About the supplementary return
We're working to better tailor our engagement with taxpayers under our Top 100 and Top 1,000 justified trust programs for goods and services tax (GST). To facilitate this, in 2025 we introduced the Supplementary annual GST return for large businesses that received a GST assurance rating through a GST assurance review.
The information provided in your supplementary return will enable more tailored and less resource intensive justified trust reviews. The return is straightforward to complete and targeted at understanding your key governance and GST changes during the year. Taxpayers who have achieved high levels of assurance are expected to benefit the most as you've already adopted better governance practices and systems.
Taxpayers who have received a GST assurance report with a GST assurance rating will be required to lodge the supplementary return annually starting from either the:
- 2024–25 financial year, if the report was received on or before 30 June 2024
- 2025–26 financial year, if the report was received between 1 July 2024 and 30 June 2025.
We'll notify you directly if you're required to lodge the supplementary return.
What the supplementary return covers
The Supplementary annual GST return covers:
- how you've actioned recommendations, areas of low assurance or red flags outlined in your most recent GST assurance review (including subsequent interactions with us)
- whether you've maintained or increased your level of GST governance and if you've had any material business or systems changes that impact your GST control framework since your last GST assurance review
- the reconciliation between your audited financial statements and your annualised business activity statements
- whether you've taken any material uncertain GST positions in the period
- whether you've identified any material GST errors in the period and how these have been rectified, and whether you claimed any material amounts of credits in the period that were referable to earlier periods.
You should keep objective evidence to support your responses in the return.
Who needs to lodge a supplementary return
Public and multinational businesses that have received a GST assurance rating through a Top 100 or Top 1,000 assurance review are required to lodge the supplementary return.
You will need to lodge if you received one of the following on or before 30 June 2025:
- Top 100 GST assurance report
- Top 1,000 combined assurance review report with a GST assurance rating
- Top 1,000 GST streamlined assurance review.
If you haven't yet received a GST assurance rating, you're not required to lodge the supplementary return.
When to complete the supplementary return
You'll need to complete the supplementary return starting from the financial year following the financial year you received your GST assurance report.
For example, if you received your first GST assurance rating in a Top 1,000 combined assurance review report issued after 30 June 2025, but before 30 June 2026, you'll need to complete the supplementary return for the 2026–27 financial year onwards.
Examples of lodging a supplementary return
Example 1: GST assurance rating received in September 2025
Titmus Forestry receive an initial Top 100 GST assurance report in September 2025 with their first GST assurance rating. Titmus Forestry is an early December balancer.
As Titmus Forestry receive their report prior to 30 June 2026, they need to complete the supplementary return for the 2026–27 financial year onwards. This is for the period 1 January to 31 December 2026.
End of exampleIf an entity that has previously received an assurance report is no longer a GST reporting entity (that is, they no longer lodge business activity statements) but instead is part of a new GST reporting group, then the new GST reporting group must lodge the supplementary annual GST return. This is when the previously assured GST reporting entity (or entities) contribute 50% or more of the GST throughput reported by the new GST reporting group.
Example 2: changes in GST reporting entity
Attia Media Co. receive a GST assurance rating in their combined assurance review report in August 2022. In April 2024, Attia Media Co. cease being a GST reporting entity when they are acquired by another entity. They are now a member of a new GST group. Attia Media Co. contribute 75% of the GST throughput reported by the new GST group, Saniel Communications.
Despite Saniel Communications not having an initial GST assurance review itself, we advise Saniel Communications that they will need to lodge the supplementary return for the 2024–25 financial year onwards. This is because Attia Media Co. contribute over 50% of the GST throughput reported by Saniel Communications.
End of exampleWhen the supplementary return is due
Taxpayers who have received a GST assurance report with a GST assurance rating will be required to lodge the supplementary return annually starting from either the:
- 2024–25 financial year, if the report was received on or before 30 June 2024
- 2025–26 financial year, if the report was received between 1 July 2024 and 30 June 2025.
