A broad-market rally late Monday also is coming with panic-like buying, market internal data show. The Nasdaq Arms Index, a volume weighted breadth measure, fell to 0.492 in afternoon trade. The Arms Index tends to decline below 1.000 when the broader market rises, as the intensity of buyers of advancing stocks increases relative to the intensity of sellers of declining stocks. The number of advancing stocks on the NYSE outnumbered decliners 2,002 to 823, or by a about 2.4-to-1 margin. Many see Arms readings below 0.500 as implying panic-like activity. The Nasdaq Composite Index COMP, +3.26% surged 229 points, or 3.3%, at 7,222, the Dow Jones Industrial Average DJIA, +2.84% jumped nearly 700 points, or 2.9%, at 23,223, while the S&P 500 index SPX, +2.72% surged 2.8% at 2,661. The gains for the S&P 500, Nasdaq and the Dow marked their sharpest in a session since August 2015.