Company Tax Return vs BAS vs IAS: What’s the Difference and When Each Is Due 

Company Tax Return vs BAS vs IAS: What’s the Difference and When Each Is Due 

If you run a business in Australia, understanding your taxation obligations is essential — not just for compliance, but to avoid costly penalties and maintain healthy cash flow. Among the most important tax lodgements to know are the company tax return, Business Activity Statement (BAS), and Instalment Activity Statement (IAS). Although all three are about paying tax, they serve very different purposes, apply to different types of businesses, and have separate due dates. This guide unpacks the difference between company tax return vs BAS vs IAS and explains when each needs to be submitted. 

What Is a Company Tax Return? 

A company tax return — sometimes referred to as an annual company tax return or annual tax return — is a legally required annual filing that all companies registered in Australia must lodge with the Australian Taxation Office (ATO). The purpose of this return is to report the company’s total income, allowable deductions, and final tax liability for the financial year (which runs from 1 July to 30 June).  

This return essentially tells the ATO: 

• How much your company earned during the year, 

• What expenses it incurred, 

• And how much tax is owed (or refundable).  

Who must lodge it? 
All companies (including proprietary limited companies, public companies, and foreign companies doing business in Australia) must lodge an annual company tax return, regardless of profit or loss.  

Company Tax Return Due Date (Key Deadlines) 

What Is a BAS (Business Activity Statement)? 

A Business Activity Statement (BAS) is a periodic tax lodgement that helps businesses report and pay certain tax obligations throughout the year — rather than waiting for the annual company tax return. Most commonly, BAS is used by GST-registered businesses.  

On your BAS, you may need to report and pay: 

• Goods and Services Tax (GST) — what you’ve collected on sales vs what you’ve paid on purchases; 

• Pay As You Go (PAYG) Withholding — tax withheld from employee wages; 

• PAYG Instalments — prepayments towards your annual income tax; 

• Fringe Benefits Tax instalments, fuel tax credits, and other liabilities.  

A BAS is essentially a summary of tax activity occurring in a quarter or month, whereas the annual tax return determines your final tax position for the year. 

BAS Due Dates 

What Is an IAS (Instalment Activity Statement)? 

An Instalment Activity Statement (IAS) is another type of activity statement that looks superficially similar to BAS, but it applies in different situations.  

An IAS is used by: 

• Businesses not registered for GST but that still need to make PAYG instalments towards their income tax liability; 

• Taxpayers who need to report PAYG withholding but don’t meet the BAS requirements; or 

• Smaller entities with no GST obligations but still required to prepay tax during the year.  

In contrast to BAS — which bundles GST with other tax components — the IAS typically focuses on income tax instalments and withholding payments when GST isn’t in the mix.  

IAS Due Dates 

Company Tax Return vs BAS vs IAS: Quick Comparison 

How LodgePro Can Help 

Managing your company tax return, BAS, and IAS obligations can quickly become overwhelming — especially while running and growing your business. LodgePro provides comprehensive accounting and tax support to ensure your compliance is accurate, timely, and stress-free. 

LodgePro supports businesses with the preparation and lodgement of their annual company tax return, ensuring income, deductions, and reporting requirements are handled correctly and in line with ATO regulations. With experienced tax professionals overseeing the process, you can be confident your annual tax return is completed properly and submitted before the company tax return due date. 

In addition to annual returns, LodgePro assists with BAS and IAS lodgements, helping businesses stay on top of GST reporting, PAYG withholding, and instalment payments throughout the year. Structured bookkeeping and regular reporting mean fewer surprises, improved cash flow planning, and reduced risk of penalties for late or incorrect lodgements. 

Beyond compliance, LodgePro provides ongoing financial oversight and advisory support, giving you clarity around your numbers and helping you plan ahead for upcoming tax obligations. The result is smoother reporting, better financial control, and peace of mind knowing your business tax requirements are being managed professionally.