Cross-Border Intercompany Loans: Interest Withholding, Thin Capitalization, the 163(j) Limit, and Canada's Section 17

Money moving between related companies across the border is debt or equity in the eyes of two tax systems, and the loan agreement is examined by both. The rate — arm's length: interest between related parties must be at the rate unrelated parties would charge on comparable terms (section 482 in the United States, section 247 transfer pricing in Canada), supported by documentation (the borrower's credit standing, the loan's term and security, comparable rates); a rate too high moves profit to the lender's country and is challenged by the borrower's; a rate too low (or zero) is challenged by the lender's — Canada imputes interest on a loan from a Canadian corporation to a non-resident that is outstanding more than a year at an unreasonable rate (section 17 — interest at the prescribed rate, less any interest actually included; section 17(8) excepts a loan to a corporation that was a controlled foreign affiliate throughout the period, to the extent the money is used to earn income from its active business), and the United States can impute interest under section 482 or the below-market loan rules (section 7872). Withholding on the interest — the treaty's zero: Canada's Part XIII tax on interest paid to non-residents is 25 percent by default but generally doesn't apply to arm's-length interest (domestic exemption since 2008) and — for related-party interest — the treaty reduces it to zero (the fifth protocol's elimination of withholding on interest between related parties, fully phased in from January 1, 2010 — the NR301 guide's interest row); the United States' 30 percent withholding on interest to a foreign person is reduced to zero by the treaty for interest beneficially owned by a Canadian resident (Article XI(1) — subject to the limitation-on-benefits article, the hybrid-entity rules of Article IV(7), and Article XI(6), which lets contingent interest be taxed at up to 15 percent); so most cross-border intercompany interest carries no withholding with the forms in place (the Canadian lender's W-8BEN-E to the U.S. borrower; the U.S. lender's NR301 or NR302 to the Canadian borrower). The borrower's deduction — the caps: the United States limits business interest deductions under section 163(j) to 30 percent of adjusted taxable income (EBITDA-based again for tax years beginning after 2024, P.L. 119-21 having restored the depreciation and amortization add-back) plus business interest income, with small businesses under the gross receipts threshold exempt (the used car dealer guide's floor plan point — the threshold is US$32 million for 2026, measured on the gross receipts of the whole more-than-50-percent controlled group, foreign parent included, so a subsidiary of a larger group rarely qualifies); disallowed interest carries forward; and the U.S. anti-hybrid rules (section 267A) deny deductions for interest paid to a related party in a hybrid arrangement (a payment deductible in the United States and not included in income in Canada — the U.S. LLC's classification mismatch — the Canadian resident owning a U.S. LLC guide). Canada limits deductions through thin capitalization (section 18(4) — interest on debt owed to specified non-residents exceeding a 1.5-to-1 debt-to-equity ratio is non-deductible — equity being retained earnings at the start of the year plus the monthly averages of contributed surplus and paid-up capital attributable to specified non-resident shareholders — and section 214(16) deems the disallowed interest a dividend subject to Part XIII withholding, 5 percent under the treaty for a U.S. corporate parent owning at least 10 percent of the voting stock) and the excessive interest and financing expenses limitation (EIFEL — 30 percent of adjusted taxable income for taxation years beginning on or after January 1, 2024, applied after thin capitalization; excluded entities include Canadian-controlled private corporations whose taxable capital employed in Canada, with associated corporations, is under C$50 million, groups whose net interest and financing expenses total C$1 million or less, and certain mostly domestic groups — a U.S.-owned Canadian subsidiary isn't a CCPC and isn't a domestic group, so the C$1 million test is usually its only way out). The upstream loan — subsidiary to parent: a U.S. subsidiary lending to its Canadian parent can be treated by the United States as an investment in U.S. property by a controlled foreign corporation — not applicable, since the U.S. subsidiary is a domestic corporation; but a Canadian subsidiary (a CFC) lending to its U.S. parent is a section 956 investment in U.S. property, historically taxable to the U.S. parent as a deemed dividend (the regulations now generally reduce the section 956 amount for corporate U.S. shareholders to the extent a dividend would qualify for the section 245A deduction — Treas. Reg. §1.956-1(a)(2), finalized in 2019 — though not for individual shareholders); and Canada's upstream loan rule (section 90(6)) includes in the Canadian parent's income a loan from its foreign affiliate that isn't repaid within two years other than as part of a series of loans and repayments (section 90(8) excepts ordinary-course commercial debts and money-lending business loans with bona fide repayment terms, and section 90(9) allows an offsetting deduction to the extent the affiliate's surplus would have sheltered a dividend) — and a Canadian corporation's loan to its non-resident shareholder (a U.S. owner borrowing from their Canadian company) is a shareholder loan included in the shareholder's income if not repaid within a year after the corporation's year-end, which for a non-resident is a deemed dividend with Part XIII withholding (section 15(2), with the repayment window in section 15(2.6); section 214(3)(a) makes the amount a dividend for Part XIII — 15 percent under the treaty for an individual — refundable under section 227(6.1) if the loan is later repaid). Documentation: the written loan agreement (amount, rate, term, security, repayment schedule), the board resolutions on both sides, the transfer pricing support for the rate, the actual payments made (interest accrued but never paid is a red flag for recharacterization as equity), the withholding forms, and the debt-to-equity and EIFEL computations; debt that behaves like equity (no repayment schedule, subordinated to everything, payable only from profits) can be recharacterized as equity by either country — interest becoming a non-deductible dividend. The bookkeeping: loans by direction, with agreements and rates; interest accrued and paid; withholding forms and NR4s or 1042-Ss where applicable; the 163(j) and EIFEL computations; the thin capitalization ratio; the upstream loan rules' two-year and one-year clocks. The errors: an interest-free loan from a Canadian corporation to a U.S. sister company, or to a U.S. subsidiary not using the money in its active business (section 17 imputed interest in Canada); interest at an unsupported rate; a Canadian subsidiary's thin capitalization ratio breached by a growing parent loan; interest accrued for years and never paid; and a U.S.-resident owner borrowing from their Canadian corporation and never repaying (a deemed dividend with withholding).

