This presentation by the OECD Secretariat was made during the discussion “Ex-post Assessment of Merger Remedies” held at the 22nd meeting of the OECD Global Forum on Competition on 8 December 2023. More papers and presentations on the topic can be found out at oe.cd/eamr. This presentation was uploaded with the author’s consent.

1. Ex-post assessment of
merger remedies
Overview of Background Note
Richard May
OECD Competition Division

2. Section 1: What are they?
• Ex-post assessments of merger remedies use the benefit of time to
review past remedies and see if they were effective
• While linked to the merger, merger remedies are distinct
• Further potential distinction between remedy design and
implementation
• Ex-post assessments of merger remedies come in many forms
– Dedicated large-scale studies
– Part of wider ex-post assessment of mergers
– Individual case study of a merger with remedy
– Broader studies on types of remedies or sectors 2

3. Section 1 continued: Why do them?
• Merger control matters, so important to get merger remedies
right
• Tool to improve performance and understand what works and
what could be improved
– Can also demonstrate effectiveness
• Improve transparency, show accountability and willingness to
learn
• But not without challenges or costs
– Authority and firms
– Perceived reputational risks

4. • Important to identify the purpose of assessment
– Assess if remedy restored competition versus has it been implemented effectively
– Why? Or why not?
• Methods should adapt to the scale and purpose - no “one-size fits all”
• Range of methodological issues used and to consider
– In house staff v external consultants
– Sampling of cases (timing, data, other factors)
– Qualitative and quantitative approaches
Section 2: Methodological issues (1)
4

5. • There can be challenges with data availability
– Most authorities lack information gathering powers
• Encouraging participation from private firms likely key
– Early and transparent communication helpful
– Link with Confidentiality
• Suggestions for potential improved practice:
– Maintain a database of remedies
– Consider potential to collect data through reporting requirements
– Information gathering powers?
– Need to be implemented – guidelines?
Methodological issues (2)
5

6. • Difficult balance between ex-post assessment and compliance
mechanisms
• Reviews to consider if remedies remain appropriate are similar
– Potential to learn lessons but could complicate ex-post assessments
• Ex-post assessments can provide useful intelligence for
enforcement or advocacy, but care is required
• Temptation for further enforcement if remedies ineffective
– Retrospective action rarely possible
– Consider incentives for firms to participate
Section 3: Interaction with other tools

7. • Past studies are available and illustrate ability to improve through
exercise
• Some themes emerge from collective lessons
– But national experience useful too
• Selected examples related to:
– Effectiveness of remedies high but not complete
– Structural investments are preferred, but require care
– Behavioural remedies have risks but there are still best practices
Section 4: Summaries of lessons