V-Lab
CBOE S&P 500 Left Tail Volatility Index Zero Slope Spline-GARCH Volatility Analysis
Volatility prediction for Friday, July 24th, 2026
1 Day
182.64%
increased by 7.10%
1 Week
189.37%
increased by 13.83%
1 Month
199.07%
increased by 23.53%
Analysis last updated: Friday, July 24, 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 Jul 17, 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 | 0.8530 | 4.33*** |
α ARCH Response to squared shocks | 0.1992 | 7.72*** |
β GARCH Volatility persistence | 0.6272 | 14.01*** |
Spline Coefficients
K=9
| γ1 | -0.3292 | -2.28** |
| γ2 | 0.4460 | 2.28** |
| γ3 | -0.3466 | -2.84*** |
| γ4 | 0.4849 | 4.19*** |
| γ5 | -0.3790 | -3.16*** |
| γ6 | 0.2304 | 1.70* |
| γ7 | -0.1857 | -1.44 |
| γ8 | 0.1223 | 1.13 |
| γ9 | -0.0613 | -0.80 |
Persistence:
0.826
Half-life:
4 days
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