An interesting idea out of the US for how to fairly tax multinationals around the world:
First, have them declare a worldwide profit, netting off worldwide sales and worldwide qualifying expenses1
Second, find out where they made their sales.
Third, apportion the profit to various jurisdictions based on whatever portion of the sales took place in that country.
So if Facebook made $10 billion worldwide, and made 30% of its sales in the USA, then the US government would collect tax from Facebook on the basis of a $3 billion nominally-USUS profit.
I’m sure there are issues to iron out, and you’ll need good multilateral government cooperation to make it work. But this kind of international cooperation sounds a lot fairer to me than an international race-to-the-bottom on corporate tax rates.