The Nasdaq Composite's COMP, -2.74% 2.7% tumble Monday, amid broad selling in the technology sector and uncertainty surrounding trade policy, came with the most panic-like selling in nearly two years. The Nasdaq's Arms Index, a volume-weighted breadth measure that tends to rise above 1.000 when the market falls, spiked up to 2.238, while readings above 2.000 are viewed as having panic-like characteristics. The number of declining stocks outnumbered advancers 2,359 to 623, a 3.8-to-1 ratio, while volume of declining stocks outnumbered up volume 580.70 million shares to 67.20 million shares, about an 8.6-to-1 ratio. Monday's close was the highest since it closed at 2.32 on June 27, 2016 when the Nasdaq Composite plummeted 2.4% in the aftermath of the U.K.'s shock Brexit vote. After that, however, the Nasdaq kicked off a 5.8% surge over a four-session win streak, and rocketed 14% over the next two months.