The rate structure you choose for an investment loan affects how much control you have over repayments, how quickly you can reduce debt, and whether you can adapt your loan as your portfolio grows.
A fixed rate locks in your interest cost for a set period, usually one to five years. A variable rate moves with the market and typically offers more flexibility in how you use the loan. A split loan divides your borrowing between the two, giving you partial certainty and partial flexibility. The choice depends on how you plan to use the property, whether you expect to make extra repayments, and how much exposure to rate movements you're willing to accept.
Fixed Rate Investment Loans: When Certainty Matters
A fixed rate gives you a set interest cost for the fixed period, so your repayments stay the same regardless of what happens in the broader market. This removes uncertainty around your cash flow and makes it easier to forecast whether the property will be positively or negatively geared over that period.
Consider a buyer purchasing a two-bedroom apartment in Brunswick as a long-term hold. They expect modest rental growth and plan to keep the property interest-only for the first five years while they build equity in their owner-occupied home. A five-year fixed rate at current investor rates gives them predictable repayments and removes the risk of rate increases eroding their cash flow during that holding period. They know exactly what the property will cost them each year, which makes tax planning more straightforward.
The trade-off is flexibility. Most fixed rate products limit extra repayments to around $10,000 per year, restrict access to offset accounts, and charge break costs if you exit the loan early. If you sell the property, refinance, or want to access equity before the fixed term ends, those costs can be significant. Fixed rates also tend to price in the market's expectation of future rate movements, so you're not always locking in at the lowest possible cost.
Variable Rate Investment Loans: Flexibility for Active Investors
A variable rate moves in line with market conditions and the lender's pricing decisions. Your repayments will change over time, but you gain access to features that let you manage the loan more actively.
Most variable rate investment loans allow unlimited extra repayments, full offset account access, and the ability to redraw funds if your circumstances change. If you're building a portfolio and expect to use equity from one property to fund deposits on others, a variable rate gives you the flexibility to access that equity without penalty. You can also refinance or sell without worrying about break costs.
The downside is exposure to rate movements. If rates rise, your repayments increase and your cash flow tightens. If the property is negatively geared and you're relying on rental income to cover part of the shortfall, a rate increase can put pressure on your budget. That risk is manageable if you have a buffer in your offset or other liquid savings, but it requires more active monitoring than a fixed rate.
Variable rates also tend to offer better discounts for investors with larger deposits or those consolidating multiple loans with one lender. If you're an experienced investor with a low loan to value ratio, the rate difference between fixed and variable can be significant enough to offset the additional risk.
Split Loans: Balancing Certainty and Control
A split loan divides your borrowing into a fixed portion and a variable portion. You choose the split, usually in increments of 10%, and each portion operates independently with its own rate and features.
In our experience, a 50/50 split works for investors who want some protection from rate rises but still need access to offset accounts and the ability to make extra repayments. The fixed portion gives you a floor on your repayments, while the variable portion lets you park surplus cash in an offset or redraw funds if you need them for another deposit.
As an example, an investor purchasing a townhouse in Coburg might fix 60% of the loan for three years and leave 40% variable. The fixed portion protects them from rate increases during the initial holding period, while the variable portion allows them to deposit rental income into an offset and reduce their interest cost on that part of the loan. If they decide to sell or access equity within three years, the break costs only apply to the fixed portion, which reduces the financial penalty compared to fixing the entire loan.
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The main consideration with a split is whether the added complexity is worth it. You'll have two interest rates to monitor, and some lenders charge separate fees for each portion. If you're splitting a loan under $400,000, the difference in dollar terms between fixing half and fixing all of it may not justify the additional administration.
Interest-Only Versus Principal and Interest on Investment Loans
Most investors choose interest-only repayments for the first few years because it keeps the loan cost lower and maximises the tax deduction. The interest you pay on an investment loan is a claimable expense, but principal repayments are not. If your goal is to build wealth through property and you're also paying down an owner-occupied home loan, it usually makes sense to minimise repayments on the investment loan and direct surplus cash toward the non-deductible debt.
Interest-only periods typically run for one to five years, depending on the lender and your loan to value ratio. After that, the loan converts to principal and interest unless you apply for an extension. Lenders are more conservative with interest-only extensions than they were a few years ago, so if you're planning to keep the loan interest-only long-term, factor that into your product choice upfront.
Fixed rates can be structured as interest-only or principal and interest, and the same applies to variable rates. The rate type and the repayment type are separate decisions, though not all lenders offer interest-only on fixed terms longer than three years.
How Rate Structure Affects Refinancing and Portfolio Growth
The rate structure you choose now affects how easily you can refinance or access equity later. If you fix for five years and want to pull equity out in year three to fund another purchase, you'll face break costs unless you can add to the existing loan without discharging it. Some lenders allow top-ups on fixed loans, but the additional borrowing is usually priced at the current fixed rate, not the rate you locked in originally.
