Tournaments are well known to be vulnerable to collusion as shown by the impossibility theorem in Ishiguro (2004), which asserts that efficient effort levels are impossible to be implemented through a collusion-proof contract. However, we argue that this impossibility is a product of simple...

A supplier is known to be subject to opportunism when contracting secretly with downstream competitors, particularly when downstream firms have "passive beliefs." We stress that in many situations, an equilibrium with passive beliefs may not exist and passive beliefs appear less plausible than...