V-Lab
CBOE Skew Index Zero Slope Spline-GARCH Volatility Analysis
Volatility prediction for Friday, August 21st, 2026
1 Day
38.28%
decreased by 1.99%
1 Week
44.26%
increased by 3.99%
1 Month
50.96%
increased by 10.69%
Analysis last updated: Friday, August 21, 2026 at 11:31 AM UTC
News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
Jan 2, 1990 to Aug 14, 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 3 trading days.
τ
Zero Slope Spline-GARCH Model
Tap to view equation
| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 2.8476 | 4.24*** |
α ARCH Response to squared shocks | 0.2656 | 11.00*** |
β GARCH Volatility persistence | 0.5272 | 14.91*** |
Spline Coefficients
K=10
| γ1 | 0.0950 | 2.10** |
| γ2 | -0.0512 | -0.85 |
| γ3 | -0.0837 | -1.96* |
| γ4 | 0.1281 | 2.87*** |
| γ5 | -0.2029 | -5.25*** |
| γ6 | 0.2104 | 5.67*** |
| γ7 | -0.1275 | -3.80*** |
| γ8 | -0.0243 | -0.76 |
| γ9 | 0.1343 | 4.16*** |
| γ10 | -0.1125 | -4.73*** |
Persistence:
0.793
Half-life:
3 days
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