本文以報載之央行外匯干預新聞作為央行實際干預發生之代理變數，研究央行干預與台幣對美元匯率之間的關係，以及央行外匯干預的效果。由於台灣央行從未公開其外匯干預之實際行為，過去文獻多以央行外匯存底之變化作為央行干預之代理變數。而本篇研究以每日央行干預新聞作為央行實際干預的代理變數，使我們得以從日資料分析央行的干預行為與效果。

本文的研究結果顯示，央行的主要干預方式屬於文獻所謂之「逆勢而行」(leaning against the wind)，亦即央行會在台幣升勢加大時進場阻升，台幣貶勢加大時進場阻貶。並且央行在干預時很少試圖強力扭轉當日的市場走勢，而是以類似踩煞車的方式阻止匯率升貶幅的進一步擴大。此外本文也證實文獻中關於央行「阻升不阻貶」之不對稱現象。
最後本文以事件研究方法探討央行干預的有效性，發現台灣央行的外匯市場干預對匯率走勢多有達成與央行干預方向一致之結果。

This paper uses news report on the foreign exchange intervention conducted by the Taiwanese central bank (CBC) to analyze how such actions affect the NTD/Dollar exchange rate. We adopt the event study method proposed in Fatum and Hutchison (2006), using the news reports to define intervention events. Then we compare the average rate of return of NTD/Dollar exchange rate two days and five days before and after every intervention event, to check the effect of central bank intervention. We conclude that the CBC’s interventions are usually successful in achieving the central bank’s objectives.

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