UCL Department of Economics


Martin O'Connell

Martin O'Connell

martin oconnell

Martin O'Connell - Website


Research interests

Industrial organisation and public economics

Paper title - 'Corrective Tax Design in Oligopoly'

Abstract - We study the design of taxes aimed at limiting externalities in markets characterized by differentiated products and imperfect competition. In such settings policy must balance distortions from externalities with those associated with the exercise of market power; the optimal tax rate depends on the nature of external harms, how the degree of market power among externality generating products compares with non-taxed alternatives, and how consumers switch across these products. We apply the framework to the topical question of taxes on sugar sweetened beverages. We use detailed data on the UK market for non-alcoholic drinks to estimate a model of consumer demand and oligopoly pricing for the differentiated products in the market. We show the welfare maximizing tax rate leads to welfare improvements over 2.5 times as large as that associated with policy that ignores distortions associated with the exercise of market power.


  • Professor Richard Blundell
  • Professor Rachel Griffith
  • Professor Aureo de Paula
  • Professor Pierre Dubois