08/08/2026
THE ATO CHANGED THE RULES ON INTEREST — AND SMALL BUSINESS NEEDS TO KNOW
If you’re a tradie or small business owner with an ATO debt, there was an important change from 1 July 2025 that can make that debt more expensive than you might realise.
The ATO charges General Interest Charge (GIC) when tax debts aren't paid on time. In the past, that interest could generally be claimed as a tax deduction.
Not anymore.
From 1 July 2025, GIC and Shortfall Interest Charge (SIC) are no longer tax deductible.
Think about what that means.
If your business owes the ATO money, the ATO can charge interest on that debt — but you no longer get a tax deduction for that interest. It is now a genuine after-tax cost to the business.
And there is another issue we regularly see with sole traders.
Your personal income tax is NOT a business expense.
If you're a sole trader, you and the business are the same taxpayer. The income tax you pay on the profit of the business is your personal tax. The same applies to PAYG instalments towards your personal income tax.
Paying it from the business bank account doesn't suddenly turn it into a business expense.
This matters because if these amounts are sitting in your Profit & Loss as expenses, you may not be looking at the true profitability of your business.
And that's the bigger lesson.
Tax debt isn't just something sitting on an ATO statement. It can quietly eat into your cash, your profit and your ability to move forward.
If you're carrying tax debt, you need to understand exactly what you're paying, what the interest is costing you, whether your accounts are showing the true position, and what your plan is to get the debt under control.
The numbers need to tell the truth.
Because once you can see the true position of the business, you can start doing something about it.