We explore the difference between explicit and tacit collusion by investigating the impact communication has in experimental markets. For Bertrand oligopolies with various numbers of firms, we compare pricing behavior with and without the possibility to communicate among firms. We find strong...

We explore whether lawful cooperation in buyer groups facilitates collusion in the product market. Buyer groups purchase inputs more economically. In a repeated game, abandoning the buyer group altogether or excluding single firms constitute credible threats. Hence, in theory, buyer groups...