This paper provides clear evidence of substantial tax effects on the choice between issuing debt or equity; most studies fail to find significant effects. The relationship between tax shields and debt policy is clarified. Other papers miss the fact that most tax shields have a negligible effect on the marginal tax rate for most firms. New predictions are strongly supported by an empirical analysis; the method is to study incremental financing decisions using discrete choice analysis. Previous researchers examined debt/equity ratios, but tests based on incremental decisions should have greater power.

This paper provides clear evidence of substantial tax effects on the choice between issuing debt or equity; most studies fail to find significant effects. The relationship between tax shields and debt policy is clarified. Other papers miss the fact that most tax shields have a negligible effect on the marginal tax rate for most firms. New predictions are strongly supported by an empirical analysis; the method is to study incremental financing decisions using discrete choice analysis. Previous researchers examined debt/equity ratios, but tests based on incremental decisions should have greater power.

A new empirical method and data set are used to study the effects of tax policy on corporate financing choices. Clear evidence emerges that non-debt tax shields "crowd out" interest deductibility, thus decreasing the desirability of debt issues at the margin. Previous studies which failed to find tax effects examined debt-equity ratios rather than individual, well-specified financing choices. This paper also demonstrates the importance of controlling for confounding effects which other papers ignored. Results on other (asymmetric information) effects on financing decisions are also presented.

James Levinsohn, Jeffrey K. MacKie-Mason, A Simple, Consistent Estimator for Disturbance Components in Financial Models, The Review of Economics and Statistics, Vol. 72, No. 3 (Aug., 1990), pp. 516-520