Wall Street has tanked, ending the longest-ever US bull market after new travel restrictions to curb the coronavirus outbreak spooked investors and rattled world markets.

The Dow Jones Industrial Average fell 2,352.33 points, or 9.99 per cent, to 21,200.89, the S&P 500 lost 260.75 points, or 9.51 per cent, to 2,480.63 and the Nasdaq Composite dropped 750.25 points, or 9.43 per cent, to 7,201.80.