Momentum Stocks Are Getting Crushed Again

In trading action eerily reminiscent of that seen in March and April, momentum stocks like FireEye, Zulily, Yelp, and Twitter are taking a beating today.

FireEye is down almost 8%, while Zulily is down 8.3%, Yelp is down 7.5% and Twitter is down 7.3%.

The Nasdaq, which houses many of the internet-related stocks, is down 1.3%, or 58 points. On a percentage basis, the Nasdaq's loss is more than double the decline of the S&P 500 and the Dow, which are lower by about 0.6% each.

On Twitter, Bespoke Investment Group said, "Momentum names acting like they did in March and April last two days. Definitely going to hit sentiment hard."

CNBC's Carl Quintanilla also said that this is the worst 2-day decline for the Nasdaq since May 6-7.

Over the last 18 month bull market, the Nasdaq and the small-cap Russell 2000 have outperformed the S&P 500 and Dow.

The indices and stocks that lead on the way up, however, often lead on the way down.