V-Lab
State Street Utilities Select Sector SPDR ETF GAS-GARCH Student T Volatility Analysis
Volatility prediction for Monday, September 21st, 2026
1 Day
16.66%
increased by 1.08%
1 Week
16.72%
increased by 1.14%
1 Month
16.93%
increased by 1.35%
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 48 trading days, meaning a shock loses half its impact after approximately 48 days. Returns follow a Student-t distribution with v = 10.20 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 48-day half-lifev = 10.20 · fat tails
| Param | Value | t-stat |
|---|---|---|
| ωconst | 1.3756 | 2.89*** |
| αARCH | 0.0822 | 8.12*** |
| βGARCH | 0.9857 | 192.67*** |
| νDF | 10.2039 | 1.09 |
0.986
Persistence48d
Half-life𝑓
GAS-GARCH-T Model
Tap to view equation
| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 1.3756 | 2.89*** |
α ARCH Response to squared shocks | 0.0822 | 8.12*** |
β GARCH Volatility persistence | 0.9857 | 192.67*** |
ν DF Student-t tail thickness | 10.2039 | 1.09 |
Persistence:
0.986
Half-life:
48 days
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