Exhausted equity bulls look set to take a breather on Friday. Who can blame them after a week filled with dovish slants from central banks, notably the Fed, that produced a fresh S&P 500 record. But stay alert for one more distraction. Stock-index futures, stock-index options, single-stock futures, and stock options will all expire simultaneously today, an event known as quadruple witching, that happens every quarter on the third Friday of the last month. That can trigger volatility in the last hour of trading, but sometimes into the next week when it has coincided with an average loss of 1.09% for the Dow in 25 of ... (full story)