How to Use Business Activity Statements (BAS) as Income Proof for Low Doc Home Loans in Australia

For self-employed Australians, securing a home loan can be challenging without the traditional payslips and tax returns that salaried employees provide. Low documentation (low doc) home loans offer a solution, and one of the most effective ways to verify income is through Business Activity Statements (BAS). This comprehensive guide explains how BAS can serve as income proof, what lenders look for, how to calculate your income from BAS, and strategies to strengthen your low doc loan application in 2025.


Understanding Low Doc Home Loans and BAS

Low doc home loans are designed for borrowers who may not have access to standard financial documentation. This includes self-employed individuals, freelancers, contractors, and small business owners whose income can be irregular or not fully reflected in tax returns. Instead of full financials, lenders accept alternative forms of income verification, with BAS being one of the most common.

A Business Activity Statement (BAS) is a form submitted to the Australian Taxation Office (ATO) by businesses registered for Goods and Services Tax (GST). It reports GST collected and paid, as well as other tax obligations like PAYG withholding. Because BAS lodgments are made quarterly or monthly, they provide a near real-time snapshot of business turnover, making them a reliable indicator of income for lenders.

Why Lenders Accept BAS

Lenders view BAS as credible because they are lodged with the ATO, reducing the risk of fraud. Unlike tax returns, which may be prepared annually and can be influenced by deductions, BAS reflects gross business activity. This allows lenders to assess the earning capacity of a business more dynamically. In 2025, with the ATO’s increased digitization, BAS data is more accessible and verifiable, further cementing its role in low doc lending.

Key Lender Requirements for BAS as Income Proof

Not all lenders accept BAS, and those that do have specific criteria. Understanding these requirements is crucial before applying.

BAS Lodgment Period

Most lenders require a minimum history of BAS lodgments to establish income consistency. Typically, you’ll need to provide BAS for the last 12 months, covering four quarterly statements or 12 monthly statements if you lodge monthly. Some lenders may accept as little as 6 months if you have a strong overall profile, but 12 months is standard.

Consistency of Income

Lenders look for stable or increasing turnover. Significant fluctuations may raise concerns, but they can be explained with a letter from your accountant. Seasonal businesses are considered, with lenders often annualizing income based on the most recent BAS periods.

GST Registration and Compliance

You must be registered for GST and up to date with BAS lodgments. Any outstanding BAS or ATO debts can harm your application. Lenders may verify your ATO integrated client account to ensure compliance.

Business Structure

Sole traders, partnerships, companies, and trusts can all use BAS for income verification, but the calculation method varies by structure. Lenders will also consider your ABN and GST registration duration; typically, a minimum of 12 months of ABN and GST registration is required.

Credit Score and Deposit

Low doc loans using BAS often require a higher credit score and a larger deposit—usually at least 20% of the property value. Some lenders may accept 10-15% deposit but with Lenders Mortgage Insurance (LMI). Interest rates may be slightly higher than full doc loans, reflecting the perceived risk.

How to Calculate Income from BAS for Low Doc Loans

Calculating income from BAS is not as straightforward as reading a pay slip. Lenders use specific methods to annualize your business turnover and derive an income figure.

Step 1: Determine Your Gross Turnover

Your BAS includes total sales (G1 on the BAS form) and other income. This is your gross business turnover. For GST-registered businesses, this figure includes GST, so lenders will typically deduct GST to arrive at a GST-exclusive turnover.

Step 2: Annualize the Turnover

If you have 12 months of BAS, the total turnover is already annual. If you have less, lenders may annualize the figures. For example, if you provide 6 months of BAS showing $150,000 in turnover, they may double it to $300,000. However, most lenders prefer actual 12-month data.

Step 3: Apply an Industry-Specific Profit Margin

Lenders do not assume that turnover equals income. They apply a profit margin based on your industry to estimate net income. For example:

• Construction trades: 20-30% of turnover
• Professional services (consulting, IT): 50-70% of turnover
• Retail: 10-20% of turnover

These margins are derived from ATO benchmarks and industry data. The table below shows common industry margins used by lenders in 2025.

Note: These are indicative; actual margins vary by lender and specific business circumstances.

Step 4: Adjust for Add-Backs and Non-Recurring Items

If you have one-off expenses or income, your accountant can provide a letter explaining these. Lenders may add back certain expenses like depreciation, interest, or personal super contributions to increase your assessable income.

Example Calculation

John runs a consulting business and provides four quarterly BAS for the 2024-25 financial year:

• Q1: $55,000 (incl. GST)
• Q2: $60,500
• Q3: $49,500
• Q4: $66,000

Total turnover (incl. GST) = $231,000 GST-exclusive turnover = $231,000 / 1.1 = $210,000

Lender applies a 60% profit margin for professional services: Assessable income = $210,000 × 0.60 = $126,000

John’s borrowing capacity will be based on this $126,000 income.

