Be nice, unless it pays to fight: a new theory of price determination with implications for competition policy

This paper introduces a simple extensive form pricing game where firms can react to each others’ price changes before the customers arrive. The Bertrand outcome is a Nash equilibrium outcome in this game, but it is not necessarily subgame perfect. The subgame perfect equilibrium outcome features the following comparative static properties. The more similar firms are, the higher the equilibrium price. Further, a new firm that enters the industry or an existing firm that becomes more efficient can raise the equilibrium price.