董事會與信用風險承擔：以臺灣商業銀行為例

Board of Directors and Credit Risk-Taking: Evidence from Taiwanese Commercial Banks

本研究以2006至2018年間的臺灣商業銀行為樣本，並以放款公司的信用評等做為銀行的信用風險承擔指標，發現當董事會結構能強化其監督功能時銀行承擔的信用風險越低。獨立董事、財務專業董事、兼任經理人董事及女性董事比例越高，放款公司平均信用評等越好，董事股權質押比率則與其呈正相關；董事會規模、風險管理委員會的設置則與之並無明確關係。而各項董事會結構因子皆與逾期放款比率無顯著關係，顯示以事前指標評估風險承擔意願的重要。本研究並以工具變量方法確立上述關係的因果推論。另外，較嚴峻的資訊環境或是金融危機的發生，並不影響獨立董事及財務專業董事的監督效果，卻大幅削弱女性董事的影響。由研究結果可知，董事會的獨立性，專業背景及質押比率為影響銀行承擔信用風險的主要因子，故政策制定者可透過規範董事會結構及行為調整銀行承擔的風險。

Using a sample of Taiwanese commercial banks between 2006 and 2018, this study finds evidence of a link between risk-taking behavior and multiple board characteristics that enhance board monitoring. . Risk-taking behavior is measured in terms of the average credit rating of the borrowing firms. The level of risk-taking decreases as the proportion of independent directors, financial expertise directors, insider directors, and female directors increases. Risk-taking increases in the percentage of shares pledged by directors. Board size and the presence of a risk management committee have no significant effect on risk-taking policies. We find no significant relationship between board structure and the percentage of non-performing loans, highlighting the importance of assessing credit risk-taking via an ex-ante measure. The causal inference is established using an instrumental variable approach. In addition, in more complex informational environments or during a financial crisis, the monitoring effect of independent directors and financial directors is sustained, while the influence of female directors weakens significantly. The results indicate that board independence, expertise, and directors’ pledging of shares are the main factors that contribute to the effective monitoring of credit risk, and suggest that policy makers may effectively target bank risk-taking policy through regulating board structure.