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V-Lab

PSI 20 Portuguese Stock Index GJR-GARCH Volatility Analysis

Volatility prediction for Wednesday, September 16th, 2026

1 Day

13.20%

decreased by 0.35%

1 Week

13.47%

decreased by 0.08%

1 Month

14.42%

increased by 0.87%

Analysis last updated: Tuesday, September 15, 2026 at 06:43 PM UTC

Date Range:

from

to

6M ·

1Y ·

2Y ·

5Y ·

10Y ·

All

graph of PSI 20 Portuguese Stock Index GJR-GARCH

News Impact Curve

How returns affect tomorrow's volatility

Volatility Forecast

How volatility evolves over time

Parameter Estimates

Dec 30, 1992 to Sep 11, 2026

Model Insight

This asset exhibits a strong leverage effect: negative returns increase next-day volatility 100% more than equivalent positive returns.

σ

GJR-GARCH Model

Tap to view equation

Leverage: Negative returns increase volatility 100% more than positive returns
ParamValuet-stat
ωconst0.0241
6.76***
αARCH0.0859
6.84***
βGARCH0.8572
94.81***
γleverage0.0863
2.80***

0.986

Persistence

50d

Half-life
σ

GJR-GARCH Model

Tap to view equation

ParameterValuet-statistic
ω

const

Unconditional variance weight

0.0241
6.76***
α

ARCH

Response to squared shocks

0.0859
6.84***
β

GARCH

Volatility persistence

0.8572
94.81***
γ

leverage

Additional response to negative shocks

0.0863
2.80***

Persistence:

0.986

Half-life:

50 days