在固定匯率制度下，政府的政策目標，為維持匯率的穩定、物價的穩定或利率的穩定等。在外匯市場中有許多參與者，包含了匯率的投機者，他們預期匯率的升值或貶值，並予以投資或投機性的攻擊。因此，我們探討國際間的投機者如何形成一個重覆合作賽局並選擇策略，並引入央行的成本函數和針對央行如何在外匯市場中進行操作、政府如何維持政府目標、以及如何避免遭受匯率攻擊進行討論，以進一步分析經濟體系最後所形成的長期均衡狀態。 本文沿用Kandori, Mailath and Rob(1993)之演化性賽局模型為基本架構，考量投機者之預期心理因素，並討論央行的成本函數以建構出其目標方程式，及分析央行所採取的策略，此外，透過國際間投機者所形成的貨幣賽局，探討投機者採取的策略與預期報酬之間的關聯性。 本研究顯示出三個主要結果： (1)央行持有之名譽成本多寡將會影響到固定匯率制度崩潰的時間點。(2)投機者在預期報酬高於其交易成本時，投機者才會進行貨幣攻擊。(3)當國際間投機者組成合作賽局並聯合攻擊一經濟體系後，經濟體系所形成的均衡為單一均衡，亦即攻擊均衡狀態。 The purpose of this study is to explore how the foreign currency speculator chooses the optimal strategy in the currency game and how the government policy effect the exchange rate regimes. This paper develops an evolutionary model from Kandori, Mailath and Rob(1993) (henceforth KMR).The forex market is consists of heterogeneous speculator, each of whom are learning through imitation and experimentation in the coordination game. Our model involves the central bank’s loss function, International Fisher Effect and the speculator self-fulfilling expectation in currency attacks. We construct the central bank’s loss function to analyze the central bank optimal strategy in abandon the fix exchange rate regime. The results of this study reveal as follows: (1) The optimal strategy for the central bank is to abandon the fix peg if and only if the foreign exchange reserves is inadequate. (2) In any period t, the optimal strategy for a speculator is to attack the currency if and only if the expected payoff is higher than the transaction costs. (3)The result of evolutionary dynamic will converges to a unique long run equilibrium, which is the “attack” equilibrium.
