V-Lab
S&P GSCI Wheat Index GJR-GARCH Volatility Analysis
Volatility prediction for Monday, July 27th, 2026
1 Day
33.70%
decreased by 0.14%
1 Week
33.58%
decreased by 0.26%
1 Month
33.15%
decreased by 0.69%
Analysis last updated: Friday, July 24, 2026 at 11:12 PM UTC
News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
Jan 2, 1990 to Jul 24, 2026Model Insight
With persistence 0.991, volatility shocks have a half-life of 74 trading days (~0.3 years), close to a unit root, so long-run forecasts are highly sensitive to this estimate.
Inverse leverage: Positive returns increase volatility 82% more than negative returns
σ
GJR-GARCH Model
Tap to view equation
| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 0.0268 | 19.41*** |
α ARCH Response to squared shocks | 0.0592 | 25.27*** |
β GARCH Volatility persistence | 0.9448 | 663.46*** |
γ leverage Additional response to negative shocks | -0.0266 | -7.25*** |
Persistence:
0.991
Half-life:
74 days
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