U.S. stocks plummeted on Thursday in a day of chaotic trading as investors sought shelter from potential economic consequences of coronavirus. The Dow Jones Industrial Average fell 4.4 percent, about 1,190 points. The Nasdaq Composite tumbled 4.6 percent. The S&P 500 declined 4.4 percent. It was the biggest one-day point drop in the history of both the Dow and the S&P, although far from the largest decline in percentage terms.