Increased Market Volatility Coming

The index measures the daily performance of a portfolio of long positions in first and second month VIX futures contracts. This theoretical portfolio is rolled each day to maintain a consistent time to maturity of the futures contracts. The index is calculated daily at 4:00 p.m. (Eastern time) and at a value calculated from the average price for the futures contracts between 3:45 p.m. (Eastern time) and 4:00 p.m. (Eastern time).

Its that time of the year.