本文旨在以La Porta et al. (1999)最終控制股東衡量法，探討我國上市公司控制股東代理問題對公司價值之影響，並開創國內先例，分析對外舉債是否能發揮監督功能。實證結果發現: 控制股東存在與否，不影響公司價值; 控制股東以金字塔結構或交叉持股方式增加控制權之比率不高，故控制權與現金流量請求權間之偏離程度大小，並不影響公司價值，唯若控制股東參與管理時，將降低公司價值; 在ROA 衡量基準下，以家族與政府部門類型為最終控制股東者，均能增加公司價值。此外，亦發現代理問題存在時，公司對外舉債確能增加公司價值，其中又以發行擔保公司債之資金募集方式，最能發揮監督功能。

Using data of Taiwan stock market, this article investigates the influences of controlling shareholders’ agency problem on corporate performance by using ultimate controlling shareholders approach. The hypothesis that debt would reduce agency costs is also examined. The empirical results show that controlling shareholders do not expropriate corporate values. Evidences do not support the proposition that some controlling shareholders would influence corporate performance by utilizing pyramid ownership structures and cross-holding to separate voting and cash flow rights. However, the corporate value would decrease if controlling shareholders involved in management. Our results also reveal that debt mitigate the loss from those misaligned incentives.