Skip to main content
V-Lab
V-Lab

Russell 1000 Growth Index GAS-GARCH Student T Volatility Analysis

Volatility prediction for Friday, September 25th, 2026

1 Day

17.09%

decreased by 1.08%

1 Week

17.21%

decreased by 0.96%

1 Month

17.68%

decreased by 0.49%

Analysis last updated: Friday, September 25, 2026 at 08:55 AM UTC

Date Range:

from

to

6M ·

1Y ·

2Y ·

5Y ·

10Y ·

All

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 Sep 18, 2026

Model Insight

With persistence 0.994, volatility shocks have a half-life of 121 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 = 8.40 degrees of freedom, capturing fatter tails than a normal distribution.

𝑓

GAS-GARCH-T Model

Tap to view equation

High persistence: persistence 0.994, shock half-life ~121 daysv = 8.40 · fat tails
ParamValuet-stat
ωconst2.6309
1.10
αARCH0.0951
9.68***
βGARCH0.9943
185.85***
νDF8.4029
1.62

0.994

Persistence

121d

Half-life
𝑓

GAS-GARCH-T Model

Tap to view equation

ParameterValuet-statistic
ω

const

Unconditional variance weight

2.6309
1.10
α

ARCH

Response to squared shocks

0.0951
9.68***
β

GARCH

Volatility persistence

0.9943
185.85***
ν

DF

Student-t tail thickness

8.4029
1.62

Persistence:

0.994

Half-life:

121 days