The purpose of this note is to clarify the relationship between the uniqueness of spot market equilibria and the existence of sunspot equilibria. The framework chosen is a standard, two period, competitive change economy with sunspot-dependent real assets. There is no uncertainty except for sunspots. It is demonstrated by an example with Cobb-Douglas preferences and numeraire assets that sunspot equilibria exist, even though spot market equilibria are unique for all distributions of ex-post endowments that can be reached by using ex-ante asset trade. hence our example demonstrates that the existence of sunspot equilibria does not necessarily rely on an argument based on the multiplicity of spot market equilibria. This is remarkable since sunspot equilibria have often been identified with perfect foresight equilibria where agents' expectations over multiple spot market equilibria are coordinated by some exogenous random event: the sunspot. Clearly sunspots can be used as a coordination device of expectations, but from a more general perspective sunspot equilibria are any equilibria in which the equilibrium allocation depends on some exogenous random event. Our example demonstrates that the latter may well be the case without the former.
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