Investment
Investment Property Finance: Cash Flow, Negative Gearing, and the Servicing Wall
Property investment finance carries a different lens. Lenders typically don't assess investment loans the way they assess owner-occupier loans, and the assumptions investors make about rental income, negative gearing and tax deductions rarely match how a bank's servicing calculator treats them. The result is that investors with strong portfolios sometimes receive lower borrowing capacity than first-home buyers with smaller deposits.
How lenders typically treat rental income
Most lenders include 70% to 80% of gross rental income in servicing. The remainder is generally assumed to cover vacancy, maintenance, agent fees, insurance and rates. Some lenders take 100% of gross rent and then apply a higher operating-expense haircut elsewhere; the outcome usually arrives at a similar net figure. Industry sources note that several lenders tightened their rental-income shading through the early part of 2026 as part of a broader cooling in investor lending conditions.
A current lease is typically required. For a new-build property with no tenant yet, the lender may accept a market-rent appraisal from a registered valuer or licensed agent. The figure ultimately used in servicing is often the lender's interpretation of that appraisal, not the headline number on the agent's letter.
Holiday lets, short-stay and Airbnb income tend to be treated cautiously. Some lenders may accept this income with twelve months of statements. Others discount it heavily or exclude it entirely. The lender choice for a short-stay-positioned property can change borrowing capacity meaningfully.
Why negative gearing rarely helps borrowing capacity
Negative gearing is a personal tax position. It doesn't change the cash flow the bank sees from the investment property itself. Some lenders may add back the tax saving from negative gearing to assessable income. Many do not.
Where it is added back, the calculation typically uses the lender's assumed marginal rate, which is often lower than the borrower's actual rate. The practical effect: a twenty thousand dollar annual negative-gearing benefit at the personal level might add four to seven thousand dollars to assessable income at the lender, subject to lender criteria.
Investors who plan around the personal tax outcome and assume it will translate proportionally to borrowing power are often surprised by the gap.
From 1 February 2026, the right lender is no longer just the one with the most generous servicing calculator. It is also the one with current capacity under the DTI cap.
The portfolio servicing wall
Each existing investment loan is typically assessed at the lender's assessment rate, not the borrower's actual rate. The assessment rate currently sits at around three percentage points above the contracted rate, in line with APRA's prudential serviceability buffer. APRA set the buffer at 3% in October 2021 and confirmed in 2025 that it would remain at that setting.
For an investor with three properties at 6.0% actual, the lender may service that debt at around 9.0%. The cost of carry assumed by the calculator can be significantly higher than the cost the investor actually pays. This is often the mechanism behind the borrowing wall portfolio investors hit earlier than expected.
Different lenders apply the buffer slightly differently. A handful may recognise existing debt at a smaller margin if the loan is fixed for a meaningful term. Others apply the full buffer regardless. Lender selection at the next purchase can compound across every future purchase.
The 2026 DTI cap and what it means for investors
From 1 February 2026, APRA introduced a debt-to-income (DTI) limit on Australian lenders. Authorised deposit-taking institutions are required to keep new lending at DTI of six times income or higher to no more than 20% of new mortgage flows. The limit applies separately to owner-occupier and investor portfolios, measured quarterly. Bridging loans and loans for the purchase or construction of new dwellings are exempt.
The practical effect for investors: lenders with significant investor exposure may tighten DTI policy ahead of their cap to leave headroom. APRA data shows around 10% of investor loans were already sitting at DTI of six or above when the rule was announced. Lenders close to the threshold may decline files that previously would have approved.
For Maxfin clients, this changes the lender-selection question. The right lender is no longer just the one with the most generous servicing calculator; it's also the one with current capacity under the DTI cap. That capacity moves quietly from quarter to quarter.
Interest-only versus principal and interest for investment
Interest-only typically carries a rate premium, often around 0.20% to 0.40% above the equivalent principal-and-interest rate, subject to lender criteria. Lender policy commonly limits the maximum interest-only term to around five years on owner-occupied loans. Investment loans may be eligible for longer cumulative interest-only periods, sometimes extended across resets, depending on lender policy and credit assessment at each renewal. There is no current APRA-mandated maximum on interest-only term length; the limits are set by individual lenders.
The tax position generally favours interest-only on investment debt, because interest is deductible and principal repayments are not. The servicing position complicates the picture: lenders typically calculate interest-only loans on the underlying principal-and-interest obligation that follows the interest-only period, not on the interest-only repayment itself.
An interest-only loan can therefore reduce the borrower's actual cash outflow today while doing very little to free up borrowing capacity for the next purchase. The decision is generally best made on tax and cash-flow grounds, not on a misread of how it affects servicing.
The structural choices that compound
Decisions made on a single transaction can shape every subsequent one. The structural choices that tend to matter most over a ten-year portfolio horizon:
- Loan splits: separating deductible from non-deductible debt can help protect deductibility if a property later changes between investment and owner-occupied use.
- Cross-collateralisation versus standalone: cross-securing properties may simplify one transaction but can constrain every future one. Releasing a security from a cross-collateralised structure is rarely simple.
- Offset accounts on investment debt: can preserve deductibility while parking idle cash, instead of paying down principal that may not be easily redrawn for investment purposes without affecting deductibility.
- Lender selection and DTI capacity: from February 2026, capacity under each lender's DTI cap is a live constraint. Switching at the wrong moment can lock a borrower out of that lender for six to twelve months.
How Maxfin structures investor files
The firm maps the existing portfolio's servicing position before recommending the next move. The number that matters is not the headline borrowing capacity at one lender; it is the position across the panel after the next purchase settles.
Maxfin tracks which lenders currently have appetite for additional investor exposure and which are restricted under prudential settings. A lender that approved an investor file last quarter may have closed appetite this quarter without public announcement.
New lending is generally structured to preserve deductibility and to avoid cross-collateralisation by default. The firm coordinates with the client's accountant before settlement on offset structures, split-loan setup and the ownership entity used for the purchase.
General information only. Not credit advice and not tax advice. Lending outcomes depend on individual circumstances and are subject to lender credit criteria, terms and conditions. Where tax considerations are described, they are general in nature; advice on a specific tax position should be obtained from a registered tax agent or accountant. Maxfin holds Australian Credit Licence 384406 and is not a registered tax agent.