The ATO Is More Active Than It's Been in a Decade
In early 2026, the ATO publicly stated that a significant portion of Australia's $27.2 billion small business income tax gap is driven by honest mistakes — not deliberate evasion. ATO Assistant Commissioner Angela Allen noted: "Every year we see small businesses run into avoidable issues because they haven't kept accurate records, reported all their income or managed their cash flow effectively."
That's the official line — and it's genuinely meant as a warning, not just a rebuke. But the enforcement environment backing it up is the most aggressive it's been in over a decade.
The 2025–26 Federal Budget allocated $999 million over four years to expand the ATO's audit, data-matching, and debt-collection capabilities, with Treasury expecting this investment to generate over $3 billion in additional receipts by 2029. Director penalty notices have surged, garnishee orders are hitting bank accounts faster than ever, and the ATO's data-matching systems now cross-reference information from banks, payment platforms, and online marketplaces against BAS disclosures — flagging discrepancies in near real time.
When the ATO examined the records of 1,928 small business taxpayers through its random enquiry program, it found that 35% tried to report correctly but made mistakes — usually caused by complexity, not understanding their obligations, or poor record keeping. A further 5% were found to have under-reported income or exaggerated expenses.
The message is clear: most businesses that end up in ATO trouble didn't set out to do the wrong thing. They simply made avoidable mistakes — and those mistakes compound.
Here are the seven most common bookkeeping errors that attract ATO attention, and what you can do to avoid them.
Mistake 1: Falling Behind on BAS Lodgements
Late or missing BAS lodgements are one of the fastest ways to attract ATO scrutiny. Falling behind on BAS and GST obligations remains one of the fastest ways for a business to attract ATO attention — late or incorrect BAS lodgements often stem from incomplete records, GST coded incorrectly in accounting software, or rushing to lodge without properly reviewing figures.
The ATO makes an important distinction: the ATO distinguishes between businesses that lodge on time but struggle with payment (generally treated sympathetically) and businesses that fail to lodge entirely (treated as higher risk).
In practical terms, this means that even if you can't pay the full BAS amount right now, you should still lodge on time — and contact the ATO to discuss a payment arrangement. Ignoring the lodgement entirely is always the worse outcome.
The fix: Set calendar reminders for BAS due dates at the start of every financial year. If you know your books won't be ready in time, engage a registered BAS agent — clients of registered agents are eligible for extended lodgement deadlines, giving you additional time without incurring the Failure to Lodge penalty.
Mistake 2: Mixing Personal and Business Finances
This is the most common bookkeeping mistake, particularly in the early stages of running a business. You might pay for a business expense using your personal card or transfer money back and forth without tracking it properly. Over time, it becomes difficult to separate what belongs where.
The problem isn't just administrative inconvenience. When personal and business transactions are mixed, the ATO's data-matching tools can flag income inconsistencies — particularly when your declared business income doesn't match patterns from bank feeds, payment processors, or industry benchmarks.
The ATO's random enquiry program found that businesses operating well and complying correctly share one consistent characteristic: they have good record keeping practices and undertake regular reconciliation processes, including ensuring cash deposits are included in total sales.
The fix: Open a dedicated business bank account and a separate business credit card if needed. All business income goes in, all business expenses come out. Personal transactions never touch these accounts. This single step makes reconciliation faster, cleaner, and far more defensible.
Mistake 3: Incorrect GST Coding
Every transaction in your accounting software needs to be assigned the correct GST treatment: taxable (10% GST applies), GST-free (no GST, but input tax credits may still apply), or input-taxed (no GST on the sale, no credits on the purchase). Getting this wrong flows directly into an incorrect BAS.
Common GST coding errors include:
- Claiming GST credits on purchases that are actually input-taxed (such as residential rent or financial services)
- Treating GST-free sales (such as basic food, medical services, or exports) as taxable
- Claiming GST on purchases made from suppliers who are not registered for GST
- Coding owner drawings or personal expenses as business expenses with a GST component
The ATO cross-references your reported GST with industry benchmarks and supplier data. Businesses whose GST claims are significantly out of step with their industry without a clear explanation attract closer examination.
The fix: Review your chart of accounts and transaction coding rules in Xero at least annually. When you're unsure about the correct GST treatment of an expense category, ask your bookkeeper or BAS agent before coding — not after lodgement.
