The fact that the cost of debt finance is tax deductible, whereas the cost of equity is not, seems to give a structural advantage to debt finance. The value (if any) of this ‘tax shield’ is either an explicit or more likely implicit component of any equity valuation. The most commonly quoted calculation of the value of the debt interest tax shield understates value by ignoring growth but overstates value by ignoring the effect of personal taxes. We explain how to incorporate these often-i...
