V-Lab
S&P GSCI Agricultural Spot Index GAS-GARCH Student T Volatility Analysis
Volatility prediction for Monday, September 21st, 2026
1 Day
17.22%
1 Week
17.22%
1 Month
17.21%
Analysis last updated: Saturday, September 19, 2026 at 12:03 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 0.991, 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 = 10.18 degrees of freedom, capturing fatter tails than a normal distribution.
GAS-GARCH-T Model
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| Param | Value | t-stat |
|---|---|---|
| ωconst | 1.1685 | 2.82*** |
| αARCH | 0.0515 | 8.71*** |
| βGARCH | 0.9905 | 269.96*** |
| νDF | 10.1761 | 0.98 |
0.991
Persistence73d
Half-lifeGAS-GARCH-T Model
Tap to view equation
| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 1.1685 | 2.82*** |
α ARCH Response to squared shocks | 0.0515 | 8.71*** |
β GARCH Volatility persistence | 0.9905 | 269.96*** |
ν DF Student-t tail thickness | 10.1761 | 0.98 |
Persistence:
0.991
Half-life:
73 days
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