The European Union is already said to be drawing up a list of proposed retaliatory tariffs on U.S. products. And a White House official says that more than 50 countries have contacted the administration so far to start negotiations on the import duties.

From Jamie Dimon to Bill Ackman, business leaders say the shifting landscape on global trade could undermine economic growth and stymie corporate profits.

Asian markets plunged on Monday following last week’s two-day meltdown on Wall Street, and President Donald Trump said he won’t back down on the sweeping new tariffs he announced on April 2 that have