Among subscribers who had their health insurance premiums lowered due to reduced income, some who checked expecting a refund the following year instead received a settlement premium notice. Even with the same adjustment application, whether it results in a refund or an additional charge depends not on the income reduction itself, but on the income finalized the following year — that is, the gap between the income reflected at the time of application and the verified income confirmed by the National Tax Service and other sources.

Why an Additional Charge May Come Instead of a Refund

Even if a freelancer whose work dried up applied for adjustment citing reduced business income, if the income finalized by the National Tax Service the following year turns out higher than the amount reflected at the time of application, the underpaid premiums are charged as a settlement premium. Even if only business income was adjusted, earned income is also combined at settlement.

The National Health Insurance Service explains settlement in its premium adjustment and settlement guidance as the procedure for calculating the difference between premiums already paid and premiums based on verified income. If the verified income is lower than the income reflected at the time of application, part of the premiums already paid may be eligible for refund; if it is higher, additional premiums are charged even if income actually decreased.

Settlement Premiums Cannot Be Readjusted Once Finalized

Settlement premiums are difficult to reverse once finalized. The Service stated that because settlement premiums reconcile already-adjusted premiums against verified income from the National Tax Service and other sources, they cannot be readjusted, unlike regular premiums. This means the amount cannot be changed by applying for adjustment again after receiving the notice.

How to Check and Apply for Refunds

If a refund results from settlement, you can verify your identity through the refund inquiry and application menu on the Service's website or the mobile app 'The Health Insurance,' check the details, and apply by entering your bank account. Inquiry and application are also possible through the customer center or a nearby branch. If you pre-register an account in your own name, future refunds can be paid out without a separate application.

Refunds Must Be Claimed Within 3 Years… Beware of Smishing

Refunds have a deadline. Under Article 91 of the National Health Insurance Act, the right to a refund expires if not exercised for three years from the time it becomes exercisable. Settlement refunds also cannot be recovered if the deadline is missed by delaying the application.

Smishing schemes that send website links via text messages disguised as refund notices continue to recur, so it is safest to check directly through the Service's official website or app.

Dependent Status and Out-of-Pocket Cap Benefits Can Also Be Retroactively Revoked

The repercussions of settlement do not end with the premium difference. If you acquired dependent status or received a reduction after premium adjustment and settlement, or received benefits under the out-of-pocket maximum system, which uses premium levels as a criterion, your status may be retroactively revoked or benefits recovered from the date of acquisition, depending on the settlement results.

The out-of-pocket maximum system sets individual caps based on premium levels, so if the premium standard changes due to settlement, you may have to pay back part of the cap-system refunds already received. This is why it is difficult to judge the final outcome based solely on the amount shown on the refund inquiry screen.

Employee Subscribers Are No Exception… Threshold of 20 Million Won in Non-Wage Income

Employee subscribers are no exception. Even if excluded from non-wage monthly income premium charges after adjustment and settlement, if non-wage income exceeds 20 million won in the settlement results, non-wage monthly income premiums may be retroactively imposed. Being excluded at the adjustment stage does not mean final confirmation.

There are also procedural points easy to miss. To acquire dependent status after premium adjustment and settlement, a separate report is required. An adjustment application alone does not automatically process dependent status.

Five Points for Subscribers Applying for or Considering Adjustment

① How far apart the income reflected at the time of application may be from the income finalized by the National Tax Service the following year, and the fact that even if only business income is adjusted, earned income is also combined at settlement

② Adjustment cancellation is possible only within 90 days of the application date, and cannot be done after a settlement premium has been imposed

③ If a refund results from settlement, the right expires if not claimed within three years

④ Dependent status or out-of-pocket maximum benefits received after adjustment may be retroactively revoked or recovered depending on settlement results

⑤ For employee subscribers, whether non-wage income is near the 20-million-won threshold should also be examined

[This article is policy information based on guidance from the National Health Insurance Service and the National Health Insurance Act; settlement results and refund eligibility vary depending on individual verified income. Detailed criteria and application procedures may change according to the Service's policies. AI provided partial assistance.]