董事网络、信息不对称和并购财富效应

Board Networks,Information Asymmetry and Wealth Effects of M&A of Listed Companies

本文从董事网络能够减少公司并购时信息不对称的角度出发，研究了董事网络对并购参与双方财富效应的影响。与现有的文献不同，在对2007～2011年间共2401起并购事件的研究中，本文发现收购公司向董事网络中心位置靠近的过程中，公司的并购财富先增加，在达到一个最优点后，开始下降，呈现倒u型关系。而单纯改变目标公司在董事网络中的位置，并不能明显提高其财富效应，只有通过董事网络获取高质量的信息才能对其财富产生明显作用。深入验证董事网络对降低信息不对称的作用的实证结果表明，在信息披露质量差的公司中，董事网络发挥的作用更显著。

In this paper, we consider that better network boards have access to important information via their networks that makes them more informed in their monitoring and decision-making capacities. M＆A behavior, as an economic act, faces lots of risks. M＆A information is usually divided into public information and private information which refers to the undisclosed information in the potential counterparties. Board networks are efficient ways to de- liver private information, which can break the limitation of mastering two sides＇ information and thus weaken the in- formation asymmetry risk. Whether board networks can influence M＆A wealth and how to influence has attracted wide attention of scholars at home and abroad, but they have not get consistent results due to different samples and indicators selected. Based on the view that board networks can reduce information asymmetry, this paper studies the influence of board networks on the wealth of acquiring and target firms. Firstly, in the process of selecting the transaction object, the existing of board networks is helpful to pass true and useful information between the potential acquirers and tar- gets; meanwhile, these companies might have information advantages thus they can grasp the M＆A opportunities more easily. Secondly, on one hand, after selecting transaction object, acquiring firms can estimate the value of tar- gets accurately in order to avoid overpayment. On the other hand, in the implementation of acquisition process, the director networks can transfer information within the two sides to make strategy timely to increase both sides＇ wealth effect. Thirdly, after an agreement in the transaction, acquiring firms can understand the advantages of each other in order to fully integrate their resources, which also increase the wealth effect of both sides. In addition, more informa- tion means higher market position which could also reduce transaction costs. Different from the existing literatures ,we use 2401 M＆A events happened during 2007 to 2011. Centrality in- dexes（ degree, betweenness, closeness, eigenvector） have been used to measure board networks and three-day cumu- lative abnormal returns to measure the wealth effects of M＆A events. For the measurement of information asymme- try,we follow the rating standard of information disclosure of Shenzhen Stock Exchange to classify the Shenzhen Stock Exchange listed companies of our sample into four classes--excellent, fine, qualified and below standard. Particularly, the first two classes are combined into one subsample which face less information asymmetry, and the after two classes are combined into another subsample, which face stronger information asymmetry and rely more on their board networks. At the same time, given the outliers in our sample, we choose median regression for our test. The conclusion is that in the process of acquiring firms approaching increases at first but then decreases after reaching an optimal point; the the center of the board networks, its wealth marginal value of the information obtained through board networks decreases with too busy boards, that is, the relationship between acquiring firms and their wealth presents an inverted U-shaped relationship. However, just changing the target firms＇ position in the net- works, their wealth does not increased remarkably; only high-quality information can play a positive role in their wealth. In the further examination of the board networks＇ impact on the reduction of the information asymmetry, we find that the lower quality of information disclosure is, the more significant effects of the board networks are ; never- theless, in the target firms with poor quality of information disclosure, information via board networks does harm to their wealth. In addition, to examine whether board networks lead to information leak before M＆A events, we intro- duce variable of information leak rate for robustness test and find that our results have not been affected by information leak.