A selloff in Monday afternoon trade reached levels not seen since early February by one measure. The Arms index is was at its highest since on the NYSE briefly hitting above 2.6, approaching its highest level since Feb. 5, when the markets saw another sharp descent, according to FactSet data. The Arms index is a volume-weighted measure of market breadth, 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, was at 2.621 on the NYSE. It last traded at 2.516. Levels above 2.000 are considered panicky. The Dow Jones Industrial Average DJIA, -1.90% ended off its lows, but still booked a loss of about 460 points, or 1.9%, at 23,644 in Monday afternoon trade. The S&P 500 index SPX, -2.23% ended off 2.2% at 2,581, below its 200-day moving average, while the Nasdaq Composite Index COMP, -2.74% turned negative for the year and for the session, off 3.2% at 6,836. The number of advancing stocks on the NYSE outnumbered decliners 2,378 to 567, or by around a 4.2-to-1 margin.