Co-Signer

A co-signer is a person who takes equal legal responsibility for a mortgage and is listed on title, meaning they are both a borrower on the contract and a registered owner of the property. In Canada, a co-signer is fully liable to the lender for the entire mortgage balance, not just a portion of it.

Co-signer vs. guarantor

Canadian lenders sometimes use the two words loosely, but the roles differ. A guarantor backs the loan and may be called on if the primary borrower defaults, yet is generally not placed on title. A co-signer is added to the mortgage and to title, so they hold a legal ownership interest in the home alongside the other borrowers. Both arrangements are assessed by the lender, but a co-signer's own finances are scrutinised in the same way as any other applicant's.

Why a co-signer helps an application

Lenders test affordability with the gross debt service and total debt service ratios and the federal mortgage stress test, which requires borrowers to qualify at a rate above their contract rate. When a borrower's income is modest, their credit file is thin, or their credit score is low, adding a co-signer with stronger income or a longer credit history can raise the mortgage amount the household qualifies for. The co-signer's own debts and obligations are counted in those calculations.

What a co-signer takes on

Being on title is not a formality. A co-signer:

Is responsible for the full payment if the other borrower stops paying.
Carries the mortgage on their own credit report, which can reduce how much they can borrow elsewhere.
Shares in the equity and any increase in value, and may need to be bought out to exit.
Can be pursued by the lender through the usual remedies, up to and including foreclosure or power of sale.

Getting out

Removing a co-signer usually means the remaining borrower must requalify on their own through a refinance or renewal, and the lender must agree to the change. Taking a name off title can also have tax and legal consequences, so it is worth getting advice from a lawyer or accountant before signing.

Frequently asked questions

Does a co-signer have to be on the title in Canada?

In this glossary's usage, yes. A co-signer is both a borrower on the mortgage contract and a registered owner on title, so they hold a legal interest in the property. That is what separates a co-signer from a guarantor, who backs the loan without being added to title. Confirm how your own lender defines the two roles in your documents.

What are the risks of being a co-signer on a mortgage?

A co-signer is liable for the entire mortgage, not a share of it. If the other borrower stops paying, the lender can pursue the co-signer, and missed payments appear on the co-signer's credit report. The mortgage also counts in the co-signer's debt ratios, which can reduce their ability to borrow for their own home or other goals.

Can a co-signer be removed from a mortgage?

Usually only with the lender's approval. The remaining borrower typically has to requalify through a refinance or renewal, showing enough income and acceptable credit on their own, and the lender may reassess the property. Removing a name from title can carry tax and legal consequences, so speak with a lawyer or accountant.