Refinance Investment Property: Tax Deduction Continuity Rules
Introduction
Refinancing an investment property loan is a routine corporate and personal treasury exercise in Australia. Borrowers seek lower interest margins, release equity, or consolidate facilities. The Australian Taxation Office (ATO) does not impede refinancing, but it applies a continuity-of-purpose test that can unwind interest deductions if the refinancing alters the borrowed capital’s character. This analysis sets out the operative tax rules, the ATO’s published view in Taxation Ruling TR 98/22, and the structuring protocols that preserve deductibility of interest on refinanced investment debt. Every percentage-point change in the Reserve Bank of Australia (RBA) cash rate alters the after-tax cost of borrowing, and a misstep in structuring a refinance can convert a deductible interest stream into a non-deductible private expense. The article does not constitute personal financial advice; borrowers must consult a licensed mortgage broker and a registered tax agent before acting.
The Core Principle: Loan Purpose Over Security
Deductibility of interest on borrowed funds is determined by the use of the funds, not the asset over which a security is taken. Section 8-1 of the Income Tax Assessment Act 1997 (Cth) permits a deduction for interest incurred in gaining or producing assessable income. For an investment property, the borrowed money must be applied directly to the income-producing asset or to an expense connected with that income. The mortgage registered on title is merely security; the legal test attaches to the purpose for which the borrowed capital was deployed.
When a taxpayer refinances an existing investment loan, the ATO treats the new loan as a continuation of the original borrowing, provided the refinance does not increase the quantum of debt used for a non-income purpose. That is the continuity-of-purpose rule. The ATO’s guidance in TR 98/22 confirms that a refinancing will not disturb deductibility if the new borrowed funds replace an existing income-producing debt and are applied to discharge that debt. The ruling states unequivocally: “A refinancing does not of itself cause the interest on the new loan to lose its character as an outgoing incurred in gaining or producing assessable income.”
The corollary is critical: if a refinance draws additional equity for private expenditure—renovating a main residence, purchasing a motor vehicle, funding a holiday—that proportion of the new loan is not referable to an income-producing purpose. Interest on the added component is non-deductible, and apportionment will apply. The ATO’s rental property guide for the 2023–24 income year Rental properties 2023–24 makes clear that “you can only claim interest on a loan used to purchase the rental property, or to make improvements to it.” Any other use breaks the nexus.
Refinancing and the ATO’s Compliance Focus
The ATO’s data-matching capabilities now cross-reference loan account conduct with tax return entries. In the 2022–23 financial year, the ATO reviewed over 60,000 rental property schedules and adjusted deductions in approximately 38 per cent of cases. Interest expenses are the largest single deduction item for geared investors; the ATO’s individual taxpayer compliance program flags incorrect interest claims as a material risk. Refinancing events often trigger review activity because a new loan account number appears on the bank statement, and the ATO verifies that the principal quantum and purpose align with the original borrowing.
The ATO’s public ruling TR 2004/4 provides a general framework for interest deductibility and is routinely cited in objections and Tribunal decisions. It reinforces that the test is objective: what was the money used for? The characterisation does not change merely because a different lender advances the funds or a different security property is offered.
Redrawing Equity: When Deductions Cease
A borrower who refinances and redraws equity—increasing the total debt but directing the extra funds to a private purpose—creates a mixed-purpose loan. The interest must then be apportioned between the deductible and non-deductible components. The ATO’s Interest expenses on rental properties page states: “If you redraw from your loan for private purposes, you cannot claim the interest on the private part.”
Apportionment is not always a simple ratio of account balances. Where the loan is a revolving line of credit, every deposit (including rental income credited to the account) reduces the debt. When funds are later redrawn, the ATO will trace the use. A common but fatal error is the use of an investment property offset or redraw facility to pay down the non-deductible home loan. The moment funds leave the investment loan account for a private purpose, the interest on that tranche becomes non-deductible permanently, even if the funds are later repaid. The ATO’s view, confirmed in multiple private binding rulings, is that once the nexus to income production is broken, later repayments do not restore deductibility.
Record Keeping and Documenting the Refinance
To sustain a deduction on refinanced debt, the taxpayer must maintain records that trace the borrowed funds from the original lender through any interim accounts to the new facility. The ATO expects the following evidence:
- Original loan agreement and settlement statement identifying the property acquired.
