Australia’s merger laws enter a transformative era from 1 January 2026 with the mandatory Merger Control Regime, replacing the voluntary informal clearance process with compulsory ACCC notifications for deals meeting specific thresholds. This overhaul, enacted via the Treasury Laws Amendment (Mergers and Acquisitions Reform) Act 2024, shifts to an administrative model with standstill obligations to prevent anti-competitive deals slipping through undetected. Businesses must notify, wait for clearance, and face void transactions or penalties for non-compliance, aiming for faster scrutiny of high-risk mergers.

Shift from Voluntary to Mandatory Regime
Historically, companies self-assessed merger risks under the substantial lessening of competition (SLC) test, optionally seeking ACCC views to mitigate court challenges. The new regime mandates notification for qualifying acquisitions, with ACCC as primary gatekeeper and judicial review limited to the Australian Competition Tribunal.
Key goals: capture creeping/serial acquisitions, enhance transparency via public registers, and block harmful consolidations early while streamlining benign ones. Voluntary phase ran July–December 2025; full mandatory kicks in January, with statutory timelines from 12 January.
Notification Thresholds Explained
Deals trigger notification if they meet monetary, control, and nexus tests, capturing shares/assets acquisitions. Thresholds tier by acquirer size, with serial acquisition rules for repeat players.
- Medium acquirers: Target revenue ≥$100m; combined ≥$200m; acquirer global ≥$1b.
- Large acquirers: Target ≥$25m; combined ≥$100m; acquirer global ≥$500m.
- Very large acquirers: Target ≥$10m; combined ≥$50m; acquirer global ≥$100m.
Control: 20%+ voting power or material influence; serial adds cumulative revenue from overlapping past deals. Australian nexus: target carries on business here. Exemptions: low-value (<$2m), public markets under 5%, intra-group.
Threshold Tiers at a Glance
Serial thresholds prevent aggregation below radars.
The Notification and Review Process
Pre-notification consultations recommended for complex deals; fees: $15k short-form, $107k long-form (FY26). Short-form for straightforward; long for vertical/conglomerate risks.
- Phase 1: 30 business days post-notification; 15-day no-decision minimum.
- Phase 2: +90 business days if concerns; extensions for remedies.
- Waivers: $8k fee for low-risk (e.g., <5% share); not a process step.
Public register lists details post-notification; standstill voids early closes, penalties to $50m. Tribunal reviews ACCC decisions within 14 days post-clearance.
ACCC Assessment Criteria
Core test: SLC? Factors now emphasise economic evidence, novel harms (e.g., data/killer acquisitions), barriers to entry. Public benefits weighed less; serial history scrutinised.
Interim guidance flags waivers for innocuous deals; full policy post-January.
Implications for Businesses
Serial acquirers (PE, digital platforms, retail) face most scrutiny; timelines stretch 2–6 months, void risks demand planning. Global deals with Aussie nexus notify; exemptions narrow.
Asset deals captured; non-competes banned >12 months post-sale. Strategies: early ACCC talks, waiver pursuits, remedy prep.
Compliance Checklist
- Screen thresholds early, including serial priors.
- Engage pre-notification for waivers/shorts.
- Budget fees, build 30–120 day buffers.
- Document SLC non-issues for Tribunal appeal.
Challenges and Criticisms
Complexity doubts speed/simplicity goals; late tweaks (e.g., April voting changes) spark uncertainty. Small firms gripe fees/burdens; ACCC capacity strains predicted. Teething issues loom, refinements expected 2026.
Global Context and Comparisons
Aligns with EU/UK mandatory regimes but uniquely tiers thresholds, targets serials. US Hart-Scott voluntary akin to old system; Australia now proactive.
Australia’s 2026 overhaul fortifies competition, demands diligence – navigate wisely for seamless deals.

Vineeth T.C. is a news writer and digital content contributor at PageEuropean, covering key developments across New Zealand and Australia. His work focuses on delivering clear, fact-based reporting on current affairs, public policy, business updates, and regional news that matter to readers.