The weighted average cost of capital is not quite right: Reply to M. Pierru

In this journal [Miller, R. A. (2009). The weighted average cost of capital is not quite right. The Quarterly Review of Economics and Finance, 49, 128–138], I argued that the standard WACC formula is inadequate in most circumstances to reward stockholders and bondholders where the necessary cash flows are calculated separately to exactly cover the respective costs of capital. Axel Pierru [2009. ‘The weighted average cost of capital is not quite right’: A comment. The Quarterly Review of Economics and Finance, 49, 1219–1223] observes correctly that my assumed repayment schedules (equal periodic payments to bondholders; similarly for stockholders) imply a temporal drift in the debt (or leverage) ratio; he would recalculate the WACC annually. He proposes an alternative calculation of the repayment schedules under the constraint of a constant debt ratio. Here I suggest three additional possible repayment schedules; in general repayment schedules determine the drift in the debt ratio. However, the expected repayment schedules are established at the time the project is accepted and financed, hence the relevant debt ratio is that which exists at that time. The WACC for a specific project need not (and should not) be recalculated for that project throughout its financial life when that project has already been accepted and financed.