A simple counterexample shows the the widely used WACC approach to value leverage firms developed by Miles and Ezzell can create an arbitrage opportunity. The only consequence to be drawn is that their WACC approach cannot be applied under the circumstances assumed by Miles and Ezzell.

We extend the WACC approach to a tax system having a firm income tax and a personal income tax of the investor as well. We use an artificial tax system incorporating most of the G-7 national tax codes as for example the classical or the imputation systems.

It is well-known that stock prices fluctuate far more than dividends. Traditional valuation methods are not able to depict this fact. In this paper we incorporate excess volatility into a simple DCF model by considering an autoregressive cash flows process with random coefficients. We show that...