New Year, New MEGs: Competition Bureau Publishes Draft Merger Enforcement Guidelines For Comment

On November 13, 2025, the Competition Bureau (Bureau) published for consultation its draft Merger Enforcement Guidelines (Draft MEGs) setting out its enforcement approach to merger reviews under the Competition Act (Act). The Draft MEGs are intended to replace the existing MEGs, published in 2011 (2011 MEGs), and to update the Bureau's guidance to reflect current enforcement practices and amendments to the merger review provisions adopted in 2023 and 2024. The consultation period for the Draft MEGs will run until February 11, 2026. For a summary of the amendments to the Act's merger review provisions, see our bulletin titled The Evolving Landscape of Merger Review.

Similar to the Bureau's recently released draft Anti-Competitive Conduct and Agreements Enforcement Guidelines (ACCA Guidelines), the Draft MEGs are written in a plain language style and do not represent a seismic shift in the Bureau's enforcement approach. For more on the draft ACCA Guidelines, see our bulletin titled Competition Bureau Publishes Draft Anti-Competitive Conduct and Agreements Enforcement Guidelines for Comment.

Notable revisions in the Draft MEGs are summarized below.

Structural Presumption Insights

Following recent amendments to the Act, a merger is presumptively anti-competitive if it results in an increase in the "concentration index" (the sum of the squares of the market shares of the participants in the relevant market) of more than 100 and either (i) the post-merger concentration index is more than 1,800 or (ii) the parties' post-merger market share exceeds 30%. The Draft MEGs provide the first insights from the Bureau as to its approach to reviewing mergers that trigger the presumption. Where the presumption is triggered, the Bureau will presume that the merger is likely to substantially harm competition, though the Bureau will also consider whether other evidence refutes the presumption. Notably, the Draft MEGs clarify the Bureau's view that the extent of evidence required to rebut the presumption is a sliding scale; the more the threshold is exceeded, the stronger the evidence required. The Draft MEGs do not provide any specific guidance as to when the Bureau will accept that the presumption is rebutted; merging parties would benefit from understanding the type and extent of evidence required.

Pro-Competitive Benefits Replace Efficiencies

Following the elimination of the Act's efficiencies defence, the Draft MEGs introduce a new "pro-competitive benefits" section outlining the circumstances where the Bureau will consider efficiencies in merger reviews. Specifically, the Bureau will consider the pro-competitive benefits of a merger, including certain cost savings or benefits to consumers, where they are "clearly merger specific, substantiated with rigorous and independent evidence, and demonstrably likely to enhance competitive outcomes in a way that benefits Canadians." Where a merger raises significant competition concerns, efficiencies that satisfy these criteria are unlikely to change the Bureau's conclusion regarding harm to competition.

Focus on Technology

The Draft MEGs reinforce the Bureau's emphasis on mergers in emerging and digital markets, including multi-sided platforms (which provide services to and manage interactions between two or more user groups). The Draft MEGs include specific discussions of the Bureau's approach to defining markets in these cases, including addressing direct and indirect network effects.

The Draft MEGs also address how the Bureau will assess anti-competitive effects stemming from mergers involving multi-sided platforms, such as online marketplaces and social media platforms, including the role of network effects, economies of scope or scale, dynamic competition, and unique factors regarding the ability of competitors to enter or expand in the market.

Other Notable Changes

In addition to the above, the Draft MEGs significantly expand the discussion of numerous concepts addressed in the 2011 MEGs, including:

• Bargaining and Bidding Markets: In bargaining markets where terms of trade are determined through bargaining or negotiation, the Draft MEGs make clear that the Bureau will consider the impact of a merger on both bargaining leverage and bargaining power, with the primary focus on how the merger affects bargaining leverage. In bidding markets where contracts are awarded through auctions or similar processes, the Draft MEGs set out a number of factors that the Bureau will consider, including the structure of the bidding process, bid frequency, transparency, and the criteria used to evaluate bids and select the winning bidder.
• New Barriers to Entry and Expansion: The Draft MEGs include an expanded list of identified barriers to entry or expansion, including network effects that increase a product's value as more people use it, learning by doing whereby existing competitors improve products or services based on past experience, access to data as a competitive advantage and access to key inputs needed to become an effective competitor. The Bureau will review these factors when assessing the likely competitive effects of a merger.
• Non-Horizontal Mergers: For non-horizontal mergers, including vertical mergers (mergers between firms at different levels of a supply chain, such as between a manufacturer and retailer) and conglomerate mergers (mergers between firms that are not in the same supply chain, such as a merger involving complements or related products that may be purchased by the same customers), the Draft MEGs make clear that although the structural presumption does not apply, the Bureau is more likely to investigate a non-horizontal merger where the merged firm's share exceeds 30% in the supply of a related product.

Key Takeaways

While not finalized, the Draft MEGs provide valuable insights into the Bureau's approach to merger review following the recent adoption of significant amendments to the Act, including by:

• Reflecting the Bureau's evolving practices and procedures since 2011, as well as significant recent amendments to the Act, while remaining largely consistent with the guidance and approach found in the 2011 MEGs.
• Clarifying key frameworks, including the Bureau's enforcement approach to mergers where the new rebuttable structural presumption is triggered and to pro-competitive efficiencies in merger review following the elimination of the Act's efficiencies defence.
• Highlighting the Bureau's efforts to address digital markets in all of its recent guidance, with specific sections addressing multi-sided platforms and network effects.

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