中文摘要：

民营上市公司的政治关联这一非正式制度在给企业带来融资便利和税收优惠等优势的同时，也会降低其盈余质量。不同于以往的研究，本文主要关注民营上市公司这种政治关联的不利影响。我们以2004—2011年民营上市公司为研究样本，研究发现，政治关联无法在事前屏蔽证券监管，不能降低民营上市公司受到证券行政监管的概率。但是，由于证券行政监管执行力的不足，虽然民营上市公司受到证券监管机构的违规公告后盈余质量得到提升，但是政治关联削弱了行政监管对盈余质量的改善程度。本文的研究结果表明，民营上市公司普遍存在的政治关联降低了其提供高质量会计信息的动机，增加了信息风险，还间接削弱了证券行政处罚事后的治理效应。

英文摘要：

Political connection of private listed companies, acting as an informal institution, brings about advantages like financing convenience and tax preference but also lowers their earnings quality. Different from previous studies, this paper concentrates on the adverse effect of political connection. Taking private listed companies from 2003 to 2011 as research sample, our empirical study discovers that political connection cannot shield securities supervision beforehand or lower company＇s possibility of being subject to stock administrative supervi- sion. Considering the inadequate implementation of stock administrative supervision, though private listed com- panies enhance their earnings quality after security supervision institutions＇ violation announcement, political connection impairs the degree of such enhancement. Our research results show that the widespread political connection in private listed companies lowers their motivation to provide high - quality accounting information, increases information risk and indirectly impairs the afterwards governance effect of administrative sanctions.