What do shareholders in Acuity Brands (AYI -0.54%), Synnex Corp. (SNX 0.12%), and The Greenbrier Companies (GBX -0.43%) have in common? On the face of it, not much: the first is a lighting specialist, the second a technology distributor, and the last a manufacturer of railcars.

But next week, shareholders in all three of these companies will need to prepare for extreme volatility. That's because all three have a large numbers of shares sold short, and they are all scheduled to report earnings. Last time I identified such companies with these characteristics, they moved an average of 10% following their earnings releases.

Instead of trying to time the market based on this information, I think it's much wiser for existing shareholders to simply prepare mentally for the volatility. Instead of focusing on short-term moves, check out the slideshow below to see what you should really be focusing on.