Selling on the New York Stock Exchange Monday morning touched levels considered panic-like by technical traders, as the Dow Jones Industrial Average DJIA, -0.87% slumped more than 2,000 points, or 7.3%. The Arms index on the NYSE hit around 2.067 Monday morning and had been at 2.46. The decline in the S&P 500 index SPX, -1.11% , off 7%, triggered an initial circuit breaker, which resulted in a 15-minute halt in trading, a tumble in crude-oil prices and worries about coronavirus have rocked stocks. The ARMS index is a volume-weighted breadth measure, that tends to rise when the broader market falls, as the intensity of the selling in declining stocks is usually greater than the intensity of buying in rising stocks. Levels above 2.000 are considered panic-like activity. The S&P 500 was sinking 7.3% at 2,754, while the Nasdaq Composite Index COMP, -1.07% was down 7.1% at 7,972. A second circuit breaker would be triggered if the S&P 500 fell by 13% before 3:25 p.m. to trigger a second trading halt, which would also last 15 minutes.