ISA Account — Is Korea's 'Tax-Free Account' Really Tax-Free?

The ISA (Individual Savings Account, Korea's 개인종합자산관리계좌) is a Korean government-designed account offering tax advantages to encourage saving and investing. Ads often describe it as a "tax-free account," but what does the actual tax benefit look like? This article breaks down ISA's real value for a salaried worker using official sources and concrete numbers.

This article is for informational purposes and is not tax advice. Rates, limits, and requirements can change, so verify the latest tax law and your own tax position with a tax advisor or financial professional, and against the Financial Services Commission's ISA guidance and National Tax Service materials, before opening an account.

ISA Tax Benefits — Two Core Rules

• Tax-free threshold: 2M KRW for general accounts, 4M KRW for lower-income workers (total salary ≤ 50M KRW / comprehensive income ≤ 38M KRW). All net gains from interest, dividends, and capital gains within this limit are completely tax-free (Financial Services Commission ISA policy Q&A).
• 9.9% separate taxation on amounts above the threshold: Instead of the standard 15.4% withholding tax, only 9.9% (including local income tax) applies to net gains above the tax-free limit. These gains are also excluded from comprehensive income, so they don't push up your progressive tax bracket — because this is separate taxation under the Restriction of Special Taxation Act (Restriction of Special Taxation Act Article 91-18, Korea Law Information Center).

There's one point people frequently miss: ISA's tax-free allowance and 9.9% rate apply only after netting your gains and losses inside the account (손익통산, loss-and-gain offsetting). According to the Financial Services Commission, ISA taxes the net profit — gains across all products in the account minus losses (FSC). In a regular account, even if you make 1M KRW on stock A and lose 600K KRW on stock B, the 15.4% on interest and dividends is withheld regardless of your losses. Inside an ISA, however, tax is assessed on net profit only (1M − 600K = 400K KRW). Loss offsetting is as powerful a tool as the tax-free allowance itself — yet it's rarely mentioned in the ads.

General vs. Lower-Income ISA — Which One Is Yours?

The ISA's tax-free limit can differ by up to 2x depending on your eligibility. Confirm which type you qualify for before you open the account.

Lower-income eligibility is judged once, against the income of the tax year before you open the account, and the 4M KRW tax-free benefit holds until maturity even if your salary rises later. If you're a recent hire earning around 50M KRW, it pays to open the lower-income type before your salary climbs higher. The limits and rates above are the current rules in effect as of June 2026 (FSC). Through 2026 there's ongoing discussion of raising the limits ("Super ISA," National Growth ISA, etc.) — to separate what's confirmed from what's merely proposed, read 2026 ISA Reform — Should You Wait? alongside this article.

Regular Account vs. ISA — Same Return, Different Result

Scenario: 300K KRW/month for 5 years, 6% annual return.

• Total principal: 18M KRW
• Value after 5 years (compound): ~21.07M KRW
• Total gain: ~3.07M KRW

Regular account (15.4% interest/dividend tax): 3.07M × 15.4% = ~470K KRW in taxes → ~2.6M KRW net gain

ISA general account (2M free + 9.9%):

• First 2M KRW: 0 tax
• Remaining 1.07M × 9.9% = ~106K KRW in taxes
• Total tax: ~106K KRW → ~2.96M KRW net gain

With the same 5-year timeline and return rate, ISA leaves you roughly 360K KRW more. That's about 78% less tax paid compared to a regular account. The advantage scales proportionally as the amounts grow.

Tax Savings by Gain Size — At a Glance

The table below shows how ISA's tax advantage widens as gains grow, using the general type (2M KRW tax-free). "Tax" is the amount levied on that gain; "Savings" is what you keep versus a regular account (15.4%).

As the table shows, gains up to 2M KRW are fully tax-free, so the savings are most dramatic there; above that, savings accumulate at the 5.5-percentage-point gap between 9.9% and 15.4%. With the lower-income type, the fully-tax-free band extends to 4M KRW, so savings reach 616K KRW at a 4M KRW gain.

One more thing. The table above compares income that a regular account taxes at 15.4%, such as interest and dividends. If you instead run overseas stocks like U.S. ETFs directly, the tax structure is entirely different — they're taxed as capital gains at 22% (with a 2.5M KRW basic deduction). To understand the gap between the two worlds precisely, read How to Calculate U.S. ETF Capital Gains Tax alongside this article.

ISA Gotchas — A "Common Mistakes" Checklist

ISA is not an account where putting money in is always a win. If any of these apply to you, check carefully before opening one.

• ☐ 3-year mandatory holding period: To keep ISA's tax-free and 9.9% benefits, you must hold the account for a set period. Income-earning youth and lower-income holders get a 3-year minimum, while the base holding period can be longer — check your account terms for your own maturity condition. Close before maturity and the tax you'd received at the tax-free/9.9% rate is reclaimed at the regular 15.4%. Never put money in ISA that you might need urgently (FSC).
• ☐ Tax-free applies to net profit: It applies not to unrealized gains but to the loss-offset result fixed at maturity (or closure). If you don't clear out losing positions just before maturity, you can waste your tax-free allowance.
• ☐ Unused contribution room does NOT carry over: Contrary to a common misconception, room you don't use in a given year (against the 20M KRW annual cap) does not roll over to the next year (FSC). Contributing only 10M KRW one year does not let you contribute 30M KRW the next. To maximize the cap, fill 20M KRW steadily each year.
• ☐ No direct overseas ETF purchases: You can't buy U.S. stocks or U.S.-listed ETFs directly inside ISA. You must work around it with Korean-listed U.S. ETFs (TIGER, KODEX, ACE).
• ☐ No duplicate accounts: One account per person across all financial institutions. If you already have an ISA and want a new one, you must close the existing one first.
• ☐ Account-type choice: Brokerage-type (중개형) lets you trade ETFs most freely. Trust-type is run through banks; discretionary-type is managed by an asset manager. If you'll trade ETFs yourself, brokerage-type is the answer.

