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V-Lab

S&P GSCI Grains Spot Index GAS-GARCH Student T Volatility Analysis

Volatility prediction for Friday, July 17th, 2026

1 Day

22.17%

decreased by 0.48%

1 Week

22.14%

decreased by 0.51%

1 Month

22.03%

decreased by 0.62%

Analysis last updated: Thursday, July 16, 2026 at 11:03 PM UTC

Date Range:

from

to

6M ·

1Y ·

2Y ·

5Y ·

10Y ·

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graph of S&P GSCI Grains Spot Index GAS-GARCH-T

News Impact Curve

How returns affect tomorrow's volatility

Volatility Forecast

How volatility evolves over time

Parameter Estimates

Jan 2, 1990 to Jul 10, 2026

Model Insight

Volatility shocks decay with a half-life of 62 trading days, meaning a shock loses half its impact after approximately 62 days. Returns follow a Student-t distribution with v = 9.72 degrees of freedom, capturing fatter tails than a normal distribution.

𝑓

GAS-GARCH-T Model

Tap to view equation

ParameterValuet-statistic
ω

const

Unconditional variance weight

1.7098
13.25***
α

ARCH

Response to squared shocks

0.0534
34.90***
β

GARCH

Volatility persistence

0.9888
1,232.96***
ν

DF

Student-t tail thickness

9.7247
4.32***

Persistence:

0.989

Half-life:

62 days