It’s widely accepted that, left alone, markets rarely serve the poor. As a result, governments - often influenced by donor support - are inclined to intervene. However, any intervention in markets has an impact far beyond what might be first anticipated. The challenge is to identify appropriate interventions, where the likely gains outweigh the likely costs and potential winners and losers can be identified. Reforms often come unstuck as the likely gainers have limited economic and political capital, whereas the likely losers are strong and well informed.