A recent Spanish tax reform granted regions the authority to set income tax rates, resulting in substantial tax differentials. We use individual-level information from Social Security records over a period of one decade. Conditional on moving, taxes have a significant effect on location choice. A one percent increase in the net of tax rate for a region relative to others increases the probability of moving to that region by 1.7 percentage points. Focusing on the stock of top-taxpayers, we estimate an elasticity of the number of top taxpayers with respect to net-of-tax rates of 0.85. Using this elasticity, a theoretical model implies that the mechanical increase in tax revenue due to higher tax rates is larger than the loss in tax revenue from the out-flow of migration. High-income taxpayers may be literally "worth their weight in gold" to the government where they reside.1 As a means of tax avoidance, individuals may move in response to tax differentials resulting from residence based local income taxes. earning 300,000 Euros, this amounts to a tax differential of 10,000 Euros. These disparities in regional top tax rates led the popular press to dub low-tax regions such as Madrid as "tax havens" or one of several "paradises on Earth."Research on migration requires linked data of individuals in the country of origin and destination, which is fairly complicated to obtain. 2 Exploiting sub-national variation is therefore an appealing alternative. However, personal income in most countries is taxed at the federal level and only a few countries tax personal income at the regional or1 The quoted phrase comes from Wildasin (2009), who writes: "at current prices ($900/oz.), an average adult male's weight-equivalent (190 lbs.) of gold is worth around $2.7 million. Under conservative assumptions about life expectancy and discount rate, the present value of taxes paid by very high income taxpayers can easily exceed this amount."2 Kleven et al. (2013) and Akcigit et al. (2016) are notable exceptions. They focus on selected subgroups of the population for which the authors have been able to assemble the information needed without access to individual income data linked across countries. Bakija and Slemrod (2004), Moretti and Wilson (2017) and Young et al. (2016) 4 We make several contributions relative to Young et al. (2016). First, we study migration patterns of the rich (above 90,000 Euros) and not just the very rich (millionaires). We also study migration in a setting where regional taxes are purely residence-based; in the United States, taxes may have a residence and employment-based component. Finally, we show heterogeneous effects by industry and occupation.
2we study migration using a random sample of population level administrative data for a complete panel of all regions in a country; Young et al. (2016) have similar data and a single state analysis includes Young and Varner (2011).5 This administrative data provides us detailed information on industry and occupation that allows us to determine the g...