VIX (Volatility Index)

A real-time index calculated by the CBOE that measures the market's expectation of 30-day forward volatility, derived from S&P 500 option prices. Often called the "fear gauge," the VIX typically spikes during market selloffs and complacency-breaking events -- it hit an intraday high of 89.53 during the COVID crash in March 2020. Traders use VIX futures, options, and ETFs to hedge portfolios or speculate directly on volatility itself.