Australia’s Merger Regime Changes Again: Parliament Fine-tunes New M&A Rules

Less than a year after Australia’s new merger regime commenced, Parliament has passed the first significant amendments to the framework. The changes address several practical concerns that emerged during the transition period and provide greater certainty for dealmakers, investors and boards navigating Australia’s new mandatory merger notification system.

Australia’s merger regime remains significantly more interventionist than the system it replaced, but Parliament has recognised the need for greater flexibility and commercial practicality.

The latest amendments provide important clarification around minority investments, reduce the risks associated with inadvertent notification failures and give parties more flexibility when approved transactions are delayed.

What has changed?

On 10 September 2026, Parliament passed changes to Australia’s merger regime in Schedule 4 of the Treasury Laws Amendment (Strengthening Accountability for Tax Adviser Misconduct and Other Measures) Bill (Bill).

The Bill introduces the following key changes, which took effect from 16 September 2026:

• parties that fail to notify transactions (non-notified acquisitions) are no longer automatically void. Instead, the Australian Competition and Consumer Commission (ACCC) must apply to the Federal Court for an order declaring the transaction void, with the Court retaining discretion to determine the appropriate outcome
• the Court has broader remedial powers to address non-notified acquisitions, including divestiture orders and other measures necessary to unwind or remedy transactions where appropriate
• greater certainty for minority investments and governance rights. The legislation narrows the scope of ‘associates’ and clarifies when investors will be regarded as having joint control of a target business
• common commercial protections are less likely to trigger notification obligations, including minority shareholder protection rights, standard governance arrangements and certain arm’s-length financing arrangements
• approved transactions can remain valid for longer. Parties may now seek extensions from the ACCC where an approved acquisition cannot be completed within the standard 12-month period. Multiple extensions of up to six months at a time may be granted, reducing the need for parties to re-notify transactions that are delayed for legitimate commercial or regulatory reasons.

Non-notified acquisitions no longer automatically void

One of the most controversial aspects of the original regime was the treatment of transactions that parties failed to notify under the new merger regime.

Under the original legislation, a notifiable acquisition that proceeded without complying with the notification requirements was automatically void from the beginning of the transaction. This applied regardless of whether the failure to notify was deliberate or accidental. As a result, there were concerns that completed transactions could be void, creating uncertainty not only for the parties to the transaction but also for lenders, employees, suppliers and other stakeholders.

Parliament has now replaced that automatic voiding mechanism with a court-supervised ‘voidable’ model. A non-notified acquisition is no longer automatically void from the beginning, meaning it had no legal effect. Instead, the new regime creates a voidable regime such that the ACCC must apply to the Federal Court for an order declaring the transaction void, with the Court retaining discretion not to make such an order where it considers that outcome undesirable.

The Court may also make alternative remedial orders, including divestiture orders and other measures designed to address the consequences of the acquisition. While the legislation does not prescribe when the Court should exercise its discretion, the Explanatory Memorandum suggests this may occur where voiding would cause significant harm to innocent third parties or where the vendor no longer exists.

To support the new framework, the Federal Court may grant injunctions while the ACCC investigates or pursues a non-notified acquisition, allowing assets and businesses to be preserved until the proceedings are resolved. The amendments also allow affected parties to seek orders dealing with the consequences of a voiding order, providing a mechanism to address practical issues that arise after a transaction has been completed.

Importantly:

• the amendments apply to acquisitions put into effect on or after the Bill commences
• automatic voiding will continue to apply in certain circumstances, including where a notified transaction is implemented where the ACCC has rejected approval, or while still under ACCC review or after an ACCC approval has become stale.

While the amendments introduce greater certainty, they do not reduce the importance of compliance. Transactions that are required to be notified but are implemented without ACCC approval or waiver remain voidable, unlawful and continue to expose parties to significant penalties.

Greater certainty for minority investments and governance arrangements

The amendments also address concerns regarding the treatment of minority shareholdings and investor rights.

When the new regime was introduced, the interaction between the concepts of ‘control’ and ‘associates’ created uncertainty about whether ordinary commercial arrangements could trigger notification obligations. In particular, private equity investors, infrastructure investors and joint venture participants expressed concern that standard shareholder protections and governance rights could be treated as giving them control, even where the investor had no practical ability to influence the target’s strategic direction.

The amendments redefine who will be treated as an ‘associate’ for the purposes of the control exemption and introduce a narrower approach to assessing joint control. In particular, the legislation excludes a range of ordinary commercial arrangements from automatically creating an association, including minority shareholder protection rights, dividend policy arrangements, standard shareholder and governance agreements, and certain arm’s length financing arrangements. The amendments also give the Minister power to prescribe additional classes of rights, agreements and arrangements that should be excluded from the analysis as markets evolve.

By narrowing the circumstances in which parties may be regarded as jointly controlling a target, the reforms reduce the risk that passive investors and minority shareholders will be captured by the notification regime solely because they hold customary investor protection or governance rights. In practical terms, this creates a more targeted notification framework focused on acquisitions that are capable of giving an investor genuine influence over a business’s strategic commercial decisions.

Greater flexibility for delayed transactions

The amendments also introduce a practical solution to a common issue facing complex transactions.

Under the new merger regime, an ACCC-approved transaction generally becomes ‘stale’ if it is not put into effect within 12 months of the ACCC determining that it may proceed. Before these amendments, parties facing delays had to re-notify the transaction and restart the approval process.

This created particular difficulties for large or cross-border deals where completion may depend on overseas regulatory approvals, financing conditions or litigation in another jurisdiction.

The amendments allow parties to request an extension from the ACCC before an approval becomes stale. The ACCC may grant extensions of up to six months at a time and multiple extensions where appropriate.

In deciding whether to grant an extension, the ACCC considers factors such as the reason for the delay, whether market conditions have materially changed and whether a fresh notification would be more appropriate.

This change should reduce unnecessary regulatory burden and provide greater certainty for transactions that experience legitimate delays.

What do these changes signal for the future of M&A in Australia?

These amendments represent the first significant recalibration of Australia’s new merger regime. Importantly, they do not signal any retreat from the government’s commitment to stronger merger regulation.

Mandatory notification, ACCC review and enhanced enforcement powers remain central features of the framework. However, the changes demonstrate a willingness to refine the regime where practical experience reveals unintended consequences or disproportionate outcomes.

For businesses and investors, the key takeaway is that merger control is now a fundamental transaction workstream that should be considered from the earliest stages of deal planning. While the latest amendments provide greater certainty and flexibility, they also reinforce the importance of assessing notification obligations, transaction structures and competition risks from the outset.

The new merger regime remains one of the most significant developments in Australian competition law in decades. Businesses that proactively integrate competition law considerations into their transaction strategy will be best placed to navigate this new regulatory environment and execute transactions efficiently and with confidence.