V-Lab
Russell 2000 Index GJR-GARCH Volatility Analysis
Volatility prediction for Tuesday, September 15th, 2026
1 Day
15.61%
decreased by 0.49%
1 Week
15.76%
decreased by 0.34%
1 Month
16.31%
increased by 0.21%
Analysis last updated: Tuesday, September 15, 2026 at 12:03 AM UTC
News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
Jan 1, 1990 to Sep 11, 2026Model Insight
With persistence 0.991, volatility shocks have a half-life of 77 trading days (~0.3 years), close to a unit root, so long-run forecasts are highly sensitive to this estimate.
Leverage: Negative returns increase volatility 281% more than positive returns
σ
GJR-GARCH Model
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High persistence: persistence 0.991, shock half-life ~77 daysLeverage: Negative returns increase volatility 281% more than positive returns
| Param | Value | t-stat |
|---|---|---|
| ωconst | 0.0181 | 5.88*** |
| αARCH | 0.0381 | 4.73*** |
| βGARCH | 0.8995 | 137.77*** |
| γleverage | 0.1071 | 5.71*** |
0.991
Persistence77d
Half-lifeσ
GJR-GARCH Model
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| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 0.0181 | 5.88*** |
α ARCH Response to squared shocks | 0.0381 | 4.73*** |
β GARCH Volatility persistence | 0.8995 | 137.77*** |
γ leverage Additional response to negative shocks | 0.1071 | 5.71*** |
Persistence:
0.991
Half-life:
77 days
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