Why Fixed, Variable & Split Investment Loans Matter

Why Rate Structure Determines More Than Monthly Repayments

The rate structure you choose for an investment loan directly affects deductible interest, refinancing capacity, and how you respond to rate movements. A lawyer acquiring an established property under the current negative gearing rules will want maximum interest deductions in the short term, while also preserving the option to refinance or release equity as their portfolio grows. Variable, fixed, and split structures each deliver different outcomes.

Consider a lawyer purchasing an established apartment for rental purposes before 30 June 2027. Under the grandfathering provisions in the Treasury Laws Amendment (Tax Reform No. 1) Act 2026, losses from properties held at 12 May 2026 or acquired under contract before that date remain fully deductible against salary and other income. For properties acquired after that date but before 30 June 2027, full deductibility applies only until 30 June 2027. From the 2027-28 income year, losses on established properties acquired after 12 May 2026 can only offset income from other residential properties, not wage income. The interest rate structure determines how much deductible interest accrues each year and how quickly that structure can be adjusted if circumstances change.

Variable Rate Investment Loans: When Flexibility Outweighs Rate Security

A variable rate investment loan allows you to make unlimited extra repayments, access offset or redraw facilities, and refinance without break costs. The interest rate adjusts with market movements, which means deductible interest expense changes over time.

For lawyers who expect income to fluctuate or who plan to expand their portfolio within a few years, the flexibility of a variable rate structure is often more useful than locking in a rate. Variable products typically include an offset account, which reduces interest accrued on the loan while preserving access to surplus cash. The offset balance does not reduce the loan amount for the purpose of calculating the loan to value ratio under APS 112, but it does reduce the interest charged and therefore the deductible interest expense.

In our experience, lawyers with variable rate investment loans often use the offset facility to quarantine funds for deposit on their next acquisition, while continuing to reduce interest on the existing loan in the meantime. If rental income covers most of the loan repayment but leaves a shortfall, that shortfall generates a deductible loss that can, for grandfathered properties, offset other income. If the property was acquired after 12 May 2026 and is not a new build, the loss can only offset residential property income from the 2027-28 income year onward.

Fixed Rate Investment Loans: Locking In Deductible Interest and Managing Cash Flow

A fixed rate investment loan sets the interest rate for a specified term, typically one to five years. The deductible interest expense is known in advance, which makes tax planning more predictable. Fixed loans generally do not offer offset accounts or the ability to make extra repayments beyond a small annual limit, and breaking the loan before the fixed term ends may attract break costs.

When you fix an investment loan, you are accepting less flexibility in exchange for certainty. If you expect rates to rise, fixing protects your cash flow and locks in the deductible interest amount. If rates fall, you remain on the higher fixed rate unless you refinance and pay break costs. Break costs are calculated based on the difference between the fixed rate and the lender's current wholesale funding cost for the remaining fixed term, and can be substantial if rates have dropped significantly.

Fixed loans are rarely suitable for lawyers who plan to sell or refinance within the fixed period, or who may need to access equity for another purchase. However, for a lawyer holding a single investment property with stable rental income and no immediate plans to expand, a fixed rate can provide certainty around deductible interest and repayment amounts.

Split Loan Structures: Hedging Rate Risk While Retaining Access to Equity

A split loan divides the loan amount into a fixed portion and a variable portion, each with its own interest rate and features. The variable portion retains offset access, redraw, and the ability to refinance without break costs. The fixed portion provides certainty over a portion of the deductible interest.

Consider a lawyer who borrows to acquire an investment property and wants to preserve the option to release equity within two years to fund a deposit on a second property. Fixing 50 per cent of the loan for three years provides some protection against rate rises, while keeping the other 50 per cent variable allows access to an offset account and the ability to increase the variable portion if equity is released without triggering break costs on the entire loan. The fixed portion continues on its fixed rate and term, and the additional borrowing is added to the variable portion.

Split structures allow you to adjust the proportion that is fixed or variable at each refinancing or rate review. If you fix 60 per cent and leave 40 per cent variable, the variable portion continues to allow extra repayments and offset benefits, while the fixed portion anchors a portion of your deductible interest. The downside is that managing two loan accounts under one security can involve two sets of fees and more administration.

Interest Only Periods and Investment Loan Repayment Structures

Most investment loans offer an interest-only period, typically one to five years, during which only the interest is payable and the principal is not reduced. After the interest-only period expires, the loan reverts to principal and interest repayments unless you apply to extend the interest-only term.

Interest-only repayments maximise deductible interest in the early years, which is useful for properties that are negatively geared. However, under APS 112, a loan with an interest-only period exceeding five years and an LVR above 80 per cent is classified as non-standard and attracts a higher risk weight, which can affect pricing. Most lenders cap the initial interest-only period at five years for standard residential investment lending.

