V-Lab
Sonda S.A. GJR-GARCH Volatility Analysis
Volatility prediction for Tuesday, September 15th, 2026
1 Day
27.39%
decreased by 0.60%
1 Week
27.37%
decreased by 0.62%
1 Month
27.34%
decreased by 0.65%
Analysis last updated: Wednesday, September 16, 2026 at 03:17 PM UTC
News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
Nov 9, 2006 to Sep 14, 2026Model Insight
Volatility shocks decay with a half-life of 21 trading days, meaning a shock loses half its impact after approximately 21 days.
σ
GJR-GARCH Model
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Shock decay: Shocks decay with a 21-day half-life
| Param | Value | t-stat |
|---|---|---|
| ωconst | 0.0942 | 3.99*** |
| αARCH | 0.0398 | 3.35*** |
| βGARCH | 0.8883 | 62.43*** |
| γleverage | 0.0796 | 1.90* |
0.968
Persistence21d
Half-lifeσ
GJR-GARCH Model
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| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 0.0942 | 3.99*** |
α ARCH Response to squared shocks | 0.0398 | 3.35*** |
β GARCH Volatility persistence | 0.8883 | 62.43*** |
γ leverage Additional response to negative shocks | 0.0796 | 1.90* |
Persistence:
0.968
Half-life:
21 days
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