董事會特性、股權結構與公司績效關係之研究

Abstract

本研究以2011年(含)以前在台灣證券交易所上市，且於2013年底仍上市之公司為研究樣本，共706家公司作為本研究之研究對象。本研究旨在探討董事會特性，以及股權結構兩個內部公司治理機制，對於公司績效之影響，並同時以財務績效ROA以及公司價值Tobin’s Q兩項指標，衡量公司績效。本研究選擇了董事年資、股權集中度，以及外部股東持股比例等三個指標，作為研究變數，同時納入公司年齡、公司規模、公司負債比例、產業別、法人股東持股比例、金融機構持股比例、是否為公股主導等七個變數作為控制變數，進行多元線性迴歸分析。本研究之結論如下： 1. 董事年資與財務績效之間存在先升後降的倒U曲線關係，而與公司價值之間，不存在顯著的倒U曲線關係。此結論說明，隨著董事年資增加，對於公司與產業之熟稔度上升，有助董事會協助經理人做出正確決策，達到興利的效果；然而當董事年資達到一定程度時，董事彼此過於熟悉，恐降低團隊思考的效果，並喪失董事珍貴的獨立性，不利監督職能，因此對除弊的目的有害，抵消了董事年資增加所帶來的知識益處。在此結論下，董事會應適時調整成員組成，避免平均年資過長，以提升公司績效。 2. 股權集中度與財務績效之間無顯著關係，然而股權集中度與公司價值之間存在顯著的正向關係。此結果支持了利益收斂假說以及信號傳遞假說，由於台灣家族企業比例高，股權集中度高的公司，多為集團或家族控制，並會派遣家族成員至公司內部擔任經理人，此條件與利益收斂假說，以及信號傳遞假說之情形相符合。然而實證結果僅發現，股權集中度與公司價值呈現正向關係，說明資本市場較青睞股權集中度高的公司，即使其並未能夠顯著在財務績效上，優於股權集中度低的公司。 3. 外部股東持股比例，會正向影響財務績效，然而與公司價值之間沒有顯著關係。研究結果說明，外部股東可以作為監督大股東的存在，降低大股東與小股東之間的代理成本，提升公司治理的效果，進而提高公司的財務績效。因此，公司在股權結構的設計上，應引入外部股東，避免大部分股權被控制集團或友好集團掌握，以提升公司財務績效。然而，資本市場並無顯著偏好外部股東持股比例高之公司。

This study provides an evidence of relationship between firm performance and board characteristics, as well as firm performance and ownership structure in Taiwan. The sample includes 706 firms that had been listed in Taiwan Securities Exchange before end of 2011. This study tries to explain how the two internal corporate governance mechanism, board of directors and ownership structure, affect firm performance. At the same time, this study uses dual indicators, financial performance indicator ROA and firm value indicator Tobin’s Q, to evaluate the effect of board characteristics and ownership structure. This study focuses on the effect of board tenure, ownership concentration and outside shareholder shareholdings. Control variables in this study include firm age, firm size, firm’s debt ratio, industry, shareholdings of institute, shareholdings of financial institute, and whether the firm is controlled by government. The study applies multiple linear regressions as the quantitative analysis method. The followings are the conclusion from the result of the analysis: 1) Board tenure has a U-shape relationship with firm’s financial performance, but the relationship does not exist between board tenure and firm value. This indicates that on one hand, with the increase of board tenure, the more the boards are familiar with the firm and the industry, which helps the boards to assist managers to make right decision. While on the on the hand, due to the over-familiarity within board members, the groupthink may come out, and the independence of board members are eliminated as a result, even to the extent that it overpass the benefit brought from accumulated knowledge with increasing tenure. With this finding, board of directors should adjust its composition adequately over time to avoid too-long board tenure. 2) The ownership concentration has no significant relationship with the firm’s financial performance, while it positively affects the firm value. This implies that capital market prefers companies with concentrated ownership structure even they don’t significantly outperform the companies with lower concentration of ownership. 3) The ratio of outside shareholder shareholdings influences the firm’s financial performance in a positive manner, while there’s no significant relationship between outside shareholder shareholdings and the firm value. The finding indicates that outside shareholders can supervise the major shareholders, and reduce the agency cost between major shareholders and minor shareholders, and as a result improve the quality of corporate governance. Thus, companies should introduce outside shareholders when designing the ownership structure.