A Canadian Sells US Stocks: Who Taxes the Gain? Canada Does — the US Almost Never

The question feels like it should be complicated — American company, American exchange, maybe an American brokerage — and the answer is one of the cleanest in cross-border tax: a nonresident alien's gains from selling US stocks, ETFs, and bonds are not US-source income subject to US tax. No withholding comes off the sale (the W-8BEN on file confirms status; nothing else happens), no 1042-S issues for the proceeds, no 1040-NR is triggered by trading, and the gain belongs entirely to Canada: reported on the T1 as a capital gain in Canadian dollars — purchase and sale each converted at their own dates, so currency movement is part of the Canadian gain — half-included at marginal rates. The contrast with dividends is the point of frequent confusion: the same stock's dividends withhold at 15% because dividends are FDAP income the treaty and statute reach; its sale gains are simply outside the US net for a nonresident. The edges, for completeness. US real property holding corporations: FIRPTA extends to shares of US corporations whose assets are predominantly US real estate — but regularly-traded stock is carved out for holders of 5% or less, which exempts every ordinary portfolio position in listed REITs and real-estate-heavy names; the exposure is private or concentrated real-estate-company stakes. The 183-day rule for nonresidents: a nonresident individual present in the US 183 days or more in the year can be taxed at 30% on US-source capital gains — a rule that in practice pairs with having become a resident under substantial presence anyway, and one more consequence of the over-183 winter covered elsewhere. Effectively connected gains: securities held in connection with a US business (a US branch, a dealer operation) are taxed as business income — not a portfolio investor's fact pattern. And at death rather than sale, the analysis flips entirely: those same US-listed shares are US-situs assets for estate tax purposes — the estate-side exposure that makes holding structure matter even though lifetime sales are free of US tax.

Key takeaways

• The rule: portfolio capital gains of a Canadian resident on US securities — stocks, ETFs, bonds, options — are not taxed by the US. No withholding on proceeds, no US return from trading activity.
• Canada taxes the gain fully: CAD-measured (FX is gain or loss), half-inclusion, superficial-loss and identical-property averaging rules apply — the Canadian ledger, not the broker's USD gain report, is the tax record.
• Dividends ≠ gains: the 15% treaty withholding on dividends coexists with 0% on sale gains from the same share — two different income types, two different regimes.
• Edge 1, FIRPTA companies: shares of US real property holding corporations are FIRPTA property — but the regularly-traded 5%-or-less exception covers normal listed positions, including REIT ETFs; private US real-estate entities are where the exposure lives.
• Edge 2, the 183-day nonresident gains rule: present 183+ days in the year, and US-source gains can face 30% — academic for the compliant snowbird (who is either under the line or dealing with residency itself), real for the overstayer.
• The estate-tax asymmetry: no US tax on selling in life; US-situs inclusion at death. Large direct US-stock positions are a lifetime non-issue and an estate-planning line item — the sequencing behind the fund-structure planning in the estate exposure discussion.

The practical consequences

Rebalancing, harvesting, and trading US positions from Canada needs no US calendar: the discipline is entirely Canadian — ACB tracking in CAD, settlement-date conventions, the superficial-loss window around repurchases. The one US-flavored habit worth keeping is documentary: the W-8BEN current at the broker (so the dividend side withholds correctly and status is never in question) and the awareness that the same shares carry estate-side situs — so a portfolio built for decades of holding gets its US exposure structured (Canadian-fund wrappers where estate size warrants) even though every sale along the way is US-tax-free.

Worked example

A Victoria investor sells US$250,000 of Apple and a US-listed S&P ETF from her Canadian brokerage in 2026, positions bought in 2019 for US$140,000. US side: nothing — no withholding on the proceeds, no form, no filing; her W-8-equivalent certification at the Canadian broker simply keeps the dividend machinery correct. Canadian side: purchase converted at 2019 rates (about C$185,000), sale at 2026 rates (about C$338,000) — a C$153,000 gain, larger than the USD gain because the US dollar strengthened; C$76,500 taxable at her BC rates. Her cousin's contrasting file: a 12% stake in a private Arizona land-development corporation sold the same year — a US real property holding corporation with no regularly-traded exception — so FIRPTA withholding applied at closing and a 1040-NR settled the US tax, with Canada taxing the same gain and crediting the US side. Same year, both sold American assets: the listed portfolio never touched the US system; the private real-estate stake was in it from the first closing document.

Official sources

"FDAP income is taxed at a flat 30 percent (or lower treaty rate, if qualify) and no deductions are allowed against such income. ... Effectively Connected Income, after allowable deductions, is taxed at graduated rates." — Internal Revenue Service, Taxation of Nonresident Aliens, https://www.irs.gov/individuals/international-taxpayers/taxation-of-nonresident-aliens

The CRA explains how to calculate and report capital gains and losses, including the inclusion rate and the treatment of net capital losses. — Canada Revenue Agency, Capital gains, https://www.canada.ca/en/revenue-agency/services/tax/individuals/topics/about-your-tax-return/tax-return/completing-a-tax-return/personal-income/line-12700-capital-gains.html

Practitioner note

This is the answer clients disbelieve until it's shown twice: the US taxes a Canadian's American dividends and ignores their American gains, and the entire compliance burden of a US portfolio sale is a Canadian one — the CAD ledger where currency quietly rewrites the gain. The edges we actually screen for are private real-estate entities and the estate-side situs of large direct positions; everything else is a T1 exercise.

See also: Browse every cross-border tax topic guide, organized by situation.

Next step

Fairlight prepares the US portfolio review — the gains/dividends regime map, CAD ledger and FX gain computation, FIRPTA screening for real-estate entities, and the estate-situs structuring for large positions. See cross-border pricing or book a call.