Mistake 4: Poor Record Keeping (or None at All)
Unintentional record keeping issues observed in the ATO's random enquiry program include: no source records kept — where bank account statements were used to determine income and expenses instead of being reconciled against them — poorly maintained documentation including partially completed logbooks, faded receipts, and no digital backups, and expenses claimed without the necessary substantiation, particularly motor vehicle, travel and home office expenses.
The ATO requires businesses to keep records for a minimum of five years. This includes invoices, receipts, bank statements, payroll records, asset purchase documentation, vehicle logbooks, and BAS lodgement confirmations.
The ATO notes that poor record keeping can be the result of a lack of business acumen — but it can also be a tax avoidance strategy. When taxpayers deliberately avoid keeping the right records to hide income, they are considered to be participating in the shadow economy. In other words, an absence of records doesn't get you off the hook — it can make the situation look considerably worse.
The fix: Go paperless and systematic. Scan receipts immediately using an app like Dext or Hubdoc (both integrate with Xero), attach them to the relevant transaction, and store everything digitally with automatic backup. You'll never be caught scrambling for a receipt from three years ago.
Mistake 5: Treating ATO Debt as a Low Priority
Treating ATO debt as a low priority is a mistake seen regularly. Many business owners assume the ATO is flexible — and while payment plans do exist, tolerance for inaction has reduced significantly. Ignoring letters or delaying responses often leads to penalties, interest, escalated enforcement action, and unnecessary anxiety.
The numbers make this painfully clear. From 1 July 2025, the General Interest Charge (GIC) on unpaid ATO debt is no longer tax-deductible — a quiet change that significantly increases the effective cost of carrying tax debt. For a company paying tax at 25%, this effectively increases the after-tax cost of ATO interest by approximately 33%.
On top of that, the ATO has dramatically accelerated its enforcement timeline. Director Penalty Notices — which expose company directors to personal liability for unpaid PAYG and super — have surged by 136% in a single year. These aren't reserved for large businesses. Small business directors are being pursued personally for company tax debts.
The fix: If you have existing ATO debt, engage with the ATO proactively — or have your BAS agent do it on your behalf. Payment arrangements are available and are treated far more favourably than silence. And from 1 July 2025, GIC interest is no longer deductible, so carrying ATO debt is materially more expensive than it used to be. The sooner it's resolved, the better.
Mistake 6: Under-Reporting Income or Over-Claiming Deductions
The ATO's five priority risk areas for 2025–26 include private use of business funds treated as deductible expenses, and GST lodgement and payment — especially in the gig economy and trades. The ATO's real-time data matching from banks and payment platforms means discrepancies are flagged within days, not years.
The ATO uses industry benchmarks to compare your reported income and expenses against businesses of similar size and type in your sector. If your profit margins, expense ratios, or GST collected fall outside the normal range for your industry — and there's no clear reason — that inconsistency is a flag.
Common errors that contribute to the small business income tax gap include: underreporting salary and wages from an unrelated entity, underreporting passive income from rental properties, gross interest and dividends, and claiming personal expenses as work-related deductions including car, clothing, travel and gifts or donations.
The fix: Claim what you're entitled to — and nothing more. Document the business purpose of every deduction. For mixed-use expenses like vehicles and mobile phones, maintain clear records of the business-use percentage. If you're uncertain whether something is deductible, ask your bookkeeper or tax agent before claiming it — not after the ATO asks why you did.
Mistake 7: Neglecting to Reconcile Accounts Regularly
A bank reconciliation is the process of matching every transaction in your accounting software against your actual bank statements. When done regularly, it catches errors, duplicate entries, missing transactions, and coding mistakes before they compound into a BAS problem.
Many small businesses assume their records are correct without actually checking them against bank statements — and that's where problems begin. Small mistakes like duplicate entries or missed payments can go unnoticed. Monthly reconciliation is a small habit that saves significant headaches later.
When books aren't reconciled, what happens in practice is this: invoices go unmatched, expenses get duplicated or missed, GST is coded incorrectly on multiple transactions, and by the time BAS is due, the figures are unreliable. The business owner either rushes through the lodgement (and makes errors) or delays it entirely (and cops the FTL penalty).
