Australia’s new merger regime takes effect, forcing big deals into ACCC approval process

From New Year’s Day, big business in Australia can no longer quietly buy rivals and close deals without first going through the competition regulator.

A sweeping overhaul of merger laws that took effect Jan. 1 has introduced a mandatory approval system for many acquisitions, replacing a decades-old, largely voluntary regime and giving the Australian Competition and Consumer Commission (ACCC) power to halt or unwind deals that proceed without clearance.

The change marks the most significant shift in merger control in roughly 50 years and is expected to reshape how companies in sectors from groceries and real estate to mining and digital platforms pursue growth.

Under the new framework, parties to acquisitions that meet specified monetary and turnover thresholds must notify the ACCC and are prohibited from completing the transaction until the watchdog signs off. The regime is mandatory and suspensory—meaning closing before approval, known as gun-jumping, can lead to multimillion-dollar penalties and, in some cases, a deal being declared void.

The government says the reforms, legislated in the Treasury Laws Amendment (Mergers and Acquisitions Reform) Act 2024, are designed to address rising market concentration and bring Australia into line with major economies that already require prior merger approval.

In a statement outlining the changes, the ACCC said the new system is intended to “identify and prevent anti-competitive acquisitions, while allowing those that do not raise competition concerns to proceed as quickly as possible.” The regulator added that stronger merger laws are needed to ensure “strong competition across the economy, driving dynamism, productivity and restraint on prices for the benefit of consumers and efficient businesses.”

From voluntary to mandatory

Until now, Australia was one of only a small number of advanced economies without compulsory merger notification. There was no standstill obligation: companies could complete deals without approaching the regulator, although they risked later court action under Section 50 of the Competition and Consumer Act if the ACCC believed the result was likely to substantially lessen competition.

Businesses routinely sought “informal clearance” from the ACCC to reduce legal uncertainty, but that process was not required by law and did not bind the courts. The ACCC has long argued that the model allowed too many problematic transactions to escape scrutiny, particularly in digital markets and in industries where powerful firms repeatedly bought smaller competitors.

ACCC chairs Rod Sims and Gina Cass-Gottlieb had both publicly called the old system “no longer fit for purpose,” pointing to consolidation in sectors such as supermarkets, infrastructure and online platforms. A series of government reviews, including Treasury’s competition policy work and the ACCC’s Digital Platform Services Inquiry, recommended stronger tools to deal with mergers that entrench market power over time.

The new regime began operating on a voluntary basis on July 1, 2025, allowing businesses to test the processes. It became compulsory on Jan. 1, 2026. From that date, the ACCC stopped offering informal clearance for transactions that fall within the scope of the new system.

Who has to notify

The rules, detailed in the Competition and Consumer (Notification of Acquisitions) Determination 2025, set several monetary triggers.

Broadly, notification is required when:

• The combined Australian revenue of the parties is at least A$200 million and the target has Australian revenue of at least A$50 million, or the global transaction value is at least A$250 million; or
• The acquiring group has Australian revenue of at least A$500 million and the target has Australian revenue of at least A$10 million.

The law also contains special “serial acquisition” thresholds aimed at roll-up strategies, where a business builds dominance by buying a series of smaller rivals or assets. For medium-to-large firms, notification is required if their combined Australian revenue is at least A$200 million and they have acquired A$50 million or more in Australian revenue over the previous three years in the same or substitutable products. For very large acquirers, with at least A$500 million in Australian revenue, the cumulative trigger is A$10 million.

Very small transactions and acquisitions with no real connection to Australia are excluded from those running totals, but the rules mean a pattern of smaller deals in the same space can now bring the next acquisition into the ACCC’s net.

Global mergers can also be caught if the parties have sufficient Australian turnover and the target is regarded as carrying on business in Australia, even when the deal is primarily offshore.

New test, familiar standard

The underlying legal test for blocking a merger—whether it is likely to result in a substantial lessening of competition—has not formally changed. However, recent amendments clarify that this includes acquisitions that create, strengthen or entrench a substantial degree of market power.

