利用2003年12月8日我国沪、深两市提高交易前市场透明度这一“自然实验”,考察市场透明度变化对我国股票市场运行效率的影响.研究发现交易前市场透明度提高后,沪、深两市的市场质量总体上都得到显著改善,具体表现为:价格信息效率显著提高,市场流动性显著增强,价差中信息不对称的成分呈逐月减少的趋势,股价波动性先升后降.研究结果表明:沪、深两市提高交易前市场透明度的改革举措有助于改善市场运行效率.
Shanghai Stock Exchange and Shenzhen Stock Exchange increased the real-time public dissemination of limit order book from the 3 best ask and bid quotes to 5 best on December 8, 2003. This paper studies the effects of this event to improve transparency on the market quality. The authors find that informational effi- ciency of price is improved, the market liquidity increases, volatility of the price decreases and the component of asymmetric information in the bid-ask spread is reduced after the two markets adopt action to improve transparency.