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V-Lab

PSI 20 Portuguese Stock Index GJR-GARCH Volatility Analysis

Volatility prediction for Tuesday, August 25th, 2026

1 Day

10.38%

decreased by 0.33%

1 Week

10.82%

increased by 0.11%

1 Month

12.26%

increased by 1.55%

Analysis last updated: Monday, August 24, 2026 at 05:12 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 Aug 21, 2026

Model Insight

This asset exhibits a strong leverage effect: negative returns increase next-day volatility 101% more than equivalent positive returns.

σ

GJR-GARCH Model

Tap to view equation

ParameterValuet-statistic
ω

const

Unconditional variance weight

0.0244
27.09***
α

ARCH

Response to squared shocks

0.0859
27.35***
β

GARCH

Volatility persistence

0.8569
378.32***
γ

leverage

Additional response to negative shocks

0.0865
11.20***

Persistence:

0.986

Half-life:

49 days