State Street Utilities Select Sector SPDR ETF Zero Slope Spline-GARCH Volatility Analysis
Volatility prediction for Thursday, October 22nd, 2026
1 Day
17.76%
decreased by 0.73%
1 Week
17.86%
decreased by 0.63%
1 Month
18.19%
decreased by 0.30%
Analysis last updated: Wednesday, October 21, 2026 at 09:51 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
This model fits a time-varying baseline (a spline), so volatility mean-reverts toward a slowly-shifting long-run level rather than a constant. Short-run deviations decay with a half-life of 29 trading days.
τ
Zero Slope Spline-GARCH Model
Tap to view equation
Time-varying baseline: volatility reverts to a slowly-shifting spline trend
| Param | Value | t-stat |
|---|---|---|
| ωconst | 1.4364 | 9.96*** |
| αARCH | 0.0862 | 8.49*** |
| βGARCH | 0.8899 | 80.78*** |
Spline Coefficients
K=2
| γ1 | 0.0096 | 5.05*** |
| γ2 | -0.0118 | -4.83*** |
0.976
Persistence29d
Half-lifeτ
Zero Slope Spline-GARCH Model
Tap to view equation
| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 1.4364 | 9.96*** |
α ARCH Response to squared shocks | 0.0862 | 8.49*** |
β GARCH Volatility persistence | 0.8899 | 80.78*** |
Spline Coefficients
K=2
| γ1 | 0.0096 | 5.05*** |
| γ2 | -0.0118 | -4.83*** |
Persistence:
0.976
Half-life:
29 days
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