V-Lab
S&P GSCI Grains Spot Index Spline-GARCH Volatility Analysis
Volatility prediction for Wednesday, September 9th, 2026
1 Day
21.02%
decreased by 0.61%
1 Week
20.92%
decreased by 0.71%
1 Month
20.57%
decreased by 1.06%
Analysis last updated: Tuesday, September 8, 2026 at 11:31 PM UTC
News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
Jan 2, 1990 to Sep 8, 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 42 trading days.
τ
Spline-GARCH Model
Tap to view equation
Time-varying baseline: volatility reverts to a slowly-shifting spline trend
| Param | Value | t-stat |
|---|---|---|
| ωconst | 0.6873 | 11.04*** |
| αARCH | 0.0597 | 10.37*** |
| βGARCH | 0.9239 | 129.80*** |
Spline Coefficients
K=1
| γ1 | -0.0018 | -3.75*** |
0.984
Persistence42d
Half-lifeτ
Spline-GARCH Model
Tap to view equation
| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 0.6873 | 11.04*** |
α ARCH Response to squared shocks | 0.0597 | 10.37*** |
β GARCH Volatility persistence | 0.9239 | 129.80*** |
Spline Coefficients
K=1
| γ1 | -0.0018 | -3.75*** |
Persistence:
0.984
Half-life:
42 days
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