Korea's Stock Capital Gains Tax — Why Domestic Stocks Are Tax-Free but Overseas Stocks Cost You 22%

Same Activity, Completely Different Tax Bill

Imagine two investors, each earning 5 million won in gains — one from Korean-listed stocks, one from U.S.-listed stocks. Their trading looked similar, and their reasoning for buying looked similar. But at tax time, their situations diverge completely. One of them effectively owes nothing. The other has to log into Korea's National Tax Service portal (Hometax) the following May and file a return. This isn't an oversight or a loophole — it's the direct result of Korean tax law treating gains on domestic and overseas stocks under two fundamentally different frameworks from the outset. This piece walks through why domestic capital gains are effectively tax-free for most retail investors, how the "major shareholder" exception works, and why overseas stocks follow an entirely different set of rules.

Why Domestic Stock Gains Are Mostly Tax-Free

In principle, individual investors owe no capital gains tax on profits from buying and selling Korean-listed shares. Instead, every sale is charged a flat 0.15% securities transaction tax on the sale proceeds, applied regardless of whether the trade produced a profit or a loss. For the vast majority of retail investors, that transaction tax is effectively the only tax connected to domestic stock trading.

This isn't an accident — it's a longstanding policy choice designed to channel household savings into domestic capital markets and to keep tax administration simple by taxing the transaction itself rather than the gain. The most serious attempt to overturn this framework was the Financial Investment Income Tax (금융투자소득세, "geumtu-se"), originally set to take effect in 2023. After being postponed twice, the National Assembly voted at the end of 2024 to repeal it outright rather than delay it further. That said, with the KOSPI pushing into record territory in 2026, some voices in Korean politics have reopened the debate over taxing capital gains directly — a reminder that this tax-free treatment is a current policy position, not a permanent feature of the law.

The Exception: Becoming a "Major Shareholder" Changes Everything

There is one clear exception to this tax-free treatment. Investors who hold more than a set threshold in a given stock — classified as daejoo-ju, or "major shareholders" — owe capital gains tax on profits from that specific stock. Major shareholder status is assessed as of the end of the fiscal year (typically December 31), and either of the following triggers it:

• Owning 1% or more of a KOSPI-listed company's shares outstanding (2% for KOSDAQ-listed companies), or
• Holding shares in a single stock worth 5 billion won (₩5,000,000,000) or more at year-end market value

The ownership-percentage test aggregates holdings across specially related parties — spouse, direct ascendants and descendants — so an investor can trigger major-shareholder status without realizing it, even if their own individual holding looks modest. The value threshold has also been politically contested: the government's 2024 tax reform proposal floated lowering it to 1 billion won, but backed off after market and political pushback, leaving the 5-billion-won threshold in place. Because this figure tends to resurface in budget-season debates almost every year, it's worth checking the current year's threshold before relying on it near a December cutoff.

Once classified as a major shareholder, gains face progressive rates: 20% on a taxable base up to 300 million won, 25% above that (with additional wrinkles, such as a 30% rate for large-company shares held under one year), plus a 10% local surtax layered on top — pushing effective rates to roughly 22%–27.5%. This is why, every December, certain KOSPI and KOSDAQ stocks see a recurring wave of selling from investors trimming their stakes specifically to stay under the major-shareholder threshold before the year-end measurement date.

Overseas Stocks Run on a Completely Different Track — a Flat 22%

Overseas-listed stocks, including U.S. shares, follow an entirely separate tax regime. Regardless of ownership size, capital gains are, in principle, taxable for every investor. The rate is a flat 22% (20% national tax plus 2% local surtax) — there's no ownership-percentage or holding-value test the way there is for domestic stocks.

Two features soften the burden, though. First, all gains and losses realized across every overseas stock and overseas-listed fund sold during the year are netted together before anything else happens. Second, an annual basic deduction of 2.5 million won (₩2,500,000) is subtracted from that net figure, and the 22% rate applies only to what's left. For example, if an investor made 8 million won on one stock and lost 2 million won on another, the net gain is 6 million won; after the 2.5-million-won deduction, tax applies only to the remaining 3.5 million won. Losing positions must be netted in — skipping them means overpaying.

