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S&P GSCI Grains Spot Index AGARCH Volatility Analysis

Volatility prediction for Monday, September 7th, 2026

1 Day

23.26%

decreased by 0.62%

1 Week

23.24%

decreased by 0.64%

1 Month

23.13%

decreased by 0.75%

Analysis last updated: Friday, September 4, 2026 at 11:31 PM UTC

Date Range:

from

to

6M ·

1Y ·

2Y ·

5Y ·

10Y ·

All

graph of S&P GSCI Grains Spot Index AGARCH

News Impact Curve

How returns affect tomorrow's volatility

Volatility Forecast

How volatility evolves over time

Parameter Estimates

Jan 2, 1990 to Sep 4, 2026

Model Insight

With persistence 0.990, volatility shocks have a half-life of 70 trading days (~0.3 years), close to a unit root, so long-run forecasts are highly sensitive to this estimate.

Asymmetry: positive returns raise volatility more

σ

AGARCH Model

Tap to view equation

High persistence: persistence 0.990, shock half-life ~70 daysAsymmetry: positive returns raise volatility more
ParamValuet-stat
ωconst0.0154
4.31***
αARCH0.0555
10.76***
βGARCH0.9347
162.16***
γleverage-0.2397
-2.98***

0.990

Persistence

70d

Half-life
σ

AGARCH Model

Tap to view equation

ParameterValuet-statistic
ω

const

Unconditional variance weight

0.0154
4.31***
α

ARCH

Response to squared shocks

0.0555
10.76***
β

GARCH

Volatility persistence

0.9347
162.16***
γ

leverage

Additional response to negative shocks

-0.2397
-2.98***

Persistence:

0.990

Half-life:

70 days