If you intend to refinance your investment loan to release equity or improve your rate, an interest-only period preserves your principal, which keeps your equity position unchanged and makes it easier to demonstrate serviceability for the next loan. If you switch to principal and interest repayments, the deductible interest reduces over time as the principal is paid down, and your equity increases, which may support a larger borrowing capacity if you refinance.

How APRA Serviceability Buffers and DTI Limits Affect Investment Loan Approval

Every lender assesses your capacity to service an investment loan at a rate at least 3.0 percentage points above the product rate, regardless of whether you choose fixed, variable, or split. The buffer applies to new lending only and is set by APRA. If the variable rate on offer is 6.0 per cent, you must demonstrate capacity to service the loan at 9.0 per cent or higher.

From 1 February 2026, APRA also imposed a debt-to-income limit on ADIs, restricting each lender to no more than 20 per cent of new investor loans to borrowers with a total DTI ratio of six times or greater. This applies separately to the investor lending portfolio and is measured quarterly. Non-ADI lenders are not currently subject to the DTI limit, but APRA holds powers under Part IIB of the Banking Act 1959 to extend macroprudential tools if required.

For lawyers with high salaries, the DTI limit may still constrain borrowing capacity if existing debts are substantial. The serviceability buffer and DTI limit apply regardless of your rate structure, but the repayment amount used in the assessment differs depending on whether the loan is interest-only or principal and interest, and whether the rate is fixed or variable. Lenders generally assess interest-only loans at the higher principal and interest repayment that will apply after the interest-only period ends.

LMI, LVR, and Risk Weighting Under APS 112

Investment loans are treated as higher risk under APS 112 than owner-occupied loans at the same LVR. If the LVR exceeds 80 per cent, most lenders require lenders mortgage insurance. LMI is a one-off premium paid by the borrower and is calculated based on the loan amount and LVR. It is not an ongoing cost, and it does not reduce if you pay down the loan.

Lawyers may be eligible for LMI waivers on owner-occupied lending through certain lenders, but those waivers rarely extend to investment loans. If you borrow at 90 per cent LVR for an investment property, expect to pay LMI. The premium can be capitalised into the loan amount, which increases the deductible interest, but also increases the total borrowing and may push the loan above the lender's maximum LVR once LMI is added.

Under APS 112, a residential investment loan that meets the definition of a standard loan and is secured by a registered first mortgage is subject to a risk weight determined by its LVR band. Lenders may reduce their capital requirement if the loan is covered by eligible LMI, which allows them to offer slightly lower rates on high-LVR loans with LMI in place. However, the benefit to the borrower is generally outweighed by the cost of the premium.

Tax Deductibility of Investment Loan Interest and Holding Costs

Interest on borrowings used to acquire or hold a rental property is deductible under the Income Tax Assessment Act 1997 to the extent the property is rented or genuinely available for rent. If you use an offset account, the interest saved is not deductible because it was never incurred. If you make extra repayments into a redraw facility and later redraw those funds for private purposes, the interest on the redrawn amount is not deductible. Maintaining clear separation between investment and private purposes is necessary to maximise deductions.

For properties acquired after 12 May 2026 that are not eligible new builds, losses including interest, rates, insurance, and other holding costs can only be deducted against residential property income from the 2027-28 income year onward. If you acquire an established investment property now and it runs at a loss, that loss can reduce your taxable income until 30 June 2027, and can be carried forward to offset residential property income or capital gains in later years. If the property generates a profit, the interest and holding costs reduce that profit and therefore reduce tax payable.

If you are considering debt recycling to convert non-deductible home loan debt into deductible investment debt, the interest deductibility follows the use of funds, not the security. Borrowing against your home to acquire an investment property makes the interest deductible. Borrowing against an investment property to pay down your home loan does not.

Refinancing Investment Loans and the Role of Break Costs

Refinancing a variable rate investment loan attracts no break costs, assuming no fixed rate component is in place. Refinancing a fixed rate investment loan before the end of the fixed term may result in break costs, which are payable to the lender and are not deductible as a borrowing expense in the year paid. Break costs are treated as a capital cost and may be deductible over five years or added to the cost base of the property for CGT purposes, depending on the structure.

When you refinance an investment loan, lenders reassess your serviceability and apply the current 3.0 percentage point buffer and DTI limits. If your borrowing capacity has reduced due to rate rises or changes in income, refinancing to release equity may not be possible even if your equity position supports it. Refinancing to a lower rate or to consolidate debt may still be feasible if you are not increasing the loan amount.

If part of your loan is fixed and part is variable, you can refinance the variable portion without triggering break costs, and either keep the fixed portion with the existing lender or pay it out and accept the break cost. The decision depends on the size of the break cost, the rate improvement available, and how long remains on the fixed term.

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