The due dates for each financial year are shown in the following tables.
|
Financial year end |
Due date |
|---|---|
|
December 2024 |
21 August 2025 |
|
January, February, March 2025 |
21 November 2025 |
|
April, May, June 2025 |
21 February 2026 |
|
July, August, September 2025 |
21 May 2026 |
|
October, November 2025 |
21 August 2026 |
Table 2: Due dates for the 2025–26 financial year
|
Financial year end |
Due date |
|---|---|
|
December 2025 |
21 August 2026 |
|
January, February, March 2026 |
21 November 2026 |
|
April, May, June 2026 |
21 February 2027 |
|
July, August, September 2026 |
21 May 2027 |
|
October, November 2026 |
21 August 2027 |
Tax periods for return
The Supplementary annual GST return is a further return that we require certain taxpayers to lodge under Division 31 of the A New Tax System (Goods and Services Tax) Act 1999 (GST Act). If you need to lodge the supplementary return, you'll receive a notice under section 31-20 of the GST Act to lodge the return by the specified due date.
Division 31 enables us to require taxpayers to lodge a fuller or further GST return for a tax period or a specified period. We may require information relating to the tax period to which the return relates, or one or more preceding tax periods, or to both.
The supplementary return has a due date that aligns with an existing return due at least 7 months after the end of the financial year.
For instance, for June balancers, the 2025–26 supplementary return will be an additional return for the January 2027 period, due by 21 February 2027. You will need to provide information about the period 1 July 2025 to 30 June 2026.
The supplementary return does not replace any other GST return required. It has no effect on the due dates for any other returns. It also does not affect the 4-year entitlement period to input tax credits under Division 93 of the GST Act, in any way.
Penalties can apply if you fail to lodge the supplementary return on time.
How we use the information you provide
The information provided in your supplementary return will help us:
- assess the extent to which we have confidence that GST has been correctly reported
- determine the level of ongoing investment in GST governance.
Generally, our future engagement with you will depend on a number of factors, including:
- the level of assurance obtained in our most recent GST assurance review
- our monitoring and analytics during the periods between assurance reviews
- the information provided in your return.
The supplementary return collects information relevant to your continued investment in GST governance and correct reporting. It includes the work you've undertaken to address previous ATO recommendations or areas of low assurance or red flags, and whether you have completed the GST analytical tool (GAT) or similar reconciliation for the period.
We'll also use the information to identify and monitor GST risks. We'll differentiate our approach where we identify specific issues that require further engagement with you.
Taxpayers in the Top 100 program
The Top 100 GST assurance program seeks to provide assurance, through the justified trust methodology, that the Top 100 population is reporting and paying the right amount of GST in Australia. Under the program, we gain assurance, or identify areas of GST risk, by engaging with a Top 100 GST reporter (reporter) through a GST assurance review (initial review).
Once the initial review is concluded, we will provide each reporter with a tailored assurance approach that seeks to build upon and leverage as far as possible from previous assurance activities. Our future engagement approach will be based on whether the reporter attains overall high, medium or low assurance.
Overall high or medium assurance GST reporters will be reviewed on a periodic basis at least once every 4 financial years, either via a GST refresh review or a GST assurance check-in, taking a monitoring and maintenance stance during the intervening 3 years. We may conduct targeted assurance activities during this time.
We use the information provided in the Supplementary annual GST return to:
- monitor your GST disclosures and outcomes in the intervening 3 years
- inform the scope and intensity of our GST assurance reviews, including refresh reviews.
The return also provides information for the refresh review period that is relevant to each of the 4 focus areas under justified trust. We'll use this information, in conjunction with our earlier assurance review and what has since been disclosed in real time, to target our focus on the key areas where we need to refresh our assurance base.
Our Top 100 Pre-lodgment disclosure framework sets out our existing expectations for real-time disclosures by Top 100 taxpayers. If you disclose something in real-time that needs to be included in your Supplementary annual GST return, you can provide a brief explanation in the return and refer to the date of the prior disclosure for further context.
