Using Equity to Buy an Investment Property (2026): The Arithmetic, the Release Structures and the Risks the Brochure Leaves Out

Using Equity to Buy an Investment Property (2026): The Arithmetic, the Release Structures and the Risks the Brochure Leaves Out

Most investors never save a second deposit. They release one from the home they already own.

Releasing equity from a commercial property instead? That is its own guide. This one is about the most common move in Australian property investing: using the equity in the home you live in to fund the deposit on an investment property.

What usable equity actually is

The arithmetic takes one line. Multiply the current value of your home by 0.80, then subtract your current loan balance. The result is your usable equity at the 80 per cent line. Some lenders will go beyond it with LMI added to the cost, but 80 per cent is the working assumption that keeps the release clean, and it is the same line our plain English refinancing guide uses for every release scenario.

Note the gap between the two equity numbers. This owner holds $340,000 of equity in the ordinary sense, value minus loan, but around $160,000 of usable equity. The difference is the 80 per cent line.

The number that moves this calculation is not the loan balance you chip away at each month. It is the valuation. A lender works from a bank valuation, not from what a neighbouring house listed for, and bank valuations tend to run conservative. Two lenders can also return two different valuations on the same home in the same week, which means usable equity is not one fixed number: it is a number per lender, and it is one of the quiet reasons the same borrower can be released $30,000 more at one institution than another. That is worth knowing before you accept the first figure you are given.

From equity to a purchase: how far it stretches

Usable equity does not buy the investment property. It funds the deposit and costs, and a new investment loan carries the rest. So the practical question is not how much equity you have, but how much purchase your equity supports.

Work it backwards from the deposit. A 20 per cent deposit on the new purchase keeps the investment loan itself at 80 per cent and out of LMI territory. One fifth of the price as deposit means that, before costs, each dollar of usable equity supports five dollars of purchase price. Stamp duty and purchase costs then pull that back, and because those costs vary meaningfully by state, the honest version is a band rather than a formula: usable equity covering a 20 per cent deposit plus costs supports a purchase of around four to five times its size. Treat that as a rule of thumb for sizing your search, not as a lender formula.

In the illustration, $160,000 of usable equity puts a purchase somewhere around $640,000 to $700,000 inside the rule of thumb once state costs are paid, and closer to $800,000 only if costs were somehow zero, which they never are. What counts as a deposit, and where the LMI thresholds actually sit, is covered in our investment property deposit guide.

One honest caveat belongs here, because the brochures skip it. Equity answers the deposit question only. The loan itself is answered by income. Releasing equity does not create a dollar of income, and both the released loan and the new investment loan must pass serviceability testing on what you earn, with lenders counting only a portion of the expected rent. Plenty of homeowners hold six figures of usable equity that their income cannot yet carry. The full purchase sequence, borrowing power first and property last, is in our step by step investment property guide.

The two ways lenders release equity

Once the numbers work, the release itself happens in one of two ways. The difference looks administrative and is not.

A loan increase on your existing mortgage

The lender reassesses your position, values the home, and increases your current loan, sometimes called a top up. One loan, one repayment, one set of statements. The drawback is that the borrowing for your home and the borrowing for the investment now live in the same account, which blurs the line between the two purposes. That blur matters at tax time, and it matters again every time you try to work out what the investment actually costs you.

A separate loan split or facility

The lender keeps your original home loan untouched and opens a second, separate loan secured by the home, sized to the deposit and costs for the investment purchase. The investment borrowing now has its own balance, its own statements and its own clearly documented purpose from day one.

Interest deductibility follows the purpose of the borrowed funds, not the property that secures them, which is why the separate split is usually the cleaner structure at tax time. The purpose of funds detail, including the ATO guidance it rests on, is in our guide to refinancing an investment property loan, and how any of it applies to your return is a conversation for your accountant, not a broker and not a blog.

Cross collateralisation: the structure to question

Here is the part of the structure conversation that rarely makes it into a lender brochure, because the structure in question tends to suit the lender.

Cross collateralisation means one lender holds both properties, your home and the new investment, as security for both loans. It often happens by default rather than by decision: you release equity and buy through the same lender, the paperwork bundles the securities together, and nobody flags it because it is the path of least resistance on the day.

The alternative is two stand alone loans: the equity release secured by your home, and the investment loan secured by the investment property, with no overlap. Many brokers, including this one, structure loans separately wherever the file allows it, for reasons that only show up later:

• Selling gets simpler. With stand alone loans, selling the investment involves the investment loan. Under cross collateralisation, the lender can require a revaluation of the whole position and may direct sale proceeds toward the remaining loan before releasing anything.
• Refinancing stays possible one property at a time. Separate loans can move to separate lenders whenever one stops being competitive. Crossed loans move together or not at all.
• The next release is easier. Future usable equity can be assessed against one property rather than a combined position that one soft valuation can drag down.
• No single lender controls both titles. Which is the quiet point underneath the other three.

