The Dow Jones Industrial Average was down more than 483 points in afternoon trade on Monday, on the back of nagging concerns about the threat of trade clash between the U.S. and its global trade partners morphing into a full-blown trade war. The Dow DJIA, +0.32% , most recently, was down 2%, or about 487 points, at 24,093 and falling below its 200-day moving average, seen as a long-term line in the sand by market technicians. Boeing Co.'s shares BA, -3.60% , off 3.1%, were producing the stiffest headwind for the blue-chip gauge, exacting a roughly 70-point toll from the price-weighted Dow. Boeing is among the companies seen as sensitive to trade disputes, due to the international nature of its business. A fall greater then 425 points or 1.7%, would represent the benchmark's worst daily decline since a 572-point, or 2.3%, fall on April 6. Meanwhile, technology stocks were particularly under pressure on word that President Donald Trump planned to bar many Chinese companies from investing in U.S. technology firms. The Nasdaq Composite Index COMP, +0.77% was down 2.8% at 7,481, on track for the worst session since April , while the S&P 500 index SPX, +0.48% was down 2% at 2,700.