The income of Puerto Rican affiliates of U.S. corporations is essentially untaxed by either Puerto Rico or the U.S. This lowers the tax penalty on real investment there, and also makes it attractive to shift reported taxable income from the U.S. parent corporation to the Puerto Rican affiliate....

We look at the tax burden on direct investment from three perspectives. The first section illustrates how the recognition of company tax planning and of the importance of intellectual property affects measures of effective tax rates. It also discusses the methodological issues that arise, such...