The VIX Index, also known as the Volatility Index, measures market expectations of future volatility based on options prices of the S&P 500. It reflects investor sentiment and is often referred to as the "fear gauge," indicating how much volatility traders expect in the near term. A higher VIX value suggests increased uncertainty or risk in the market, while a lower value indicates a more stable environment. Investors and traders use the VIX to make informed decisions about their portfolios, hedging strategies, and overall market outlook.