzed through Article 4 on deemed interest and the criteria for characterizing a deduction as prepaid interest.
Q. How is it determined whether the deduction is prepaid interest or repayment of the earlier loan?
A. The criterion is whether the advance deduction was made pursuant to an interest agreement relating to the second loan. The Supreme Court of Korea held that once an advance deduction is found to have been made pursuant to an interest agreement, it constitutes a deduction of prepaid interest (February 23, 2023, 2022Da286144). In practice the analysis also considers whether the amount corresponds to the term and rate of the second loan, whether it matches the overdue interest on the first loan, whether any designation or receipt of application of payment exists, and whether funds actually moved.
Q. We folded overdue interest into principal and signed a new promissory note. Is the full amount recoverable?
A. Not the portion above the ceiling. The Supreme Court of Korea held that excess interest paid voluntarily is applied against principal, and that even if the parties conclude a quasi-loan for consumption or a novation covering that excess, it has no effect as to that amount (January 15, 2015, 2014Da223506). Re-executing the documents does not revive what the statute has voided.
Q. What can a transferee dispute in a fraudulent transfer action?
A. Not only whether the secured claim exists, but whether its amount was calculated correctly under the Interest Limitation Act. The scope of avoidance and value restitution is limited by the amount of the secured claim, so a reduction in that amount reduces the restitution. In its decision of March 25, 2021 (2020Da289989), the Supreme Court of Korea reversed a lower court that had treated prepaid interest as a repayment received on the day of disbursement, and also identified a violation of the principle of party presentation where the court found a loan total no party had asserted.
This article summarizes the calculation of prepaid interest and its application against principal under the Interest Limitation Act of South Korea, based on published decisions of the Supreme Court of Korea. It is not legal advice on any particular matter. The character of a deduction and the applicable ceiling depend on the date of the agreement, the wording of the contract, and the actual movement of funds, so specific situations require separate examination.
