摘要：多元化与公司绩效之间的关系是一个在理论界颇具争议的话题，到目前为止学术界对其关系仍然没有统一的定论：有的学者支持多元化溢价论，即通过施行多元化的战略，可以促进公司的发展，提高公司业绩。有的学者认为多元化折价论，他们认为多元化会阻碍公司的发展，降低公司业绩。也有的学者提出了多元化中性论，说明了多元化和公司绩效并没有显著的关系。综上所述，本文在文献综述部分尽可能详细的对多元化和公司绩效的研究成果进行了回顾，并按照以往得出的不同结论进行了归纳和分类。

　　随着民营企业的不断壮大，现在已经发展成为我国经济中不可或缺的重要组成部分，无论是从企业的产值、数量、市场零售额，还是从税收贡献、出口创汇、从业人员等来看，民营企业都已经成为支撑国家经济和社会发展的重要力量。面对现在社会激烈的竞争，不少民营企业试图通过实施多元化来扩大规模和快速实现资本化升值。正因为民营企业在经济当中的重要性，以及多元化经营和公司绩效之间关系的复杂性等问题，所以本文以江苏省民营上市公司为样本，考查企业多元化经营与公司绩效之间的联系。

　　本文选取了154家江苏省民营上市公司为研究样本，利用其公布的2011年的公司年报和CCER数据库所提供的财务数据，选取赫芬达尔指数和专业化率来衡量企业的多元化程度，选取ROA，Tobin’s Q和TFP来衡量公司绩效。本文同时选取托宾Q值和TFP作为衡量公司绩效的指标，分别研究了多元化经营对于公司市场价值和企业全要素生产率的影响，因此更有具体的现实意义和研究价值。此外，本文重点分析了多元化程度和TFP的关系，这是因为TFP与ROE和ROA相比，不容易受到受操控的财务指标的影响，能够更客观的衡量一个公司能否持续发展。

　　通过多元回归模型的计量检验，本文发现，江苏省民营上市公司目前的多元化经营和Tobin’s Q之间存在着弱的正相关关系，多元化经营与ROA之间存在弱的负相关关系，以及多元化经营和TFP之间存在着显著负相关关系。这说明目前的民营上市公司多元化经营仅能有助于公司市场价值的提高，这可能是民营上市公司为了实现快速资本化升值而采取的策略；但是，在资本市场不完善的条件下，目前的多元化经营对于公司长期绩效或者是生产效率的影响是负向。最后，本文给出了针对性的建议。与此同时，也指出了本次研究的不足以及后续研究方向。

关键词：多元化；公司绩效；民营上市企业；全要素生产率

ABSTRACT：The relationship between diversification and corporate performance is a controversial topic in the theoretical world, their relationship still has no uniform conclusion: Some scholars support the theory of diversification premium, namely, through the implementation of a wide range of strategies, diversification can promote the development of the company, which means diversification is able to improve the performance of the company. On the other hand, some scholars argue that the diversification discount theory has more important position; they believe that the diversification will hinder the development of the company, reducing the performance of the company. Some scholars have also claimed diversified neutral theory, that is to say diversification and corporate performance have no significant relationship. Combined with the above, the essay has concluded the literature review section on diversification and corporate performance in detail, summarized and classified in accordance with the previously drawn different conclusions.

　　　With the growing of private enterprises, they have now developed into an indispensable part of our economy, whether from the output value of enterprises, the number of retail market, or from the tax contribution, export and employing , private enterprises have become an important force to support the national economy and the social development. In face of intense social competition, many private companies are trying to expand the scale and improve the competitiveness of survival through the implementation of diversification. Under this circumstance, the essay chooses private listed companies in Jiangsu Province as a sample to study the relationship between diversification and corporate performance.

　　　Selecting 154 private listed companies in Jiangsu Province on its published 2011 financial information and CCER, we got required statistics. Further, we select the HI and SR (specialization rate) to measure the degree of diversification, select the ROA, Tobin’s Q and TFP to measure corporate performance. Focusing on the relationship between the degree of diversification and TFP, which is vulnerable to manipulation and ROA and ROE financial indicators, TFP is more important to a company's ability to continue as a more objective evaluation index. Therefore, TFP growth is the only source of sustainable profitable growth. This paper selects the TFP as one of the indicators to measure the performance of the Company, more definite practical significance and research value. We joined the company size, listed life, asset-liability ratio, operating cash flow per share and shareholders stake as control variables. 

　　　By analyzing China's Jiangsu Province private listed companies diversified overall understanding, come to the diversification of listed companies and Tobin's Q of a significant positive correlation between ROA was not significant negative correlation between TFP significant negative correlation relationship, the other conclusion is that the size of the company has a significant positive impact on corporate performance, the greater the size of the company, the better the performance of the company. Finally, this paper presents useful recommendations. At the same time, it pointed out the lack of this study and further research direction.

Keywords: diversification; corporate performance; private listed company; TFP