Korea's 2026 Market Crash: Tax Rules for Selling at a Loss

Two investors sell 10 million won worth of stock at a loss on the same day, and the tax outcome depends entirely on what each of them sold: the loss on Korean shares gets its owner nothing back, while the loss on overseas shares can erase up to 2.2 million won in taxes. On July 28, the KOSPI closed at 6,023.66, down 732.09 points (10.84%), and the year's eighth circuit breaker — a mechanism that halts trading when prices move violently — was triggered. If you locked in losses that day, this difference should shape what you do between now and December.

Selling Korean Stocks at a Loss: Nothing Happens, Tax-Wise

Start with the bad news. If what you sold in this crash was Korean listed stock, that loss simply doesn't exist for tax purposes.

Under Korea's National Tax Service guidance, minority shareholders who sell KOSPI or KOSDAQ shares on the exchange are not subject to capital gains tax. Gains go untaxed, and losses are never deductible. It's the flip side of the exemption.

Capital gains tax on Korean stocks applies elsewhere: to major shareholders — those holding 5 billion won or more per stock by market value, or crossing ownership thresholds (1% for KOSPI, 2% for KOSDAQ, 4% for KONEX) — and to off-exchange trades and unlisted shares. The market-value threshold was raised from 1 billion to 5 billion won for sales made on or after January 1, 2024. Most retail investors fall well outside these lines.

One cost does apply regardless. Since 2025, the securities transaction tax runs 0.15% on KOSDAQ, while KOSPI trades carry a 0% transaction tax plus a 0.15% rural development tax — effectively 0.15% either way. It's charged on the sale amount whether you made or lost money. On a 10 million won sale, that's 15,000 won on top of your loss.

So for Korean stocks, the decision to cut a losing position is purely an investment call. Taxes only start to matter with overseas stocks, the subject of the next section.

Overseas Stock Losses Are a Tax Asset

Overseas stocks live in a different world. Every investor's gains are taxable at 22% — 20% capital gains tax plus a 2% local income tax — regardless of holding size. In return, there's a basic deduction of 2.5 million won per year.

The formula looks like this.

Tax = (annual gains − annual losses − 2.5 million won) × 22%

The "annual losses" term is where this crash comes in. When you realize a loss, it is subtracted from the same year's gains before tax is calculated. This is loss offsetting — netting gains and losses within one tax year so only the net income is taxed.

Run the numbers. Say you sold US stock A earlier this year for an 8 million won gain, then cut stock B in this downturn at a 5 million won loss. Your tax: (8M − 5M − 2.5M) × 22% = 110,000 won. Had you held B into next year instead, you'd owe (8M − 2.5M) × 22% = 1,210,000 won. The same loss, realized this year rather than next, cuts your bill by 1.1 million won.

The loss itself still hurts. But once the damage is done, whether it counts against your taxes is a separate question — and for overseas stocks, realizing a loss is itself a tax-saving move.

The Three Rules of Loss Offsetting

Offsetting comes with rules. Miss them and the math falls apart.

First, offsetting works only within the same tax year — January 1 through December 31. Last year's losses can't reduce this year's gains, and this year's losses can't carry into next year. More on this in the next section.

Second, only taxable stocks offset each other. Since 2020, Korean and overseas stock gains and losses can be netted — but "Korean stocks" here means only those subject to capital gains tax: major-shareholder holdings, off-exchange trades, unlisted shares. A minority shareholder's on-exchange loss sits outside the tax system entirely, so it can never offset overseas gains. The hope that "my Korean losses will cut my US stock tax bill" collapses right here.

Third, the transfer date is the settlement date, not the trade date. Article 98 of the Income Tax Act sets the transfer date as the day payment is settled. US stocks typically settle one day after the trade, so a sell order executed in late December can settle in January — pushing the loss into next year. In July there's plenty of room, but if you plan year-end trades for offsetting purposes, work backward from the settlement date.

