US stock market tumbled as Dow Jones plunged 427 points, reacting to Trumps tariffs on Canadian steel and aluminum. The S&P 500 dropped 0.6%, while the Nasdaq Composite fell 0.1%, deepening its correction territory. Market fears rose as the White House imposed higher duties on imports, sparking concerns over a US economic slowdown. Meanwhile, Citigroup downgraded US stocks, and Delta Air Lines slashed earnings forecasts. Investors now await February's CPI and PPI data for economic clarity.