Tips to Strengthen Your Low Doc Loan Application Using BAS

Even with acceptable BAS, you can take steps to present a stronger case to lenders.

Keep BAS Lodgments Up to Date

Timely lodgment is critical. Any overdue BAS can signal cash flow problems. Set up reminders or work with a bookkeeper to lodge on time. In 2025, the ATO’s online services make it easier to lodge and view your history.

Minimize Fluctuations

While some variation is normal, extreme spikes or drops can worry lenders. If your business is seasonal, provide a letter from your accountant explaining the pattern and demonstrating overall annual stability.

Reduce Business Expenses Before Applying

Since lenders apply a profit margin, reducing unnecessary expenses won’t directly increase your calculated income. However, if you can show that expenses are decreasing (through BAS comparing sales and purchases), it indicates improving profitability, which may encourage lenders to apply a higher margin.

Provide Supplementary Documents

While BAS is the primary document, supporting paperwork can strengthen your case:

• Accountant’s letter confirming income consistency and business viability.
• Bank statements showing business revenue matching BAS figures.
• Notice of Assessment from the ATO for the last financial year, even if income is lower than actual.
• Interim profit and loss statement prepared by your accountant.

Choose the Right Lender

Not all lenders treat BAS the same way. Some specialist low doc lenders are more flexible with BAS calculations and may accept shorter periods or higher margins. A mortgage broker experienced in low doc loans can help match you with a suitable lender.

Common Pitfalls to Avoid When Using BAS for Income Proof

Understanding what can go wrong helps you avoid rejection.

Inconsistent BAS and Bank Statements

Lenders often cross-check BAS figures with business bank statements. If deposits don’t align with reported sales, it raises red flags. Ensure your BAS accurately reflects your banked income.

Large Cash Transactions

If your business deals heavily in cash, lenders may be skeptical since cash income can be underreported. Maintain clear records and consider using electronic payments where possible.

Recent ABN or GST Registration

If you’ve only recently registered for GST, you may not have enough BAS history. Some lenders require 12 months of GST registration, but others may accept less if you have a strong credit score and large deposit.

Mixing Personal and Business Finances

Using the same bank account for personal and business transactions makes it difficult for lenders to verify business turnover. Separate accounts present a clearer financial picture.

Alternatives to BAS for Low Doc Income Verification

If BAS isn’t suitable or sufficient, other low doc options exist.

Accountant’s Letter

A letter from a qualified accountant stating your income can be used by some lenders. This is often combined with BAS or bank statements.

Business Bank Statements

Some lenders accept 6-12 months of business bank statements, analyzing credits to estimate income. This method is similar to BAS but may rely on a higher profit margin assumption.

Asset-Based Loans

If you have significant assets but irregular income, an asset loan may be an option. These loans are based on the value of assets rather than income.

Full Doc with Tax Returns

If your tax returns show sufficient income, a full doc loan offers lower rates and more options. Consider waiting until you can provide two years of strong tax returns.

FAQ

How many BAS statements do I need for a low doc home loan?

Most lenders require the last 12 months of BAS, which is typically four quarterly statements. Some may accept 6 months if you have a strong application, but 12 months is standard to demonstrate income stability.

Can I get a low doc loan if my BAS shows fluctuating income?

Yes, but you may need to explain the fluctuations. Seasonal businesses are common, and an accountant’s letter can clarify that overall annual income is sufficient. Lenders may average the income over the period.

What profit margin will lenders use for my industry?

Lenders use industry-specific benchmarks, often based on ATO data. For example, professional services might be 50-70%, while retail could be 10-20%. The exact margin varies by lender and your business specifics.

Is a low doc loan with BAS more expensive than a standard home loan?

Typically, yes. Low doc loans often have slightly higher interest rates (0.5% to 1% above standard rates) and may require a larger deposit (at least 20%) or LMI. However, they provide access to home ownership for self-employed borrowers who can’t provide full documentation.

Can I use BAS if I’m not registered for GST?

No, BAS is only for GST-registered businesses. If you’re not registered, you’ll need to use alternative income verification methods like accountant’s letters or business bank statements.

References

1. Australian Taxation Office, “Business Activity Statements,” 2025. https://www.ato.gov.au/Business/Business-activity-statements-(BAS)/
2. Mortgage & Finance Association of Australia, “Low Doc Loans: A Guide for Self-Employed Borrowers,” 2025. https://www.mfaa.com.au/low-doc-loans-guide
3. Australian Securities and Investments Commission, “Home Loans for Self-Employed Consumers,” 2025. https://moneysmart.gov.au/home-loans/low-doc-loans
4. Reserve Bank of Australia, “Lending Practices for Self-Employed Borrowers,” 2025. https://www.rba.gov.au/publications/bulletin/2025/
5. Australian Bureau of Statistics, “Counts of Australian Businesses, 2024-25,” 2025. https://www.abs.gov.au/statistics/economy/business-indicators