V-Lab
Kelly Services Inc Zero Slope Spline-GARCH Volatility Analysis
Volatility prediction for Monday, September 14th, 2026
1 Day
34.93%
decreased by 1.84%
1 Week
36.05%
decreased by 0.72%
1 Month
37.69%
increased by 0.92%
Analysis last updated: Friday, September 11, 2026 at 11:04 PM UTC
News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
Jan 2, 1990 to Sep 11, 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 4 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 | 0.6305 | 9.20*** |
| αARCH | 0.1175 | 6.36*** |
| βGARCH | 0.7099 | 17.51*** |
Spline Coefficients
K=10
| γ1 | -0.0658 | -1.79* |
| γ2 | 0.1112 | 1.96** |
| γ3 | -0.0865 | -2.04** |
| γ4 | 0.0134 | 0.36 |
| γ5 | 0.1547 | 4.49*** |
| γ6 | -0.2934 | -9.02*** |
| γ7 | 0.2555 | 6.39*** |
| γ8 | -0.0689 | -1.29 |
| γ9 | -0.0651 | -1.17 |
| γ10 | 0.0593 | 1.46 |
0.827
Persistence4d
Half-lifeτ
Zero Slope Spline-GARCH Model
Tap to view equation
| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 0.6305 | 9.20*** |
α ARCH Response to squared shocks | 0.1175 | 6.36*** |
β GARCH Volatility persistence | 0.7099 | 17.51*** |
Spline Coefficients
K=10
| γ1 | -0.0658 | -1.79* |
| γ2 | 0.1112 | 1.96** |
| γ3 | -0.0865 | -2.04** |
| γ4 | 0.0134 | 0.36 |
| γ5 | 0.1547 | 4.49*** |
| γ6 | -0.2934 | -9.02*** |
| γ7 | 0.2555 | 6.39*** |
| γ8 | -0.0689 | -1.29 |
| γ9 | -0.0651 | -1.17 |
| γ10 | 0.0593 | 1.46 |
Persistence:
0.827
Half-life:
4 days
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