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
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News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
Jan 2, 2008 to Oct 16, 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 = 3.83 degrees of freedom, capturing fatter tails than a normal distribution.
𝑓
GAS-GARCH-T Model
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Shock decay: Shocks decay with a 12-day half-lifev = 3.83 · fat tails
| Param | Value | t-stat |
|---|---|---|
| ωlong-run | 97.8988 | 2.19** |
| αscore | 0.1279 | 6.91*** |
| βpersistence | 0.9419 | 38.72*** |
| νDF | 3.8334 | 3.22*** |
0.942
Persistence12d
Half-life𝑓
GAS-GARCH-T Model
Tap to view equation
| Parameter | Value | t-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
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