Fixed Rate Investment Loans: 5 Facts ADF Investors Need

Fixed Rate Investment Loans Lock In Your Borrowing Cost

A fixed rate investment loan holds your interest rate at the same level for a set period, typically one to five years. You pay the same amount each repayment cycle regardless of market rate movements during that period. Variable rate investment loans move up or down when lenders adjust rates.

For ADF members posted frequently or deployed for extended periods, the predictability matters. You know what the property will cost to hold, you can calculate the tax deduction on interest accurately, and you remove one variable from cashflow planning. If you're posted to Singleton or Puckapunyal for two years and holding a rental property in another state, a fixed rate that matches your posting timeline removes the need to monitor rate announcements or refinance mid-posting.

Fixed rates typically sit higher than variable rates at the time you lock them in. The premium reflects the lender's cost of hedging and the fact you're transferring rate risk to them. Whether that premium is worth paying depends on your deployment schedule, rental yield, and whether you expect rates to rise or fall during the fixed period.

Most lenders limit flexibility during a fixed term. You may face restrictions on extra repayments, usually capped at $10,000 to $30,000 per year depending on the product. If you sell the property or refinance before the fixed term ends, break costs may apply. Those costs reflect the lender's loss when they've hedged your loan at one rate and must now unwind that position at a different rate.

How the Serviceability Buffer Affects What You Can Borrow

Every lender assesses your ability to service an investment loan at a rate at least 3.0 percentage points above the product rate you'll actually pay. If you're applying for a fixed rate investment loan at 6.2 per cent, the lender tests whether you can afford repayments at 9.2 per cent or higher. The 3.0 percentage point buffer has been in place since October 2021 and applies to all new loans from banks, credit unions and building societies regulated by APRA.

The buffer applies whether you choose a fixed rate, variable rate, interest-only or principal-and-interest structure. It's a prudential requirement, not a product feature. For ADF members with stable income and structured allowances, the buffer calculation is usually straightforward. Lenders generally accept base salary and most ongoing allowances when calculating serviceability, though treatment of field allowance and deployment income varies between lenders.

The DTI limit introduced in February 2026 adds a second constraint. Lenders can extend no more than 20 per cent of their new investor loans to borrowers with a total debt-to-income ratio of six times or greater. If your total borrowings across all loans, including any existing home loan, exceed six times your gross income, you may fall into the portion of the lender's book subject to rationing. This affects high-LVR borrowers or those purchasing at the top end of their capacity more than it affects borrowers with substantial equity or deposits.

Interest-Only Repayments and Capital Growth Strategy

An interest-only investment loan requires you to pay interest each month without reducing the principal. The loan balance stays the same throughout the interest-only period, which is typically one to five years. At the end of that period, the loan either reverts to principal-and-interest repayments or you can request a further interest-only term if the lender's policy and your circumstances allow it.

Interest-only repayments are lower than principal-and-interest repayments on the same loan. This improves cashflow and may increase the amount you can borrow under serviceability tests, though lenders apply stricter serviceability buffers to interest-only loans. For an ADF member holding a property primarily for capital growth and tax deductions, the interest-only structure maximises the deductible interest component and frees up cashflow for other investments or to cover vacancy periods.

Rental income offsets part of the holding cost. Lenders generally include 80 per cent of forecast rental income when calculating serviceability, to account for vacancy, maintenance and management costs. If the rental property is negatively geared, meaning your deductible expenses including interest exceed your rental income, the loss can be offset against your salary under current negative gearing rules. That reduces your taxable income and increases your after-tax cashflow.

From the 2027-28 income year, losses on established investment properties acquired after 12 May 2026 can only be deducted against income from other residential properties, not against salary. Properties acquired before that date, including those under contract on 12 May 2026, retain full negative gearing treatment indefinitely. New builds remain fully negatively geared regardless of purchase date. If you're considering an established property as an investment opportunity, the distinction affects after-tax holding costs and may tilt the comparison towards new builds or properties acquired before the cut-off.

When Break Costs Apply on Fixed Rate Investment Loans

Break costs are charged when you exit a fixed rate loan before the fixed term ends. They're calculated based on the difference between the rate you locked in and the rate the lender can now achieve when it reinvests the funds in the wholesale funding market. If rates have fallen since you fixed, the lender incurs a loss and passes that cost to you. If rates have risen, break costs are usually minimal or zero.

