中国上市公司股权激励的短期和长期效应研究

发布时间：2018-08-20 08:21

【摘要】：现代公司的发展使得公司的所有权和经营权出现了分离。股权激励计划是解决由此带来的委托代理问题最有效、最重要的手段之一。本文选取了2006年至今的宣布股权激励计划的全部公司样本。首先,我们运用全部样本,研究股权激励计划宣布的短期股价效应。这一部分主要采用的是事件研究法。然后我们使用实施了股权激励计划的那些公司作为样本,研究股权激励计划在长期是否能提升公司业绩。如果认同市场有效(只要弱有效),股价长期来看能够反映公司的业绩,那么长期来看,实施股权激励计划的公司的股票是不是有超额正收益。我们用编制股权激励组合的指数的方法来看股权激励在长期是否能够激励公司的股价,给股东或者投资者带来超额收益。研究发现我国在市场上,当宣布股权激励计划的时候,该公司的股票是有超额正收益的,并且这种超额正收益在统计上是显著的。我们还发现不同类别的公司的超额收益是有差别的,我们对这些差异的成因做了一定的研究和讨论。在长期的效应中,业绩效应方面,我们发现实施股权激励计划后,公司业绩往往有一个略微下调的过程,我们认为可能是上市公司盈余管理,通过“藏业绩”或者“平滑业绩”以使自己在将来市场环境不好的时候也能达到行权的业绩条件。经过这个短暂的下调之后,长期来看,股权激励计划可能是会提高公司的业绩的。由于数据不够多,我们的研究只是弱支持这个结论。在股价效应方面,我们编制的股权激励指数能够远远的跑赢大盘,股权激励能够激励公司股价是肯定的。不过,由于一种逆向选择现象的存在,即在中国是一般都是好公司才实施股权激励计划,而即便股权激励在长期来看不能带来业绩的明显提升的话,他们业绩仍然是很好的,从而他们的股票有远超大盘的收益率。因此,即便股价提升,也不一定就是股权激励的实施造成的公司业绩提升造成的。综合来看的话,我们认为股权激励长期来看能够激励公司的业绩和股价。
[Abstract]:The development of modern companies makes the separation of ownership and management rights. Equity incentive plan is one of the most effective and important means to solve the principal-agent problem. This paper selects all the company samples of the announced equity incentive plan from 2006 to present. First of all, we use all samples to study the short-term stock price effect of equity incentive plan announcement. This part mainly adopts the event research method. Then we use the companies that have implemented the equity incentive plan as a sample to study whether the equity incentive plan can improve the company's performance in the long run. If you agree that markets are efficient (as long as they are weak) and share prices reflect the company's performance in the long run, then in the long run, whether or not the stock of the company implementing the equity incentive plan has an excess positive return. We use the method of compiling the index of equity incentive portfolio to see whether equity incentive can stimulate the stock price of the company in the long run and bring excess return to shareholders or investors. It is found that in our country, when the equity incentive plan is announced, the stock of the company has excess positive returns, and this excess positive return is statistically significant. We also find that there are differences in the excess returns of different types of companies, and we have done some research and discussion on the causes of these differences. In the long-term effect, the performance effect, we found that after the implementation of equity incentive plan, the performance of the company often has a slightly downward process, we think it may be listed company earnings management, Through the "hide performance" or "smooth performance" so that in the future when the market environment is not good, can also achieve the performance conditions of the exercise of power. After this brief downgrade, in the long run, equity incentives may improve the company's performance. Due to insufficient data, our study only weakly supports this conclusion. In terms of stock price effect, the stock incentive index we compiled can far outperform the market, and the equity incentive can stimulate the stock price of the company for sure. However, because of the existence of adverse selection, which is generally good companies in China to implement equity incentive plan, and even if equity incentive can not bring about a significant improvement in performance in the long run, their performance is still very good. As a result, their stocks yield far more than the market. Therefore, even if the stock price rise, it is not necessarily caused by the implementation of equity incentives to improve corporate performance. On the whole, we believe that equity incentive can stimulate the company's performance and stock price in the long run.
【学位授予单位】：南京大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：F832.51;F276.6

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