This Year's Losses Die This Year — No Carryforward

This is the most commonly misunderstood part of Korea's stock capital gains tax. Business losses can carry forward to future years, but stock capital losses cannot — there is no carryforward (using this year's unused losses against next year's gains). Both the National Tax Service's interpretation and tax-industry reporting agree on this point. First-half and second-half results net within the same year, but once the year ends, the loss is gone for good.

That principle is where the strategy comes from. Compare two scenarios.

Say an investor has just locked in a 10 million won loss on overseas stocks in this crash, with no realized gains so far this year. Let the year end like this, and that loss is worth nothing in tax terms. But if they realize 7 million won of gains before year-end from positions still in profit, the offset still leaves a net loss — tax stays at zero. Gains that would otherwise have cost (7M − 2.5M) × 22% = 990,000 won get locked in tax-free.

If a portfolio cleanup was on the agenda anyway, a big-loss year is the time. Aligning profit-taking and rebalancing (adjusting asset weights) with a loss year changes the tax bill by hundreds of thousands of won.

Buying back the same stock after selling isn't restricted either. US tax law has a wash sale rule that disallows the loss if you rebuy a substantially identical security within 30 days before or after the sale — Korea's Income Tax Act has no such repurchase restriction for stock capital gains. The price risk between selling and rebuying, though, is entirely yours.

The Spousal Gift Strategy Stopped Working in 2025

For years, investors sitting on large overseas-stock gains leaned on a well-known move. Gift stock to a spouse — tax-free up to 600 million won over ten years under the spousal gift deduction — and the spouse's cost basis steps up to the market price at the time of the gift. If the spouse sold right away, the taxable gain was close to zero.

That door is closed. For stock gifted on or after January 1, 2025, carryover taxation applies: if the recipient sells within a short window, the gain is computed from the donor's original cost, not the stepped-up value. The rule previously covered real estate, pre-sale housing rights (bunyangkwon), and club memberships; it now extends to stock, with a one-year window from the gift date. To get the step-up, the spouse has to hold for a year — and nobody knows where the price will be by then.

With one tool gone, the remaining ones — loss offsetting and the yearly 2.5 million won deduction — matter more than before.

Filing Calendar: Miss It and Pay 20% More

If you've planned the offset, filing is the last hurdle. In Korea, stock capital-gains filings split into interim returns (filed each half-year) and the final return (filed the following May, netting the whole year). The schedule:

Overseas stocks have no interim filing requirement. Everything you realized this year gets reported at once next May. In January or February, download the capital gains statement from your brokerage and enter it on Hometax (the National Tax Service's online filing portal) — and if you use several brokerages, you must combine all accounts. Leave out one account's losses and your tax bill goes up accordingly: the offset is only completed at the filing stage.

Even in a loss-only year, the final filing obligation remains — Article 110 of the Income Tax Act applies the filing requirement even when there's no tax base or a net loss. There's just no tax to pay, so no penalty accrues, and the same goes for gains of 2.5 million won or less, where the deduction brings the tax to zero.

The real problem is owing tax and not filing. That triggers a 20% non-filing penalty — an extra charge added to the tax due when no return is filed by the deadline. On a 1 million won tax bill, that's another 200,000 won.

Volatility You Can't Control, Taxes You Can

The KOSPI has now seen eight circuit breakers this year. The July 28 sell-side sidecar — a device that briefly halts program trading when futures prices swing sharply — was the thirteenth. With the uncertainty over the semiconductor cycle behind this drop still unresolved, a repeat of this kind of move is hard to rule out.

You can't control prices. But which year you realize losses, when you take profits, and which year you claim the 2.5 million won deduction are entirely your call. Three things are worth doing today: pull up this year's realized overseas gains and losses in your brokerage app, build a combined table if you use multiple brokers, and map your profit-taking plan for the rest of the year against the size of your losses.

Two related reads for a crash like this one: if you trade on margin, see how margin call notices work and when a forced sale can be challenged; if you invest through a tax-free account, see Korea's expanded ISA limits and strategies.