V-Lab
Woolworths Holdings Ltd/South Africa Zero Slope Spline-GARCH Volatility Analysis
Volatility prediction for Friday, September 11th, 2026
1 Day
31.33%
increased by 2.20%
1 Week
31.38%
increased by 2.25%
1 Month
31.53%
increased by 2.40%
Analysis last updated: Friday, September 11, 2026 at 09:11 PM UTC
News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
Nov 3, 1997 to Sep 4, 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 14 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 | 1.4982 | 11.24*** |
| αARCH | 0.0695 | 7.45*** |
| βGARCH | 0.8810 | 54.62*** |
Spline Coefficients
K=2
| γ1 | 0.0059 | 4.45*** |
| γ2 | -0.0067 | -4.01*** |
0.950
Persistence14d
Half-lifeτ
Zero Slope Spline-GARCH Model
Tap to view equation
| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 1.4982 | 11.24*** |
α ARCH Response to squared shocks | 0.0695 | 7.45*** |
β GARCH Volatility persistence | 0.8810 | 54.62*** |
Spline Coefficients
K=2
| γ1 | 0.0059 | 4.45*** |
| γ2 | -0.0067 | -4.01*** |
Persistence:
0.950
Half-life:
14 days
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