This paper presents a model of a multinational firm's optimal debt policy that incorporates international taxation factors. The model yields the prediction that a multinational firm's indebtedness in a country depends on a weighted average of national tax rates and differences between national and foreign tax rates. These differences matter because multinationals have an incentive to shift debt to high-tax countries. The predictions of the model are tested using a novel firm-level dataset for European multinationals and their subsidiaries, combined with newly collected data on the international tax treatment of dividend and interest streams. Our empirical results show that corporate debt policy indeed not only reflects domestic corporate tax rates but also differences in international tax systems. These findings contribute to our understanding of how corporate debt policy is set in an international context.

This paper explores how corporate taxes affect the financial structure of multinational banks. Guided by a simple theory of optimal capital structure it tests (i) whether corporate taxes induce subsidiary banks to raise their debt-asset ratio in light of the traditional debt bias; and (ii) whether international corporate tax differentials vis-a-vis foreign subsidiary banks affect the intra-bank capital structure through international debt shifting. Using a novel subsidiary-level dataset for 558 commercial bank subsidiaries of the 86 largest multinational banks in the world, we find that taxes matter significantly, through both the traditional debt bias channel and the international debt shifting that is due to the international tax differentials. The latter channel is more robust and tends to be quantitatively more important. Our results imply that taxation causes significant international debt spillovers through multinational banks, which has potentially important implications for tax policy.

Tax provisions favoring corporate debt over equity finance (“debt bias”) are widely recognized as a risk to financial stability. This paper explores whether and how thin-capitalization rules, which restrict interest deductibility beyond a certain amount, affect corporate debt ratios and mitigate financial stability risk. We find that rules targeted at related party borrowing (the majority of today’s rules) have no significant impact on debt bias—which relates to third-party borrowing. Also, these rules have no effect on broader indicators of firm financial distress. Rules applying to all debt, in contrast, turn out to be effective: the presence of such a rule reduces the debt-asset ratio in an average company by 5 percentage points; and they reduce the probability for a firm to be in financial distress by 5 percent. Debt ratios are found to be more responsive to thin capitalization rules in industries characterized by a high share of tangible assets.