what are some price abnormalities seen on triple witching dates 
an interesting phenomenon is that often the price of a security may artificially tend toward a strike price with large open interest as gamma hedging takes place gamma hedging works to minimize the risk associated with changes in delta providing a more stable options portfolio changes in delta in turn are most simply defined as the change in an option s price sensitivity to any changes in the underlying asset s price the gamma hedging can lead the price to pin the strike at expiration pinning the strike when an underlying security s market price closes very near the strike price of heavily traded options can bring pin risk for options traders uncertain whether to exercise the long options that have expired in the money or are very close to it this is because they are also unsure how many of their similar short positions will be assigned the bottom linetriple witching refers to the third friday of march june september and december when three kinds of securities stock market index futures stock market index options and stock options expire on the same day derivatives traders pay close attention on these dates given the potential for increased volume and volatility in the markets 