An Entropy-Based Information Sharing Rule for Asymmetric Information Economies

The possibility to compare information partitions is investigated for economies with asymmetric information. First, we focus on two potentially suitable instruments, the Boylan distance and the entropy, and show that the former does not fit the purpose. Then, we use the entropy associated with the information partition of each trader to construct a partially endogenous rule which regulates the information sharing process among traders. Finally, we apply this rule to some examples and analyze its impact on two cooperative solutions: the core and the coalition structure value.

Blocking Coalitions and Fairness in Asset Markets and Asymmetric Information Economies

This paper analyses two properties of the core in a two-period exchange economy under uncertainty: the veto power of arbitrary sized coalitions; and coalitional fairness of core allocations. We study these properties in relation to classical (static) and sequential (dynamic) core notions and apply our results to asset markets and asymmetric information models. We develop a formal setting where consumption sets have no lower bound and impose a series of general restrictions on the first period trades of each agent. All our results are applications of the same lemma about improvements to an allocation that is either non-core or non-coalitionally fair. Roughly speaking, the lemma states that if all the members of a coalition achieve a better allocation in some way (for instance, by blocking the status quo allocation or because they envy the net trade of other coalitions) then an alternative improvement can be obtained through a perturbation of the initial improvement.