本研究以完成民營化之十八家上市公司為研究對象，衡量其民營化後三年之經營績效與長期投資績效。首先以五項財務指標衡量經營績效，再以買進持有異常報酬與累積異常報酬來衡量投資績效。最後考慮大股東、董監事、經理人、及政府持股比率、是否為民營化當年度、產業別、民營化前一年績效及國民生產毛額成長率等變數，將上述自變數分別對經營績效與投資報酬作迴歸分析，以找出影響績效變動的因素。 結果顯示僅資產週轉率提升，且結果不顯著，故民營化後經營績效與長期股價異常報酬無法持續。在民營化後績效變動的影響因素，則僅大股東持股比率愈低或民營化前一年績效為較佳者，民營化後之經營績效與長期投資報酬較佳，但結果亦不顯著。民營化後董監事持股比率與政府持股比率，僅對資產週轉率有顯著的正及反向影響，其他因素則無法支持對民營化後績效之預期。

The performance of 18 listed privatized companies was evaluated for the period of three years after privatization. The evaluation of performance was classified into operating and long-term investment performance. Five financial ratios were used to measure the operating performance. In evaluating the long-term investment performance, the buy-and-hold abnormal return and cumulative abnormal return are measured. In order to find out the factors which influence the changes of performance, the percentage of shares held by individual investors, the percentage of shares held by directors, the percentage of shares held by managers, the percentage of shares held by government, the privatization year, the industry factor, the performance before the privatization year, and GDP growth rate were considered as independent variables to carry out the regression analysis. It is showed that only total assets turnover was increased after privatization but not significant. The factors influencing the performance show that the lower percentage of shares held by individual investors or the better the performance before the privatization year, the better operating performance and the long-term investment, but also not significant. The percentage of shares held by directors and government have positive and negative impact to the asset turnover.