Volatility Index (VIX) is a financial metric that measures the market's expectation of stock market volatility over the next 30-day period. It is sometimes referred to as the "Fear Index" or the "Fear Gauge". The VIX is calculated and published by the Chicago Board Options Exchange (CBOE) and is based on the prices of options contracts on the S&P 500 stock index. A high VIX value indicates that the market is expecting high volatility in the near term, which may be due to uncertainty or fear in the market. A low VIX value, on the other hand, suggests that the market is expecting low volatility and a more stable market environment.