Example: taxpayer in the Top 100 program
Layoun Minerals is a Top 100 taxpayer that has had a comprehensive GST assurance review for the 2020–21 financial year and attains an overall high assurance rating with a Stage 2 governance rating and Stage 2 rating for alignment between accounting and GST using the GST analytical tool (GAT). There are no areas of low assurance or red flags in the assurance report.
Our assurance report recommends that Layoun Minerals:
- create a procedure document in relation to issuing recipient created tax invoices
- implement a documented procedure to complete the GAT on an annual basis to understand variances between its financial statements and GST reporting, and
- evidence independent testing of its GST control framework.
Layoun Minerals actively implements our recommendations. It also makes real-time disclosures when applicable in accordance with the Top 100 Pre-lodgment disclosure framework.
When completing the Supplementary annual GST return for the 2024–25 financial year, Layoun Minerals provides the following responses:
- Section B – there were no outstanding actions in relation to recommendations or areas of low assurance or red flags from its most recent GST assurance review (including subsequent ATO interactions) as it has
- implemented a procedure document for recipient created tax invoices
- a documented process to complete the GAT annually, and
- conducted the first phase of internal controls testing in line with its testing plan, with an independent tester conducting the testing of some specific controls and providing a report outlining the findings.
- Section C – during the period the return covers, it considers it meets the criteria to maintain the GST governance rating given in the most recent GST assurance review, based on the criteria set out in our GST governance, data testing and transaction testing guide. There have not been any material business changes or material systems changes that impact its GST control framework since the earlier assurance review.
- Section D – it had completed the GAT for the period the return covers with the following rates provided
- effective GST rate on sales of 10.03%
- effective GST rate on expenses of 9.72%
- net effective GST rate of 9.84%.
It considers that the remaining variance could only be resolved through a transactional-level analysis.
- Section E – it did not take any material uncertain GST positions in the period the return covers.
- Section F – during the period the return covers, it has not identified any material GST reporting errors or claimed material input tax credit amounts referable to earlier periods.
Layoun Minerals retains objective evidence to support its responses.
The information provided indicates that Layoun Minerals has maintained a high level of GST compliance and governance. This enables us to reduce the scope and intensity of the refresh review engagement for the 2024–25 financial year.
Layoun Minerals has disclosed in its Supplementary annual GST return that it completed the GAT for the refresh review period and can readily provide the objective evidence used to support its calculations.
When considering all the relevant information, including their supplementary return, as part of our scoping for the refresh review engagement for Layoun Minerals, we determine that Layoun Minerals is eligible for a GST assurance check-in. We will be able to tailor the review to predominantly rely on the independent tax control testing results and the GAT to evidence and maintain assurance over its reporting for the period.
Information about the scope of GST assurance check-ins for eligible high assurance reporters as part of our tailored approach to maintaining assurance is explained in our guidance, Future GST engagement after initial GST assurance review.
End of exampleTaxpayers in the Top 1,000 program
Under our differentiated approach to combined assurance reviews, we'll assess the responses to the supplementary return to determine the level of intensity for your next GST assurance review. This may result in a less intensive GST assurance review, or we may decide a GST assurance review is not required where:
- you have obtained an overall medium or high assurance rating for GST and a Stage 2 or Stage 3 GST governance rating in your most recent assurance review, with no unresolved ATO or client next actions, and
- the information you provide in your return enables us to maintain confidence that your investment in GST governance is maintained and that GST is correctly reported.
Taxpayers who obtain an overall low GST assurance rating or a Stage 1 GST governance rating will continue to be assured as part of their combined assurance review. However, our review will be tailored based on the assurance already attained and the responses provided in your return.
For taxpayers with significant system changes (for example, implementing a new IT system) since their most recent GST assurance review, generally we would need to consider the impacts of these on GST governance through our assurance programs. Some taxpayers may require specific engagement due to GST risks in their business.
