V-Lab
Hevol Services Group Co Ltd Zero Slope Spline-GARCH Volatility Analysis
Volatility prediction for Friday, September 18th, 2026
1 Day
139.72%
increased by 7.78%
1 Week
124.38%
decreased by 7.56%
1 Month
106.65%
decreased by 25.29%
Analysis last updated: Friday, September 18, 2026 at 07:20 PM UTC
News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
Jul 12, 2019 to Sep 17, 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 2 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 | 1.4606 | 2.71*** |
| αARCH | 0.2388 | 4.89*** |
| βGARCH | 0.4950 | 5.83*** |
Spline Coefficients
K=10
| γ1 | 6.1827 | 1.66* |
| γ2 | -10.0434 | -1.61 |
| γ3 | 2.6025 | 0.55 |
| γ4 | 6.6850 | 1.96* |
| γ5 | -9.9513 | -4.63*** |
| γ6 | 8.1315 | 5.11*** |
| γ7 | -7.6445 | -4.89*** |
| γ8 | 7.8514 | 5.21*** |
| γ9 | -4.3775 | -2.30** |
| γ10 | -0.5200 | -0.27 |
0.734
Persistence2d
Half-lifeτ
Zero Slope Spline-GARCH Model
Tap to view equation
| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 1.4606 | 2.71*** |
α ARCH Response to squared shocks | 0.2388 | 4.89*** |
β GARCH Volatility persistence | 0.4950 | 5.83*** |
Spline Coefficients
K=10
| γ1 | 6.1827 | 1.66* |
| γ2 | -10.0434 | -1.61 |
| γ3 | 2.6025 | 0.55 |
| γ4 | 6.6850 | 1.96* |
| γ5 | -9.9513 | -4.63*** |
| γ6 | 8.1315 | 5.11*** |
| γ7 | -7.6445 | -4.89*** |
| γ8 | 7.8514 | 5.21*** |
| γ9 | -4.3775 | -2.30** |
| γ10 | -0.5200 | -0.27 |
Persistence:
0.734
Half-life:
2 days
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