Mandatory Merger Control in Australia 2026, ACCC Notification, Timelines and Director Liability: a Practical Guide for M&A Teams

Australia’s mandatory merger control regime represents the most significant change to the nation’s competition law framework in decades, replacing the long-standing voluntary notification system with a compulsory, suspensory process administered by the Australian Competition and Consumer Commission (ACCC). Since 1 January 2026, every acquisition of shares or assets that meets prescribed control and monetary thresholds must be notified to the ACCC before completion, and closing is prohibited until clearance or a waiver is granted. This guide provides M&A practitioners with a single, actionable resource covering who must notify, the timelines that now shape deal execution, the remedies and waiver process, and the personal liability exposure that directors and officers face under the reformed regime.

TL;DR, What M&A Teams Need to Know About Mandatory Merger Control in Australia Right Now

• Effective date. The mandatory and suspensory merger control regime commenced on 1 January 2026, following a voluntary pilot that opened on 1 July 2025.
• Who must notify. All acquisitions of shares or assets, including legal or equitable interests, must be notified to the ACCC where both the control threshold and the monetary (turnover) thresholds are met.
• Suspensory effect. Parties cannot complete a notifiable transaction until the ACCC grants clearance or issues a waiver. Completing before clearance is a contravention carrying significant penalties.
• Deal timeline impact. Industry observers expect the ACCC review process to add a minimum of 30 business days to deal timetables for straightforward matters, with complex reviews extending considerably further.
• Penalty exposure. Corporate penalties for non-notification or gun-jumping are substantial, and directors and officers face personal civil liability for failures of compliance oversight.
• When in doubt, notify or seek a waiver. The ACCC has published waiver procedures for transactions that clearly do not raise competition concerns, offering a streamlined pathway to clearance.

Background: What Changed in the Merger Control Regime in Australia During 2025–2026?

For over four decades, Australia operated an informal, voluntary merger clearance process. The ACCC could review transactions brought to its attention, but there was no legal obligation to notify and no mechanism to prevent completion before the regulator had finished its assessment. The Australian Government’s 2023 Competition Review identified this as a critical gap, noting that voluntary notification left the ACCC reliant on parties’ willingness to engage and limited its ability to prevent anti-competitive transactions before they occurred.

The Treasury-led reform process culminated in amendments to the Competition and Consumer Act 2010 (Cth), establishing mandatory merger control in Australia through a phased rollout designed to give the market time to adjust.

Legislative Timeline, Key Dates

Purpose and Scope of the New Regime

The ACCC has stated that Australia’s mandatory merger control regime aims to identify and prevent anti-competitive acquisitions while providing a clear, efficient process that supports legitimate deal activity. The regime brings Australia into line with most comparable economies, including the EU, United Kingdom, United States, Canada, and Japan, which already operate mandatory or semi-mandatory notification systems. For deal teams accustomed to the informality of the old process, the shift requires fundamental changes to transaction planning, SPA drafting, board governance, and completion mechanics.

Which Transactions Must Be Notified? Control and Monetary Thresholds Under Mandatory Merger Control in Australia

The new regime casts a wide net. All acquisitions of shares or assets, including legal or equitable interests, must be notified to the ACCC where the control threshold and the monetary thresholds are met. Understanding exactly when notification is triggered is the first compliance decision every deal team must make.

Control Threshold, Practical Tests

Notification is required where the acquirer would, as a result of the transaction, gain the ability to directly or indirectly control or exert material influence over the target’s operations. This is deliberately broad and covers:

• Outright acquisitions. Purchasing 100% (or majority control) of a target entity.
• Minority stakes conferring material influence. Acquisitions of a significant minority shareholding where board appointment rights, veto powers, or other governance mechanisms give the acquirer meaningful influence over competitive conduct.
• Asset acquisitions. Purchasing a business division, key productive assets, or intellectual property portfolios that provide the acquirer with competitive capabilities.
• Creeping acquisitions. Incremental share purchases that, in aggregate, cross the control threshold.
• Options and conditional contracts. Exercising options or completing contracts that, once triggered, confer control or material influence.

Monetary / Turnover Thresholds

Alongside the control test, the transaction must meet monetary thresholds based on the turnover of the parties in Australia. In practical terms, these thresholds are designed to capture economically significant transactions while exempting very small deals. According to the ACCC’s published guidance, the notification obligation applies where the combined Australian turnover of the merger parties, or the turnover of the target business in Australia, exceeds the prescribed levels. Deal teams must calculate turnover using the ACCC’s published methodology, which includes rules on aggregation across related entities and attribution of revenue from associated businesses.

Aggregation and Attribution Rules

A critical practical issue for multinational groups is that the monetary thresholds are assessed on a consolidated group basis. Revenue from all Australian subsidiaries, joint ventures (where control exists), and related bodies corporate is attributed to the acquirer. This means that an overseas parent with multiple Australian portfolio companies may trigger notification even where the individual acquiring entity’s turnover is modest. Early threshold analysis, run at the term-sheet or due-diligence stage, is essential to avoid surprises at signing.

