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V-Lab

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

Volatility prediction for Friday, July 24th, 2026

1 Day

119.20%

increased by 22.12%

1 Week

107.62%

increased by 10.54%

1 Month

86.10%

decreased by 10.98%

Analysis last updated: Friday, July 24, 2026 at 11:19 PM 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 Apr 4, 2025

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 4 trading days.

τ

Zero Slope Spline-GARCH Model

Tap to view equation

ParameterValuet-statistic
ω

const

Unconditional variance weight

0.6657
4.99***
α

ARCH

Response to squared shocks

0.1214
4.35***
β

GARCH

Volatility persistence

0.7166
12.65***
γi Spline Coefficients
K=6
γ1-0.1454
-1.93*
γ20.2758
2.40**
γ3-0.2770
-2.65***
γ40.3195
3.00***
γ5-0.3248
-3.71***
γ60.2030
3.52***

Persistence:

0.838

Half-life:

4 days