Estimated reading time: 7 minutes
TL;DR
- 28 April 2026 is the Q3 BAS deadline (January–March quarter). It is one of the ATO’s most-watched dates.
- From 1 April 2025, the ATO extended its refund-withholding window from 14 to 30 days, giving it more time to investigate high-risk lodgements.
- Approximately 3,500 small businesses were shifted from quarterly to monthly BAS reporting in 2025 due to inconsistent compliance history.
- The ATO now matches over 1 billion transactions annually using AI and small discrepancies trigger automated audit flags.
- Audit activity creates direct underinsurance and uninsured liability risk that most business owners haven’t considered.
Table of Contents
What is the ATO's current crackdown on BAS lodgements?
The ATO has significantly increased scrutiny of Business Activity Statements in 2025–26, targeting businesses with inconsistent GST reporting, late lodgements, and irregular cash flow patterns. If you lodge late, under-report, or have discrepancies between your BAS and other ATO data, you are now far more likely to trigger an automated review and potentially a full audit.
The April 28 deadline isn’t just an administrative date. It’s one of the ATO’s most active enforcement windows of the year.
Why is April 28 significant for BAS compliance?
28 April 2026 is the Q3 BAS due date covering activity from 1 January to 31 March 2026. It applies to most quarterly reporting businesses (those with GST turnover under $20 million).
This is significant for several reasons:
- It’s the third quarter deadline of the financial year, and by now, the ATO has a full picture of your reporting pattern
- The ATO proactively targets businesses that have already shown inconsistency earlier in the year
- It falls just 10 weeks before EOFY, non-compliance here rolls directly into year-end exposure
What changed in 2025 - the ATO's new enforcement powers
Two material changes came into effect in 2025 that significantly increase the ATO’s ability to scrutinise BAS lodgements:
1. Extended refund-withholding window (from 1 April 2025)
From 1 April 2025, the ATO extended its notification period for withholding BAS refunds from 14 days to 30 days. This means the ATO now has up to 30 days to review and potentially retain your GST refund if it considers the lodgement high-risk — doubling the previous window.
The ATO can retain a refund if it would be reasonable to require verification of the refund amount. High-risk indicators include fraud likelihood, evasion, or inconsistency with other ATO data.
2. Forced shift to monthly reporting
From 1 April 2025, the ATO began issuing notices to approximately 3,500 small businesses, advising that their tax period had been shortened from quarterly to monthly reporting. This is not a legislative change; it is the Commissioner exercising existing powers under the GST Act to shorten a taxpayer’s reporting cycle based on the taxpayer’s non-compliance history.
If you’ve received such a notice, monthly lodgement is now mandatory. Missing monthly deadlines (the 21st of each month) will escalate your risk profile further.
How the ATO finds you: data matching at scale
The ATO now matches over 1 billion transactions annually using AI and machine learning. This includes data from banks, payment platforms, payroll software, superannuation funds, and third-party reporting.
Common triggers for automated audit flags include:
| Red flag | What the ATO sees |
|---|---|
GST reported doesn’t match bank deposits | Revenue may be understated |
Input tax credits unusually high vs turnover | Overclaiming likely |
Payroll reported in STP doesn’t match BAS PAYG | Discrepancy in obligations |
Super lodged late or understated | Workers at risk, director liability flag |
BAS lodged consistently late | Pattern of non-compliance |
What does an ATO audit mean for your insurance?
This is the part most accountants don’t discuss, and most insurers don’t proactively flag.
Underinsurance risk
Many business owners set their Business Interruption cover based on revenue figures that haven’t been reviewed in years. If an ATO audit reveals your actual turnover is higher than what’s recorded on your policy — due to unreported cash sales, GST errors, or payroll discrepancies — your BI cover may no longer reflect your real trading position.
A business interruption event, whether caused by fire, flood, or a cyber incident, could result in a claim calculated against an outdated, lower revenue figure, not what your business actually earns. That gap is real, and it falls on you
Audit cost cover
ATO audits are expensive even when you’ve done nothing wrong. Accounting fees, legal representation, and the time cost of responding to information requests can run into thousands of dollars. Tax Audit Insurance (sometimes included in a Business Pack) covers these professional fees. Many SMEs don’t know they have this option.
