Ten Months In, the ACCC’s Mandatory Merger Regime Has Found Its First Teeth — and Its First Fixes

For dealmakers, 1 January 2026 marked the biggest change to Australian merger control in decades. From that date, acquisitions that meet the government’s notification thresholds must be notified to the Australian Competition and Consumer Commission, and the parties must wait for approval before completing. The old informal clearance process, where notifying the regulator was optional, is gone.

Ten months on, the data tells a fairly reassuring story for most transactions, with two important caveats: the ACCC has shown it is prepared to say no, and Parliament has already had to soften some of the regime’s sharper edges.

The numbers so far

According to the ACCC’s 2025–26 annual report, between 1 January and 30 June 2026 the regulator received 145 acquisition notifications and 286 applications for notification waivers. Of those notifications, 104 had been approved by 30 June, none had been refused, and four had been sent to a more detailed Phase 2 review. Of the waiver applications, 234 were granted and 14 were not.

Speed has been the headline. The ACCC reported that in the regime’s first three months, Phase 1 approvals took an average of 18 business days against a statutory window of 15 to 30 business days, while waivers were decided in an average of 11 business days. The regulator’s stated aim is to decide around 80% of acquisitions within 15 to 20 business days, through early Phase 1 decisions or waivers.

The waiver pathway, designed for simple deals that clearly raise no competition concerns, has proved far more popular than the government forecast. For corporate advisers, that matters: a refused waiver means the deal must then be formally notified if it meets the thresholds, adding weeks to the timetable.

The first “no”: Coles in Kalgoorlie

The regime’s first refusal came on 1 July 2026, when the ACCC announced that Coles must not proceed with acquiring a lease over a vacant site in Kalgoorlie-Boulder, Western Australia, where it planned a full-line supermarket and a Liquorland store.

Coles had notified the deal in November 2025, during the voluntary transition period, which brought it under the new rules. The ACCC sent it to Phase 2 in January 2026 and ultimately concluded the acquisition would likely substantially lessen competition in grocery retailing in Kalgoorlie. Its reasoning was that a second Coles store was likely to force out one of the town’s two independent full-line supermarkets, removing a competitive constraint on the major chains. Coles has sought review in the Australian Competition Tribunal.

The case is a reminder that the new regime catches more than share and business purchases. Coles and Woolworths must notify acquisitions of supermarket businesses and of interests in land above a certain size regardless of the monetary thresholds, and leases can be “acquisitions” in their own right. Property developers negotiating anchor tenancies with the majors should build ACCC timing into their plans.

The September amendments

On 16 September 2026, three changes to the merger laws took effect in response to industry concern that the regime was over-inclusive and encouraged precautionary filings.

No more automatic voiding. Previously, a notifiable acquisition completed without notification was automatically void, however inadvertent the failure. The ACCC must now apply to the Federal Court for a declaration that a non-notified deal is void. The Court must make the declaration unless doing so would be undesirable, for example because of significant prejudice to innocent third parties, and it cannot weigh the deal’s competition merits in deciding. Deals that were notified but completed before clearance, known as gun-jumping, remain automatically void.

Extensions for stale clearances. ACCC approvals lapse if a deal has not completed within 12 months. Parties can now apply for extensions of up to six months at a time. The extension mechanism does not cover the section 189 letters issued during the 2025 transition period.

A narrower joint-control test. Ordinary minority shareholder protections, standard governance provisions and arm’s-length financing will no longer, by themselves, make investors associates with joint control. Practical influence over operational or financial matters, such as board appointment rights or vetoes over budgets and business plans, is still needed. Crossing the voting-power thresholds can still trigger notification, however, so minority investors are not off the hook entirely.

What boards and buyers should take from it

• Build the ACCC into the timetable. Most clean deals clear in about a month, but a refused waiver or a Phase 2 referral changes that dramatically. The two Phase 2 matters finalised in the first half of 2026 took around eight months, according to analysis by Norton Rose Fulbright.
• Draft conditions precedent carefully. Sale agreements should deal expressly with ACCC approval, waiver refusal, long-stop dates and what happens if a clearance lapses.
• Don’t assume small means safe. Several refused waivers have involved local or regional roll-ups, where national market shares look modest but local competition is thin.
• Revisit shareholder agreements. The narrowed control test helps private equity and minority co-investors, but voting-power thresholds still apply.

The ACCC publishes every notification and decision on its online acquisitions register, which has quickly become essential reading for corporate advisers. With Coles’ challenge in the Tribunal still to be decided, the next few months will show how much deference the regulator’s Phase 2 judgements receive.

This article is general information only and is not legal advice. Readers should seek advice specific to their circumstances.