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
News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
Jul 18, 1997 to Jul 17, 2026Model 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
| Parameter | Value | t-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
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