Top Strategies to Lock Fixed Rates on Investment Loans

A fixed rate on an investment loan protects rental cash flow from rate rises and creates certainty for tax planning.

Covering the gap between rent and repayments becomes predictable when your rate is locked. Many investors in Canterbury refinance variable debt to fixed terms once they have committed to holding a property for three to five years, particularly when rental vacancy in the area remains low and they want to secure stable returns without the risk of servicing pressure from rate increases.

Fixed Rate Investment Loan Features and How They Differ from Variable

Fixed rate investment loans lock your interest rate for a set term, typically between one and five years. During that period, your repayments remain the same regardless of Reserve Bank movements. Variable rate loans move with the market and typically offer offset accounts, unlimited extra repayments, and the ability to redraw without penalty.

Fixed loans generally do not offer offset functionality. Some lenders permit limited extra repayments, often capped at $10,000 to $30,000 per year, but funds paid above the scheduled amount usually cannot be redrawn. Break costs apply if you repay the loan in full, sell the property, or refinance before the fixed term ends. These costs reflect the lender's funding loss and can run into thousands of dollars depending on how far rates have moved since you locked in.

Interest Only Terms and Why Investors Use Them on Fixed Loans

Interest only repayments are available on fixed rate investment loans for terms up to five years. Repayments cover interest charges only, leaving the loan balance unchanged. This keeps monthly costs lower and maximises the tax deduction, because all interest paid on an investment loan remains deductible provided the property is rented or genuinely available for rent.

Consider an investor who purchases a two-bedroom unit in Canterbury. The property generates $2,400 per month in rent. On an interest only fixed loan, monthly repayments might sit at $2,600, leaving a gap of $200 after rent is received. That gap is funded from other income, but the full $2,600 in interest can be claimed against taxable income. Switching to principal and interest repayments would increase the monthly cost by several hundred dollars while reducing the claimable deduction, because only the interest portion remains deductible. For investors holding multiple properties or planning to use equity for further purchases, interest only terms preserve cash flow and borrowing capacity.

Split Loan Structures That Combine Fixed and Variable Portions

A split loan divides your total borrowing between fixed and variable portions. One part is locked at a fixed rate, the other remains variable with full offset and redraw access. This structure is common among Canterbury investors who want rate protection on most of their debt but need liquidity for repairs, agent fees, or future deposits.

In our experience, investors split 70 to 80 per cent of the loan to a fixed rate and leave the remainder on a variable rate linked to an offset account. Rental income and surplus cash sit in the offset, reducing interest on the variable portion while the fixed portion provides certainty on the bulk of the debt. If the property is sold or refinanced, only the fixed portion attracts break costs. The variable portion can be repaid in full at any time without penalty. Lenders typically allow you to choose your own split ratio when the loan is established, and some permit you to adjust the split at the end of each fixed term without refinancing the entire loan.

Break Costs and When They Apply to Fixed Investment Loans

Break costs are charged when you exit a fixed rate loan before the agreed term expires. The cost compensates the lender for the difference between the rate you locked in and the rate at which the lender can now reinvest the funds. If market rates have fallen since you fixed, the cost will be higher. If rates have risen, the cost may be zero or close to it.

Break cost formulas vary by lender but generally reflect the interest rate differential multiplied by the outstanding loan balance and the remaining fixed term. A borrower who fixed $500,000 for five years and sells the property after two years could face break costs in the range of $15,000 to $25,000 if rates have dropped substantially during that period. Most lenders provide a break cost estimate on request, and the figure is usually confirmed a few days before settlement. Refinancing to a new lender during a fixed term will trigger these costs unless rates have moved in your favour.

Portability and Whether You Can Transfer a Fixed Loan to a New Property

Portability allows you to transfer an existing fixed rate loan to a new property without breaking the fixed term. Not all lenders offer this feature, and those that do often impose conditions. The new property must be of equal or greater value, settlement dates must align within a narrow window, and the loan amount generally cannot increase beyond a small tolerance.

If you sell an investment property in Canterbury and purchase another within the same month, portability may allow you to avoid break costs and keep your locked rate. However, if the new property requires a larger loan or settlement is delayed, portability may not be available. In that scenario, you would either need to break the fixed loan and refinance, or retain the existing loan and take out a separate loan for the additional amount. Portability is particularly relevant for investors upgrading within a suburb or consolidating two smaller holdings into one larger asset.

Rate Lock Periods and How to Protect Against Rate Rises Before Settlement

A rate lock allows you to secure a fixed rate before your loan settles. Most lenders offer rate locks for 90 days from the date of approval, though some extend this to 120 days for construction or off-the-plan purchases. If rates rise during that period, your rate remains unchanged. If rates fall, most lenders do not permit you to relock at the lower rate unless you withdraw and resubmit the application.

For investors purchasing established property in Canterbury, settlement typically occurs within 60 to 90 days of contract signing. If you apply for finance immediately after exchange and rates are trending upward, locking the rate at approval protects you from increases before settlement. Construction loans and new apartment purchases often have longer lead times, and some lenders charge a fee to extend the lock period beyond the standard 90 days. Investment loans for new builds may also qualify for different tax treatment, so rate lock timing should be considered alongside settlement and depreciation schedules.

Using Fixed Rates to Support Debt Serviceability and Future Borrowing

Lenders assess your ability to service a new investment loan by applying a serviceability buffer of 3.0 percentage points above the loan rate. A fixed rate loan is assessed at the fixed rate plus the buffer, while a variable loan is assessed at the variable rate plus the buffer. During periods when fixed rates sit below variable rates, locking in a fixed rate can improve your borrowing capacity for future purchases by lowering the assessed repayment.

This becomes relevant when you plan to acquire a second or third investment property within a few years. A lower assessed repayment on your existing debt leaves more room in your serviceability calculation for the next loan. If you hold a $600,000 loan on a Canterbury property at a fixed rate and apply for a second loan 18 months later, the lender will assess the fixed loan at its locked rate rather than a higher variable rate, provided the fixed term has not yet expired. That difference can amount to several hundred dollars per month in assessed repayments and may determine whether the new loan is approved.

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