Fighting Collusion. An Implementation Theory Approach

A competition authority (CA) has an objective, which specifies what output profile firms need to produce as a function of production costs. These costs change over time and are only known by the firms. The objective is repeatedly implementable if the firms cannot collude and deceive the CA in equilibrium. We identify necessary and sufficient conditions for repeated implementation when firms can only announce prices and quantities. We use these conditions to study when the competitive output is implementable. We extend the analysis to the case when the firms can also supply hard evidence.