Following our earlier overview of the ACCC’s Merger Process Guidelines, Australia’s new merger control has received legislative refinements that took effect on 16 September 2026.
The changes, introduced through the Treasury Laws Amendment (Strengthening Accountability for Tax Adviser Misconduct and Other Measures) Act 2026, are aimed at reducing legal uncertainty and improving the operation of the system.
While they do not alter the fundamental notification requirements, they provide greater clarity and flexibility for transaction parties navigating the regime.
Key changes
Non-notified transactions are now voidable rather than automatically void
One of the most significant changes relates to acquisitions that meet the notification thresholds but are completed without notifying the ACCC.
Under the amended framework, these transactions are no longer automatically void. Instead, the ACCC may apply to the Federal Court for orders declaring the acquisition void, requiring divestiture or granting other remedies.
This change is intended to provide a more practical enforcement mechanism while maintaining the integrity of the notification system. Businesses should note, however, that the consequences of failing to notify remain significant.
Greater clarity around ‘control’ and ‘associates’
The amendments also clarify the operation of the control exemption by introducing new definitions relating to control and the interests of associates.
The changes are intended to better identify arrangements that likely to confer competitively significant influence, while making clear that ordinary commercial relationships, such as financing arrangements, minority shareholder protections and professional advisory relationships, will not generally be captured.
For businesses assessing whether a transaction triggers notification requirements, these amendments provide welcome guidance on how control will be assessed in practice.
More flexibility for ‘stale’ notifications
Once a transaction has been approved under the new regime, parties will have 12 months to complete the acquisition.
The amendments now allow the ACCC to extend that period by up to six months at a time, where there are reasonable grounds for delay and it remains appropriate to rely on the original notification.
This additional flexibility will be particularly relevant for complex transactions that may face extended implementation timelines due to financing, regulatory approvals or transaction conditions.
What does this mean for businesses?
While these amendments are not a wholesale overhaul of the merger control system, they demonstrate the Government’s willingness to refine the framework as practical issues emerge.
Businesses considering mergers, acquisitions or significant investments should continue to assess notification requirements early in the transaction process and remain alert to further guidance from the ACCC.
As Australia’s merger control regime continues to evolve, obtaining advice early in the transaction lifecycle will be critical to managing regulatory risk and avoiding unnecessary delays.
How we can help
McCullough Robertson’s Competition and Regulatory team is closely monitoring developments under the new merger control regime and can assist businesses in assessing notification requirements, managing ACCC engagement and navigating merger approvals.
If you would like to understand how these changes may affect a proposed transaction, we recommend seeking advice early to identify any notification risks and plan an appropriate engagement strategy.
For expert advice on your next acquisition or to discuss how the new merger regime impacts your business, contact Stephen Iu, Partner at siu@mccullough.com.au.