中文摘要：

构建需求理论模型分析询价对象范围、网下配售比例及锁定期变化对IPO抑价的影响,并采用国际IPO数据针对理论结果进行实证检验。理论分析表明,随询价对象范围的增加并超出某一临界值后,抑价率呈现先下降后上升的趋势,而之前并无显著影响;随网下配售比例的增加,抑价率呈现先下降后上升的趋势,在达到某一临界值后影响消失;当参与询价的乐观者网下申购数量超过网下配售数量时,减少锁定期不影响抑价率,但低于该数量时,减少锁定期会导致抑价率下降;当参与询价的乐观者比例与网下配售比例一致时,抑价率最低。随后的实证分析结果与理论分析一致。最后,提出取消网下配售比例等建议,以推进IPO定价制度市场化改革。

英文摘要：

We establish a theoretical model to explore the impact of the range of inquiry recipients, the proportion of offline rationing and lock-up period on IPO underpricing, and test empirically the theoretical results using the international IPO data. Theoretical results are as follows. （1） Underpricing decreases first and increases later with the range of inquiry recipients widening after a certain threshold. （2） Underpricing decreases first and increases later with increasing of the proportion of offline rationing, and the effect disappears after the proportion of offline rationing reaching a certain threshold. （3） Reducing lock-up period does not affect underpricing when the optimists~ net purchase exceeds quantities of offline rationing, while if less than the quantities of offline rationing, the reducing lock-up period may decrease underpricing. （4） Underprieing becomes the lowest when the proportion of optimists in the inquiry is close to the proportion of offline rationing. The empirical results are consistent with theoretical results. Finally, we propose to abolish the requirement of the proportion of offline rationing in order to promote market-oriented reforms of IPO pricing mechanism.