V-Lab
S&P 1000 Index Zero Slope Spline-GARCH Volatility Analysis
Volatility prediction for Tuesday, September 22nd, 2026
1 Day
12.62%
decreased by 0.36%
1 Week
13.08%
increased by 0.10%
1 Month
14.58%
increased by 1.60%
Analysis last updated: Monday, September 21, 2026 at 11:01 PM UTC
News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
Dec 29, 1994 to Sep 18, 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 39 trading days.
τ
Zero Slope Spline-GARCH Model
Tap to view equation
Time-varying baseline: volatility reverts to a slowly-shifting spline trend
| Param | Value | t-stat |
|---|---|---|
| ωconst | 0.7894 | 9.00*** |
| αARCH | 0.1062 | 10.43*** |
| βGARCH | 0.8762 | 84.65*** |
Spline Coefficients
K=1
| γ1 | -0.0005 | -2.85*** |
0.982
Persistence39d
Half-lifeτ
Zero Slope Spline-GARCH Model
Tap to view equation
| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 0.7894 | 9.00*** |
α ARCH Response to squared shocks | 0.1062 | 10.43*** |
β GARCH Volatility persistence | 0.8762 | 84.65*** |
Spline Coefficients
K=1
| γ1 | -0.0005 | -2.85*** |
Persistence:
0.982
Half-life:
39 days
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