The core risk: assumed debt is payment, and payment above your cost is taxed now
When your corporation takes over the mortgage, the tax system treats the assumed balance as money the corporation paid you for the property, and a section 85 election cannot set the transfer price below what you were paid. That is the whole trap in one sentence. The rollover works by electing a transfer price as low as your tax cost, but the elected amount can never sit below the non-share payment you receive, and an assumed mortgage is exactly that kind of payment.
Suppose the property's tax cost is 300,000 dollars and the mortgage has been refinanced up to 450,000. The corporation assuming that mortgage has paid you 450,000, the election cannot go below it, and the 150,000 difference is a gain taxed in your hands in the year of transfer, with no cash proceeds to pay the bill, because the money went to the bank years ago when you refinanced. This is how a transfer marketed as tax-deferred produces a real assessment: the deferral machinery worked, and the debt overrode it.
The pattern to watch for is a property owned for years, depreciated, and refinanced as values rose, because refinancing pushes the loan toward today's value while the tax cost stays at yesterday's price. If your mortgage balance is anywhere near your original cost, get the actual numbers pulled before anyone drafts anything. The general mechanics of the election, the share consideration and the deadlines live in our page on tax-deferred rental transfers; this page is about what the mortgage does to them.
The quieter version: recapture when the debt tops the building's depreciated cost
Even a mortgage safely below your total cost can trigger tax, because the transfer is not one election but several, and the debt has to be split among them. Land and building are separate properties for a section 85 transfer, each with its own elected amount, and the assumed mortgage must be allocated across them as payment. Any slice of debt allocated to the building above its undepreciated capital cost forces the building's elected amount up, and the excess comes back into your income as recaptured CCA, taxed in full rather than as a half-taxed capital gain.
This bites landlords who claimed CCA steadily, since years of deductions can pull the building's undepreciated cost far below both the original price and the mortgage. The planning response is allocation: assign debt first to the land and to any room above the building's depreciated cost, and keep the recapture layer intact where the numbers allow it. There is real room to plan here, but only before the agreement is signed, because the allocation is part of the deal terms, not a year-end adjustment.
The practical lesson is that three numbers decide this transfer before any lawyer is involved: the mortgage balance, the property's cost, and the building's undepreciated capital cost after every year of CCA. We pull all three in the first meeting, because they tell us whether this is a clean rollover, a partial problem, or a transfer that should not happen.
Three places the mortgage can land, and what each one costs
You have three realistic options for the debt itself, and the choice drives most of the tax and most of the friction.
| What happens to the mortgage | Tax result | Practical result |
|---|---|---|
| The corporation assumes it | The balance counts as payment to you; anything above your allocated tax cost is taxed now as gain or recapture | Lender consent, fresh underwriting of the corporation, your personal guarantee, land transfer tax calculated on a value that includes the debt |
| You keep it personally | No assumed-debt problem, so a full deferral is possible on paper | Your loan is now secured by an asset you no longer own, which most lenders will not allow, and the interest may stop being deductible because the borrowing no longer funds property you hold |
| The corporation refinances at closing | Cash paid to you counts as payment too, but cash up to your tax cost comes out without triggering the gain | A new loan at today's rates on commercial terms, discharge or penalty costs on the old mortgage, and a corporation underwritten from scratch |
None of the three is free, which is the point of seeing them side by side. Assumption is the default and carries the boot problem; keeping the debt personally usually fails at the lender and quietly wrecks interest deductibility; refinancing is often the cleanest tax answer and the most expensive banking answer. The right choice depends on your rate, your penalty, your cost numbers and your lender's appetite, which is why we model all three before recommending one.
The lender, the insurer and the bills the election never touches
Moving title without your lender's consent typically defaults the mortgage, so the bank is a gatekeeper in this transaction, not a formality. Consent in practice means the corporation applies as a new borrower: financial statements, your guarantee, sometimes a rate reset to today's pricing, and fees along the way. If the mortgage is default-insured, add the insurer's rulebook, which generally does not contemplate corporate borrowers on this kind of loan at all, and the answer can simply be a forced refinance. Budget the banking workstream as seriously as the tax one.
Then come the taxes the election has no power over. Ontario land transfer tax applies when the property is conveyed to the corporation, calculated on consideration that includes the assumed mortgage and the shares issued, so a heavily mortgaged property guarantees a substantial taxable value, and property in Toronto pays the municipal tax on top. HST is usually quiet for a used residential rental, which is generally exempt, but commercial and mixed-use property brings self-assessment mechanics where the corporation's registration needs to be in place before closing, not after.
These costs land at closing and in cash, which changes the economics of marginal transfers. A transfer that defers a modest gain but writes a large land transfer tax cheque has negative value for years, and we have told owners exactly that at the analysis stage. Whether the move belongs in your structure at all is the bigger question, and it is the subject of whether rentals belong in a corporation in the first place.
Paper risks: shareholder benefits, broken deductions and a late election
Getting the consideration wrong creates tax out of thin air, because the rules police the gap between what you gave and what you got. If the corporation assumes debt and issues shares worth more than the property, or the paperwork lets value pass to you beyond what the property supports, CRA can tax the difference as a shareholder benefit, with no offsetting cost anywhere. The defence is boring and effective: a supportable valuation, share terms that match it, and an agreement that prices the debt assumption explicitly.
Interest deductibility deserves its own line, because it breaks silently. Deductibility follows what borrowed money is used for, and a transfer rearranges exactly that: debt kept personally traces to a property you no longer own, and even assumed debt needs the corporation's paper trail to start cleanly. Handled properly, the corporation deducts interest against its rents; handled casually, deductions that survived for years stop being supportable, and nobody notices until an auditor does.
The election itself has a clock. The T2057 is due by the earliest tax-return deadline of anyone in the transaction for the year of transfer, late filings are accepted for up to three years with a penalty that grows over time, and beyond that window the deferral is gone entirely, leaving a fair-market-value sale in a year already closed. The form, the valuation, the allocation schedule and the debt paperwork should be one package prepared with the transfer, which is how we run it as a Strategic Project.
After closing: the corporation has to carry the loan, and the answer has to stay worth it
The risks do not end at closing, because the mortgage now has to be serviced from rent that is taxed inside the corporation at close to the top personal rate. A payment schedule that was comfortable against your salary can be tight against after-tax corporate rent, and pulling cash out of the corporation to help creates taxable dividends, the exact leak the structure was supposed to manage. Before transferring, we build the corporation's cash flow for the first few years, mortgage included, and check that the structure carries itself.
It is worth restating why people accept all of this, because the risks only make sense against the reason. The good reasons are structural: separating the property from personal exposure, consolidating it beside other corporate assets, and setting up share-based estate planning that a personally held deed can never support. As a business estate planning CPA in Ontario, we see the mortgaged-transfer question most often as step one of a family plan, and the aftermath, the intercompany accounts, the group cash flow and the ongoing filings, is covered in our real estate investment company planning page.
Five facts decide how risky your transfer actually is:
- The mortgage balance against the property's tax cost, which decides whether immediate gain is forced.
- The building's undepreciated capital cost, which decides whether recapture joins it.
- Your lender and any mortgage insurance, which decide whether assumption is even available or a refinance is forced.
- The land transfer tax bill, driven by value and doubled in Toronto, which sets the cash cost of entry.
- The corporation's cash flow after tax, which decides whether the structure can carry the debt it just took on.
We price all five in a written analysis before anything is signed, alongside your lawyer and lender. If the numbers say wait, restructure the debt first, or leave the property where it is, you will hear that clearly, and it will cost you a discovery call rather than a reassessment.
