V-Lab
JSE Securities South African Volatility Index GAS-GARCH Student T Volatility Analysis
Volatility prediction for Friday, July 31st, 2026
1 Day
391.43%
decreased by 14.87%
1 Week
391.09%
decreased by 15.21%
1 Month
389.72%
decreased by 16.58%
Analysis last updated: Friday, July 31, 2026 at 08:05 PM UTC
News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
Feb 1, 2007 to Apr 4, 2025Model 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 = 2.15 degrees of freedom, capturing fatter tails than a normal distribution.
𝑓
GAS-GARCH-T Model
Tap to view equation
| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 72.2837 | 14.45*** |
α ARCH Response to squared shocks | 0.0497 | 89.61*** |
β GARCH Volatility persistence | 0.9990 | |
ν DF Student-t tail thickness | 2.1501 | 3,765.56*** |
Persistence:
0.999
Half-life:
693 days
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