ACCC Merger Regime Changes 2026: Mandatory Notification Thresholds, Exemptions, and Bright Line Tests Explained

Changes were recently announced to Australia’s new ACCC mandatory notification regime, including introducing new notification thresholds, filing triggers, and exemptions.

These changes were foreshadowed on 15 October 2025 when the Government announced its intention to make amendments to the merger regime, including refined notification thresholds, expanded exemptions for low-risk activities such as ordinary course land acquisitions, and other practical adjustments, before the regime’s full commencement on 1 January 2026.

The amendments were finalised and registered on 18 December 2025 through the Competition and Consumer (Notification of Acquisitions) Amendment (2025 Measures No. 1) Determination 2025, which directly amends the original Competition and Consumer (Notification of Acquisitions) Determination 2025.

Australia’s new mandatory merger control regime is in force as of 1 January 2026. These reforms, enacted through the Treasury Laws Amendment (Mergers and Acquisitions Reform) Act 2024, represent the most significant change to Australian merger law in decades, shifting from a voluntary notification system to a mandatory and suspensory regime administered by the Australian Competition and Consumer Commission (ACCC).

The regime is designed to provide greater transparency, enable earlier intervention in potentially anti-competitive mergers (including creeping acquisitions), and bring Australia into closer alignment, in some respects, with international best practice.

Businesses involved in mergers, acquisitions, or strategic investments must now carefully assess whether their transactions trigger mandatory notification obligations. Non-compliance risks rendering the acquisition void and attracting substantial penalties. The Government intends to later make practical adjustments to the automatic voiding provisions that still preserve the incentives for parties to notify proposed mergers.  The details of how this will be achieved are not known at this stage.

Changes Applying from 1 January 2026

The core elements of the mandatory and suspensory regime commenced on 1 January 2026 include:

• Mandatory Notification: Acquisitions of shares, units, or assets with a sufficient Australian nexus that meet prescribed monetary or other thresholds must be notified to the ACCC before completion.

• Suspensory Effect: Completion is prohibited until the ACCC grants clearance or a waiver is obtained.

• Control-Based Share and Unit Acquisitions: Notification is required where the acquisition confers sole or joint control and satisfies one of the monetary thresholds. These include: (i) the combined Australian revenue of the acquirer group and target is at least $200 million, and either the target's Australian revenue is at least $50 million or the global transaction value is at least $250 million (large merged firm threshold); or (ii) the acquirer group's Australian revenue is at least $500 million (very large acquirer) and the target's Australian revenue is at least $10 million.

• Business Asset Acquisitions: Acquisitions of all or substantially all assets (note, this is not a defined concept) of a business are subject to similar thresholds.

• Serial Acquisitions: The ACCC may aggregate relevant prior acquisitions over a three-year period, subject to carve-outs for low-value or divested assets (refined in the December 2025 amendments).

• Exemptions and Waivers: A range of exemptions apply, including significantly expanded categories for ordinary course land transactions, financing and securitisation arrangements, external administrations, and superannuation transfers. A formal waiver process is available for transactions below thresholds or otherwise low-risk.

• Phased Review Process: Fast-track clearance for clearly non-contentious matters, with statutory timelines and filing fees.

Changes Applying from 1 April 2026

Certain additional notification triggers, deferred to allow preparation time, will commence on 1 April 2026:

• Non-Control Share Acquisitions – Bright Line Tests: Mandatory notification for specified increases in voting power, even where control is not acquired. Key triggers include:

  • Voting power rising from ≤20% to >20% (with limited application to widely held/listed entities).

  • Voting power rising to ≥50% from a lower holding. These tests disregard standard minority shareholder protections in many cases.

• Discrete Asset Acquisitions: Lower, differentiated thresholds apply to acquisitions of assets that do not comprise all or substantially all of a business (e.g., acquirer Australian turnover ≥ $200 million and transaction value ≥ $200 million, or ≥ $500 million and ≥ $50 million).

These measures ensure the regime captures material creeping acquisitions and significant partial asset deals while remaining proportionate.

The Competition and Consumer (Notification of Acquisitions) Amendment (2025 Measures No. 1) Determination 2025

The Amendment Determination, registered on 18 December 2025, implemented the refinements foreshadowed in the October 2025 announcement. It amends the principal Determination of 30 June 2025 based on stakeholder consultation and the ACCC’s experience during the voluntary transitional phase (July–December 2025).

Purpose

To make the regime more targeted, risk-based, and workable in practice by reducing unnecessary regulatory burden on low-risk transactions while preserving robust protection against anti-competitive mergers.

Key Contents

• Refined monetary thresholds distinguishing “business” from “discrete” asset acquisitions.

• Exclusions from serial acquisition aggregation for low-revenue or divested assets.

• Bright line voting power tests for non-control share acquisitions (deferred to 1 April 2026).

• Significantly expanded exemptions, particularly for ordinary course land acquisitions (e.g., development, retail, office use), staged quasi-land rights, broader financial market transactions, and minority protections in small private companies.

• Technical adjustments to waiver processes, fee settings, and consideration calculations.

Commentary

Treasury’s intention was  to introduce a “fast, stronger and simpler merger system” within Australia’s merger laws.  The new regime will provide the ACCC with greater visibility of a broader range of transactions however there is some doubt as to whether the new regime will be “fast” and “simpler”.

Businesses should consider how domestic transactions or global deals with an Australian connection will be affected by the new regime.  Competition analysis will vary between jurisdiction, particularly so with USA antitrust law. 

For a confidential discussion about how the new merger regime may affect your business, please contact Opportuna Legal. Early assessment is key in the initial months.

This is general information only and not legal advice. Seek tailored guidance for specific transactions.