V-Lab
CBOE S&P 500 Constituent Volatility Index Zero Slope Spline-GARCH Volatility Analysis
Volatility prediction for Wednesday, August 26th, 2026
1 Day
44.42%
decreased by 0.90%
1 Week
48.45%
increased by 3.13%
1 Month
55.13%
increased by 9.81%
Analysis last updated: Wednesday, August 26, 2026 at 11:33 AM UTC
News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
Jun 19, 2014 to Aug 21, 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
| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 0.8691 | 9.37*** |
α ARCH Response to squared shocks | 0.1427 | 5.36*** |
β GARCH Volatility persistence | 0.7255 | 17.38*** |
Spline Coefficients
K=2
| γ1 | -0.0241 | -2.51** |
| γ2 | 0.0327 | 2.72*** |
Persistence:
0.868
Half-life:
5 days
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