Basic opportunity calc
Simple question: if you borrow at 7 % and invest your capital elsewhere, the arbitrage depends on the expected return of that investment.
- Long-term equities (real S&P 500): ≈ 7–10 % annual historical. Tight margin.
- Government bonds: 3–5 % in 2025-2026. Borrowing at 7 % to invest at 4 % = guaranteed loss.
- US rental real estate: 4–8 % gross cap rate, less expenses. Variable.
- Cash at FX broker or savings account: 4–5 % in 2025. Same guaranteed loss.
Conclusion: if your alternative to cash is paying 7 % interest, you must firmly believe in achieving > 7 % net after tax on the alternative investment. Plausible in long-term equities, but not guaranteed.
US + Canadian tax impact
US side
If the property is rented, mortgage interest is deductible from rental income on Form 1040-NR (foreign person filing US return). Reduces US tax on rental income.
If the property is personal/snowbird residence without rental, interest is not deductible on the US side (you have no US income).
Canadian side
CRA treats mortgage interest as follows:
- Rented US property: interest deductible from rental income reported in Canada (with Form 8833 treaty Canada-US adjustment as needed).
- Personal secondary residence: interest not deductible. It's personal consumption.
Consequence
For a non-rented snowbird residence, the mortgage costs full price on both sides (no US deduction, no CA deduction). Opportunity calc is unfavorable.
For a rental property, interest becomes partially deductible, reducing effective cost by 1–2 % depending on your tax bracket.
FX risk
Buying cash from Canadian funds means converting CAD→USD all at once. If CAD weakens after your conversion, you pay more in CAD for the same USD.
US mortgage lets you spread FX risk: you pay the monthly USD payment, so you buy USD regularly. If CAD strengthens over 30 years, you save progressively.
But the opposite is also true: if CAD weakens, payments become more expensive in CAD each month.
Hybrid strategy
Buy cash via Canadian HELOC (in CAD), then finance after purchase via US mortgage (cash-out refinance) if rates become favorable. Provides flexibility and immediate competitiveness.
Offer competitiveness
In tight markets (snowbird season, multi-offer), a cash offer is significantly more competitive than a financed offer:
- No financing contingency = less risk for the seller.
- No mandatory appraisal contingency = no block if low appraisal.
- Quick closing possible (15–30 days).
A cash buyer can often obtain 3–7 % off asking in tight markets, which can offset the lack of leverage.
Four numbered scenarios
On a $500,000 USD property, over 10 years, assuming stable CAD 1.38 USD, 7 % borrowing rate, 8 % equity return, 35 % combined tax rate.
Scenario A: cash purchase, non-rented personal property
- Initial capital: C$690,000.
- Annual costs (taxes, HOA, insurance): US$18,000/year.
- 10-year total: C$690,000 + C$180,000 = C$870,000 in costs (before appreciation).
Scenario B: 30 % cash + 70 % mortgage, non-rented personal property
- Down payment $150,000 USD (C$207,000).
- $350,000 mortgage at 7 % over 30 years: payment ≈ $2,330/month = $27,960/year in interest+principal.
- "Saved" capital (C$483,000) invested at 8 % gross, 5.2 % net after tax = ≈ C$800,000 after 10 years.
- Total borrowed + invested may produce slightly higher wealth, but with market risk.
Scenario C: 30 % cash + 70 % mortgage, rented property
- Net US rental income (after deductible interest): $8,000/year.
- Interest also deductible on the CA side.
- Effective mortgage cost drops to ≈ 5 % effective.
- Opportunity calc becomes clearly favorable to leverage.
Scenario D: cash purchase via Canadian HELOC
- HELOC at prime + 0.5 % = 6 % in Canada.
- HELOC interest not deductible (unless borrowing in CA to generate CA income).
- Cash offer competitiveness + repayment flexibility.
- Limited FX risk (HELOC payment in CAD).
Strategy by profile
- Snowbird personal residence, capital available: pay cash. Real opportunity cost but no leverage risk or underwriting.
- Long-term rental investor: mortgage favorable. Deductible interest, leverage boosts return.
- Buyer without total capital: mortgage required. Negotiate terms well.
- Urgent buyer in tight market: cash via Canadian HELOC for competitive offer, refinance in USD later if appropriate.
- High net worth with risk aversion: cash. Peace of mind beats marginal optimization.
Every figure, rate, threshold, and deadline in this guide is drawn from a verifiable primary source listed at the bottom of the page. The article is updated whenever the underlying rules change, with a fresh review date stamped at the top.
Sources and references
All sources were publicly accessible at the last review date. Figures and rules may change; verify the current version before any decision.
- IRS Publication 519 — U.S. Tax Guide for Aliens. irs.gov/p519
- IRS Publication 527 — Residential Rental Property. irs.gov/p527
- Canada-US Tax Treaty — Articles VI, XIIIA. canada.ca/treaty/usa
- ARC — Folio S5-F2-C1 — Foreign Tax Credit. canada.ca/folios
- Bank of Canada — historical USDCAD exchange rates. bankofcanada.ca
Logical next step
If you finance, knowing how to build US credit can accelerate the process.