Monopoly in the UK: what determines whether the MMC finds against the investigated firms?

This paper draws on data from 73 UK Monopolies and Mergers Commission reports on monopoly between 1973 and 1995. It shows that there is a roughly two in three chance that the Commission will come to an adverse conclusion against the investigated firms in a given case. 75–80% of decisions can be explained purely in terms of the market share of the leading firm and knowledge of the broad nature of the alleged anti-competitive practice. An adverse finding is most likely in cases involving exclusive dealing, and least likely where other vertical restraints are involved.