V-Lab
Ishares S&P 500 EX S&P 1 ETF Asy. MEM Volatility Analysis
Volatility prediction for Wednesday, September 16th, 2026
1 Day
9.29%
decreased by 0.27%
1 Week
9.33%
decreased by 0.23%
1 Month
9.52%
decreased by 0.04%
Analysis last updated: Tuesday, September 15, 2026 at 09:34 PM UTC
News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
Jul 9, 2025 to Sep 11, 2026Model Insight
With persistence 0.999, volatility shocks have a half-life of 785 trading days (~3.1 years), close to a unit root, so long-run forecasts are highly sensitive to this estimate.
μ
AMEM Model
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High persistence: persistence 0.999, shock half-life ~785 days
| Param | Value | t-stat |
|---|---|---|
| ωconst | 0.0020 | 0.89 |
| αARCH | 0.0491 | 1.20 |
| βGARCH | 0.9368 | 34.58*** |
| γleverage | 0.0264 | 0.28 |
0.999
Persistence785d
Half-lifeμ
AMEM Model
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| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 0.0020 | 0.89 |
α ARCH Response to squared shocks | 0.0491 | 1.20 |
β GARCH Volatility persistence | 0.9368 | 34.58*** |
γ leverage Additional response to negative shocks | 0.0264 | 0.28 |
Persistence:
0.999
Half-life:
785 days
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