VIX

The VIX, or Chicago Board Options Exchange's CBOE Volatility Index, is a popular measure of the stock market's expectation of volatility, specifically derived from S&P 500 index options. It is calculated and disseminated in real-time by the CBOE.

The VIX originated from the financial economics research of Menachem Brenner and Dan Galai, who proposed the creation of a series of volatility indices, starting with an index on stock market volatility. In 1992, the CBOE hired consultant Bob Whaley to calculate values for stock market volatility based on this theoretical work.

The VIX index formulation provides a measure of market volatility on which expectations of further stock market volatility in the next 30 days are based. This makes it a crucial tool for investors and traders to gauge market sentiment and potential risk.