* The president has undermined the rule of law and has challenged court rulings through twitter. This gives me no confidence that if your US corporation was engaged in litigation, especially against the government, that the court's rulings would be respected or followed.
* Immigration policy - you would find it increasingly difficult to recruit foreign staff and could be stigmatised for hiring from outside the US.
* Pressure to be an 'all American company' - Similar to the above but with respect to outsourcing, there is a risk that if you became successful, the President could at any day tweet negatively about your company.
* Risk of war with the world.
I'm sure there's more but just some thoughts I've been having. What do other foreigners think?