Investors may consider interest-only repayments when buying, refinancing or refixing an investment property. The immediate effect is lower scheduled repayments because the borrower pays interest without reducing principal. That can improve holding-period cash flow, but it also leaves the debt unchanged and generally increases total interest over the life of the loan.
The relevant question is what the investor will do with the cash flow released and how the principal will ultimately be repaid. Interest-only can be a deliberate structure where there is a defined strategy and adequate risk capacity; without that discipline, it simply defers principal repayment. Our guide to loan repayment structures explains the broader difference between principal and interest, interest-only and capitalised interest. This article focuses on the investor decision, the trade-offs and what happens when the interest-only period ends.
Is It Better to Pay Interest Only on an Investment Property?
It depends on the investor’s objective, cash-flow position and exit or debt-reduction plan. Interest-only lowers scheduled repayments and leaves principal outstanding. Principal-and-interest repayments are higher but progressively reduce debt. The benefit of interest-only is therefore liquidity and timing, not a reduction in what is ultimately owed.
For illustration, take an $800,000 loan at a constant 5% rate over 30 years, before fees and tax. Interest-only payments are about $3,333 a month. Principal-and-interest payments are about $4,295. The difference is approximately $962 a month, or $11,540 a year. Actual repayments will vary with rates, timing and lender terms.
None of that monthly difference reduces principal. The full $800,000 remains outstanding until it is repaid through scheduled principal payments, refinance, sale or another capital event. Bank interest-only terms vary materially by lender, borrower and property and are subject to affordability and suitability assessment; renewal is not automatic. Short-term first-mortgage investment property loans operate over a different horizon. ASAP Finance’s investor facilities are usually structured for three to twelve months, with interest-only, part-interest-only or capitalised options depending on the security and exit.
Why Investors Pay Interest Only on Investment Property
Interest-only is materially more common in investor lending than in owner-occupier lending. Reserve Bank data for August 2026 show approximately $456 million of investor interest-only lending out of $1.398 billion of total investor lending, compared with approximately $782 million of owner-occupier interest-only lending out of $5.706 billion. The structure reflects investors’ greater focus on holding-period cash flow and capital allocation, but it carries clear trade-offs.
1. Improving rental cash flow during the holding period
Rates, insurance, maintenance, vacancy and property-management costs can create a cash-flow shortfall between rent received and the property’s total outgoings. Interest-only can reduce the monthly top-up required, but it does not improve the underlying rent or reduce principal.
Used well, it can preserve liquidity while a sound investment moves through a defined period of higher costs or planned value-add. Used poorly, it can mask an investment that is not viable at current rents, costs and rates. The shortfall may return, and repayments may rise, when the interest-only period ends.
2. Keeping capital available for the next acquisition
Retained cash flow can be redeployed. In the example above, one $800,000 loan releases about $11,500 a year compared with principal-and-interest repayments; two equivalent loans would release about $23,000. That money may be held as a contingency, used for property improvements or applied to another investment. Recycling equity in this way is one of the benefits of investing in residential property, but the benefit exists only if the additional liquidity supports a deliberate portfolio or risk-management objective.
If the released cash flow is absorbed by general spending, the investor has accepted higher lifetime interest without reducing debt or improving the asset. Ring-fencing the savings and tracking its use is therefore part of the strategy.
3. Matching the structure to a defined holding period
Where a sale, refinance or development is already planned within a defined period, an investor may prefer to retain liquidity rather than accelerate principal repayment. That does not mean principal reduction has little value: paying down debt lowers future interest and improves leverage. Interest-only is justified only where the alternative use of cash is expected to create a better risk-adjusted outcome, and the exit is credible.
That logic breaks down where the exit is vague. A defined sale, refinance, principal-reduction plan or other evidenced capital event is a structure; an intention to deal with the debt later is deferral.
What Interest-Only Does Not Change
Four core points remain, although lender treatment can vary.
- Borrowing capacity. Moving to interest-only does not by itself increase income, reduce debt or change security value. Banks still apply their affordability and servicing models, which may test repayments on a principal-and-interest or stressed-rate basis.
- DTI and LVR position. The repayment type does not change the loan balance or property value, so it does not directly improve DTI or LVR. Current Reserve Bank DTI settings allow banks to make up to 20% of new investor lending above a DTI of 7, with specified exemptions, and the rules do not apply to non-bank lenders. Banks also apply their own criteria.
- Total interest cost. Because principal does not reduce during the interest-only period, total interest will usually be higher than under an equivalent principal-and-interest schedule, all else equal.
- Equity position. Interest-only does not build equity through principal repayment. Equity may still change if the property value moves or capital is invested in improvements, but the borrower remains more exposed to valuation movements than under a reducing loan.
From 1 April 2025, residential investors may generally claim 100% of deductible interest where the borrowing is used for the income-earning property and the general deductibility rules are met. The deduction relates to qualifying interest, not principal, and depends on the use of funds, ownership structure and the taxpayer’s circumstances. Interest-only should not be selected solely for a tax outcome; obtain accounting or tax advice.
What Happens When the Interest-Only Period Ends
The principal balance is unchanged, but there is less of the original term left in which to repay it. Scheduled repayments therefore rise when the loan switches to principal and interest, unless the term, balance or rate also changes.
Using the same $800,000 loan, constant 5% rate and 30-year original term, five years of interest-only leaves $800,000 to repay over 25 years. The principal-and-interest payment would then be about $4,677 a month, approximately $1,344 above the interest-only payment and about $382 above the payment that would have applied from day one. On these assumptions, total interest is about $57,000 higher. This is illustrative only and excludes fees, rate changes and tax.
Plan for expiry from the outset. A lender may reassess income, expenses, DTI, LVR, conduct and overall suitability before approving a further interest-only period. The contracted end date is known, but renewal remains at the lender’s discretion and should not be assumed.
Deciding When to Switch
A switch to principal and interest may be appropriate when cash flow can comfortably support debt reduction, the investor’s holding strategy changes, the intended exit is deferred, leverage needs to reduce, or further interest-only approval is uncertain. Acting before expiry preserves more options than restructuring under time pressure.
The same logic can apply over months rather than years. An investor bridging a settlement, holding residual stock or funding an acquisition ahead of refinance may be better served by a short-term facility with the exit defined at the outset. Serviced or capitalised interest affects cash flow, peak debt and total cost differently; our guide to the cost of bridging finance explains those structures.
Structuring Investment Lending with ASAP Finance
Interest-only changes the timing of cash flows, not the repayment obligation. At ASAP Finance, first-mortgage investment lending is generally structured for three to twelve months around the security, purpose and defined exit, with interest-only, part-interest-only and capitalised options available subject to assessment. We also provide bridging loans where a genuine timing gap is the issue.
If you are assessing a short-term investment purchase, refinance or bridge and want to test the funding structure against the proposed exit, get in touch with the team at ASAP Finance.