How to Get a Big Loan When Your Income Swings Around

If your income jumps around from year to year, you can still get a large home or investment loan — but lenders will not use your best year and ignore the rest. They’ll usually average two or more years, shade anything volatile, and then apply a 3% serviceability buffer on top. Your job is to turn a messy income story into a stable one the bank can trust, without putting yourself under unsafe pressure.

This guide is written for high‑earning Australians — executives, partners, self‑employed owners and investors — who see big swings in income and still want to move on a significant purchase or refinance this year.

1. Why volatile income worries banks (and should worry you too)

Year‑to‑year income swings are common for:

• Executives with large bonuses, equity and profit share
• Partners, directors and practice owners with variable distributions
• Self‑employed professionals whose profits rise and fall
• Investors relying on rents, dividends and trust distributions

From a lender’s point of view, volatile income raises two questions:

1. Is this income level repeatable?
2. Can this borrower still pay if the next year is a “lean” one?

Roy Morgan estimates around 28% of Australian mortgage holders are already at risk of mortgage stress, with higher risk as rates rise. If you rely on a big year to justify a big loan, you could join that group quickly if bonuses or profits fall.

Working rule: even if the bank will lend more, keep total home and investment repayments around 30–35% of after‑tax income under a 3% rate buffer.[4]

2. How banks actually read big income swings

2.1 The core idea: stability beats headline income

Most Australian lenders care less about your maximum income and more about your dependable income — what still shows up in average or below‑average years.

Common lender habits (policies differ by bank):

• Take 2 years of income, sometimes 3 for self‑employed
• Average the years, or use the lower year if the latest year jumps too sharply
• Shade (discount) volatile components: bonuses, commissions, overtime, distributions
• Add an APRA‑style 3% buffer on the interest rate for serviceability

That means your borrowing power is usually based on a conservative, normalised income, not the year you “knocked it out of the park”.

2.2 How lenders treat different types of fluctuating income

For a deeper dive on investment and trust income, see How to Use Investment Income and Trust Distributions for a Home Loan.

2.3 Simple worked example: bonus swings

• Year 1: Base $250,000 + bonus $150,000 = $400,000 total
• Year 2: Base $260,000 + bonus $30,000 = $290,000 total

You might think of yourself as a $350k+ earner. A conservative lender might calculate:

• Average bonus: ($150k + $30k) / 2 = $90k
• Shade bonus to 70%: $90k × 70% = $63k
• Add base: $260k + $63k = $323k usable income

A stricter lender may just take Year 2’s bonus ($30k) and shade it to 70% = $21k. Usable income then becomes $281k.

The gap between how you see your income and how a bank does can easily be $50–100k.

For more nuance on how lenders treat bonuses and profit share, see the cluster sibling “How Lenders Treat Bonuses, Commissions and Profit Share for High‑Income Professionals” when it’s live.

3. Averaging, outliers and “normalising” your income

Banks smooth out big year-to-year swings to find your sustainable income level.

3.1 The two‑ or three‑year income story

Think of your last 2–3 years as one story:

• Year A – low: parental leave, sabbatical, COVID, project timing
• Year B – normal: typical hours, no major surprises
• Year C – high: big bonus, sale event, one‑off distribution

Lenders are trying to find “normal”. They will often:

• Average B and C if A is clearly an anomaly and explained well
• Use the lower of B and C if C is much higher and looks one‑off
• Ask for more detail if income is rising or falling steeply

Your role is to document the anomalies so underwriters are comfortable calling them one‑off.

3.2 Normalising adjustments with your accountant

This is where your tax advisor and broker must work together. Aggressive tax minimisation — deferring income, pushing deductions forward, or shifting income to lower‑tax entities — can backfire when you need a loan.[1][17][18]

Common normalising steps:

• Add back non‑cash items (e.g. depreciation)
• Adjust for one‑off expenses (legal, setup costs, repairs) with clear evidence
• Clarify temporary income drops (parental leave, big gap year, COVID impact)
• Separate discretionary reinvestment from underlying profitability

The goal is not to inflate your income, but to show the bank what a typical, recurring year looks like — with paperwork to match.

For a tax‑aware lens on this, see Tax‑Aware Mortgage Strategies for Alexandria Owners to Lift Borrowing Power.

3.3 Example: self‑employed profit swings

Assume company profit before tax in your returns:

• FY23: $520,000
• FY24: $320,000 (after a one‑off $150k legal settlement)

Without explanation, a lender might average to $420k or even lean towards the lower figure.

If your accountant prepares a note showing the $150k as a non‑recurring expense with legal invoices attached, some lenders will treat “normalised” profit closer to $470k, improving borrowing power without misrepresenting risk.