One week after Friday the 13th, a far more important for the market Friday has arrived: quad-witching day, when once every quarter we get the simultaneous expiration of contracts for index futures, index options, stock options, and single stock futures, and when increased volatility and an explosion in volumes usually follow. As such, these days are entirely at the mercy of dealer and trader positioning, and as Charlie McElligott pointed out yesterday, as of this moment the S&P is “shackled” by a “Long Gamma” death-grip, with some $8.3BN in expiration at the 3,000 strike, which will ensure that the S&P gravitates around 3,000 for most of the day.