An increase in interest and dividends does not mean that everyone’s health insurance premiums rise in the same way. Employee-insured persons, self-employed insured persons, and dependents are subject to different standards, and even the same ETF returns may produce different results depending on how the gains are classified under tax law.
The following explains the system structure as verified in July 2026. Health insurance premium rates, detailed calculation formulas, tax laws, and dependent eligibility standards may be revised, so before making any actual transaction, retirement, or gift, you should confirm the latest applicable outcome with the National Health Insurance Service and a tax professional.
Three Types of Eligibility to Distinguish First
| Category | Basic premium structure | Key threshold at which financial income has an impact |
|---|---|---|
| Employee-insured person | Monthly remuneration-based premium and monthly income-based premium on certain income other than remuneration | Whether annual income other than remuneration is more than 20 million won |
| Self-employed insured person | Calculated based on income and property | Whether total annual interest and dividend income is more than 10 million won |
| Dependent of an employee-insured person | Pays no separate premium but must satisfy income, property, and support requirements | Comprehensive review of total annual income, business income, property tax assessment base, etc. |
Income for health insurance premium purposes generally includes interest, dividends, business income, employment income, pension income, and other income. However, because the applicable inclusion rates by income type and the treatment of tax-exempt and separately taxed income differ, simply adding up amounts deposited into a bank account may lead to errors.
Employee-Insured Persons: Annual Income Other Than Remuneration Threshold of 20 Million Won
Employee-insured persons pay monthly remuneration-based premiums based on their salary. In addition, if annual income other than remuneration—including interest, dividends, business income, employment income, pension income, and other income—is more than 20 million won, an additional monthly income-based premium may apply.
Basic Calculation Structure
Conceptually, the calculation proceeds as follows.
- Identify annual income other than remuneration by income type.
- Apply the inclusion rates prescribed by law.
- Apply the annual deduction threshold of 20 million won.
- Divide the remaining amount by 12 months.
- Apply the health insurance premium rate for the applicable year.
- Add the long-term care insurance premium based on the calculated health insurance premium.
For example, if all income other than remuneration consists of interest and dividends totaling 30 million won annually, under the general structure, the 10 million won remaining after subtracting 20 million won becomes the starting point for calculating the monthly income-based premium. The exact premium varies depending on the premium rate for the applicable year, the period to which the income is attributed, the type of income, and the results of reconciliation.
Points to Note
- Exceeding the threshold does not mean that an additional premium is charged on the entire 30 million won of income other than remuneration.
- Employment income, pension income, and other types of income may be assessed differently from interest and dividend income during the premium calculation process.
- Premiums are reflected after finalized income data from the National Tax Service is linked to the National Health Insurance Service, so there may be a gap between when income is earned and when the premium is billed.
- Rather than giving up legitimate returns simply because income is close to a threshold, compare after-tax returns after accounting for both taxes and insurance premiums.
Self-Employed Insured Persons: The 10 Million Won Annual Financial Income Threshold
For self-employed insured persons, it is important whether the combined annual interest and dividend income is more than 10 million won. If the total is at most 10 million won, that financial income may be excluded from the calculation of self-employed insurance premiums. However, if it is more than 10 million won, the entire amount of the relevant interest and dividend income—not merely the excess—is included.
| Total annual interest and dividend income | General premium treatment |
|---|---|
| At most 10 million won | Financial income is not included in income for self-employed insurance premiums |
| More than 10 million won | The entire amount of the relevant interest and dividend income is included |
Accordingly, the difference in premium calculations between 10 million won and 10.01 million won may be much larger than the actual difference in income. However, because the final premium must also account for other income and property, the minimum and maximum monthly income amounts, and long-term care insurance premiums, it may not equal the amount obtained by simply multiplying financial income by the premium rate.
Information Self-Employed Insured Persons Should Review
- Interest payment dates and maturity dates for deposits and bonds
- Dividends and distributions from domestic and foreign stocks and funds
- Taxable trading gains from domestically listed foreign-asset ETFs
- Business, employment, pension, and other income
- Property tax assessment bases and jointly owned shares
Unlike in the past, vehicle-based premiums for self-employed insured persons were abolished in February 2024. Materials that continue to describe vehicles as a separate assessment factor for self-employed insurance premiums may not reflect the latest system.
Income Classification Varies by the ETF’s Listing Market
Even when tracking the same foreign index, domestically listed ETFs and overseas-listed ETFs may have their trading gains classified differently under tax law.
| Investment method | General tax classification of trading gains | Impact on health insurance premiums |
|---|---|---|
| Domestically listed foreign equity ETF | Taxable amount treated as dividend income | May be included in financial income |
| ETF listed on an overseas exchange, such as in the United States | Capital gains from foreign stocks | Currently excluded in principle from income used to calculate health insurance premiums |
| Ordinary domestically listed domestic equity ETF | On-exchange trading gains of individual investors are generally tax-exempt | Ordinary trading gains are not included in financial income |
Trading gains from domestically listed foreign-asset ETFs are not always treated in their entirety as dividend income. The taxable amount may be determined using factors such as the increase in the tax-base price and the actual trading gain.
Trading gains from overseas-listed ETFs are classified as capital gains, and the annual basic deduction and other rules are applied after aggregating gains and losses from foreign stocks. The general tax rate, including local income tax, must be reviewed separately. The fact that capital gains are currently excluded from health insurance premium calculations does not mean that they are tax-free.
Regardless of the account in which assets are held, cash dividends and ETF distributions are, in principle, dividend income. This is why it should not be assumed that direct overseas investment never affects health insurance premiums.
Managing Financial Income Through an ISA
An ISA is an account that aggregates gains and losses from multiple financial products held within the account, exempts up to a certain amount from tax, and then applies separate taxation to net profit exceeding that amount. Separately taxed income from an ISA is not included in the aggregate financial income subject to comprehensive taxation in the way that interest and dividends from ordinary accounts are, so an ISA may also be used to manage health insurance premiums.
Assets That May Be Prioritized for an ISA
- Products that generate interest income, such as deposits and bonds
- High-dividend stocks and REITs
- ETFs with large distributions
- Domestically listed foreign-asset ETFs whose trading gains are treated as dividend income
By contrast, domestically listed stocks or domestic equity ETFs whose trading gains are tax-exempt even in ordinary accounts may be a lower priority for ISA capacity. However, dividends, the possibility of aggregating gains and losses, the mandatory holding period, and early withdrawal conditions should also be compared.
ISA Considerations
- ISA enrollment may be restricted if you were subject to comprehensive taxation on financial income at least once during the previous 3 tax periods.
- Tax-exempt limits and contribution limits may vary depending on the account type and future legislative amendments.
- Some products are not permitted in an ISA, and stocks and ETFs listed on overseas exchanges cannot be held directly.
- Transferring ISA maturity proceeds to a pension account may provide additional tax benefits, but the transfer limit and deadline must be confirmed.
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