مالیات بازتوزیعی، شرکت های چند ملیتی و یکپارچگی اقتصادی

Increased activity of multinational firms exposes national corporate tax bases to cross-country profit shifting, but also leads to rising profitability of the corporate sector. We incorporate these two effects of economic integration into a simple political economy model where the median voter decides on a redistributive income tax rate. In this setting economic integration may raise or lower the equilibrium tax rate, and it is more likely to raise the tax rate of a low-tax country. The implications of the model are consistent with the empirical observations that effective corporate tax rates have not fallen in all OECD countries, and that corporate tax revenues have generally risen.

One of the most pronounced trends in the world economy over the last decades has been the rise in foreign direct investment and multinational activity. In the United States, for example, foreign profits made up around 5% of all corporate profits earned by U.S. firms until the late 1960s, but this share has meanwhile risen to more than 25%, and is probably even higher (Desai and Hines, 2004). As a consequence of this development national corporate tax bases have become more sensitive to tax changes.1 Most of the literature on international tax competition has therefore modelled economic integration as a pure increase in the mobility of the capital tax base. In these models the typical result is that increasing capital mobility leads governments to undercut each other's capital income tax rates, resulting in underprovision of public goods as well as relatively higher taxes on immobile factors (see Wilson, 1999 for a survey). Empirical evidence in support of this theoretical prediction is mixed, however. Table 1 summarizes the development of corporate tax rates and tax revenues in a representative sample of OECD countries. Two stylized facts stand out. First, statutory corporate tax rates have been significantly reduced in most OECD countries since the 1980s, but tax bases have simultaneously been broadened. As a consequence, effective tax rates on profits have fallen by much less than statutory rates, and in several countries they have not fallen at all.2 Second, an even more significant deviation from the standard theory of tax competition arises with respect to the development of tax revenue as a share of GDP. Corporate tax revenue has increased significantly in most countries since the early 1980s, despite the average fall in effective tax rates.3

This paper has started from two fundamental effects that are associated with the rise in foreign direct investment and multinational firm activity. In contrast to nationally operating firms, multinationals have the opportunity to shift profits to low-tax countries, but they are also more profitable and thus raise the aggregate profitability in the corporate sector. Incorporating these facts into a simple political economy model we have shown that economic integration increases the efficiency cost of capital taxation, but it also increases the redistributive benefits of the tax from the perspective of the median voter. This result may help in explaining why several OECD countries have not reduced their effective rates of corporation tax since the 1980s. Moreover, our model implies that corporate tax revenues may rise despite falling tax rates, a finding that is consistent with the experience of the majority of OECD countries during the last decades. It goes without saying that the model put forth in this paper is stylized in many respects. In particular, core simplifications have been the assumptions of exogenous factor prices and productivity gains from a multinational operation, and the modelling of the (personal and corporate) income tax system through a single, proportional tax rate. We would argue, however, that the basic effects outlined above would still be present in a more complex model. At the same time we believe that incorporating a more detailed modelling of multinational firms into the analysis of taxation and other government policies is a promising area for further research.