本研究以代理理論為基礎，探討董事會的獨立性與忙碌程度，對公司獲利 能力與市場價值的影響。本研究把外部董事區分為灰色董事與獨立董事，並主 張二者的屬性與職能不盡相同，故對公司績效也應有不同影響。本研究採用 2018 至2020 年台灣1,314 家上市櫃公司之三年期資料進行實證分析，結果發 現，在董事會獨立性方面，灰色董事比例對ROA 與Tobin’s Q 皆有負向影響， 而獨立董事比例則對Tobin’s Q 呈現先下降後上升的U 型曲線關係。在忙碌程 度方面，忙碌灰色董事對ROA 與Tobin’s Q 皆呈現先下降後上升的U 型曲線 關係，但忙碌獨立董事則有負向影響。本研究將灰色董事與獨立董事的職能角 色加以區分，並實證分析其對公司績效的不同影響，可望對當代公司治理的理 論與實務做出貢獻。

This study is based on agency theory to examine the relationship between board independence, board busyness, and firm performance. This study sorts outside directors into grey and independent directors, and argues that these two types of directors have different impacts on firm performance due to their different attributes and functions in corporate governance. The research sample contains 1,314 public Taiwanese firms during the period from 2018 to 2020, with nonlinear regression analyses as main statistical tools. The empirical results show that the percentage of gray directors is negatively associated with the ROA and Tobin’s Q of firms, while the percentage of independent directors shows a U-shaped relationship with Tobin’s Q. Regarding board busyness, busy gray directors show a U-shaped relationship with ROA and Tobin’s Q, while busy independent directors show a negatively impact. Our study views gray and independent directors as two different types of directors, and empirically examines how their different roles lead to different implications on firm performance. Findings of this study are expected to contribute to the academic literature and management practice of corporate governance.

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