Owning US S-Corporation or Partnership Interests From Canada: Flow-Through to the IRS, a Corporation or Partnership to the CRA

US flow-through entities are built for US owners, and the Canadian resident who holds one — through a move, an inheritance, a business venture, or a US spouse — inherits a set of mismatches that the entity's US paperwork never mentions. The S corporation first, because of its eligibility trap: an S corporation may not have a nonresident alien shareholder; a Canadian resident who is not a US citizen or green card holder is a nonresident alien, and their ownership terminates the S election — converting the corporation to a C corporation for all shareholders from the date of the disqualifying ownership, with the tax consequences (corporate-level tax, loss of flow-through, potential penalties for the corporation's other owners) falling on everyone. The US citizen or green card holder living in Canada is not a nonresident alien and may hold S corporation stock — but the treaty tie-breaker position that a green card holder in Canada might take to be treated as a nonresident can itself terminate the election, a conflict the green-card guides flag. For the eligible Canadian-resident S shareholder, the US side flows the corporation's income through on Schedule K-1 to their 1040 (they are, by definition, a US person filing a 1040); the Canadian side sees a corporation — Canada does not recognize the S election — so the shareholder is taxed in Canada only when the corporation pays dividends, on the dividend as foreign investment income, with a credit for US withholding (none, for a US person) and a foreign tax credit analysis complicated by the fact that the US tax was paid on the flow-through income in a different year than the Canadian tax on the dividend. The treaty addresses the S corporation mismatch through a competent authority agreement that allows Canadian-resident S shareholders to request that the S corporation's income be treated as FAPI (foreign accrual property income) in Canada in the year earned — aligning Canadian timing with US flow-through and allowing the US tax paid to be recognized — a request made to the Canadian competent authority and worth understanding for any Canadian resident holding S stock, because without it the timing mismatch strands credits. Partnerships and LLCs taxed as partnerships: the US flows the income through on Schedule K-1 to the partner — a Canadian-resident nonresident alien partner files a 1040-NR for their share of US-source effectively connected income (with the partnership withholding on the nonresident partner's share at the applicable rates and the partner claiming credit for it), and a US-person partner reports on their 1040; the Canadian side sees a partnership if the entity is a true partnership or an LP (Canada recognizes partnerships and taxes partners on their share of the partnership's income as computed under Canadian rules, in the year earned — timing aligned with the US, character determined by Canadian rules, US tax creditable against Canadian tax on the same income) — but sees a corporation if the entity is an LLC (the corridor's oldest mismatch: the LLC that the US treats as a partnership is a foreign affiliate to Canada, its income taxed to the Canadian member only when distributed, or currently as FAPI if the LLC's income is passive, with the US tax paid on the flow-through creditable only through the awkward foreign accrual tax mechanics — the LLC's Canadian owner is taxed by the US now and by Canada later on income the two countries characterize differently, and the treaty's hybrid rules can deny reduced withholding on the LLC's distributions). Practical texture: the Canadian resident's share of a US partnership's or LLC's income may include state-source income requiring state returns; the partnership's withholding on foreign partners (under the effectively-connected-income rules) is a credit on the 1040-NR that the Canadian owner must actually claim; capital account and basis tracking differs between the systems (US outside basis, Canadian adjusted cost base) and must be maintained separately; and the sale of the interest is taxed by the US as an effectively-connected disposition for the portion attributable to US trade or business assets (with withholding on the transferee) and by Canada as a disposition of the interest under its own rules. The planning conclusions that follow: a Canadian resident who is a nonresident alien should never be an S corporation shareholder (the election dies); a Canadian resident holding US business interests should prefer an LP or a true partnership to an LLC (Canada aligns timing and character with a partnership and mismatches with an LLC); a US person in Canada holding S stock should investigate the FAPI competent authority request to fix the timing; and inherited or accidental US flow-through interests should be reviewed for restructuring — a conversion of an LLC to an LP, a redemption of the nonresident's S shares before the election is jeopardized — before the mismatch has cost a year of credits.

