The VIX, or Volatility Index, is a real-time market index that represents the market's expectations for volatility over the coming 30 days. Often referred to as the "fear gauge" or "fear index," the VIX is calculated by the Chicago Board Options Exchange (CBOE) and is derived from the price inputs of the S&P 500 index options. It provides a measure of market risk and investors' sentiments, which can be useful for portfolio management and risk assessment.