What Makes the VIX Tick?

We study one-minute changes in VIX, an index of ex ante S&P 500 volatility, using measures   of   public  information,   trading   conditions,   and   investor   sentiment. Autocorrelation and leverage or volatility feedback have the most explanatory power. Some evidence on short term interest rates and liquidity suggests expected ineffective Fed   monetary  easing.     Two  surprises  are,  first,  reversals  in  VIX  reactions  to macroeconomic news, short term interest rates, and credit default spreads, and, second, VIX and gold do not reflect hedging demand or fear similarly. Investor sentiment seems of secondary importance to VIX.