Do non-US residents pay tax on US stock gains? The US side and the home side

Two taxes that do not know about each other

The US decides whether it taxes the gain because the shares are American. Your home country decides whether it taxes the gain because you live there. Neither side looks at what the other did. So "the US doesn't tax it" and "you still owe tax on it" are not contradictory; they are answers to different questions.

For most readers who live outside the US and buy shares through an online account, the US side ends in zero. The home side is where the real answer sits.

Why a sale can lose 24% even when no US tax is due

Start with the trap, because it costs the most when it goes wrong. The US has backup withholding, and the IRS page on it lists payments by brokers (the ones reported on Form 1099-B) among the payments it can apply to. The current rate is 24%, and it is taken from the proceeds, not the profit.

Suppose you sell $2,000 of stock that you bought for $1,850. If backup withholding applies, $480 is held back. That is more than three times the $150 you made. You can claim it back, but only through a US tax filing, which is a lot of paperwork for someone who has never set foot in the country.

Form W-8BEN is what prevents this. The IRS instructions say a nonresident alien individual is an exempt foreign person for backup withholding, and the form is how the broker learns that. You do not send it to the IRS; you give it to whoever asks for it, which is the withholding agent.

How long a W-8BEN lasts

The rule is more precise than the "renew it every two years" you will see repeated in forums. A W-8BEN stays in effect from the date you sign it until the last day of the third calendar year after that, unless a change in circumstances makes something on it wrong. Sign in October 2026 and it runs to 31 December 2029. Moving country or getting a new passport number counts as a change; submit a fresh one.

Where the form lives depends on the platform. On Binance, we have not found official documentation of where non-US investors submit it, as noted in the dividends article. Before your first sale, look under the account's tax settings, and if nothing is there, ask support directly whether a foreign-status declaration is on file and still valid.

The 183-day rule, and who it is really for

IRS Publication 519, chapter 4, says gains and losses from selling capital assets are not taxed if you were in the United States for fewer than 183 days during the tax year, and other conditions are met. The tax year is the calendar year.

The main other condition: the gain must not be effectively connected with a US trade or business (ECI). Ordinary investing from abroad normally is not.

If you are present 183 days or more, a separate IRS page applies a flat 30% (or a lower treaty rate) to US-source capital gains, even on trades made while you were away. Look at that page's title, though: it is written for nonresident alien students, scholars and employees of foreign governments. Most people who spend half a year in the US would meet the substantial presence test and become US tax residents instead. The people who can stay that long and remain nonresident are mainly those on F or J visas whose days are excluded from the test.

One version circulating online says you owe US capital gains tax only if the gain is ECI and you stayed 183 days. Those are two separate cases, not two conditions. ECI is taxed at graduated rates; the 183-day case is the flat 30%.

The home side: four places, four different outcomes

These are the only four we checked against official sources. If your country is not here, none of these rows tells you anything about it.

A gain on US shares, by where you are tax resident (official sources checked 2026-10)

The UK row is the one English-speaking readers most often get wrong in the other direction: because the US took nothing and the account shows no tax line, the gain feels tax-free. It is only tax-free if it, together with your other gains for the year, stays inside the allowance.

A worked example, UK resident

Figures are illustrative. Suppose that in the 2026/27 tax year:

• you bought US shares for $1,000 and paid a $1 platform fee;
• you sold them for $1,300 and paid another $1 fee;
• you spent no days in the US and your W-8BEN was valid, so the US withheld nothing.

The gain is $298 before converting to pounds. If that is your only disposal this tax year, it sits well under the £3,000 allowance, so no Capital Gains Tax arises on it. Several sales across the year add up, though, and losses can be set against gains, so the figure that matters is the year's total, not one trade.

Fees change the gain, and on small orders they change it a lot. The full cost breakdown lists every charge, and the order cost calculator works one out from an amount.

What to keep before you sell

• Every purchase: date, number of shares (fractions too), price and fee.
• Every sale: date, shares, proceeds and fee.
• The date you signed your W-8BEN, which is where its validity starts.
• Your entry and exit dates for the US this year. The whole US-side answer rests on a day count, and passport stamps or travel bookings are how you show it.