V-Lab
S&P 500 Index Asy. Power MEM Volatility Analysis
Volatility prediction for Wednesday, October 7th, 2026
1 Day
9.87%
1 Week
9.84%
1 Month
9.73%
Analysis last updated: Wednesday, October 7, 2026 at 12:03 AM UTC
News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
Jan 1, 1990 to Oct 2, 2026Model Insight
This asset exhibits a strong leverage effect: negative returns increase next-day volatility 101% more than equivalent positive returns. The volatility power δ = 1.04 sits below 2, so large shocks influence volatility less than quadratically, a more outlier-robust response than standard GARCH.
APMEM Model
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| Param | Value | t-stat |
|---|---|---|
| ωconst | 0.0327 | 9.80*** |
| αARCH | 0.1890 | 14.63*** |
| βGARCH | 0.7928 | 60.90*** |
| γleverage | 0.3227 | 8.22*** |
| δpower | 1.0392 | 8.72*** |
0.944
Persistence12d
Half-lifeAPMEM Model
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| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 0.0327 | 9.80*** |
α ARCH Response to squared shocks | 0.1890 | 14.63*** |
β GARCH Volatility persistence | 0.7928 | 60.90*** |
γ leverage Additional response to negative shocks | 0.3227 | 8.22*** |
δ power Transformation power | 1.0392 | 8.72*** |
Persistence:
0.944
Half-life:
12 days
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