V-Lab
S&P GSCI Cotton Index GJR-GARCH Volatility Analysis
Volatility prediction for Monday, September 21st, 2026
1 Day
25.13%
decreased by 0.24%
1 Week
25.13%
decreased by 0.24%
1 Month
25.14%
decreased by 0.23%
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 0.993, volatility shocks have a half-life of 105 trading days (~0.4 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 0.993, shock half-life ~105 days
| Param | Value | t-stat |
|---|---|---|
| ωconst | 0.0165 | 4.67*** |
| αARCH | 0.0461 | 5.44*** |
| βGARCH | 0.9501 | 188.77*** |
| γleverage | -0.0056 | -0.41 |
0.993
Persistence105d
Half-lifeσ
GJR-GARCH Model
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| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 0.0165 | 4.67*** |
α ARCH Response to squared shocks | 0.0461 | 5.44*** |
β GARCH Volatility persistence | 0.9501 | 188.77*** |
γ leverage Additional response to negative shocks | -0.0056 | -0.41 |
Persistence:
0.993
Half-life:
105 days
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