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
News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
Jan 2, 2008 to Aug 14, 2026Model 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
| Parameter | Value | t-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
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