This paper provides a snapshot for the impact of concentrated ownership on corporate governance, focusing on the study of concentrated ownership structures. The study found that interaction between the corporate feature and the prevailing pattern of concentrated ownership affect the effectiveness of corporate governance and the level of voluntary disclosure. The role of owners in determining the level of voluntary disclosure depends on the efficiency of the owners' supervisory role on the activities of the company. In addition, the degree of ownership concentration affects both the supervisory role of the owners and the level of governance applied in the company.