Private placement system has been implemented since February 2002 in Taiwan to cater for the financial need of enterprises. Previous studies indicate that the long-term performance of investment varies with different investors. The study, therefore, examines whether abnormal returns exist and how the investor types influence the long-term performance by analyzing 198 sets of data from private equity companies. Results show that one year later after private equity, abnormal returns significantly exist not only in all samples but also in active private placement cases. These findings are consistent with certification hypothesis and monitoring theory.