What questions should you ask before mortgage porting?

Short answer: when mortgage porting makes sense

Mortgage porting means transferring your existing mortgage balance, interest rate, and contract terms from the home you are selling to the home you are buying. Porting is worth investigating when your current rate or special features are significantly better than current market options and you want to avoid breaking charges, but it is not automatic and it is not always the cheapest route. For an official summary of how portability works and when it can help, consult the Government of Canada mortgage guidance and the federal consumer booklet on mortgage shopping for practical checks before you decide (Government of Canada mortgage guide, Buying Your First Home).

Seven mistakes and eligibility checks to run before you commit

Below are seven specific checks. Treat each one as a stand-alone decision test: if you cannot answer the question clearly, pause and get a professional review before signing anything.

1. Assume portability only after you read your mortgage contract

Not every mortgage is portable. The first and simplest test is to read your mortgage contract or ask your lender for the portability clause. If the contract does not explicitly allow porting, you cannot port. Even when a contract mentions portability, it usually includes conditions. The Government of Canada recommends checking eligibility with your lender because wording and allowed scenarios vary by contract and lender (Government of Canada mortgage guide).

2. Verify lender approval criteria will be reapplied to the new purchase

Porting keeps your mortgage terms, but the lender typically re-underwrites the application for the new property. That means income, credit score, the new property’s appraisal, and any change in household composition will be reassessed. If the new property does not meet the lender’s property standards or your finances changed, the lender can deny the port. Ask the lender: will you re-run my file using the same underwriting rules and what property conditions could block porting?

3. Confirm whether you can port the whole mortgage, part of it, or add a top-up

Some lenders allow full porting of the outstanding balance, others allow partial porting, and many permit a port plus a top-up (new borrowing added at the time of transfer). Partial porting and top-ups are common, but the new portion may be offered at a different rate or with different amortization requirements. The federal consumer guide explains the concept of transferring some or all of the terms and balance to a new property and why borrowers choose partial porting when they want new funds for renovations or a larger purchase (Buying Your First Home).

4. Compare the cost to break the mortgage versus the cost to port

Porting often avoids prepayment penalties, but it can carry administrative fees, bridging costs, or a blended rate if you top up. If your current rate is only marginally better than new market rates, the cost of arranging bridging finance or paying administrative charges might make breaking and refinancing more economical. The Government of Canada recommends weighing prepayment penalties against the likely savings from your existing rate before deciding (Government of Canada mortgage guide).

5. Check timing: closing dates, bridging needs, and simultaneous transactions

Porting typically requires your sale and purchase closings to align, or a plan for short-term financing. If your sale closes after your purchase closing, you may need bridge financing or a conditional arrangement with your lender. Mismatched closing dates are one of the most common reasons porting plans fail. Ask your lender and your lawyer how they will handle a gap between closings and what documents they need to confirm when.

6. Understand CMHC portability rules and the two-year premium credit

If your mortgage is CMHC-insured, special portability rules apply. CMHC allows portability for insured loans provided at least one borrower on the new mortgage is a borrower from the original insured mortgage, the new property meets occupancy and suitability requirements, and a premium credit may apply if you port within two years. Check the CMHC portability details before relying on any assumed premium benefits (CMHC portability page).

7. Don’t skip a rate shop: portable features may still lose to a new competitive rate

Even if you can port, the portable mortgage may carry restrictions such as a shorter remaining amortization, limited repayment flexibility, or a higher blended rate when topped up. Always run a net-cost comparison: include penalties avoided, expected new rate if you refinanced, administrative fees, and the value of features such as prepayment privileges or convertible terms. A local broker can run side-by-side scenarios quickly using affordability and eligibility tools.

How CMHC portability works and what to check first

For CMHC-insured mortgages, portability is available under specific conditions. The key points to verify are borrower continuity (at least one original borrower must be on the new loan), property suitability and occupancy standards, and timing for any premium credit. If you plan to port within two years and expect a premium credit, confirm the exact credit calculation with your lender and the CMHC guidance to avoid surprises (CMHC portability page).

Porting and top-ups: what usually happens to the extra borrowing

When you add a top-up at the time of porting, lenders typically split the mortgage into two parts on paper: the portable portion with your original rate and terms, and the new portion at the lender’s current rate. Some lenders offer a blended rate for the combined balance. Important questions to ask are: how will amortization be handled, will the top-up be insured or uninsured, and how will payments be structured during the blended period? Your answers determine monthly payment changes and long-term cost.