We may take a tailored approach to reviewing objective evidence to support responses in the return as part of a combined assurance review. Our approach will vary based on the assurance previously attained and the responses in the return. For example, this may include reviewing evidence where a taxpayer indicates it has:
- increased a rating to Stage 3 for governance
- addressed recommendations in relation to a specific risk identified in the earlier assurance review, or
- GST analytical tool (GAT) workpapers.
Example: taxpayer in the Top 1,000 program
Timlin Manufacturing is a Top 1,000 taxpayer that has a combined assurance review. They receive an overall high GST assurance rating and a Stage 2 GST governance rating. There are no areas of low assurance or red flags in the assurance report.
Our assurance report recommends that Timlin Manufacturing:
- evidence independent testing of their GST control framework
- document a process to periodically review whether it exceeds the financial acquisitions threshold, and
- implement a documented procedure to complete the GAT on an annual basis to understand variances between their financial statements and GST reporting.
Timlin Manufacturing actively implement all our recommendations from their assurance review.
When completing the supplementary return for the 2025–26 financial year, Timlin Manufacturing provide the following responses:
- Section B – there are no outstanding actions in relation to recommendations or areas of low assurance or red flags relating to our most recent GST assurance review (including subsequent ATO interactions).
- Timlin Manufacturing has implemented documented procedures to complete the GAT on an annual basis and introduced documented processes to regularly review whether the financial acquisitions threshold has been exceeded.
- Timlin Manufacturing has commenced some controls testing in line with our testing plan. However, the testing will not be completed until 2026–27 because the testing occurs over a 3 to 5-year rolling audit period.
- Section C – Timlin Manufacturing considers it meets the criteria to maintain the GST governance rating obtained in the most recent GST assurance review. That is, they consider they have maintained a Stage 2 rating, based on the criteria set out in the GST governance, data testing and transaction testing guide.
- Section D – they have completed the GAT for the period and consider that all variances can be explained. The following rates are provided
- effective GST rate on sales of 9.96%
- effective GST rate on expenses of 9.94%
- net effective GST rate of 9.82%.
They consider that the remaining variance can reasonably be explained by timing differences.
- Section E – Timlin Manufacturing have not taken any material uncertain GST positions in the period the return covers.
- Section F – during the period the return covers, they have not identified any material GST reporting errors or claimed material input tax credit amounts referable to earlier periods.
Timlin Manufacturing retains objective evidence to support the responses.
Based on the information provided in the supplementary return, we are able to assess Timlin Manufacturing's GST compliance position. We determine that they have actioned our recommendations and their responses provide us with confidence that the level of investment in GST compliance has been maintained.
If Timlin Manufacturing is selected for a combined assurance review in the 2025–26 financial year, we would expect to either:
- not undertake a GST assurance review as part of the combined assurance review
- take a tailored approach to reviewing objective evidence to support the responses in the return.
Completing and lodging the supplementary return
2024–25 supplementary return
Download the return for the 2024–25 financial year at Supplementary annual GST return 2025. Use the Instructions to complete the Supplementary annual GST return 2025.
2025–26 supplementary return
Download the return for the 2025–26 financial year at Supplementary annual GST return 2026. Use the Instructions to complete the Supplementary annual GST return 2026.
Lodging the supplementary return
Email your completed supplementary return to SAGR@ato.gov.au.
If additional lodgment methods are available, we'll let you know when we issue your notice to lodge.
You should have objective evidence to support your responses in the return. However, you do not need to provide any documentation when lodging your return. We may ask you for supporting evidence later.
You should be aware that the internet isn’t a secure environment. We don’t control the path of inbound and outbound emails, so we can’t guarantee the privacy of personal information sent by email. You should be aware of this risk if you choose to communicate with us by email and include your personal details.
If you have concerns about providing the lodgment via email, contact us at SAGR@ato.gov.au to discuss alternative options.
More information
If you have any questions about the Supplementary annual GST return, you can email us at SAGR@ato.gov.au.