Avoid These 7 Property Investment Loan Mistakes

Most property investors in Mentone focus on the property itself and leave finance until the last minute.

That sequence costs money. The loan structure you choose affects your borrowing capacity, your cash flow, your tax position and the speed at which you can build a second or third property. From July next year, negative gearing will be quarantined for most new purchases, the capital gains discount will shift to indexation with a minimum tax floor, and serviceability is tested at three percentage points above the rate you actually pay. The days of defaulting to a standard variable rate and sorting out the tax later are over.

This article walks through the seven most common mistakes we see when investors come to us after already signing a contract or locking in a rate, and what to do instead.

Mistake 1: Choosing Interest-Only Without Checking the Term

Interest-only periods reduce your repayment and preserve cash flow, but the term matters more than the rate. Most lenders offer interest-only for five years on investment loans, some for up to ten if you meet specific lending criteria. When the interest-only period ends, the loan reverts to principal and interest and the repayment jumps.

Consider an investor who bought a two-bedroom unit near Mentone station with a loan of $600,000 at a variable rate. She chose a five-year interest-only term. At current variable rates for investors, her repayment sat around $2,600 per month. When the term expired, the loan converted to principal and interest over the remaining twenty years, and her repayment increased to roughly $3,700 per month. Rental income had not moved enough to cover the shortfall. She refinanced to extend interest-only, but the property valuation had softened and her equity position no longer supported a full extension without reducing the loan amount or paying Lenders Mortgage Insurance again.

If you plan to hold the property long enough to see rental growth cover principal repayments, structure the loan with a longer interest-only period from the start or plan the revert date around a salary increase or portfolio rebalance. If you intend to sell or refinance within five years, a shorter term works. Match the term to your actual hold strategy, not to what feels comfortable today.

Mistake 2: Splitting Fixed and Variable Without a Purpose

Split loans divide your balance between fixed and variable portions. The fixed portion locks a rate for a set term. The variable portion moves with the market and usually allows unlimited extra repayments and redraw without penalty.

Splitting without a specific reason adds complexity without benefit. A split works when you want partial rate certainty but also need flexibility to make lump sum repayments from bonuses, tax refunds or other income. It also works when you expect rates to fall but want insurance against a rise. A 50/50 split is common, but there is no rule. You can fix 30 per cent, 60 per cent or any proportion that suits your cash flow and risk tolerance.

We regularly see investors split their loan because the lender offered it, then never use the variable portion for extra repayments and end up paying a higher weighted average rate than they would have on a single variable loan. If you have no surplus cash to put towards the loan and you do not expect any lump sums, fixing the whole amount or staying fully variable will usually deliver a lower cost or greater flexibility. A split is a tool, not a default.

Mistake 3: Not Separating the Loan From Your Owner-Occupied Debt

Interest on borrowings used to acquire or hold rental property is deductible. Interest on borrowings for private purposes is not, regardless of what security you provide. If you refinance your home and your investment property into a single loan account, or if you use redraw from an investment loan to pay for a family holiday, you contaminate the deductibility.

Keep each loan in a separate account with a clear purpose. If you own your home with a $400,000 mortgage and you buy an investment property with a $500,000 loan, maintain two facilities. Do not cross-collateralise unless you have a specific reason and you understand the impact on future borrowing and tax. The ATO applies a purpose test, not a security test. Mixing funds in one account makes it difficult to prove what portion of the interest relates to the investment and what relates to private use.

If you have already mixed the loans, you can refinance into separate splits, but you may need a valuation and you will pay establishment fees again. It is easier to structure correctly from the beginning.

Mistake 4: Ignoring Debt-to-Income Limits When Planning a Second Property

From February this year, lenders can only write 20 per cent of new investor loans at a debt-to-income ratio of six times or more. That cap is separate from the owner-occupier cap, but it still restricts how much you can borrow if your income has not grown in line with your debt.

Debt-to-income is calculated as total debt across all properties divided by your gross annual income. If you earn $120,000 and you already have $500,000 in investment debt and $300,000 in owner-occupied debt, your DTI sits at 6.7. Most lenders will either decline a new investor loan or require you to reduce existing debt, increase your income or wait until a greater portion of their portfolio is available under the 20 per cent allowance.

