what are some price abnormalities observed on quadruple witching 
one interesting quirk is that the price of a security may artificially tend toward a strike price with large open interest as gamma hedging takes place a process known as pinning the strike pinning a strike imposes pin risk for options traders where they become uncertain whether or not options with strike prices near the market price will finish in the money and be exercised the bottom lineduring the last hour of trading on the third friday of march june september and december called the quadruple witching hour market activity can increase as traders adjust positions and rollover contracts investors should know this at a minimum to understand the reasons for increased trading at those times and plan accordingly 