During a market downturn the VIX is a commonly referenced indicator. The value of the VIX is derived from the price of out-of-the-money S&P 500 (SPX) put options and will increase as SPX declines. Given this behavior in the VIX, it can be used as a valuable trading tool on its own and in combination with other indexes or indicators . For example, one of the most common strategies is buying put options on the SPX when prices begin to top or decline. In other words, the VIX can be used for a simple equity market hedging strategy . This buying of SPX put options will cause the implied volatility to rise, resulting in higher premiums for the options. Since the VIX measures implied volatility of SPX index options, it will move inversely with the SPX. That is, as prices fall there is more put option buying which results in higher VIX levels. Not only does VIX increase as SPX declines, but it also has a tendency to increase more quickly the faster and farther the S...
Price-based perspective on market behavior