Basically, two approaches to the valuation of a levered stream have appeared
in the literature. The textbook approach assumes a constant cost of
equity, a constant cost of debt, and a constant leverage ratio. The Modigliani
and Miller approach assumes a constant unlevered cost of capital and a constant
cost of debt. The adjusted present value model developed by Myers is a normative
implication of the MM valuation approach. Our analysis shows that the
textbook approach is also an implication of the MM approach and is, therefore,
a special case of Myers' MM-based APV model.