A ban on pricing below cost was implemented under the 1987 Groceries Order based on the premise that loss leading used in multi-product retail pricing distorts competition and exploits consumers in the short run, while driving a more concentrated structure and reducing welfare in the long run. Loss leading is examined for multi-product retailers selling in imperfectly competitive
market niches with imperfect consumer information. We develop a theoretical argument in a simple two-stage framework that illustrates how loss leading on a subset of products is an equilibrium
outcome of price competition that leaves overall welfare equal to that observed under laissez faire.