Consider an ADF investor who fixed a property loan at 5.8 per cent for three years in early 2025. If they're posted overseas in mid-2026 and decide to sell the property, they would exit the loan roughly 18 months into the fixed term. If wholesale rates have dropped to 4.5 per cent in the interim, the lender will charge a break cost reflecting the lost interest income over the remaining 18 months. The cost can reach tens of thousands of dollars on a loan in the $400,000 to $600,000 range, depending on the rate gap and remaining term.

Some lenders offer portability, allowing you to transfer the fixed rate loan to a new property without break costs, though fees and conditions apply. Others allow partial rate unlocking or switching part of the loan to variable while keeping the remainder fixed. If you're likely to be posted or deployed during the fixed period, variable rate or shorter fixed terms carry less exit risk. The investment loan refinancing page covers options when your circumstances change mid-term.

Why Lenders Treat Investment Loans Differently to Owner-Occupied Loans

Investment loans attract higher interest rates and stricter serviceability criteria than owner-occupied loans because they carry higher credit risk. Under APRA's prudential standards, lenders must assign higher risk weights to investment property loans when calculating their capital requirements. This increases the cost of funding those loans, which flows through to the rate you pay.

An investment property generates rental income, but that income depends on an ongoing tenant and local market conditions. If the property sits vacant for several months, or if rental demand softens, the borrower must cover the full loan repayment from other sources. Owner-occupiers typically prioritise mortgage repayments over other expenses because the property is their home. Investors may choose to sell or default if the holding cost becomes unaffordable.

Lenders also apply different LVR limits. Most will lend up to 90 per cent LVR on an investment property, compared to 95 per cent for owner-occupiers under some schemes. ADF members have access to low deposit loans and LMI waivers through certain lenders, which can reduce upfront costs. LMI on an investment loan is calculated at a higher rate than on an owner-occupied loan at the same LVR. The premium is a one-off cost, usually capitalised into the loan, and is not tax deductible because it relates to the loan arrangement rather than the income-producing use of the property.

Stamp duty on investment property purchases is payable at the standard rate in all states and territories. First home buyer concessions and discounts don't apply. The stamp duty is added to the property's cost base for CGT purposes, reducing your taxable gain when you eventually sell.

What Changed for Investment Property Tax Treatment in 2026

The Treasury Laws Amendment (Tax Reform No. 1) Act 2026 received royal assent on 26 June 2026 and introduced two changes affecting residential investment property acquired after 7:30pm AEST on 12 May 2026. Established properties acquired after that date can only deduct rental losses against other residential property income from the 2027-28 income year onwards. New builds remain fully negatively geared. Properties acquired on or before 12 May 2026, including those under contract awaiting settlement at that date and time, retain full negative gearing indefinitely.

From 1 July 2027, the 50 per cent CGT discount is replaced by cost base indexation and a 30 per cent minimum tax rate on real capital gains for affected properties. You index the cost base using CPI and pay tax only on above-inflation gains. For properties owned before 1 July 2027 and sold after that date, gains are split. The portion accruing before 1 July 2027 is taxed under the old 50 per cent discount rules. The portion accruing after 1 July 2027 is taxed under the new indexed system. New builds qualify for both the 50 per cent discount and the indexed treatment, and you can choose whichever delivers the lower tax outcome when you sell.

Defence members holding investment property acquired before mid-May 2026 are unaffected by the negative gearing changes. Interest on the loan remains fully deductible against salary. Those purchasing established property after that date should model the after-tax cashflow using losses quarantined to residential property income only. If you don't have other residential property income to offset the loss, those losses carry forward and reduce tax on future rental income or capital gains from residential property. The change doesn't affect your ability to borrow or the serviceability calculation, but it increases the after-tax holding cost and may shift the balance towards new builds or other asset classes.

If you're comparing fixed rate options at expiry on an existing investment loan, the grandfathering rules mean you retain full negative gearing even if you refinance, provided the property was acquired before the 12 May 2026 cut-off. Refinancing doesn't reset the acquisition date.

Call one of our team or book an appointment at a time that works for you. We'll run the numbers on your posting timeline, compare fixed and variable structures, and confirm how the 2026 tax changes apply to your situation.

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