In absence of insurance contracts to share risk, public information is a double-edged sword. On the one hand, it empowers self-insurance as agents better react to shocks, reducing risk. On the other hand, it weakens market-insurance as common knowledge of shocks restricts trading risk. We embody these two faces of information in a single general-equilibrium model. We characterize the conditions under which market-insurance is superior, and then public information - even though costless and precise - is socially undesirable. In the absence of information, however, market-insurance is still underprovided as individuals fail to internalize its general equilibrium benefits.
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