This study aims to examine and analyze the effect of the Investment Opportunity Set (IOS) on the corporation funding policies and also finds out whether or not the institutional ownership moderates the role of family ownership on IOS and company funding policies. The population includes all go-public companies listed on the IDX over the period 2008-2016. The sampling technique used was purposive sampling method. The processing data used regression equations with panel data models and Eviews analysis tools. The results show that IOS had a negative effect on the funding policies. This makes the company with a lower debt to equity ratio on its capital structure policy to use the equity financing to reduce the agency problems. Institutional ownership moderates the influence of IOS on the funding policies. This proves that the institutional ownership balances need to replace the role of debt in monitoring the managers and reducing the agency problems in the company. The family ownership does not moderate the influence of IOS on the funding policies because in the ownership, the family tends to take opportunities for the personal interests and form a weak ownership structure so that the agency problems rises and disrupts the company performance.