Retail price fixity as a facilitating mechanism

Previous theoretical explanations for retail price fixity show that fixed retail prices can be consistent with either competitive or imperfectly competitive behavior. We develop a conceptual model of retail pricing wherein fixed price points are facilitating mechanisms for tacit collusion. A non-cooperative equilibrium in fixed retail prices is supported through credible threats to revert to Nash pricing if cheating is suspected. We test the implications of this model using a two-stage, ordered probit approach in weekly supermarket pricing data. The results show that price fixity does support collusive equilibria among retailers, but other factors may also explain retail price behavior.