How to Decide: A Practical “Do I Need to Notify?” Decision Flow

For in-house counsel and deal project managers, the following step-by-step framework offers a reliable initial screen. Industry observers suggest running this analysis as soon as a transaction reaches heads-of-terms stage.

1. Identify the nature of the acquisition. Will the transaction result in the acquirer gaining control of, or material influence over, the target business? If no, notification is not required. If yes, proceed to step 2.
2. Calculate the monetary thresholds. Using the ACCC’s published methodology, determine the combined Australian turnover of the parties and the Australian turnover of the target. If neither threshold is met, notification is not required. If either threshold is met, proceed to step 3.
3. Assess whether the transaction falls within any exemption or carve-out. The regime includes limited exemptions (for example, certain internal restructures within the same corporate group). If an exemption applies, notification may not be required, but confirm with competition counsel. If no exemption applies, notification is mandatory.
4. Determine the pathway: full notification or waiver application. If the transaction clearly does not raise competition concerns (no overlapping markets, no vertical relationships of significance), consider applying for an ACCC notification waiver. Otherwise, prepare a full notification.
5. Engage external competition counsel. For any transaction near the thresholds, or involving overlapping markets, obtain specialist advice before signing the SPA.

When to Engage External Competition Counsel

The practical answer is: earlier than you think. Preparing for ACCC merger review involves assembling market share data, identifying competitive overlaps, and drafting the notification, all of which require lead time. Competition counsel should be briefed at the same time as corporate and finance advisors, not after the SPA is finalised. Board papers authorising the transaction should explicitly record that ACCC notification requirements have been assessed and that the proposed deal timeline accommodates the regulatory process.

The ACCC Notification Process, Forms, Timelines, and Suspensory Effect

Once notification is mandatory, the ACCC process becomes the critical path for deal completion. Understanding the mechanics, and their interaction with SPA conditionality, is essential for managing timetable risk.

How to Prepare the ACCC Merger Notification

The ACCC requires a structured notification containing:

• Transaction details. Parties, deal structure, consideration, and completion conditions.
• Market information. Market definitions, market shares, competitor analysis, and supply chain relationships.
• Competition analysis. Horizontal overlaps, vertical relationships, potential foreclosure effects, and any barriers to entry that may be affected.
• Supporting documents. Board papers, strategic plans referencing the transaction, due diligence reports, and relevant internal communications.
• Structural diagrams. Pre- and post-transaction corporate structure charts showing ultimate ownership and control.

Quality of the initial filing directly affects review time. Incomplete or unclear notifications are likely to prompt information requests, extending the ACCC clearance timeline and delaying completion.

ACCC Review Timeline, Statutory Windows and Practical Expectations

The regime establishes statutory timeframes for the ACCC’s initial review, with the ability to extend into a more detailed Phase 2 investigation for complex or contentious matters. Early indications suggest that straightforward, non-contentious transactions are being cleared within the initial review window, while transactions involving horizontal overlaps or concentrated markets are proceeding to extended review.

The suspensory effect is the single most important practical consequence for deal teams. Once a notification is lodged for a mandatory transaction, the parties are legally prohibited from completing the acquisition until the ACCC has either cleared the transaction, accepted enforceable undertakings, or granted a waiver. There is no “deemed clearance”, silence does not equal approval. Completing before clearance (known as gun-jumping) is a contravention that attracts serious penalties.

Remedies, Waivers and Clearance Outcomes

Not every notified transaction will proceed through a full review. The ACCC has established three primary pathways to resolution, and deal teams should understand each when preparing their notification strategy.

When and How to Apply for a Waiver

The ACCC’s waiver process is designed for transactions that clearly do not raise competition concerns, for example, acquisitions in unrelated markets, or where the target’s Australian operations are de minimis. A waiver application is typically shorter than a full notification and is assessed on an expedited basis. According to early commentary, the ACCC has been granting waivers for clearly benign transactions within relatively short timeframes, providing an important safety valve for deal flow.

Key points for waiver applications include demonstrating that the merger parties do not compete in any relevant market, that there are no vertical or conglomerate relationships of competitive significance, and that the transaction does not raise public interest concerns flagged by the ACCC.

Negotiating Undertakings and Timing Impacts

Where the ACCC identifies competition concerns but does not seek to block the transaction outright, it may accept court-enforceable undertakings. These typically involve structural remedies, divestiture of overlapping business units or assets, although behavioural undertakings may be accepted in limited circumstances. Negotiating undertakings extends the review timeline, and deal teams should build this possibility into their long-stop date calculations. The likely practical effect will be that parties need to identify potential divestiture packages early and have them ready as a fallback position during the ACCC review.

Enforcement, Penalties and Director Liability Under Mandatory Merger Control in Australia

The enforcement framework underpinning the new regime carries real consequences for both corporations and individuals. The penalty increases that took effect on 26 March 2026 significantly raised the stakes for non-compliance, making this a governance issue, not merely a transaction-management issue.

