We re-examine tacit collusion under a simple punishment rule in which firms match any lower price by their rivals, but otherwise leave their prices unchanged. We provide conditions under which this simple rule sustains collusion and is credible. Provided competition is imperfect, collusion can...

We investigate the nature of price competition among firms that produce differentiated products and compete in markets that are limited in extent. We propose an instrumental variables series estimator for the matrix of cross price response coefficients, demonstrate that our estimator is...