V-Lab
SMI Volatility Index Zero Slope Spline-GARCH Volatility Analysis
Volatility prediction for Friday, September 25th, 2026
1 Day
68.26%
decreased by 0.31%
1 Week
71.23%
increased by 2.66%
1 Month
75.72%
increased by 7.15%
Analysis last updated: Friday, September 25, 2026 at 09:00 PM UTC
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News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
Jan 4, 1999 to Sep 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 4 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 | 0.7603 | 8.84*** |
| αARCH | 0.1475 | 7.53*** |
| βGARCH | 0.6904 | 19.29*** |
Spline Coefficients
K=6
| γ1 | -0.0265 | -1.42 |
| γ2 | 0.0475 | 1.73* |
| γ3 | -0.0309 | -1.63 |
| γ4 | 0.0175 | 0.94 |
| γ5 | -0.0320 | -1.80* |
| γ6 | 0.0393 | 3.15*** |
0.838
Persistence4d
Half-lifeτ
Zero Slope Spline-GARCH Model
Tap to view equation
| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 0.7603 | 8.84*** |
α ARCH Response to squared shocks | 0.1475 | 7.53*** |
β GARCH Volatility persistence | 0.6904 | 19.29*** |
Spline Coefficients
K=6
| γ1 | -0.0265 | -1.42 |
| γ2 | 0.0475 | 1.73* |
| γ3 | -0.0309 | -1.63 |
| γ4 | 0.0175 | 0.94 |
| γ5 | -0.0320 | -1.80* |
| γ6 | 0.0393 | 3.15*** |
Persistence:
0.838
Half-life:
4 days
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