S&P GSCI Wheat Index GAS-GARCH Student T Volatility Analysis
Volatility prediction for Tuesday, July 21st, 2026
1 Day
29.45%
decreased by 0.42%
1 Week
29.39%
decreased by 0.48%
1 Month
29.19%
decreased by 0.68%
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
With persistence 0.991, volatility shocks have a half-life of 73 trading days (~0.3 years), close to a unit root, so long-run forecasts are highly sensitive to this estimate. Returns follow a Student-t distribution with v = 11.80 degrees of freedom, capturing fatter tails than a normal distribution.
𝑓
GAS-GARCH-T Model
Tap to view equation
| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 2.7723 | 14.33*** |
α ARCH Response to squared shocks | 0.0461 | 33.23*** |
β GARCH Volatility persistence | 0.9906 | 1,572.34*** |
ν DF Student-t tail thickness | 11.7984 | 3.19*** |
Persistence:
0.991
Half-life:
73 days
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