V-Lab
CBOE S&P 500 Left Tail Volatility Index Zero Slope Spline-GARCH Volatility Analysis
Volatility prediction for Friday, August 14th, 2026
1 Day
146.45%
decreased by 4.05%
1 Week
164.69%
increased by 14.19%
1 Month
188.74%
increased by 38.24%
Analysis last updated: Friday, August 14, 2026 at 11:30 AM UTC
News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
Jan 3, 2006 to Aug 7, 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 4 trading days.
τ
Zero Slope Spline-GARCH Model
Tap to view equation
| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 0.8529 | 4.34*** |
α ARCH Response to squared shocks | 0.1991 | 7.74*** |
β GARCH Volatility persistence | 0.6266 | 13.98*** |
Spline Coefficients
K=9
| γ1 | -0.3286 | -2.29** |
| γ2 | 0.4448 | 2.29** |
| γ3 | -0.3448 | -2.84*** |
| γ4 | 0.4836 | 4.20*** |
| γ5 | -0.3798 | -3.20*** |
| γ6 | 0.2327 | 1.74* |
| γ7 | -0.1894 | -1.48 |
| γ8 | 0.1272 | 1.19 |
| γ9 | -0.0651 | -0.87 |
Persistence:
0.826
Half-life:
4 days
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