V-Lab
State Street SPDR S&P Semiconductor ETF GAS-GARCH Student T Volatility Analysis
Volatility prediction for Monday, September 14th, 2026
1 Day
37.62%
increased by 1.49%
1 Week
37.47%
increased by 1.34%
1 Month
36.92%
increased by 0.79%
Analysis last updated: Saturday, September 12, 2026 at 12:06 AM UTC
News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
Feb 6, 2006 to Sep 11, 2026Model Insight
Volatility shocks decay with a half-life of 49 trading days, meaning a shock loses half its impact after approximately 49 days. Returns follow a Student-t distribution with v = 11.14 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 49-day half-lifev = 11.14 · fat tails
| Param | Value | t-stat |
|---|---|---|
| ωconst | 4.0109 | 2.69*** |
| αARCH | 0.0704 | 6.66*** |
| βGARCH | 0.9859 | 143.15*** |
| νDF | 11.1356 | 0.84 |
0.986
Persistence49d
Half-life𝑓
GAS-GARCH-T Model
Tap to view equation
| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 4.0109 | 2.69*** |
α ARCH Response to squared shocks | 0.0704 | 6.66*** |
β GARCH Volatility persistence | 0.9859 | 143.15*** |
ν DF Student-t tail thickness | 11.1356 | 0.84 |
Persistence:
0.986
Half-life:
49 days
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