More changes to ACCC merger regime: what the latest amendments mean for your business

Australia's mandatory and suspensory merger control regime represented a fundamental shift in how acquisitions above defined thresholds are assessed by the ACCC. The regime was introduced by the Treasury Laws Amendment (Mergers and Acquisitions Reform) Act 2024 and has been operative since 1 January 2026.

The regime’s first months of operation have exposed several areas where refinement was needed, most notably the severe consequence of automatic voiding for non-notified acquisitions.

Schedule 4 of the Treasury Laws Amendment (Strengthening Accountability for Tax Adviser Misconduct and Other Measures) Bill 2026 (the Bill) addresses these concerns with targeted amendments to the Competition and Consumer Act 2010 (Cth) (CCA). The Bill passed through Parliament on 10 September 2026 and is awaiting Royal Assent. The changes to the merger regime will commence the day after Royal Assent. 

From automatic void to court-supervised voidable

Under the mergers regime as currently in force, if an acquisition that is required to be notified to the ACCC is not notified and is put into effect, it is automatically void. This is the case regardless of whether the failure to notify was deliberate or inadvertent. The consequences are stark: the acquisition is treated as if it never occurred, with potential flow-on effects for security interests, financing arrangements, employees and third-party rights.

The Bill replaces automatic voiding with a court-supervised model for non-notified acquisitions. Under the new framework:

• Non-notified acquisitions remain stayed and unlawful under section 45AY of the CCA, and civil penalties continue to apply.

• The acquisition is no longer automatically void. Instead, the ACCC may apply to the Federal Court for an order declaring the acquisition void.

• The Court must make the voiding order unless satisfied it would be “undesirable” to do so (e.g. due to harm to innocent third parties, or where the vendor has been wound up and no longer exists).

• There is a six-year limitation period to make such applications to the Court.

Importantly, in considering whether to void an acquisition, the Court is not permitted to have regard to whether the acquisition is likely to give rise to a substantial lessening of competition or to create any public benefits. The Court’s powers are solely concerned with the procedural failure (not notifying), not the substantive merits of the acquisition.

Automatic voiding is retained in limited circumstances: where an acquisition has been notified and the parties complete the acquisition before the ACCC’s decision has been issued; where the ACCC has not approved the acquisition; or where the notification has become "stale" (more than 12 months old).

Extensions to effective 'life' of an ACCC approval

Under the current regime, an ACCC approval becomes “stale” 12 months after the ACCC’s determination, requiring the parties to re-notify if the acquisition has not been completed within that window. This can be problematic for complex transactions – such as schemes of arrangement or those requiring clearance from multiple overseas regulators – where completion may be delayed for various external reasons.

The Bill introduces a new mechanism allowing parties to apply to the ACCC for an extension of an approval of up to 6 months before it becomes stale. Multiple extensions may be sought. The ACCC must consider: 

• whether there are reasonable reasons why the acquisition has not been completed;

• whether there have been material changes to relevant markets since the determination; and

• whether requiring a fresh notification would be more appropriate.

Refined definitions of “control” and “associates”

Under the existing regime, the control exemption in s 51ABS means that acquisitions of a business which do not deliver “control” of the target generally do not need to be notified. An exception applies where significant shareholdings short of legal control may be acquired. The Bill introduces new sections to clarify the scope of the control exemption and the definition of a person’s “associates”, seeking to ensure that acquisitions which are unlikely to confer competitively significant influence over the target are not inadvertently captured.

The Bill adds a series of exclusions where persons are not considered associates merely because:

• Their relevant shareholder agreement confers standard minority shareholder rights: Protecting financial interests, disposing of securities, receiving profit distributions, or entering into governance agreements that are arm's length and reasonable.

• They have professional or business relationships: Providing advice, acting on client instructions for financial products, making a takeover bid, or appointing a proxy without valuable consideration.

The intent is that merely being parties to a standard governance or shareholder agreement is not sufficient to make the parties associates, so long as the agreement does not regulate how shareholders will vote together or cooperate in controlling the entity. 

Control (new section 51ABSA)

The definition of control is substantively unchanged – it remains the capacity to determine the outcome of decisions about a body corporate's financial and operating policies, assessed by reference to practical influence rather than enforceable rights (this test is derived from the Corporations Act 2001 (Cth)). The Bill adds that a person has control if they and one or more "associates" (as defined in new s 51ABSB) jointly have that capacity.

Associates (new section 51ABSB)

A new definition of "associate" has been introduced into s 51ABSB, narrowed from the Corporations Act concept to focus on risks to competition and reduce compliance burden. A person is an "associate" of another in relation to a body corporate if there is a relationship of control between them; they have entered into a relevant agreement for the purpose of controlling or influencing the outcome of decisions about the body's financial and operating policies; or they are acting in concert for that purpose.

What does this mean for your business?

Businesses should be taking the following steps now to prepare for the amended regime:

• Review M&A compliance processes. Non-notified acquisitions remain stayed and unlawful under section 45AY of the CCA, and civil penalties, court-ordered voiding, divestiture and injunctions all remain available to the ACCC. The move to a voidable model tempers the most extreme consequence, but does not remove the obligation to notify or the risks (including penalties) of failing to do so.

• Consider the new extension mechanism for deal timelines. Parties can now apply to the ACCC for up to 6-month extensions before an approval becomes stale, with multiple extensions possible. This is particularly valuable for complex, multi-jurisdictional transactions. The mechanism is available for existing approvals where the ACCC’s determination was made no more than 12 months before commencement.

• Be aware of residual enforcement risks. The ACCC has six years to apply for a voiding order and new injunctive powers under section 77F allow the Court to freeze integration pending ACCC investigation. Even competitively benign acquisitions could be unwound on purely procedural grounds.

The Bill is expected to receive Royal Assent shortly. The changes to the merger regime commence the day after Royal Assent. Businesses should begin factoring these changes into their transaction planning and seek legal advice to ensure compliance with the amended regime.

Please get in touch if you would like to discuss how these changes affect your business and its transactions.