Last updated: July 2026 · Reviewed by John Pierre Saliba, Director and Mortgage Broker, MFAA Accredited
Home Loan Structure, Why It Matters More Than You Think
The interest rate on your home loan gets most of the attention, but the structure of your loan (offset vs redraw, split vs whole, P&I vs IO) can save or cost you almost as much as the rate over time. Getting the structure right from day one, particularly for investors and tax-conscious borrowers, is one of the most important things we do as brokers.
The most common structuring mistake I see is owner-occupiers putting their investment loan surplus into a redraw on their investment loan rather than an offset on their owner-occupier loan. When they redraw for personal use, the ATO may deny deductibility on that portion, because the funds changed purpose. An offset on the owner-occupier keeps personal funds completely separate from the investment debt. Structure matters as much as rate.
Offset Account vs Redraw Facility
Offset Account
A savings account linked to your home loan. The balance in your offset reduces the loan balance on which interest is calculated, daily. $50,000 in an offset account on a $600,000 loan means you pay interest on $550,000. You can withdraw offset funds at any time without affecting the loan balance or the loan's tax treatment.
Redraw Facility
Allows you to access extra repayments you've made above the minimum. If you've paid $30,000 extra on your loan, you can redraw up to $30,000. Redraw is slightly less flexible than offset, some lenders have minimum redraw amounts or take 1–5 business days to process. More importantly, redrawing from an investment loan for personal purposes can create ATO deductibility issues.
Which Is Better, Offset or Redraw?
- Owner-occupier: Offset is almost always better, maximum flexibility, funds remain clearly personal
- Investment loan: Redraw is often preferred, keeping the investment account clean and deductibility clear. If you use funds from the account, they go back into the loan (not a separate account that might be used personally)
- For tax deductibility: Never mix personal funds with investment loan accounts. Offset on owner-occupier; avoid drawing investment loan funds for personal use
Split Loans
A split loan divides your mortgage into two or more portions, typically one fixed and one variable. Benefits:
- Fix part of your loan for repayment certainty
- Keep part variable for flexibility (offset account, extra repayments)
- Balance certainty and flexibility, particularly useful when rates are uncertain
Common split: 50/50 or 60/40 fixed/variable. The variable portion holds the offset account.
P&I vs IO, Structuring for Your Purpose
- Owner-occupier: P&I almost always, interest not deductible, so reducing principal is tax-efficient. Lower rate than IO.
- Investment property: IO often preferred in accumulation phase, maximises deductible interest, preserves cash flow, lower repayments.
- Both? P&I on owner-occupier, IO on investment = optimal tax and equity structure for most investors
The Optimal Structure for an Owner-Occupier with Investment Property
- Owner-occupier loan: P&I, variable, with full offset account. Salary paid into offset.
- Investment loan: IO, variable, separate account at different lender or split. Rent received into separate account.
- No cross-collateralisation between properties.
- Extra savings in owner-occupier offset, reducing non-deductible interest daily.
