SUMMARY
Previous researchers found that managers have conducted opportunistic earnings management (Abdolmohammadi et al., 2010; Crocker and Slemrod, 2007;Cornett et al., 2009; Jaggi et al., 2009). Corporate Governance (CG) is one of the instruments to overcome, or at least to minimize, earnings management. This research aims to provide empirical evidence about the effect of CG and earnings management on firm value, and the role of CG in the effect earnings management has on firm value. This research is needed, to explain the effectiveness of CG’s implementation by influencing earnings management, in order to lead to more efficient earnings management.This study uses national commercial banks’ data listed on the Indonesian Stock Exchange for the period 2006-2013. The research sample consists of 29 banks over an 8 year period, with a total of232 observations. The research variable consists of the value of the firm, measured by Tobin’s Q as the dependent variable, real activity-based earnings management and accrual-based earnings management as the independent variables and corporate governance, measured by the CG index, as a moderating variable.The results show that the CG index has a robust relationship with performance, controlled by both the ownership concentration’s level and the size of the bank. Corporate governance has positive effects on firm value. The bigger the corporate governance disclosure score is, the higher the market value of the bank becomes. These results indicate that markets respond to the corporate governance’s disclosure, so the company’s market price increases. The results show that the CG index reinforces the positive influence of Accrual-based Earnings Management (AEM) and Real Earnings Management (REM) on the performance. These results indicate that corporate governance practices are able to steer earnings management away from the opportunistic and into the efficiency spectrum.