- Statements showing the application of funds at the time of the initial purchase.
- Refinance settlement statement demonstrating that the new loan discharged the exact outstanding balance of the old loan.
- A clear account structure that segregates any additional borrowings for non-income purposes.
The ATO’s Keeping rental property records guidance underscores the five-year retention obligation. Digital scanning is acceptable, but the documents must be legible and contemporaneous. In an audit, the ATO will request a reconciliation of the loan balance over the life of the property. Any unexplained jump in debt or a deposit into a non-investment account will invite apportionment.
Structured Refinancing: Split Loans and Separate Facilities
Tax practitioners routinely advise borrowers to structure a refinance using a “cleansed” facility architecture. The most robust method is a split loan: one sub-account that exactly matches the outstanding deductible investment debt, and a second sub-account (or a separate loan entirely) for any private redraw. The investment sub-account can then be refinanced further without contaminating its purpose. The ATO accepts this segregation. Lenders in the Australian market—major banks and non-bank lenders—offer loan-splitting functionality as a standard product feature.
Where a borrower wishes to release equity for a future income-producing purpose (such as a deposit on another investment property), the new borrowing must be documented as a separate facility, and the settlement statement must show the proceeds directed to the income-producing asset. This maintains the deductibility of interest on that component under the general principles of TR 2004/4. The ATO’s compliance resources indicate that a properly structured split loan will survive review, provided the borrower never intermingles funds.
Interest Rates and Refinancing Decisions in 2025
Monetary policy settings affect the calculus of refinancing. As at 18 February 2025, the RBA reduced the cash rate target from 4.35 per cent to 4.10 per cent (RBA media release). Variable investment-property rates quoted by major lenders sit in a range of approximately 6.30 per cent to 6.80 per cent per annum, while fixed rates for one to three years are modestly lower, around 5.89 per cent to 6.19 per cent. The Australian Prudential Regulation Authority’s serviceability buffer of 3 percentage points above the loan product rate (APRA APS 220) has constrained borrowing capacity. For many investors, refinancing to a lower-rate product can generate a gross saving of 30 to 60 basis points. However, break costs on a fixed-rate loan must be factored into the net benefit, and any mortgage discharge and establishment fees—typically $300 to $800 per security—reduce the first-year advantage.
The after-tax cost of investment debt is a function of the nominal interest rate and the investor’s marginal tax rate. For an investor on the 47 per cent marginal rate (including the Medicare levy), a 6.50 per cent gross interest expense translates to an after-tax cost of approximately 3.45 per cent. Any event that compromises deductibility effectively doubles the after-tax cost of that debt component. The integrity of the deduction is therefore as material as the rate spread itself.
Anti-Avoidance and the “Purpose” Test in Practice
The ATO has challenged arrangements where refinancing is structured to artificially inflate the deductible debt. One example involves a taxpayer who uses redrawn equity to pay down a home loan, then redraws again to invest, claiming the entire debt as deductible. The ATO’s approach in Taxation Determination TD 2012/22 outlines the “link” between borrowings and income-producing use. If the true objective of a series of transactions is to replace private debt with deductible debt, Part IVA of the Income Tax Assessment Act 1936 may apply to cancel the deduction. Courts have upheld this analysis in cases such as Fletcher v FCT and Hart v FCT. Taxpayers must therefore ensure the commercial substance of the refinance aligns with its documented form. The refinance must be a genuine replacement of the investment borrowing; it cannot be a circuitous method of converting non-deductible private interest into a tax deduction.
Conclusion
Refinancing an investment property in Australia does not, of itself, threaten the deductibility of interest. The ATO’s long-standing administrative practice, reflected in TR 98/22 and TR 2004/4, preserves the deduction where the new loan simply replaces the existing income-producing debt. The hazard lies in the redraw of additional equity for private purposes. A taxpayer who maintains a split-loan architecture, retains complete settlement records, and never intermingles non-income funds with the investment facility will ordinarily satisfy the continuity-of-purpose test. Every decision should be documented, and the interest deduction claimed only on the portion of debt demonstrably linked to the rental property or to another assessable income source. Given the materiality of the deduction—often the largest line item on a rental schedule—a pre-refinance review by a tax adviser is a prudential step.
Information only, not personal financial advice. Consult a licensed mortgage broker and a registered tax agent before refinancing an investment property.