The existence of pre-tax cost of debt and post-tax cost of debt is due
to the acknoledgement of the tax benefit from issuing debt.There is no
tax benefit from paying divdends,so it makes no sense talking about
pre-tax,post-tax cost of equity for a firm.When you think about cash
flow to equity you can only assume that the taxes owed by the company
have already been paid.Now, the taxation over the income of the
shareholder is a whole different issue that does not take place in this
discussion,since it is not taken in consideration either in cost of
equity or cost of debt.
