深交所完善IPO股票上市首日盘中临时停牌制度的实际效果

The Real Effect of the Improvement of the Temporary Suspension System for IPO Shares in the First-day of Listing

IPO抑价及"炒新"在世界范围内普遍存在。所不同的是,深交所通过行政性手段及制度性方式对新股上市首日的涨跌幅及换手率进行了约束。为分析新股上市首日盘中临时停牌制度的实际效果,本文使用基因配对方法和Rubin因果推断模型分析《关于完善首次公开发行股票上市首日盘中临时停牌制度的通知》的具体影响后发现:《通知》尽管降低了上市首日的换手率,却推高了上市首日的个股回报率和市盈率;其实际上将新股上市首日的收盘价维持在较高水平,而无助于抑制炒新风险。

The phenomenon of IPO underpricing and new shares speculation listed on the first day is worldwide universal.What is different is that Shenzhen Stock Exchange makes an attempt to limit the price change and turnover rate of new shares listed on the first day through administrative means and institutional ways.In order to analyze its real effect,genetic matching method and Rubin causal model are employed to analyze the effect of newly announced ' The notice about the improvement of temporary suspension system for initial public offerings of shares in the first-day of listing'.The empirical results show that,although the notice lowers the turnover rate,it does push up the returns and PE.In fact,it keeps the close price in a relative high level,but is not helpful to restrain risk.