V-Lab
Russell 1000 Growth Index Zero Slope Spline-GARCH Volatility Analysis
Volatility prediction for Monday, July 27th, 2026
1 Day
22.63%
increased by 0.19%
1 Week
22.69%
increased by 0.25%
1 Month
22.89%
increased by 0.45%
Analysis last updated: Saturday, July 25, 2026 at 12:05 AM UTC
News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
May 12, 2000 to Jul 24, 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 25 trading days.
τ
Zero Slope Spline-GARCH Model
Tap to view equation
| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 2.0393 | 7.78*** |
α ARCH Response to squared shocks | 0.1059 | 9.79*** |
β GARCH Volatility persistence | 0.8667 | 69.76*** |
Spline Coefficients
K=4
| γ1 | 0.0555 | 5.38*** |
| γ2 | -0.0761 | -4.55*** |
| γ3 | 0.0432 | 3.01*** |
| γ4 | -0.0349 | -3.46*** |
Persistence:
0.973
Half-life:
25 days
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