State Street Technology Select Sector SPDR ETF GAS-GARCH Student T Volatility Analysis
Volatility prediction for Friday, October 23rd, 2026
1 Day
27.76%
1 Week
27.77%
1 Month
27.84%
Analysis last updated: Thursday, October 22, 2026 at 09:42 PM UTC
News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
Dec 22, 1998 to Oct 16, 2026Model Insight
With persistence 0.995, volatility shocks have a half-life of 132 trading days (~0.5 years), close to a unit root, so long-run forecasts are highly sensitive to this estimate. Returns follow a Student-t distribution with v = 8.69 degrees of freedom, capturing fatter tails than a normal distribution.
GAS-GARCH-T Model
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| Param | Value | t-stat |
|---|---|---|
| ωlong-run | 3.4335 | 1.40 |
| αscore | 0.0861 | 11.82*** |
| βpersistence | 0.9948 | 250.51*** |
| νDF | 8.6932 | 1.83* |
0.995
Persistence132d
Half-lifeGAS-GARCH-T Model
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| Parameter | Value | t-statistic |
|---|---|---|
ω long-run Long-run variance given a price move | 3.4335 | 1.40 |
α score Weight on the scaled score | 0.0861 | 11.82*** |
β persistence Volatility persistence | 0.9948 | 250.51*** |
ν DF Student-t tail thickness | 8.6932 | 1.83* |
Persistence:
0.995
Half-life:
132 days
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