S&P 500 Equal Weight Index (EWI) GJR-GARCH Volatility Analysis
Volatility prediction for Monday, October 12th, 2026
1 Day
10.99%
decreased by 0.32%
1 Week
11.24%
decreased by 0.07%
1 Month
12.10%
increased by 0.79%
Analysis last updated: Saturday, October 10, 2026 at 02:26 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 9, 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
GJR-GARCH Model
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Leverage: volatility responds almost entirely to negative shocks
| Param | Value | t-stat |
|---|---|---|
| ωconst | 0.0186 | 5.57*** |
| αARCH | 0.0175 | 2.07** |
| βGARCH | 0.8987 | 122.79*** |
| γleverage | 0.1369 | 6.77*** |
0.985
Persistence45d
Half-lifeσ
GJR-GARCH Model
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| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 0.0186 | 5.57*** |
α ARCH Response to squared shocks | 0.0175 | 2.07** |
β GARCH Volatility persistence | 0.8987 | 122.79*** |
γ leverage Additional response to negative shocks | 0.1369 | 6.77*** |
Persistence:
0.985
Half-life:
45 days
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