V-Lab
CBOE S&P 500 One-Year Volatility Index Zero Slope Spline-GARCH Volatility Analysis
Volatility prediction for Thursday, October 1st, 2026
1 Day
23.58%
increased by 0.09%
1 Week
27.58%
increased by 4.09%
1 Month
33.90%
increased by 10.41%
Analysis last updated: Thursday, October 1, 2026 at 11:32 AM UTC
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News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
Jan 3, 2007 to Sep 25, 2026Model Insight
This model fits a time-varying baseline (a spline), so volatility mean-reverts toward a slowly-shifting long-run level rather than a constant. Short-run deviations decay with a half-life of 5 trading days.
τ
Zero Slope Spline-GARCH Model
Tap to view equation
Time-varying baseline: volatility reverts to a slowly-shifting spline trend
| Param | Value | t-stat |
|---|---|---|
| ωconst | 1.2332 | 8.99*** |
| αARCH | 0.2440 | 7.49*** |
| βGARCH | 0.6295 | 16.69*** |
Spline Coefficients
K=1
| γ1 | 0.0011 | 1.91* |
0.873
Persistence5d
Half-lifeτ
Zero Slope Spline-GARCH Model
Tap to view equation
| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 1.2332 | 8.99*** |
α ARCH Response to squared shocks | 0.2440 | 7.49*** |
β GARCH Volatility persistence | 0.6295 | 16.69*** |
Spline Coefficients
K=1
| γ1 | 0.0011 | 1.91* |
Persistence:
0.873
Half-life:
5 days
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