Directors and officers exposure
If the ATO pursues a director personally via a Director Penalty Notice — for PAYG withholding or superannuation liabilities that were understated in BAS — that becomes a personal liability matter, not just a business one. Directors can be held individually responsible for company tax debts, and the costs of defending that position add up quickly. It’s worth checking whether your current cover extends to this kind of exposure. Directors & Officers Liability can either be a standalone cover or included in a Management Liability policy, depending on your circumstances.
BAS compliance and insurance: the connection most businesses miss
| ATO compliance issue | Insurance risk created |
|---|---|
Late or missed BAS lodgement | Audit costs, potential DPN → Management Liability |
GST revenue understated | Underinsurance on Business Interruption policies |
PAYG withholding errors | Director Penalty Notice → Management Liability |
Super underpayment flagged in BAS data | Workers Comp remuneration base discrepancy |
Refund withheld (30-day window) | Cash flow gap → Business interruption if coincides with incident |
What should you do before April 28?
- Lodge on time or confirm agent extension eligibility today
- Cross-check your BAS figures against bank statements and STP data before submitting.
- Review your Business Interruption sum insured. Does it reflect your actual declared revenue?
- Ask your broker about Tax Audit Insurance. It’s low-cost and often overlooked.
- If you’ve had prior late lodgements, speak with your accountant about remediation before the ATO flags you for monthly reporting.
Frequently asked questions
- When is the Q3 BAS due date in 2026?
28 April 2026. This covers business activity from 1 January to 31 March 2026. Businesses lodging through a registered BAS or tax agent may be eligible for an extension. - What changed about ATO BAS scrutiny in 2025?
Two material changes took effect in 2025: the ATO extended its refund-withholding window from 14 to 30 days (from 1 April 2025), and it began shifting approximately 3,500 non-compliant small businesses from quarterly to monthly GST reporting. - How does the ATO detect BAS discrepancies?
The ATO matches over 1 billion transactions annually using AI and machine learning, cross-referencing BAS data with bank records, STP payroll reports, super lodgements, and third-party data sources. - What insurance covers an ATO audit?
Tax Audit Insurance covers the professional fees (accounting, legal) incurred during an ATO audit. It is often available as an add-on to a Business Pack policy. Ask your broker if your current policy includes this. - Can a BAS error lead to a Director Penalty Notice?
Yes. If BAS lodgements understate PAYG withholding or superannuation obligations, directors can become personally liable via a Director Penalty Notice. Management Liability insurance provides coverage for this type of claim. - What is underinsurance risk from an ATO audit?
If an audit reveals your actual revenue is higher than what you’ve declared in insurance policies (particularly Business Interruption), your insured figures are out of date. You may receive a significantly reduced payout if a claim arises. - What is the penalty for late BAS lodgement?
The ATO applies a Failure to Lodge (FTL) penalty. For small entities (under $10M turnover), this is $313 per 28-day period, up to a maximum of $1,565. Larger entities face higher multiples. - What is the difference between quarterly and monthly BAS reporting?
Quarterly reporting (due 28 October, 28 February, 28 April, 28 July) applies to most SMEs with GST turnover under $20 million. Monthly reporting (due the 21st of each following month) is mandatory for larger businesses and can be imposed on smaller businesses with poor compliance history. - Does the ATO’s extended refund window affect me?
If you regularly claim GST refunds (e.g. you have significant input tax credits), the ATO can now withhold your refund for up to 30 days while it investigates. This can affect cash flow — worth factoring into your working capital planning. - What is Operation Protego?
Operation Protego is an ATO campaign targeting GST refund fraud, including fake ABNs and inflated BAS lodgements. It is part of a broader suite of ATO compliance campaigns active in 2025–26.
Related guides
Don't let a BAS review expose an insurance gap
The ATO crackdown is real and it creates insurance risks most business owners haven’t considered. Pocket can review your Business Interruption cover, check if Tax Audit Insurance is right for you, and make sure your declared figures are accurate before EOFY.
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With Pocket is a licensed insurance broker (AFSL 491165). This article is general in nature and does not constitute financial or legal advice. Always consult a qualified adviser for guidance specific to your circumstances.
Sources: ATO.gov.au, Walsh Accounting, EEA Advisory, Australian Accountants.
