我國新上市公司上市後經營績效大幅衰退之現象時有所聞，而上市後董 監事即拋售股票並申請現金增資之情形亦不在少數，嚴重影響投資人之權益。儘 管媒體對這方面之報導頗多，然迄今學術界仍乏有系統之分析研究，本文盼能拋 磚引玉，激勵往後更多之探討。 本文旨在分析新上市公司是否上市之後經營績效變差，其次本文亦嘗試瞭解影響 績效變化的相關因素。本研究採用股東權益報酬率、營業利潤率、資產報酬率作 為績效衡量指標。樣本包括74年至80年底計103家新上市公司，以上市前三年的 平均為分析上市後經營績效是否衰退之比較基礎。 本研究首先測試樣本公司上市前後經營績效之差異，並調整同業平均數。其次， 將樣本分別按會計師聲譽、承銷商聲譽、上市期間、董監持股變動率及現金增資 率分為兩組，以單變量分析檢定兩組績效變化是否不同。最後以複迴歸分析，同 時考慮上述五個因素及兩個控制變數對上市後經營績效之影響。 本研究實證結果顯示，調整產業平均後，樣本公司上市三年內相較於上市前三年 平均確實有顯著衰退之現象。而影響績效衰退之相關因素中，承銷商聲譽及現金 增資之多寡有較佳的解釋力，其他變數雖然與預期符號相同，但不顯著。

　　　　　There have been many reports indicating that the operating performance of newly listed firms in Taiwan Stock Exchange has declined by a big margin. Also, officers and directors of these firms are reported to sell large shares right after initial public offering. Further, these firms often attempted to raise capital by issuing new shares shortly after listing. However, so far there exists noempirical studies that systematically examine the above issues, which motives this research. The main purpose of this paper is to investigate whether newly listed forms really perform poorly after the listing. This study also tries to analyze factors that may affect the operating performance of these firms. Return on owners' equity, profit margin on sales, and return on assets are employed as proxies for performance measurements. The sample examined consists of 103 newly listed firms from1985 to 1991. This study uses there years' average before the listing as benchmark for analysis of post listing operating performance. This study uses both univariate and multivariate analyses to test the proposed hypotheses. The empirical results do support the hypothesis that newly listed firms perform worse soon after the listing, after adjusting for industry average. With regard to the factors affecting the performance, quality of underwriter and percentage of new capital raised in the post-listing period are found to have significant relationship with degree of poor performance.