經理人持股、內線交易、監督與公司價值

MANAGERIAL OWNERSHIP INSIDER TRADING MONITORING AND THE VALUE OF THE FIRM

本文在Burkart et al.(1997)的架構下，探討經理人持股與經理人從事內線交易，對大股東的監督水準、經理人的努力水準、最適股權結構（大股東持股）與公司價值的影響。我們證明當經理人持有公司股票，與經理人從事內線交易時，存在一個唯一的最適股權結構。隨著經理人持有的公司股票增加，經理人決策被大股東否決的機會成本下降，最適大股東持股將會增加，最終使得大股東的監督水準、經理人的努力水準，以及公司價值增加。此外，研究發現經理人在股票市場從事內線交易，雖會剝奪外部股東的利益、產生經理人在計畫風險選擇的扭曲，但卻可降低經理人與大股東之間的利益衝突，並使經理人的努力水準增加，當經理人內線交易所能獲得的超額報酬，以及投資計畫帶給他的私人利益相對低時，經理人從事內線交易是有可能對公司價值產生正面效果的。

We extend the Burkart et al. (1997) model by allowing for managerial ownership and insider trading. It is shown that optimal ownership structure is increasing in the managerial ownership due to a decrease in the manager’s opportunity cost when being overruled by large shareholders. Consequently, a larger managerial ownership increases the monitoring by large shareholders, the manager’s effort, and the value of the firm. We also argue that insider trading comes with costs but also with benefits. On the one hand, if allowing to insider trading, a manager inclined to undertake those projects with higher risk. Furthermore, insider trading will hurt outside shareholders and finally reduce the firm’s value. On the other hand, allowing the manager to trade in the stock market can induce his managerial effort and reconcile the conflict of interests between manager and large shareholders. It is revealed that positive effects overweight negative effects towards the firm’s value when the manager’s private benefit is relatively small.