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HSI Volatility Index GAS-GARCH Student T Volatility Analysis

Volatility prediction for Friday, September 18th, 2026

1 Day

56.63%

decreased by 2.86%

1 Week

60.68%

increased by 1.19%

1 Month

70.55%

increased by 11.06%

Analysis last updated: Friday, September 18, 2026 at 09:59 PM UTC

Date Range:

from

to

6M ·

1Y ·

2Y ·

5Y ·

10Y ·

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graph of HSI Volatility Index GAS-GARCH-T

News Impact Curve

How returns affect tomorrow's volatility

Volatility Forecast

How volatility evolves over time

Parameter Estimates

Jul 16, 2010 to Sep 10, 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 = 4.64 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 = 4.64 · fat tails
ParamValuet-stat
ωconst29.2374
1.80*
αARCH0.1092
4.23***
βGARCH0.9394
28.74***
νDF4.6358
1.40

0.939

Persistence

11d

Half-life
𝑓

GAS-GARCH-T Model

Tap to view equation

ParameterValuet-statistic
ω

const

Unconditional variance weight

29.2374
1.80*
α

ARCH

Response to squared shocks

0.1092
4.23***
β

GARCH

Volatility persistence

0.9394
28.74***
ν

DF

Student-t tail thickness

4.6358
1.40

Persistence:

0.939

Half-life:

11 days