V-Lab
S&P GSCI Spot Index Zero Slope Spline-GARCH Volatility Analysis
Volatility prediction for Tuesday, September 29th, 2026
1 Day
19.98%
decreased by 0.45%
1 Week
20.13%
decreased by 0.30%
1 Month
20.64%
increased by 0.21%
Analysis last updated: Monday, September 28, 2026 at 11:09 PM UTC
News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
Jan 2, 1990 to Sep 25, 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 41 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 | 0.7552 | 5.18*** |
| αARCH | 0.0707 | 7.56*** |
| βGARCH | 0.9124 | 92.21*** |
Spline Coefficients
K=4
| γ1 | 0.0202 | 2.87*** |
| γ2 | -0.0401 | -4.08*** |
| γ3 | 0.0307 | 5.05*** |
| γ4 | -0.0140 | -3.14*** |
0.983
Persistence41d
Half-lifeτ
Zero Slope Spline-GARCH Model
Tap to view equation
| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 0.7552 | 5.18*** |
α ARCH Response to squared shocks | 0.0707 | 7.56*** |
β GARCH Volatility persistence | 0.9124 | 92.21*** |
Spline Coefficients
K=4
| γ1 | 0.0202 | 2.87*** |
| γ2 | -0.0401 | -4.08*** |
| γ3 | 0.0307 | 5.05*** |
| γ4 | -0.0140 | -3.14*** |
Persistence:
0.983
Half-life:
41 days
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