after a huge run in 2010 FFIV this year has been trading in a wide downward trendm which the stock is again trading at the top-end of today. see the weekly chart below. so from this point of view the simplistic approach would be to short some FFIV for a mean-reversion trade.
on the daily chart we also note the 200 sma (red line) coming into play as potential resistance here. looks like a decent short-side opportunity here with clear stops above the 200 sma.