本研究主要探討台灣上市(櫃)公司股權結構，董事會監督機制是否會 降低權益資金成本？本文將代理問題區分為核心代理問題和權益代理問 題，探討公司治理對權益資金成本之影響。實證結果表示：（1)管理者持 股與權益資金成本呈負相關。（2)控制權與現金流量請求權偏離程度愈 大，權益資金成本愈大，顯示核心代理問題會使投資人要求較高之風險 溢酬。（3)(4)權益資金成本會隨董監持股比率、外部董監事比率及機構投 資人持股比率而減少，但會因董監事股權質押及董事長兼任總經理而增 加。（5)核心代理問題和權益代理問題具有抵換關係。

The purpose of this paper is to examine the effect of ownership structure and board characteristics on cost of equity capital. The main feature of this study is that we divide the agency problem into core agency problem and equity agency problem, and we explore the relation between corporate governance and cost of equity capital. Overall, this paper expects to explain corporate governance and can reduce agency problem and the efficient corporate governance can decrease cost of equity capital. The empirical results indicate as follows: First, managerial ownership is negatively related to cost of equity capital and hence supports convergence-of-interest hypothesis. Second, as controlling right deviates from cash flow right, cost of equity capital is getting worse, that is, core agency problems become more serious in the firm. Third, the shares of board directors, institutional ownership and the number of the outside directors have negative relationship with cost of equity capital, but the pledged share ratio of directors and the chief executive officer (CEO) duality have positive relationship with cost of equity capital. Finally, Trade-off Relationship between core agency problem and equity agency problem.