The Australian Taxation Office has released guidance clarifying when and how entities must correct errors in their global and domestic minimum tax filings, setting out amendment timeframes, lodgment procedures, and the limits of what can be changed after a return is submitted.

RF Report

The Australian Taxation Office (ATO) issued new guidance on Amending a global and domestic minimum tax assessment and Globe Information Return (GIR) on 31 March 2026.

Check if an amendment is needed 

To correct mistakes in relation to the global and domestic minimum tax, entities may need to:

  • amend a prior return or assessment, or
  • include the correction in the current year’s return.

For computational mistakes, entities may need to amend one or more of the following prior:

  • GloBE Information Return (GIR)
  • Australian IIR/UTPR tax return (AIUTR) assessment
  • Australian DMT tax return (DMTR) assessment.
  • If the error does not affect the amount of the top-up tax liability, there is no need to amend the assessment

Mistakes that may need to be fixed include where an entity has:

  • misclassified an item of income or tax expense
  • forgotten to include an amount
  • erroneously applied an exemption
  • made data entry mistakes.

When there is no need to adjust or amend a return

Not all errors or adjustments require correcting a tax return. For example, an assessment does not need to be amended if the error does not affect the amount of a top-up tax liability. But a GIR can be corrected for any error, not just ones which affect the top-up tax liability.

In some cases, the global and domestic minimum tax rules require adjustments to be made in the current year calculations in respect of certain errors or adjustments that relate to earlier years. In these cases, any additional top-up tax liability is reported in the current year tax return. Examples of these adjustments include those in respect of prior period accounting errors, or adjustments in respect of changes in prior period income tax liabilities.

For further details, refer to the Minimum tax law. There is no need to amend the prior period tax returns for these adjustments. The four-year amendment period does not apply when making these adjustments in the current period.

Statutory amendment period

The law sets out certain time limits for amending an assessment.

For Australian Income Inclusion Rule (IIR) tax and Australian Undertaxed Profits Rule (UTPR) tax, amendments must be made by the later of:

  • Four years after the designated local entity (DLE) or designated filing entity (DFE) have given the ATO the multinational enterprise (MNE) group’s GloBE Information Return (GIR)
  • Four years after the entity or its DLE have given the ATO the Australian IIR/UTPR tax return for the relevant group entity.

For Australian Domestic Minimum Tax (DMT), amendments must be made by the later of:

  • 4 years after the entity, the designated local entity (DLE) or designated filing entity (DFE) have given the ATO the MNE group’s GIR
  • 4 years after the entity or its designated local entity have given the ATO the Australian DMT tax return for the relevant group entity.

A GIR is given to the ATO when the entity or its designated local entity lodges it with the ATO electronically. For this purpose, the law also treats a GIR as being given to the ATO at the time a foreign ultimate parent entity or designated filing entity lodges it with a foreign government agency. The following conditions must be met:

  • The foreign government agency has a Qualifying Competent Authority Agreement with Australia.
  • The GIR is lodged on time with the foreign agency.
  • The entity or its designated local entity provide the ATO with a foreign lodgment notification.

Amend a combined global and domestic minimum tax return (CGDMTR)

Amendments can only be made by the original lodging entity. For example, a DLE lodges the combined global and domestic minimum tax return (CGDMTR) on behalf of all the group entities in Australia. Subsequently, it is discovered that information in the CGDMTR relating to two of the group entities requires amending. In this case, only the DLE can amend the CGDMTR on behalf of these two group entities because it had lodged the original CGDMTR for them.

The following information provided in the original CGDMTR cannot be amended:

  • Capacity of lodging entity, that is, switching from a group entity to DLE or DLE to group entity. Adding or removing a group entity.
  • Identifiers of the lodging entity, including tax file number (TFN), Australian business number (ABN), ATO reference number (ARN) and name.
  • Identifiers of group entities, including TFN/ABN/ARN, name and business address.
  • Reporting period of the return.

All validations applicable on the original are applicable on the amendment.

After lodging the amended CGDMTR, the lodging entity will receive a lodgment success notification and a transaction ID. An amended notice of assessment (NOAA) and statement of account (SOA) (if applicable) will be issued. The relevant group entity can make a payment if a liability occurs as a result of the amendment.

Amend a GloBE Information Return (GIR)

An amendment to the GIR follows the same process as lodgment of the original GIR. Like the CGDMTR, an amendment can only be made by the original lodging entity.

The GIR XML Schema design is structured in five unique parts:

  • FilingInfo = Part 1.1 to 1.2 of the GIR
  • General Section = Part 1.3 of the GIR
  • Summary = Part 1.4 of the GIR
  • Jurisdiction Section = Part 2 and Part 3.1 to 3.4.2 of the GIR
  • UTPRAttribution = Part 3.4.3 of the GIR.

When amending a GIR, the FilingInfo must be included (as this is mandatory for any original lodgment and subsequent amendment). However, only the relevant part (or parts) of the GIR subsequent to the FilingInfo which are actually being amended need to be included. This means that the full GIR does not need to be lodged on an amendment — only the FilingInfo and the relevant amended part.

In amending any relevant part of the GIR, entities should ensure to correctly complete the DocSpec Type by indicating an updated DocRefID, the correct CorrDocRefID and updating the DocTypeIndic accordingly to indicate that the relevant part is an amendment.

All validation rules that are applicable on the original lodgment will likewise be applicable on the amendment.

Any amendment to the GIR will also indicate a potential new exchange of the GIR with the relevant signatories’ jurisdictions of the GIR Multilateral Competent Authority Agreement (MCAA).

The status of the amendment will follow the same process as the original lodgment. A validation report will be returned to ATO online services once the GIR has been processed by the ATO’s internal systems. Allow up to 3 days for the GIR to be processed.

How to lodge an amendment

CGDMTR or GIR amendments can be lodged using: