The purpose of this study is to investigate the effect of regulations governing the type of banking activities on the performance of the banking sector in developing countries during the period from 2000 to 2012. In this regard, the effects of non-bank financial and commerce activities restrictions on their capital adequacy ratio are measured. The GMM method has been used to analyze the data due to the endogeneity problem of variables. The results show that the strict restrictions on the banks' activities in the capital and insurance market do not have a significant effect on the capital adequacy ratio. In addition, the more the stricter activities restriction in the real estate sector, the more significantly improved the ratio of capital adequacy. In contrast, increased stringency in non-bank financial activities generally has a negative effect on capital adequacy ratio. Also, increasing the stringency of the restrictions on banking-commerce activities has a negative effect on the of capital adequacy ratio.