The principle of world source income is justified by reasoning of economic efficiency, as well as by the need for tax systems to be neutral to achieve this objective. A tax system must be neutral and neutrality means that it should not influence the decision of the different economic agents, but rather that the placement of capital or the choice of activities to be developed follow a criterion of economic efficiency, understanding by such, the placement or use of resources in the place and / or activity where they are most productive.