Cboe S&P 500 9-Day Volatility Index (VIX9D)
The Cboe S&P 500 9-Day Volatility Index (VIX9D) and the Cboe Volatility Index® (VIX®) both reflect investors' consensus view of expected stock market volatility. While the VIX measures expectations of 30-day future volatility, the VIX9D provides a market-based gauge of expectations of 9-day volatility, making it particularly responsive to changes in the S&P 500® Index. The VIX9D Index provides a market estimate of short-term expected (implied) volatility that is calculated by using real-time S&P 500® Index option bid/ask quotes. VIX9D uses nearby and second nearby options with at least 1 day left to expiration and then weights them to yield a constant, nine-day measure of the expected volatility of the S&P 500 Index.