We consider a mechanism design setting in which agents can acquire costly information on their preferences as well as others’. A mechanism is informationally simple if agents have no incentive to learn about others’ preferences. This property is of interest for two reasons. First, it is a necessary condition for the existence of dominant-strategy equilibria in the extended game. Second, this endogenizes an “independent-private-value” property of the interim information structure. We show that, generically, a mechanism is informationally simple if and only if it satisfies a separability condition that rules out most economically meaningful mechanisms.

Abstract We analyze how interdependencies in financial networks can lead to self-fulfilling insolvencies and multiple possible equilibrium outcomes. Multiplicity arises if a certain type of dependency cycle exists in the network. We show that finding the cheapest bailout policy that prevents self-fulfilling insolvencies is computationally hard, but that the optimal policy has intuitive features in some typical network structures. Leveraging indirect benefits ensures systemic solvency at a cost that never exceeds half of the overall shortfall. In core-periphery networks, it is optimal to bail out peripheral banks first as opposed to core banks.