V-Lab
JSE Securities South African Volatility Index GAS-GARCH Student T Volatility Analysis
Volatility prediction for Friday, September 11th, 2026
1 Day
237.02%
1 Week
236.86%
1 Month
236.22%
Analysis last updated: Saturday, September 12, 2026 at 12:49 AM UTC
News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
Feb 1, 2007 to Sep 10, 2026Model Insight
With persistence 0.999, volatility shocks have a half-life of 693 trading days (~2.7 years), close to a unit root, so long-run forecasts are highly sensitive to this estimate. Returns follow a Student-t distribution with v = 2.18 degrees of freedom, capturing fatter tails than a normal distribution.
GAS-GARCH-T Model
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| Param | Value | t-stat |
|---|---|---|
| ωconst | 70.9062 | 3.58*** |
| αARCH | 0.0526 | 23.97*** |
| βGARCH | 0.9990 | 3,254.07*** |
| νDF | 2.1757 | 841.67*** |
0.999
Persistence693d
Half-lifeGAS-GARCH-T Model
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| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 70.9062 | 3.58*** |
α ARCH Response to squared shocks | 0.0526 | 23.97*** |
β GARCH Volatility persistence | 0.9990 | 3,254.07*** |
ν DF Student-t tail thickness | 2.1757 | 841.67*** |
Persistence:
0.999
Half-life:
693 days
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