S&P GSCI Cotton Index Zero Slope Spline-GARCH Volatility Analysis
Volatility prediction for Thursday, October 22nd, 2026
1 Day
22.60%
decreased by 0.15%
1 Week
22.65%
decreased by 0.10%
1 Month
22.82%
increased by 0.07%
Analysis last updated: Wednesday, October 21, 2026 at 11:02 PM UTC
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News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
Jan 2, 1990 to Oct 16, 2026Model Insight
With persistence 0.993, volatility shocks have a half-life of 98 trading days (~0.4 years), close to a unit root, so long-run forecasts are highly sensitive to this estimate.
τ
Zero Slope Spline-GARCH Model
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High persistence: persistence 0.993, shock half-life ~98 days
| Param | Value | t-stat |
|---|---|---|
| ωconst | 0.9524 | 10.35*** |
| αARCH | 0.0432 | 9.70*** |
| βGARCH | 0.9497 | 186.73*** |
Spline Coefficients
K=1
| γ1 | -0.0001 | -0.69 |
0.993
Persistence98d
Half-lifeτ
Zero Slope Spline-GARCH Model
Tap to view equation
| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 0.9524 | 10.35*** |
α ARCH Response to squared shocks | 0.0432 | 9.70*** |
β GARCH Volatility persistence | 0.9497 | 186.73*** |
Spline Coefficients
K=1
| γ1 | -0.0001 | -0.69 |
Persistence:
0.993
Half-life:
98 days
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