The Smith Manoeuvre: How to Make Mortgage Interest Tax-Deductible in Canada

The Smith Manoeuvre is a way to convert the non-deductible mortgage on your home into a tax-deductible investment loan, one payment at a time. This guide explains how it works, the CRA rules that make the interest deductible, what a 25-year projection looks like once the interest cost is included, and the risks. It is part of WealthNorth’s guide to real estate investing in Canada.

Interest on a mortgage for your own home isn’t deductible in Canada. Interest on money borrowed to earn investment income generally is. The strategy moves your borrowing from the first category to the second without increasing the total debt.

How the Smith Manoeuvre works

1. You hold a readvanceable mortgage: a mortgage and a home equity line of credit (HELOC) under one registered charge, where the HELOC limit rises as the mortgage principal falls. Readvanceable mortgages explains the products and how the segments work.
2. Each mortgage payment reduces the principal. The HELOC limit rises by the same amount.
3. You borrow that newly available amount from the HELOC, ideally from a sub-account used only for investing.
4. You invest it in a non-registered account, in investments that can produce interest or dividends.
5. The HELOC interest is deductible on line 22100 of your return. Investment income is taxable each year.
6. Repeat with every payment. By the end of the amortization the mortgage is gone and the same amount is owed on a fully deductible investment line of credit, with a portfolio on the other side.

Lenders can offer a revolving HELOC of up to 65% of the home’s value under OSFI’s Guideline B-20, including when it is linked to a mortgage, and the combined mortgage and HELOC on a home without default insurance can’t exceed 80% of its value. You need enough equity to open the readvanceable structure; after that, the re-borrowing room comes from your own payments.

The CRA rules that make the interest deductible

The deduction rests on paragraph 20(1)(c) of the Income Tax Act, and the CRA’s folio on interest deductibility (S3-F6-C1) sets out how it is applied.

For the wider rules on when mortgage interest is deductible, including rentals and mixed-use homes, see when mortgage interest is tax-deductible.

A 25-year projection, costs included

The projection below uses illustrative assumptions, not a forecast: a $400,000 mortgage at 4.5% (compounded semi-annually, as Canadian fixed-rate mortgages are) over 25 years, every month’s principal re-borrowed and invested, a 6% HELOC rate, a 6% average annual portfolio return with all income reinvested, and a 40% marginal tax rate. The HELOC interest is paid monthly from the household’s own cash flow, and the tax refunds are not reinvested.

Two things the table makes visible:

• Total debt never changes. The mortgage and the HELOC always add up to the original $400,000 balance; only the deductible share grows.
• The interest is a real cost. Over 25 years the household in this example pays about $244,000 of HELOC interest out of its own cash flow and gets about $98,000 back in refunds, a net cost of about $147,000. By the end it is paying about $2,000 a month in HELOC interest. The strategy comes out ahead only if the portfolio’s after-tax return beats the after-tax cost of the borrowing; with lower returns, a higher HELOC rate or a bad sequence of markets, it can come out behind.

The monthly principal portion that drives the whole strategy depends on your rate and amortization; the mortgage amortization calculator shows how it grows over time.

Accelerating the conversion

The standard version converts the mortgage over its full amortization. Three variations speed it up:

• Tax refunds to the mortgage. Each year’s refund goes on the mortgage as a prepayment, which frees up the same amount of HELOC room to re-borrow and invest.
• Investment income to the mortgage. Dividends and distributions are used as prepayments, then re-borrowed and invested. The income is still taxable in the year it is paid, and the portfolio no longer compounds it directly.
• Cash damming (business owners and landlords). Business or rental expenses are paid from the HELOC, and the business income that would have paid them goes on the mortgage instead. The HELOC balance used for the business is deductible. This needs careful records, and an accountant can review the setup.

Prepayment limits on the mortgage portion still apply, so check the privileges on your product.

Risks

Who it suits and who it doesn’t

It tends to suit homeowners with a long time horizon, stable income that can carry a growing interest bill, a higher marginal tax rate (which makes each dollar of interest worth more as a deduction), and the temperament to hold through market falls. It tends not to suit anyone planning to sell within a few years, anyone whose income is uncertain, anyone already carrying high-interest debt, or anyone who hasn’t used their registered room: tax-free or tax-deferred growth in a TFSA or RRSP doesn’t depend on a deduction at all.

Common mistakes

• Mixing accounts. Paying personal expenses from the investment HELOC segment makes the borrowing hard to trace and shrinks the deductible amount.
• Buying investments that can’t produce income. Assets whose only possible return is a capital gain don’t support the deduction.
• No records. Keep a log of every draw, the matching purchase, annual HELOC interest statements and brokerage statements.
• Selling without reinvesting. Spending sale proceeds generally ends the deduction on that part of the loan.
• Forgetting to claim it. The interest goes on line 22100 each year.

Related strategies

The Smith Manoeuvre is one way of borrowing against your home to invest. Using a HELOC or refinance to fund a rental down payment, or a lump sum to invest, is covered in using home equity for investment. Current HELOC pricing is compared in HELOC rates in Canada, and the simpler choice between prepaying the mortgage and investing is covered in should you pay off your mortgage or invest.