Using Bank Statements and BAS for Your Home Loan: A Practical Guide

Bank statement and BAS-based home loans are alternative documentation (alt-doc) loans where lenders use recent bank deposits and/or Business Activity Statements to prove your income instead of relying only on lodged tax returns. They’re designed mainly for self-employed borrowers and small business owners whose tax returns don’t yet show their real, current earnings.

In practice, the lender will usually:

1. Average 6–12 months of business deposits or several BAS periods.
2. Apply conservative adjustments (often shading income by 20–30%).
3. Test your repayments at an interest rate about 3% higher than today’s (APRA serviceability buffer).

Used well, these loans can get you into a home sooner. Used badly, they can be expensive and increase mortgage stress.

Lenders analyse 6–12 months of business and personal bank statements to estimate income.

1. Where bank statement and BAS-based loans fit in the documentation landscape

1.1 Full-doc vs alt-doc vs low-doc in one minute

Australia now has three broad income documentation pathways for home loans:

• Full-doc – standard payslips or two years of tax returns and financials. Usually the cheapest rates and highest LVRs.
• Alt-doc – stronger than old-school low-doc, using things like bank statements, BAS and accountant letters to prove income.
• Low-doc – a niche, higher-cost space where you self-declare income with minimal supporting evidence. Often needs a larger deposit.

For a deeper comparison of these pathways, see Choosing the right documentation pathway for your next home loan.

Bank statement and BAS-based loans sit firmly in the alt-doc bucket. They’re not a free pass; they’re just a different way of proving the same thing: consistent, sustainable income.

1.2 Who these loans are really for

These products mainly suit:

• Sole traders, contractors and consultants.
• Company directors and partners taking drawings instead of tidy wages.
• Small business owners whose latest tax returns undervalue their current income.
• Borrowers who are behind on lodging returns, but have strong, provable turnover.

They’re less suitable for:

• People with highly seasonal or volatile income where the last 6–12 months were unusually strong or weak.
• Borrowers trying to stretch to their absolute borrowing limit in a rising-rate environment.

If you’re a high-income professional or business owner, you may qualify for sharp full-doc terms instead; see Home loans for high‑income self‑employed professionals and owners for that angle.

2. How bank-statement home loans actually work

2.1 What lenders look for in your bank statements

Most alt-doc lenders want 6–12 months of:

• Business trading account statements – to see your turnover and expense patterns.
• Personal account statements – to confirm drawings or salary, and your living expenses.

They’re scanning for:

• Regular, explainable deposits linked to your business activity.
• Consistency – stable or rising income, not big unexplained drops.
• Clean separation of business and personal spending where possible.
• No recurring dishonours, overdrawn periods or payday-style loans.

If you’ve been mixing business and personal spending in one account, now is the time to separate them. As we explain in other guides, keeping separate accounts for 3–6 months usually improves lender confidence in your income and living-expense story.

2.2 How they turn deposits into an income figure

Lenders don’t just take your gross deposits at face value. A common conservative method is:

1. Total your eligible business deposits over 6–12 months.
2. Exclude one-offs (asset sales, refunds, transfers between your own accounts).
3. Annualise the result (if using less than 12 months).
4. Apply a business expense factor or shade – often 20–30% off the top.
5. Divide by 12 to get a monthly income figure for serviceability.

Different lenders use different formulas. Some may:

• Use the lowest 3 months in the period instead of the average.
• Cap income growth year-on-year.
• Cross-check against BAS or accountant letters.

A specialist broker’s job is to match your situation to a lender whose methodology works in your favour without pushing the boundaries.

2.3 Worked example: bank-statement-based income

Assume you run a consulting business and want an alt-doc mortgage using bank statements.

• Business deposits last 12 months: $240,000 (after removing one-offs).
• Average per month = $240,000 ÷ 12 = $20,000.
• Lender assumes 30% expenses and 70% margin (this is just an example):
  • Assessed income = $20,000 × 70% = $14,000 per month.

Now the lender stress-tests your loan:

• Loan amount: $900,000.
• Actual interest rate: say 6.5% p.a. (alt-doc, indicative only).
• Assessment rate (with ~3% APRA buffer): 9.5% p.a..
• Term: 30 years.

At 9.5%, 30 years, repayments are about $7,560 per month.

With assessed income of $14,000/month, the lender still has to factor in:

• A standard HEM living-expense benchmark (based on your household).
• Any personal and business debts with personal guarantees.

If after all of that, your net surplus is strong enough, you pass serviceability. If not, you’ll need to reduce the loan size, clear debts, add a co-borrower or wait for stronger trading figures.

For a broader view of how banks scrutinise your financials, see How Banks Read Your Business Financials Before a Home Loan.

BAS turnover figures help lenders assess income for self-employed borrowers.

3. How BAS-based home loans work

3.1 Why lenders like BAS

A BAS-based home loan uses your Business Activity Statements as a primary proof of income. Lenders like BAS because:

• They’re lodged with the ATO, so they’re harder to manipulate.
• The GST turnover figure is a clean measure of sales.
• They show your business activity over time (usually quarterly).

This is particularly useful if your most recent tax returns don’t yet reflect a big upswing in revenue, or if you’ve changed structures and only have one full year of returns.

3.2 Turning BAS into serviceable income

A common BAS-based method is:

1. Take 4 quarters of BAS (12 months) and total the GST turnover.
2. Annual GST turnover ÷ 12 = average monthly turnover.
3. Apply an industry-appropriate expense ratio (e.g. 40–70%).
4. The remainder becomes your assessed monthly income.

Some lenders will:

• Use 6 quarters if your income is lumpy.
• Compare BAS turnover with your bank deposits, looking for consistency.
• Cap growth if this year is dramatically higher than last year’s tax return.

3.3 Worked example: BAS-based income

Say you’re a tradie company director. Your last 4 BAS show GST turnover of $440,000 over the year.

• Average monthly turnover: $440,000 ÷ 12 ≈ $36,667.
• Lender assumes a 60% expense ratio (labour, materials, overheads).
• Assessed income = $36,667 × (1 – 60%) = $14,667 per month.

You want a $1,000,000 loan on a 30-year term, alt-doc rate say 6.9% p.a. (illustrative):

• Assessment rate at +3% buffer = 9.9% p.a..
• Repayments at 9.9%, 30 years ≈ $8,820 per month.

With assessed income of $14,667/month, the lender then deducts living expenses and other commitments. If the surplus is adequate, the BAS-based assessment passes.

For more on using tax data in home loan applications, see How to Use Tax Returns to Prove Income for Your Home Loan.