Top tips to structure an investment loan

An investment loan finances the purchase of a residential property you rent out rather than occupy.

For a data analyst buying their first rental property, the repayment structure, rate type and offset arrangement all feed into cash flow, tax treatment and portfolio flexibility. These variables compound differently depending on whether you choose interest-only or principal-and-interest repayments, variable or fixed pricing, and whether you're buying an established dwelling or an eligible new build under current tax legislation.

Interest-Only Repayments Lower Your Outgoings Until Portfolio Income Rises

Interest-only repayments mean you pay only the interest component each month and leave the principal balance unchanged. This keeps the loan amount at its original level and reduces monthly outgoings compared to principal-and-interest repayments.

Consider a buyer who purchases a two-bedroom unit as their first rental. They arrange a five-year interest-only period on a variable-rate loan. During those five years, rental income covers most of the interest cost, body corporate fees and holding expenses. At the end of the interest-only term, the loan reverts to principal-and-interest repayments. By that point, the buyer's salary has increased and they've built a buffer in their offset account. The principal-and-interest repayment is higher, but the timing aligns with their improved serviceability.

Under APS 112, a long-term interest-only loan with an LVR above 80 per cent and a contractual interest-only period exceeding five years attracts a higher risk weight. Most lenders cap interest-only terms at five years for this reason, though you can often reapply for an extension before the term expires.

Variable Rates Let You Offset and Repay Without Penalty

A variable-rate loan adjusts when the lender changes its pricing. The rate can move up or down independently of the Reserve Bank cash rate, though lender repricing typically follows broader market changes.

Variable products usually allow full offset and unrestricted additional repayments. If you're earning a performance bonus or vesting equity in the second half of the year, you can park that cash in an offset account linked to the loan. The offset balance reduces the interest charged each day without locking the funds away. You still have access to the money if you want to put down a deposit on a second property or cover an unexpected vacancy period.

Fixed rates lock your repayment for a set term, typically one to five years. Offset is less common on fixed products, and most lenders cap annual additional repayments at around $10,000 to $30,000 without penalty. If you break the fixed term or exceed the repayment cap, break costs apply. For an analyst who values optionality and expects variable income, a variable structure usually aligns with that preference.

Established Dwellings and New Builds Are Treated Differently Under Tax Legislation From 2027-28

From the 2027-28 income year, losses on established residential investment properties acquired after 7:30pm AEST on 12 May 2026 can only be offset against income from other residential properties, including capital gains. Losses can no longer be deducted against salary or other income. Excess losses carry forward to future years.

Eligible new builds are exempt. A new build includes a dwelling constructed on vacant land or a replacement dwelling where the total number of dwellings increases. Knock-down rebuilds that do not increase dwelling numbers are not eligible. For a new build, losses remain deductible against all income, including salary, and you retain access to the 50 per cent capital gains discount at sale even after 1 July 2027.

Properties held at 7:30pm AEST on 12 May 2026, or under contract at that time, are grandfathered. Losses on those properties continue to be fully deductible against all income until you sell.

If you're considering an off-the-plan apartment or a house-and-land package, confirm with the developer or conveyancer that the property meets the definition of an eligible new build under Schedule 2 of the Treasury Laws Amendment (Tax Reform No. 1) Act 2026. The distinction determines both your deductibility treatment and your capital gains tax options for the life of the investment.

Loan-to-Value Ratio Determines Whether You Pay LMI and How Lenders Price Your Application

Loan-to-value ratio is the loan amount divided by the property's valuation, expressed as a percentage. An LVR above 80 per cent typically triggers Lenders Mortgage Insurance, which is a one-off premium calculated on a sliding scale and added to your loan or paid upfront.

For investment lending, most lenders cap LVR at 90 per cent for a single property purchase and 80 per cent if you're refinancing or buying a second property using equity from your first. Some lenders offer LMI waivers to professionals in specific occupations, though coverage for data analysts depends on the lender and your employer.

Under APS 112, investment loans attract higher risk weights than owner-occupied loans at the same LVR. Lenders price this risk into the rate and may apply a rate loading of 0.20 to 0.60 percentage points compared to an owner-occupied loan. The loading varies by lender, product and your overall financial position.

Debt-to-Income Limits Apply to New Lending From February 2026

APRA activated a debt-to-income lending limit on 1 February 2026. Each lender may approve up to 20 per cent of new investor loans to borrowers with a total debt-to-income ratio of six times or greater. The limit applies separately to investor and owner-occupier portfolios and is measured quarterly at the lender level.

If you're buying your first investment property and you already have an owner-occupied mortgage, both loans count toward your total debt when calculating the ratio. Your income includes salary, rental income from the new property, and any other assessable income the lender accepts. Most lenders shade rental income by 20 to 30 per cent to account for vacancy, maintenance and periods between tenants.

The DTI limit does not prohibit lending above six times income, but it does constrain volume. In practice, borrowers with a DTI above six often need a larger deposit, lower existing liabilities, or a strong income trajectory to be approved. If your application falls in that range, a broker can identify which lenders still have capacity under the 20 per cent allocation.

Serviceability Is Tested at Your Rate Plus 3 Percentage Points

All lenders assess your ability to service a new loan at the product rate plus a 3.0 percentage point buffer. If you're applying for a variable-rate investment loan priced at 6.5 per cent, the lender tests whether you can afford repayments at 9.5 per cent. The test applies to principal-and-interest repayments even if you choose an interest-only term.

Lenders also apply a serviceability floor to rental income. Most use 70 to 80 per cent of the market rent estimate when calculating your income. If the property rents for $600 per week, the lender may include $420 to $480 per week in your serviceability assessment. The remainder accounts for vacancy, agent fees, repairs and other holding costs.

Because the buffer and rental shading reduce your effective borrowing capacity, the loan amount you can service is often lower than the amount you could afford at the actual rate. Running scenarios in advance helps you set realistic price limits before you start searching.

Offset Accounts Reduce Interest Without Changing Your Deductions

An offset account is a transaction account linked to your loan. The balance offsets the loan principal when calculating daily interest, but the loan amount itself does not change. For tax purposes, your deductible interest is calculated on the full loan amount minus the offset balance.

If you have a loan amount of $500,000 and $50,000 in offset, you pay interest on $450,000. You can claim a deduction for the interest actually charged, which is based on the net balance. The offset does not reduce the loan principal, so it does not reduce the deductible portion of your borrowing. This structure lets you reduce interest cost without creating a mixed-purpose loan.

Offset accounts are common on variable-rate products and rare on fixed-rate products. If your income is variable or you expect lump sums during the year, an offset account gives you the flexibility to reduce interest temporarily without losing access to the funds.

Tax Deductions Include Interest, Holding Costs and Depreciation While the Property Is Rented

Interest on the portion of your loan used to acquire or hold the investment property is deductible against rental income and, depending on acquisition date and property type, against other income. Other deductible expenses include council rates, water charges, insurance, property management fees, body corporate fees, repairs and maintenance, and depreciation on the building and fixtures.

Depreciation is calculated using two schedules: capital works deductions for the building structure, and plant and equipment deductions for fixtures such as appliances, flooring and window coverings. A quantity surveyor prepares a depreciation schedule, which sets out annual deductions over the life of each asset. For established properties purchased after May 2017, plant and equipment deductions are generally limited to assets you install yourself.

Expenses are deductible for the period the property is rented or genuinely available for rent. If the property is vacant and not advertised, or if you use it for private purposes, deductions are reduced or disallowed for that period. Keep records of advertising, tenant agreements and any periods of personal use.

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