V-Lab
CBOE S&P 500 Spot Volatility Index GAS-GARCH Student T Volatility Analysis
Volatility prediction for Monday, September 14th, 2026
1 Day
214.53%
increased by 34.70%
1 Week
216.45%
increased by 36.62%
1 Month
221.93%
increased by 42.10%
Analysis last updated: Monday, September 14, 2026 at 03:13 PM UTC
News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
Jan 3, 2006 to Sep 11, 2026Model Insight
Volatility shocks decay with a half-life of 13 trading days, meaning a shock loses half its impact after approximately 13 days. Returns follow a Student-t distribution with v = 5.63 degrees of freedom, capturing fatter tails than a normal distribution.
𝑓
GAS-GARCH-T Model
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Shock decay: Shocks decay with a 13-day half-lifev = 5.63 · fat tails
| Param | Value | t-stat |
|---|---|---|
| ωconst | 216.6463 | 2.51** |
| αARCH | 0.1197 | 5.20*** |
| βGARCH | 0.9491 | 45.02*** |
| νDF | 5.6261 | 1.62 |
0.949
Persistence13d
Half-life𝑓
GAS-GARCH-T Model
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| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 216.6463 | 2.51** |
α ARCH Response to squared shocks | 0.1197 | 5.20*** |
β GARCH Volatility persistence | 0.9491 | 45.02*** |
ν DF Student-t tail thickness | 5.6261 | 1.62 |
Persistence:
0.949
Half-life:
13 days
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