V-Lab
S&P GSCI Cocoa Index GJR-GARCH Volatility Analysis
Volatility prediction for Monday, September 21st, 2026
1 Day
57.11%
increased by 2.70%
1 Week
57.00%
increased by 2.59%
1 Month
56.55%
increased by 2.14%
Analysis last updated: Saturday, September 19, 2026 at 12:02 AM UTC
News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
Jan 2, 1990 to Sep 18, 2026Model Insight
With persistence 0.997, volatility shocks have a half-life of 231 trading days (~0.9 years), close to a unit root, so long-run forecasts are highly sensitive to this estimate.
σ
GJR-GARCH Model
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High persistence: persistence 0.997, shock half-life ~231 days
| Param | Value | t-stat |
|---|---|---|
| ωconst | 0.0132 | 2.62*** |
| αARCH | 0.0405 | 4.87*** |
| βGARCH | 0.9643 | 204.08*** |
| γleverage | -0.0157 | -1.44 |
0.997
Persistence231d
Half-lifeσ
GJR-GARCH Model
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| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 0.0132 | 2.62*** |
α ARCH Response to squared shocks | 0.0405 | 4.87*** |
β GARCH Volatility persistence | 0.9643 | 204.08*** |
γ leverage Additional response to negative shocks | -0.0157 | -1.44 |
Persistence:
0.997
Half-life:
231 days
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