The 2025-26 financial year ended on 30 June, and if you lodge your own tax return, the ATO's due date is 31 October 2026. For most people that is a routine job. If you are planning to apply for a car loan in the next few months, it is also more than that. Your tax return, the notice of assessment that follows it, and any tax you still owe can all shape how a lender reads your application.
This article walks through the dates the ATO has published, what a notice of assessment actually shows, how an unpaid tax bill or a reported business tax debt can affect a loan application, and a simple checklist to work through before you apply.
The tax return dates the ATO has published
The ATO's published dates for individuals are straightforward, but they depend on how you lodge:
- Lodging yourself: your tax return is due by 31 October. Returns lodged online through myTax are generally processed within 12 business days, according to the ATO.
- Using a registered tax agent: most registered agents have a lodgment program that lets them lodge after 31 October. The ATO says you need to engage the agent before 31 October to be part of that program, including if you are using an agent for the first time or switching agents.
- Prior year returns still outstanding: under the ATO's registered agent lodgment program, individuals and trusts with one or more prior year returns outstanding as at 30 June 2026 have a 31 October 2026 due date for their 2026 return, even through an agent.
- Paying a tax bill: if you lodge your own return between 1 July and 31 October and it results in a tax bill, the ATO says payment is due by 21 November. If the assessment issues after 31 October, payment is due 21 days after it issues.
- Missing the date: the ATO's advice is to lodge as soon as you can. Getting up to date may help you avoid late lodgment penalties and interest on any tax you owe.
Under the agent program, some individuals' 2026 returns are not due until 15 May 2027, with a concessional date of 5 June for returns due 15 May where any payment is also made by then. That flexibility is useful, but it has a side effect for borrowers, covered further down.
What a notice of assessment shows
Once the ATO processes your return, it issues a notice of assessment (NOA). The ATO describes it as the statement explaining how your tax assessment was calculated. It shows the tax on your taxable income, the credit for tax already paid during the year, and the amount you need to pay or the refund you will receive. If your myGov account is linked to the ATO, the NOA arrives in your myGov Inbox.
The ATO also notes that it can review a return after assessment, normally for 2 years and in some circumstances for 4 years, and may increase or decrease the tax payable or refundable in that time.
Why lenders may ask for your tax return and NOA
For employees on a steady wage, payslips and bank statements are usually the main income evidence. Our guide to what lenders check on your bank statements explains that side of it. Some lenders may still ask for a recent NOA, particularly when part of your income comes from overtime, commission, a second job or investments.
For sole traders, contractors and business owners, the picture is different. Many lenders work from your most recently lodged tax return and NOA to confirm what the business actually earns, and some ask for two years. That means the last year you lodged is often the income figure a lender starts from.
This is where the tax agent timing matters. If your 2025-26 return is not lodged until well into 2027, a lender assessing you before then may be looking at your 2024-25 figures. If your business grew over the past year, lodging sooner may put the stronger figure in front of the lender. If the year was weaker, the lender may still ask for it, so it pays to understand your numbers before you apply. If your financials are genuinely not ready, low doc ABN car loans explains how some lenders use other evidence instead, usually at a higher cost.
A tax bill is a debt, and lenders treat it that way
If your NOA shows tax owing, that is a debt with a due date, and lenders commonly ask about outstanding ATO debts on an application. Paying it on time keeps it simple. Leaving it unpaid has costs that are easy to underestimate:
- Interest compounds daily. The ATO applies the general interest charge (GIC) to unpaid tax, calculated daily on a compounding basis, and reviews the rate quarterly.
- It is no longer tax deductible. GIC incurred on or after 1 July 2025 cannot be claimed as a deduction, even where the debt relates to an earlier year.
- A payment plan is still a commitment. The ATO allows eligible people in financial difficulty to pay by weekly, fortnightly or monthly instalments. GIC keeps accruing on a plan, income tax and activity statement debts need separate plans, and falling behind on new obligations can make the full overdue balance payable at once.
From a lender's point of view, a payment plan is a regular outgoing, much like any other repayment, and it reduces the amount left over to service a car loan. Declare it on your application. A lender that later finds an undeclared ATO debt is likely to treat that more seriously than the debt itself.
Business tax debts can appear on credit reports
For ABN holders there is a further reason to deal with overdue tax. The ATO may disclose business tax debt information to registered credit reporting bureaus when all of these criteria are met:
- The business has an ABN and is not an excluded entity, such as a registered charity, deductible gift recipient, complying super fund or government entity.
- It has one or more tax debts, with at least $100,000 overdue by more than 90 days.
- It is not effectively engaging with the ATO to manage the debt.
- It does not have an active complaint with the Tax Ombudsman about the ATO's intent to report.
Before reporting, the ATO sends a written notice of intent to disclose, and the business has 28 days from receiving it to take action. Complying with a payment plan, or having an active objection or review, counts as engaging. The ATO lists the registered bureaus, which include Equifax, Experian and CreditorWatch, and says the information is removed once the debt is paid in full or the business effectively engages.
If you are applying for ABN vehicle finance, a reported tax debt is the kind of detail a commercial lender may see when it checks your business, so it is far better to resolve it, or at least have a compliant plan in place, before you apply. Our guide to how credit scores affect your car loan rate covers the wider credit side.
A refund helps, but it is not income
A tax refund can be a useful boost, but lenders generally assess regular, ongoing income, so a one-off refund is unlikely to count towards your borrowing power. Where a refund can help is on the other side of the ledger: adding it to your savings for a deposit, or using it to clear a credit card or buy now, pay later balance before you apply. Our guide on how much deposit you need for a car loan explains why a larger deposit can widen your options.
If you are an employee whose take-home pay changed with the 2026-27 tax cut, the income tax cut and your borrowing power covers how lenders look at that. Business owners dealing with the new super timing can read what payday super means for your payslip and car loan. If you use a car for work, car expenses and tax in 2026-27 explains the deduction rules.
A checklist before you apply
- Decide how you are lodging. Lodge yourself by 31 October, or engage a registered tax agent before then. If a loan is coming up, ask your agent when they expect to lodge.
- Keep your NOA handy. Download it from your myGov Inbox once it arrives, along with your lodged return.
- Deal with any tax bill. Pay by the due date if you can. If you cannot, contact the ATO early about a payment plan and include the instalments in your budget and on your application.
- Business owners: watch the mail. If you receive a notice of intent to disclose a business tax debt, act within the 28 days.
- Run the numbers. Use our calculators to test repayments, check current car loan rates and compare lenders. If you already have a car loan and your situation has improved, see whether refinancing could lower your costs.
Getting your tax affairs in order will not guarantee any outcome, because every lender applies its own criteria. It does mean the documents a lender asks for are ready, the figures are current, and there are no surprises when your application is assessed.