Cross collateralisation is not always wrong, and there are files where it is the only workable path. But it should be a decision you make, not a default you discover in the loan documents afterwards. If a proposed structure crosses the securities, the question to ask is simple: what does this give me that two stand alone loans do not?

The risks nobody puts in the brochure

Used well, equity release is how most Australian portfolios actually start. Used casually, it concentrates risk in the one asset your family lives in. Both things are true, and an honest guide holds them together.

• Two loans now lean on the family home. The released equity is not found money. It is new borrowing secured by your house, so a failed investment does not stay quarantined on the investment side of the ledger.
• Thin buffers meet falling markets. Borrowing near the 80 per cent line on both properties works while values hold. If they fall, the combined position can move toward or past the value of the securities. What that looks like, and the calm playbook if it happens, is in our negative equity guide.
• Vacancy does not pause the repayments. Both loans keep running whether or not a tenant is paying rent. A cash buffer covering several months of both repayments is not conservative decoration; it is what lets you hold through a bad quarter instead of selling into it.
• Everything is now the same asset class. Home and investment rise and fall on the same market cycle. That is not a reason to avoid property; it is a reason to borrow below your maximum rather than at it.

None of this argues against using equity. It argues for the version where the structure is deliberate, the buffer is real and the borrowing sits comfortably below the ceiling a lender would technically approve.

Refinance first?

In practice, equity release is often not a stand alone transaction. It happens at refinance time, and there is a logic to bundling them: the release requires a fresh valuation and a full reassessment anyway, which is exactly the work a refinance does, so one process can reprice the existing loan and set up the investment split in the same pass.

The sequencing matters more in a soft market. A valuation locked in earlier in a downturn generally supports more usable equity than one taken after further falls, which is an argument for establishing the release before you need it rather than the week you find a property. If the existing loan has drifted uncompetitive, the case compounds. The mechanics of the whole move are in refinancing in plain English, and the investment specific version, including the purpose of funds rules, is in the investment refinance guide.

Frequently asked questions

How much equity do I need to buy an investment property?

Enough usable equity to cover the deposit and purchase costs on the new property. At a 20 per cent deposit plus costs, that means usable equity of roughly a quarter of the intended purchase price. Smaller amounts can still work where the new loan goes above 80 per cent with Lenders Mortgage Insurance included in the arithmetic.

What is the difference between equity and usable equity?

Equity is the current value of the property minus the loan balance. Usable equity is the portion a lender will generally release: the amount that keeps total borrowing within 80 per cent of the current value. As an illustration, a home worth $900,000 with a $560,000 loan holds $340,000 of equity but around $160,000 of usable equity.

Can I buy an investment property with no cash deposit?

Often, yes. Where usable equity covers the deposit and the purchase costs, the entire purchase can be funded by borrowing: the released equity plus the new investment loan. No cash changes the arithmetic, not the assessment. Both loans still have to pass serviceability testing on your income, with lenders counting only a portion of the expected rent.

Should I top up my existing loan or open a separate split?

A separate split keeps the investment borrowing apart from the original home loan, which keeps the purpose of each loan clear for tax and keeps the running cost of the investment visible. A top up mixes both purposes in one account. Many brokers favour the split for those reasons, and your accountant is the right person to confirm what suits your position.

What is cross collateralisation and should I avoid it?

Cross collateralisation is one lender holding both your home and the investment property as security for both loans. It can limit your options when you later want to sell, refinance or release more equity, because every change is assessed against the combined position. Stand alone loans against each property preserve flexibility, which is why many brokers prefer them. Ask the question before signing, not after.

What happens if property values fall after I release equity?

Borrowing near the 80 per cent line on two properties leaves thin buffers, and a fall in values can push the combined position toward or past the value of the securities. The loans keep running regardless. The practical protections are borrowing below the approved maximum, holding a cash buffer for vacancies and rate movement, and measuring the investment in years rather than months.

The honest summary

Using equity to buy an investment property is the most ordinary advanced move in Australian lending: a subtraction, a rule of thumb and a structure decision. The subtraction is 80 per cent of value minus the loan. The rule of thumb is four to five times the result in purchase price, state costs deciding where in the band you land. The structure decision, split versus top up and stand alone versus crossed, is where the long term risk actually lives, and it is the part a brochure will not argue with you about. Get the valuation current, keep the loans clean, hold a real buffer, and the deposit for the next property is probably already sitting in the walls of this one.