The answer is to tax multinational profits where real economic activity happens -- known as unitary taxation. Revenue simply shifts from tax havens where profits are "booked" to the countries where workers produce and customers spend. Making that principle a global tax standard depends on United Nations talks opening in New York on Monday. What the report calls "diversified" tax havens such as Switzerland and the Netherlands could offset losses by raising rates. One protocol would let countries tax digital and other cross-border services without waiting for firms to establish domestic offices, blunting Mr Trump's trade threats.