In February 2006 the Chicago Board Options Exchange (CBOE) listed options on its S&P 500 volatility index (VIX). The VIX tracks the implied volatility (IV) of selected S&P 500 options and measures the market’s volatility forecast over the next 30 days.

However, the VIX doesn’t behave like a standard stock index or futures contract, and its options are also somewhat counterintuitive.