封閉型基金長期折價的現象由來已久。一般咸認為其績效必定較開放型基金為差，而政府政策似乎有意將封閉型基金轉型為開放型基金。封閉型基金的績效真的較差嗎？過去有關基金績效的評估研究，多半利用以CAPM為基礎的指標來衡量績效，但是這些指標都有實證上的缺陷，造成其準確性與適用性受到質疑。本研究以APT為基礎，發展出一個基金評估的新指標，結果發現，封閉型基金在評估各期中，其多數的績效排名，皆優於開放型基金，而且此一新指標與CAPM傳統指標間雖排名差異不大，但在基金排名競爭激烈的環境中，慎選績效評估指標是非常重要的。本研究對投資人、政策制訂者及學界，均提供一些涵義。

It has long been known that the phenomenon of price discount is prevailing for closed-end funds. Averaged investors seem to think that the performance of closed-end funds is inferior to that of open-end funds and the SEC policy seems to direct the closed-end funds to transform to open-end funds. Are performance of closed-end funds really worsen than that of open-end fund? Most of past empirical studies on performance evaluation are based on the CAPM. However, the validity and accuracy of those CAPM-based performance-evaluation Indexes are seriously criticized. This paper, based on the arbitrage pricing model, develops a new performance-evaluation index. We find that, in the whole period and most of subperiods, most of closed-end funds performed better than open-end funds. Although the difference in ranking between the new index and those CAPM-based indexes are small, it is important to choose a right index in the competitive environment. This study provides many implications to investors, policy markers, and academic workers.