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V-Lab

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

Volatility prediction for Friday, August 21st, 2026

1 Day

109.47%

decreased by 11.60%

1 Week

115.59%

decreased by 5.48%

1 Month

131.11%

increased by 10.04%

Analysis last updated: Friday, August 21, 2026 at 11:35 AM UTC

Date Range:

from

to

6M ·

1Y ·

2Y ·

5Y ·

10Y ·

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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 Aug 14, 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 = 3.81 degrees of freedom, capturing fatter tails than a normal distribution.

𝑓

GAS-GARCH-T Model

Tap to view equation

ParameterValuet-statistic
ω

const

Unconditional variance weight

97.8649
8.63***
α

ARCH

Response to squared shocks

0.1266
27.55***
β

GARCH

Volatility persistence

0.9425
153.60***
ν

DF

Student-t tail thickness

3.8086
12.92***

Persistence:

0.942

Half-life:

12 days