What a Rate Lock-in Actually Does
A rate lock-in fixes your interest rate for a set period, usually between one and five years. Your repayments stay the same regardless of what happens in the broader market, which matters when you're working a roster and can't spend every swing checking rate movements.
When you lock in a rate on an investment loan, you're essentially making a bet with the lender. They agree to hold your rate steady, and you agree to pay that rate for the full term. If rates climb, you benefit. If they drop, you're stuck unless you're willing to pay break costs.
Consider a FIFO heavy diesel mechanic who locked in a three-year fixed rate at 5.8% on a $450,000 investment loan in early 2024. Rates climbed to 6.5% within twelve months. That fixed rate is now saving around $260 per month compared to the variable equivalent, which adds up to roughly $3,100 per year. The lock-in is doing exactly what it's supposed to do.
How Break Costs Get Calculated
Break costs appear when you exit a fixed rate loan before the term ends. The amount depends on the difference between your locked rate and what the lender can now charge for the remaining period.
Lenders calculate break costs using wholesale interest rates, not the advertised rates you see online. If wholesale rates have dropped since you fixed, the lender loses money by letting you out early. That loss becomes your break cost. If wholesale rates have climbed, there's usually no break cost because the lender can now lend that money at a higher rate.
In the scenario above, if that same mechanic needed to refinance or sell the property halfway through the fixed term, and wholesale rates had fallen to 4.9%, the break cost could easily hit $8,000 to $12,000. The lender is recovering the difference between what you're paying and what they can now earn on that money for the remaining 18 months.
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When Break Costs Are Worth Paying
Break costs aren't always a deal-breaker. If you're refinancing to access equity for a second property, or if you've found a rate that's low enough to offset the cost over the remaining term, it can still make sense to move.
You need to do the actual calculation. Take the break cost, divide it by the number of months left on your fixed term, and add that to the new monthly repayment. If the total is still lower than what you're currently paying, or if you're gaining something else like offset features or equity access, the break cost might be justified.
In our experience, most break cost decisions come down to portfolio growth. If you're cashed up from a few strong rosters and there's a property that fits your investment strategy, paying $10,000 in break costs to access $150,000 in equity can be the right call. The break cost is a sunk expense, but the second property starts building equity immediately.
Fixed Rate Lock-ins and Offset Accounts
Most fixed rate investment loans don't come with offset accounts. That's a problem if you're rostered on and earning strong coin while the loan sits idle. Your surplus cash earns interest in a savings account at maybe 4%, while your loan is costing you 5.8%. The gap is dead money.
Some lenders offer partial offset on fixed rates, but the fixed rate itself is usually higher to compensate. You need to calculate whether the offset benefit outweighs the rate increase. For a FIFO worker with variable income, the offset flexibility often wins, which is why split loans are common. You fix half the loan for rate security and leave half variable with full offset.
Split Loan Structures for Investment Properties
A split loan lets you lock in part of your investment loan while keeping the rest variable. It's a middle option that gives you some rate protection without losing all your flexibility.
You might fix 60% of the loan at 5.7% and leave 40% variable at 6.3% with full offset. If rates climb, the fixed portion cushions the blow. If rates drop, you're only locked in on part of the loan. If you need to refinance or sell, the break cost only applies to the fixed portion, which reduces the financial hit.
The exact split depends on your risk tolerance and cash flow. If you're paying principal and interest and the rental income covers most of the repayment, you might fix a higher percentage. If you're on interest only and relying on offsets to manage tax, you'd probably keep more of the loan variable.
What Happens When Your Fixed Term Ends
When your fixed rate expires, the loan automatically rolls to the lender's standard variable rate. That rate is almost always higher than the advertised rates for new customers, sometimes by 0.5% or more.
You've got a few options. You can refix at the current rates, switch to variable, or refinance to another lender. Most FIFO workers refinance at this point if they've been with the same lender for more than two years. Loyalty doesn't pay in home loans, and lenders know it.
If you're planning to hold the investment property long-term, this is also the time to review your loan structure. You might have been on interest only for the first five years, and now you're switching to principal and interest as the property's value has climbed and the rental income has increased. Or you're pulling equity out to fund the next purchase.
Rate Lock-ins and the Recent CGT Changes
The Federal Budget changes from May 2026 affect how you think about holding periods, which flows through to your fixed rate decisions. If you bought an established investment property after Budget night, the 50% CGT discount no longer applies from July 2027, and negative gearing is limited to offsetting property income only.
That changes the calculation for short-term holds. If you're planning to flip a property within three to five years, you're now facing a minimum 30% tax on capital gains and limited negative gearing benefits. Fixed rates still protect you from rate rises, but the overall return on the investment is lower, which makes break costs even harder to justify.
If you bought before Budget night or you're holding new builds, the old rules still apply to your existing gains, so your fixed rate strategy stays the same. The lock-in still makes sense if you're holding long-term and building equity through principal paydown and capital growth.
Call one of our team or book an appointment at a time that works for you. We'll run the numbers on your current fixed rate, calculate any break costs if you're thinking of moving, and work out whether locking in part of your next investment loan makes sense for your roster and your equity position.
Frequently Asked Questions
What is a rate lock-in on an investment loan?
A rate lock-in fixes your interest rate for a set period, usually one to five years, so your repayments stay the same regardless of market movements. You're protected from rate rises, but you're also locked in if rates fall unless you pay break costs to exit early.
How are break costs calculated on a fixed rate investment loan?
Break costs are based on the difference between your locked rate and the current wholesale rates for the remaining fixed term. If wholesale rates have dropped since you fixed, the lender charges you the lost interest they would have earned. If wholesale rates have risen, there's usually no break cost.
Can I use an offset account with a fixed rate investment loan?
Most fixed rate investment loans don't offer offset accounts. Some lenders provide partial offset on fixed rates, but the rate itself is usually higher to compensate. A split loan structure lets you fix part of the loan for security while keeping the rest variable with full offset.
What happens when my fixed rate term ends?
Your loan automatically rolls to the lender's standard variable rate, which is usually higher than advertised rates for new customers. At this point, you can refix at current rates, switch to variable, or refinance to another lender for a lower rate.
When are break costs worth paying on an investment loan?
Break costs can be justified if you're refinancing to access equity for another property, or if the new rate is low enough to offset the cost over the remaining term. Calculate the break cost divided by months remaining, add it to the new repayment, and compare it to your current situation.
