CBOE S&P 500 9-Day Volatility Index GAS-GARCH Student T Volatility Analysis
Volatility prediction for Wednesday, July 15th, 2026
1 Day
237.41%
decreased by 13.05%
1 Week
223.88%
decreased by 26.58%
1 Month
206.74%
decreased by 43.72%
Analysis last updated: Wednesday, July 15, 2026 at 11:30 AM UTC
News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
Jan 3, 2011 to Jul 10, 2026Model Insight
Volatility shocks decay with a half-life of 3 trading days, meaning a shock loses half its impact after approximately 3 days. Returns follow a Student-t distribution with v = 5.18 degrees of freedom, capturing fatter tails than a normal distribution.
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GAS-GARCH-T Model
Tap to view equation
| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 155.3730 | 19.18*** |
α ARCH Response to squared shocks | 0.1140 | 10.69*** |
β GARCH Volatility persistence | 0.7726 | 50.65*** |
ν DF Student-t tail thickness | 5.1767 | 3.21*** |
Persistence:
0.773
Half-life:
3 days
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