S&P Composite 1500 Index GJR-GARCH Volatility Analysis
Volatility prediction for Friday, October 23rd, 2026
1 Day
13.92%
increased by 1.95%
1 Week
14.09%
increased by 2.12%
1 Month
14.67%
increased by 2.70%
Analysis last updated: Thursday, October 22, 2026 at 11:08 PM UTC
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News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
Oct 31, 1994 to Oct 16, 2026Model Insight
Volatility shocks decay with a half-life of 35 trading days, meaning a shock loses half its impact after approximately 35 days.
σ
GJR-GARCH Model
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Shock decay: Shocks decay with a 35-day half-life
| Param | Value | t-stat |
|---|---|---|
| ωconst | 0.0245 | 4.98*** |
| αARCH | 0.0000 | 0.00 |
| βGARCH | 0.8903 | 97.48*** |
| γleverage | 0.1803 | 7.63*** |
0.980
Persistence35d
Half-lifeσ
GJR-GARCH Model
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| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 0.0245 | 4.98*** |
α ARCH Response to squared shocks | 0.0000 | 0.00 |
β GARCH Volatility persistence | 0.8903 | 97.48*** |
γ leverage Additional response to negative shocks | 0.1803 | 7.63*** |
Persistence:
0.980
Half-life:
35 days
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