In a Bertrand-oligopoly experiment, firms choose whether or not to engage in cartel-like communication and, if so, they may get fined by a cartel authority. We find that four-firm industries form cartels more often than duopolies because they gain less from a hysteresis effect after cartel...

Factors facilitating collusion may not successfully predict cartel occurrence: when a factor predicts that collusion (explicit and tacit) becomes easier, firms might be less inclined to set up a cartel simply because tacit coordination already tends to go in hand with supra-competitive profits....