The law explicitly allows the ACCC to consider “the cumulative effect on competition resulting from serial acquisitions over the preceding three years” when assessing a deal. That clarification is aimed at addressing concerns about creeping consolidation that may not be obvious when individual transactions are viewed in isolation.

If the ACCC decides a merger would be likely to substantially lessen competition, it can refuse approval or allow the deal to proceed subject to conditions, such as divesting certain assets or accepting behavioral commitments. Parties that believe the merger would deliver wider public benefits can seek a separate authorization, where the test weighs likely benefits to the public against competition harms.

Timelines, transparency and penalties

The new regime adopts a two-phase review model.

Once a complete notification is lodged, the ACCC has up to 30 business days for an initial Phase 1 review, with the earliest possible decision after 15 business days to allow interested parties time to comment. If the regulator believes further examination is needed, the matter moves to a Phase 2 review of up to 90 business days, with scope for extensions in defined circumstances.

The ACCC has said it expects to decide about 80% of notified acquisitions within 15 to 20 business days, through early Phase 1 approvals or a waiver process for straightforward deals. Parties can apply for a waiver when transactions clearly do not raise material competition concerns, although the information requirements remain substantial.

All notifications, waiver applications and decisions will be published on a new public acquisitions register, increasing visibility of proposed consolidations and the regulator’s reasoning.

Failure to notify a deal that meets the thresholds, or completing such a deal before clearance, is now a civil violation. Corporations face maximum penalties of A$50 million, three times the value of any benefit obtained, or 30% of adjusted turnover during the period of the breach—whichever is highest. In some cases, a court can declare a transaction implemented in breach of the standstill requirement void, or order alternative remedies such as divestiture.

The ACCC has indicated that enforcement of the new notification and standstill obligations will be an early priority.

Supermarkets and land banking in focus

While the general rules apply economy-wide, large supermarkets face additional, sector-specific obligations.

All acquisitions of supermarket businesses by Coles Group Ltd. and Woolworths Group Ltd. must be notified to the ACCC, regardless of size or revenue. Those chains must also notify many land acquisitions even when they fall below general monetary thresholds, including sites with commercial buildings of at least 1,000 square meters of gross lettable area and undeveloped land of at least 2,000 square meters.

The government framed the measures as a response to long-standing concerns about supermarket “land banking”—the practice of acquiring and holding undeveloped sites that could otherwise host competing stores.

In contrast, the regime includes broad exemptions for many routine land transactions by property businesses, such as residential developments, lease renewals and sale-and-leaseback deals, to avoid capturing low-risk activity in real estate and infrastructure.

Critical minerals, tech and deal-making

The new rules are expected to have significant implications for cross-border mergers in critical minerals and resources, where Australia plays a key role as a supplier of lithium, rare earths and other inputs for clean energy and defense industries. Large mining and processing deals with Australian operations will almost always require ACCC notification, in addition to scrutiny under the foreign investment regime.

The serial-acquisition provisions are also relevant for private equity and industry players that pursue roll-up strategies in sectors such as health care, aged care, building materials and software.

Technology and digital platform mergers are another focus. The ACCC’s multi-year inquiry into digital platforms highlighted concerns about “killer acquisitions,” where established players buy nascent rivals or promising technologies before they can grow into effective competitors. The combination of mandatory filing, explicit recognition of entrenchment of market power and cumulative-effects analysis gives the regulator additional tools in that space.

Deal advisers say the new system is likely to lengthen transaction timetables and increase costs, with higher filing fees, more complex conditions in sale contracts and a greater emphasis on regulatory risk. At the same time, they expect robust merger activity to continue, driven by superannuation funds, private capital and overseas investors targeting Australian assets.

With the shift from courtroom litigation to front-end regulatory review, the ACCC is now at the center of decisions about who can buy whom in corporate Australia. How it uses its expanded powers over the next few years—and how quickly it processes the rising volume of filings—will determine whether the regime is seen as a brake on efficient consolidation, a check on entrenched market power, or both.