The ATO's random enquiry program consistently shows that compliant businesses have good record keeping practices and undertake regular reconciliation processes — ensuring that cash deposits are included in total sales and that all transactions are accounted for.
The fix: Reconcile your bank accounts at least monthly — weekly is better. In Xero, bank feeds import transactions automatically, which makes reconciliation a matter of reviewing and approving matched transactions rather than manual data entry. If you're doing this yourself and it's consistently slipping, that's a strong signal to outsource it.
What the ATO Is Specifically Watching in 2025–26
The ATO publishes its small business compliance focus areas quarterly. For 2025–26, the areas receiving heightened attention include:
- GST lodgement and payment — particularly in trades, hospitality, and the gig economy
- Private use of business funds — owner drawings coded as deductible expenses
- Small business CGT concessions — turnover and net-asset test errors
- Shadow economy behaviour — cash transactions not included in reported income
- Payday Super compliance — from 1 July 2026, the ATO has flagged this as a priority enforcement area from day one
The ATO's data-matching systems now cross-reference over a billion transactions annually — including from banks, payment platforms, and online marketplaces — against declared income and BAS figures. Even small discrepancies can trigger an automated flag and prompt an audit or review.
This doesn't mean the ATO is out to get every small business. ATO Assistant Commissioner Angela Allen has stated: "It's all about being transparent about the compliance risks on our radar so small businesses can continue to get it right in 2026. And, where we see deliberate non-compliance including shadow economy behaviours, we will take firmer action."
The message: get it right, engage early, and get support if you need it.
The Simplest Way to Stay Off the ATO's Radar
The ATO's own data from the random enquiry program shows that compliant businesses consistently share three characteristics: they have good record keeping practices, they understand their tax obligations and seek advice when needed, and they have the support of someone who understands their business — such as a registered tax or BAS agent, bookkeeper, or accountant.
None of that requires a large business or a significant budget. It requires consistent habits and the right support — and for most small businesses, a professional bookkeeper costs less per month than the time the owner is currently spending trying to manage books themselves, often badly.
The ATO itself says: "Seeking advice from a registered tax practitioner is one of the most effective ways to avoid common errors and navigate areas of complexity." And in the current enforcement environment, that advice has never been more valuable.
Frequently Asked Questions
How does the ATO know if my income is under-reported? The ATO uses data-matching technology to cross-reference income reported in your BAS and tax return against bank deposits, payment processor data (Stripe, Square, PayPal, EFTPOS), industry benchmarks, and third-party reports. Discrepancies between any of these sources can trigger a review or audit.
What triggers an ATO audit for a small business? Common triggers include: income significantly below industry benchmarks, GST claimed inconsistent with industry norms, large or unusual deductions without clear business purpose, repeated late or missing lodgements, cash-heavy businesses with unexplained transaction patterns, and lifestyle inconsistent with declared income.
If I make an honest mistake on my BAS, will I be penalised? In many cases, the ATO distinguishes between honest errors and deliberate non-compliance. Voluntary disclosure — coming forward before the ATO identifies an error — is treated far more favourably than errors caught in an audit. Your registered BAS agent can help you amend a lodgement and manage the process with the ATO.
Can the ATO hold me personally liable for my business's tax debt? If you operate through a company, yes. Director Penalty Notices (DPNs) allow the ATO to recover unpaid PAYG withholding and superannuation directly from company directors personally — including via personal bank accounts and property. This is one of the most significant risks for small business directors with outstanding obligations.
Clean Books Are Your Best Defence
An ATO audit is disruptive, stressful, and expensive regardless of the outcome. The most effective way to handle one is to never be in a position where your records can't support every figure you've lodged.
Clean, reconciled books — maintained throughout the year by a professional — mean you can respond to any ATO query with confidence. No scrambling, no gaps, no guesswork.
Girl Friday Australia keeps the books for small businesses, sole traders, and tradies across Australia — so your records are always audit-ready, your BAS is lodged on time, and the ATO's growing compliance focus stays firmly someone else's problem.
✅ Registered BAS Agent ✅ Xero Certified Advisor & Gold Partner ✅ 20+ years experience with Australian small businesses ✅ 100% remote, Australia-wide ✅ No lock-in contracts
Get a free quote or book a discovery call — and make sure your books say exactly what they should.