The cap does not apply to finance for new builds, so if you are planning a second investment property and your DTI is already above six, purchasing a newly constructed dwelling or building on vacant land gives you a path that avoids the restriction. It also means the property remains eligible for unrestricted negative gearing and the 50 per cent capital gains discount under the new tax rules. That combination can make a new build more attractive than an established property, even if the purchase price sits slightly higher.

Mistake 5: Underestimating How Serviceability is Tested

Lenders assess your ability to repay at a rate three percentage points above the product rate, not at the actual rate you will pay. If you are applying for a variable rate loan at 6.3 per cent, the lender tests your income and expenses as though the rate were 9.3 per cent. That buffer is set by APRA and applies to all lenders.

Rental income is included in the serviceability calculation, but it is shaded. Most lenders apply 80 per cent of the assessed rent to allow for vacancy, management fees and maintenance. Some lenders use 75 per cent. If the property rents for $600 per week, the lender will credit you with $480 per week in income, or around $2,080 per month. That income is then tested against the buffered interest rate to determine whether you can afford both the new loan and your existing commitments.

Mentone's rental vacancy rate has sat below 2 per cent for the past two years, but lenders do not adjust the shading based on local conditions. The 80 per cent figure is national and does not move. If you rely on full rental income to cover the loan and your other expenses, you may find the loan is declined even though the actual repayment is comfortably covered by rent. Plan your deposit and your borrowing amount with the shaded rental income in mind, not the advertised rent.

Mistake 6: Paying Lenders Mortgage Insurance Without Exploring Alternatives

Lenders Mortgage Insurance is charged when your loan-to-value ratio exceeds 80 per cent. The premium is calculated as a percentage of the loan amount and added to the balance or paid upfront. On a $600,000 loan at 90 per cent LVR, the premium typically falls between $15,000 and $25,000, depending on the lender and your deposit source.

LMI protects the lender, not you. It does not reduce your repayment or give you any additional rights. In some cases it makes sense to pay it, particularly if property prices are rising quickly and waiting another year to save a larger deposit would cost more in price growth than the premium. In other cases, using equity from your existing home, bringing in a guarantor, or waiting to reach 80 per cent LVR will save you the cost without delaying the purchase.

If you are close to 80 per cent, run the numbers both ways. A borrower with a 15 per cent deposit might find that waiting six months to reach 20 per cent saves $20,000 in LMI and only costs $10,000 in foregone rental income and potential price movement. Alternatively, if you already own property in Mentone or nearby with sufficient equity, refinancing to release that equity can fund the full deposit without LMI. The choice depends on your timeline, your equity position and your income.

Mistake 7: Not Planning for the Negative Gearing Quarantine in July Next Year

From 1 July 2027, net rental losses on residential investment properties purchased on or after 7:30pm AEST on 12 May 2026 can only be offset against other residential rental income or carried forward. You cannot offset the loss against salary, wages or other income. Properties you already own and properties under contract before that date are grandfathered and continue under the current rules until you sell.

If you bought an investment property in Mentone between mid-May this year and June next year, you have a transition period. You can still negatively gear under the old rules until 30 June 2027, but after that date the quarantine applies. If you are planning to buy in the next twelve months and the property will run at a loss, you need to model your cash flow without the tax refund from negative gearing. That changes the amount of surplus income you need to hold the property and may change the type of property that works for you.

Eligible new builds remain exempt. If the property is constructed on previously vacant land or replaces an existing dwelling and increases the total number of dwellings, you can still offset losses against other income. A knock-down rebuild that replaces one house with one house does not qualify. A subdivision that replaces one house with two townhouses does. If your investment strategy relies on negative gearing, purchasing a new build between now and when you are ready to buy gives you access to the old rules indefinitely, assuming the property has not been occupied for more than twelve months before you buy it.

The capital gains tax changes also take effect in July next year. The 50 per cent discount is replaced with cost base indexation and a 30 per cent minimum tax rate on real gains. New builds retain the option to elect the 50 per cent discount instead. The tax treatment alone may shift the relative value of new versus established stock for investors with a hold period longer than ten years. Speak to your accountant and your broker together before you sign anything.

Getting your investment loan structure right means understanding how the loan works with your income, your tax position, your equity and your next purchase. Mentone has seen steady capital growth and tight rental conditions for several years, but the property itself is only half the equation. The loan you choose affects your cash flow, your ability to build a portfolio and the tax you pay when you sell.

Call one of our team or book an appointment at a time that works for you. We work with investors across Bayside and we have access to investment loan options from lenders that suit different structures, different deposit levels and different strategies.

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