V-Lab
S&P GSCI Agricultural Spot Index AGARCH Volatility Analysis
Volatility prediction for Tuesday, September 29th, 2026
1 Day
16.00%
decreased by 0.10%
1 Week
16.04%
decreased by 0.06%
1 Month
16.19%
increased by 0.09%
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
With persistence 0.990, volatility shocks have a half-life of 70 trading days (~0.3 years), close to a unit root, so long-run forecasts are highly sensitive to this estimate.
σ
AGARCH Model
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High persistence: persistence 0.990, shock half-life ~70 days
| Param | Value | t-stat |
|---|---|---|
| ωconst | 0.0121 | 4.70*** |
| αARCH | 0.0577 | 11.01*** |
| βGARCH | 0.9325 | 153.67*** |
| γleverage | -0.0805 | -1.36 |
0.990
Persistence70d
Half-lifeσ
AGARCH Model
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| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 0.0121 | 4.70*** |
α ARCH Response to squared shocks | 0.0577 | 11.01*** |
β GARCH Volatility persistence | 0.9325 | 153.67*** |
γ leverage Additional response to negative shocks | -0.0805 | -1.36 |
Persistence:
0.990
Half-life:
70 days
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