Tax setting in a federal system:: The case of personal income taxation in Canada

In a decentralised tax system, the effects of tax policies enacted by one government are not confined to its own jurisdiction. First, if both the regional and the federal levels of government co-occupy the same fields of taxation, tax rate increases by one layer of government will reduce taxes collected by the other. Second, if the tax base is mobile, tax rate increases by one regional government will raise the amount of taxes collected by other regional governments. These sources of fiscal interdependence are called in the literature vertical and horizontal tax externalities, respectively. Third, as Smart (1998) shows, if equalisation transfers are present, an increase in the standard equalisation tax rate provides incentives to raise taxes to the receiving provinces. A way to check the empirical relevance of these hypotheses is to test for the existence of interactions between the regional tax rate, on the one hand, and the federal tax rate, the tax rate set by competing regions, and the standard equalisation tax rate, on the other hand. Following this approach, this paper estimates provincial tax setting functions with data on Canadian personal income taxation for the period 1982-1996. We find a significant positive response of provincial tax rates to changes in the federal income tax rate, the tax rates of competing provinces, and the standard equalisation rate (only for receiving provinces). We also find that the reaction to horizontal competition is stronger in the provinces that do not receive equalisation transfers.