Ishares S&P 500 EX S&P 1 ETF GJR-GARCH Volatility Analysis
Volatility prediction for Tuesday, October 20th, 2026
1 Day
12.29%
decreased by 0.28%
1 Week
12.36%
decreased by 0.21%
1 Month
12.57%
increased by 0.00%
Analysis last updated: Monday, October 19, 2026 at 09:58 PM UTC
News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
Jul 9, 2025 to Oct 16, 2026Model Insight
Volatility shocks decay with a half-life of 11 trading days, meaning a shock loses half its impact after approximately 11 days.
σ
GJR-GARCH Model
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Shock decay: Shocks decay with a 11-day half-life
| Param | Value | t-stat |
|---|---|---|
| ωconst | 0.0397 | 0.78 |
| αARCH | 0.0000 | 0.00 |
| βGARCH | 0.8904 | 7.65*** |
| γleverage | 0.0997 | 1.10 |
0.940
Persistence11d
Half-lifeσ
GJR-GARCH Model
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| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 0.0397 | 0.78 |
α ARCH Response to squared shocks | 0.0000 | 0.00 |
β GARCH Volatility persistence | 0.8904 | 7.65*** |
γ leverage Additional response to negative shocks | 0.0997 | 1.10 |
Persistence:
0.940
Half-life:
11 days
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