Choosing between fixed, variable or split rate structures on an investment loan shapes your cash flow, flexibility and long-term returns.
The decision matters more in South Brisbane's rental market than in many other Brisbane suburbs because vacancy rates and rental yields vary widely between the high-rise precincts along Grey Street and the character walk-ups closer to West End. A structure that suits an investor holding a two-bedroom unit in a tower with body corporate fees near $2,000 per quarter may not suit someone buying an older block closer to Kurilpa.
Fixed Investment Loans Lock in Repayments for a Set Term
A fixed rate investment loan holds your interest rate steady for an agreed period, commonly between one and five years. Your required repayments remain based on that fixed rate regardless of changes to variable interest rates during the fixed period.
For an investor, this can provide greater certainty when budgeting for the property's ongoing cash flow. For example, fixing all or part of an investment loan means you know what the interest rate will be for that portion of the debt throughout the fixed term, which can make it easier to plan around rental income and other property expenses.
The trade-off is reduced flexibility. Depending on the lender and loan product, additional repayments may be limited and features such as redraw or offset accounts may be restricted or unavailable during the fixed period. If you sell the property, refinance or repay the fixed loan before the term ends, break costs may also apply. The amount can vary depending on factors including market interest rates, the remaining fixed term and the amount being repaid.
Variable Investment Loans Offer Full Flexibility
A variable rate investment loan has an interest rate that can change over time. The Reserve Bank cash rate can influence mortgage rates, but lenders determine their own variable rates and can change them independently.
Variable structures can suit investors who value flexibility. Depending on the loan product, you may be able to make additional repayments, access redraw, use an offset account or refinance without the break costs that can apply to a fixed rate loan. The features available vary between lenders and individual loan products.
The trade-off is exposure to interest rate movements. An investor with a $500,000 variable investment loan at 6.2% on interest only repayments would pay approximately $2,583 per month in interest. If the interest rate increased by 0.5 percentage points to 6.7%, the monthly interest repayment would increase to approximately $2,792. If rental income does not cover the additional cost, the shortfall needs to be met from other income or savings.
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Split Loans Combine Both Structures
A split loan divides your investment loan into two portions: one fixed and one variable. You choose the split, commonly 50/50, but any proportion is possible.
Splitting a $600,000 investment loan into $300,000 fixed for three years and $300,000 variable gives you partial protection from rate rises while retaining flexibility on half the debt. You can make extra repayments or redraw against the variable portion, and if you decide to sell or refinance, break costs only apply to the fixed portion. The variable portion can also carry an offset account, so surplus cash reduces interest on that half of the loan.
In our experience, split structures work well for investors who want to manage risk without giving up all their options. They are particularly useful in South Brisbane where investors often hold apartments in larger complexes with sinking fund levies that can vary year to year. If an unexpected special levy is raised for building repairs, the flexibility on the variable portion allows you to access redraw or restructure that half of the loan without triggering break costs on the whole amount.
The downside is complexity. You manage two loan accounts, each with its own terms, and you need to decide how to split the loan at the outset. If rates fall, the fixed portion still holds you to the higher rate, and if rates rise, the variable portion still increases. A split structure does not eliminate risk, it spreads it.
Interest Only Terms and Tax Planning
Interest only repayments are commonly available on investment loans for an agreed period, often between one and five years. During this period, the required repayments cover the interest charged on the loan without reducing the principal balance.
Interest only repayments are lower than principal and interest repayments on the same loan amount during the interest only period, which can help investors manage cash flow. Where borrowed funds are used for an income-producing rental property, the interest may generally be tax deductible subject to how the funds are used and the investor's individual circumstances.
From the 2027–28 income year, the treatment of rental property losses will also depend on when and what type of property was acquired. Properties held before 7:30pm AEST on 12 May 2026 remain subject to the previous negative gearing arrangements. For established residential properties acquired after that time, eligible losses can generally be offset against residential property income, including eligible capital gains, with excess losses carried forward. Eligible new builds continue to have access to negative gearing against other assessable income. Independent tax advice should be obtained regarding how these rules apply to your circumstances.
APRA also classifies an interest only residential loan as non-standard where the LVR is greater than 80% and the contractual interest only period is longer than five years or has no specified end date. Individual lender policies may be more restrictive.
When the interest only period expires, the loan will generally revert to principal and interest repayments over the remaining loan term. On a $500,000 loan at 6.2%, interest only repayments would be approximately $2,583 per month. If the loan then converted to principal and interest with 25 years remaining at the same interest rate, repayments would increase to approximately $3,283 per month.
Some investors may refinance or apply for a further interest only period before the existing period expires. Any extension or refinance remains subject to a new lender assessment, including factors such as income, expenses, existing debts, the property's value and the lender's serviceability requirements.
Matching Loan Structure to Your Investment Strategy
Your choice between fixed, variable and split depends on what you are trying to achieve and how long you plan to hold the property.
If you are building a portfolio and expect to access equity within a few years to fund another purchase, a variable or split structure keeps your options open. You can refinance or restructure without penalty, and you can use offset or redraw to manage cash flow between purchases. If you are holding a single investment property for long-term income and you want repayment certainty, a fixed rate may suit, particularly if you do not need flexibility and rates are low at the time you take out the loan.
Split structures suit investors who want some certainty but are not willing to lock in the entire loan. They are also useful if you hold multiple properties and want to manage overall portfolio risk by fixing some loans and leaving others variable.
Location and property type also matter. South Brisbane apartments in large complexes often have higher body corporate fees and lower rental yields than houses or older-style units. If cash flow is tight, the certainty of a fixed rate can help. If the property generates strong rental income and you expect to use surplus funds to pay down debt or invest elsewhere, a variable structure with offset gives you more control.
Refinancing Investment Loans When Your Fixed Term Ends
A fixed rate expiry is a useful time to review your investment loan because the loan will generally move to a variable rate determined by the lender once the fixed period ends. Before expiry, you may have the option to negotiate a new rate with your existing lender, fix the loan again, move to a variable or split structure, or refinance to another lender.
Your lender will generally notify you before the fixed term expires and advise the variable rate that will apply afterwards. It can be worth comparing that rate with the lender's other available products and options from competing lenders rather than allowing the loan to roll over without review.
If the property has increased in value or the loan balance has reduced, refinancing may also provide an opportunity to access available equity for another investment, subject to borrowing capacity and lender approval. If the new loan is at or below 80% LVR, you may also be able to refinance without requiring new Lenders Mortgage Insurance, depending on the lender and circumstances.
Refinancing can take several weeks depending on the complexity of the application, valuation requirements and lender processing times. Starting the review before the fixed term expires can give you time to compare options and complete any refinance before spending an extended period on the lender's revert rate.
Ready to Review Your Investment Loan Structure?
Whether you're purchasing an investment property, approaching the end of a fixed rate period or reviewing an existing portfolio, Wealthcove can assess your current lending and compare fixed, variable and split loan options across multiple lenders based on your circumstances. Book an appointment with Liam Pahl, Finance & Mortgage Broker at Wealthcove or call Liam directly on 0452 646 192 to discuss your investment loan options.
