Guarantor Home Loans Explained: How a Family Member Can Help You Buy Without a Full Deposit

In Sydney, where saving a 20% deposit can take a decade or more, guarantor home loans have become one of the most practical paths into the market for first home buyers with supportive family. But they're also one of the most misunderstood — particularly around the risks the guarantor takes on. Here's a clear-eyed guide to how they work, who they're right for, and what both parties need to know before signing anything.

What Is a Guarantor Home Loan?

A guarantor home loan is a standard home loan with an added layer of security — a family member (the guarantor) offers equity in their own property to support your borrowing.

The guarantor doesn't give you any money. They don't go on your mortgage. They simply allow the lender to use their home as additional security, which reduces your effective loan-to-value ratio (LVR) and eliminates the need for Lenders Mortgage Insurance (LMI).

In practical terms: if you have a 5% deposit but a parent with equity in their home agrees to guarantee part of your loan, the bank treats the loan as if your combined security covers 20% — and you buy without LMI.

All four major banks — CBA, ANZ, Westpac, and NAB — offer guarantor loans, as do most non-major lenders. The product goes by different names depending on the bank:

How Does It Work? A Worked Example

Here's a practical example using a $750,000 purchase:

Your loan is still $712,500 — you borrowed no less. But your parent's property provides the additional security that removes the LMI requirement. You make all the repayments. Your parent has no ongoing obligations unless you default.

Limited vs Full Guarantee

Most modern guarantor loans use a limited guarantee — the guarantor's liability is capped at a specific amount. Typically this is the difference between your deposit and 20% of the purchase price. This is the structure almost all lenders use today.

A full guarantee (where the guarantor backs the entire loan amount) is rare and carries significantly higher risk. Most brokers and lenders will actively discourage it.

Who Can Be a Guarantor?

Most lenders restrict guarantors to immediate family members:

• Parents (most common)
• Grandparents
• Siblings
• In some cases: step-parents, de facto partners' parents (lender-dependent), or adult children guaranteeing a parent's loan

The guarantor must:

The guarantor does not need to be an Australian citizen or permanent resident, but the property used as security must generally be in Australia.

How Much Equity Does the Guarantor Need?

The guarantor needs enough equity to cover the gap between your deposit and 20% of the purchase price — plus the lender needs their own property to remain comfortably below 80% LVR after the guarantee is added.

What Are the Risks for the Guarantor?

This is the part that deserves the most attention. Guarantors often underestimate what they're agreeing to.

1. Their home is security for your debt

If you miss repayments and the lender can't recover the full debt from the sale of your property, they can pursue the guarantor for the guaranteed amount. In the worst case, the guarantor's home could be sold to cover the shortfall.

2. Their borrowing capacity is reduced

While the guarantee is in place, lenders treat it as a contingent liability when assessing the guarantor's own finances. This reduces their borrowing power — relevant if they're planning to refinance, invest, or purchase another property.

3. The guarantee may last longer than expected

If your property doesn't grow in value quickly, or if you don't make extra repayments, the LVR may take years to drop to 80% — meaning the guarantee stays in place longer than anticipated.

4. Unlimited guarantees carry unlimited risk

This is why a limited guarantee is so important. With an unlimited guarantee, the guarantor is exposed to the entire loan — principal, interest, and lender's costs. Always confirm the guarantee is capped at a specific dollar amount before proceeding.

How Is the Guarantee Released?

The guarantee is released when your LVR drops to 80% or below, based on your outstanding loan balance and the current value of your property. This happens through:

• Regular repayments reducing the loan balance
• Property value growth increasing your equity
• A combination of both, or a lump-sum payment

To release the guarantee, you request a lender valuation of your property and formally apply for the release. The process is straightforward once the numbers stack up.

In a rising market, growth alone can do a significant portion of the work — though in the current rate environment, with softer price growth in parts of Sydney, 3–5 years is a more realistic expectation.

Guarantor Loan vs Other Options

Before deciding on a guarantor loan, it's worth comparing the alternatives:

For buyers with a supportive family and a parent with property equity, a guarantor loan is often the cleanest outcome — no government co-ownership, no LMI, no income or place caps. The First Home Guarantee is better where eligible, since no family member takes on any risk. For purchases above the $1.5m Sydney metro cap, a guarantor loan becomes the main LMI-free alternative.

What Does the Process Look Like?

1. Speak to a mortgage broker — they'll assess your borrowing capacity, your deposit, and whether a guarantor arrangement is suitable
2. Identify a willing family member with sufficient equity
3. Both the borrower and guarantor apply together — the lender assesses both properties
4. The guarantor obtains independent legal advice (required by virtually all lenders)
5. Loan is approved and settled — a mortgage is registered against your property and a separate security is registered against the guarantor's property
6. You make repayments as normal — the guarantor has no ongoing obligations unless you default
7. Once your LVR reaches 80%, apply to release the guarantee

The Conversation to Have First

Before approaching a lender, the most important conversation is the one between borrower and guarantor. Both parties should understand:

A guarantor loan is built on family trust. It works well when both parties go in with clear eyes. It can damage relationships when it doesn't go as planned — and it does occasionally go wrong. Having that honest conversation before signing is the most important step in the whole process.

Written by Amit Narang, Mortgage Broker | Credit Representative 558902 of Outsource Financial Pty Ltd (ACL 384324)

Sources: MoneySmart (moneysmart.gov.au); Australian Banking Association — guarantor loan policy guidance; Commonwealth Bank Family Security Guarantee product disclosure; ANZ Family Pledge product disclosure; Westpac Family Security Guarantee product disclosure; NAB Family Equity Loan product disclosure; MFAA broker guidance on guarantor arrangements.