Suppose a taxpayer has failed to claim a 150,000-won refund that the National Tax Service was set to return for over a year. Until 2024, this money would have remained untouched. Now the situation is different. If the taxpayer owes national taxes, the 150,000 won is automatically used to cover those taxes. Instead of being deposited into a bank account, the assessed tax is reduced by that amount.

Automatic Offset Threshold for Small Refunds Raised from 100,000 to 200,000 Won

This change came about as the monetary threshold for automatic offsets was raised. The National Tax Service raised the ceiling for automatically applying unclaimed national tax refunds—those uncollected for one year—toward national taxes due, from 100,000 won or less to 200,000 won or less. The new standard applies to offsets made on or after January 1, 2025. The aim is to reduce the accumulation of long-standing small refunds on the books and simplify the settlement process.

With the threshold doubled, refunds exceeding 100,000 won but at or below 200,000 won have been newly included in the offset targets. For taxpayers with taxes due, unclaimed refunds in this range are settled through tax deductions rather than cash payments. Conversely, for taxpayers with no national taxes to pay, there is nothing to offset, so the refund remains as is.

Expiration of Unclaimed Refunds... 4.6 Billion Won Transferred to State Coffers, Largest in 7 Years

If left unattended for long, remaining refunds ultimately leave the taxpayer's hands. According to data submitted by the National Tax Service to Representative Kim Sang-hoon of the People Power Party in September, national tax refunds that expired and went into state coffers during 2025 totaled 4.6 billion won. This is the largest figure in seven years of records compiled since 2019, nearly double the 2.4 billion won from a year earlier.

The Framework Act on National Taxes stipulates that the right to receive a refund expires if not exercised for five years from the date the right becomes exercisable.

In summary, unclaimed national tax refunds go through two stages: ▲ after one year, small amounts of 200,000 won or less are automatically offset against taxes due, and ▲ any amount not offset is transferred to state coffers the moment it passes five years.

How to Check Refunds on Hometax and Sontax

Refunds remaining in your name can be verified through identity authentication in the 'Find National Tax Refunds' menu on Hometax or the mobile app Sontax. By registering a refund account and requesting payment, you can receive the money in cash.

Two Things to Watch Going Forward

Two matters remain to be confirmed. First, whether the number and amount of offsets actually processed after 2025—the first year the new threshold applied—will be disclosed. Second, whether the amount transferred to state coffers, which nearly doubled in a single year, shows the same trend in 2026. Only by examining offset records and the scale of state coffer transfers side by side can we determine through which path unclaimed refunds are flowing out.

[Whether an offset applies, refund amounts, and the starting date of the expiration period vary by individual, and the system may change, so please be sure to verify through the National Tax Service's Hometax or your local tax office. This article was written with the assistance of AI.]