Though the markets are trading right around the flat line, Twitter, whose share price has nearly doubled so far this month, is leading to the downside today (-10% as I write this). Other social media stocks like Facebook, Pandora, LinkedIn, Yelp and Zillow are also seeing outsized selling.

This is notable because these stocks have, up to this point, led the broader market higher. Should they top out it may have broader implications for risk appetites, which have been insatiable lately.

Below is my full chartist of momentum stocks:

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