S&P 500 Index EGARCH Volatility Analysis
Volatility prediction for Monday, October 19th, 2026
1 Day
13.68%
increased by 2.01%
1 Week
13.85%
increased by 2.18%
1 Month
14.43%
increased by 2.76%
Analysis last updated: Saturday, October 17, 2026 at 12:24 AM UTC
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News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
Jan 1, 1990 to Oct 16, 2026Model Insight
This asset exhibits a strong leverage effect: volatility responds almost entirely to negative shocks. The ARCH response to positive shocks is negligible.
σ
EGARCH Model
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Leverage: volatility responds almost entirely to negative shocks
| Param | Value | t-stat |
|---|---|---|
| ωconst | 0.0040 | 0.35 |
| αARCH | 0.1495 | 9.02*** |
| βGARCH | 0.9715 | 173.12*** |
| γleverage | -0.1288 | -8.62*** |
0.972
Persistence24d
Half-lifeσ
EGARCH Model
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| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 0.0040 | 0.35 |
α ARCH Response to squared shocks | 0.1495 | 9.02*** |
β GARCH Volatility persistence | 0.9715 | 173.12*** |
γ leverage Additional response to negative shocks | -0.1288 | -8.62*** |
Persistence:
0.972
Half-life:
24 days
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