Many commentators believe that the higher the percentage of independent directors and supervisors, the better the financial performance of firms. A competent authority in Taiwan requested that newly listed companies should hire independent directors and supervisors after February 22nd, 2002. However, the empirical results in this paper challenge the conventional point of view on this topic in the literature. And in addition, this study finds that the promulgation of the 2002 regulation has brought with it some negative effects. First, the results of this study suggest that the percentage of independent directors and supervisors has a nonlinear relationship with firm performance. Second, the empirical findings of this study show that, affected by the new regulation, some bad companies that didn’t have to follow the new regulation will still voluntarily hire independent directors and supervisors in order to prevent investors from discovering their true quality. Finally, in this paper, we also find that the quality of the independent directors and supervisors is very important for firm performance and should be requested more completely and strictly to make sure that the monitoring mechanism of the firm really works.