中文摘要：

如何提高投资者法律保护的执法效率是近年来财务学研究的热点问题，也是资本市场能否健康有序发展的一个关键因素。本文以2000--2010年沪深两市因违规受到处罚的A股上市公司为样本，从处罚公告前监管部门的查处及时性、处罚公告前后高管被迫离职、处罚公告时的市场反应三个维度，深入考察政治关联是否影响中小投资者法律保护的执法有效性。研究发现：（1）监管部门对政治关联公司的违规查处存在时滞效应，其惩处周期显著长于无政治关联公司；（2）在处罚公告前一年和后一年，政治关联公司高管的被迫离职率均显著低于无政治关联公司；（3）违规处罚公告时，政治关联公司的负向市场反应大于非政治关联公司，且这种现象主要表现在国有样本里。这说明，政治关联会削弱中小投资者法律保护的执法效率，且“违规查处及时性”和“高管变更”是两种重要的影响路径。

英文摘要：

How to improve the legal enforcement efficiency to protect minority share- holders is a hot issue in finance. Using a sample of 383 regulatory enforcements by CSRC be- tween 2000 and 2010 in China, this paper investigates the effect of political connections on the efficiency of legal enforcement from three perspectives： time to identify and prosecute securi- ties fraud, top managers＇ turnover and market reaction. Firstly, we find that the time to i- dentify and prosecute securities fraud in political-connected firms is longer than that in non- political-connected firms. Secondly, in the one year period before and after the CSRC＇s en- forcement actions, we find a significant lower managerial turnover for political-connected firms than for non-political-connected firms. Finally, the market reaction to revelation of fraud in political-connected firms is more negative than that in non-political-connected firms. And this result is more significant in state-controlled firms. These results suggest that politi- cal connection weakens the efficiency of legal enforcement. And timeliness of fraud prosecu- tion and top managers＇ turnover are two main mechanisms through which political connections influence the efficiency of legal enf6rcement.