If your strategy involves acquiring multiple properties over the next few years, a variable rate or a short fixed term gives you more flexibility to restructure your lending as your portfolio grows. You can consolidate loans, move lenders for lower rates, or access equity without penalty. That flexibility is often more valuable than the short-term certainty of a longer fixed term.
We regularly see investors lock in five-year fixed rates during periods of rising rates, only to find themselves constrained when they want to act on an opportunity or refinance to access equity. If you're unsure how long you'll hold the property or whether you'll need to access equity, a variable rate or a two-year fixed term gives you more room to adapt.
What Lenders Look at When Approving Investment Loans
Lenders assess investment loan applications differently to owner-occupied loans. They apply a higher interest rate buffer when calculating your borrowing capacity, usually adding at least 3% to the current rate. They also factor in rental income, but most lenders only count 80% of the expected rent to account for vacancy and maintenance costs.
If you already own investment property, the lender will include the existing debt and rental income in their assessment. If the property is negatively geared, that reduces your borrowing capacity for the next purchase. If you're planning to build a portfolio, structuring your loans to minimise serviceability impact is just as important as choosing the right rate type.
Your deposit also affects the rate you'll be offered. Most lenders offer their lowest investor rates to borrowers with a loan to value ratio below 80%, meaning you need at least a 20% deposit to avoid Lenders Mortgage Insurance and access the most competitive pricing. If you're using equity from another property, the lender will assess the combined loan to value ratio across both properties.
Using Offset Accounts and Extra Repayments to Reduce Interest
An offset account is a transaction account linked to your loan. The balance in the offset reduces the amount of interest you're charged, without actually paying down the loan balance. If you have a $500,000 loan and $50,000 in your offset, you're only charged interest on $450,000.
Offset accounts are almost always attached to variable rate loans. They're useful for investors who receive rental income or have irregular cash flow, because you can park surplus funds in the offset and reduce your interest cost without losing access to that cash. The interest saving is also not counted as income, so it doesn't affect your tax position the way a high-interest savings account would.
If you're comparing a fixed rate with a low headline rate to a variable rate with an offset, run the numbers based on how much you're likely to keep in the offset. If you expect to hold a meaningful balance, the effective rate on the variable loan may be lower than the fixed rate, even if the headline rate is higher.
Choosing the Right Structure for Your Investment Strategy
The rate structure that works depends on what you're trying to achieve. If you're buying a single investment property and want predictable cash flow, a fixed rate makes sense. If you're building a portfolio and need flexibility to access equity or refinance, a variable rate is usually the right choice. If you want some certainty but don't want to give up offset access entirely, a split loan is a middle ground.
There's no universal answer, and the right structure for one investor may not suit another. Your decision should be based on your risk tolerance, your cash flow, and whether you expect to make changes to the loan over the next few years. If you're not sure which structure fits your situation, a conversation with a broker who understands investment lending can help you think through the trade-offs before you commit.
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Frequently Asked Questions
Should I fix or go variable on an investment loan?
It depends on your strategy and risk tolerance. A fixed rate gives you certainty over repayments and makes cash flow easier to forecast, while a variable rate offers more flexibility to make extra repayments, access offset accounts, and refinance without penalty. If you plan to hold the property long-term and want predictable costs, fixing makes sense. If you need flexibility to access equity or restructure your lending, variable is usually the right choice.
What is a split loan and how does it work?
A split loan divides your borrowing into a fixed portion and a variable portion, each with its own rate and features. You choose the split percentage, and each portion operates independently. This gives you partial certainty from the fixed portion and partial flexibility from the variable portion, including access to offset accounts and the ability to make extra repayments on the variable side.
Can I access equity if my investment loan is fixed?
You can, but you may face break costs if you need to discharge or restructure the loan before the fixed term ends. Some lenders allow top-ups on fixed loans without breaking the existing rate, but the additional borrowing is usually priced at current rates. If you expect to access equity within a few years, a variable rate or shorter fixed term gives you more flexibility.
Why do most investors choose interest-only repayments?
Interest-only repayments keep the loan cost lower and maximise the tax deduction, because the interest on an investment loan is a claimable expense but principal repayments are not. If you're also paying down an owner-occupied home loan, it usually makes sense to minimise repayments on the investment loan and direct surplus cash toward the non-deductible debt.
How does an offset account work on an investment loan?
An offset account is a transaction account linked to your loan. The balance in the offset reduces the amount of interest you're charged without paying down the loan balance. Offset accounts are typically only available on variable rate loans and are useful for parking rental income or surplus cash to reduce your interest cost while keeping the funds accessible.
