杠杆率在公司并购后的变动——部分调整模型的应用

Leverage Changes after Takeovers： An Application of Partial Adjustment Model

本文考察了主并公司的杠杆率在并购之后长期内的变化情况，并通过并购这一事件来验证权衡理论及其他替代性资本结构理论。首先，本文通过标准部分调整模型来检验并购之后主并公司的实际杠杆率向最优值回复的速度，发现调整速度低但相对稳定，因而初步支持权衡理论。然而，这种低调整速度可能是由高调整成本引起，也可能是由权衡理论的替代理论的效应引起。为进一步区分原因，本文通过在部分调整模型中加入额外的变量来检验权衡理论的替代理论的效应。进一步的检验结果再次支持了权衡理论，从而间接表明低调整速度是由高的调整成本引起的。

This research investigates the changes of acquiring firms＇ leverage ratios after takeovers in order to test the trade-off theory and its alternative capital structure theories. At first, this research utilizes the standard partial adjustment model to examine the speed of adjustment of acquiring firms＇ leverage ratios moving towards the optimal leverage ratios in the post-acquisition period. It discovers low but persistent adjustment speed, therefore supports the trade-off theory, i.e. , firms attach themselves to optimal leverage ratios and actively diminish the deviations from optimal levels. However, the low adjustment speed could be caused by either the adjustment costs or by the influence of alternative capital structure theories. In order to distinguish these two factors, this research then makes use of modified partial adjustment models to test the influences of competing theories. The additional tests do not support any of the alternative theories, thus support the trade-off theory, and give indirect evidence that the low adjustment speed is caused by adjustment costs.