Key takeaways

• Intercompany interest must be at an arm's-length rate, documented — Canada imputes interest on an unreasonably low-rate loan from a Canadian corporation to a non-resident (section 17), with an exception for controlled foreign affiliates' active businesses.
• The treaty eliminates withholding on related-party interest in both directions with the right forms (W-8BEN-E to the U.S. borrower; NR301 or NR302 to the Canadian borrower).
• U.S. borrowers face section 163(j)'s 30 percent cap (small businesses exempt) and the anti-hybrid rules; Canadian borrowers face thin capitalization's 1.5-to-1 ratio and EIFEL.
• Thin capitalization's disallowed interest becomes a deemed dividend with Part XIII withholding.
• Upstream loans have their own rules in each country — section 956 for a Canadian CFC lending to a U.S. parent; section 90(6) for a foreign affiliate lending to a Canadian parent; section 15(2) for a non-resident shareholder borrowing from a Canadian corporation.
• Debt that behaves like equity is recharacterized — a written agreement, a repayment schedule, and interest actually paid are the defense.

The intercompany loan file

Agreement (amount, rate, term, security, schedule); board resolutions both sides. Arm's-length rate support. Interest accrued and paid. Withholding forms; NR4 or 1042-S if applicable. U.S. 163(j) and anti-hybrid review; Canadian thin capitalization ratio and EIFEL. Upstream loan clocks (956; 90(6); 15(2)). The payments actually made are the record that keeps debt from becoming equity.

Worked example

An Alberta oilfield services company lends US$3 million to its new Texas subsidiary to buy equipment: a five-year agreement at a rate supported by the subsidiary's bank quote for comparable secured debt, quarterly interest paid in cash, and a W-8BEN-E from the parent so the subsidiary withholds nothing (treaty zero on related-party interest); the subsidiary's interest deduction passes section 163(j) (its adjusted taxable income supports it) and the parent reports the interest in Canada. The parent had first proposed an interest-free loan — the desks noted that section 17 wouldn't impute interest in Canada (the wholly owned Texas subsidiary is a controlled foreign affiliate using the money in its active business, so section 17(8) applies, and section 247(7) keeps transfer pricing out of it), but an interest-free loan would give the subsidiary no U.S. interest deduction, so an arm's-length rate was chosen to keep both countries comfortable. A separate case: a Montreal company's U.S.-resident owner borrowed C$400,000 from the corporation to buy a Florida condo and never repaid it — after the one-year window, a deemed dividend to a non-resident under section 15(2) with Part XIII withholding the corporation should have remitted (the Quebec cross-border guide's second layer), and a U.S. mismatch — the IRS treats the advance as a distribution only if it isn't bona fide debt, so the Canadian withholding may not line up with U.S. income for her foreign tax credit.

Official sources

IRS Publication 597 explains: “Generally, Canadian source interest received by U.S. residents is exempt from Canadian income tax. The exemption does not apply if the owner of the interest carries on, or has carried on, a business in Canada through a permanent establishment and the debt on which the income is paid is effectively connected with that permanent establishment.” — Internal Revenue Service, Publication 597 (10/2015), Information on the United States–Canada Income Tax Treaty, https://www.irs.gov/publications/p597

The CRA explains: “Not all corporations with an address in the United States will be entitled to treaty benefits under the Limitation on Benefits article in the Canada–United States income tax treaty. Therefore, the CRA recommends that the payer get a completed Form NR301 or similar information from the payee before applying a reduced tax treaty rate.” — Canada Revenue Agency, More information on forms NR301, NR302, and NR303, https://www.canada.ca/en/revenue-agency/services/forms-publications/information-on-forms-nr301-nr302-nr303.html

Practitioner note

A loan between related companies across the border is examined by two tax systems at once: the rate has to be arm's length for both, the borrower's deduction has to survive section 163(j) or Canada's thin capitalization and EIFEL rules, and the upstream loans — the Canadian corporation lending to its U.S. owner, the subsidiary lending to its parent — each have a clock that turns them into dividends. Our desks write the agreement, document the rate, pay the interest in cash on schedule, file the forms that bring treaty withholding to zero, and track the ratios and the clocks — because debt that never gets repaid is, in both countries, equity with a deduction someone will disallow.

See also: For related guidance, see cross-border shareholder loans and section 15(2) and transfer pricing between related Canadian and U.S. companies; and browse every cross-border tax topic guide, organized by situation.

Next step

Fairlight Accounting is a cross-border accounting and tax practice with a U.S. Tax Desk and a Canadian Tax Desk. Our U.S. Tax Desk and Canadian Tax Desk handle cross-border intercompany financing — arm's-length rate documentation, section 17 imputed interest analysis, treaty withholding documentation, section 163(j) and anti-hybrid review, Canadian thin capitalization and EIFEL computations, upstream loan rules under sections 956, 90(6), and 15(2), and debt-versus-equity support. See pricing or book a call.