Businesses planning mergers or acquisitions in Canada are operating in a more difficult regulatory environment — and the Competition Bureau’s draft Merger Enforcement Guidelines leave a central question about the merger efficiency defence in Canada unresolved.
Senior counsel John F. Rook, KC has co-authored an Intelligence Memo for the C.D. Howe Institute examining what the Competition Bureau’s draft Merger Enforcement Guidelines (MEGs) say about efficiency — and what they leave unanswered. Co-authored with economist Larry Schwartz, a past member of the Competition Tribunal, the memo was published on March 25, 2026.
What the Draft MEGs Say About the Merger Efficiency Defence
Recent amendments to the Competition Act removed the section 96 efficiency defence and introduced a structural presumption: where post-merger market share exceeds 30 percent and the HHI exceeds 1,800, a merger is presumptively anti-competitive. What replaces the efficiency defence — section 93(h), the “any
