訊息引發的貨幣危機

Currency Crisis Triggered by News

貨幣危機的全域賽局模型強調訊息事件可以引發貨幣危機，一般認為投機者攻擊可以實現總體經濟結構不變之下，卻能夠導致貨幣危機。而且為了防止貨幣危機，政府必須防禦投機者的攻擊。然而，防止投機者的貨幣攻擊與政府的整體目標並不相符。本文利用傳統的總體架構在貨幣危機的全域賽局模型中為政府尋找合理的目標，且沒有額外考慮投機者的攻擊性行為。利用合理的政府目標可以推導出政府應該採取透明政策的基本範圍，且可證明當透明化政策的成本足夠小時，政府才會採取透明化政策來預防貨幣危機。最後，本文進一步探討了超主權貨幣防止貨幣危機的可行性。雖然超主權國際貨幣可以防止貨幣危機，但是政府失去貨幣自主權相關的經濟風險可能會使政府面臨更高的成本。即使原本的固定匯率嚴重高估本國貨幣，也只有在很小的基本面範圍內，政府才可能使用超主權貨幣來防止訊息事件所引發的貨幣危機。

The global game model of currency crises emphasizes that information events can trigger currency crises. Speculator attacks are often thought to leave unchanged macroeconomic structures but lead to currency crises. To prevent currency crises, governments must thus defend themselves against attacks by speculators. But guarding against currency attacks by speculators is inconsistent with the government’s overall goals. This paper uses a traditional macroeconomic framework to find reasonable goals for the government in the global game model of currency crises without additional consideration of the aggressive behavior of speculators. We use reasonable government goals to derive the fundamental range within which governments should adopt transparent policies, and show that when the costs of transparent policies are small enough, governments can adopt transparent policies to prevent currency crises. Finally, this paper further explores the feasibility of a super-sovereign international currency to prevent currency crises. While a supra-sovereign international currency can prevent currency crises, the economic risks associated with governments losing monetary autonomy may expose governments to higher costs. Even if the fixed exchange rate seriously overvalues the domestic currency, it is only within a small range of fundamentals that the government may use a supra-sovereign international currency to prevent currency crises caused by information events.