V-Lab
State Street Materials Select Sector SPDR ETF GAS-GARCH Student T Volatility Analysis
Volatility prediction for Monday, September 21st, 2026
1 Day
17.09%
increased by 1.07%
1 Week
17.27%
increased by 1.25%
1 Month
17.92%
increased by 1.90%
Analysis last updated: Friday, September 18, 2026 at 11:24 PM UTC
News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
Dec 22, 1998 to Sep 18, 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 = 11.39 degrees of freedom, capturing fatter tails than a normal distribution.
𝑓
GAS-GARCH-T Model
Tap to view equation
Shock decay: Shocks decay with a 60-day half-lifev = 11.39 · fat tails
| Param | Value | t-stat |
|---|---|---|
| ωconst | 2.2426 | 2.64*** |
| αARCH | 0.0831 | 8.73*** |
| βGARCH | 0.9885 | 202.52*** |
| νDF | 11.3876 | 1.03 |
0.989
Persistence60d
Half-life𝑓
GAS-GARCH-T Model
Tap to view equation
| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 2.2426 | 2.64*** |
α ARCH Response to squared shocks | 0.0831 | 8.73*** |
β GARCH Volatility persistence | 0.9885 | 202.52*** |
ν DF Student-t tail thickness | 11.3876 | 1.03 |
Persistence:
0.989
Half-life:
60 days
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