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JSE Securities South African Volatility Index GAS-GARCH Student T Volatility Analysis

Volatility prediction for Friday, October 23rd, 2026

1 Day

176.98%

decreased by 7.81%

1 Week

176.91%

decreased by 7.88%

1 Month

176.60%

decreased by 8.19%

Analysis last updated: Friday, October 23, 2026 at 08:59 PM UTC

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Date Range:

from

10/22/2024

to

10/22/2026

6M ·

1Y ·

2Y ·

5Y ·

10Y ·

All

graph of JSE Securities South African Volatility Index GAS-GARCH-T

News Impact Curve

How returns affect tomorrow's volatility

Volatility Forecast

How volatility evolves over time

Parameter Estimates

Feb 1, 2007 to Oct 15, 2026

Model 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.

𝑓

GAS-GARCH-T Model

Tap to view equation

High persistence: persistence 0.999, shock half-life ~693 daysv = 2.18 · fat tails
ParamValuet-stat
ωlong-run70.7981
3.58***
αscore0.0529
24.24***
βpersistence0.9990
3,254.07***
νDF2.1769
832.46***

0.999

Persistence

693d

Half-life
𝑓

GAS-GARCH-T Model

Tap to view equation

ParameterValuet-statistic
ω

long-run

Long-run variance given a price move

70.7981
3.58***
α

score

Weight on the scaled score

0.0529
24.24***
β

persistence

Volatility persistence

0.9990
3,254.07***
ν

DF

Student-t tail thickness

2.1769
832.46***

Persistence:

0.999

Half-life:

693 days