The most common mistake is the first one. People hear "just lock it up for 3 years to save tax" and park even their emergency fund in it — then, if a sudden need for cash forces them to close before maturity, the benefit becomes zero and only transaction costs remain.

Transferring to IRP After Maturity — The Real Tax Magic, but Mind the "60 Days"

After the ISA matures, transferring funds to a pension account (IRP or pension savings) unlocks an additional benefit. Under Restriction of Special Taxation Act Article 91-18, if you pay the funds into a pension account within 60 days of maturity, 10% of the transferred amount (up to 3M KRW) is added to your pension-account tax deduction limit (Restriction of Special Taxation Act Art. 91-18).

• This 3M KRW is added on top of your existing pension savings/IRP deduction limit (9M KRW/year), separately. That year you can have up to 12M KRW eligible for the deduction.
• Example: Transfer 30M KRW of matured ISA funds into an IRP within 60 days → 30M × 10% = 3M KRW extra deduction limit → if total salary ≤ 55M KRW, 3M × 16.5% = ~495K KRW extra refund; above 55M KRW, 13.2% = ~396K KRW.
• The trap: Miss the 60 days by even one day and it's treated as an ordinary deposit, so the extra deduction is gone. A plain bank transfer doesn't count either — you must use your provider's "pension transfer (rollover) service."
• Note: IRP and pension savings funds are locked until age 55, so this strategy is best suited for retirement savings.

This "ISA → pension account transfer" is a separate tax break layered on top of ISA's own tax-free allowance and 9.9% rate. If pension-account tax deductions are new to you, it's worth first sorting out which account to fund and how much to maximize your refund in Pension Savings vs. IRP — Tax Deduction Priority for Korean Workers.

Who Should Use ISA?

• ✅ Salaried workers who can lock up funds for 3+ years
• ✅ Higher-income earners in progressive tax brackets (separate taxation saves money)
• ✅ People in their 30s–50s wanting both retirement planning and tax savings
• ✅ Investors with a large allocation to dividend stocks/ETFs (dividend income gets the tax-free/9.9% treatment, helping manage the 2,000만 KRW financial-income comprehensive taxation threshold)
• ❌ Recent graduates expecting major spending soon (marriage, moving, etc.) — the 3-year lock is a real constraint
• ❌ Investors whose core strategy requires buying U.S. stocks directly

Quick Start Guide

1. Open a "중개형 ISA" (brokerage-type ISA) on any securities app — takes about 5 minutes
2. Check whether you meet the lower-income criteria (total salary ≤ 50M KRW, etc.) — if so, your tax-free limit is 4M KRW
3. Set up a monthly automatic transfer (as low as 100K KRW/month)
4. Buy Korean-listed ETFs (TIGER S&P500, KODEX 200, ACE NASDAQ100, etc.)
5. At maturity, consider transferring to an IRP/pension savings within 60 days of the maturity date → extra tax deduction

Calculate Your Own Tax Savings

Want to compare a regular account vs. ISA using your own contribution amount, period, and return rate? The dedicated ISA calculator instantly shows your savings with the tax-free limit and 9.9% separate taxation already built in.

Open the ISA Tax Savings Calculator →

If you plan to run a dividend-heavy portfolio, it also helps to simulate per-holding dividends and after-tax payouts.

Open the Dividend Simulator →

If you'd rather compare the compounding effect by changing the tax rate yourself, use the compound interest calculator and switch the rate from 15.4% (regular) to 9.9% (ISA above-threshold).

Compare with the Compound Calculator →

Wrap-Up

ISA is less a "tax-free account" than an account that deeply discounts your tax. The essentials: (1) gains up to 2M KRW (general) / 4M KRW (lower-income) are fully tax-free; (2) the excess is taxed at 9.9% separate tax, not 15.4%; (3) tax applies only to net profit after offsetting gains and losses inside the account; (4) transferring to a pension account within 60 days of maturity adds up to 3M KRW of extra tax deduction. Just remember the flip side — close before the 3-year mandatory period and the benefit is clawed back, and unused contribution room does not carry over — and ISA is the first tax-saving account a Korean worker should fill.

References

• Financial Services Commission — Individual Savings Account (ISA) policy Q&A (tax-free limits, 9.9% separate taxation, loss offsetting, annual contribution cap, no carryover of unused room)
• Korea Law Information Center — Restriction of Special Taxation Act Article 91-18 (special taxation for individual savings accounts) (tax-free/separate taxation and the post-maturity pension-account transfer extra deduction)
• National Tax Service — Hometax (filing of separate taxation and pension-account deductions)

This article is for informational purposes and is not tax advice. ISA tax benefits are subject to change based on government policy. Verify the latest tax regulations and your personal tax bracket with a tax advisor or financial professional before opening an account. (Last updated: 2026-06-24)