March 22 (UPI) -- The Dow Jones industrial average fell more than 700 points Thursday after President Donald Trump announced tariffs against China.
The Dow was down 724 points or 2.9 percent by the end of trading, the fifth-largest point decline in history after Trump signed a a presidential order to impose new tariffs on about $60 billion worth of imported Chinese products.
Trump said the tariffs were meant to stem "economic aggression" by Beijing.
The drop on Thursday was the largest since a historic 1,032-point drop in February, as the tariff announcement caused concern with investors.
"A global trade war, whether it's real or perceived, is what's weighing on the market," Ian Winer, head of equities at Wedbush Securities," told CNN Money. "There's this huge uncertainty now. If China decides to get tough on agriculture or anything else, that will really spook people."
The S&P index also dropped 2.5 percent Thursday along with the Nasdaq, which fell 2.4 percent.
Selling intensified at the end of trading Thursday by more than 250 points in the final hour, according to CNBC.
The Dow also fell 420.22 points on March 1, when Trump announced a 25 percent tariff on steel imports and a 10 percent tariff for aluminum.
"Trump's protectionism is making investors nervous," Dario Perkins, managing director of global macro at TS Lombard said. "Past experience suggests these policies are flawed, while even moderate trade barriers could disrupt today's complex global supply chains."
The stock market was also affected by losses in tech as Facebook faces probes by the Federal Trade Commission and multiple states regarding a breach in which data analytics firm Cambridge Analytica collected more than 50 million Facebook users' private information without permission.