Overview
For half a century, Australian companies could merge at will and simply inform regulators afterward. That ended January 1, 2026. Now businesses must notify the Australian Competition and Consumer Commission before closing deals that meet certain thresholds—and wait for approval. Miss the requirement and your acquisition is automatically void, with penalties on top.
The shift targets what regulators call 'creeping acquisitions'—serial buyers, especially private equity firms, rolling up competitors one at a time. Australia joins the EU, US, and most developed economies in requiring mandatory pre-merger notification. The ACCC expects to decide 80% of cases within three weeks. The other 20% face deeper scrutiny in a country where regulators blocked major healthcare and toll road consolidations in recent years.
Key Indicators
People Involved
Organizations Involved
Australia's competition and consumer protection regulator with powers to review and block anticompetitive mergers.
Peak body representing Australia's largest companies, advocating for business-friendly policy.
National representative body for the Australian legal profession.
Timeline
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Mandatory Merger Control Takes Effect
ImplementationCore regime launches: qualifying acquisitions now require ACCC pre-approval. Deals closed without clearance automatically void.
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Government Delays Asset Threshold Rules
Policy AdjustmentTreasury announces asset acquisition and control thresholds postponed to April 1, 2026, giving businesses more preparation time.
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Voluntary Notification Period Begins
ImplementationCompanies can voluntarily notify acquisitions under new system during six-month transition period.
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Parliament Passes Merger Reform
LegislativeSenate approves bill with no amendments, ending 50-year voluntary merger review system.
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Bill Passes House of Representatives
LegislativeTreasury Laws Amendment (Mergers and Acquisitions Reform) Bill 2024 clears lower house with four Senate sitting days remaining.
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Treasury Laws Amendment Bill Introduced
LegislativeGovernment introduces merger reform legislation to Parliament; Senate Economics Committee given until November 13 to report.
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Major Healthcare Merger Blocked
EnforcementACCC prevents Australian Clinical Labs' acquisition of Healius, second- and third-largest pathology providers.
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ACCC Opposes Transurban Toll Road Acquisition
EnforcementRegulator blocks Transurban's acquisition of Horizon Roads, citing entrenchment concerns in Victoria.
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Cass-Gottlieb Details Proposed Thresholds
Policy AnnouncementACCC Chair outlines monetary and market-share thresholds at National Press Club, emphasizing focus on 'mergers that matter.'
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Leadership Transition at ACCC
PersonnelGina Cass-Gottlieb succeeds Rod Sims as ACCC Chair, continuing push for merger reform.
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ACCC Chair Sims Launches Reform Campaign
Policy AdvocacyRod Sims publicly calls for mandatory merger clearance regime, arguing Australia's laws are 'flawed' and 'out of step' internationally.
Scenarios
ACCC Becomes More Aggressive, Blocking Wave of Deals
Discussed by: Competition law firms including Gilbert + Tobin, Clayton Utz, and Ashurst analyzing enforcement trends
Armed with administrative approval power, the ACCC significantly increases intervention rates beyond the historical norm. Healthcare consolidation, private equity roll-ups, and supermarket expansions face routine blocks or demanding behavioral undertakings. Deal volume drops as acquirers avoid notification-triggering thresholds. Business groups pressure government for threshold increases and expedited review timelines. The regime's success depends on ACCC resources—if case backlogs develop, the 80% fast-track target becomes fiction.
Steady Implementation, 80% Cleared Quickly as Promised
Discussed by: ACCC guidance documents and regulatory forecasts from White & Case, Norton Rose Fulbright
The ACCC hits its targets: most deals clear in three weeks, intervention focuses on genuinely problematic transactions. Serial acquisition provisions catch private equity firms building healthcare and retail empires but don't chill routine M&A. Foreign investors adapt to dual ACCC-FIRB review. After initial compliance learning curve, the regime settles into predictability. Australia joins the global norm without major disruption—voluntary notification worked informally for decades; mandatory rules simply formalize existing practice.
Thresholds Prove Too Broad, Triggering Reform Pressure
Discussed by: Business Council of Australia and Law Council submissions warn of over-capture risks
The $50 million cumulative acquisition threshold for serial buyers sweeps in immaterial deals, forcing ACCC notification for transactions with zero competitive impact. Small businesses buying competitors for $2-5 million face mandatory filings and delays. Compliance costs hit mid-market M&A disproportionately. Within two years, Parliament raises thresholds or creates categorical exemptions. The April 2026 delay of asset thresholds becomes permanent. Overreach undermines the reform's legitimacy, forcing ACCC to grant waivers routinely—recreating informal discretion the law was meant to eliminate.
Historical Context
US Hart-Scott-Rodino Act (1976)
1976What Happened
The United States pioneered mandatory pre-merger notification with the Hart-Scott-Rodino Antitrust Improvements Act. Before 1976, US antitrust enforcement was purely reactive—agencies challenged deals after closing, often too late to unwind them. HSR required companies meeting size thresholds to notify the FTC and DOJ and wait 30 days before closing. Failure to file brought penalties exceeding $50,000 per day.
Outcome
Short term: Initial business resistance focused on compliance burdens and waiting periods for routine deals.
Long term: Became global template for merger control. Regulators gained ability to investigate before deals closed, dramatically improving enforcement effectiveness. Nearly 50 years later, most developed economies operate similar mandatory notification systems.
Why It's Relevant
Australia's reform follows the HSR playbook exactly: shift from post-transaction challenges to pre-approval, cite enforcement gaps under voluntary system, promise fast clearance for non-problematic deals.
EU Merger Regulation (1989)
1989-2004What Happened
The European Commission gained merger control authority in 1989 as part of building the single market. Before that, member states handled merger review inconsistently. The 1989 regulation created mandatory notification for deals above specified turnover thresholds and suspensory rules—companies couldn't close until cleared. After the Commission lost court challenges in the early 2000s, it reformed the system in 2004 with more rigorous economic analysis.
Outcome
Short term: Businesses adapted to dual-track review: EU-level for large cross-border deals, national authorities for smaller domestic transactions.
Long term: The EU regime became the world's most influential merger control system alongside the US. The 'more economics' approach from the 2004 reform set standards globally. Most countries adopting merger control since 1990 use EU-style mandatory notification with turnover thresholds.
Why It's Relevant
Australia's ACCC explicitly modeled its thresholds and two-phase review process on EU precedent. Cass-Gottlieb's goal: bring Australia from outlier to international norm.
UK Digital Markets Act (2025)
2025What Happened
On January 1, 2025, the UK implemented its most significant competition reform in 20 years. While maintaining a generally voluntary merger regime, the Digital Markets, Competition and Consumers Act created mandatory notification requirements for Strategic Market Status firms acquiring stakes above 15%, 25%, or 50% in targets exceeding £25 million value. The reform raised general CMA review thresholds from £70 million to £100 million and expanded the agency's investigative powers.
Outcome
Short term: The UK carved out a middle path: voluntary notification remains the default, but tech 'gatekeepers' face mandatory pre-approval for acquisitions.
Long term: Test case for targeted mandatory notification focused on specific sectors and firm types rather than economy-wide thresholds. If successful, other jurisdictions may adopt hybrid models.
Why It's Relevant
Australia and UK moved simultaneously toward tighter merger control, but chose opposite strategies. UK targeted Big Tech while preserving voluntary filing. Australia went comprehensive mandatory notification. Both responded to the same concern: voluntary systems let problematic deals slip through.