KLA-Tencor Corp (NASDAQ:KLAC) jumped higher in early trading, only to give it all up by the market close. This reversal took place at all-time highs, forming a technical analysis based topped tail. Topping tails are extremely bearish reversal signals. This likely alerts investors to a major reversal taking place in KLA-Tencor and significant downside in the coming days. Investors should be shorting, buying puts or in the very least selling long positions.