Key takeaways

• Nonresident aliens can't own S stock: a Canadian resident without US citizenship or a green card who acquires S corporation shares terminates the election for every shareholder — redeem or restructure before the transfer, not after.
• Canada doesn't recognize the S election: eligible Canadian-resident S shareholders are taxed by the US on flow-through and by Canada on dividends when paid — a timing mismatch that strands credits, fixable through the treaty's competent authority agreement treating S income as FAPI in the year earned.
• True partnerships and LPs align: Canada taxes partners currently on their share, timing matched to the US flow-through, US tax creditable — the structure that works for Canadian residents.
• LLCs mismatch again: a partnership to the US, a corporation (foreign affiliate) to Canada — taxed by the US now and by Canada on distribution or as FAPI, with awkward credits and possible treaty-hybrid withholding denial on distributions.
• The mechanics to maintain: partnership withholding on nonresident partners claimed on the 1040-NR, state returns for state-source shares, separate US basis and Canadian ACB ledgers, and effectively-connected disposition treatment on sale.
• Restructure accidental holdings early: LLC-to-LP conversions and pre-transfer S share redemptions are cheap before the mismatch runs; the cost compounds every year it does.

The flow-through review for a Canadian resident

What is the entity for US purposes (S corporation, partnership, LLC taxed as partnership, LLC disregarded)? What is it for Canadian purposes (corporation for any LLC and any S corporation; partnership for true partnerships and LPs)? What is your US status (US person or nonresident alien) — and if nonresident alien, is there S stock anywhere (terminate risk)? Where do the two systems' timing and character diverge, and what credit is stranded? Then: the competent authority request for S stock held by US persons in Canada; the LP conversion for LLC interests where feasible; the withholding and state return mechanics for partnership shares; and the ledgers. The review is a one-hour exercise per entity that has, more than once, discovered an S election that died three years earlier without anyone noticing.

Worked example

A Toronto resident (Canadian citizen, no US status) inherits from her American uncle a 20% interest in a Florida S corporation operating a marina and a 15% interest in a Texas LP holding commercial real estate. The S corporation: her ownership as a nonresident alien terminates the election on the date of inheritance — the corporation's US advisors, alerted, arrange for the estate to redeem her shares for cash before distribution rather than transfer them to her, preserving the election for the other shareholders; she receives cash, taxed in Canada as an inheritance (no Canadian inheritance tax) and in the US within the estate's own return. The LP: Canada sees a partnership — her 15% share of the LP's income is taxed in Canada annually as her own, character determined under Canadian rules; the US flows the same share to her on a K-1, the partnership withholds on her effectively-connected share, she files a 1040-NR and a Texas-free state picture (no state income tax), and claims the withholding; the US tax credits against her Canadian tax on the same income in the same year — the alignment a partnership provides. Her ledger keeps US outside basis and Canadian ACB separately from day one. The counterfactual on the S corporation: had the shares transferred to her, the election would have terminated silently, the corporation would have owed C-corporation tax for the period, and the other shareholders would have discovered it at their next filing — a five-figure problem for the family created by a bequest nobody reviewed for eligibility.

Official sources

To qualify for S corporation status, a corporation must "have only allowable shareholders," which "may be individuals, certain trusts, and estates" and "may not be partnerships, corporations or non-resident alien shareholders." — Internal Revenue Service, S Corporations, https://www.irs.gov/businesses/small-businesses-self-employed/s-corporations

The CRA explains the federal foreign tax credit for tax paid to a foreign country on foreign-source income, claimed on Form T2209. — Canada Revenue Agency, Federal foreign tax credit, https://www.canada.ca/en/revenue-agency/services/tax/individuals/topics/about-your-tax-return/tax-return/completing-a-tax-return/deductions-credits-expenses/line-40500-federal-foreign-tax-credit.html

Practitioner note

US flow-through interests held from Canada divide into the structure that works (true partnerships and LPs — timing and character aligned, credits clean) and the two that don't (S stock, which a nonresident alien kills and a US person mismatches; LLCs, which Canada treats as corporations). Our flow-through review runs entity type in both systems against the owner's status, files the competent authority request where S stock is held by a US person in Canada, and pushes accidental LLC and S interests toward LP conversions and pre-transfer redemptions — the cheap fixes that exist only before the mismatch has cost anyone a year.

See also: For whether to sell the Canadian business before or after you move, see whether to sell the Canadian business before or after you move; and browse every cross-border tax topic guide, organized by situation.

Next step

Fairlight prepares the flow-through review — dual characterization of each entity, S election eligibility protection, the competent authority FAPI request for S stock, partnership withholding and state mechanics, separate basis ledgers, and LP conversion or redemption restructuring. See cross-border pricing or book a call.