Beta Blocker

I wish that I could fly
Into the sky
So very high
Just like a dragonfly
--Lenny Kravitz

MV profs frequently observe that traders are 'chasing beta.' Beta is a measure of the change in the price of a security compared to the change in the price of a index (such as the S&P 500 Index). When general markets increase, a high beta stock such as Google (GOOG) or Research In Motion (RIMM) tends to move up more than the general trend.

The downside is that, when markets move down, high beta stocks tend to go down more.

As such, you'll typically observe traders piling into beta when markets move higher, and shedding them during market declines.