Skip to main content
V-Lab
V-Lab

S&P 1000 Index GAS-GARCH Student T Volatility Analysis

Volatility prediction for Tuesday, September 22nd, 2026

1 Day

12.22%

decreased by 0.44%

1 Week

12.49%

decreased by 0.17%

1 Month

13.42%

increased by 0.76%

Analysis last updated: Monday, September 21, 2026 at 11:01 PM UTC

Date Range:

from

to

6M ·

1Y ·

2Y ·

5Y ·

10Y ·

All

graph of S&P 1000 Index GAS-GARCH-T

News Impact Curve

How returns affect tomorrow's volatility

Volatility Forecast

How volatility evolves over time

Parameter Estimates

Dec 29, 1994 to Sep 18, 2026

Model Insight

Volatility shocks decay with a half-life of 46 trading days, meaning a shock loses half its impact after approximately 46 days. Returns follow a Student-t distribution with v = 12.24 degrees of freedom, capturing fatter tails than a normal distribution.

𝑓

GAS-GARCH-T Model

Tap to view equation

Shock decay: Shocks decay with a 46-day half-lifev = 12.24 · fat tails
ParamValuet-stat
ωconst1.4958
3.10***
αARCH0.0915
8.50***
βGARCH0.9851
173.28***
νDF12.2359
0.94

0.985

Persistence

46d

Half-life
𝑓

GAS-GARCH-T Model

Tap to view equation

ParameterValuet-statistic
ω

const

Unconditional variance weight

1.4958
3.10***
α

ARCH

Response to squared shocks

0.0915
8.50***
β

GARCH

Volatility persistence

0.9851
173.28***
ν

DF

Student-t tail thickness

12.2359
0.94

Persistence:

0.985

Half-life:

46 days