The Smith Manoeuvre generates more questions than any other strategy we support — usually the same eight, in roughly this order. Here are the plain-English answers we give across the table, and the longer version lives on our Smith Manoeuvre service page.
It's a strategy for gradually converting your mortgage — whose interest is not deductible — into investment borrowing, whose interest generally is. Each regular mortgage payment reduces your principal; a readvanceable mortgage makes that repaid amount available again as a line of credit; you borrow it back and invest it in income-producing assets. Over the years, non-deductible mortgage debt is steadily replaced by deductible investment debt, while an investment portfolio builds alongside.
Yes. The strategy uses a long-standing principle of Canadian tax law: interest on money borrowed to earn income is generally deductible. There's no loophole being exploited and nothing to hide. What the CRA does expect — and checks — is that the borrowed money genuinely went to eligible income-earning investments and that your records prove it. The strategy is legal; sloppy execution of it is where people get hurt.
You need a readvanceable mortgage — one that pairs the mortgage with a line of credit whose room grows automatically as you pay down principal. Not every lender offers one and the features differ meaningfully between them. A standard mortgage can often be converted or moved, but that's a decision to make deliberately, ideally at renewal time.
Use of funds — nothing else. Interest is deductible because the borrowed money was used to earn income, typically investments held in a regular taxable account. Money borrowed and invested inside registered accounts doesn't qualify, and borrowing that drifts to personal spending taints the deduction. The security for the loan (your house) is irrelevant; the destination of each borrowed dollar is everything.
Commingling. Running borrowed funds through the family chequing account, or using the investment line of credit for even one personal purchase, blends deductible and non-deductible borrowing — and every statement from then on needs an allocation calculation to defend the deduction. The fix is discipline: the line of credit feeds investments and nothing else, through a dedicated account, with a paper trail from every advance to every purchase. This is the part of the strategy that's pure bookkeeping, and it's the part that fails most often.
It can pair well with them. Rental owners have a related tool — often called the cash flow dam — where rental income accelerates paydown of the non-deductible home mortgage while property expenses are funded by borrowing, shifting debt from non-deductible to deductible faster. The mechanics are strict and the tracing requirements even stricter, so this is a version to implement with professional support rather than a blog post.
Anyone uncomfortable investing borrowed money, full stop — the strategy adds leverage, and leverage cuts both ways in down markets. It's also a poor fit for tight cash flow, short time horizons, unstable income, or anyone who won't maintain the record-keeping discipline. The tax deduction is a feature of the strategy, not a reason to adopt risk you wouldn't otherwise take.
We're the record-keeping and tax side of the strategy: books that keep borrowed funds traced from advance to investment, clean separation of deductible and non-deductible interest, and returns that claim the deduction with documentation behind it. We work alongside your licensed advisor, who handles the investment decisions — the details are on our Smith Manoeuvre page.
The takeaway: the Smith Manoeuvre is legal, established, and unforgiving of messy records. If you're running it — or about to — book a free consultation and we'll make sure the paper trail can carry the strategy.
This post is general information, not tax advice for your specific situation.
