Firms with concentrated ownership structures are commonly found in Southeast Asia. In Indonesia, the biggest control of the firm comes from the family. Concentrated ownership can lead to agency problem between controlling shareholders and non- controlling shareholders where, controlling shareholders together with management, can make decisions which bring personal benefit at the expense of non-controlling shareholders for example by investing on projects with negative NPV or known as overinvestment. This study explains the effect of the presence of directors and independent commissioners on relationship between family ownership and overinvestment. Using firms listed on Indonesia Stock Exchange from 2011 to 2017 as research samples, the presence of independent director is negatively related to overinvestment. From the regression results, only independent directors were found to have a moderating effect in weakening the positive relationship between family ownership and overinvestment. This effect is seen more clearly if family ownership in the company is low. This is because if family ownership in the company is low the process of selecting a board of directors can be more objective so that the possibility of a number of independent directors sitting on the board of directors is much greater. Thus the effect of moderation by independent directors will be greater in companies with lower family ownership.
Keywords: ownership structure, board independence, overinvestment, corporate governance, Indonesia