Trump is placing a 25% tariff on imported steel and 10% on imported aluminum. The tariffs will go into effect at midnight.
Investors worry that trade restrictions will raise costs and dent profits for companies that rely on the materials to produce their goods.
Wall Street is also on edge about retaliation.
Stocks plunged after Canadian Prime Minister Justin Trudeau announced steel and aluminum tariffs against the United States. Europe and Mexico also announced plans for countermeasures.
In addition, the Trump administration is pushing ahead with plans for tariffs on $50 billion worth of Chinese goods as punishment for intellectual property theft.
“Uncertainty surrounding tariffs on Chinese imports is a source of concern for some retailers that have operations overseas or use imported goods,” the Federal Reserve Bank of Cleveland said in a report on Wednesday.
The stock market is having a turbulent week. The Dow lost nearly 400 points on Tuesday