中文摘要：

近年来，企业如何根据股票市场定价偏差选择有利的融资发行时机成为企业融资结构研究的热点问题之一。目前研究主要以市值账面比（M／B）作为股票定价偏差代理变量，然而市值账面比指标引起学术界很大争议，研究结论缺乏可靠性。本文根据中国股票市场高流动性特征选择股票换手率作为股票估价偏差变量，实证检验了股票换手率与企业外部融资发行时机的关系，以及对资本结构变动的影响途径和持续性。检验结果显示，股票换手率与权益融资具有显著的正相关关系，与债务融资负相关，但并不十分显著，表明中国上市公司确实存在股权融资的市场择时行为；股票换手率主要通过股权融资和股票收益对资本结构具有显著的负向影响，并可以持续到4至5年之久。研究结论表明，企业在股票价格高估时发行股权融资，低估时选择回购股票或发行债务融资，当前资本结构是企业过去融资发行市场时机的累积结果。

英文摘要：

Recently, the hot issue of capital structure has been how firms choose the favorable financing issuing timing according to the price fluctuations of stock markets. The current empirical study is based on the market-to-book as the market timing variables. However, there exists much controversy on market-to-book, and the conclusion lacks reliability. According to the characteristics of China＇s capital market, this paper chooses the shares turnover as the market timing variables to examine empirically the correlation between share turnover and exterior financing issuing timing, and the effects on leverage change approach and persistence. The evidence shows that share turnover is positively related to equity issues, but negatively related to debt issues. We find that share turnover has strongly negative effects on the change of leverage, which can sustain over 4 to 5 years. The result of this paper demonstrates that firms are more likely to issue equity when their market values are high, and repurchase equity or issue debt when their market values are low. So, the current capital structure is the cumulative outcome of past attempts to time the equity market.