V-Lab
S&P 100 Index MEM Volatility Analysis
Volatility prediction for Wednesday, September 16th, 2026
1 Day
9.50%
decreased by 0.18%
1 Week
9.91%
increased by 0.23%
1 Month
11.30%
increased by 1.62%
Analysis last updated: Tuesday, September 15, 2026 at 11:10 PM 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
Volatility shocks decay with a half-life of 50 trading days, meaning a shock loses half its impact after approximately 50 days.
μ
MEM Model
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Shock decay: Shocks decay with a 50-day half-life
| Param | Value | t-stat |
|---|---|---|
| ωconst | 0.0212 | 2.86*** |
| αARCH | 0.2213 | 14.31*** |
| βGARCH | 0.7649 | 70.42*** |
0.986
Persistence50d
Half-lifeμ
MEM Model
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| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 0.0212 | 2.86*** |
α ARCH Response to squared shocks | 0.2213 | 14.31*** |
β GARCH Volatility persistence | 0.7649 | 70.42*** |
Persistence:
0.986
Half-life:
50 days
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