I think the difficulty with corporation tax for global corporations is that asking where profits are generated is not the only relevant question. You could als

I think the difficulty with corporation tax for global corporations is that asking where profits are generated is not the only relevant question. You could also ask who bears the cost of generating those profits. Where did Apple's employees grow up and go to school before they joined Apple in California? Who builds the infrastructure for manufacturing and distributing Apple's products? So the global distribution of value generation and the global distribution of cost can vary significantly. In fact, Apple is a relatively simple case compared to, say, Amazon. Of course, this doesn't make the sort of "tax planning" you're talking about any less problematic. On the contrary.