S&P GSCI Corn Index GAS-GARCH Student T Volatility Analysis
Volatility prediction for Tuesday, July 21st, 2026
1 Day
24.37%
decreased by 0.39%
1 Week
24.37%
decreased by 0.39%
1 Month
24.36%
decreased by 0.40%
Analysis last updated: Monday, July 20, 2026 at 11:08 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 0.990, volatility shocks have a half-life of 69 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 = 7.15 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 | 2.3274 | 8.02*** |
α ARCH Response to squared shocks | 0.0649 | 37.61*** |
β GARCH Volatility persistence | 0.9901 | 747.22*** |
ν DF Student-t tail thickness | 7.1482 | 7.53*** |
Persistence:
0.990
Half-life:
69 days
Other GAS-GARCH Student T Analyses on Commodities