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JSE Securities South African Volatility Index GJR-GARCH Volatility Analysis

Volatility prediction for Friday, September 4th, 2026

1 Day

86.05%

decreased by 6.71%

1 Week

83.99%

decreased by 8.77%

1 Month

77.96%

decreased by 14.80%

Analysis last updated: Friday, September 4, 2026 at 11:27 PM UTC

Date Range:

from

to

6M ·

1Y ·

2Y ·

5Y ·

10Y ·

All

graph of JSE Securities South African Volatility Index GJR-GARCH

News Impact Curve

How returns affect tomorrow's volatility

Volatility Forecast

How volatility evolves over time

Parameter Estimates

Feb 1, 2007 to Aug 27, 2026

Model Insight

Volatility shocks decay with a half-life of 12 trading days, meaning a shock loses half its impact after approximately 12 days.

σ

GJR-GARCH Model

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Shock decay: Shocks decay with a 12-day half-life
ParamValuet-stat
ωconst0.9427
4.36***
αARCH0.1293
3.22***
βGARCH0.8314
32.09***
γleverage-0.0357
-0.48

0.943

Persistence

12d

Half-life
σ

GJR-GARCH Model

Tap to view equation

ParameterValuet-statistic
ω

const

Unconditional variance weight

0.9427
4.36***
α

ARCH

Response to squared shocks

0.1293
3.22***
β

GARCH

Volatility persistence

0.8314
32.09***
γ

leverage

Additional response to negative shocks

-0.0357
-0.48

Persistence:

0.943

Half-life:

12 days