中國公司治理與績效的關係—探討股權分置的後續影響

Abstract

本文選定上海 A 股上市公司作為研究對象,探討在股權分置改革事件後,新 舊上市公司的企業治理對於績效的差異。以 Tobin's Q 作用公司績效的衡量指標, 控制公司年齡,負債比例,淨值報酬率和長期負債比例四個變量,研究前十大股 東持股比例,國有股持股比例和境內外機構投資人持股比例對公司績效的影響, 並用虛擬變量加以區分股改前後和新舊上市公司兩個變數,以了解在股權分置事 件之後,新舊公司之間是否存在績效差異。 本文採用固定效果最小二乘法虛擬變量(fixed effects least squares dummy variable, LSDV)和隨機效應模型(random effects model, REM)分析樣本數據, 結果顯示,國有股持股比例,境內外機構投資人持股比例的減持在股權分置改革 後對於公司績效有顯著提升,前十大股東持股比例在股權前後無顯著變化;這四 個變量在新舊上市公司間無顯著差異,說明股權分置改革達到了目的。

This study is based on the companies (A shares)listed in the Shanghai Stock Exchange, to explore the impact of the old and new corporate governance on performance with the long-term effects of the reform of split share structure in China. This analysis uses Tobin's Q to measure the corporate performance, and studies the corporate governance effects from the sum of the shareholding of ten largest shareholders, the proportion of state-owned shares, the proportion of shares held by the domestic and foreign institutional ownership, under the controlling four variables of company age, debt ratio, return on equity and long-term debt ratio. Meanwhile, using the dummy variable to distinguish the companies between old and new, and the time before and after the share structure. Under those hypothesis, this study tried to find the differences performance between the old and new companies. In this paper, the fixed effects least squares dummy variable and random effects models are used to analyze the panel data sample. The results show that the reduction of the stake from the proportion of state-owned shares held, domestic and foreign institutional investors have significantly improved performance for the companies. But the sum of the shareholding of ten largest shareholders showed no significant change. At the same time, this paper finds no evidence of significant difference between the old and new companies on performance.