V-Lab
Dow Jones South Africa Index Zero Slope Spline-GARCH Volatility Analysis
Volatility prediction for Friday, September 11th, 2026
1 Day
16.55%
increased by 0.05%
1 Week
16.68%
increased by 0.18%
1 Month
17.11%
increased by 0.61%
Analysis last updated: Saturday, September 12, 2026 at 12:50 AM UTC
News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
Jan 1, 1992 to Sep 10, 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 34 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 | 0.8882 | 9.62*** |
| αARCH | 0.0867 | 9.31*** |
| βGARCH | 0.8934 | 81.01*** |
Spline Coefficients
K=1
| γ1 | -0.0002 | -1.77* |
0.980
Persistence34d
Half-lifeτ
Zero Slope Spline-GARCH Model
Tap to view equation
| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 0.8882 | 9.62*** |
α ARCH Response to squared shocks | 0.0867 | 9.31*** |
β GARCH Volatility persistence | 0.8934 | 81.01*** |
Spline Coefficients
K=1
| γ1 | -0.0002 | -1.77* |
Persistence:
0.980
Half-life:
34 days
Other Dow Jones South Africa Index Analyses
Other Zero Slope Spline-GARCH Analyses on Equity Indices