中文摘要：

基于实施保荐制度后IPO上市的样本，本文首次实证研究了保荐制度背景下A股IPO的过度包装与定价效率问题。结果发现：保荐制度未能有效减少新股上市过程中的过度包装现象；过度包装是造成A股IPO定价低效率的主要原因；保荐人声誉无助于IPO定价效率的提高；相比较而言，创业板的定价效率最低。可见，中国证监会推出保荐制度的初衷未能如愿。因此，构建上市约束机制，加大对违规上市的惩戒；改革保荐制度，加大保荐机构和保荐人违规惩罚力度；完善公司内部治理，尤为必要。

英文摘要：

This paper is the first one to study the problem about over-packaging and pricing efficiency of A-shares by the means of empirical research. It can be found from the results： sponsorship system doesn＇t decrease the over-packaging phenomenon in the process of initial public offering： over-packaging is the primary cause of the low pricing efficiency of A-shares; the reputation of sponsor make no contribution to improve the IPO pricing efficiency; by comparison, the pricing efficiency of Growth Enterprises market is the lowest. So, the original intention of implementing the sponsorship system doesn＇t be realized. It is necessary to build listing constraint mechanism, increase the punishment for listing discipline violation, reform sponsorship system, increase the punishment for sponsor institutes and individuals, and perfect the company internal governance.