Timing and bridging finance: avoid the common closing mismatch

Plan closing dates early. If your purchase closes before your sale, ask about short-term bridging options, conditional advances, or extendable closing arrangements. Bridging often incurs interest and fees, and it can change the economics of porting. If the lender requires a pre-sale condition to complete porting, treat that condition as a potential point of failure and have contingency financing in place.

A simple decision matrix: port, break and refinance, or hybrid

• Port when: your existing rate and contract features materially beat current offers, the lender will approve the new property on re-underwriting, and timing can be managed without expensive bridging.
• Break and refinance when: penalties plus other porting costs exceed the savings from your current rate, or the lender will not approve the new purchase for portability reasons.
• Hybrid when: partial porting plus a top-up gives the best balance of rate, access to equity, and repayment flexibility; confirm blended rate and amortization before agreeing.

Real objections and lender red flags to watch for

Watch for these answers from a lender or broker because they require further validation: "We will port it, but only if the new property appraises at a higher value"; "We can only port without a top-up"; or "You must wait until your sale completes before we start paperwork." Any vague timelines, refusal to provide portability terms in writing, or unexpected clauses in the portability rider merit a second opinion from a licensed broker or lawyer. If you encounter pushback, ask for a written explanation and the exact contract clause that permits or restricts porting.

Practical next steps and a short document checklist

To move forward without surprises, follow this short plan:

1. Locate your mortgage contract and find the portability clause, then request written confirmation from the lender about porting eligibility.
2. Gather documents the lender will re-assess: recent pay stubs, tax returns if self-employed, a credit report, and details on the new property (listing, survey, or builder specs).
3. Decide whether you need a top-up and ask for a blended-rate example and amortization options.
4. Compare the break cost (prepayment penalty) to the expected savings if you port, including any bridging costs.
5. Use a broker to run side-by-side scenarios and to shop alternative lenders if portability is denied or uneconomic.

If you want a fast eligibility check, use the MiiGrowth Instant Eligibility tool and calculators to model your options and book a consultation with a licensed broker based in Mississauga.

FAQ

What does porting a mortgage mean?

Porting transfers some or all of your existing mortgage balance, interest rate, and contract terms from the home you are selling to the home you are buying while remaining with the same lender. Government guidance explains portability as a way to keep favourable mortgage features while avoiding prepayment charges in some cases (Government of Canada mortgage guide).

Can I port a CMHC‑insured mortgage and still get a premium credit?

Yes, CMHC allows portability for insured loans, and a premium credit may be available if you port within two years, provided at least one original borrower remains on the new mortgage and the new property satisfies CMHC’s suitability rules. Confirm the exact credit with your lender and CMHC documentation (CMHC portability page).

Can I port my mortgage and add a top‑up at the same time?

Often you can, but the lender may price the new funds at a different rate, require different amortization, or split the mortgage into original and new portions. Request a written example that shows the blended payment and total cost before agreeing.

What happens if my lender refuses to allow porting?

If a lender refuses, you will typically need to either pay the prepayment penalty and refinance with a new lender, or negotiate a hybrid solution such as a partial port plus a new loan. A broker can compare net costs and alternative lenders to find the best path forward.

How does timing affect porting and will I need bridging finance?

Timing is critical. If your purchase closes before your sale, you may need short‑term bridging finance. If dates do not align, porting can fail even when your mortgage is technically portable. Always plan closing logistics with your lender and lawyer and obtain written contingency steps.

Final question to consider

Before you decide, ask: will porting preserve enough financial benefit and flexibility after accounting for re-underwriting, top-up pricing, bridging costs, and any CMHC conditions to justify avoiding a break and refinance?

Get a local porting eligibility check with a licensed Mississauga broker

If you are in Mississauga or Southern Ontario and want a no-obligation porting eligibility check, MiiGrowth offers an instant eligibility tool and personalized rate-shopping to compare porting versus breaking or refinancing. MiiGrowth is a Mississauga-based mortgage brand led by a licensed mortgage professional backed by Mortgage Alliance; you can use the online tools or book a consultation for a tailored comparison at MiiGrowth. Ready to check if porting is right for you?