S&P GSCI Wheat Index AGARCH Volatility Analysis
Volatility prediction for Tuesday, July 21st, 2026
1 Day
31.67%
decreased by 0.86%
1 Week
31.59%
decreased by 0.94%
1 Month
31.29%
decreased by 1.24%
Analysis last updated: Monday, July 20, 2026 at 11:10 PM UTC
News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
Jan 2, 1990 to Jul 17, 2026Model Insight
The news-impact curve is shifted (γ = -0.47) so that positive returns raise next-day volatility more than negative returns of the same size. Volatility rises more after gains than after losses, the reverse of the usual leverage effect and rare among risky assets.
σ
AGARCH Model
Tap to view equation
| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 0.0197 | 12.44*** |
α ARCH Response to squared shocks | 0.0470 | 36.41*** |
β GARCH Volatility persistence | 0.9430 | 644.56*** |
γ leverage Additional response to negative shocks | -0.4664 | -17.64*** |
Persistence:
0.990
Half-life:
69 days
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