Smith Manoeuvre in Canada: how mortgage interest can become deductible, and the risks

Short answer: The Smith Manoeuvre in Canada is a strategy for gradually turning non-deductible mortgage debt into investment debt whose interest may be tax-deductible. You use a readvanceable mortgage, where your HELOC limit grows as you pay down principal ^[3], re-borrow each dollar of principal you repay, and invest it in non-registered, income-producing investments. CRA generally allows a deduction for interest on money borrowed and used to earn income such as interest and dividends ^[1][2]. It doesn't reduce what you owe, and it adds investment and rate risk, so it suits a fairly narrow group.

This guide is for homeowners with a stable income, a long time horizon and an interest in investing who want to understand how the strategy works, what the CRA rules require and where it can go wrong. It's general information, not tax or investment advice. The mortgage side starts with our home equity line of credit page.

How the Smith Manoeuvre works

1. Set up a readvanceable mortgage. This is a HELOC combined with a mortgage, from the same lender; your available credit increases as you pay down the mortgage principal ^[3]. See our readvanceable mortgage guide.
2. Make your regular payments. Each payment reduces the mortgage principal.
3. Re-borrow the principal you paid. Draw that amount from the HELOC portion.
4. Invest it in a non-registered account in investments that can produce income, such as dividends or interest.
5. Claim the HELOC interest on line 22100 of your return, keeping records that link the borrowing to the investments ^[2].

Your total debt stays about the same. What changes is its purpose: the mortgage on your home shrinks, and the investment line grows.

What the CRA rules require

Interest on a mortgage for the home you live in is a personal cost, so it isn't deductible. The deduction comes from the investment borrowing, and CRA's interest deductibility folio sets out the tests ^[1]:

• Use and purpose. The borrowed money must be used to earn income from a business or property, with a reasonable expectation of income when you invest ^[1].
• Current use and tracing. What counts is how the money is used now, and the onus is on you to trace the borrowed funds to an eligible use ^[1].
• Income, not just growth. If the only earnings an investment can produce are capital gains, you can't claim the interest ^[2]. CRA generally accepts common shares on the basis that dividends can reasonably be expected ^[1].
• No registered plans. You can't deduct interest on money borrowed to contribute to an RRSP, TFSA, FHSA, RESP or similar plans ^[2].
• Keep the line clean. If one line of credit is used for both personal and investment purposes, CRA applies repayments proportionally across both, so you can't pay off just the personal part ^[1]. Keeping investment borrowing in its own account makes tracing far easier ^[1].

Considering a readvanceable mortgage? A licensed 8Twelve agent can compare readvanceable products across 65+ lenders, including how the HELOC sub-accounts are set up, OAC. Compare HELOC options

Worked example: the first 10 years

Example (illustrative): a homeowner pays down about $1,000 of principal a month and re-borrows it each month to invest. We've assumed a HELOC rate of prime plus 0.50 points; with prime at 4.70% as of November 4, 2026 ^[6], that's 5.20%. We've also assumed a 30% marginal tax rate. To keep it simple, the principal portion stays at $1,000 a month and interest is shown on the year-end balance.

In real life the principal portion of each payment grows over time, rates change, and the deduction depends on your own tax situation. The tax saving is only part of the picture: the result depends mostly on how the investments perform after costs, which no one can promise.

The table shows the trade-off clearly. The deduction is real, but it's a fraction of the interest you pay. The strategy only comes out ahead if the investments earn more, after tax, than the interest they cost.

The risks to weigh first

• Investment risk. Borrowing to invest can help your money grow, but it can also lead to larger losses, and you still have to repay the loan plus interest either way ^[5].
• Rate risk. HELOC rates are usually variable and tied to your lender's prime rate, which can change when the Bank of Canada changes its policy rate ^[3]. If rates rise, the cost of carrying the investment line rises too.
• Your home secures it. A HELOC is secured by your home, and if you don't pay back what you owe, your lender may take possession ^[3].
• Less equity, fewer options. Borrowing against your home reduces your equity, which can limit your options if you want to sell ^[3].
• Interest-only lines don't pay themselves off. FCAC notes that if you only pay the interest, you won't pay off the loan ^[3].

New Brunswick's financial and consumer services regulator suggests leveraging may not be appropriate for people who are retired or nearing retirement, need the money within five years, have a low risk tolerance or would carry heavy debt payments relative to income ^[5].

What you need on the mortgage side

• Equity. FCAC says a HELOC combined with a mortgage needs at least 20% equity ^[3].
• Limits. Under OSFI's guidance for federally regulated lenders, the revolving, non-amortizing HELOC portion is capped at 65% of your home's value, and the combined total can't exceed 80% ^[4]. Our HELOC limit guide walks through the math.
• Qualifying. You must pass a stress test to qualify for a HELOC at a bank ^[3].
• Separate sub-accounts. In our experience, many readvanceable products let you split the HELOC into separate accounts, which helps keep investment borrowing apart from personal spending.
• Costs. Expect appraisal, legal and possibly administration fees to set it up ^[3], and a penalty if you break your current mortgage mid-term. Our refinance costs guide lists them.

The Smith Manoeuvre in Canada can turn mortgage interest into a possible tax deduction over time, but it's an investment strategy first and a mortgage strategy second. It works best for people with stable income, a long horizon and the discipline to keep records. Have a tax professional and a licensed investment adviser review it with you, and use our mortgage payment calculator to see how much principal you pay down each year.

This article is for general information only and isn't financial, investment, legal or tax advice. 8Twelve Mortgage does not provide tax or investment advice; speak with a qualified tax professional and a registered investment adviser before borrowing to invest. Rates, products and terms change without notice and are available on approved credit (OAC). The rate and terms you qualify for depend on your individual financial situation, including credit, income, property and loan-to-value. "Best rates" means the most suitable options available for your situation, not a guarantee of the lowest rate. Example rates and payments are for illustration only, as of November 10, 2026, and are not an offer. 8Twelve Mortgage arranges mortgages through 65+ lenders and does not lend directly. Licensed across Canada — see our licences.

The 5.20% HELOC rate (prime of 4.70%, per Bank of Canada data for November 4, 2026, plus an assumed 0.50 points), the $1,000 monthly principal and the 30% marginal tax rate are assumptions for illustration, not quotes or advice. Tax rules are summarized from CRA's Income Tax Folio S3-F6-C1 and line 22100 guidance, checked November 10, 2026, and can change.