Establishing bounds on the tax advantage to debt

The partial dismantling of the imputation tax system that commenced in July 1997 once more opens the discussion on the relative tax advantage to debt and its impact on the cost of capital. In this paper we examine the implications of these recent changes for the value of the tax advantage to debt. We analyse the value of debt-related tax shields by computing the individual tax liabilities of 1268 quoted companies that reported during the period 1980-2000 taking account of any tax exhaustion or surplus ACT. We use these estimates to establish an upper bound on the tax advantage to debt. We conclude that even following the 1997 changes in the imputation tax system the probable value for the average current tax advantage to debt in the UK at present is at most about 13% of the value of debt.