The fine is usually the least of it. A late Business Activity Statement (BAS) can attract a penalty, which can be smaller than people fear or may not arrive at all. The real damage is what happens quietly in the background while the statement sits unlodged, particularly if you are a company director.
What happens if you lodge your BAS late?
The ATO can apply a failure to lodge (FTL) penalty of one penalty unit for every 28 days the statement is overdue, up to a maximum of five. From 1 July 2026, a penalty unit is $364, so the ceiling for a small business is $1,820 per statement. Interest runs separately on anything unpaid.
Two details can change that number. It accrues per document, so four late quarterly statements are four separate calculations rather than one. And the penalty is not deductible, so the cost is the full amount rather than the after-tax version.
The ATO also tends to give you a run-up. It says it generally does not apply penalties in isolated cases of late lodgement, and that it will warn you by phone or in writing, and issue a notice to lodge, before applying a penalty. That is not a reason to be casual, but it does mean a single statement lodged a fortnight late is a different situation from a year of silence.
When the penalty usually does not apply
This is the part most articles get wrong. The ATO’s guidance says it generally will not issue a failure to lodge penalty notice for a late activity statement where the lodgement results in a refund or a nil result. There are exceptions: where the penalty was already applied before you lodged, where the document is a third-party data report, and where you are classified as a large withholder.
So a quiet quarter with nothing to report is not usually the expensive one. The statements that hurt are the ones with money attached.
There is also a safe harbour if you use a registered tax or BAS agent. If you gave your agent everything they needed to lodge on time, and their failure to lodge was not reckless or a deliberate disregard of the law, you are not liable for the penalty. It is worth knowing that it exists, and it is worth keeping the email trail that proves when you handed things over.
Interest is the part that keeps growing.
The penalty caps out. Interest does not.
The general interest charge (GIC) applies to unpaid amounts from the original due date, compounds daily, and is reset each quarter. It was 11.43% a year for the July to September 2026 quarter. Since 1 July 2025, it is no longer deductible, which means carrying an ATO debt now costs you the full headline rate with nothing to offset against your taxable income. A payment plan is better than ignoring the debt, but it is no longer a cheap form of finance.
The three-month clock that matters most
If you run your business through a company, this is the section to read twice.
Unpaid GST, PAYG withholding and superannuation guarantee charge can be transferred to directors personally through a director penalty notice (DPN). Which kind of notice you receive depends almost entirely on whether the statement was lodged.
If the BAS reporting the GST or withholding was lodged within three months of its due date, the notice gives you 21 days and a set of options, including paying or appointing an administrator, a small business restructuring practitioner or a liquidator. Those options can remove the personal liability.
If the statement was lodged more than three months late, or never lodged, the notice locks down. Personal liability is fixed, and appointing an administrator or liquidator afterwards does not remove it. Lodging the statement later does not undo it either, because the status is set by what happened at the time.
Note: Lodging and paying are two separate obligations, and the second one is far more forgiving than the first. If cash is tight, lodge on time anyway. It costs nothing and keeps the options open.
Super works on a tighter timetable, so the discipline of paying super on every pay run matters for the same reason. An unlodged super guarantee charge statement can lock down while your GST position is still inside the safe window.
What else the ATO can do
Beyond penalties and interest, an unlodged statement gives the ATO room to act on its own estimate of what you owe. It can issue a notice to lodge, then make an assessment or an estimate without your numbers, which is rarely a version you would have chosen. It can hold refunds and credits owed to you elsewhere and offset them against the debt.
For larger debts, it can also report the business to credit reporting bureaus. This generally applies when an ABN holder owes $100,000 or more, the debt is over 90 days overdue, and the business is not engaging with the ATO. Once a tax debt shows up in a credit file, it affects equipment finance, supplier terms and lending well beyond the tax bill itself. Engaging early is what keeps you out of that category.
If you are already behind
Lodge first. The ATO will not consider a remission request until the outstanding documents are in, so lodging is the step that makes everything else possible. Use your best figures if the bookkeeping is not perfect, and correct them later rather than waiting.
Then deal with payment separately. A payment plan set at a level you can actually sustain is worth more than an optimistic one that defaults in month three.
Next, ask for remission if the delay had a real cause. The ATO publishes the circumstances it is likely to accept, including serious illness, a natural disaster, and being unable to get information from a third party. It also publishes what it is unlikely to accept, and “I was busy with work” is on that list. Evidence matters, so gather it before you write.
After that, the fix is structural rather than heroic. A registered agent can access lodgement concessions you cannot get yourself, and bookkeeping that is reconciled monthly turns lodgement into a short job instead of a dreaded one. Keeping the records that support the numbers current is what makes both possible, and it protects the GST credits you are entitled to claim, including the rules around GST on business vehicle purchases and leases that catch people out.
If you are a sole trader rather than a director, the personal liability risk is different. Still, the tax obligations of working for yourself include the same lodgement deadlines and the same interest.
Work out how many statements are outstanding and how old the oldest one is because that number decides how urgent this is. If it is more than three months and there is a company involved, that is the conversation to have this week. Taxology’s fixed-fee accounting and taxation packages include the ongoing lodgements, which is usually the cheapest way to stop the problem recurring.
This article is general information and does not take your circumstances into account. Penalty and interest rates change, and director penalty outcomes depend on specific facts and dates, so confirm your position with a registered tax agent before acting.