This paper analyzes a model of self-fulfilling currency attacks, demonstrating that when speculators face small noise in their signals about the fundamentals, there is a unique equilibrium. In contrast to models with perfect information, this model allows for the analysis of policy interventions to prevent currency attacks. The paper shows that the uniqueness of equilibrium arises because the imperfect information structure prevents common knowledge of the fundamentals, leading to a critical state below which currency attacks always occur and above which they never do. The value of this critical state depends on financial variables such as the mass of speculators and transaction costs. The paper also highlights the importance of transparency in monetary policy and its dissemination to the public. The model considers the strategic interaction between the government and speculators in the foreign exchange market, with the government deciding whether to defend or abandon the currency peg based on the proportion of speculators attacking. The analysis shows that the government's decision is influenced by the cost of defending the peg and the proportion of speculators attacking. The paper also discusses the implications of changes in transaction costs, aggregate wealth, and the information structure on the incidence of currency attacks. The results suggest that policies aimed at restoring transparency and common knowledge of fundamentals can help prevent currency crises.This paper analyzes a model of self-fulfilling currency attacks, demonstrating that when speculators face small noise in their signals about the fundamentals, there is a unique equilibrium. In contrast to models with perfect information, this model allows for the analysis of policy interventions to prevent currency attacks. The paper shows that the uniqueness of equilibrium arises because the imperfect information structure prevents common knowledge of the fundamentals, leading to a critical state below which currency attacks always occur and above which they never do. The value of this critical state depends on financial variables such as the mass of speculators and transaction costs. The paper also highlights the importance of transparency in monetary policy and its dissemination to the public. The model considers the strategic interaction between the government and speculators in the foreign exchange market, with the government deciding whether to defend or abandon the currency peg based on the proportion of speculators attacking. The analysis shows that the government's decision is influenced by the cost of defending the peg and the proportion of speculators attacking. The paper also discusses the implications of changes in transaction costs, aggregate wealth, and the information structure on the incidence of currency attacks. The results suggest that policies aimed at restoring transparency and common knowledge of fundamentals can help prevent currency crises.