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V-Lab

S&P GSCI Wheat Index AGARCH Volatility Analysis

Volatility prediction for Tuesday, July 21st, 2026

1 Day

31.67%

decreased by 0.86%

1 Week

31.59%

decreased by 0.94%

1 Month

31.29%

decreased by 1.24%

Analysis last updated: Monday, July 20, 2026 at 11:10 PM UTC

Date Range:

from

to

6M ·

1Y ·

2Y ·

5Y ·

10Y ·

All

graph of S&P GSCI Wheat Index AGARCH

News Impact Curve

How returns affect tomorrow's volatility

Volatility Forecast

How volatility evolves over time

Parameter Estimates

Jan 2, 1990 to Jul 17, 2026

Model Insight

The news-impact curve is shifted (γ = -0.47) so that positive returns raise next-day volatility more than negative returns of the same size. Volatility rises more after gains than after losses, the reverse of the usual leverage effect and rare among risky assets.

σ

AGARCH Model

Tap to view equation

ParameterValuet-statistic
ω

const

Unconditional variance weight

0.0197
12.44***
α

ARCH

Response to squared shocks

0.0470
36.41***
β

GARCH

Volatility persistence

0.9430
644.56***
γ

leverage

Additional response to negative shocks

-0.4664
-17.64***

Persistence:

0.990

Half-life:

69 days