Capital gains tax and the capital asset pricing model

This paper develops a version of the Capital Asset Pricing Model that views dividend imputation as affecting company tax and assumes differential taxation of capital gains and ordinary income. These taxation issues aside, the model otherwise rests on the standard assumptions including full segmentation of national capital markets. It also treats dividend policy as exogenously determined. Estimates of the cost of equity based on this model are then compared with estimates based on the version of the CAPM typically applied in Australia, which differs only in assuming equality of the tax rates on capital gains and ordinary income. The differences between the estimates can be material. In particular, with a high dividend yield, allowance for differential taxation can result in an increase of two to three percentage points in the estimated cost of equity. The overall result obtained here carries over to a dividend equilibrium, in which firms choose a dividend policy that is optimal relative to the assumed tax structure.