PSI 20 Portuguese Stock Index GJR-GARCH Volatility Analysis
Volatility prediction for Monday, October 12th, 2026
1 Day
14.94%
increased by 0.25%
1 Week
15.13%
increased by 0.44%
1 Month
15.83%
increased by 1.14%
Analysis last updated: Friday, October 9, 2026 at 05:06 PM UTC
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News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
Dec 30, 1992 to Oct 9, 2026Model Insight
This asset exhibits a strong leverage effect: negative returns increase next-day volatility 100% more than equivalent positive returns.
σ
GJR-GARCH Model
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Leverage: Negative returns increase volatility 100% more than positive returns
| Param | Value | t-stat |
|---|---|---|
| ωconst | 0.0243 | 6.81*** |
| αARCH | 0.0856 | 6.83*** |
| βGARCH | 0.8574 | 95.08*** |
| γleverage | 0.0859 | 2.79*** |
0.986
Persistence49d
Half-lifeσ
GJR-GARCH Model
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| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 0.0243 | 6.81*** |
α ARCH Response to squared shocks | 0.0856 | 6.83*** |
β GARCH Volatility persistence | 0.8574 | 95.08*** |
γ leverage Additional response to negative shocks | 0.0859 | 2.79*** |
Persistence:
0.986
Half-life:
49 days
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