On 10 September 2026, the Australian parliament passed several long-awaited 'targeted refinements' to Australia's merger control regime. These changes, which have come into effect from 16 September 2026, include:

• a shift from automatic voiding to a court-supervised process to declare non-notified acquisitions void;
• refinements to the concepts of joint control and associates; and
• a new administrative mechanism for extending the period in which approved acquisitions can be put into effect.

These changes represent an important first tranche of adjustments to the regime since it commenced on 1 January 2026, including some changes to address aspects of the new regime that are resulting in significant over-capture of transactions.

Further changes are likely in the near to medium term, in the context of a review of the notification thresholds that is expected after the first 12 months of the regime, and a comprehensive statutory review of the regime slated for late 2028.

In the meantime, we expect further ACCC guidance on various issues, including its approach to notification waivers.

End of automatic voiding and shift to court-ordered voiding for non-notified acquisitions

A controversial feature of the new Australian regime had been that it deemed a notifiable acquisition (one that met the mandatory thresholds) to be automatically void if the parties completed the transaction without first obtaining clearance or a waiver. In practice, this has meant that merger parties and advisers have adopted a conservative position regarding various aspects of the thresholds in circumstances where the effect of getting it wrong has been the transaction being deemed to be void.

The changes sensibly replace automatic voiding with a process that allows the ACCC to seek orders in the Federal Court declaring a non-notified transaction to be void. Importantly, this change is limited to non-notified acquisitions. The existing automatic voiding mechanism will continue to apply where parties complete an acquisition while it remains subject to ACCC review, after the ACCC has blocked a transaction, or more than 12 months after ACCC approval has been granted. The court's existing powers are also preserved, including its ability to impose financial penalties for giving effect to a non-notified acquisition.

When considering an application by the ACCC to void a non-notified acquisition, the court must:

• declare the acquisition void unless it considers that doing so would be undesirable. The government has indicated this may be the case where a voiding declaration would cause significant prejudice to innocent third parties or where the vendor has been wound up and no longer exists;
• not consider whether the acquisition would substantially lessen competition in any market, give rise to public benefits, or whether any public benefits outweigh any detriment. This is intended to preserve the ACCC's role as the primary decision-maker responsible for substantive merger assessments.

Accordingly, where the ACCC chooses to make an application, there is limited scope for the court to not make the declaration, even where the acquisition gives rise to no or limited competitive harm in Australia.

The changes also empower the court, on application by the ACCC, to make any other orders in relation to a non-notified acquisition, including to divest shares or assets. The court also has a new power to grant an injunction, including where the ACCC is investigating whether to seek a voiding declaration. The purpose of this power is to enable the court to pause integration, preserve the target, and/or prevent the acquirer (or another party) from on-selling the target assets or shares.

This is a pragmatic change, recognising that the regime includes ample incentive for merger parties to notify acquisitions that meet the thresholds, including risk of financial penalties and now the prospect of the ACCC seeking orders to have a non-notified transaction declared void, with the ACCC indicating it will be taking such enforcement action.

We hope (and expect) that these changes are only a first step in refining the new merger control regime in Australia… The changes make important practical adjustments to the regime. However, we expect that future reviews will examine aspects of the regime that are resulting in material over-capture in transactions that are being notified to the ACCC."

Clarification of the control exemption: Joint control and associates

The amendments also adjust the meaning of 'control' and who is an 'associate' when considering if there is a scenario that may involve joint control. These changes build on adjustments that were made to the notification thresholds shortly prior to the commencement of the regime to include a minority shareholder protection carve out to the concept of connected entities (an important change when calculating Australian revenue of the parties and their 'connected entities' for the purposes of the notification thresholds).

Currently, transactions that do not result in a change of control are exempt from notification, unless certain voting power 'gateways' are passed. Rather than materially altering the underlying concept of control, the changes have sought to further clarify how the joint control test operates and to narrow the situations in which a person is treated as an 'associate'. In part, this was to address concerns that an associate relationship may arise simply by entry into a shareholders' agreement:

• 'Control' will continue to be assessed by reference to section 50AA of the Corporations Act (Cth). The relevant question is whether the acquirer (alone or together with its associates) has the capacity, in a real and practical sense, to determine the outcome of decisions concerning the target's financial and operating policies. This requires consideration of all relevant circumstances, including the practical influence that may be exercised and the nature of any relationship, arrangement or understanding between the acquirer and its associates. The fact that two parties are associates will not, of itself, establish joint control. It remains necessary to test whether those parties jointly possess the requisite practical capacity to influence the target's financial and operating policies.
• The changes narrow the definition of 'associate' for the purposes of the joint control test. A person will generally only be an associate where: (i) the parties are within the same corporate group; (ii) they have entered into, or propose to enter into, an agreement for the purpose of controlling or influencing the target's financial or operating policies; or (iii) they are acting, or proposing to act, in concert in relation to controlling or influencing the target's policies.

Importantly, the reforms make clear that a person will not become an associate merely because of certain classes of rights or arrangements, including:

• rights to dispose of securities (or control the exercise of such rights);
• minority shareholder protection rights, noting however that these differ from the concept of minority shareholder protection rights which are used in the concept of connected entities;
• dividend policy arrangements;
• arm's-length financing agreements; and
• arm's-length standard shareholder or member agreements relating to governance processes.

Other specific relationships are also excluded, including professional advisory relationships, ordinary client–broker relationships, takeover offers and proxy appointments. To provide flexibility, the Minister has also been granted a power to prescribe classes of rights, agreements or other matters that give rise to, or are excluded from, an associate relationship.

Ability to extend to avoid determinations becoming 'stale'

Another emerging issue, particularly in the context of multi-jurisdictional transactions with complex filing processes in many countries, has been that an ACCC clearance becomes "stale" if the notified acquisition is not put into effect within 12 months. Under the current regime, there was no mechanism to fix this other than the parties submitting a fresh notification. The reforms address this by introducing a mechanism that allows parties to apply in writing to the ACCC for an extension of up to six months.