Shares of F5 Networks, Inc. (NASDAQ:FFIV) reversed from all-time highs today, turning negative. The reversal forms a technical topping tail. Topping tails are extremely bearish signals, usually telling investors a strong reversal is about to take place. Based on chart analysis, the downside target on a short could be as low as $119.50. That would be an 18% drop from the current price. F5 Networks, Inc. is ripe for a short here and I have stepped in the trade.