Quadruple witching: Expect increased volatility By: CNBC.com News December 19, 2013 at 15:49 PM EST The increase in volatility and volume that comes along with quadruple witching on Friday will come with the S&P 500's quarterly rebalancing. Read More >> Related Stocks: Abercrombie & Fitch Company Amtd Idea Group Facebook Mohawk Industries Sentinelone Inc Cl A