V-Lab
Hevol Services Group Co Ltd Zero Slope Spline-GARCH Volatility Analysis
Volatility prediction for Tuesday, September 8th, 2026
1 Day
83.10%
decreased by 0.23%
1 Week
95.29%
increased by 11.96%
1 Month
106.66%
increased by 23.33%
Analysis last updated: Tuesday, September 8, 2026 at 08:17 PM UTC
News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
Jul 12, 2019 to Aug 28, 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 | 1.4614 | 2.68*** |
| αARCH | 0.2240 | 4.79*** |
| βGARCH | 0.5213 | 6.07*** |
Spline Coefficients
K=10
| γ1 | 6.1483 | 1.65* |
| γ2 | -9.9737 | -1.59 |
| γ3 | 2.5447 | 0.54 |
| γ4 | 6.7066 | 1.96* |
| γ5 | -9.9451 | -4.62*** |
| γ6 | 8.1224 | 5.12*** |
| γ7 | -7.6428 | -4.90*** |
| γ8 | 7.8661 | 5.23*** |
| γ9 | -4.4098 | -2.27** |
| γ10 | -0.5323 | -0.27 |
0.745
Persistence2d
Half-lifeτ
Zero Slope Spline-GARCH Model
Tap to view equation
| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 1.4614 | 2.68*** |
α ARCH Response to squared shocks | 0.2240 | 4.79*** |
β GARCH Volatility persistence | 0.5213 | 6.07*** |
Spline Coefficients
K=10
| γ1 | 6.1483 | 1.65* |
| γ2 | -9.9737 | -1.59 |
| γ3 | 2.5447 | 0.54 |
| γ4 | 6.7066 | 1.96* |
| γ5 | -9.9451 | -4.62*** |
| γ6 | 8.1224 | 5.12*** |
| γ7 | -7.6428 | -4.90*** |
| γ8 | 7.8661 | 5.23*** |
| γ9 | -4.4098 | -2.27** |
| γ10 | -0.5323 | -0.27 |
Persistence:
0.745
Half-life:
2 days
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