The model of perfect competition is one of the most famous, most important, and most misunderstood concepts in economics. Rather than aiming to be a full-blown model of real-world competitive markets, the perfect competition model isolates the decentralized coordination mechanism inherent in all...

Central banks often use certain concentration indices in their official reports to determine the degree of intensity of competition, of which the most common are the concentration ratio and the Herfindahl-Hirschman index. It is important to emphasize that when calculating the value of these...