Citrix Systems, Inc. (CTXS), the U.S.-based software company, is ready to break out any day now. The stock is trading in a common triangle pattern known as a descending triangle. This has a declining resistance line narrowing in on a horizontal support level.

This gives us clear levels to watch, and once a line is broken, a quick double-digit move is likely coming. Here's the descending triangle pattern for the stock.

Descending triangle pattern on the chart of Citrix Systems, Inc. (CTXS)

You can see that the stock is currently in the middle between these two key levels. With a triangle pattern, we can calculate the expected move by simply taking the height of the pattern and applying it to the breakout point. The height, from the start of the red resistance line to the green support level, is $17.50.

A breakout below the support level signals a 17% decline. Depending on where the upwards breakout takes place, we are still looking at a solid double-digit gain of more than 15%. Take a look:

Height of triangle pattern on the chart of Citrix Systems, Inc. (CTXS)

In sum, Citrix Systems stock is set to break out. The double-digit move could come in either direction. Most triangle patterns are continuation patterns, which is calling for a double-digit gain, but if it breaks below the green support level, a quick 17% drop is likely in store.