The United States Financial Industry Regulatory Authority (FINRA) began looking into whether the index had been the victim of manipulation, following a letter sent to the SEC. That letter claimed that...

The United States Financial Industry Regulatory Authority (FINRA) began looking into whether the index had been the victim of manipulation, following a letter sent to the SEC. That letter claimed that the index can be maneuvered by activities that affect the options prices from which it is calculated via sophisticated algorithms, which can post quotes for S&P 500 options and move the spot value of the VIX, without necessarily completing an options trade.