董事年資、獨董兼任與公司績效之關聯性──以台灣通訊網路產業為例

Relationship between Directors’Tenure, Multiple Directorships of Independent Directors, and Firm Performance - Evidence from Taiwanese Communication Network Industry

隨著在2020年網路技術規範完成版本公布以及相關應用陸續成熟後，投資人預期通訊網路產業將有進一步的發展。本研究以台灣通訊網路產業為研究對象，探討董事年資與獨董兼任對企業績效的影響。樣本包括147家上市櫃通訊網路廠商，研究期間為2010年至2018年。本研究使用縱橫資料模型進行分析，實證結果顯示，董事年資負向顯著地影響企業績效；董事年資增加，可能損害董事會獨立性或不利於創新與成長機會，導致企業績效降低。獨董兼任有顯著的倒U型效果；獨董兼任帶來重要的外部資源，可以提升企業績效，但是兼任席次超過某一門檻，反而使績效減少。除上游廠商的董事年資對Tobin’Q有U效果外，以上下游次樣本與二階段最小平方法進行穩健性測試，仍然支持主要結果。整體而言，通訊網路廠商應該雇用可帶來創新與成長機會的新董事以及不太忙碌的獨立董事。

With the release of the completed version of the network technical specifications in 2020 and the gradual maturity of related applications, investors expect that the communication network industry will have further development. The purpose of this study is to investigate whether directors’tenure and independent directors with multiple directorships influence firm performance in Taiwanese communication network industry. This study uses 147 listed firms for the period from 2010 to 2018 and employs the panel data model to conduct the analysis. The results show that directors’tenure has a significant and negative impact on firm performance. Long tenure may decrease board independence or impair innovation and growth opportunities, resulting in low firm performance. Independent directors with multiple directorships have an inverted U-shaped effect on firm performance, indicating that multiple directorships are effective at improving firm performance by providing vital outside resource but ineffective over a certain threshold value. This study also tests for robustness using up- and down-stream subsamples and two-stage least square method. The main results are robust in comparison to these alternative specifications, except for the U-shaped effect of directors’tenure on Tobin’s Q in up-stream manufacturers. Overall, firms can benefit from recruiting new directors who can bring firms with innovation and growth opportunities and independent directors who are not too busy.