US Dividend Tax in Korea: 15% Withholding and the 20M Won Line

Dividends from US stocks are taxed 15% at source in the United States, and Korean brokers add nothing on top. Korea's withholding rate on dividend income is 14% before local income tax, so the 15% already collected in the US is the larger of the two and the domestic settlement step simply disappears. On a gross dividend of 1 million won, 850,000 won lands in the account — and unless the year's combined interest and dividend income crosses 20 million won, the tax calculation ends there.

The same logic runs the other way elsewhere. A Korean guide to overseas stock taxation notes that Chinese dividends are withheld at only 10% locally, so Korean brokers collect an additional 4.4% — the 4-point gap plus local income tax.

The 15% comes from a treaty, not a tax rate

Under US law the default withholding rate on dividends paid to non-resident foreigners is 30%. What pulls it down to 15% is the Korea-US tax treaty. Filing Form W-8BEN certifies that the investor is a treaty-country resident rather than a US taxpayer, and Pundit explains that once the 15% is withheld under the treaty, the US tax obligation on that income is settled.

For accounts opened through Korean brokers, the form is normally handled by the broker at account opening. It expires, though, and a missed renewal snaps the rate back to 30%. If a dividend credit shows 30% withheld instead of 15%, the renewal status is the first thing to check.

Some payouts also get reclassified as return of capital (ROC), which adjusts the withheld amount after the fact — so a year-end broker statement may not match what actually hit the account.

Why nothing more is withheld at home

Korean dividend withholding is 14% income tax plus 1.4% local income tax, or 15.4% in total. For foreign dividends, that 15.4% is not re-applied; the 14% income tax portion is compared against what was already paid abroad, and only the shortfall is collected.

Read the column vertically and a common assumption falls apart. Below the 20-million-won threshold, the 15.0% effective burden on US dividends is 0.4 points lighter than the 15.4% on Korean dividends — and 0.6 points heavier than Chinese dividends. The spread has nothing to do with policy preference; it is arithmetic between a treaty ceiling and a domestic rate.

Up to 20 million won, the effective rate is locked at 15%

A bank guide to Korea's financial income aggregate taxation confirms that annual financial income up to 20 million won is taxed separately at the withholding rate, with only the excess folded into global income. For US dividends, that withholding already happened abroad, so nothing is owed and nothing is refunded inside this band.

The last row is the benchmark. Twenty million won of Korean dividends leaves 16.92 million after tax; the same amount from US stocks leaves 17 million. The 80,000-won gap is small, but it points the opposite way from the usual assumption. Korea-listed ETFs holding foreign assets follow a different structure, covered separately in the piece on where Korea-listed foreign ETF tax splits at 8.33 million won.

US dividends are decided by amount, not by rate. Up to 20 million won the effective rate is pinned at 15%; above it, the tax is set by the bracket of your other income, not by the dividend itself.

What the excess actually costs

Article 62 of the Income Tax Act requires computing the tax two ways and applying the larger. One method taxes the first 20 million won at 14% and stacks only the excess onto other income at progressive rates; the other applies 14% to the entire financial income and adds the tax on remaining income. The rule exists so aggregation can never lower the bill.

To put numbers on it, fix the assumptions: 50 million won of non-financial taxable income, deductions and credits excluded, 30 million won of US dividends, local income tax at 10% of income tax. Bracket rates used are 6% up to 14 million won, 15% up to 50 million, and 24% up to 88 million.

The dividends add 5.2 million won of computed tax (11.44 million minus 6.24 million). Of that, the 2.8 million on the first 20 million would have been paid under separate taxation anyway; the genuinely new cost is 1 million won — the 10-point gap between 24% and 14% applied to the 10 million excess. Sitting in the 35% bracket instead would make that 2.1 million.

Do you get the 4.5 million back?

This is where the foreign tax credit enters. A Korean tax advisory states the ceiling as "computed tax × foreign-source income ÷ global income," with any excess carried forward for up to ten years. The credit is capped by the share of your total income that came from abroad, not by what the US actually took.

At 30 million won of dividends, only 4.29 million of the 4.5 million paid abroad is creditable and 210,000 won carries forward. Push the dividend to 50 million and foreign-source income becomes half of global income, lifting the ceiling to 8.12 million — enough to absorb the full 7.5 million. Counterintuitively, a bigger dividend makes the credit room more generous.

The effective rate still climbs from 18.3% to 20.5%, because what grows is not the US withholding but the slice Korea's progressive brackets take. The separate treatment of capital gains is covered in the piece on overseas capital gains tax and the 2.5-million-won deduction.

What to watch

• How close year-end interest plus dividends sits to the 20-million-won line, counting December payouts by actual credit date
• The bracket your non-financial income falls in — 1 million won per 10 million of excess at 24%, 2.1 million at 35%
• Whether dividend credits show 15% withheld; 30% suggests an expired W-8BEN
• The broker's annual foreign dividend and withholding statement, the base document for the credit claim
• The balance and start year of any carried-forward foreign tax credit — the window is ten years
• Notices reclassifying dividends as return of capital, which change both the withheld amount and the filing figure

Sources

• Overseas stocks: know the taxes that differ from domestic stocks
• Income Tax Act Article 62 — special rules for aggregating interest and dividend income
• The foreign tax credit and double taxation on overseas ETF dividends
• Guide to financial income aggregate taxation
• US-source income of non-residents