VIX (CBOE Volatility Index)

The VIX (CBOE Volatility Index) measures the volatility in the market. When the VIX is low, it means that the market is less volatile, and if the VIX is spiking, it means that the volatility in the market is increasing.

The VIX is negatively correlated with the performance of the S&P 500 index, which means that the VIX spikes during periods of turbulence in the markets, such as market crashes. The VIX, also known as the fear index, spikes during periods of uncertainty in the markets.