A co-signer takes on 100% of the debt, not half of it. If the borrower stops paying, the lender pursues the co-signer for the entire balance – not their share, the whole mortgage.
That is the fact worth understanding before anything else on this page.
Co-signer, co-borrower, guarantor
Three arrangements, and lenders use the words loosely.
| On title? | On the mortgage? | Liability | |
|---|---|---|---|
| Co-borrower | Yes | Yes | Full, from day one |
| Co-signer | Usually yes | Yes | Full, from day one |
| Guarantor | No | Guarantees the debt | Full, but usually only after default |
A co-borrower is a joint owner – typically a spouse or partner buying together, with an interest in the property.
A co-signer strengthens the application. Most lenders require them on title as well, precisely because someone fully liable for a debt should have a legal interest in the asset securing it.
A guarantor backs the loan without owning the property. Fewer lenders permit it, and it is generally used where a parent wants to help without going on title.
Does a co-signer have to be on title in Canada?
Usually yes. Most Canadian lenders require it, and many will not proceed otherwise.
Some lenders accept a guarantor structure that keeps the helper off title. It is worth asking, because being on title has consequences the family often has not considered – which are covered below.
Why lenders ask for a co-signer
- Income is too low for the debt service ratios on the target property
- Credit history is thin – new to Canada, young, or few accounts
- Credit score is bruised by past problems
- Self-employed with income that is hard to document
- Existing debt pushes the TDS ratio past the limit
A co-signer solves the first four. It does not solve the last one cleanly – the co-signer’s own debts come into the calculation too, and a co-signer carrying their own mortgage and car loan may add less capacity than expected.
Requirements to be a co-signer
- Strong credit – generally 680 or higher, and lenders look at depth of history, not only the score
- Verifiable income sufficient to carry both their own obligations and this mortgage
- Debt ratios that still fit with the new mortgage included
- Canadian residency, with standard identification and income documents
- A relationship to the borrower – most lenders want a family connection and will question an arm’s-length co-signer
The risks, plainly
Your credit reports the full mortgage. Not a portion. When you apply for anything else – your own mortgage, a car loan, a line of credit – that full balance counts against your ratios. Co-signing for your child can mean you cannot refinance your own home.
One missed payment damages your score, even if you never knew about it. Ask to be set up for statement access so you can see the account.
You cannot walk away. Not if the relationship ends, not if you move, not if the borrower’s circumstances change. Release requires the lender’s approval.
If you are on title, the property is your asset – with all that implies. It may be exposed in your own divorce or to your creditors, and it can affect the principal residence exemption on your own home when you sell.
Capital gains exposure. If you own your own home and are on title to a second property, part of the gain on that second property may be taxable when it sells. On a Toronto property held for a decade, that can be a substantial and entirely unexpected bill. Speak to an accountant before signing, not after.
Does co-signing affect first-time home buyer status?
For the borrower, no. Having a co-signer does not change their first-time buyer status or their eligibility for the land transfer tax rebate, the Home Buyers’ Plan, or the FHSA.
For the co-signer, it can. In Ontario, the land transfer tax rebate is reduced in proportion to the interest acquired by someone who is not a first-time buyer. A parent going on title with a child can shrink the child’s rebate – sometimes to half.
This is avoidable. Structuring the parent as a guarantor rather than an owner, or taking a nominal 1% interest, can preserve the rebate. Raise it with your broker and lawyer before the offer, because it cannot be fixed afterwards.
Can a first-time buyer have a co-borrower?
Yes. Both can be first-time buyers, in which case both rebates apply. Where one is not, the rebate is prorated as above.
How to protect yourself
- See the numbers. The full application, the payment, the ratios. If the borrower cannot comfortably carry it, co-signing does not fix that – it transfers it to you.
- Get statement access so you learn about a missed payment from the lender, not from your credit report a year later.
- Agree an exit in writing – a target date to refinance, and what happens if it slips.
- Consider life and disability insurance on the borrower, so a death or illness does not land the whole mortgage on you.
- Get your own advice. A lawyer for the title implications, an accountant for the tax.
Removing a co-signer later
Only two ways, and both require the lender:
Refinance. The borrower applies alone. If they now qualify – more income, more equity, better credit – the old mortgage is paid out and you are released. Watch for a prepayment penalty if the term is not up.
At renewal. Some lenders will renew in one name if the borrower qualifies. Ask well before the renewal date; it is much cheaper than refinancing mid-term.
There is no route that does not involve the borrower qualifying alone. Plan for a realistic timeline – usually two to five years of income growth or equity.
Frequently asked questions
What does it mean to cosign a mortgage? You become fully liable for the debt – 100% of it, not half. If the borrower stops paying, the lender pursues you for the entire balance.
What is the downside of cosigning a mortgage? The full mortgage appears on your credit report and counts against your own debt ratios, which can stop you refinancing or buying. One missed payment damages your score. You cannot walk away, and if you are on title the property is exposed to your own divorce and creditors.
Is cosigning ever a good idea? It works where the only gap is credit history or documented income – a new graduate, a newcomer to Canada, or a self-employed borrower with strong deposits. Ask to see the actual payment against the actual budget before agreeing, and set a target date for refinancing you out.
What requirements does a cosigner need? Generally a credit score of 680 or higher with real depth of history, verifiable income sufficient to carry both their own obligations and this mortgage, debt ratios that still fit, Canadian residency, and usually a family relationship to the borrower.
Does a cosigner have to be on title in Canada? Most lenders require it. Some accept a guarantor structure that keeps the helper off title – worth asking, because being on title carries tax and land transfer tax rebate consequences most families never consider.
Can you be a borrower but not on title? That is essentially the guarantor arrangement. Fewer lenders permit it, and the guarantor is still liable for the debt.
Can my parent cosign my mortgage? Yes, and it is the most common arrangement. Check first whether it reduces your Ontario land transfer tax rebate – a parent who is not a first-time buyer going on title can shrink your rebate, sometimes by half. It is avoidable if raised before the offer.
What if nobody will cosign for me? Options remain: a larger down payment, a 30-year amortization, an alternative lender with more flexible income policies, or buying at a lower price point and refinancing later. A broker with access to 35+ lenders will find them faster than one bank will.
Talk it through before you sign
Turkin Mortgage works with over 35 lenders, and their co-signer and guarantor policies differ widely – including which ones will keep a parent off title.
We will show both parties exactly what they are taking on, and whether there is a structure that avoids it entirely.
No cost, no obligation, complete confidentiality.
General information as of August 2026. Get independent legal and tax advice before co-signing.
