Structural presumptions in antitrust law refer to the concept that certain market structures, including high market shares and concentration, may presumptively harm competition and consumers. Once established by competition authorities or courts, the burden of proof typically shifts to the firms which need to rebut these presumptions. The use of structural presumption in antitrust enforcement continues to animate debates among competition authorities, academics and practitioners, reflecting different views on their relevance, application and accuracy when assessing potential anticompetitive practices.
In December 2024, the OECD held a best practice roundtable on "The Use of Structural Presumptions in Antitrust" to explore how the use of structural presumptions may enable competition authorities to simplify complex issues related to market analysis and accelerate the competitive process, while maintaining the required degree of legal certainty to achieve the desired outcome.
This page contains all session information and materials.
KEY TAKEAWAYS
- Presumption limits - While structural presumptions are a good initial indicators for identifying cases to review, high market shares and concentration do not always lead to anticompetitive harm. At the same time, when conditions for applying a structural presumption are not met, there could still be a competition problem.
- Flexible analysis - A flexible approach adopted by competition authorities may be required, where structural presumptions may serve as a starting point for the analysis, followed by a detailed effects analysis on competition using both quantitative and qualitative evidence.
A detailed summary of the discussion and an executive summary with key findings will be issued in 2025.