公司增加獨立董事席次及設置審計委員會與盈餘品質之研究──法規擴大強制範圍之影響

A Study on the Association between Increasing Independent Directors and Establishing Audit Committee, and Earnings Quality: The Impact of an Expanded Scope of Regulations

近年來我國主管機關大力推動獨立董事與審計委員會制度，以降低代理問題並確保公司財務報表品質。本研究探討增加獨立董事席次或設置審計委員會此兩項盈餘品質指標，於主管機關擴大強制設置獨立董事與審計委員會之範圍後，是否將使投資人對公司財務報表增額信賴程度減少，而使公司之增額盈餘反應係數降低。本研究以台灣上市櫃公司2011年至2017年間之資料，採差異中之差異法（Difference-in-Difference Method）進行實證測試。實證結果顯示，於法規擴大強制範圍前，公司增加獨立董事席次與設置審計委員會確能提高投資人對公司財務報表之信賴程度而產生增額盈餘反應係數；惟於法規擴大強制範圍後此增額盈餘反應係數顯著降低，顯示增加獨立董事席次或設置審計委員會作為盈餘品質指標之訊號（signal）效果，確於法規擴大強制設置獨立董事與審計委員會之範圍後有所下降。 Taiwanese authorities recently expanded the scope of regulations pertaining to boards of directors with the aim of mitigating the agency issue and ensuring the quality of financial reports. Based on the fact that increasing the number of independent directors and forming an audit committee are viewed as indictors of earning quality, this study examined whether the expanded scope of regulations reduces the incremental reliance on financial statements, as manifest in a decrease in the incremental earnings response coefficient. We applied the difference-in-difference method in our analysis for companies listed in Taiwan between 2011 and 2017. The empirical results show that prior to the expanded scope of regulations, an increase in the number of independent directors and the formation of audit committee tended to increase investors' reliance on financial statements, as reflected in an incremental earnings response coefficient. Following the expanded scope of regulations, there was a significantly decrease in incremental earnings response coefficient, which suggests that the signal effect of the two indicators of earnings quality was less pronounced under the expanded scope of regulations.