V-Lab
S&P Composite 1500 Index GJR-GARCH Volatility Analysis
Volatility prediction for Monday, September 21st, 2026
1 Day
11.38%
decreased by 0.39%
1 Week
11.69%
decreased by 0.08%
1 Month
12.73%
increased by 0.96%
Analysis last updated: Saturday, September 19, 2026 at 12:01 AM UTC
News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
Oct 31, 1994 to Sep 18, 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 | 0.0246 | 4.98*** |
| αARCH | 0.0000 | 0.00 |
| βGARCH | 0.8903 | 97.38*** |
| γleverage | 0.1804 | 7.59*** |
0.980
Persistence35d
Half-lifeσ
GJR-GARCH Model
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| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 0.0246 | 4.98*** |
α ARCH Response to squared shocks | 0.0000 | 0.00 |
β GARCH Volatility persistence | 0.8903 | 97.38*** |
γ leverage Additional response to negative shocks | 0.1804 | 7.59*** |
Persistence:
0.980
Half-life:
35 days
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