V-Lab
Hevol Services Group Co Ltd Zero Slope Spline-GARCH Volatility Analysis
Volatility prediction for Thursday, August 20th, 2026
1 Day
82.61%
decreased by 3.62%
1 Week
93.08%
increased by 6.85%
1 Month
103.03%
increased by 16.80%
Analysis last updated: Thursday, August 20, 2026 at 06:47 PM UTC
News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
Jul 12, 2019 to Aug 14, 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
| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 1.4767 | 2.70*** |
α ARCH Response to squared shocks | 0.2206 | 4.76*** |
β GARCH Volatility persistence | 0.5254 | 6.08*** |
Spline Coefficients
K=10
| γ1 | 6.2234 | 1.64 |
| γ2 | -9.9636 | -1.56 |
| γ3 | 2.2312 | 0.46 |
| γ4 | 7.1641 | 2.11** |
| γ5 | -10.3030 | -4.95*** |
| γ6 | 8.3186 | 5.35*** |
| γ7 | -7.6610 | -5.06*** |
| γ8 | 7.5077 | 4.93*** |
| γ9 | -3.6519 | -1.64 |
| γ10 | -1.1567 | -0.53 |
Persistence:
0.746
Half-life:
2 days
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