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Nikkei Stock Average Volatility Index GAS-GARCH Student T Volatility Analysis

Volatility prediction for Monday, September 14th, 2026

1 Day

142.74%

decreased by 16.74%

1 Week

138.55%

decreased by 20.93%

1 Month

126.41%

decreased by 33.07%

Analysis last updated: Friday, September 18, 2026 at 10:00 PM UTC

Date Range:

from

to

6M ·

1Y ·

2Y ·

5Y ·

10Y ·

All

graph of Nikkei Stock Average Volatility Index GAS-GARCH-T

News Impact Curve

How returns affect tomorrow's volatility

Volatility Forecast

How volatility evolves over time

Parameter Estimates

Jan 3, 1990 to Sep 11, 2026

Model Insight

Volatility shocks decay with a half-life of 11 trading days, meaning a shock loses half its impact after approximately 11 days. Returns follow a Student-t distribution with v = 4.59 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 11-day half-lifev = 4.59 · fat tails
ParamValuet-stat
ωconst39.9747
3.13***
αARCH0.1186
7.35***
βGARCH0.9392
50.30***
νDF4.5890
2.62***

0.939

Persistence

11d

Half-life
𝑓

GAS-GARCH-T Model

Tap to view equation

ParameterValuet-statistic
ω

const

Unconditional variance weight

39.9747
3.13***
α

ARCH

Response to squared shocks

0.1186
7.35***
β

GARCH

Volatility persistence

0.9392
50.30***
ν

DF

Student-t tail thickness

4.5890
2.62***

Persistence:

0.939

Half-life:

11 days