Competition law penalties in Australia for merger-related contraventions, including failure to notify, gun-jumping, and provision of false or misleading information in a notification, can be substantial. Corporate penalties are calculated based on the greater of a fixed maximum amount, a multiple of the benefit obtained from the contravention, or a percentage of the corporation’s annual Australian turnover.

Practical Board and Committee Checklist

Directors and officers have a duty to ensure that the corporation complies with the law, and a failure to implement adequate compliance processes for ACCC notification can attract personal civil liability. The following governance actions are recommended:

• Board resolution. Record that the board has considered the ACCC notification requirements for each proposed transaction, and that legal advice has been obtained.
• Delegation framework. Delegate day-to-day responsibility for notification preparation to a named senior executive, with clear reporting lines to the board or a board committee.
• Timeline monitoring. Require regular reports on the status of ACCC review and any information requests, with escalation protocols if clearance is delayed beyond the initial review window.
• Integration controls. Implement hard controls preventing any integration activity, information sharing, coordinated pricing, customer allocation, before ACCC clearance is received.
• Record keeping. Maintain a clear documentary trail of all competition law advice received, decisions made, and notifications lodged.

Insurance, Indemnities and D&O Considerations

D&O insurance policies should be reviewed to confirm coverage for competition law contraventions, including civil pecuniary penalties. Deal-specific indemnities in the SPA should address the allocation of liability for any failure to comply with the notification regime, particularly in cross-border transactions where the overseas parent may bear ultimate responsibility for ACCC notification compliance.

Practical Templates and Checklists for ACCC Merger Notification

Effective compliance with mandatory merger control in Australia depends on having the right processes in place before a deal reaches signing. Deal teams should prepare and maintain the following resources as standing tools, updated for each new transaction:

• ACCC notification checklist. A standardised document listing every required field in the ACCC notification form, the supporting evidence needed, and the responsible team member, pre-populated with standing company information (corporate structure, Australian turnover, market presence).
• Deal timeline template. A Gantt-style timeline mapping SPA milestones against ACCC process steps, including buffer periods for information requests and potential Phase 2 review.
• Board governance checklist. A short-form checklist for company secretaries, confirming that all required board resolutions, legal advice records, and delegation authorities are in place before notification is lodged.
• Waiver request template. A standardised cover letter and supporting-evidence package for waiver applications, pre-formatted to the ACCC’s requirements.

Case Study: A Mid-Market Horizontal Acquisition Under the New Regime

Consider an anonymised example: an ASX-listed industrial services company (“Acquirer Co”) seeks to purchase a privately held competitor (“Target Co”) operating in the same sector across eastern Australia. Both companies have Australian turnover exceeding the prescribed monetary thresholds, and the acquisition would give Acquirer Co a combined market share in excess of 35% in two regional markets.

At the term-sheet stage, Acquirer Co’s in-house counsel runs the threshold calculation and confirms that notification is mandatory. Competition counsel is engaged immediately and begins preparing the notification in parallel with SPA negotiations. The SPA includes an ACCC clearance condition precedent, a 120-business-day long-stop date, interim operating covenants, and a termination right if clearance is not obtained.

The notification is lodged within days of signing. The ACCC identifies the regional market overlap and issues a targeted information request during the initial review period. Acquirer Co provides the requested data promptly and proposes a divestiture of one overlapping depot as a structural remedy. The ACCC accepts the undertaking, and clearance is granted. Total elapsed time from notification to clearance: approximately 60 business days. The deal completes within the long-stop date, and the board minutes record full compliance with the notification regime at every stage.

Key Takeaways and Recommended Next Steps for Deal Teams

Mandatory merger control in Australia is now an operational reality that affects every significant M&A transaction. The following actions should be taken immediately by deal teams, boards, and in-house counsel:

• Embed threshold analysis into deal origination. Run the control and monetary threshold calculation at heads-of-terms stage, before the SPA is negotiated.
• Update SPA precedents. Ensure all SPA templates include ACCC clearance conditions precedent, appropriate long-stop dates, interim covenants, and termination rights for regulatory failure.
• Brief the board. Every board considering an acquisition should receive a competition law briefing note covering notification requirements, timeline impacts, and director liability exposure.
• Prepare standing notification materials. Maintain up-to-date corporate structure charts, Australian turnover data, and market share estimates to reduce preparation time when a transaction is announced.
• Engage competition counsel early. The ACCC notification process is front-loaded, the quality of the initial filing drives the speed of clearance. Early engagement with specialist competition lawyers in Australia is essential.

Sources

1. Australian Competition & Consumer Commission (ACCC), Mergers & Acquisitions
2. ACCC, Why the ACCC Assesses Mergers and Acquisitions
3. Australian Treasury, Competition Review: Mergers
4. Allens, Merger Control Guide
5. Norton Rose Fulbright, Australia’s New Mandatory Merger Control Regime
6. White & Case, Mandatory Merger Control: Notification Waivers
7. Gilbert + Tobin, New Merger Regime: First-Quarter Insights
8. Maddocks, Australia’s New Merger Notification Regime
9. Ashurst, Australian Merger Reforms