This paper links two applications of Extreme Value Theory (EVT) to analyze Taiwanese financial markets: 1. computation of Value at Risk (VaR) and Expected Shortfall (ES) 2. estimates of cross-market dependence under extreme events. Daily data from the Taiwan Stock Exchange Capitalization Weight Stock Index (TAIEX) and the foreign exchange rate, USD/NTD, are employed to analyze the behavior of each return and the dependence structure between the foreign exchange market and the equity market. In the univariate case, when computing risk measures, EVT provides us a more accurate way to estimate VaR. In bivariate case, when measuring extremal dependence, the results of whole period data show the extremal dependence between two markets is asymptotically independent, and the analyses of subperiods illustrate that the relation is slightly dependent in specific periods. Therefore, there is no significant evidence that extreme events appeared in one market (the equity market or the foreign exchange market) will affect another in Taiwan.

本文以資料包絡分析法衡量2004年第一季至2008年第三季台灣商業銀行之效率與生產力，並以其代表銀行之經營績效。不同於過去文獻之處在於本文以前瞻之觀點（沈中華，2005）求出放款預期損失以衡量放款風險，作為放款過程中的非意欲產出。本文並利用Ray and Desli（1997）架構拆解Malmquist總要素生產力指數，探討銀行績效變動之來源，此外，亦將該拆解結果與Färe et al.（1994）拆解方式比較，發現在技術變動部分有明顯不同。本文並探討影響銀行效率之因素以及檢定不同類型銀行之生產力表現是否有顯著差異。 / The purpose of this paper is to examine the efficiency and productivity change of Taiwan’s banks over 2004Q1-2008Q3 using data envelopment analysis. Unlike the literature of the past, this paper uses the forward-looking viewpoint to derive expected losses from loans to measure the credit risk. In addition, the loan expected loss is thought of as an undesirable output in the estimation of efficiency and productivity. On the other hand, this paper uses a VRS frontier benchmark (Ray and Desli, 1997) to analyze the sources of productivity change. This paper also compares this result with that of Färe et al.（1994）decomposition, and finds that the estimated technical changes of two approaches are significantly different. Further, this paper analyzes the factors influencing banks’ efficiency, and investigates the productivity differences between different ownerships.