S&P 100 Index GJR-GARCH Volatility Analysis
Volatility prediction for Thursday, October 22nd, 2026
1 Day
12.26%
decreased by 0.40%
1 Week
12.46%
decreased by 0.20%
1 Month
13.17%
increased by 0.51%
Analysis last updated: Wednesday, October 21, 2026 at 11:01 PM 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
GJR-GARCH Model
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Leverage: volatility responds almost entirely to negative shocks
| Param | Value | t-stat |
|---|---|---|
| ωconst | 0.0208 | 4.92*** |
| αARCH | 0.0048 | 0.52 |
| βGARCH | 0.9022 | 94.34*** |
| γleverage | 0.1506 | 6.98*** |
0.982
Persistence39d
Half-lifeσ
GJR-GARCH Model
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| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 0.0208 | 4.92*** |
α ARCH Response to squared shocks | 0.0048 | 0.52 |
β GARCH Volatility persistence | 0.9022 | 94.34*** |
γ leverage Additional response to negative shocks | 0.1506 | 6.98*** |
Persistence:
0.982
Half-life:
39 days
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