V-Lab
Korea Stock Exchange KOSPI 200 Index GJR-GARCH Volatility Analysis
Volatility prediction for Monday, September 28th, 2026
1 Day
41.95%
decreased by 1.57%
1 Week
41.90%
decreased by 1.62%
1 Month
41.71%
decreased by 1.81%
Analysis last updated: Friday, September 25, 2026 at 08:55 PM UTC
News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
Jan 3, 1990 to Sep 23, 2026Model Insight
With persistence 0.996, volatility shocks have a half-life of 193 trading days (~0.8 years), close to a unit root, so long-run forecasts are highly sensitive to this estimate.
Leverage: Negative returns increase volatility 124% more than positive returns
σ
GJR-GARCH Model
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High persistence: persistence 0.996, shock half-life ~193 daysLeverage: Negative returns increase volatility 124% more than positive returns
| Param | Value | t-stat |
|---|---|---|
| ωconst | 0.0170 | 4.44*** |
| αARCH | 0.0483 | 5.40*** |
| βGARCH | 0.9182 | 145.68*** |
| γleverage | 0.0598 | 3.37*** |
0.996
Persistence193d
Half-lifeσ
GJR-GARCH Model
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| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 0.0170 | 4.44*** |
α ARCH Response to squared shocks | 0.0483 | 5.40*** |
β GARCH Volatility persistence | 0.9182 | 145.68*** |
γ leverage Additional response to negative shocks | 0.0598 | 3.37*** |
Persistence:
0.996
Half-life:
193 days
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