A new batch of tariffs from President Donald Trump on Tuesday again sent some investors scrambling, as the blue chip Dow Jones Industrial Average stock index tumbled further as the market shudders at economic policy uncertainty.

But uncertainty around Trump's tariff policy continues to grip Wall Street, and his trade war has only intensified this week. The president has vowed to respond to tariffs planned by the EU and Canada in response to US duties on steel and aluminum imports — most notably leading off Thursday by threatening a 200% tariff on imports of EU wines and spirits.