Aswath Damodaran Session 18 (MBA): The Cost of Capital and Optimizing Debt
In this session, we continued our discussion of the cost of capital approach to deriving an optimal financing mix: the optimal one is the debt ratio that minimizes the cost of capital. To estimate the cost of capital at different debt ratios, we estimated the levered beta/ cost of equity at each debt ratio first and then the interest coverage ratio/synthetic rating/cost of debt at each debt ratio, taking care to ensure that if the interest expenses exceeded the operating income, tax benefits would be lost. The optimal debt ratio is the point at which your cost of capital is minimized. Using this approach, we estimated optimal debt ratios for Disney (40%), Tata Motors (20%), Vale (30% with actual earnings, 50% with normalized earnings), Baidu (10%) and Bookscape (30%). Disney was underlevered, Tata Motors was over levered and Bookscape was at its optimal. We closed the class by looking at an extension of the cost of capital approach, which allowed us to bring in expected bankrutpcy costs into the discussion.