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Russell 1000 Growth Index GAS-GARCH Student T Volatility Analysis

Volatility prediction for Monday, August 17th, 2026

1 Day

30.69%

increased by 6.45%

1 Week

30.65%

increased by 6.41%

1 Month

30.50%

increased by 6.26%

Analysis last updated: Saturday, August 15, 2026 at 12:08 AM UTC

Date Range:

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to

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1Y ·

2Y ·

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10Y ·

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graph of Russell 1000 Growth Index GAS-GARCH-T

News Impact Curve

How returns affect tomorrow's volatility

Volatility Forecast

How volatility evolves over time

Parameter Estimates

May 12, 2000 to Aug 14, 2026

Model Insight

With persistence 0.995, volatility shocks have a half-life of 131 trading days (~0.5 years), close to a unit root, so long-run forecasts are highly sensitive to this estimate. Returns follow a Student-t distribution with v = 8.29 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

2.8142
4.33***
α

ARCH

Response to squared shocks

0.0953
40.19***
β

GARCH

Volatility persistence

0.9947
801.54***
ν

DF

Student-t tail thickness

8.2916
6.76***

Persistence:

0.995

Half-life:

131 days