在不完全市場下，衍生性金融商品可利用上套利和下套利價格來訂出價格區間。我們運用效用無差異定價於此篇論文中，此定價方式為尋找一個初始交易價，會使在起始時交易商品和無交易商品於商品到期日之最大期望效用相等。利用主要的對偶結果，我們證明在指數效用函數下，效用無差異定價區間會比上套利和下套利定價區間小。 / In incomplete markets, prices of a contingent claim can be obtained between the upper and lower hedging prices. In this thesis, we will use utility indifference pricing to nd an initial payment for which the maximal expected utility of trading the claim is indierent to the maximal expected utility of no trading. From the central duality result, we show that the gap between the seller's and the buyer's utility indierence prices is always smaller than the gap between the upper and lower hedging prices under the exponential utility function.