Capital Structure Decisions Under Classical and Imputation Tax Systems: A Natural Test for Tax Effects in Australia

The paper investigates determinants of capital structure, focusing on tax incentives for debt. The paper makes use of a panel of Australian firms in two tax regimes: a classical regime, and a dividend imputation regime. An important feature is the identification of the economic model using Bayesian selection methods. This methodology offers a new way of examining and assessing interactions between variables where there are competing explanations, noisy data and no unifying theory. As hypothesized, the results demonstrate a significant tax coefficient during the classical era and an insignificant tax coefficient in the imputation era. Risk and signalling variables, represented by firm size, Z-score, operating risk and asset base are also found to help explain capital structure choice.