Skip to main content
V-Lab
V-Lab

CBOE EFA ETF Volatility Index GAS-GARCH Student T Volatility Analysis

Volatility prediction for Wednesday, October 21st, 2026

1 Day

191.99%

decreased by 19.11%

1 Week

188.42%

decreased by 22.68%

1 Month

178.14%

decreased by 32.96%

Analysis last updated: Wednesday, October 21, 2026 at 01:49 PM UTC

Press Delete or Backspace to remove this series.
Date Range:

from

10/20/2024

to

10/20/2026

6M ·

1Y ·

2Y ·

5Y ·

10Y ·

All

graph of CBOE EFA ETF Volatility Index GAS-GARCH-T

News Impact Curve

How returns affect tomorrow's volatility

Volatility Forecast

How volatility evolves over time

Parameter Estimates

Jan 2, 2008 to Oct 16, 2026

Model Insight

Volatility shocks decay with a half-life of 12 trading days, meaning a shock loses half its impact after approximately 12 days. Returns follow a Student-t distribution with v = 3.83 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 12-day half-lifev = 3.83 · fat tails
ParamValuet-stat
ωlong-run97.8988
2.19**
αscore0.1279
6.91***
βpersistence0.9419
38.72***
νDF3.8334
3.22***

0.942

Persistence

12d

Half-life
𝑓

GAS-GARCH-T Model

Tap to view equation

ParameterValuet-statistic
ω

long-run

Long-run variance given a price move

97.8988
2.19**
α

score

Weight on the scaled score

0.1279
6.91***
β

persistence

Volatility persistence

0.9419
38.72***
ν

DF

Student-t tail thickness

3.8334
3.22***

Persistence:

0.942

Half-life:

12 days