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V-Lab

S&P GSCI Grains Spot Index GJR-GARCH Volatility Analysis

Volatility prediction for Friday, August 7th, 2026

1 Day

21.36%

decreased by 0.59%

1 Week

21.37%

decreased by 0.58%

1 Month

21.40%

decreased by 0.55%

Analysis last updated: Thursday, August 6, 2026 at 11:04 PM UTC

Date Range:

from

to

6M ·

1Y ·

2Y ·

5Y ·

10Y ·

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graph of S&P GSCI Grains Spot Index GJR-GARCH

News Impact Curve

How returns affect tomorrow's volatility

Volatility Forecast

How volatility evolves over time

Parameter Estimates

Jan 2, 1990 to Jul 31, 2026

Model Insight

With persistence 0.990, volatility shocks have a half-life of 72 trading days (~0.3 years), close to a unit root, so long-run forecasts are highly sensitive to this estimate.

Inverse leverage: Positive returns increase volatility 40% more than negative returns

σ

GJR-GARCH Model

Tap to view equation

ParameterValuet-statistic
ω

const

Unconditional variance weight

0.0182
21.63***
α

ARCH

Response to squared shocks

0.0660
24.40***
β

GARCH

Volatility persistence

0.9338
626.70***
γ

leverage

Additional response to negative shocks

-0.0189
-4.32***

Persistence:

0.990

Half-life:

72 days