V-Lab
S&P 100 Index Asy. MEM Volatility Analysis
Volatility prediction for Friday, September 18th, 2026
1 Day
12.65%
decreased by 1.09%
1 Week
12.83%
decreased by 0.91%
1 Month
13.47%
decreased by 0.27%
Analysis last updated: Friday, September 18, 2026 at 12:05 AM UTC
News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
Jan 1, 1990 to Sep 11, 2026Model Insight
This asset exhibits a strong leverage effect: negative returns increase next-day volatility 175% more than equivalent positive returns.
μ
AMEM Model
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Leverage: Negative returns increase volatility 175% more than positive returns
| Param | Value | t-stat |
|---|---|---|
| ωconst | 0.0224 | 9.20*** |
| αARCH | 0.0993 | 6.18*** |
| βGARCH | 0.7934 | 75.27*** |
| γleverage | 0.1743 | 6.18*** |
0.980
Persistence34d
Half-lifeμ
AMEM Model
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| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 0.0224 | 9.20*** |
α ARCH Response to squared shocks | 0.0993 | 6.18*** |
β GARCH Volatility persistence | 0.7934 | 75.27*** |
γ leverage Additional response to negative shocks | 0.1743 | 6.18*** |
Persistence:
0.980
Half-life:
34 days
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