Market Insider

Meet poster child for momentum stock selloff

Markets' selloff jitters

If there's one thing traders have been watching to track the hot move into—and now the super fast move out of—momentum stocks, it's the IBB.

The iShares Nasdaq Biotechnology ETF has been the tip of the arrow when it comes to trading momentum. It peaked at 272.23 on Feb. 25 and has since lost nearly 18 percent. It now hovers precariously above its 200-day moving average and was down more than 4.3 percent at midday Thursday.

Selling in momentum resumed early Thursday and snowballed, taking the broader market lower with it, the day after dovish Fed minutes gave stocks their best day in more than a month.

The Nasdaq once more led the declines after a two-day reprieve. It was off 2 percent in afternoon trading, erasing Wednesday''s gains. The Dow was down 0.8 percent and the was off 1.3 percent. The small cap Russell 2000 was off 1.8 percent, and the S&P 400 midcap index was off 1.5 percent.