As an agent of shareholders, manager should maximize shareholders' wealth instead of her own benefit. However, manager may not manage firm's resources efficiently and chase her own interest at shareholders' cost. To minimize this agency problem, shareholder should monitor manager behavior strictly enough. How strictly shareholder monitoring activities influenced by firm's ownership structure. Diffused ownership structure causes low shareholder power to monitor manager and bad financial performance at next stage. Relationship between ownership structures of the firm and financial performance has been tested empirically by many researchers. This paper tow depth investigation for Indonesian case.