The conclusions made in this study are still tentative, and several issues remain open to scrutiny. Above all, the instrumental variable approach in this study has only been applied to the analysis using a TEL dummy. The potential endogeneity problems have not been addressed using alternative measures of TELs such as potentially binding and nonbinding TELs, and specific types of TELs, due to the difficulty of finding appropriate instruments. Since this study finds evidence suggesting the importance of recognizing the endogenous nature of TELs, further research should focus on developing appropriate instruments for the imposition of TELs.