State Street Materials Select Sector SPDR ETF GAS-GARCH Student T Volatility Analysis
Volatility prediction for Friday, October 23rd, 2026
1 Day
14.18%
decreased by 0.01%
1 Week
14.46%
increased by 0.27%
1 Month
15.47%
increased by 1.28%
Analysis last updated: Thursday, October 22, 2026 at 09:42 PM UTC
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News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
Dec 22, 1998 to Oct 16, 2026Model Insight
Volatility shocks decay with a half-life of 60 trading days, meaning a shock loses half its impact after approximately 60 days. Returns follow a Student-t distribution with v = 11.44 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 60-day half-lifev = 11.44 · fat tails
| Param | Value | t-stat |
|---|---|---|
| ωlong-run | 2.2323 | 2.67*** |
| αscore | 0.0828 | 8.76*** |
| βpersistence | 0.9885 | 204.36*** |
| νDF | 11.4352 | 1.03 |
0.989
Persistence60d
Half-life𝑓
GAS-GARCH-T Model
Tap to view equation
| Parameter | Value | t-statistic |
|---|---|---|
ω long-run Long-run variance given a price move | 2.2323 | 2.67*** |
α score Weight on the scaled score | 0.0828 | 8.76*** |
β persistence Volatility persistence | 0.9885 | 204.36*** |
ν DF Student-t tail thickness | 11.4352 | 1.03 |
Persistence:
0.989
Half-life:
60 days
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