Unlike domestic stocks, overseas stock capital gains are never withheld by the brokerage. The investor is responsible for self-filing a return and paying the tax directly, between May 1 and May 31 of the following year, either through Hometax or via a tax professional. Most brokerages provide an annual realized gain/loss statement to help with this, but the filing obligation itself rests entirely with the investor — a meaningful practical difference from the automatic, no-paperwork treatment of domestic gains.

Why the Asymmetry Exists

This split isn't a design flaw — it reflects two different policy goals layered on top of each other. Tax-free treatment for domestic stocks is essentially industrial policy: a deliberate choice to grow Korea's capital markets and draw household money into them. The tax on overseas stocks, by contrast, simply follows the general capital-gains framework Korea applies to foreign assets. This asymmetry — favoring the domestic market while taxing overseas investing more heavily — is itself one of the factors regularly cited in discussions of the so-called "Korea Discount," the tendency of Korean equities to trade at lower valuations than comparable global peers.

The Trap Investors Miss: Domestically Listed Overseas ETFs Are Taxed Differently

Here's where a lot of investors get tripped up. Two ETFs can both track the S&P 500, yet be taxed completely differently depending on where they're listed. An ETF listed directly on a U.S. exchange (say, an S&P 500 ETF on the NYSE) follows the overseas-stock rules described above — 22%, with the 2.5-million-won deduction. But an ETF listed on a Korean exchange that tracks a U.S. index — a so-called "domestically listed overseas ETF" — has its trading gains classified not as capital gains but as dividend income, automatically withheld at 15.4%.

At first glance, 15.4% looks like the better deal versus 22%. The catch is that this income counts toward comprehensive financial income taxation. True overseas stock capital gains are taxed separately from an investor's other income (schedular taxation) and never count toward that threshold, no matter how large the gain. But gains from a domestically listed overseas ETF are lumped in with interest and dividend income — and if that combined total exceeds 20 million won in a year, it can get pulled into comprehensive taxation at rates up to roughly 49.5%. Two products tracking the same S&P 500, taxed under entirely different logic purely because of where the ETF itself is listed — worth understanding before choosing between them on an after-tax basis.

Key Takeaways

• Gains from Korean-listed stocks are, in principle, tax-free; most retail investors only pay a 0.15% securities transaction tax on each sale.
• The exception is "major shareholder" status — owning 1% (2% for KOSDAQ) of a stock, or holding 5 billion won or more of it at year-end — which triggers a 20%–25% capital gains tax (roughly 22%–27.5% including local surtax).
• Overseas stock gains are taxable for everyone regardless of holding size: gains and losses are netted, a 2.5-million-won annual deduction is applied, and the remainder is taxed at a flat 22%, self-filed by the investor the following May.
• The tax-free domestic treatment and the 22% overseas rate stem from different policy goals, and this asymmetry is itself part of the broader "Korea Discount" conversation.
• Domestically listed ETFs that track overseas indexes are taxed as dividend income (15.4%) and count toward comprehensive financial income taxation — a materially different after-tax outcome than owning the underlying overseas stock directly.
• Thresholds, rates, and the ongoing political debate over capital gains taxation change with each year's tax legislation, so confirm current figures with Korea's National Tax Service or a tax professional before year-end shareholder-status planning or filing.

Frequently Asked Questions

Does that mean Korean investors never pay tax no matter how much they make on domestic stocks?

Essentially yes, unless they're classified as a major shareholder. Every sale still carries a 0.15% securities transaction tax, but the profit itself isn't taxed. The exception is triggered only when year-end ownership in a specific stock crosses the percentage or value threshold described above — and only that stock's gains become taxable.

Is the 2.5-million-won overseas stock deduction applied per stock?

No. Every overseas stock and overseas-listed fund position sold during the year is netted together first, and the 2.5-million-won deduction is applied once to that combined net figure — not separately to each holding. A loss on one position must be netted against gains on others to calculate the correct taxable amount.

Does a broker automatically withhold overseas stock capital gains tax the way it does for dividends?

No. Unlike dividend withholding, brokerages do not withhold anything from overseas stock trading gains. The investor must self-file a return through Hometax and pay the tax directly the following May; missing the deadline can trigger penalty surcharges.

⚠️ This article is for informational purposes only and is not investment or tax advice. Major-shareholder thresholds, tax rates, and deduction limits can change with each year's tax legislation — confirm current figures through Korea's National Tax Service (Hometax) or a qualified tax professional before making year-end decisions or filing.