VIX is short for the Chicago Board Options Exchange Volatility Index. It is a measure used to track volatility on the S&P 500 index, and is the most well-known volatility index on the markets.
A volatility index is a measure of a particular market’s likelihood of making sudden, unexpected price movements, or its relative instability. The VIX does this by aggregating the implied volatility on a set number of put and call options based on the S&P 500.
The implied volatility of these options is used to calculate a numerical figure for overall 30-day volatility of the S&P 500, which is in turn used as an indicator of general market sentiment. If the VIX gives a value of greater than 30 then the market is seen as volatile, while under 20 is believed to be calm.
