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V-Lab

PSI 20 Portuguese Stock Index Asy. MEM Volatility Analysis

Volatility prediction for Monday, July 20th, 2026

1 Day

12.97%

decreased by 0.93%

1 Week

13.28%

decreased by 0.62%

1 Month

14.34%

increased by 0.44%

Analysis last updated: Friday, July 17, 2026 at 05:05 PM UTC

Date Range:

from

to

6M ·

1Y ·

2Y ·

5Y ·

10Y ·

All

graph of PSI 20 Portuguese Stock Index AMEM

News Impact Curve

How returns affect tomorrow's volatility

Volatility Forecast

How volatility evolves over time

Parameter Estimates

Jul 18, 1997 to Jul 17, 2026

Model Insight

This asset exhibits a notable leverage effect: negative returns increase next-day volatility 58% more than equivalent positive returns.

μ

AMEM Model

Tap to view equation

ParameterValuet-statistic
ω

const

Unconditional variance weight

0.0258
34.49***
α

ARCH

Response to squared shocks

0.1804
38.58***
β

GARCH

Volatility persistence

0.7527
268.33***
γ

leverage

Additional response to negative shocks

0.1049
14.02***

Persistence:

0.986

Half-life:

48 days