Financial Income and Health Insurance Premiums

Health insurance premiums are not a "tax" collected by the National Tax Service but a "social insurance premium" collected by the National Health Insurance Service. But since they rise automatically as income or property increases, they feel effectively like a tax and are sometimes called a "quasi-tax."

The important point for investors is that when "financial income" like interest and dividends rises, it's not only tax (dividend income tax 15.4%, etc.) that goes out—health premiums can rise along with it.

In other words, when calculating "after-tax returns," it's not over once you subtract only taxes; you must also consider the change in health premiums to see the money that truly remains in your hands. Especially as assets grow, this part starts to be felt.

When discussing financial income and health premiums, the numbers that come up often are 10 million won and 20 million won. These two have different roles.

① 20 million won a year — the line for "dependent status." A person who was a dependent under a working family member (an employee subscriber) and paid no health premium loses dependent status and switches to a "regional subscriber" if their annual income (pensions, earned, business, interest, dividends, etc. combined) exceeds 20 million won. Then they newly pay their own share of the health premium.

② 10 million won a year — the threshold for "when financial income starts to be reflected" in a regional subscriber's premium calculation. If financial income exceeds 10 million won, that income starts to be reflected in the premium computation.

The numbers are similar and easy to confuse, but it's easier to remember 20 million won as "dependent or not" and 10 million won as "whether financial income is captured in a regional subscriber's premium."

If you lose dependent status and become a regional subscriber, the health premium is calculated by summing "income + property + automobile" points.

Income includes financial income, and property includes housing, land, buildings, etc. (property is reflected after subtracting a basic deduction of 100 million won). An automobile isn't scored in points if its residual value is under 40 million won. The points that come out are multiplied by a set amount (about 208.4 won per point as of 2026) to determine the monthly premium.

Even employee subscribers can't relax. If income outside your salary (financial income, etc.) exceeds 20 million won a year, a separate "income-based monthly premium" attaches to that excess.

The key is that a strategy of growing dividends and interest can create another cost—health premiums—beyond tax. Knowing this and designing around it is very different from getting hit by it unaware.

Not at all. This article isn't saying "don't receive dividends" or recommending a particular strategy. It's meant to tell you that a hidden cost called health premiums exists.

It's the same reason our site, The Return of Almost Everything, shows fees, taxes, and exchange rates without hiding them. No matter how good the return on the screen, the "real money that's yours" after subtracting taxes and health premiums can be different.

The impact varies enormously by your actual situation (whether you're a dependent, how much other income you have, how much property you have). So if you're at the point where financial income starts to grow, we recommend consulting a tax accountant or the Health Insurance Service in advance. Checking with your own numbers is far better than worrying vaguely.