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V-Lab

JSE Securities South African Volatility Index Zero Slope Spline-GARCH Volatility Analysis

Volatility prediction for Friday, September 11th, 2026

1 Day

84.00%

decreased by 0.70%

1 Week

91.34%

increased by 6.64%

1 Month

100.28%

increased by 15.58%

Analysis last updated: Saturday, September 12, 2026 at 12:48 AM UTC

Date Range:

from

to

6M ·

1Y ·

2Y ·

5Y ·

10Y ·

All

graph of JSE Securities South African Volatility Index S0GARCH

News Impact Curve

How returns affect tomorrow's volatility

Volatility Forecast

How volatility evolves over time

Parameter Estimates

Feb 1, 2007 to Sep 10, 2026

Model 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 3 trading days.

τ

Zero Slope Spline-GARCH Model

Tap to view equation

Time-varying baseline: volatility reverts to a slowly-shifting spline trend
ParamValuet-stat
ωconst0.6759
4.67***
αARCH0.1350
4.45***
βGARCH0.6645
10.88***
γi Spline Coefficients
K=9
γ10.0094
0.06
γ2-0.1222
-0.55
γ30.3495
2.12**
γ4-0.5057
-2.28**
γ50.4145
1.73*
γ6-0.0068
-0.03
γ7-0.4969
-2.76***
γ80.7083
4.10***
γ9-0.5085
-4.04***

0.799

Persistence

3d

Half-life
τ

Zero Slope Spline-GARCH Model

Tap to view equation

ParameterValuet-statistic
ω

const

Unconditional variance weight

0.6759
4.67***
α

ARCH

Response to squared shocks

0.1350
4.45***
β

GARCH

Volatility persistence

0.6645
10.88***
γi Spline Coefficients
K=9
γ10.0094
0.06
γ2-0.1222
-0.55
γ30.3495
2.12**
γ4-0.5057
-2.28**
γ50.4145
1.73*
γ6-0.0068
-0.03
γ7-0.4969
-2.76***
γ80.7083
4.10***
γ9-0.5085
-4.04***

Persistence:

0.799

Half-life:

3 days